---

MS General Surgery Year-1 - September 2025

Detailed Answers (Standard Textbook)

---

Q.1 Management of Arterial Stenosis and Occlusion in Peripheral Vascular Disease + Recent Advances (30 Marks)

Definition & Pathophysiology

---

Assessment

• Absent peripheral pulses (popliteal, dorsalis pedis, posterior tibial)
• Buerger's test positive (pallor on elevation, rubor on dependency)
• Capillary refill >2 sec
• Trophic changes: hair loss, shiny skin, thickened nails

• ABI (Doppler)
• Duplex ultrasonography - first-line
• CT Angiography (CTA) - gold standard for planning
• MR Angiography (MRA)
• Digital subtraction angiography (DSA) - when intervention planned

---

Medical Management

1. Risk factor modification:
   • Smoking cessation (most important - reduces progression by 50%)
   • Diabetic control (HbA1c <7%)
   • Hypertension control (<130/80 mmHg)
   • Statin therapy (atorvastatin 40-80 mg) - reduces cardiovascular events AND improves walking distance
   • Antiplatelet therapy: Aspirin 75-150 mg or Clopidogrel 75 mg (preferred in PAD - CAPRIE trial)
2. Exercise therapy:
   • Supervised exercise programme (30-45 min, 3x/week, for 12 weeks) - FIRST LINE for claudication
   • Improves walking distance by 100-150%
3. Pharmacotherapy:
   • Cilostazol 100 mg BD - phosphodiesterase III inhibitor; improves claudication (CI in heart failure)
   • Naftidrofuryl oxalate - serotonin receptor antagonist; modest benefit
   • Pentoxifylline - reduces blood viscosity (less evidence)
4. Foot care: Daily inspection, protective footwear, podiatry referral

---

Endovascular Management (Catheter-based)

• TASC A lesions: Short single stenosis <3 cm - best for endovascular
• TASC B: Multiple lesions, each <3 cm - endovascular preferred
• TASC C: Multiple lesions >3 cm - surgery preferred
• TASC D: Complete occlusions - surgery preferred

Procedures:

1. Percutaneous Transluminal Angioplasty (PTA):
   • Balloon catheter inserted over guidewire, inflated at stenosis
   • Best results: iliac and femoral arteries
   • Success rate >90% for iliac; 60-70% for femoropopliteal
2. Stenting:
   • Bare metal stents (BMS) - standard
   • Drug-eluting stents (DES) - paclitaxel-coated; reduces restenosis
   • Self-expanding nitinol stents - preferred in femoropopliteal (flexibility)
   • Covered stents (ePTFE-coated) - for complex/occlusive disease
3. Atherectomy:
   • Directional atherectomy (SilverHawk device)
   • Rotational atherectomy
   • Laser atherectomy
   • Orbital atherectomy
   • Especially useful for calcified lesions before stenting
4. Thrombolysis:
   • Catheter-directed thrombolysis (CDT) with tPA or urokinase
   • For acute-on-chronic occlusion
   • Converts acute to elective intervention

---

Surgical Management

1. Aortoiliac Disease (Leriche Syndrome: claudication, absent femoral pulses, impotence in males)

• Gold standard for bilateral aortoiliac disease
• Dacron or ePTFE graft (aortobifemoral Y-graft)
• 5-year patency >85-90%
• Steps: Transperitoneal or retroperitoneal approach; aortic clamping; proximal end-to-end/end-to-side anastomosis; femoral tunnel; distal end-to-side anastomosis

• For high-risk patients unfit for aortic surgery
• Axillobifemoral: extra-anatomic; 5-yr patency ~70%

2. Femoropopliteal Disease

• Above-knee bypass: Reversed long saphenous vein (LSV) or synthetic graft (Dacron/ePTFE); 5-yr patency: vein >70%, synthetic ~50%
• Below-knee bypass: Reversed LSV preferred (5-yr patency ~65%); synthetic graft poor outcomes
• In-situ vein bypass: vein left in situ, valves destroyed with valvulotome

• Widening of profunda femoris artery origin
• For patients with patent deep femoral artery as collateral

3. Infrapopliteal / Tibial Disease (Critical Limb Ischemia)

• Femoro-tibial bypass using vein conduit
• Pedal bypass (to dorsalis pedis/posterior tibial)
• Requires high-quality duplex mapping preoperatively

4. Endarterectomy

• Surgical removal of intimal plaque
• Best for short segment iliac or common femoral artery disease
• Common femoral endarterectomy (CFE): frequently combined with distal bypass

5. Amputation

• Toe/ray amputation - for digital gangrene with patent tibial vessels
• Transmetatarsal amputation
• Below-knee amputation (BKA) / Transtibial - preferred (better rehabilitation)
• Above-knee amputation (AKA) / Transfemoral - for failed BKA or knee joint disease
• Symes amputation (through ankle)

---

Acute Limb Ischemia (ALI) - Management

• Category I (viable): No immediate threat - anticoagulate
• Category IIa (marginally threatened): CDT or surgical embolectomy
• Category IIb (immediately threatened): Emergency surgical embolectomy
• Category III (irreversible): Amputation

• Balloon catheter passed beyond clot, inflated, withdrawn to extract thrombus
• Through groin incision under local/regional anesthesia
• Anticoagulate with heparin before and after
• On-table angiogram to confirm complete clearance
• Post-reperfusion monitoring for compartment syndrome (fasciotomy if ICP >30 mmHg)

---

Recent Advances (Important for 30-mark question)

1. Drug-coated balloons (DCB): Paclitaxel-coated balloons for femoropopliteal disease; reduces restenosis without leaving a permanent implant (IN.PACT SFA trial - sustained 12-month patency)
2. Bioresorbable vascular scaffolds (BVS): Absorbable stents that provide temporary support then dissolve
3. Covered stents / Stent-grafts: VIABAHN endoprosthesis for long-segment femoropopliteal occlusions; excellent patency
4. Endovascular Aneurysm Repair (EVAR) / TEVAR: For aortic aneurysms; minimally invasive alternative to open repair
5. Hybrid procedures: Combining endovascular + open surgery in same session (e.g., iliac stenting + femoral endarterectomy + bypass)
6. Robotic-assisted vascular surgery: Emerging role in aortofemoral bypass
7. Gene therapy and stem cell therapy: Therapeutic angiogenesis using vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF); intramuscular injection of autologous bone marrow-derived stem cells (BMAC); improves collateral formation in no-option CLI
8. Spinal cord stimulation: For non-reconstructable CLI and rest pain; improves microcirculation
9. Endovascular re-entry catheters (Outback, Pioneer): For chronic total occlusions (CTOs), allowing true-lumen re-entry after subintimal tracking
10. CLTI (Chronic Limb-Threatening Ischemia): New unified terminology replacing CLI (2019 Global Vascular Guidelines); emphasizes wound, ischemia, and foot infection (WIfI classification) for limb staging and revascularization benefit estimation
11. Rivaroxaban (low-dose) + Aspirin: COMPASS trial showed 24% reduction in major adverse cardiovascular events (MACE) and limb events in PAD patients
12. Vorapaxar: PAR-1 antagonist; reduces recurrent peripheral arterial events (TRA 2P-TIMI 50 trial)

---

Q.2 Thoracotomy: Indications, Complications, Approach/Steps + Thoracoscopy, Mediastinoscopy, VATS (30 Marks)

THORACOTOMY

Indications

• Pulmonary resections: lobectomy, pneumonectomy, segmentectomy (for lung carcinoma, bronchiectasis, lung abscess)
• Bullous/emphysematous disease
• Bronchopleural fistula repair
• Pulmonary metastasectomy

• Empyema thoracis (stage III - organized/fibrinous)
• Malignant pleural mesothelioma (extrapleural pneumonectomy)
• Persistent pneumothorax / recurrent pneumothorax

• Thymoma / thymectomy
• Mediastinal tumors and cysts
• Pericardial surgery (pericardiectomy for constrictive pericarditis)

• Esophageal resection (Ivor Lewis, McKeown, transhiatal esophagectomy)
• Esophageal perforation repair (Boerhaave syndrome)
• Achalasia - Heller's myotomy (now mostly laparoscopic)

• Open heart surgery (median sternotomy is the approach)
• Cardiac trauma (emergency resuscitative thoracotomy)

• Thoracic aortic surgery
• Patent ductus arteriosus (PDA) ligation
• Coarctation of aorta repair

• Massive hemothorax (>1500 mL at drain insertion, or >200 mL/hr for 2-4 hours)
• Suspected cardiac or great vessel injury
• Diaphragmatic rupture with herniation

Approaches to Thoracotomy

• Most versatile, best exposure
• Patient: lateral decubitus position (full or modified)
• Incision: from anterior axillary line, curving posteriorly below tip of scapula, following rib contour
• Layers: skin, subcutaneous tissue, latissimus dorsi, serratus anterior (partially), intercostal muscles
• Entry: usually 4th, 5th, or 6th intercostal space (ICS) - cut through periosteum and intercostal muscles just above the lower rib (avoids neurovascular bundle)
• Rib spreader (Finochietto) placed
• Uses: pneumonectomy, lobectomy, esophagectomy

• Patient: supine with roll under ipsilateral chest
• Incision: follows anterior rib contour, below nipple in men, infra-mammary crease in women
• Limited access but rapidly performed
• Uses: emergency resuscitative thoracotomy, access to anterior mediastinum, cardiac

• Standard for cardiac surgery
• Patient: supine
• Full-length sternum split with oscillating saw
• Rib spreader (sternal retractor)
• Closure: stainless steel wires (6-8)
• Uses: CABG, valve surgery, bilateral lung procedures, anterior mediastinal tumors

• Bilateral anterolateral thoracotomies connected across midline through transverse sternotomy
• Excellent bilateral exposure
• Bilateral lung transplant, bilateral metastasectomy

• Limited access for apical procedures, sympathectomy, bullectomy

Steps of Posterolateral Thoracotomy

1. General anesthesia with double-lumen endotracheal tube (DLT) for one-lung ventilation
2. Lateral decubitus position - bean bag support
3. Padding all pressure points
4. Skin incision (as above)
5. Division of latissimus dorsi (or splitting)
6. Retraction of serratus anterior
7. Counting ribs - identify correct ICS
8. Division of intercostal muscles (just above lower rib)
9. Division of posterior intercostal neurovascular bundle if needed - lateral to costal groove
10. Insertion of Finochietto rib spreader - gradual opening
11. Operative procedure
12. Two intercostal drains (apical for air, basal for fluid)
13. Pericostal sutures (2-3) for rib approximation
14. Layered closure: intercostal, serratus, latissimus, subcutaneous, skin

Complications

• Hemorrhage (intercostal vessels, pulmonary vessels, great vessels)
• Air embolism
• Inadvertent injury to adjacent structures (phrenic nerve, esophagus, thoracic duct)
• Arrhythmia

• Respiratory failure / atelectasis
• Pneumonia (most common postoperative complication)
• Prolonged air leak (>7 days after lung resection)
• Hemothorax / retained hemothorax
• Empyema / surgical site infection
• Bronchopleural fistula (especially after pneumonectomy)
• Cardiac herniation (after pneumonectomy if pericardium opened)
• Postpneumonectomy pulmonary edema
• Arrhythmias (atrial fibrillation - most common after pulmonary resection)
• Pulmonary embolism

• Post-thoracotomy pain syndrome (intercostal nerve damage)
• Winged scapula (long thoracic nerve injury - serratus anterior palsy)
• Shoulder stiffness
• Chylothorax (thoracic duct injury)
• Post-pneumonectomy syndrome (mediastinal shift)
• Respiratory insufficiency

---

THORACOSCOPY (Diagnostic)

1. Medical thoracoscopy (pleuroscopy) - performed by pulmonologist under sedation and local anesthesia, using single port
2. VATS - performed by surgeon under GA, using 2-4 ports

• Undiagnosed pleural effusion (most common indication)
• Pleural biopsy
• Staging of mesothelioma
• Diagnosis of pneumothorax, pleural masses
• Talc pleurodesis for recurrent effusion/pneumothorax

• Local anesthesia (medical) or GA (surgical)
• Patient lateral position
• 5-10 mm trocar in 4th-6th ICS, mid-axillary line
• Introduction of thoracoscope (0° or 30°)
• Examination of entire pleural surface, diaphragm, parietal/visceral pleura
• Biopsy under direct vision
• Talc insufflation if pleurodesis needed
• Intercostal drain placed at end

---

MEDIASTINOSCOPY

Cervical Mediastinoscopy (Carlens, 1959)

• Staging of lung cancer (N2/N3 nodal status) - most common indication
• Tissue diagnosis of mediastinal masses (lymphoma, sarcoidosis)
• Superior vena cava syndrome
• Assessment of nodes before surgical resection

1. GA, supine, neck extended (roll under shoulders)
2. 2-3 cm transverse incision above suprasternal notch
3. Dissection through strap muscles
4. Development of pretracheal plane by blunt finger dissection
5. Introduction of mediastinoscope along anterior trachea into superior mediastinum
6. Visualization and biopsy of paratracheal, tracheobronchial, subcarinal nodes
7. Excellent hemostasis essential (innominate artery, superior vena cava, azygos vein adjacent)
8. Closure in layers

• Left 2nd costal cartilage removed
• Access to aortopulmonary window (station 5,6) and prevascular nodes
• For left upper lobe tumors

• Hemorrhage (innominate artery injury - most feared, 0.1%)
• Pneumothorax (0.5-1%)
• Recurrent laryngeal nerve injury
• Infection / mediastinitis
• Tracheal/esophageal injury
• Air embolism

---

VIDEO-ASSISTED THORACOSCOPIC SURGERY (VATS)

Indications

• Pleural biopsy, lung biopsy (VATS wedge)
• Mediastinal biopsy
• Diagnosis of interstitial lung disease (ILD) - VATS lung biopsy is gold standard

• VATS lobectomy (standard of care for Stage I-II NSCLC)
• VATS segmentectomy, wedge resection
• Bullectomy for pneumothorax
• VATS pleurectomy/decortication
• Hyperhidrosis (thoracoscopic sympathectomy - T2/T3 division)

• Thymectomy (for myasthenia gravis or thymoma)
• Mediastinal cyst/tumor excision
• Esophageal surgery (VATS esophagomyotomy, esophagectomy)

• Pericardial window for effusion

Steps of VATS Lobectomy

1. GA with double-lumen ETT (one-lung ventilation)
2. Lateral decubitus position
3. Monitor port: 0.5-1 cm in 7th-8th ICS, posterior axillary line (for camera)
4. Utility port: 4-6 cm in 4th-5th ICS, anterior axillary line (working port)
5. Additional 0.5-1 cm ports for instruments
6. Lung collapsed on operative side
7. Systematic dissection of pulmonary vein, artery, bronchus (vein first principle)
8. Endoscopic staplers (linear) used for vascular and bronchial division
9. Specimen placed in bag, extracted through utility port
10. Systematic lymph node dissection
11. Underwater leak test
12. Single chest drain placed

VATS vs Open Thoracotomy

Recent Advances in Thoracic Surgery

1. Uniportal VATS: Single 3-4 cm incision; all instruments and camera through one port; pioneered by Gonzalez-Rivas; less post-operative pain, faster recovery
2. Robotic-assisted thoracic surgery (RATS): da Vinci system; 3D visualization, articulated instruments; superior for complex mediastinal dissection and sleeve resections
3. Non-intubated VATS (awake VATS): Avoids complications of intubation and general anesthesia; performed under spontaneous ventilation with locoregional anesthesia; growing evidence especially in high-risk patients
4. EBUS (Endobronchial Ultrasound): Real-time ultrasound-guided transbronchial needle aspiration (EBUS-TBNA); replaced mediastinoscopy for nodal staging in many centers; less invasive
5. EUS (Endoscopic Ultrasound): Trans-esophageal access to posterior mediastinal nodes (stations 8, 9) - combined EBUS+EUS covers all mediastinal stations
6. Navigation bronchoscopy: Electromagnetic navigation bronchoscopy (ENB) and cone-beam CT fluoroscopy for peripheral lung lesions not accessible by standard bronchoscopy
7. Sublobar resections in early NSCLC: JCOG0802/WJOG4607L trial (2022) demonstrated anatomical segmentectomy non-inferior to lobectomy for tumors ≤2 cm - paradigm shift
8. Stereotactic body radiotherapy (SBRT): Alternative to surgery in high-risk Stage I NSCLC patients

---

Q.3 Short Answer Questions (20 Marks)

Q.3(a) Laparoscopic Access and Port Placement (10 Marks)

Establishing Pneumoperitoneum

---

Methods of Access

1. Closed (Veress Needle) Technique

1. Patient supine, head-down (Trendelenburg) tilt
2. Umbilicus elevated with towel clips or grabbed
3. Small skin incision (1 cm) at umbilicus
4. Veress needle inserted at 45° toward pelvis (90° if obese)
5. Double click felt as needle passes through fascia and peritoneum
6. Saline drop test (Hanging drop test): Drop of saline placed at needle hub - sucked in confirming intraperitoneal position
7. Aspiration test: Aspirate - should yield nothing; if blood (vascular injury) or bowel contents (GI injury) - remove and reassess
8. Opening pressure: <8 mmHg confirms intraperitoneal position (high pressure = needle tip in omentum/preperitoneal fat)
9. Insufflation at 1-2 L/min initially, then full flow (6 L/min)
10. At 12-15 mmHg, remove Veress, insert first trocar (10-12 mm) blindly at umbilicus
11. Camera introduced

---

2. Open (Hasson) Technique

1. 2-3 cm vertical/infraumbilical incision
2. Scar tissue dissected down to linea alba
3. Small incision in linea alba under direct vision
4. Artery forceps used to open peritoneum (S-retractors used)
5. Digital exploration to confirm entry and check for adhesions
6. Hasson trocar placed (blunt-tipped, with olive/cone and wing nut to create seal)
7. Stay sutures (0-Vicryl) placed through fascia either side to hold trocar and assist closure
8. Insufflation through Hasson trocar

---

3. Direct Entry Technique

• No Veress needle
• Sharp trocar inserted directly through umbilicus without prior insufflation
• Faster; evidence suggests comparable safety to Veress
• Requires experience; not used in previous abdominal surgery

4. Optical (Visual) Entry Technique

• Trocar with transparent tip (Ternamian, Visiport, Optiview)
• Camera inserted into trocar while advancing through layers
• Each layer visualized and identified before entry
• Reduces inadvertent visceral/vascular injury

---

Port Placement Principles

1. Umbilical port for camera first
2. Camera port at a minimum 15 cm from target organ (working distance)
3. Working ports: 30-45° on either side of camera port axis
4. Distance between ports: >5-7 cm (prevents fencing)
5. Avoid natural folds and blood vessels (check with transillumination)
6. Epigastric vessels (inferior): visible through abdominal wall with external illumination; run 5-8 cm lateral to midline

• 5 mm: most instruments (scissors, graspers, clip applicators, cautery)
• 10-12 mm: camera, linear stapler, specimen retrieval, clip applicator (large)
• 15 mm: hand port (HALS)

Specific Examples

Complications of Laparoscopic Access

1. Vascular injury: Aorta, IVC, iliac vessels (Veress insertion) - incidence 0.04%, mortality 50%
2. Bowel injury: Small bowel adhesions at umbilicus; may be missed at time of insertion
3. Bladder injury: If Foley catheter not placed, full bladder at suprapubic port
4. Omental/bowel emphysema: Extraperitoneal insufflation
5. Gas embolism: CO₂ into vein (rare)
6. Port site hernia: >10 mm ports require fascial closure; Richter's hernia common at port sites
7. Port site metastasis: Rare (0.8-1.1%) in cancer surgery - use specimen retrieval bags
8. Shoulder tip pain: Diaphragmatic irritation from residual CO₂

---

Q.3(b) Therapeutic Oesophagogastroduodenoscopy (OGD) / Upper GI Endoscopy (10 Marks)

Equipment

• Forward-viewing video endoscope (9-11 mm diameter)
• Light source, video processor, monitor
• Accessories: biopsy forceps, injection needle, snare, clips (hemoclips), argon plasma coagulator, banding device, balloon dilator, stents, ablation catheter

---

Indications for Therapeutic OGD

1. Upper GI Bleeding (Most Important)

• Injection: Adrenaline (1:10,000) - most widely used; 4-quadrant injection around vessel; causes vasoconstriction and tamponade
• Thermal coagulation: Heater probe (contact), argon plasma coagulation (APC - non-contact), bipolar electrocoagulation (BICAP)
• Mechanical: Hemoclips (Resolution clips, Over-the-scope clips/OTSC) - best for actively bleeding vessels, best for Dieulafoy lesion
• Combination therapy: Injection + thermal/mechanical - superior to monotherapy (Cochrane evidence)
• Hemostatic powder (TC-325/Hemospray): Newer; useful for diffuse bleeding, not suitable for definitive therapy of arterial bleeders

• Oesophageal varices: Endoscopic variceal ligation (EVL/banding) - gold standard; 6-10 bands applied; superior to sclerotherapy
• Gastric varices: Endoscopic injection with cyanoacrylate glue (N-butyl-2-cyanoacrylate, Histoacryl) - standard; TIPS if refractory
• Endoscopic sclerotherapy (ES): Injection of sclerosant (ethanolamine, STD) into varix; older technique; more complications than EVL

---

2. Achalasia / Dysphagia

• Pneumatic balloon dilation: 30-40 mm balloon across gastro-oesophageal junction; 60-85% success; risk of perforation (3-5%)
• Per-oral endoscopic myotomy (POEM): Submucosal tunnel created from mid-oesophagus to gastric cardia; myotomy of inner circular muscle layer; excellent results (>90% success); no external scar; risk of reflux

---

3. Oesophageal/Gastric/Duodenal Strictures and Obstruction

• Savary-Gilliard dilators: Wire-guided polyvinyl bougies (7 to 20 mm); tapered tip; for oesophageal strictures
• Maloney/Hurst bougies: Blind mercury-weighted dilators; for simple web strictures
• TTS (through-the-scope) balloons: Inflated under direct vision; for pyloric and anastomotic strictures
• Rule of 3: Never dilate more than 3 bougie sizes (3 mm) per session

• Self-expanding metallic stents (SEMS): Fully covered (FCSEMS), partially covered, uncovered
• For malignant oesophageal/gastric outlet obstruction, palliation
• Also used for oesophageal leaks/perforations (covered stents)
• Self-expanding plastic stents (SEPS): Removable; for benign strictures

---

4. Polypectomy

• Snare polypectomy: Electrocautery snare around polyp stalk; for pedunculated polyps
• Endoscopic mucosal resection (EMR): Saline injection to lift mucosa, snare removal; for sessile polyps/flat lesions up to 20 mm
• Endoscopic submucosal dissection (ESD): Submucosal injection + specialized knife dissection; en bloc resection of lesions >20 mm; higher technical difficulty, risk of perforation

---

5. Percutaneous Endoscopic Gastrostomy (PEG)

1. Endoscope in stomach; transilluminate anterior gastric wall
2. External site chosen (epigastric, 2-3 cm below costal margin, left of midline)
3. Digital indentation confirmed endoscopically
4. Needle inserted through abdominal wall into stomach under vision
5. Wire passed through needle, grabbed by snare endoscopically
6. Wire pulled out through mouth
7. PEG tube attached to wire, pulled through mouth and through abdominal wall (pull technique)
8. Internal bumper (mushroom) holds tube in stomach
9. External bumper fixed 0.5-1 cm from skin

---

6. Foreign Body Removal

• Coins, food bolus, button batteries (emergency - cause electrochemical burns)
• Rat-tooth forceps, Roth net, snare, overtubes (for sharp objects)
• Button batteries: emergency OGD within 2 hours

7. Enteral Stenting / Duodenal Stenting

• For gastric outlet obstruction (GOO) from malignancy
• SEMS placed endoscopically ± fluoroscopic guidance
• 80-90% technical success

8. Hemostasis for Mallory-Weiss Tear

• Hemoclips or injection therapy

---

Q.4 Short Answer Questions (20 Marks)

Q.4(a) Procedures for Morbid Obesity - Bariatric Surgery (10 Marks)

Definitions

• Obesity: BMI ≥30 kg/m²
• Morbid obesity (Class III): BMI ≥40 kg/m² (or ≥35 with obesity-related comorbidities)

Indications for Bariatric Surgery (NIH 1991 Consensus)

1. BMI ≥40 kg/m², OR
2. BMI 35-40 kg/m² + at least one obesity-related comorbidity (T2DM, hypertension, OSA, non-alcoholic fatty liver disease, etc.)
3. ASMBS 2022 update: considers BMI ≥35 without comorbidities; BMI 30-35 if T2DM (especially Asian populations)
4. Failed non-surgical weight loss attempts
5. Age 18-65 (extended on case-by-case basis)
6. Psychologically stable, motivated, no active substance abuse

Classification of Bariatric Procedures

---

A. Laparoscopic Sleeve Gastrectomy (LSG) - Most Commonly Performed Worldwide

1. Laparoscopic approach, 5 ports
2. Greater omentum mobilized from greater curvature
3. Hiatal dissection to expose angle of His
4. 36-42 Fr bougie placed in stomach to calibrate
5. Linear staplers (GIA/Endo-GIA) fired along bougie from antrum to angle of His
6. Sleeve-shaped stomach (approx 100-150 mL capacity)
7. ~80% of gastric volume removed
8. Buttressing of staple line optional

---

B. Roux-en-Y Gastric Bypass (RYGB) - Gold Standard

1. Small gastric pouch created (~30 mL) - stapler across proximal stomach
2. Roux limb: Jejunum divided 30-50 cm from Treitz ligament
3. Alimentary (Roux) limb: 75-150 cm brought up to pouch (antecolic/retrocolic)
4. Gastrojejunostomy (pouch to Roux limb) - circular or linear stapler / hand-sewn
5. Biliopancreatic limb: carries bile and pancreatic juice
6. Jejunojejunostomy at 75-150 cm from gastrojejunostomy
7. Mesenteric defects closed to prevent internal herniation

---

C. Biliopancreatic Diversion with Duodenal Switch (BPD-DS)

1. Sleeve gastrectomy (restrictive component)
2. Duodenum transected 2 cm beyond pylorus
3. Ileum divided 250 cm from ileocecal valve - this is the alimentary (food) limb
4. Duodenoileostomy: duodenal stump anastomosed to alimentary limb
5. Common channel: 75-100 cm (where bile + food mix, absorption occurs)
6. Biliopancreatic limb carries bile to common channel

---

D. Laparoscopic Adjustable Gastric Band (LAGB)

1. Silicone band placed around upper stomach (pars flaccida technique)
2. Buckle mechanism creates a small gastric pouch (~30 mL) above band
3. Subcutaneous port connected to band via tubing
4. Band tightened/loosened by injecting saline into port

---

E. Endoscopic Procedures (Emerging/Non-surgical)

1. Intragastric Balloon (IGB):
   • Orbera balloon (fluid-filled, 400-700 mL) placed endoscopically, removed at 6 months
   • Average weight loss: 10-15 kg
   • For BMI 30-40 or pre-operative weight loss in super-obese
2. Endoscopic Sleeve Gastroplasty (ESG):
   • Endoscopic suturing (OverStitch) to plicate gastric body
   • Reduces gastric volume by ~70%
   • ~15-20% total body weight loss
3. Aspiration Therapy (AspireAssist): Gastric tube with external valve for aspiration of gastric contents 20 minutes post-meal; controversial

---

Metabolic Effects of Bariatric Surgery

• T2DM remission: 70-80% after RYGB; 55-65% after LSG
• Hypertension resolution: ~60%
• OSA resolution: ~80%
• Dyslipidemia improvement: >70%
• NAFLD improvement
• Reduction in mortality: 30-40% reduction in long-term all-cause mortality (Swedish Obese Subjects study)

---

Complications of Bariatric Surgery

• DVT/PE (prophylaxis: LMWH + compression stockings + early mobilization)
• Wound infection, port site hernia

• Staple line leak (1-3%) - most serious; treat with covered stent or re-exploration
• Sleeve stenosis
• GERD exacerbation

• Anastomotic leak (1-2%) - early; anastomotic stricture (5%) - late
• Dumping syndrome (early: osmotic; late: hypoglycaemia)
• Marginal ulcer (smoking, NSAID use)
• Internal hernia (2-5%) - after laparoscopic RYGB
• Nutritional deficiencies: B12, iron, folate, calcium, thiamine

---

Q.4(b) Blood Products and Blood Substitutes (10 Marks)

Blood Products

• 450-500 mL per unit (+ anticoagulant = 510-537 mL total)
• Rarely used routinely; used in massive transfusion, damage control resuscitation
• Contains all components; increasing evidence for use in major hemorrhage (particularly military, trauma)

---

1. Packed Red Blood Cells (PRBC / Packed Cells)

• Preparation: Whole blood centrifuged; plasma removed; RBC suspended in additive solution (SAG-M: saline, adenine, glucose, mannitol)
• Volume: 250-350 mL per unit
• Storage: 4°C for 35-42 days
• Hematocrit: ~55-65%
• Indication: Symptomatic anaemia, acute blood loss (Hb trigger: <7 g/dL in most patients; <8 g/dL in cardiac patients); restrictive transfusion strategy (TRICC trial)
• Expected rise: Each unit raises Hb by ~1 g/dL, Hct by ~3%

2. Fresh Frozen Plasma (FFP)

• Preparation: Plasma separated and frozen within 6-8 hours of collection; contains all coagulation factors including labile factors V and VIII
• Volume: 200-300 mL per unit
• Storage: -30°C for 12 months; once thawed, use within 24 hours
• Indications:
  • Replacement of multiple coagulation factor deficiencies (DIC, liver disease, massive transfusion)
  • TTP (thrombotic thrombocytopenic purpura) - large volume plasma exchange
  • Warfarin reversal (if Vit K takes too long; now largely replaced by PCC)
  • Dilutional coagulopathy after massive transfusion
• Dose: 10-15 mL/kg (4 units typically)
• Targets: INR <1.5, APTT ratio <1.5

3. Platelets

• Types:
  • Random Donor Platelets (RDP): 4-6 units pooled = 1 adult dose
  • Single Donor (Apheresis) Platelets: from one donor by platelet apheresis = 1 adult dose
• Storage: 20-24°C on agitator for 5-7 days (room temperature - short shelf life)
• Volume: 200-300 mL per adult dose
• Indications:
  • Active bleeding + platelets <50 × 10⁹/L
  • Prophylactic: platelets <10 × 10⁹/L in stable patients; <20 × 10⁹/L if febrile/infected
  • Pre-procedure: platelets <50 × 10⁹/L (surgery, LP); <100 × 10⁹/L (neurosurgery/ophthalmic)
  • Platelet dysfunction (qualitative defect) with active bleeding
• Expected rise: Each RDP unit raises count by 5-10 × 10⁹/L; apheresis unit raises by 20-40 × 10⁹/L

4. Cryoprecipitate

• Preparation: Cold precipitation of FFP at 1-6°C; thawed FFP centrifuged, precipitate retained
• Volume: 10-20 mL per unit; usually given as pooled (6-10 units)
• Contains: Fibrinogen (150-300 mg/unit), factor VIII (80-100 IU/unit), von Willebrand factor (vWF), factor XIII, fibronectin
• Indications:
  • Hypofibrinogenaemia (fibrinogen <1.5 g/L in bleeding patient; <1.0 g/L trigger)
  • Haemophilia A (factor VIII deficiency) - if no specific concentrate available
  • Von Willebrand disease (if DDAVP fails and no vWF concentrate available)
  • DIC with low fibrinogen
  • Massive transfusion
• Dose: 1.5-2.0 pools; 1 unit per 5-10 kg body weight

5. Factor Concentrates

• Factor VIII concentrate: Haemophilia A
• Factor IX concentrate: Haemophilia B (Christmas disease)
• Prothrombin Complex Concentrates (PCC - Beriplex, Octaplex): Contains factors II, VII, IX, X + protein C and S; for urgent warfarin reversal, liver disease, hemorrhage; faster and more effective than FFP
• Recombinant Factor VIIa (NovoSeven): Unlicensed use in refractory surgical/trauma hemorrhage
• von Willebrand Factor concentrate: von Willebrand disease
• Fibrinogen concentrate (RiaSTAP): Hypofibrinogenaemia; increasingly preferred over cryoprecipitate

6. Albumin

• 4.5% or 5% (iso-oncotic) and 20-25% (hyperoncotic)
• Indications:
  • Spontaneous bacterial peritonitis (SBP) - 1.5 g/kg on day 1, 1 g/kg on day 3 (reduces hepatorenal syndrome)
  • Therapeutic large-volume paracentesis (>5L) - 6-8 g per liter drained
  • Hepatorenal syndrome
  • Ovarian hyperstimulation syndrome

7. Intravenous Immunoglobulin (IVIg)

• Prepared from pooled human plasma (thousands of donors)
• For immune thrombocytopenic purpura (ITP), Kawasaki disease, primary immunodeficiencies, Guillain-Barré syndrome

8. Granulocytes

• Rarely used; severe neutropenia with life-threatening bacterial/fungal infection refractory to antibiotics

---

Blood Substitutes (Oxygen Therapeutics)

A. Haemoglobin-Based Oxygen Carriers (HBOCs)

• Polymerized hemoglobin (PolyHeme, Hemopure/HBOC-201): Cross-linked, polymerized bovine or human Hb
• Mechanism: Carry and release O₂ independent of red cells
• Advantages: Long shelf life, no cross-matching needed, no blood-borne disease risk
• Disadvantages: Vasoconstriction (scavenges NO), hypertension, cardiac events; clinical trials largely unsuccessful; HBOC-201 approved in South Africa for compassionate use (Jehovah's Witnesses, rural hospitals, massive hemorrhage)

B. Perfluorocarbon Compounds (PFCs)

• Oxygent (perflubron emulsion), Fluosol
• Mechanism: Dissolve O₂ physically (not chemically); O₂ delivery proportional to partial pressure
• Require high FiO₂ (100% O₂) to be effective
• Advantages: No cross-matching, stable, no infection risk
• Disadvantages: Require 100% O₂, short circulatory half-life (12-24 hours), flu-like syndrome, thrombocytopenia
• Current status: None FDA-approved; ongoing research

C. Cell-Free Hemoglobin (Stroma-free Hb)

• Pure hemoglobin without red cell membrane
• Problem: short half-life (2-4 hours), nephrotoxicity, vasoconstriction
• Conjugated/PEGylated forms in development

D. Recombinant Hemoglobin

• Genetically engineered Hb; potential to modify O₂ affinity
• Still experimental

---

Complications of Blood Transfusion

• Acute hemolytic reaction (ABO incompatibility - most lethal; human error)
• Delayed hemolytic reaction (Kidd/Duffy antigens; 5-14 days post)
• Febrile non-hemolytic reaction (anti-WBC antibodies against donor WBCs)
• Allergic/anaphylactic reaction (IgA-deficient recipient)
• Transfusion-related acute lung injury (TRALI) - leading cause of transfusion death; anti-HLA antibodies
• Graft-versus-host disease (GvHD) - immunocompromised patients; prevented by irradiated blood
• Post-transfusion purpura

• Hepatitis B (1:200,000), Hepatitis C (1:1,000,000), HIV (1:2,000,000) - modern risk per unit
• CMV, EBV, HTLV-I/II, West Nile virus
• Bacterial contamination (platelets - most common; gram-negative organisms)
• Prions (variant CJD) - theoretical

• Transfusion-associated circulatory overload (TACO)
• Hypothermia (rapid transfusion)
• Hyperkalaemia, hypocalcaemia, metabolic acidosis (massive transfusion)
• Iron overload (multiple transfusions)
• Dilutional coagulopathy (massive transfusion)

---

Summary of Marks Distribution

---

MS General Surgery Year-1 - September 2025 (Set 2)

Detailed Answers - Standard Textbook

---

Q.1 Anatomy of Veins of Lower Limb + Physiology of Venous Blood Flow + Varicose Veins (30 Marks)

PART A: Anatomy of Veins of Lower Limb

1. Superficial Venous System

• Longest vein in the body
• Origin: medial end of dorsal venous arch of foot
• Passes anterior to medial malleolus
• Ascends along medial aspect of leg and thigh
• Passes through the saphenous opening (oval fossa) in the deep fascia
• Saphenofemoral Junction (SFJ): Drains into the femoral vein at the groin, 3.5 cm below and lateral to pubic tubercle
• Tributaries at SFJ (6 "friends" of the GSV):
  • Superficial epigastric vein
  • Superficial circumflex iliac vein
  • Superficial external pudendal vein
  • Deep external pudendal vein
  • Anterolateral thigh vein
  • Posteromedial thigh vein
• Valves: 7-12; most important ones at SFJ (terminal and pre-terminal valves) and proximal thigh

• Origin: lateral end of dorsal venous arch
• Passes posterior to lateral malleolus
• Ascends in the midline of the posterior calf
• Pierces the deep fascia in the popliteal fossa
• Saphenopopliteal Junction (SPJ): Drains into the popliteal vein (variable junction level - often at or above popliteal crease); level must be confirmed by duplex before surgery

• SSV may have a cranial extension (vein of Giacomini) that connects to the GSV in the thigh

2. Deep Venous System

• Posterior tibial veins (2 paired) - most important for calf pump mechanism
• Anterior tibial veins (2 paired)
• Peroneal veins (2 paired)
• These three paired veins join to form the popliteal vein behind the knee
• Popliteal vein becomes femoral vein (previously "superficial femoral vein" - misnomer as it is part of the deep system)
• Profunda femoris (deep femoral) vein joins femoral vein in upper thigh
• Becomes common femoral vein below inguinal ligament
• Continues as external iliac vein → common iliac vein → inferior vena cava

3. Perforating Veins (Communicating Veins)

4. Venous Drainage of the Foot

• Plantar venous plexus (sole of foot) - important for calf pump
• Dorsal venous arch of foot - origin of both saphenous veins
• Digital veins drain into metatarsal veins → dorsal arch

---

PART B: Physiology of Venous Blood Flow in Lower Limb

Mechanisms of Venous Return (Against Gravity)

• Contraction of gastrocnemius and soleus muscles compresses deep veins (especially posterior tibial and peroneal sinuses)
• Generates pressure of 200-300 mmHg
• Drives blood proximally toward heart; valves prevent reflux
• 60-70% of venous return from lower limb dependent on this pump
• Walking reduces ambulatory venous pressure from ~90 mmHg to ~25 mmHg

• Bicuspid semilunar valves; more numerous in distal veins
• Prevent gravitational reflux of blood
• In the lower limb: ~6-9 valves in the GSV; 3-5 in the femoral vein; 1-2 in iliac veins
• Destruction/incompetence → venous hypertension

• Inspiration: intrathoracic pressure falls → right atrial pressure falls → venous return increases
• Abdominal compression on expiration helps

• Residual arterial pressure from arterial system drives venous return

• Negative intrathoracic pressure in diastole

• Adjacent artery pulsations transmit to veins (especially in close proximity)

• Standing increases venous pressure → arteriolar constriction (local reflex) → limits capillary filtration

Venous Pressure in Lower Limb

• At rest standing: ankle venous pressure ~90 mmHg (hydrostatic column)
• Normal walking: reduces to 25-30 mmHg (calf pump effective)
• In CVI (chronic venous insufficiency): fails to fall below 50-60 mmHg during walking (ambulatory venous hypertension)

Starling's Forces at Capillary Level

• Capillary hydrostatic pressure drives filtration out
• Plasma oncotic pressure draws fluid in
• Venous hypertension raises capillary hydrostatic pressure → oedema, skin changes

---

PART C: Varicose Veins

Definition

---

Etiology

1. Female sex (estrogen and progesterone weaken vein wall)
2. Pregnancy (increased venous pressure, hormonal effects) - most common cause in women
3. Prolonged standing (occupational - nurses, teachers, hairdressers)
4. Obesity (increased intraabdominal pressure impairs venous return)
5. Family history (autosomal dominant tendency - up to 40% have first-degree relative affected)
6. Age (progressive valve degeneration)
7. Previous DVT (post-thrombotic syndrome)
8. Constipation (raised intraabdominal pressure)
9. Pelvic tumors (compressing iliac veins)

• Deep vein thrombosis → valvular destruction → deep venous reflux → perforator incompetence → secondary superficial varicosities (post-thrombotic syndrome)
• AV malformations / fistulae (Klippel-Trenaunay syndrome)
• Pelvic tumors / pregnancy compressing iliac veins

• C0: No visible disease
• C1: Telangiectasia / reticular veins
• C2: Varicose veins
• C3: Oedema
• C4a: Pigmentation / eczema
• C4b: Lipodermatosclerosis / atrophie blanche
• C5: Healed venous ulcer
• C6: Active venous ulcer

---

Clinical Presentation

• Visible dilated, tortuous subcutaneous veins (most common presenting complaint)
• Aching/heaviness in legs (worse on prolonged standing, better with elevation)
• Pruritus over varicosities
• Ankle swelling (pitting oedema) at end of day
• Restless legs, cramps
• Cosmetic concern

• Visible varicosities (distribution follows GSV or SSV territory)
• Ankle oedema
• Haemosiderin pigmentation (medial gaiter area - iron deposition from red cell extravasation)
• Lipodermatosclerosis (indurated, fibrotic skin - chronic phase)
• Venous eczema (varicose eczema)
• Atrophie blanche (white atrophic scarring - hallmark of severe CVI)
• Venous ulceration (gaiter area - medial malleolus: venous; lateral malleolus: arterial)
• Corona phlebectatica (intradermal veins at ankle - early sign of CVI)

• Trendelenburg test (tourniquet test): Elevates leg to empty veins; tourniquet applied above knee; on standing - if veins fill from below = perforator incompetence; if fill rapidly when tourniquet released = SFJ incompetence
• Perthes' test: Tourniquet applied to mid-thigh; patient walks; if varices decrease = deep vein patent; if varices increase = deep vein obstruction (surgery contraindicated)
• Fegan's test: Identify perforator sites - fascial defect palpable with finger along line of varices
• Morrissey's cough impulse: Cough impulse palpable at SFJ on coughing confirms incompetence
• Schwartz's tap test: Tap lower vein - fluid thrill palpable above (confirms continuity)

• Duplex ultrasound (Doppler): Gold standard - identifies site(s) of reflux, maps GSV/SSV diameter and course, assesses deep venous system patency, identifies perforator incompetence. Venous reflux defined as retrograde flow >0.5 sec after Valsalva/compression release
• Venography (ascending phlebography): Now rarely used; still gold standard for deep vein anatomy if duplex inadequate
• CT/MR venography: For complex/recurrent cases; pelvic veins assessment

---

Complications of Varicose Veins (BHETHAD)

1. Bleeding - spontaneous rupture of varix (especially at ankle); elevated by limb elevation; can be torrential and underestimated
2. Haemorrhage / Haematoma - after minor trauma
3. Eczema - varicose/stasis eczema
4. Thrombophlebitis (superficial venous thrombosis - SVT) - painful cord-like induration; risk of propagation to deep veins (up to 25%)
5. Hyperpigmentation - haemosiderin deposition
6. Atrophie blanche - white atrophic patches
7. Deep vein thrombosis - from SVT extension or stasis
8. Lipodermatosclerosis - progressive fibrosis of skin and subcutaneous tissue
9. Ulceration - venous ulcer; medial gaiter area; associated with sustained ambulatory venous hypertension
10. Calcification - phleboliths (calcified thrombi in varicosities)

---

Management

Conservative Management

1. Elevation of legs when resting
2. Exercise (calf pump activation - walking)
3. Compression hosiery: Class I (14-17 mmHg): mild; Class II (18-24 mmHg): moderate; Class III (25-35 mmHg): severe
   • Indicated for: pregnancy-related varicosities, mild symptoms, comorbidities precluding intervention
4. Weight loss
5. Skin care: emollients, topical steroids for eczema, regular moisturizing

Endovenous / Interventional Management (First Line for Most Patients)

• Most widely used; NICE recommended
• Laser fiber (810, 940, 980, 1470 nm) introduced via needle puncture; tip positioned 2 cm from SFJ (confirmed by duplex)
• Tumescent anesthesia injected around vein (thermal protection + analgesia)
• Laser activated as fiber withdrawn - thermal injury destroys venous endothelium
• Vein fibroses and shrinks
• Daycase procedure; >95% technical success; QoL equivalent to surgery

• 7 cm segmental catheter delivers radiofrequency energy at 120°C
• Causes collagen contraction and vein occlusion
• Multiple 20-second treatment cycles
• Less post-operative bruising and pain compared to EVLA
• VNUS Closure system; 5-year occlusion rate >85%

• Sclerosant (polidocanol or sodium tetradecyl sulfate) agitated with air/CO₂ to form foam (Tessari technique)
• Foam displaces blood in varix; concentrated contact with endothelium → chemical injury → fibrosis
• Can treat tortuous varicosities not amenable to thermal ablation
• Cheaper; suitable for recurrent varicosities
• Foam:liquid ratio 4:1; max 10-12 mL foam per session
• Higher recurrence than thermal ablation

• Medical grade glue injected via catheter; seals vein shut; no tumescence needed
• No thermal risk; can return to normal activity immediately
• Good medium-term results; foreign body reactions reported

• Rotating wire causes mechanical endothelial damage + simultaneous sclerosant infusion
• No tumescent anesthesia needed; no thermal risk; daycase

Surgical Management

1. Groin incision (upper groin crease), 4-5 cm oblique or transverse
2. GSV identified medial to femoral vein
3. All tributaries at SFJ ligated and divided flush (to prevent recurrence - neovascularization at groin the main cause of recurrence)
4. SFJ ligated flush with femoral vein (must not narrow femoral vein)
5. Long saphenous vein stripped (intraluminal stripper - Myers/PIN stripper) from groin to just below knee (not to ankle - risk of saphenous nerve injury)
6. Avulsions (phlebectomies): Multiple stab incisions (2-3 mm), tributaries hooked out with Oesch hooks or mosquito forceps; no sutures needed (cosmetically excellent result)
7. Compression bandaging applied

• Subfascial endoscopic perforator surgery (SEPS): Endoscopic clips/division of incompetent perforators under tourniquet; for recurrent venous ulcers
• Saphenopopliteal junction (SPJ) ligation: For SSV-territory varicosities; SPJ identified by duplex marking; through popliteal fossa incision
• Foam sclerotherapy for residual varicosities post-operatively

---

Management of Complications

---

Q.2 Surgical Anatomy of Liver + Functions + Life Cycle of E. granulosus + Hydatid Cyst of Liver (30 Marks)

PART A: Surgical Anatomy of the Liver

External Features

• Largest solid organ (1200-1500 g; 2% of body weight)
• Right hypochondrium + epigastrium
• Protected by lower ribs (right 5th to 11th)
• Two surfaces: diaphragmatic (convex, anterior + superior) and visceral (inferior, posterior)
• Bare area: Posterior surface not covered by peritoneum; directly contacts diaphragm; bounded by anterior and posterior reflections of coronary ligament

Ligaments

Lobar Anatomy (Morphological/Classical)

• Right lobe: Separated from left by falciform ligament (classical - not functional)
• Left lobe: Quadrate lobe + left lobe proper
• Quadrate lobe: Inferior surface, between gallbladder fossa and round ligament; functionally left lobe (segment IV)
• Caudate lobe (Spiegelian lobe): Posterior surface; receives blood from both right and left portal branches; drains directly into IVC by caudate hepatic veins; not included in classical right/left division

Couinaud's Segmental Anatomy (Functional - Surgically Important)

• Segment I: Caudate lobe (posterior, independent blood supply)
• Segments II, III: Left lateral section (left of falciform)
• Segment IV (IVa, IVb): Left medial section (quadrate lobe area)
• Segments V, VI: Right posterior-inferior section
• Segments VII, VIII: Right posterior-superior section

Blood Supply

• Hepatic artery proper (from common hepatic artery, branch of coeliac axis)
• Divides into right and left hepatic arteries at the porta hepatis
• Supplies ~25% of hepatic blood flow; 50% of O₂ delivery
• Cystic artery (usually from right hepatic artery) to gallbladder

• Replaced right hepatic artery from SMA (~18%)
• Replaced left hepatic artery from left gastric artery (~15%)
• Both replaced (~4%)

• Forms behind neck of pancreas by union of superior mesenteric vein + splenic vein
• Supplies ~75% of hepatic blood flow; 50% of O₂ delivery
• Normal pressure: 7-12 mmHg
• Portal hypertension: >12 mmHg
• At porta hepatis: divides into right and left portal veins

• Right, middle, left hepatic veins → IVC
• Several small caudate veins directly to IVC
• Hepatic venous pressure gradient (HVPG): Normal <5 mmHg; clinically significant portal hypertension >10 mmHg; varices form when >12 mmHg

Biliary System

• Right and left hepatic ducts → Common hepatic duct (joined by cystic duct) → Common bile duct (CBD)
• CBD enters 2nd part of duodenum at ampulla of Vater (with main pancreatic duct)
• CBD diameter: <6 mm normal (up to 10 mm post-cholecystectomy)
• Calot's triangle: (Hepatocystic triangle) - bounded by cystic duct (below), common hepatic duct (medially), cystic artery (above); critical area in cholecystectomy

Lymphatics

• Superficial: drain to hepatic nodes in porta hepatis → celiac nodes → cisterna chyli
• Deep: follow portal tracts; drain to hepatic nodes
• Important: Liver is the main site of lacteals from the small intestine (chylous lymph)

Nerve Supply

• Sympathetic: T7-T10 (via celiac plexus)
• Parasympathetic: right vagus nerve (posterior trunk)
• Pain fibers: hepatic capsule (Glisson's capsule) and diaphragmatic peritoneum over liver → referred to right shoulder tip (phrenic nerve, C3-5)

Porta Hepatis

• "Gateway of the liver" - transverse fissure on inferior surface
• Contains: portal vein (posterior), hepatic artery (left/anterior), bile duct (right/anterior), lymphatics, nerve plexus
• Pringle's manoeuvre: Digital compression/clamping of hepatoduodenal ligament to control hepatic inflow; tolerated for up to 15-20 min at normothermia (longer with intermittent clamping)

---

PART B: Functions of the Liver (Enumerate)

1. Carbohydrate metabolism - glycogenesis, glycogenolysis, gluconeogenesis (maintains blood glucose)
2. Protein metabolism - synthesis of albumin (main), fibrinogen, prothrombin, coagulation factors (II, V, VII, IX, X, XI), complement proteins; deamination of amino acids; urea synthesis (urea cycle)
3. Lipid metabolism - fatty acid oxidation, lipogenesis, synthesis of cholesterol and phospholipids, production of VLDL, HDL; ketogenesis
4. Synthesis of bile acids and bile salts (from cholesterol)

---

PART C: Life Cycle of Echinococcus granulosus

Taxonomy

• Phylum: Platyhelminthes
• Class: Cestoda (tapeworm)
• Order: Cyclophyllidea
• Family: Taeniidae
• Genus/Species: Echinococcus granulosus (cystic hydatid disease) and E. multilocularis (alveolar hydatid disease)

The Two-Host Life Cycle

Life Cycle Steps:

• Adult tapeworm (E. granulosus) lives in small intestine of dog
• Small worm: 3-6 mm long; scolex + 3-4 proglottids (immature, mature, gravid)
• Gravid proglottids passed in dog feces → soil/pasture contamination
• Each gravid proglottid contains ~500-800 hexacanth embryos (oncospheres)
• Eggs are very resistant: survive 2 years in favorable conditions

• Eggs ingested by sheep/cattle/humans from contaminated soil, water, vegetables, dog fur
• In humans: feco-oral transmission; direct contact with infected dogs (licking hands/face)
• Highest prevalence: Sheep-rearing communities (Mediterranean, Middle East, Central Asia, Sub-Saharan Africa, South America, Australia)

• Eggs hatch in duodenum → hexacanth embryos (oncospheres) released
• Penetrate intestinal mucosa → enter portal circulation
• Liver is the first filter (most common site - 70%); lungs second (20%); any organ possible
• Oncosphere → protoscolex forms → hydatid cyst develops
• Cyst growth: 1-3 cm per year; may reach very large size (liters)
• Cyst structure:
  • Pericyst (ectocyst/host-derived layer): Outer fibrous layer formed by host reaction; may calcify (dead cyst sign)
  • Ectocyst (laminated membrane): Outer parasite-derived, laminated, white, pearly, acellular layer; "egg shell" like
  • Endocyst (germinal layer): Inner cellular layer (germinal epithelium); gives rise to brood capsules, daughter cysts, scolices, hydatid sand, laminated membrane
  • Hydatid fluid: Clear, "spring water" appearance; contains scolices, daughter vesicles, free scolices ("hydatid sand"); highly allergenic - anaphylaxis if spilled
  • Brood capsules: Bud from germinal layer; contain protoscolices (future tapeworm heads)
  • Daughter cysts: Secondary cysts formed inside primary cyst

• When definitive host (dog) ingests infected viscera of intermediate host (sheep with hydatid cyst)
• Protoscolices (tapeworm heads) are released in dog's small intestine
• Each protoscolex develops into an adult tapeworm in 6-8 weeks
• Cycle repeats

WHO Classification of Cyst Stages (for management decisions):

• CE1: Active, unilocular, anechoic
• CE2: Active, multivesicular, "honeycomb"
• CE3a: Transitional, detached laminated membrane ("water lily sign")
• CE3b: Transitional, daughter cysts in solid matrix
• CE4: Inactive, heterogeneous, no daughter cysts
• CE5: Inactive, calcified

---

PART D: Clinical Presentation, Management, and Complications of Hydatid Cyst of Liver

Clinical Presentation

• Long asymptomatic period (most common presentation - incidental finding on imaging)
• Hepatomegaly / abdominal mass - right upper quadrant, smooth, non-tender, rounded mass
• RUQ aching / pain - from capsule distension
• Nausea, vomiting - pressure on stomach
• Jaundice - biliary communication / compression of bile ducts
• Urticaria / allergic symptoms - from cyst fluid leakage
• Fever, rigors - secondary infection of cyst
• Anaphylaxis - from sudden cyst rupture (life-threatening)
• Dyspnea - if large cyst compresses diaphragm / if pulmonary involvement

• Smooth, rounded, cystic mass in right hypochondrium
• "Hydatid thrill" - palpable fluid thrill in large cysts (Leriche's sign - historical)
• Hepatomegaly
• Signs of jaundice if biliary communication
• Signs of secondary infection if superinfected

Investigations

1. Ultrasound (USG) - first line:
   • Anechoic cyst with well-defined wall (CE1)
   • Daughter cysts ("honeycomb/rosette" pattern) - pathognomonic
   • Floating membrane ("water lily sign" - CE3a - detached endocyst)
   • Calcified wall (CE4/CE5 - dead cyst)
   • Gharbi classification (older: types I-V)
   • Sensitivity: 93-95%
2. CT scan - best for:
   • Defining cyst anatomy, relationship to vasculature/biliary tree
   • Detects daughter cysts, calcification, biliary communication
   • Pre-operative planning
   • Shows hypodense cyst with calcified rim
3. MRI:
   • Best for biliary communication assessment
   • MRCP for biliary anatomy
   • Does not use radiation
4. CXR: May show elevated right hemidiaphragm; lung cysts

• Casoni skin test (intradermal injection of hydatid antigen): Now largely obsolete
• Weinberg (complement fixation) test: Obsolete
• ELISA for anti-Echinococcus antibodies: Sensitivity 80-95%; specificity 88-96%; test of choice
• Indirect hemagglutination test (IHAT): Sensitivity ~90%
• Western blot for Arc-5 band: Confirmatory; highly specific
• Eosinophilia: Present in ~20-30% (unreliable)
• LFTs: Raised if biliary communication/secondary infection; elevated bilirubin
• FBC: Eosinophilia may be present
• Note: Fine-needle aspiration/biopsy is CONTRAINDICATED (risk of anaphylaxis and peritoneal seeding)

Management

Medical Management

• Albendazole (preferred): 400 mg BD (10-15 mg/kg/day) in 28-day cycles with 14-day drug-free intervals
• Mebendazole: Less well absorbed; alternative
• Indications: Multiple cysts, inoperable patients, pre- and post-operatively to prevent recurrence/spillage, small CE1/CE3a cysts
• Response: Cyst may shrink, become avital; CE1→CE4/CE5 transition
• Liver function monitoring required (hepatotoxicity)
• Rarely curative as monotherapy for large cysts

PAIR (Puncture, Aspiration, Injection, Re-aspiration)

1. Puncture: USG-guided needle (16-18 G) into cyst (avoiding bile ducts)
2. Aspiration: Aspirate 1/3 of cyst contents (clear hydatid fluid)
3. Injection: Inject scolicidal agent (20% hypertonic saline or 95% ethanol) - leave for 15-30 min
4. Re-aspiration: Aspirate all contents

• CE1, CE3a cysts <6 cm
• Patients refusing surgery or unfit for surgery
• Not suitable for CE2, CE3b, CE4, CE5, or cysts communicating with bile ducts

Surgical Management

1. Sterilize cyst contents before opening (prevent seeding)
2. Remove all viable parasite tissue
3. Manage residual cavity
4. Address biliary communication

• Pack wound with 20% hypertonic saline-soaked packs (scolicidal)
• Inject 20% hypertonic saline into cyst before opening
• Aspirate cyst contents before opening (trocar and cannula)
• Avoid spillage ("seed-spill-spread")

• Partial pericystectomy + drainage + capitonnage (obliteration of cavity)
• Cyst unroofed; contents removed; cavity irrigated with hypertonic saline; cavity obliterated by suturing walls (capitonnage) or filled with omentum (omentoplasty)
• Cystotomy: Simple opening, removal of endocyst + daughter cysts + hydatid sand

• Total pericystectomy: Complete removal of entire cyst including pericyst without entering cyst - best but technically demanding
• Liver resection: Formal hepatectomy for multiple cysts in one lobe, or when anatomy dictates (associated hepatic disease, malignancy concern)

• Identify biliary opening on internal surface of cyst (bile-staining suggests communication)
• Suture ligation of biliary fistula
• If CBD obstruction from daughter cysts in CBD: ERCP + stone extraction OR surgical CBD exploration + T-tube drainage
• MRCP pre-operatively helpful

• Increasing role for accessible, anterior cysts
• Risk of spillage; controlled with hypertonic saline and PAIR-like aspiration first

---

Complications of Hydatid Cyst of Liver

1. Rupture:
   • Contained rupture: Endocyst detaches but within pericyst (CE3a - water lily sign); may be asymptomatic
   • Communicating rupture: Into biliary tree (most common; 5-25%) → cholangitis, obstructive jaundice, biliary colic, choledocholithiasis (daughter cysts in CBD)
   • Free rupture into peritoneum: Catastrophic; anaphylaxis, peritonitis, secondary peritoneal hydatidosis (multiple seeded cysts)
   • Rupture into pleural space: Pleuropulmonary fistula (if transdiaphragmatic)
2. Secondary infection / Abscess formation: Cyst becomes superinfected (E. coli, Klebsiella); presents as liver abscess; fever, chills, RUQ pain
3. Biliary obstruction: From extrinsic compression OR endocyst rupture into biliary tree with daughter cysts occluding CBD
4. Anaphylaxis: From cyst leakage (spontaneous or iatrogenic)
5. Compression of adjacent structures: IVC obstruction (Budd-Chiari-like), portal hypertension, diaphragmatic elevation
6. Pulmonary involvement: Transdiaphragmatic extension, secondary lung cysts; hemoptysis (if ruptures into bronchus - hydatid vomica)
7. Secondary hydatidosis: Peritoneal seeding after rupture/spillage → multiple peritoneal cysts
8. Bone involvement (rare): From hematogenous spread

---

Q.3 Short Answer Questions (20 Marks)

Q.3(a) Principles, Types, and Hazards of Electrosurgery + Duty of Candour during Mishap (10 Marks)

ELECTROSURGERY (Diathermy)

Principles

• DC or low-frequency AC (<100 Hz): stimulates nerves and muscles (causes shock, VF)
• High-frequency AC (>100 kHz): thermal effect only, no neuromuscular stimulation
• Tissue heated to >60°C: protein denaturation → coagulation
• Tissue heated to >100°C: desiccation/vapourisation → cutting

• Current passes through tissue → resistance in tissue generates heat (Joule heating: Q = I²Rt)
• Current density is the key determinant: high current density = high heat generation
• At active electrode (small): high current density → intense heat → cutting/coagulation
• At return electrode/dispersive pad (large): low current density → minimal heating

• Generator → active electrode → patient → dispersive pad → generator (monopolar)
• Or: Generator → active electrode → tissue → return electrode (bipolar)

---

Types of Electrosurgery

• Continuous sinusoidal waveform at high power
• Active electrode does NOT touch tissue (1-2 mm gap)
• Spark generated → intense local heat → cells vaporize → "cutting"
• Minimal hemostasis (cells vaporize before coagulation)

• Interrupted (pulsed/damped) waveform; 6% duty cycle (on 6% of time)
• Active electrode touches tissue
• Slower heating → protein denaturation → coagulation → hemostasis
• More lateral thermal spread

• Intermediate waveform; cutting + coagulation simultaneously
• Adjustable ratio of cut:coag

• Both electrodes on forceps jaws
• Current passes only between the two jaws (through grasped tissue)
• Minimal spread; no need for dispersive pad
• Safer near vital structures (nerves, vessels); essential in neurosurgery, endoscopy

• Two electrodes form a forceps
• Current flows between jaws; does NOT travel through patient's body
• No dispersive pad needed
• Precise, minimal lateral thermal spread
• Lower power settings (10-30 W)
• Indications: neurosurgery, gynecology, laparoscopy, near implanted devices (pacemakers)
• Disadvantage: cannot be used for cutting; does not work in fluid

1. Harmonic Scalpel (Ultrasonic coagulator - Ethicon Harmonic):
   • Ultrasonic vibration (55,000 Hz) generates friction heat (50-100°C)
   • Seals vessels up to 7 mm, cuts, coagulates simultaneously
   • Less lateral thermal spread (< 3 mm) compared to monopolar
   • No electrical current through patient; safe near pacemakers, neural structures
   • No smoke plume
2. LigaSure (Advanced Bipolar Vessel Sealing - Medtronic):
   • Bipolar energy + pressure → melts collagen and elastin in vessel wall → permanent seal
   • Seals vessels up to 7 mm
   • Feedback-controlled: automatically stops when seal complete
3. Argon Beam Coagulator (APC):
   • Ionized argon gas channels monopolar current to tissue (non-contact)
   • Superficial coagulation; useful for oozing surface (liver, spleen)
4. Tissue Fusion / Plasma Kinetic (PK) devices: Advanced bipolar with impedance feedback

---

Hazards of Electrosurgery

• Dispersive pad site burns (return electrode burns):
  • Incorrect placement (folded, partial contact, dried adhesive)
  • High current density at small contact area → burn
  • Prevention: Full contact over large muscle mass (thigh/buttock); avoid bony prominences, scar tissue, hairy skin
• Alternate site burns:
  • Current seeking low-resistance path; ECG leads, metal implants, earthed metal on table
  • Patient in contact with metal parts of table (poor insulation)
• Direct sparking to non-target tissue:
  • Active electrode left activated accidentally; burns drapes, bowel, other structures

• Sparks during activation; smoke inhalation from plume (viral particles in smoke)

• Low-frequency current component or equipment fault → VF possible
• Modern equipment has isolated circuits and RCCB (residual current circuit breakers)

• Cardiac pacemakers/ICDs: Monopolar current → electromagnetic interference → pacemaker inhibition or inappropriate ICD discharge → bradycardia or VF
• Prevention:
  • Use bipolar diathermy if possible
  • If monopolar needed: active electrode as far from device as possible; dispersive pad on same side; low power short bursts; have defibrillator/pacing equipment ready; pacemaker checked pre/post-operatively
  • Magnet over pacemaker converts to asynchronous mode

• Prevention: Visual inspection of electrodes; use metal trocars with insulated ports; active electrode monitoring (AEM system - Arc Shield)

• Prevention: Use all-metal trocar systems (current dissipates safely to abdominal wall) OR all-plastic trocar systems; never use hybrid (metal + plastic)

• Surgical drapes or bowel gas (if activated in contact with N₂O/methane) can ignite
• Avoid monopolar in presence of flammable anesthetics or near bowel

• Aerosol containing carcinogens (polyaromatic hydrocarbons, cyanides), viable bacteria and viral DNA (HPV, HIV)
• Laparoscopic surgery: smoke insufflated into abdomen
• Prevention: Smoke evacuation systems; N95 masks

• Muscle twitching; risk of ECG interference

---

DUTY OF CANDOUR (Duty of Candour during Surgical Mishap)

Definition

What Constitutes a Notifiable Safety Incident (NSI)?

• Death
• Severe harm (permanent sensory, motor, physiological, psychological impairment)
• Moderate harm (increased length of treatment, increased recovery time)
• Prolonged psychological harm

Obligations Under Duty of Candour

1. Tell the patient (or family if patient incapacitated) - in person; what went wrong and what outcomes may result
2. Apologize sincerely - "I am sorry that this happened to you" - NOT an admission of liability
3. Explain what went wrong in honest, simple terms; what is currently known
4. Explain what actions have been taken to address the situation and what will be done next
5. Offer written record of what was discussed; provide in writing (letter/formal written notification)
6. Offer a meeting to answer further questions; involve senior clinician
7. Inform the patient about support available (patient liaison service, independent advocacy, complaints procedure)

• Full contemporaneous record of incident, disclosure conversation, apology, actions taken
• Incident reporting (Datix/local incident reporting system)
• Serious Incident (SI) reporting to commissioner/NHSE if severe/catastrophic harm

• Provide updates as investigation proceeds; share findings of root cause analysis (RCA)
• Explain what changes will be made to prevent recurrence
• Never pressure patient to sign waiver; never withhold information

Why Candour Matters

• Legal requirement (CQC can prosecute organizations)
• GMC - failure to be candid = fitness to practice concern
• Ethical: respects patient autonomy and right to information
• Evidence: Open disclosure reduces complaints and litigation; improves patient trust
• Francis Report: culture of concealment and non-disclosure was a key factor in Mid Staffs patient harm

Barriers to Candour

• Fear of litigation / blame culture
• Fear of disciplinary action
• Embarrassment
• Uncertainty about what happened (early aftermath)
• Lack of training in disclosure conversations

---

Q.4 Acute Limb Ischemia + Blast Injuries (20 Marks)

Q.4(a) Acute Limb Ischemia (10 Marks)

Definition

---

Etiology

• Cardiac source (80% of emboli):
  • AF with left atrial thrombus (most common) - atrial fibrillation with spontaneous echo contrast
  • Acute MI with mural thrombus (LV thrombus)
  • Infective endocarditis (septic emboli)
  • Prosthetic heart valves
  • Cardiac tumors (atrial myxoma - rare)
• Non-cardiac sources:
  • Aneurysm (popliteal aneurysm most common peripheral aneurysm source of emboli)
  • Aortic atherosclerotic plaque (atheroembolism/"blue toe syndrome")
  • Paradoxical embolism through PFO
  • Iatrogenic (post-interventional - catheter/wire trauma)

• In-situ thrombosis on pre-existing atherosclerotic plaque
• Graft thrombosis (failed bypass graft, prosthetic or vein)
• Stent thrombosis
• Hypercoagulable state (antiphospholipid syndrome, protein C/S deficiency, malignancy)
• Heparin-induced thrombocytopenia (HIT)
• Dissection of aorta/iliac/femoral artery

• Arterial injury from fracture, dislocation (posterior knee dislocation + popliteal artery injury), penetrating trauma, iatrogenic (post-cardiac catheterization femoral artery injury)

• Spontaneous (SCAD extension) or traumatic

• Causing venous occlusion first, then arterial

---

Clinical Features ("6 P's")

1. Pain - sudden, severe (may diminish as nerves become ischemic)
2. Pallor - pale, marble-white initially; later mottled/fixed mottling (bad)
3. Pulselessness - absent distal pulses
4. Paresthesia - numbness, tingling (early neurological ischemia)
5. Paralysis - weakness/inability to move (late, serious sign; indicates profound ischemia)
6. Perishing cold (Poikilothermia) - cold limb; clear demarcation line

• Fixed mottling (purple non-blanching patches) = irreversible ischemia
• Muscle rigidity/tenderness = late sign; myonecrosis begun
• Edema: may indicate reperfusion or venous obstruction

---

Rutherford Classification of ALI

---

Investigations

• Handheld Doppler: Assesses audibility of arterial and venous signals; ABI if time permits
• Duplex ultrasound: Confirms level of occlusion
• CT Angiography: Best for preoperative planning (especially for graft/stent thrombosis); rapid; delineates anatomy
• DSA (Catheter angiography): For intraoperative assessment; also allows simultaneous thrombolysis
• ECG: AF, recent MI
• Echo: LV thrombus, valvular lesions, intracardiac source
• FBC, coagulation, U&E, creatine kinase (CK), lactate, glucose
• Group and save

---

Management

Immediate/Resuscitation

1. IV access, fluid resuscitation
2. IV Heparin immediately (5,000-10,000 IU bolus; then 1000 IU/hr infusion) - prevents thrombus propagation, maintains collateral flow, prevents recurrent embolism
3. Analgesics (IV morphine + antiemetic)
4. Catheterize patient
5. Keep limb at heart level or slightly dependent (not elevated)
6. Padding to protect limb; no warming pads (increases O₂ demand)
7. Mark level of demarcation
8. Urgent vascular surgical referral

Definitive Treatment

1. Local/regional or GA
2. Common femoral artery incision (vertical or oblique): for aortoiliac and femoropopliteal territory
3. Heparin systemically
4. Longitudinal arteriotomy (transverse preferred for small vessels)
5. Fogarty balloon catheter (2F-6F) inserted distally past clot, balloon inflated, catheter withdrawn with gentle steady traction to extract thrombus
6. Repeat proximally for inflow and distally until good pulsatile flow obtained
7. Backflow assessed; brisk backflow = patent distal vessels
8. Papaverine/vasodilators if vasospasm
9. On-table angiogram to confirm complete clot extraction
10. Arteriotomy closed with patch angioplasty (if needed) or primary closure
11. Continue heparin postoperatively → warfarin (INR 2-3 if AF/cardiac source)

• Graft thrombosis
• Thrombosis (in-situ, not embolic)
• Category I and IIa (some IIb if lytic quickly)
• To "uncover" underlying lesion before PTA/stenting

• Recent stroke (<3 months)
• Recent surgery/trauma (<10 days)
• Active internal bleeding
• Severe hypertension
• Category IIb immediately threatened / Category III

• Catheter threaded through clot; thrombolytic infused directly into thrombus over 24-48 hours
• Serial angiograms every 4-8 hours
• Underlying lesion (stenosis, stent) treated by angioplasty/stenting
• TOPAS trial, STILE trial: CDT vs surgery; comparable outcomes for graft thrombosis

• For thrombosis on extensive arterial disease not amenable to embolectomy alone
• Emergency bypass using vein or prosthetic conduit

• Percutaneous mechanical thrombectomy (PMT): Mechanical fragmentation and aspiration of clot
• Rheolytic thrombectomy (AngioJet): High-velocity saline jets fragment/aspirate clot
• Pharmacomechanical thrombolysis: Combined mechanical + CDT

---

Post-Revascularization Complications

• Re-introduction of oxygenated blood to ischemic tissue → reactive oxygen species (ROS) production → inflammation, further tissue damage
• Systemic effects: ARDS, AKI, myocardial depression
• Myoglobinuria → acute tubular necrosis (hydration + mannitol + sodium bicarbonate)
• Hyperkalemia from necrotic muscle release → cardiac arrhythmias

• Post-reperfusion edema → raised intracompartmental pressure (ICP >30 mmHg)
• Compress capillary flow → muscle/nerve ischemia
• 4 compartments of calf: Anterior, lateral, superficial posterior, deep posterior
• Presentation: pain out of proportion, pain on passive stretch, tense compartments
• Treatment: 4-compartment fasciotomy (decompressive; leave wounds open; secondary closure/skin graft after 48-72 hours)
• Prophylactic fasciotomy if: ischemia >6 hours, prolonged intraoperative ischemia

---

Q.4(b) Blast Injuries (10 Marks)

Definition

Physics of an Explosion

1. Detonation: Rapid chemical transformation of explosive compound → huge volume of gas
2. Shock wave (Friedlander wave): Supersonic pressure wave radiates outward; characterized by:
   • Instantaneous peak overpressure (positive phase)
   • Followed by negative pressure (underpressure/suction phase)
3. Blast wind: High-velocity wind following the shock wave (can cause blunt/tertiary injuries)
4. Primary, secondary, tertiary phases of energy release cause different injury patterns

---

Classification of Blast Injuries

---

Primary Blast Injuries

• Occurs at relatively low overpressure (~35 kPa)
• Symptoms: deafness, tinnitus, otalgia, otorrhoea
• Most heal spontaneously; ENT follow-up
• TM rupture is NOT a reliable marker of other blast injuries (recent evidence contradicts older teaching)

• Mechanisms: spalling (disruption at air-liquid interfaces), implosion, shear forces
• Pathology: alveolar capillary rupture, interstitial hemorrhage, pulmonary edema, pneumothorax, hemothorax, air embolism
• Presentation: Progressive hypoxia (may be delayed), hemoptysis, dyspnea, chest pain; may be initially asymptomatic
• CXR: bilateral "butterfly" infiltrates; CT more sensitive (contusions, pneumothoraces)
• Management:
  • High-flow oxygen; ventilatory support if needed
  • Caution with PPV: risk of barotrauma, air embolism (avoid high pressures)
  • Avoid positive pressure if possible; use CPAP/BiPAP first
  • Pneumothorax: intercostal drain
  • Air embolism: head-down/left lateral position; hyperbaric O₂

• Gas-filled bowel susceptible: right colon and small bowel most commonly affected
• Submucosal and subserosal hemorrhage, perforation (immediate or delayed - 24-48 hours)
• Presentation: abdominal pain, peritonism, rectal bleeding; may be delayed
• Diagnosis: CT abdomen (free gas, free fluid, bowel wall thickening)
• Management: Exploration, resection, damage control laparotomy principles

• Globe rupture; vitreous hemorrhage; retinal damage from pressure wave
• Air-filled middle ear involved: ossicular disruption

• Cerebral concussion from shock wave (even without direct head impact)
• "Blast-induced TBI" (traumatic brain injury) - increasing recognition
• Diffuse axonal injury pattern

---

Secondary Blast Injuries

• Fragment/shrapnel wounds: High-velocity metal fragments accelerated by explosion
• Energy follows inverse square law: can cause wounds at much greater distance than primary blast
• Wounds typically irregular, multiple, contaminated, variable depth
• May contain biological material (suicide bombers - contaminated fragments from perpetrator)
• Management: Wound debridement; treat as contaminated wounds; delayed primary closure (DPC); serial debridement; remove fragments only if causing harm (joint space, vascular proximity, infection)
• All fragment wounds presumed contaminated → tetanus prophylaxis, broad-spectrum antibiotics

---

Tertiary Blast Injuries

• Gross body displacement by blast wind; equivalent to severe blunt trauma
• Traumatic amputation - hallmark of close-range blast
• Fractures, crush injuries, organ lacerations
• Blast wind can project victims significant distances
• Management: ATLS principles; damage control surgery
• Blast amputation: High energy; extensive devitalization proximal to apparent level; requires aggressive debridement; "biological amputations" (limbs held only by soft tissue); guillotine amputation + later revision

---

Quaternary and Quinary Injuries

• Burns: Flash burns from thermal phase; clothing on fire; burns to exposed skin
• Crush injuries: From structural collapse
• Inhalation: Hot gas, CO, cyanide, dust inhalation
• Chemical agents: In terrorist incidents, device may incorporate chemical agents
• Radiological contamination ("dirty bomb"): Radiation sickness, contamination
• Biological contamination: Deliberate incorporation of biological agents

---

Principles of Management of Blast Casualties (ATLS)

• Scene safety first (secondary devices)
• Major Incident response: METHANE declaration, START triage
• Tourniquet application for blast amputations (immediate lifesaver)
• Occlusive chest dressing for open chest wounds
• Cervical spine control

• Primary survey (ABCDE)
• Consider ALL blast categories: External wounds may belie internal primary blast injuries
• "Double bubble": If TM ruptured + abdominal signs → high suspicion bowel blast injury
• Chest X-ray, CT chest/abdomen mandatory if significant blast exposure
• Damage Control Resuscitation (DCR):
  • Permissive hypotension (SBP 80-90 in non-TBI)
  • 1:1:1 ratio of PRBC:FFP:Platelets (or whole blood if available)
  • Avoid crystalloid excess
• Damage Control Surgery (DCS): Control hemorrhage, limit contamination; pack and close; ICU; return in 24-48 hours for definitive repair
• Limb injuries: Fasciotomy for vascular injuries; external fixation for fractures; wound excision and DPC

• Secondary devices: Risk of explosion on rescue crews; patient and medical staff decontamination if chemical/radiological
• Psychological effects: Mass casualty events → acute stress disorder, PTSD; psychological first aid

---

Summary Table - Mark Allocation

---

🃏 FLASHCARD SET 1: Couinaud Liver Segments

---

---

---

---

1. Receives portal blood from both right and left portal vein branches
2. Drains directly into the IVC via small caudate veins (not via hepatic veins)
3. Located posteriorly between IVC and porta hepatis

• Clinically: often hypertrophies in Budd-Chiari syndrome; difficult to resect

---

• Located to the left of the falciform ligament
• Segment II = superior/posterior
• Segment III = inferior/anterior
• Resection = left lateral sectionectomy (most common pediatric donor liver procedure)

---

• Located between falciform ligament (left) and Cantlie's line (right)
• Functionally part of the LEFT lobe (despite appearing central)
• Involved in central hepatectomy (segments IV+V+VIII)

---

• Right anterior section: V (inferior) + VIII (superior) — adjacent to gallbladder/IVC
• Right posterior section: VI (inferior) + VII (superior) — most peripheral
• Right hepatic vein separates anterior from posterior sections
• Middle hepatic vein separates right from left (Cantlie's line)

---

---

• Left hepatic vein: Segments II, III (±IV)
• Middle hepatic vein: Segments IV, V, VIII (lies in Cantlie's line)
• Right hepatic vein: Segments VI, VII (±V, VIII)
• All drain into IVC at the hepatocaval junction
• Plus multiple small caudate veins (segment I) directly into IVC

---

---

---

---

• Segments II, III, IV, V, VI (anterior): Standard midline/right subcostal (Chevron) incision
• Segment I (caudate): Most difficult; accessed between IVC and portal structures; may need combined anterior + right lateral approach
• Segments VI, VII (right posterior): May require right thoracoabdominal incision or mobilization of right lobe

---

---

---

🃏 FLASHCARD SET 2: Blast Injury Classification

---

1. Blast wave (overpressure/shock wave)
2. Blast wind (high-velocity air movement)
3. Thermal energy (heat/flame)
4. Fragments/projectiles (accelerated by casing/surroundings)
5. Structural collapse (secondary to blast)

---

---

---

1. Tympanic membrane (most common; lowest pressure threshold ~35 kPa)
2. Lungs (most lethal - blast lung)
3. Bowel/intestines (gas-filled; especially right colon, terminal ileum)
4. Globe of eye (air-fluid interface in anterior chamber)
5. Sinuses

• Brain also increasingly recognized (blast TBI, even without contact injury)

---

1. Progressive hypoxia (may be DELAYED - not apparent at scene)
2. Hemoptysis
3. Dyspnea, chest pain; bradycardia/apnoea (vagal reflex) Also: pneumothorax, hemothorax, air embolism CXR: Bilateral "butterfly" perihilar infiltrates (bilateral pulmonary contusions)

---

• Barotrauma → pneumothorax
• Systemic air embolism (alveolar-venous fistulae) → stroke, MI, death Preferred approach: spontaneous ventilation or minimal pressure support; CPAP/BiPAP over intubation if possible. If intubation required: low tidal volumes (6 mL/kg), low PEEP, permissive hypercapnia.

---

• Primary blast (overpressure): Disperses by the inverse cube law (pressure ∝ 1/r³) → very rapid dissipation; only those close to blast affected
• Secondary fragments: Energy disperses by the inverse square law (energy ∝ 1/r²) → slower dissipation; fragments remain lethal at much greater distances than primary blast
• Clinical implication: casualty with no primary blast injuries can still have lethal fragment wounds from far away

---

• ATLS
• Wound debridement (treat all as contaminated/dirty wounds)
• Delayed primary closure (DPC) - never close primarily
• Serial debridement (24-48 hourly)
• Broad-spectrum antibiotics + tetanus prophylaxis
• Remove fragments only if: in joint space, near vital structures, causing ongoing infection/pain

---

---

• Depends on orientation of ear canal to shock wave and blast environment
• Is NOT ubiquitous in the presence of more severe primary blast injuries
• A patient can have blast lung without TM rupture and vice versa
• Lesson: ALL blast-exposed patients require systematic evaluation for primary blast injuries regardless of TM status - mandatory chest X-ray and abdominal assessment.

---

• Primary blast causes submucosal/subserosal hemorrhage → may not perforate immediately
• Delayed perforation at 24-72 hours as ischemic bowel necroses
• Most common: right colon and terminal ileum (most gas-filled segments) Management:
• Emergency laparotomy
• Damage control surgery: resection + temporary stoma
• Damage control resuscitation (1:1:1 ratio)
• Broad-spectrum antibiotics
• ICU postoperatively; return for reconstruction

---

1. Burns (flash burns from thermal phase; clothing ignition)
2. Inhalation injury (hot gases, CO, HCN, dust, debris)
3. Crush injuries from structural collapse
4. Exacerbation of pre-existing conditions (e.g., decompensated heart failure from physiological stress)
5. Late respiratory complications (e.g., ARDS)

---

• Radiological ("dirty bomb"): Radiation sickness + contamination of area
• Chemical agents: Nerve agents, vesicants incorporated into device
• Biological agents: Anthrax, pathogens in fragments Clinical relevance:
• Healthcare responders at risk of contamination
• Decontamination before hospital entry mandatory
• HAZMAT protocols, PPE for treating team
• Increased in suicide bombers where biological fragments (perpetrator bone/tissue) contaminate wounds of victims

---

1. Red (Immediate/T1): Life-threatening but salvageable; treat first
2. Yellow (Urgent/T2): Serious injury, stable; treat second
3. Green (Delayed/T3): Minor injuries ("walking wounded"); treat last
4. Black (Expectant/T4 + Dead): Unsurvivable injuries or dead; palliate only METHANE: declaration used for Major Incident notification (My location; Exact location; Type of incident; Hazards; Access; Number of casualties; Emergency services needed)

---

1. Scene: Tourniquet for amputation (immediate); occlusive dressing for open chest; C-spine
2. A: Airway (intubate cautiously - low pressures for blast lung); C-spine
3. B: Chest drain for pneumo/hemothorax; avoid high PEEP
4. C: IV access × 2; 1:1:1 transfusion (PRBC:FFP:platelets); permissive hypotension (SBP 80-90 mmHg unless TBI)
5. D: Neuro assessment; blast TBI common
6. E: Full exposure; identify ALL wound types (primary + secondary + tertiary)
7. DCS: Control hemorrhage; limit contamination; pack + temporary closure; ICU
8. Return: 24-48 hrs for definitive repair; DPC of fragment wounds
9. Decontamination if quinary injury suspected

---

Quick-Reference Mnemonics

• I = Caudate (independent)
• II, III = Left lateral
• IV = Quadrate / medial left
• V, VI, VII, VIII = Right lobe (V+VIII anterior; VI+VII posterior)

• Primary = Pressure/overpressure
• Secondary = Shrapnel/fragments
• Tertiary = Thrown/blunt
• Quaternary = Quirky/miscellaneous
• Quinary = Qs (chemical/radiological/biological)

---

HBC-9101 | M.S. (Branch-I) General Surgery Paper-II | June 2023

Detailed Standard Textbook Answers

---

Q.1 Aetio-Pathogenesis, Clinical Features and Management of Carcinoma Oesophagus (30 Marks)

Introduction

• Squamous Cell Carcinoma (SCC): Historically predominant; worldwide; mid/upper oesophagus
• Adenocarcinoma (AC): Rising dramatically (500% increase in Western countries over 40 years); lower oesophagus/GOJ; arising from Barrett's oesophagus

---

Aetio-Pathogenesis

Squamous Cell Carcinoma (SCC)

1. Tobacco and alcohol - most important in Western countries; synergistic effect; relative risk ×100 when combined
2. Nutritional deficiencies: Riboflavin (B2), pyridoxine (B6), vitamin C, zinc, molybdenum, selenium - common in high-risk areas
3. Nitrosamines in food (pickled vegetables, smoked/cured meats, Chinese preserved foods)
4. Achalasia - chronic stasis, nitrosamine production; 10-33x increased risk; usually mid-oesophagus SCC
5. Plummer-Vinson (Patterson-Brown-Kelly) syndrome - iron-deficiency anemia + postcricoid web; upper oesophageal SCC; middle-aged women
6. Tylosis (palmoplantar keratoderma) - autosomal dominant; near 100% risk of oesophageal SCC by age 70 (FOG2 gene mutation on chromosome 17q25)
7. Caustic stricture (lye ingestion) - SCC develops after latency of 20-40 years; 1000x increased risk
8. Celiac disease - associated with upper GI SCC
9. Radiation exposure (therapeutic irradiation to mediastinum)
10. Poor oral hygiene, HPV infection (controversial)
11. Achalasia, diverticula (stasis carcinogen contact)

Adenocarcinoma (AC)

1. Gastro-oesophageal reflux disease (GORD) - chronic acid exposure → columnar metaplasia
2. Barrett's Oesophagus (BO): Specialized intestinal metaplasia (SIM) of lower oesophagus; stepwise progression: BO → Low-grade dysplasia (LGD) → High-grade dysplasia (HGD) → Adenocarcinoma; annual cancer risk ~0.1-0.3% in BO; 0.7% in LGD; 7% in HGD
3. Obesity (BMI >30) - increases GORD; increases risk by 2-4x; central adiposity raises intraabdominal pressure
4. Male sex - M:F ratio 8:1 for AC (estrogen may be protective)
5. White race - more common than other ethnic groups
6. Smoking - risk factor for AC as well as SCC
7. Medications (nitrates, anticholinergics, calcium channel blockers) - relax LOS → GORD
8. Aspirin/NSAIDs - protective effect (reduces risk ~30%)
9. Helicobacter pylori - paradoxically protective (reduces AC risk by causing atrophic gastritis → less acid)

Molecular Pathogenesis

• Loss of TP53 (17p13) - early event
• Loss of CDKN2A (p16) - cell cycle dysregulation
• Amplification of cyclin D1 (CCND1), EGFR

• Stepwise molecular progression: CDX2 expression → MUC2, MUC5AC expression (intestinal phenotype)
• TP53 mutations in HGD/early cancer
• ERBB2 (HER2) amplification in ~15-20% of AC (targetable)
• Loss of CDKN2A, APC, SMAD4, RUNX3

---

Pathology

Macroscopic Types (WHO)

1. Fungating/polypoid - commonest; grows into lumen; well-defined margin
2. Ulcerating - necrotic center, raised indurated edges
3. Infiltrating/scirrhous - diffuse mural infiltration; fibrous response; "linitis plastica" type

Microscopic Types

• SCC: Keratin pearls, intercellular bridges; variants: basaloid, verrucous, spindle cell
• Adenocarcinoma: Glandular pattern; mucin production; arises from Barrett's (SIM); resembles gastric cancer at lower end
• Others (rare): Small cell carcinoma, adenosquamous, mucoepidermoid, sarcoma

Spread

• Submucosal lymphatic spread (longitudinal) - may be extensive (skip lesions)
• Invades: trachea (TEF), bronchi, aorta, recurrent laryngeal nerve, thoracic duct
• Circumferential involvement → dysphagia

• Rich submucosal lymphatic plexus → early nodal spread
• Upper third: Cervical, paratracheal, deep cervical nodes
• Middle third: Paratracheal, subcarinal, hilar, posterior mediastinal nodes
• Lower third: Lower mediastinal, coeliac, left gastric nodes
• "Skip metastases" - nodal spread to distant stations without local nodes

• Liver (most common), lungs, bone, brain, adrenal

---

Staging (TNM 8th Edition, AJCC/UICC)

• T1a: Mucosal layer (lamina propria/muscularis mucosae)
• T1b: Submucosa
• T2: Muscularis propria
• T3: Adventitia (no serosa in oesophagus)
• T4a: Resectable - pleura, pericardium, diaphragm
• T4b: Unresectable - aorta, vertebra, trachea

• Stage I: T1N0M0 (excellent prognosis; 5-yr survival >70%)
• Stage II: T2-3N0M0 or T1-2N1M0
• Stage III: T3N1M0 or T4aN0-1M0 or T1-4aN2M0
• Stage IVA: Any T any N M0 with T4b or N3
• Stage IVB: Any T any N M1

---

Clinical Features

Symptoms (in order of frequency)

1. Progressive dysphagia (>90%) - CARDINAL SYMPTOM; initially for solids → then liquids → complete obstruction; indicates >60% luminal narrowing; by the time dysphagia presents, cancer usually >T2
2. Weight loss (>50%) - due to dysphagia + cancer cachexia; often profound (>10% body weight)
3. Retrosternal pain/discomfort - continuous boring pain suggests mediastinal invasion
4. Odynophagia - pain on swallowing; suggests ulceration
5. Regurgitation - of undigested food
6. Cough - aspiration from dysphagia; or tracheo-oesophageal fistula (TOF)
7. Hoarseness - left recurrent laryngeal nerve involvement (left RLN more commonly affected as it loops around aortic arch)
8. Haematemesis/malaena - from tumour ulceration

Signs

• Cachexia, dehydration, malnutrition
• Cervical lymphadenopathy (Virchow's/Troisier's node - left supraclavicular)
• Hepatomegaly (liver metastases)
• Aspiration pneumonia (from TOF or stasis)
• Pleural effusion
• Bone pain from metastases

Features Indicating Irresectability ("HALT")

• Hoarseness (RLN involvement)
• Aortic invasion / fistula
• Liver/lung metastases
• Tracheal/bronchial involvement (TOF, cough with eating)
• Also: Horner's syndrome, SVC obstruction, diaphragmatic paralysis, cervical node involvement

---

Investigations

Diagnosis

1. Upper GI endoscopy (OGD) - first line:
   • Visualizes tumour; assess location, length, morphology, GOJ involvement
   • Multiple biopsies (≥6-8) for histology
   • Brush cytology if submucosal/tight stricture
   • Chromoendoscopy, NBI (narrow band imaging): detect dysplasia in Barrett's
2. Barium swallow:
   • Shows narrowing (irregular "rat-tail" or "apple core")
   • Useful if endoscopy cannot pass
   • Identifies fistula, diverticula, length of lesion

Staging

1. CT chest/abdomen/pelvis (CT-CAP) - standard:
   • Assesses T stage (invasion of mediastinal structures)
   • N and M staging (liver, lung, coeliac nodes)
   • Celiac axis, superior mesenteric nodes
   • Limitation: cannot distinguish T2 from T3; poor for early T staging
2. Endoscopic Ultrasonography (EUS) - best for T and N staging:
   • Most accurate for T staging (90%) - assesses wall layers
   • N staging 75-85%; can perform EUS-FNA of suspicious nodes
   • Cannot pass tight stricture (false-positive T staging)
3. PET-CT (FDG-PET/CT) - for M staging:
   • Detects occult distant metastases
   • Changes management in 20% of cases deemed potentially resectable on CT
   • Assesses response to neoadjuvant therapy (restaging)
   • SCC more FDG-avid than AC
4. Laparoscopy ± peritoneal lavage:
   • For lower oesophageal/GOJ tumors
   • Detects peritoneal metastases missed on CT/PET
   • Cytology of peritoneal washings
5. Bronchoscopy:
   • Mandatory for upper/mid-oesophageal SCC to exclude tracheobronchial involvement
6. MRI: Limited role; useful for assessing vertebral/aortic invasion

Nutritional Assessment

1. Nutritional assessment: BMI, albumin, pre-albumin, hand-grip strength; malnutrition universal screening tool (MUST)

---

Management

Multidisciplinary Team (MDT) Approach

---

I. Curative Intent Treatment

A. Surgery

• No distant metastases (M0)
• No unresectable local invasion (T4b excluded)
• Adequate cardiopulmonary reserve (FEV1 >1.5L for pneumonectomy equivalent)
• Performance status ECOG 0-2
• Adequate nutrition

• For mid and lower oesophageal tumours
• Abdominal phase: Upper midline laparotomy; stomach mobilized (preserving right gastroepiploic and right gastric vessels as pedicle); gastric tube fashioned along greater curvature (width 3-5 cm) using linear stapler; pyloromyotomy/pyloroplasty (speeds gastric emptying); feeding jejunostomy; 2-field lymphadenectomy (abdominal nodes)
• Thoracic phase: Right posterolateral thoracotomy (5th ICS); oesophagus mobilized; thoracic lymphadenectomy; right intrathoracic oesophago-gastric anastomosis (end-to-side circular stapler or hand-sewn); chest drains placed

• For upper/mid oesophageal tumours; high intrathoracic tumors
• Right thoracotomy (mobilize oesophagus) → laparotomy (mobilize stomach) → cervical incision (cervical anastomosis)
• Cervical anastomosis: higher leak rate but less morbid (drains to neck surface)

• No thoracotomy - blunt mediastinal dissection through hiatus (abdomen) and cervical incision
• Gastric pull-up with cervical anastomosis
• Advantages: no thoracotomy morbidity; good for high-risk patients
• Disadvantages: limited mediastinal lymphadenectomy; risk of great vessel/airway injury

• VATS + laparoscopy (totally MIO) or hybrid (VATS thoracic + open abdominal)
• TIME trial (2012): MIO equivalent oncologically to open; significantly less respiratory complications, shorter ICU stay, less blood loss
• Increasingly standard in high-volume centres

• da Vinci system; improved anastomotic technique; 3D visualization
• Growing evidence of equivalence; less anastomotic leak in some series

1. Stomach (gastric tube) - most reliable; single anastomosis
2. Colon interposition (if stomach unavailable - prior gastrectomy)
3. Jejunal free graft (microsurgical; for cervical reconstruction)

• 2-field: Mediastinal + abdominal nodes (standard Western practice)
• 3-field: Adds cervical nodes; Japanese practice; may improve survival in SCC but higher morbidity
• Minimum 15 nodes for adequate staging (UICC)

---

B. Neoadjuvant (Pre-operative) Therapy

1. Neoadjuvant Chemotherapy:
   • FLOT (5-FU + leucovorin + oxaliplatin + docetaxel): Standard for GOJ/gastric AC (FLOT4 trial, NEJM 2019); 4 cycles pre-op, 4 post-op; superior to ECF; pCR rate ~16%
   • EOF/ECF: Older regimen; less favoured now
2. Neoadjuvant Chemoradiotherapy (CRT - CROSS protocol):
   • CROSS trial (NEJM 2012): Paclitaxel + carboplatin × 5 weeks + concurrent 41.4 Gy RT → surgery vs surgery alone; R0 resection rate 92% vs 69%; pCR rate 29% (AC) and 49% (SCC); improved OS (43 vs 27 months for SCC)
   • Current standard for mid/upper oesophageal SCC and lower oesophageal/GOJ AC
   • Surgery 6-8 weeks after completion of CRT
3. Adjuvant Immunotherapy:
   • CheckMate 577 trial (NEJM 2021): Nivolumab (PD-1 inhibitor) for 1 year post-CRT+surgery in patients with residual disease (ypT1+/ypN+); significantly improved disease-free survival (22.4 vs 11 months); NOW STANDARD in eligible patients

---

C. Definitive Chemoradiotherapy (dCRT - no surgery)

• Unresectable SCC (T4b, N3)
• Cervical oesophageal SCC (surgery morbid, unproven benefit over dCRT)
• Patient unfit for surgery; refuses surgery
• SCC responds well to CRT (pCR 40-60% in some series)

---

D. Endoscopic Treatment (Early Cancer)

• Endoscopic Mucosal Resection (EMR): Suck-and-cut; for lesions <2 cm
• Endoscopic Submucosal Dissection (ESD): En-bloc resection for larger lesions; superior for R0 resection; requires expertise
• Ablation (RFA, Cryotherapy): For flat HGD/T1a in Barrett's (RFA - AIM dysplasia trial: eradication of HGD 90%)
• Criteria for endoscopic resection: T1a, well/moderate differentiation, no lymphovascular invasion, margins clear → curative

---

II. Palliative Treatment

• Most effective for rapid relief of dysphagia (within 24 hours)
• Partially or fully covered stents
• Useful for malignant TOF (covered stent seals fistula)
• Complications: stent migration, ingrowth (uncovered), food bolus obstruction

• External beam RT; EBRT 30 Gy/10 fractions
• Brachytherapy (intraluminal RT) - good local control; dysphagia-free survival
• Combined with stent: superior dysphagia control vs stent alone

• First line: Cisplatin/5-FU, Oxaliplatin/capecitabine (ESMO recommended)
• HER2-positive AC (15-20%): Add Trastuzumab (ToGA trial - improved OS 13.8 vs 11.1 months)
• Second line: Ramucirumab (anti-VEGFR2) ± paclitaxel (RAINBOW trial)
• Immunotherapy: Pembrolizumab/Nivolumab for PD-L1 positive advanced disease (KEYNOTE-590, CheckMate 648 trials)

• Nd:YAG laser - recanalization; brief symptom relief
• PDT - photosensitizer (porfimer sodium) + endoscopic light activation

• Nasojejunal/nasogastric tube
• Feeding jejunostomy (radiological or surgical)
• Parenteral nutrition if gut not accessible

• Pain control (WHO analgesic ladder)
• Anti-secretory therapy, antiemetics, steroids
• Palliative care team involvement

---

Surgical Complications of Oesophagectomy

---

Q.2 Pathophysiology, Clinical Features and Management of Acute Pancreatitis (20 Marks)

Definition

---

Aetiology (GET SMASHED mnemonic)

• G - Gallstones (most common - 40-70% in UK/India)
• E - Ethanol/alcohol (20-30%; 2nd most common)
• T - Trauma (blunt abdominal, post-ERCP - 3-5%)
• S - Steroids (corticosteroids, azathioprine)
• M - Mumps (and other viruses: Coxsackie B, CMV, HIV)
• A - Autoimmune (AIP type 1 and 2)
• S - Scorpion/snake venom; hyper-Serum triglycerides (>1000 mg/dL - Chylomicronemia)
• H - Hypercalcaemia/Hypothermia
• E - ERCP (post-procedural - 3-5%); Endoscopy-related
• D - Drugs (thiazides, furosemide, valproate, tetracyclines, azathioprine, 6-MP)
• Also: pancreatic divisum, sphincter of Oddi dysfunction, tumours, pregnancy, hereditary (PRSS1/SPINK1 mutations)

---

Pathophysiology

Trigger Mechanisms

• Small gallstones (<5 mm) or microlithiasis impacts at ampulla of Vater
• Bile reflux into pancreatic duct (common channel theory) OR
• Pancreatic duct obstruction with increased ductal pressure → rupture of acinar cells
• Common channel present in only 70%; obstruction alone sufficient

• Alcohol → acetaldehyde → direct acinar cell toxicity; alters tight junctions
• Increases pancreatic secretion (sphincter of Oddi spasm)
• Zymogen co-localization with lysosomes → intracellular activation
• Sensitizes acinar cells to cholecystokinin

Cascade of Events (Pathophysiology)

• Trypsinogen prematurely activated to trypsin within acinar cells (normally activation occurs in duodenum after enterokinase)
• Trypsin activates all other pancreatic proenzymes: chymotrypsinogen → chymotrypsin; proelastase → elastase; prophospholipase → phospholipase A2; pro-kallikrein → kallikrein

• Phospholipase A2: Destroys cell membranes → fat necrosis; generates lysolecithin (cytotoxic)
• Elastase: Digests elastic fibres of blood vessels → haemorrhage
• Lipase: Fat necrosis → saponification (calcium soaps) → hypocalcaemia
• Trypsin: Activates complement and kallikrein-kinin system → vasodilation, increased permeability
• Pancreatic oedema → local ischaemia → acinar necrosis

• Activated macrophages → TNF-α, IL-1, IL-6, IL-8 release
• Complement activation (C3a, C5a) → neutrophil chemotaxis
• Reactive oxygen species (ROS) generation → lipid peroxidation
• Pancreatic necrosis (sterile initially)
• Peripancreatic fat necrosis (saponification - white chalky deposits)
• Enzymatic digestion of surrounding tissues

• Cytokines (TNF-α, IL-1) → systemic vascular leak
• Third-space losses → hypovolaemia → renal hypoperfusion → AKI
• Activated neutrophils → pulmonary endothelial injury → ARDS (most common cause of death in severe AP)
• Myocardial depression
• Coagulopathy/DIC

• Acute Peripancreatic Fluid Collection (APFC) → Pseudocyst
• Acute Necrotic Collection (ANC) → Walled-Off Necrosis (WON)
• Infected necrosis (Gram-negative bacteria - E. coli, Klebsiella - bacterial translocation from colon)
• Pseudoaneurysm (splenic artery, GDA)
• Splenic/portal/mesenteric vein thrombosis
• Pancreatic ascites/pleural effusion (ductal disruption)

---

Severity Assessment

Revised Atlanta Classification (2012):

Scoring Systems

• Age >55 years
• WBC >16,000/mm³
• Blood glucose >200 mg/dL (non-diabetic)
• LDH >350 IU/L
• AST >250 IU/L

• Haematocrit fall >10%
• BUN rise >5 mg/dL
• Serum calcium <8 mg/dL
• PaO₂ <60 mmHg
• Base deficit >4 mEq/L
• Fluid sequestration >6 L

• 12 physiological variables + age + chronic health score
• Score ≥8 = severe AP; can be calculated at any time (advantage over Ranson's 48-hr delay)

• BUN >25 mg/dL
• Impaired mental status (GCS <15)
• SIRS present (2 or more criteria)
• Age >60 years
• Pleural effusion on imaging
• Score ≥3 = severe AP (10-fold increased mortality risk)

• CT grade (A-E: 0-4 points) + necrosis score (0-6 points)
• Total 0-10; CTSI ≥6 = severe
• CT scan only indicated if diagnosis uncertain OR no improvement after 48-72 hours (to detect necrosis); NOT routinely in first 24-48 hours (leads to underestimation of necrosis extent)

---

Clinical Features

Symptoms

1. Abdominal pain - CARDINAL; sudden onset; severe, constant; epigastric/periumbilical; radiation to the back ("boring" pain straight through to back - characteristic); relieved by leaning forward (reduces tension on mesenteric root); worsened by food
2. Nausea and vomiting - almost universal; vomiting does not relieve pain (unlike duodenal ulcer)
3. Anorexia
4. Fever - low-grade initially; high fever/rigors suggest infected necrosis

Signs

• Tachycardia, hypotension (hypovolaemia from third-space losses)
• Pyrexia (low-grade or high)
• Jaundice (gallstone aetiology; CBD compression by pancreatic head)
• Pallor, sweating

• Epigastric tenderness ± guarding (peritonism)
• Abdominal distension (ileus, ascites)
• Absent/reduced bowel sounds (ileus)
• Rebound tenderness in severe cases

• Grey-Turner's sign: Bluish-black discolouration of the flanks (retroperitoneal haemorrhage tracking to flanks) - indicates severe/haemorrhagic AP
• Cullen's sign: Periumbilical ecchymosis (haemorrhage tracking along falciform ligament) - also haemorrhagic AP
• Fox's sign: Discolouration along inguinal ligament
• Fothergill's sign: (Rare) Epigastric bruising
• Turner and Cullen signs appear 24-48 hours after onset; poor prognosis; also seen in ruptured ectopic pregnancy

---

Investigations

1. Serum amylase - rises within 2-12 hours; >3x upper limit of normal = diagnostic; returns to normal in 3-5 days (short half-life); specificity limited (raised in bowel ischaemia, perforation, parotitis, renal failure)
2. Serum lipase - more specific; remains elevated longer (7-14 days); preferred in late presentation; rises earlier in alcohol-induced AP
3. FBC: Leukocytosis; haematocrit (haemoconcentration = marker of severity); falling Hct = haemorrhagic
4. LFTs: Raised bilirubin, ALP, transaminases (gallstone aetiology); ALT >3x ULN = gallstone cause
5. Serum calcium: Hypocalcaemia (saponification; severity marker)
6. Blood glucose: Hyperglycaemia; poor prognostic indicator
7. Urea/Creatinine: Rising BUN = severity marker; AKI
8. CRP: >150 mg/L at 48h = severe AP; serial measurements monitor progress
9. ABG: Hypoxia (PaO₂ <60 = severe); metabolic acidosis
10. Coagulation: DIC in severe disease
11. Serum triglycerides: If >11 mmol/L = triglyceride-induced AP

1. Plain AXR: Not diagnostic; shows "sentinel loop" (dilated jejunum near pancreas), "colon cut-off" sign (loss of gas at splenic flexure due to transverse mesocolon inflammation), radio-opaque gallstones (20%), calcification (chronic pancreatitis)
2. CXR: Left pleural effusion; elevated left hemidiaphragm; ARDS (bilateral infiltrates)
3. USG abdomen: Gallstones (aetiology); CBD dilation; peripancreatic fluid; "snowstorm" appearance of pancreas (oedematous); limited by bowel gas in acute phase
4. CECT (Contrast-Enhanced CT) - Gold standard for severity assessment:
   • Performed at 48-72 hours (NOT immediately - necrosis demarcates over 48-72 hrs)
   • Identifies: pancreatic necrosis (non-enhancing areas), APFC, ANC, pseudocyst, WON
   • Balthazar CT Severity Index scoring
   • Indications: uncertain diagnosis; no improvement by 48-72 hours; clinical deterioration
5. MRI/MRCP: Superior to CT for ductal anatomy; detects CBD stones (>95%); avoids radiation; differentiates solid from liquid necrosis
6. EUS: CBD stones, pancreatic divisum; also therapeutic

---

Management

Initial Management (Resuscitation)

1. Aggressive IV fluid resuscitation - most important early intervention:
   • Lactated Ringer's (Hartmann's) solution preferred over normal saline (reduces SIRS, organ failure - evidence-based)
   • Rate: 250-500 mL/hour initially; target: UO >0.5 mL/kg/hr, HR <120, MAP >65 mmHg, BUN fall, haematocrit 35-44%
   • Monitor: regular reassessment; avoid over-resuscitation (abdominal compartment syndrome, ARDS)
   • WATERFALL trial (NEJM 2022): moderate-rate vs aggressive fluid resuscitation - similar outcomes; aggressive over-resuscitation harmful
2. Analgesia: IV morphine or hydromorphone (opioid-sparing with paracetamol + NSAID); epidural analgesia in severe disease; NO evidence that morphine worsens AP (Oddi spasm myth debunked)
3. Nil by mouth initially: Until pain resolves, nausea controlled, clinical improvement
4. Nasogastric tube: If vomiting or ileus; NOT routine
5. Urinary catheter + monitoring: Hourly urine output; CVP if needed
6. Oxygen supplementation: Maintain SpO₂ >95%; CPAP/mechanical ventilation if ARDS
7. Antiemetics: Metoclopramide, ondansetron
8. DVT prophylaxis: LMWH + TED stockings (when bleeding risk controlled)

---

Nutrition

• Oral feeding as soon as tolerated (mild AP: start oral feeding within 24-48 hours of admission if pain improving, no nausea)
• Severe AP: Enteral nutrition via nasojejunal (or nasogastric) tube preferred over parenteral nutrition (TPN)
• META-ANALYSIS evidence: EN reduces infection, organ failure, mortality vs TPN (Cochrane)
• Nasogastric vs Nasojejunal: PYTHON trial, CALORIES trial - NG equivalent to NJ; NG simpler
• TPN only if enteral route truly not tolerable (fistula, obstruction, severe ileus)
• Immunonutrition (glutamine, omega-3): no proven benefit in recent RCTs

---

Specific Interventions

Gallstone Pancreatitis

• Mild AP with gallstones: Cholecystectomy in SAME admission (before discharge); avoids recurrence (25-30% risk within 30 days without cholecystectomy)
• Severe AP: Delayed cholecystectomy (>4-6 weeks after clinical recovery) to avoid worsening acute phase
• CBD stones + cholangitis (Charcot's triad): Emergency ERCP within 24-72 hours
• ERCP in AP without cholangitis: NOT recommended routinely (EPAC trial) - no benefit; ERCP only if CBD obstruction persists

Alcohol-induced AP

• Abstinence counselling + alcohol liaison service referral
• Thiamine supplementation (Wernicke's prevention)
• No specific pharmacological treatment

Infected Necrosis

• Clinical deterioration after initial improvement (biphasic clinical course)
• Persistent fever/sepsis >7-10 days
• Gas in pancreatic bed on CT ("soap bubble" sign = pathognomonic of infected necrosis)

• CT-guided fine-needle aspiration (FNA) with Gram stain and culture (if clinical diagnosis uncertain)
• FNA sensitivity ~85%; increasingly not performed (clinically obvious)

1. IV antibiotics: Imipenem, meropenem, or ciprofloxacin + metronidazole (penetrate pancreatic tissue); continue 2-4 weeks
2. Percutaneous drainage (radiological): CT/US-guided catheter drainage through retroperitoneal route (left flank - avoids peritoneal contamination); 35-50% avoid surgery with drainage alone (PANTER trial)
3. Endoscopic drainage (EUS-guided): Trans-gastric access to WON with cystogastrostomy; LAMS (Lumen-Apposing Metal Stent - "Hot AXIOS"); multiple plastic stents; increasingly preferred - avoids surgery, excellent outcomes for accessible WON
4. Minimally invasive retroperitoneal pancreatectomy (MIRP/Video-Assisted Retroperitoneal Debridement - VARD): Video-assisted debridement through drainage tract; less morbid than open
5. Open surgical necrosectomy (last resort): Mortality 15-25% in infected necrosis; reserved for failure of minimally invasive approaches; technique: necrosectomy + closed continuous lavage (Beger) or open packing with planned re-laparotomy

• TENSION trial (NEJM 2021): Endoscopic step-up vs surgical step-up - endoscopic superior (less major complications, comparable outcomes); endoscopic approach now preferred when feasible

Pancreatic Pseudocyst

• Definition: Fluid collection with defined wall (>4 weeks from AP); contains amylase-rich fluid
• Asymptomatic small pseudocysts: Observe (60% resolve spontaneously)
• Symptomatic/large/infected: Drainage
  • Endoscopic (EUS-guided cystogastrostomy): First line; LAMS for <10 mm wall; excellent success rate >85%
  • Percutaneous: If endoscopic not feasible; risk of external fistula
  • Surgical (internal drainage): Cystogastrostomy/cystoduodenostomy/Roux-en-Y cystojejunostomy; for failed endoscopic/failed percutaneous

---

Complications

• Pseudocyst, WON, ANC, APFC
• Infected necrosis, pancreatic abscess
• Pseudoaneurysm (splenic artery - most common; GDA) → massive haemorrhage; treat with angioembolisation
• Fistula: pancreatico-pleural, pancreatic ascites
• Splenic/mesenteric vein thrombosis → portal hypertension, gastric varices

• ARDS (most common cause of death)
• Acute kidney injury (AKI) / ATN
• Sepsis/multi-organ failure (MOF)
• DIC
• Hypocalcaemia (tetany)
• Hyperglycaemia → new-onset diabetes mellitus
• Pleural effusion (usually left-sided; high amylase)

• Chronic pancreatitis (especially alcohol-induced)
• Exocrine insufficiency (malabsorption, steatorrhoea)
• Endocrine insufficiency (diabetes mellitus)
• Recurrence

---

Q.3 Causes of Biliary Stricture + Bile Duct Injury at Cholecystectomy and Management (20 Marks)

Part A: Causes of Biliary Stricture

Classification

I. Benign Biliary Strictures

1. Laparoscopic cholecystectomy (LC) - most common cause of bile duct injury; incidence 0.3-0.7% (higher than open 0.1-0.2%)
2. Open cholecystectomy
3. Hepatic resection (right/left hepatectomy - injury to contralateral duct)
4. Liver transplantation - anastomotic stricture (10-30%), non-anastomotic (ischaemic)
5. Hepaticojejunostomy/biliary-enteric anastomosis stenosis (recurrent)
6. Biliary drainage procedures (choledochotomy, T-tube insertion)
7. Pancreaticoduodenectomy (Whipple) - hepaticojejunostomy stricture

1. Primary Sclerosing Cholangitis (PSC) - autoimmune; multifocal intra and extrahepatic strictures; "beaded" appearance on MRCP; associated with IBD (UC in 80%); risk of cholangiocarcinoma
2. Chronic pancreatitis - fibrosis of pancreatic head → distal CBD compression; "double-duct sign" on MRCP
3. Choledocholithiasis - long-standing stones → inflammatory stricture; Mirizzi syndrome (gallstone in Hartmann's pouch compressing common hepatic duct = Type I; Type II-IV: fistula between gallbladder/duct and CHD)
4. IgG4-related sclerosing cholangitis (Type 1 AIP) - mimics PSC/cholangiocarcinoma; responds to steroids
5. Recurrent pyogenic cholangitis (Oriental cholangiohepatitis) - intrahepatic stones + strictures; Southeast Asia; Clonorchis sinensis
6. Parasitic infections: Clonorchis sinensis, Opisthorchis, Ascaris lumbricoides
7. HIV cholangiopathy (Cryptosporidium, CMV) - papillary stenosis + sclerosing cholangitis
8. Tuberculosis of lymph nodes (porta hepatis)

1. Blunt/penetrating abdominal trauma
2. Radiation stricture (post-radiation therapy for abdominal malignancy)

1. Choledochal cyst (type IV = intrahepatic + extrahepatic; post-excision stricture)
2. Biliary atresia (neonatal; Kasai portoenterostomy ± liver transplant)
3. Caroli disease (congenital intrahepatic biliary ectasia)

II. Malignant Biliary Strictures

1. Cholangiocarcinoma - most common malignant stricture
   • Klatskin tumour (hilar cholangiocarcinoma) - at confluence of right and left hepatic ducts; Bismuth-Corlette classification
   • Distal CBD cholangiocarcinoma
   • Intrahepatic cholangiocarcinoma
2. Pancreatic head carcinoma - distal CBD stricture; "double duct sign"
3. Ampullary carcinoma - periampullary
4. Gallbladder carcinoma - direct invasion of CHD
5. Metastatic lymphadenopathy at porta hepatis (stomach, colon, lymphoma)
6. Hepatocellular carcinoma - bile duct invasion (rare)

---

Part B: Bile Duct Injury at Cholecystectomy and Management

Incidence and Significance

• Laparoscopic cholecystectomy (LC): BDI 0.3-0.7% (3-7 per 1000 operations)
• Open cholecystectomy: 0.1-0.2%
• Higher rates with LC, especially in early learning curve; now stabilized
• Most devastating complication of LC; carries significant morbidity, mortality and medicolegal consequences
• 85% of bile duct injuries occur during cholecystectomy (Sabiston 21e)
• Only 15% recognized intraoperatively; 85% present post-operatively

Causes/Risk Factors

• Failure to achieve Critical View of Safety (CVS) before clipping/cutting
• Colinearity of cystic duct and common hepatic duct (when gallbladder retracted cephalad without lateral tension on Hartmann's pouch)
• "Classic injury pattern": CBD mistaken for cystic duct → excised; right hepatic artery mistaken for cystic artery → divided
• Anatomical variations: low insertion of cystic duct; accessory hepatic ducts; right hepatic artery tortuous

• Excessive cephalad retraction without counteraction inferolaterally
• Aggressive haemostasis near Calot's triangle (clips/diathermy)
• Inadequate exposure; poor visualization
• Excessive bleeding obscuring anatomy (should STOP and convert to open)
• Failure to use cholangiography

• Laparoscopic bias / confirmation bias (most injuries not recognized intraoperatively)
• Surgeon fatigue, time pressure
• Inexperience (more common in low-volume centres)
• Difficult cases: acute cholecystitis, obesity, contracted gallbladder, cirrhosis, previous surgery

---

Strasberg Classification of Bile Duct Injuries

• Right hepatic artery injured in 12-47% of E-type injuries
• Dramatically worsens prognosis and reconstruction options
• MUST be assessed pre-reconstruction (CT angiography, MRA)

---

Clinical Presentation

• Bile appearing in operative field
• Inability to define anatomy on cholangiogram
• Anatomical discrepancy (clip placed, duct still visible)

• Bile leak: Bile from drain; bile peritonitis (no drain placed); RUQ pain; fever; rising bilirubin
• Obstructive jaundice: Increasing bilirubin + ALP; if complete transaction/clip on duct

• Biliary stricture: Deepening jaundice; pruritus; cholangitis (Charcot's triad: fever + jaundice + RUQ pain; Reynolds' pentad + septic shock + confusion)
• Secondary biliary cirrhosis: From prolonged obstruction (rare with modern management)

---

Investigations

1. LFTs: Rising bilirubin, ALP; raised transaminases (suggest hepatic ischaemia from vascular injury)
2. USG abdomen: Biloma; intrahepatic ductal dilatation; free fluid
3. CT abdomen: Biloma; extent of injury; associated vascular injury
4. MRCP (first line for anatomy): Non-invasive; defines biliary anatomy above and below injury; ductal dilatation; communication with main duct
5. ERCP: Diagnostic + therapeutic; identifies leak site; allows stent placement; cannot image above tight stricture
6. Hepatobiliary scintigraphy (HIDA scan): Shows bile leak; useful when ERCP/MRCP inconclusive
7. Percutaneous Transhepatic Cholangiography (PTC): When ERCP fails; also therapeutic (PBD - external drainage)
8. CT/MR angiography: Essential before any surgical reconstruction to identify associated right hepatic artery injury

---

Management

Principle: "Recognition, Control, Referral to Expert Centre, Reconstruction"

• Correct sepsis (IV antibiotics: piperacillin-tazobactam/cephalosporin + metronidazole)
• Drain biloma/collections (percutaneous CT-guided)
• Correct coagulopathy (Vitamin K, FFP if jaundiced)
• Nutritional optimization

---

A. INTRAOPERATIVE Recognition

1. Stop; convert to open if any suspicion of BDI during LC
2. On-table cholangiography: Inject contrast via catheter in suspected cut duct end; delineate anatomy
3. If injury confirmed: DO NOT attempt laparoscopic repair (unless highly experienced biliary surgeon)
4. Call for senior help immediately; do not proceed without expertise

• Type A (cystic duct/Luschka leak): Clip cystic duct stump; fulguration of Luschka duct; place drain
• Type D (small lateral injury): Primary repair over T-tube; drain placed
• Type E (major transaction): DO NOT attempt primary repair in a contaminated field during acute cholecystitis by a non-biliary specialist; place drain; refer to specialist centre

• Immediate reconstruction (same operation): ONLY if biliary surgeon immediately available + no sepsis + no bile duct tissue loss + clean field
• Staged approach (preferred if any doubt): drain + refer; reconstruction after 6-8 weeks (reduces inflammatory response, fibrosis)

---

B. ENDOSCOPIC Management (ERCP)

• Type A injury (bile leak from cystic duct / Luschka duct)
• Type D (partial lateral injury)
• Low E-type strictures accessible to ERCP

1. ERCP; cannulation of CBD; cholangiogram to identify leak/stricture
2. Biliary stenting: Plastic stents (10 Fr, 7-10 cm); bridges the leak/stricture; stent placed across defect
3. Sphincterotomy: Reduces transsphincteric pressure gradient; promotes drainage
4. Serial stent exchanges every 3 months; progressively larger/more stents
5. Duration: 12-18 months for benign strictures; 90% success rate for low strictures
6. Self-expanding metal stents (SEMS): Fully covered for refractory strictures; higher radial force

---

C. PERCUTANEOUS Transhepatic Management (PTC/PTBD)

• Failed ERCP (complete occlusion; cannot pass stricture from below)
• Roux-en-Y anatomy (post-bypass - no access to papilla)
• High hilar strictures (E3/E4)
• Rendezvous procedure (combined ERCP + PTC)

1. Ultrasound/fluoroscopy-guided puncture of dilated intrahepatic duct
2. Wire passage through stricture into duodenum
3. External drainage initially → internal-external drainage → internalized stent
4. Pre-operative biliary decompression for 4-6 weeks before surgical reconstruction (reduces jaundice, cholangitis, improves liver function, facilitates dissection)

---

D. SURGICAL Reconstruction

• Immediate (intraoperative recognition): Only by experienced biliary surgeon; no inflammation; clean field
• Early (<72 hours): If injury recognized early post-op; minimal inflammation
• Delayed (6-8 weeks): After biliary drainage, resolution of bile peritonitis/inflammation, nutritional optimization; preferred in most cases

1. Complete excision of all damaged/ischaemic duct
2. Adequate proximal ductal length for tension-free anastomosis
3. Mucosa-to-mucosa anastomosis
4. Healthy, well-vascularized tissue
5. Roux-en-Y limb of sufficient length (40-60 cm) to prevent reflux
6. Transanastomotic stents (optional; some series show benefit in difficult cases)

• Gold standard for E-type injuries (E1-E4)
• 60-cm defunctionalized Roux limb; end-to-side hepaticojejunostomy
• For E4 (separated right and left): bilateral hepaticojejunostomies (one Roux loop with separate anastomoses, or two separate loops)
• Mucosa-to-mucosa with absorbable sutures (PDS 4/0 or 5/0); single layer

• Only for acute intraoperative recognition with minimal tissue loss; NO tension; excellent blood supply
• Generally avoided (poor results; stricture rate >50% at 5 years)
• T-tube stenting used to reduce stricture rate

• For high hilar injuries where conventional dissection at porta hepatis not feasible
• Segment III duct in the umbilical fissure accessed

• Success rate: 80-90% at 5-10 years (good-excellent biliary drainage)
• Complications: recurrent stricture (10-20%), cholangitis, hepatic fibrosis, portal hypertension
• Long-term follow-up essential (annual LFTs for life; MRCP if deterioration)

---

Prevention of BDI

1. Critical View of Safety (CVS - Strasberg, 1995): MANDATORY before any clip application
   • Lower 1/3 of gallbladder dissected free from liver
   • Only 2 structures seen entering gallbladder (cystic duct + cystic artery)
   • Hepatocystic triangle cleared of fat and fibrous tissue
   • CVS significantly reduces BDI risk
2. Intraoperative cholangiography: Identifies BDI immediately in 60% of cases when performed; reduces injury extent
3. BAIL-OUT procedures if CVS cannot be achieved:
   • Fundus-first (top-down) approach
   • Subtotal cholecystectomy (leave Hartmann's pouch if anatomy unsafe)
   • Convert to open (no shame; reduces major BDI)
4. Laparoscopic ultrasound: Identifies CBD in difficult cases
5. Low threshold for conversion: Acute/gangrenous cholecystitis; Mirizzi syndrome; unclear anatomy

---

Q.4 Write in Brief (30 Marks - 10 marks each)

Q.4(a) Gastrointestinal Stromal Tumours (GIST) (10 Marks)

Definition and Incidence

---

Pathogenesis and Molecular Biology

• KIT = type III receptor tyrosine kinase; encoded by c-KIT proto-oncogene (chromosome 4q12)
• Mutations in exon 11 (juxtamembrane domain, most common - 60-70%; best prognosis with imatinib), exon 9 (extracellular domain, ~10%; poorer response), exon 13, exon 17
• Activating mutations → constitutive KIT signalling → uncontrolled proliferation, inhibition of apoptosis

• Platelet-derived growth factor receptor alpha; common in gastric GISTs; often exon 18 D842V mutation (imatinib-resistant)

• SDH-deficient GISTs (succinate dehydrogenase mutations; SDHA, SDHB, SDHC, SDHD) - Carney triad, Carney-Stratakis syndrome; mostly gastric; young patients; lymph node metastases unusual
• NF1 (neurofibromatosis type 1) associated
• BRAF mutation (rare)
• KRAS mutation (extremely rare)

• CD117 (c-KIT): positive in 95% of GISTs - key diagnostic marker
• DOG1 (ANO1): 97% sensitive; positive even in KIT-negative GISTs; highly specific
• CD34: positive in 70-80%
• SMA: 30-40%; desmin, S-100 usually negative

---

Sites of Origin

• Stomach: 60-70% (most common; best prognosis)
• Small intestine: 20-30% (2nd most common; small bowel GISTs more aggressive)
• Colorectum: 5% (rectal GISTs often aggressive)
• Oesophagus: 5%
• Extra-GI (mesentery, omentum, retroperitoneum): 5%

---

Risk Stratification (Modified Fletcher/Armed Forces Institute of Pathology)

1. Tumour size (cm)
2. Mitotic rate (per 50 HPF or per 5 mm²)
3. Site (gastric GISTs have better prognosis for same size/mitotic rate vs intestinal)

---

Clinical Features

• Asymptomatic (incidental finding on imaging/endoscopy - ~20%)
• GI bleeding - most common presenting feature; haematemesis/malaena (from mucosal ulceration); iron-deficiency anaemia
• Abdominal mass - palpable in large tumours
• Abdominal pain/discomfort - from mass effect
• Dysphagia (oesophageal)
• Obstruction (small/large bowel)
• Perforation (rare; aggressive tumours)

---

Investigations

1. Endoscopy (OGD/colonoscopy): Submucosal bulge with intact overlying mucosa; smooth, mobile mass; central umbilication/ulceration if large; appearance does NOT distinguish GIST from other submucosal lesions
2. EUS (Endoscopic Ultrasonography) - most useful for characterization:
   • Arises from 4th layer (muscularis propria) on EUS
   • Hypoechoic mass; EUS-FNA for tissue diagnosis (cytology + immunochemistry: CD117/DOG1)
3. CT chest/abdomen/pelvis: Define size, extent, vascularity (GISTs are hypervascular), liver metastases, peritoneal deposits; essential for staging
4. MRI: Superior for rectal GISTs and hepatic metastases
5. PET-CT: Highly sensitive for GIST (highly FDG-avid); used for response assessment after imatinib (earlier than CT - "metabolic response" precedes morphological response)
6. Histology + IHC: Definitive diagnosis; CD117, DOG1, CD34; mutation analysis (exon 11 vs 9 vs PDGFRA) guides imatinib dosing

---

Management

Surgical Treatment

• Surgery = ONLY curative treatment
• R0 resection (microscopically clear margins) - primary goal
• Tumour >2 cm: resection (risk of progression and bleeding)
• Tumour <2 cm (incidental, asymptomatic): surveillance vs resection (decision based on EUS features - irregular border, cystic spaces, echogenic foci, lymphadenopathy = high risk → resect)

• Wide local excision with 1-2 cm margins (segmental resection); NOT wide anatomical resection as in carcinoma
• No routine lymphadenectomy (lymph node spread rare)
• Avoid tumour rupture (converts to R2; significantly worsens prognosis - intraabdominal seeding)
• Laparoscopic approach safe for gastric GISTs <5 cm (NCCN guideline)
• Gastric GISTs: wedge resection, partial/distal gastrectomy based on location
• Small bowel GISTs: segmental resection + end-to-end anastomosis
• Rectal GISTs: neoadjuvant imatinib for 6-12 months first to downsize (avoid APR); then low anterior resection

Imatinib (Gleevec/Glivec) - Tyrosine Kinase Inhibitor (TKI)

• KIT/PDGFRA inhibitor - first targeted therapy in solid tumours (paradigm for precision oncology)

• High-risk GISTs (Joensuu criteria): 3 years of imatinib (400 mg/day)
• SSGXVIII/AIO trial: 3 years vs 1 year adjuvant imatinib → significantly improved recurrence-free survival AND overall survival; 5-yr RFS 65.6% vs 47.9%
• Intermediate-risk: 1 year adjuvant imatinib (debated)
• Dose: 400 mg/day (standard); 800 mg/day for exon 9 mutations

• For large/unresectable/locally advanced GISTs
• Convert unresectable to resectable; reduce surgical morbidity
• Maximum response by 3-6 months; then surgery
• Rectal GISTs: avoid APR → sphincter-sparing

• First line: Imatinib 400 mg/day (exon 11); 800 mg/day (exon 9 or progression on 400 mg)
• PFS ~24 months; median OS >5 years (revolution from <20 months pre-imatinib)
• Second line (imatinib failure): Sunitinib (multi-targeted TKI; VEGFR, KIT, PDGFR)
• Third line: Regorafenib (sorafenib analog)
• Fourth line: Ripretinib (switch-control KIT/PDGFRA inhibitor)
• PDGFRA D842V mutation (imatinib-resistant): Avapritinib (BLU-285) - highly effective

• CT or MRI every 3-6 months
• PET-CT for early response (2-4 weeks: "PET flare" → "PET response")
• Criteria: mRECIST or Choi criteria (CT density reduction + size change)

---

Prognosis

• Complete resection (R0): 5-yr survival ~50-65% (without adjuvant); >85% with 3yr adjuvant imatinib
• Liver/peritoneal metastases with imatinib: 5-yr survival ~50%
• Better prognosis: gastric site, low mitotic rate, small size, exon 11 mutation
• Tumour rupture: Worse prognosis equivalent to peritoneal metastases

---

Q.4(b) Crohn's Disease (10 Marks)

Definition

---

Epidemiology and Aetiology

• Incidence: 5-10/100,000/year (Western countries); rising in developing world
• Bimodal age distribution: peak 15-30 years; second peak 60-80 years
• Equal sex distribution (slightly more females)
• More common in White and Jewish populations

1. Genetic: NOD2/CARD15 mutations (chromosome 16q12) - most important; found in 15-20% of CD; NOD2 = intracellular pattern recognition receptor for bacterial muramyl dipeptide; homozygous mutation = 40x increased risk; ATG16L1, IRGM (autophagy genes); IL-23R variants; >200 susceptibility loci identified
2. Dysbiosis: Altered gut microbiome (decreased Firmicutes, increased Proteobacteria); loss of commensal bacteria diversity; role of Mycobacterium avium paratuberculosis (MAP) controversial
3. Immune dysregulation: Defective mucosal barrier function → abnormal innate immune activation; Th1 and Th17 skewed response; TNF-α, IL-12, IL-23 central mediators; Th2 (UC) vs Th1 (CD) oversimplification
4. Environmental: Smoking (increases CD risk and severity; opposite of UC where smoking protective); NSAIDs, oral contraceptives (possible); appendicectomy (protective in UC, not CD); hygiene hypothesis; vitamin D deficiency
5. Epigenetics: DNA methylation changes in inflamed mucosa

---

Pathology

• Terminal ileum only (30%)
• Ileocolon (40-50%) - most common
• Colon only (20%)
• Upper GI/jejunum (5%)

• Skip lesions - areas of normal mucosa between diseased segments (pathognomonic)
• Cobblestone mucosa - linear ulcers + transverse fissuring + mucosal islands
• Creeping fat - mesenteric fat wraps around bowel ("fat wrapping")
• "Rubber hose" thickening - transmural fibrosis
• Serosal inflammation; fistulae to adjacent structures; strictures
• Rectal sparing (unlike UC); anal disease common (fissures, fistulae, skin tags)

• Transmural inflammation - all layers (mucosa, submucosa, muscularis, serosa)
• Non-caseating granulomas (Langhans-type giant cells) - PATHOGNOMONIC; present in 50-60% of specimens
• Fissuring ulcers (knife-like deep ulcers)
• Lymphoid aggregates (Peyer's patches)
• Neuronal hyperplasia, submucosal fibrosis

• B1: Non-structuring, non-penetrating (inflammatory)
• B2: Stricturing (fibrosis)
• B3: Penetrating (fistulising/abscess)
• P: Perianal modifier

---

Clinical Features

1. Diarrhoea - most common; semi-formed; NOT always bloody (unlike UC)
2. Abdominal pain/cramping - especially RIF (terminal ileal disease); colicky or constant; worse post-meals (stimulates peristalsis)
3. Weight loss and malnutrition - from malabsorption (ileal disease), reduced intake, increased catabolism
4. Mass in RIF - palpable inflammatory mass (ileocolic CD); may represent phlegmon/abscess
5. Fever - from systemic inflammation or abscess
6. Rectal bleeding - less prominent than UC; present in colonic CD

• Perianal fistulae, fissures, skin tags, abscesses
• May PRECEDE intestinal symptoms by years
• Complex fistulae (rectovaginal, rectourethral)
• Hallmark of CD (not UC)

1. Obstruction - from stricture (fibrotic B2); most common indication for surgery
2. Fistulae - enterocutaneous, enteroenteric, enterovesical, enterovaginal, perianal
3. Abscess - mesenteric, pelvic, perianal (from fistula-in-ano); B3 behaviour
4. Perforation - free perforation (rare in CD; more common in UC); contained perforation (abscess) common
5. Haemorrhage - massive (rare in CD)
6. Cancer risk - increased risk of small bowel and colonic adenocarcinoma (but less than UC); surveillance needed in long-standing colonic CD
7. Growth retardation - in paediatric CD (inflammatory cytokines impair GH axis)

---

Extraintestinal Manifestations (EIM)

• Peripheral arthropathy (Type I: pauciarticular, large joints; Type II: polyarticular, small joints)
• Erythema nodosum (tender red nodules; anterior shin)
• Oral aphthous ulcers
• Episcleritis

• Ankylosing spondylitis (HLA-B27; axial; requires separate treatment)
• Pyoderma gangrenosum (rare; deep ulcers; treat with systemic steroids/infliximab)
• Primary Sclerosing Cholangitis (PSC) (rare in CD; more common in UC)
• Uveitis (can be blinding if untreated)

• Oxalate kidney stones (ileal disease → fat malabsorption → oxalate hyperabsorption)
• Gallstones (ileal disease → bile salt malabsorption → lithogenic bile)
• B12 deficiency (terminal ileum disease/resection)
• Folate deficiency (small bowel disease/sulfasalazine)
• Fat-soluble vitamin deficiency (A, D, E, K)
• Osteoporosis (steroids + malabsorption)
• Anaemia (iron deficiency + B12 deficiency + anaemia of chronic disease)

---

Investigations

• FBC: anaemia; leukocytosis
• CRP, ESR, albumin: disease activity, nutritional status
• LFTs: hepatic EIM (PSC, fatty liver, drug hepatotoxicity)
• B12, folate, iron stores, vitamin D

• Faecal calprotectin (FC): Excellent marker of intestinal inflammation; correlates with mucosal healing; >250 μg/g = active disease; used to differentiate IBD from IBS; monitor response; lower with mucosal healing
• Faecal lactoferrin: Alternative marker
• Culture/sensitivity: exclude infection (Clostridium difficile, Campylobacter, Salmonella)

• Ileocolonoscopy with biopsies - gold standard for diagnosis and assessment
• Features: aphthous ulcers, cobblestone mucosa, skip lesions, strictures, rectal sparing
• Biopsies from 5 sites including terminal ileum
• Capsule endoscopy: For small bowel CD (jejunal/proximal ileal) where conventional endoscopy cannot reach; higher yield than MRI for mucosal disease; contraindicated in suspected strictures
• Double-balloon enteroscopy: Diagnostic + therapeutic (dilation) for small bowel CD

• MR Enterography (MRE) - gold standard for small bowel CD:
  • No radiation; excellent for transmural disease, mesenteric changes, fistulae, abscesses
  • Active inflammation: mucosal enhancement, wall thickening, restricted diffusion, "comb sign" (hyperemic mesenteric vessels)
  • Fibrotic stricture: wall thickening without hyperenhancement
• CT Enterography: Alternative to MRE if MRI unavailable; radiation concern (young patients)
• Small bowel follow-through (SBFT): Older modality; "string sign of Kantor" (tight stricture in terminal ileum)
• Ultrasound: Bowel wall thickening; free fluid; mesenteric fat; fistulae; operator-dependent

---

Medical Management

1. Inducing Remission

• Budesonide MMX: For ileal/right colonic CD; first-pass hepatic metabolism minimises systemic effects; 9 mg/day for 8-16 weeks
• Prednisolone: 40-60 mg/day oral; taper over 8-12 weeks; NOT for maintenance (steroid dependence)
• 5-ASA (mesalazine): Limited evidence in CD (unlike UC); may have role in mild colonic CD

• Systemic corticosteroids (prednisolone/IV hydrocortisone): Effective for induction; 70-80% response
• IV hydrocortisone or methylprednisolone: For hospitalized severe disease

• Exclusive enteral nutrition (EEN): Equally effective as steroids for induction in PAEDIATRIC CD (avoids growth retardation); formula/elemental feeds for 6-8 weeks; also promotes mucosal healing; used pre-operatively for bowel rest

2. Maintaining Remission (Steroid-sparing)

• Azathioprine (AZA) / 6-Mercaptopurine (6-MP): Purine antimetabolites; reduce steroid dependence; maintain remission (50-70% at 2 years); onset 3-6 months (slow); dose: AZA 2-2.5 mg/kg/day; check TPMT before (high TPMT → poor response; low TPMT → toxicity); SE: myelosuppression, hepatotoxicity, pancreatitis, lymphoma risk (EBV-associated)
• Methotrexate (MTX): 25 mg/week IM/SC (induction), 15 mg/week (maintenance); SE: hepatotoxicity, teratogenicity, pneumonitis; used in AZA-intolerant patients

• Anti-TNF agents:
  • Infliximab (Remicade): Chimeric IgG1 antibody; IV infusion (5 mg/kg at 0,2,6 weeks, then every 8 weeks); highly effective for moderate-severe CD and fistulising disease; mucosal healing; "top-down" strategy evidence (SONIC trial: infliximab + AZA > monotherapy)
  • Adalimumab (Humira): Fully human IgG1; SC injection (160/80/40 mg); equivalent efficacy to infliximab; useful if infliximab antibodies/intolerance
  • Certolizumab pegol (Cimzia): PEGylated Fab fragment; SC; no placental transfer (safe in pregnancy)
  • SE: infusion reactions; TB reactivation (screen BEFORE starting); opportunistic infections; de-novo demyelination; lupus-like syndrome; worsening heart failure; lymphoma
• Anti-integrin:
  • Vedolizumab (Entyvio): Humanised anti-α4β7 integrin antibody; selectively inhibits gut lymphocyte trafficking; IV; gut-selective (no systemic immunosuppression); 2nd line or for patients where anti-TNF failed or contraindicated; effective for maintenance; safer profile
• Anti-IL-12/23:
  • Ustekinumab (Stelara): Monoclonal antibody against p40 subunit of IL-12 and IL-23; SC injection after IV loading; effective in CD (UNIFI extension); particularly good for perianal disease
• Anti-IL-23 (newer):
  • Risankizumab (Skyrizi): p19 subunit of IL-23; SC; highly effective for moderate-severe CD (ADVANCE, MOTIVATE trials); approved 2022

• Metronidazole + ciprofloxacin: For perianal disease, septic complications, post-operative prophylaxis (reduces recurrence)

---

Surgical Management

Indications for Surgery

1. Intestinal obstruction (most common; from fibrotic stricture unresponsive to medical therapy)
2. Failure of medical therapy (inadequate control of symptoms on maximal therapy)
3. Fistulae (internal: enteroenteric, enterovesical, enterovaginal; external: enterocutaneous)
4. Abscess (mesenteric/pelvic)
5. Free perforation (rare emergency)
6. Haemorrhage (massive, uncontrolled)
7. Dysplasia/carcinoma
8. Growth failure in children (surgery allows period of growth)
9. Perianal disease (abscesses - incision and drainage; complex fistulae - seton placement, fistulotomy)

Surgical Principles (CRUCIAL: BOWEL CONSERVATION)

1. Minimal resection - resect only grossly diseased bowel; macroscopic margins; microscopic involvement of margins does NOT increase recurrence (conservative resection equivalent)
2. Avoid short bowel syndrome (cumulative resections lead to SBS)
3. Stricturoplasty (instead of resection for short fibrous strictures):
   • Heineke-Mikulicz (H-M): For strictures <10 cm; longitudinal incision closed transversely
   • Finney: For 10-25 cm strictures; side-to-side anastomosis
   • Michelassi (isoperistaltic side-to-side stricturoplasty): For long strictures >25 cm; bowel folded on itself
   • Stricturoplasty does NOT increase cancer risk; tissue left for biopsy
4. Laparoscopic approach (preferred for primary ileocolic resection):
   • LASAN trial: Laparoscopic ileocolic resection; equivalent recurrence; better short-term recovery
   • Conversion rate ~10-15%
5. Proximal diversion (defunctioning ileostomy/colostomy) for complex perianal disease, allowing healing before restoration
6. Post-operative recurrence prevention: Metronidazole; azathioprine; anti-TNF (infliximab) after resection (PREVENT trial: reduced endoscopic but not clinical recurrence)

• Ileocaecal resection: For terminal ileal/ileocolic CD (most common surgical procedure); 5-10 cm margins; ileocolic anastomosis (stapled or hand-sewn; side-to-side preferred)
• Colectomy + IRA (ileorectal anastomosis): For colonic CD with rectal sparing
• Proctocolectomy + end ileostomy: For pancolonic CD with severe rectal disease; restorative proctocolectomy (pouch) contraindicated in CD (high pouch failure rate)
• Perianal disease management: Examination under anaesthesia (EUA) + MRI fistulagram + seton placement; LIFT procedure; fistula plug; infliximab + seton; closure only after disease control

---

Q.4(c) Anorectal Malformations (ARM) (10 Marks)

Definition

---

Embryology

• Cloaca (common chamber for GI and urogenital tracts) is divided by the urorectal septum (Tourneux-Rathke fold) descending from above
• Completed by 7th week → anterior urogenital sinus (bladder + urethra) and posterior anorectal canal
• Perineal body formed at junction
• Cloacal membrane ruptures → anal opening at 8th week
• Failure of urorectal septum descent → ARM; failure of cloacal membrane rupture → imperforate anus without fistula

---

Krickenbeck Classification (2005 - International Consensus)

1. Perineal (cutaneous) fistula - most common ARM in males; ectopic anus with perineal fistula opening; well developed sphincter mechanism
2. Rectourethral fistula (RUF):
   • Bulbar (low) - fistula to bulbar urethra; more common; better continence
   • Prostatic (high) - fistula to prostatic urethra; more complex
3. Rectovesical fistula - fistula to bladder neck; rarest; very high; poor prognosis for continence
4. Imperforate anus without fistula (common in Down syndrome)
5. Rectal atresia/stenosis (rare)

1. Perineal (cutaneous) fistula - ectopic anus opening on perineum
2. Vestibular fistula - most common in females; opens in posterior fourchette/vestibule; good prognosis for continence after repair
3. Cloaca - single perineal opening for rectum, vagina, and urethra; most complex female ARM; common channel length determines management
4. Imperforate anus without fistula
5. Rectal atresia/stenosis

• Low (infralevator) ARM: Bowel passes through levator ani muscle; fistula to perineum/vestibule; good prognosis
• Intermediate ARM: Bowel ends at level of levators
• High (supralevator) ARM: Bowel ends above levator ani; fistula to urethra/bladder/vagina; complex; poorer continence

---

Associated Anomalies (VACTERL)

• V - Vertebral anomalies (sacral agenesis; hemivertebrae) - 30-50%; sacral ratio < 0.4 = poor prognosis
• A - Anal atresia (the ARM itself)
• C - Cardiac defects (30-40%): ASD, VSD, ToF; echocardiography mandatory
• TE - Tracheo-Esophageal fistula/Esophageal atresia (10%)
• R - Renal/urological anomalies (50%): horseshoe kidney, renal agenesis, VUR, hydronephrosis; MCUG, renal USS mandatory
• L - Limb defects (15%)
• Also: Down syndrome (trisomy 21) association with ARM
• Currarino triad: Sacral agenesis + presacral mass (anterior meningocele/teratoma) + ARM
• Genitourinary anomalies in females especially with cloaca (vaginal anomalies, bicornuate uterus, hydrocolpos)

---

Clinical Assessment

• Absent anal opening (imperforate anus) - usually diagnosed on routine newborn examination
• Meconium passage via abnormal route: urethra (fistula to urinary tract), perineum, vaginal/vestibular opening
• "Bucket-handle" deformity (perineal pit without fistula opening)
• Anal stenosis: tight anal canal

1. Perineal inspection:
   • "Good bottom" (perineal body, midline groove, anal dimple, good buttocks) → low ARM; good prognosis
   • "Flat bottom" (absent midline groove, flat perineum, absent dimple) → high ARM; complex; poor prognosis
2. External fistula identification (perineum, vestibule)
3. Sacrum examination/palpation (sacral agenesis)
4. Spine inspection (myelomeningocele)
5. Limbs, cardiac, renal assessment

• Lateral X-ray in inverted position (or prone) with metallic marker at anal dimple
• Gas shadow in rectum; distance of rectal gas from skin marker
• Largely replaced by cross-table lateral prone X-ray and MRI
• Unreliable before 24 hours (gas hasn't reached rectal pouch)

• Perineal ultrasound: Distance of rectum to skin (>15 mm = high; <15 mm = low/perineal)
• Cross-table lateral prone X-ray at 24 hours
• MRI: Best for defining pelvic muscle anatomy, sacrum, spinal cord; identifies tethered cord
• Cystoscopy/vaginoscopy (PSARP planning): Defines fistula anatomy in complex cases
• Distal colostogram (loopogram): Defines rectal anatomy and fistula when colostomy performed; most accurate

• CXR, echocardiography (cardiac)
• Renal USS, MCUG (renal/urological)
• Spinal MRI (sacral defects, tethered cord)
• Chromosomal karyotype (Down syndrome)

---

Management

Principles

1. Ensure bowel decompression (immediate: initial management)
2. Identify and repair fistula
3. Achieve continence (long-term goal; depends on ARM type and sacral/sphincter anatomy)
4. Multidisciplinary team: Paediatric surgeon, urologist, orthopaedic surgeon, cardiologist, social worker

---

LOW ARMs (Perineal fistula, Vestibular fistula)

• Minimal PSARP or perineal anoplasty within first 48-72 hours of life
• Dilate perineal fistula → perform anoplasty (move anal opening to correct anatomical position within external sphincter) without colostomy
• Excellent prognosis (>90% continence)

• Definitive PSARP repair either:
  • Early (neonatal, within first 3 days): Without colostomy if experienced surgeon
  • OR with protective diverting colostomy → elective PSARP at 1-3 months
• Excellent prognosis (~90% continence)

---

HIGH/COMPLEX ARMs (Rectourethral, Rectovesical, Cloaca)

• Divided sigmoid colostomy (left iliac fossa): Creates complete diversion; prevents urinary contamination in rectourethral fistula; decompresses bowel
• Left colon (descending sigmoid) used; not transverse (insufficient length for later PSARP)
• Divided (not loop) colostomy preferred: prevents feces from contaminating distal limb; allows distal colostogram

1. Patient prone in jackknife position (lithotomy for cloaca)
2. Electrical muscle stimulator identifies sphincter complex
3. Midline sagittal posterior incision from coccyx to perineum; splits all structures in midline including external sphincter, levator ani, muscle complex, puborectalis (under electrical stimulation guidance)
4. All structures divided and tagged with silk sutures (for precise reconstruction)
5. Rectum identified and mobilized from fistula (ligation and division of urethral/bladder fistula)
6. Tapering of dilated rectum if needed (to fit within sphincter mechanism)
7. Reconstruction: muscle complex, levator ani, external sphincter reconstructed around pulled-through rectum
8. New anus created at precise centre of sphincter mechanism
9. Protection sutures through skin to prevent stenosis

• For high ARMs (rectovesical fistula);
• Laparoscopic mobilization of rectum from above + perineal component; avoids full PSARP incision
• Less disruption of posterior muscle complex; equivalent continence results in selected cases

• Total Urogenital Mobilization (TUM) - complex; common channel length determines approach (<3 cm: TUM; >3 cm: separate urethral and vaginal reconstruction)
• Vaginal reconstruction (vaginal switch, vaginal replacement); urological expertise required

• 4-8 weeks after PSARP
• After confirming anal healing; calibration of neoanal canal
• Anal dilations started 2 weeks post-PSARP; progressive dilators (Hegar) to achieve adequate calibre before closure

---

Long-term Management

• Even after technically perfect repair, many patients require bowel management
• Voluntary bowel movements depend on: Sacral development (sacral ratio), muscle quality, rectum proprioception
• Constipation (most common problem; low ARMs; good muscle mechanism): High-fibre diet; laxatives; osmotic agents; enemas
• Faecal incontinence (high ARMs, poor sacrum): Constipating diet + daily enema program (antegrade via Malone appendicostomy or retrograde) to achieve "pseudo-continence" - socially continent
• Malone Antegrade Continence Enema (MACE/Malone procedure): Appendix brought to skin as continent catheterisable channel (umbilicus or RIF); antegrade enema via catheter; excellent social continence for incontinent patients
• Biofeedback: For patients with voluntary contraction but poor coordination
• Sphincter reconstruction / graciloplasty: Rarely needed

• Urinary incontinence (associated urological anomalies)
• Sexual dysfunction (disruption of pelvic nerves)
• Psychological impact - body image, soiling; psychological support essential
• Tethered spinal cord - may require neurosurgical release
• Long-term surveillance - annual follow-up for function, growth, quality of life

---

Summary - Marks Strategy

---

HBB-9096 | M.S. (Branch-I) General Surgery Paper-I | June 2023

Detailed Standard Textbook Answers

---

Q.1 Lymphovascular Anatomy of Stomach + Merits/Demerits and Method of D2 Gastrectomy (30 Marks)

PART A: Lymphovascular Anatomy of Stomach

Arterial Supply

1. Left gastric artery (LGA) - largest and most important; arises directly from coeliac axis; runs in lesser omentum along lesser curvature; anastomoses with right gastric artery; gives oesophageal branches
2. Right gastric artery (RGA) - branch of hepatic artery proper (or common hepatic/left hepatic); runs retrograde along lesser curvature

---

Venous Drainage

1. Left gastric (coronary) vein → portal vein (directly); important in portal hypertension - forms gastroesophageal varices when portal pressure rises; the coronary vein is the main vessel ligated in emergency surgery for bleeding varices
2. Right gastric vein → portal vein directly
3. Right gastroepiploic vein → superior mesenteric vein (SMV)
4. Left gastroepiploic vein → splenic vein
5. Short gastric veins → splenic vein
6. Prepyloric vein of Mayo - small constant vein across pyloroduodenal junction; surgical landmark to identify the pylorus

• Gastro-oesophageal junction: left gastric (portal) ↔ azygos/hemiazygos (systemic) → oesophageal/gastric varices
• Clinically: Varices at GOJ; bleeding gastric varices (especially fundal - supplied by short gastric/left gastroepiploic → splenic vein)

---

Lymphatic Drainage of Stomach

• D1: Perigastric stations (1-6 for distal gastrectomy; 1-7 for total gastrectomy)
• D2: D1 + stations 7, 8a, 9, 10, 11p, 11d, 12a (and 4sa/4sb in total gastrectomy)
• D3/extended D2: Adds stations 13, 14v, 15, 16 (para-aortic) - increased morbidity; not routinely recommended

1. Zone I (Paracardiac/lesser curvature zone): Upper lesser curvature → stations 1,2,3 → left gastric nodes
2. Zone II (Pyloric/infrapyloric zone): Antrum/pylorus → stations 5,6 → right gastric + right gastroepiploic nodes → hepatic nodes
3. Zone III (Coeliac zone): Follows short gastric/splenic → stations 4sa, 4sb, 10, 11 → splenic hilum → coeliac
4. Zone IV (Hepatoduodenal zone): Follows hepatic artery → stations 8,12 → hepatoduodenal nodes

---

Nerve Supply

• Anterior vagal trunk (left vagus): Anterior surface of oesophagus → anterior (hepatic) and gastric branches (Latarjet nerve to antrum/pylorus); "crow's foot" distribution on antrum
• Posterior vagal trunk (right vagus): Posterior surface → posterior gastric branches + coeliac branch (80% of posterior vagal fibers to coeliac plexus)

---

PART B: D2 Gastrectomy - Merits, Demerits, and Method

Definition

---

Merits of D2 Gastrectomy

1. Superior staging accuracy: Retrieval of minimum 15-25 nodes (vs <15 in D1) → more accurate N staging; avoids stage migration; JGCA recommends ≥16 nodes
2. Potentially superior oncological outcomes:
   • Japanese series: 5-yr survival significantly higher than Western D1 series (Stage II: 72% vs 29%; Stage III: 44% vs 13% - Schwartz's 11e)
   • Dutch DGCT trial (long-term 15-year follow-up): D2 superior to D1 for gastric cancer-related death rate and local recurrence (21% vs 29%); originally published in 1999 showed higher D2 morbidity, but 15-year data favored D2
   • D2 without pancreatosplenectomy achieves good survival with acceptable morbidity
3. Removal of occult nodal disease: 30-40% of patients with N0 disease on pre-op staging have positive D2 nodes; these are removed therapeutically
4. Reduced local/locoregional recurrence: Cleaner surgical field; removes regional micrometastases
5. Allows accurate N-staging for adjuvant therapy decisions: Pathological N-stage determines need for chemotherapy/chemoradiation
6. Standard resection enables meaningful comparison in clinical trials and audit

---

Demerits / Disadvantages of D2 Gastrectomy

1. Higher operative morbidity: Historically 20-30% (vs 12% D1) - but largely attributable to splenectomy + distal pancreatectomy which are NO LONGER routine
2. Higher operative mortality: Original Dutch/MRC trials showed D2 mortality 10-13% vs D1 4-6%; now modern series: <3% in specialist centres
3. Longer operative time: 4-6 hours for total gastrectomy + D2
4. Greater blood loss (mean 600-1000 mL)
5. Longer hospital stay and ICU admission
6. Complications specific to D2:
   • Pancreatic fistula (if distal pancreatectomy done)
   • Splenic complications (if splenectomy done)
   • Bile duct injury (12a dissection)
   • Injury to portal vein, hepatic artery (12a dissection)
   • Duodenal stump leak
   • Anastomotic leak
7. Requires specialist expertise: Learning curve; outcomes volume-dependent (high-volume centre definition: >20 gastric cancer resections/year)
8. No clear RCT survival benefit over D1 in Western patients (MRC/Dutch trials): However, methodological issues (including pancreatosplenectomy and lack of expertise) likely confounded results; long-term Dutch data now supports D2

---

Method / Steps of D2 Gastrectomy

Pre-operative Assessment and Preparation

1. Staging CT chest/abdomen/pelvis; EUS; laparoscopy (rule out peritoneal disease before laparotomy)
2. Nutritional assessment + optimization (albumin >30 g/dL ideal; immunonutrition 5-7 days pre-op)
3. Cardiopulmonary assessment; optimization of comorbidities
4. DVT prophylaxis, antibiotic prophylaxis, VTE stockings
5. Informed consent: reconstruction type, stoma possibility, conversion

Position and Incision

• Position: Supine; arms extended; slight head-up
• Incision: Midline laparotomy (xiphisternum to umbilicus, extending below if needed); or upper midline; Chevron (bilateral subcostal) for obese/wide patients

Step 1 - Exploration and Assessment

• Systematic inspection: liver (metastases), peritoneum (implants), omentum, nodes
• Laparoscopic staging (preferred): Before laparotomy, diagnostic laparoscopy to exclude peritoneal disease (CT misses ~25% of peritoneal disease); peritoneal washings for cytology
• Assessment of resectability: aortic invasion, hepatic artery, superior mesenteric vein involvement

Step 2 - Greater Omentum and Gastroepiploic Dissection

1. Omentectomy: Greater omentum detached from transverse colon (infracolic approach); the transverse mesocolon peritoneum overlying the pancreas is entered; this is part of D2 dissection
2. Right gastroepiploic vessels identified at their origin from GDA; lymph nodes (station 6 - infrapyloric) dissected; right gastroepiploic artery ligated and divided at origin from GDA
3. Left gastroepiploic vessels divided near splenic hilum (station 4sb, 4sa cleared); short gastric vessels divided (stations 4sa) if total gastrectomy
4. Spleen: Preserved in D2 (unless invaded or station 10 hilum nodes clearly positive) - reduces morbidity significantly

Step 3 - Pyloroduodenal Dissection and Hepatoduodenal Ligament

1. Kocherization of duodenum: Lateral duodenum mobilized; infrapyloric nodes cleared
2. Right gastric artery identified at origin from proper hepatic artery; station 5 (suprapyloric) nodes cleared; RGA ligated and divided
3. Duodenum transected 2-3 cm distal to pylorus; linear cutting stapler (TA/GIA); oversew duodenal stump (two-layer)
4. Hepatoduodenal ligament (station 12a) dissection:
   • Skeleton the hepatoduodenal ligament: hepatic artery, portal vein, bile duct
   • Station 12a (left hepatoduodenal) cleared
   • Caution: Identify all biliary anatomy (accessory hepatic ducts, low cystic duct) before dissection

Step 4 - Lesser Curvature and Left Gastric Pedicle

1. Lesser omentum divided from right gastric arch to oesophagogastric junction (OGJ) (total gastrectomy) or mid-lesser curvature (distal gastrectomy)
2. Left gastric artery dissection (station 7, 8a, 9):
   • Peritoneum over coeliac axis lifted
   • Left gastric artery identified at origin from coeliac axis
   • Station 7 (along LGA), 8a (anterior common hepatic artery), 9 (around coeliac axis) cleared en-bloc
   • Left gastric artery and vein ligated and divided at coeliac axis
3. Paracardiac dissection (stations 1, 2):
   • Right (station 1) and left (station 2) paracardial nodes cleared
   • Oesophageal hiatus exposed; oesophagus encircled if total gastrectomy

Step 5 - Splenic Artery Dissection (D2 component)

1. Station 11p (proximal splenic artery): Dissect along superior border of pancreas; proximal splenic artery skeletonised; lymph nodes removed
2. Station 11d (distal splenic artery): If splenic preservation, dissect toward hilum; nodes removed
3. Station 10 (splenic hilum): If spleen preserved (which is preferred), dissect splenic hilum nodes carefully; vascular anatomy extremely variable (risk of splenic artery/vein injury)

Step 6 - Gastric Resection

• Proximal line: at junction of upper and middle thirds (leaving 5 cm to OGJ for adequate proximal margin)
• Minimum 5 cm proximal margin for intestinal type; 8 cm for diffuse type
• GIA stapler across stomach; specimen orientation and margin check

• Oesophagus transected 5 cm above tumour; EEA stapler anvil placed in oesophagus
• Specimen removed en-bloc with D2 nodes, greater and lesser omentum

Step 7 - Reconstruction

1. Billroth I (gastroduodenostomy): End-to-end gastroduodenal anastomosis; physiological (food passes through duodenum); used if stomach remnant can reach duodenum without tension; RISK: stenosis, bile reflux
2. Billroth II (gastrojejunostomy): Stapled or hand-sewn end-to-side or end-to-end gastrojejunostomy; safer; avoids tension; RISK: bile reflux gastritis, afferent loop syndrome, Roux stasis syndrome
3. Roux-en-Y reconstruction (preferred in many centres): Reduces bile reflux; 40 cm Roux limb; becoming standard especially after total gastrectomy

1. Roux-en-Y esophagojejunostomy: 40-60 cm Roux limb; circular stapled (25 mm EEA) or hand-sewn oesophagojejunostomy; jejunojejunostomy 45 cm from OEJ
2. Jejunal pouch (Hunt-Lawrence pouch): 15-30 cm J-pouch proximal Roux limb; improves meal size, nutritional outcomes; more complex
3. Jejunal interposition (Henley loop): Restores duodenal continuity; more complex

Step 8 - Closure and Drains

• One or two closed suction drains near anastomosis and duodenal stump
• Feeding jejunostomy placed (for post-operative enteral nutrition)
• Fascial closure (mass closure - looped PDS); skin

---

Post-operative Management

1. Enhanced Recovery After Surgery (ERAS) protocol: Early mobilization, early enteral feed
2. Nasojejunal tube feeding started Day 1
3. Clear liquids when bowel function returns; soft diet by Day 4-5
4. Drain amylase on Day 3 (exclude pancreatic fistula)
5. Drain bilirubin (exclude bile leak)
6. DVT prophylaxis; chest physiotherapy
7. Adjuvant chemotherapy: FLOT (perioperative) or XELOX/capecitabine adjuvant (CLASSIC trial) within 6 weeks of surgery

---

Evidence for D2 Gastrectomy

---

Q.2 Anatomy of Triangles of Neck + Significance + Cervical Lymphadenopathy (20 Marks)

PART A: Anatomy of Triangles of Neck

• Anterior triangle (medial to SCM)
• Posterior triangle (lateral to SCM)

• Superior: inferior border of mandible + mastoid process + superior nuchal line
• Inferior: clavicle + acromion + spine of scapula + T1 spinous process
• Posterior: trapezius + posterior nuchal muscles

---

I. ANTERIOR TRIANGLE

• Anterior: midline of neck
• Posterior: anterior border of SCM
• Superior: inferior border of mandible
• Base (inferior): body of mandible
• Apex: sternum

A. Submental Triangle (Unpaired - midline)

• Boundaries: Anterior bellies of both digastric muscles (sides) + hyoid bone (floor/base)
• Floor: Mylohyoid muscle
• Contents: Submental lymph nodes, small veins (form anterior jugular vein), small branches of mylohyoid nerve

• Submental lymph nodes drain tip of tongue, floor of mouth, lower lip, central mandibular alveolus
• Metastatic nodal disease from floor of mouth/tongue carcinoma
• Access for submental artery flap

B. Digastric (Submandibular) Triangle

• Boundaries: Anterior belly of digastric (anterior), posterior belly of digastric (posterior), inferior border of mandible (above)
• Floor: Mylohyoid + hyoglossus muscles
• Contents:
  • Submandibular gland (major content; lies on mylohyoid superficially; deep part hooks around mylohyoid posterior border)
  • Submandibular duct (Wharton's duct - 5 cm; opens at sublingual papilla)
  • Facial artery (grooves submandibular gland; ligated in submandibulectomy) + facial vein
  • Hypoglossal nerve (XII) - crosses hyoglossus; at risk in submandibulectomy
  • Marginal mandibular branch of facial nerve (VII) - superficial to gland; at risk in incisions → lower lip weakness
  • Mylohyoid nerve
  • Submandibular lymph nodes
  • Lingual nerve (superior to hyoglossus) - hooks inferiorly around Wharton's duct

• Submandibulectomy for submandibular gland calculi/tumours
• Marginal mandibular nerve at risk → preserve by ligating facial vein below mandible (raises flap to protect nerve)
• Hypoglossal nerve at risk → tongue deviation and wasting if damaged
• Submandibular nodes: receive from lip, gum, teeth, floor of mouth, anterior tongue, nose

C. Carotid Triangle (Upper Carotid)

• Boundaries: Posterior belly of digastric (superior), anterior border of SCM (posterior), superior belly of omohyoid (inferior)
• Floor: Thyrohyoid, hyoglossus, inferior/middle constrictor
• Contents:
  • Common carotid artery bifurcates into ECA + ICA at upper border of thyroid cartilage (C3/C4 level)
  • Carotid sinus (baroreceptor; bifurcation) and carotid body (chemoreceptor; bifurcation)
  • External carotid artery (ECA) and branches: superior thyroid, lingual, facial, occipital (in the triangle)
  • Internal carotid artery (ICA) - no branches in neck
  • Internal jugular vein (IJV)
  • Vagus nerve (CN X) - between carotid and IJV in carotid sheath
  • Hypoglossal nerve (CN XII) - loops from behind IJV, crosses ECA/ICA anteriorly → tongue
  • Ansa cervicalis (C1-3) - motor to strap muscles; forms loop on IJV/carotid
  • Accessory nerve (CN XI) - crosses IJV in upper triangle
  • Glossopharyngeal nerve (CN IX) - between ICA and ECA

• Carotid endarterectomy (CEA) - approached through carotid triangle
• Central venous cannulation (IJV approach)
• Carotid body tumour excision
• Tracheostomy (low carotid triangle)
• ICA/ECA ligation for haemorrhage

D. Muscular Triangle (Lower/Strap muscle triangle)

• Boundaries: Midline, superior belly of omohyoid, anterior border of SCM
• Floor: Sternohyoid, sternothyroid
• Contents: Thyroid gland, parathyroid glands, strap muscles, trachea, oesophagus, inferior thyroid artery, recurrent laryngeal nerve

• Thyroidectomy (total, near-total, hemithyroidectomy)
• Parathyroidectomy
• Tracheostomy (2nd, 3rd, 4th rings - within this triangle)
• Cricothyrotomy (cricothyroid membrane - emergency airway)
• Laryngeal surgery

---

II. POSTERIOR TRIANGLE

• Anterior: posterior border of SCM
• Posterior: anterior border of trapezius
• Inferior: middle third of clavicle
• Roof: investing layer of deep cervical fascia + platysma
• Floor: prevertebral fascia covering: levator scapulae, splenius capitis, scalene muscles (anterior, middle, posterior)

1. Occipital triangle (larger, superior portion)
2. Supraclavicular (subclavian/omoclavicular) triangle (smaller, inferior portion)

Occipital Triangle Contents:

• Accessory nerve (CN XI) - exits SCM (pierces), crosses posterior triangle to trapezius; at risk in lymph node biopsy → shoulder drop (trapezius palsy)
• Cutaneous branches of cervical plexus (C2-C4): lesser occipital (C2), great auricular (C2,3), transverse cervical (C2,3), supraclavicular (C3,4)
• Brachial plexus (roots/trunks appear between scalenes at inferior triangle)
• External jugular vein (EJV) - crosses SCM superficially
• Occipital lymph nodes, posterior cervical lymph nodes

Supraclavicular (Subclavian) Triangle Contents:

• Subclavian artery (third part) - between scalene muscles
• Brachial plexus trunks (lower trunks)
• Thoracic duct - opens near junction of left IJV and left subclavian vein; at risk in left neck dissection → chylous fistula
• Subclavian vein (anterior to anterior scalene)
• Supraclavicular nodes (including Virchow's node - sentinel node for abdominal/thoracic malignancy)
• Transverse cervical and suprascapular vessels

---

Fasciae of the Neck (Surgical importance)

---

PART B: Cervical Lymphadenopathy - Differential Diagnosis and Management

Regional Lymph Node Levels (Memorial Sloan Kettering Classification)

---

Differential Diagnosis of Cervical Lymphadenopathy

I. Inflammatory/Infective (Most Common - especially children)

1. Reactive lymphadenitis - most common; any upper respiratory infection (tonsillitis, pharyngitis, dental infection, otitis media); tender, soft nodes; bilateral; resolves with treatment
2. Acute suppurative lymphadenitis - Staph aureus, Strep pyogenes; tender, fluctuant mass; overlying skin erythema; systemic features (fever, leukocytosis)
3. Tuberculous lymphadenitis (Scrofula) - most common extra-pulmonary TB; posterior triangle and deep cervical; firm/matted initially → soften → "collar-stud abscess" → discharging sinus; low-grade fever, night sweats, weight loss; most common cause of cervical lymphadenopathy worldwide
4. Cat scratch disease (Bartonella henselae) - history of cat scratch; tender axillary/cervical node; self-limiting; azithromycin if prolonged
5. Actinomycosis (Actinomyces israelii) - dental extraction; "woody" fibrosis; discharging sinuses with "sulphur granules"
6. Toxoplasmosis - posterior cervical; systemic fatigue; ELISA
7. Atypical mycobacteria (NTM) - children; violaceous skin; painless
8. Secondary syphilis - generalised lymphadenopathy; VDRL/RPR

---

II. Neoplastic

1. Hodgkin's Lymphoma (HL):
   • Young adults (bimodal: 20-30s and >50)
   • Cervical (70%) + mediastinal nodes; contiguous spread (predictable)
   • Rubbery, non-tender, firm; painless
   • Reed-Sternberg cells (binucleate "owl eye" nuclei) - pathognomonic
   • Types: Nodular sclerosis (most common, 60-65%), mixed cellularity, lymphocyte-predominant, lymphocyte-depleted
   • Constitutional "B" symptoms (fever, night sweats, >10% weight loss) - poor prognosis
   • Pel-Ebstein fever (cyclical) - classic
   • Alcohol-induced pain in nodes - classic but rare
2. Non-Hodgkin's Lymphoma (NHL):
   • Older patients; multiple sites; non-contiguous spread; extranodal involvement common
   • Large B-cell, follicular, mantle cell, Burkitt's, T-cell types
   • Less predictable spread; Waldeyer's ring involvement common

---

III. Other Causes

• Parotid tumours, submandibular gland tumours, parotitis

---

Management of Cervical Lymphadenopathy

History and Clinical Assessment

• Duration (acute <2 weeks = infective; >6 weeks = suspect malignancy)
• Symptoms: fever, night sweats, weight loss ("B symptoms"), sore throat, ear pain, dysphagia
• Risk factors: tobacco/alcohol (SCC), previous malignancy, TB contact, travel, cat contact, HIV risk
• Systemic: generalised vs localized; single vs multiple; ipsilateral vs bilateral

• Node characteristics: Size, consistency (soft/firm/hard/rubbery), mobility, tenderness, overlying skin
• Full ENT examination: oral cavity, tonsils, nasopharynx (mirror/endoscopy), larynx, thyroid
• Other sites: axilla, groin, liver, spleen (systemic lymphoma)

---

Investigations

1. FBC + differential: Leukocytosis (bacterial); atypical lymphocytes (EBV/viral); anaemia (malignancy)
2. ESR, CRP: Non-specific; elevated in infection/malignancy
3. LFTs, LDH: LDH elevated in lymphoma (staging/prognosis)
4. Monospot/Paul-Bunnell: EBV
5. Mantoux/IGRA: TB
6. CXR: Hilar lymphadenopathy (sarcoid, TB, lymphoma); mediastinal widening (lymphoma)
7. Throat/blood cultures, ASOT

---

Treatment

---

Q.3 Complications of Enteric Fistula and Management + Role of TPN (20 Marks)

Definition and Classification

• High output: >500 mL/24 hours (proximal small bowel; most dangerous)
• Moderate output: 200-500 mL/24 hours
• Low output: <200 mL/24 hours (distal; more likely to close spontaneously)

• Gastrocutaneous, duodenocutaneous, small bowel (jejunal/ileal), colonic
• Internal: enteroenteric, enterovesical, enterovaginal, coloduodenal

• Post-operative (most common - 75-80%)
• Crohn's disease
• Radiation enteritis
• Malignancy
• Trauma
• Diverticular disease
• Tuberculosis

---

Causes of Enteric Fistula

1. Anastomotic dehiscence (most common)
2. Inadvertent enterotomy (missed intraoperatively)
3. Iatrogenic injury (sharp/electrosurgical)
4. Drain erosion into bowel

• F - Foreign body in fistula tract
• R - Radiation damage
• I - Inflammation/Infection/IBD
• E - Epithelialisation of fistula tract (>2 weeks)
• N - Neoplasia (distal malignant obstruction)
• D - Distal obstruction
• S - Steroids (immunosuppression)

---

Complications of Enteric Fistula

1. Fluid and Electrolyte Disturbances (Most Immediate Threat to Life)

• Losses of 2-8 L/day of sodium-rich fluid
• Hypovolaemia: Tachycardia, hypotension, reduced urine output, pre-renal AKI
• Hyponatraemia, hypokalaemia, hypomagnesaemia, hypocalcaemia
• Metabolic acidosis (loss of bicarbonate-rich intestinal fluid)
• Prerenal uraemia → acute tubular necrosis if not corrected
• Can be life-threatening within hours if untreated

2. Malnutrition and Protein-Energy Deficiency

• Loss of protein, calories, vitamins, trace elements through fistula output
• Reduced oral intake (fear of increasing output; pain; nausea)
• Hypercatabolism from underlying sepsis
• Consequences: Hypoalbuminaemia (<25 g/dL) → impaired wound healing; immunosuppression; anastomotic failure
• Weight loss, muscle wasting, immune dysfunction
• Specific deficiencies: zinc (wound healing), vitamin C, B12, fat-soluble vitamins

3. Sepsis and Intra-abdominal Infection

• Most common cause of death from enterocutaneous fistula
• Intestinal contents contaminate peritoneal cavity or wound
• Peritonitis → multi-organ failure
• Intra-abdominal abscess: fever, leukocytosis, localizing signs
• Wound infection; wound breakdown
• Septicaemia; bacteraemia (gram-negative + anaerobes)
• 30-day mortality from high-output ECF with sepsis: 30-50%
• Opportunistic infections (immunocompromised from malnutrition/steroids)

4. Skin Excoriation and Wound Complications

• Chemical burn/erosion of perifistular skin from intestinal enzymes (trypsin, lipase, bile salts, pancreatic juice particularly corrosive)
• Severe pain, weeping, maceration, infection
• Skin breakdown makes appliance adherence impossible → cycle of leakage
• Secondary cellulitis, fungal infection
• Enteratmospheric fistula (open abdomen with fistula): entire wound exposed to enteral contents - extremely challenging

5. Acute Kidney Injury (AKI)

• From hypovolaemia (pre-renal) → if prolonged → tubular necrosis
• Exacerbated by aminoglycoside antibiotics, contrast agents
• NSAID avoidance essential

6. Haemorrhage

• From eroded vessels in fistula tract
• Secondary haemorrhage from infected vessel walls
• Pseudo-aneurysm erosion (aorta in colonic fistula post-aortic surgery)
• GI bleeding from associated mucosal ulceration

7. Respiratory Complications

• From immobility, malnutrition, abdominal distension
• Aspiration pneumonia (proximal fistula with regurgitation)
• ARDS in severe sepsis

8. Coagulopathy

• Vitamin K malabsorption → prolonged INR
• DIC in severe sepsis
• Thrombocytopenia

9. Short Bowel Syndrome

• If large bowel resection required to create proximal stoma or resect fistula
• Chronic intestinal failure → TPN dependence

10. Psychological and Social Impact

• Social isolation (offensive smell, uncontrolled leakage)
• Depression, anxiety; poor body image
• Unable to work; impaired relationships
• Multiple prolonged hospital admissions

---

Management of Enteric Fistula (SNAP - Bailey & Love 28e)

• S - Sepsis control + Skin protection
• N - Nutrition
• A - Anatomical assessment
• P - Planned definitive surgery

PHASE 1 - STABILISATION (First 48-72 hours)

• IV access (large-bore × 2)
• IV fluid replacement: Hartmann's/0.9% NaCl; replace measured fistula output mL for mL + maintenance
• Electrolyte replacement: K+, Mg2+, Ca2+, Phos, Na+
• Monitor: urine output >0.5 mL/kg/hr; HR; BP; electrolytes 6-12 hourly initially
• Catheter + hourly urine output

• Blood cultures; culture fistula output
• IV antibiotics: piperacillin-tazobactam (gram-negative + anaerobes)
• CT abdomen/pelvis: identify undrained collections
• Percutaneous CT/USS-guided drainage of collections (radiological drainage preferred over re-laparotomy in early phase)
• Source control paramount; do NOT re-operate for anastomotic leak in first 5-7 days (very high mortality); drain first
• Antifungal cover (fluconazole) if prolonged antibiotics/ITU/immunosuppressed

• Stoma nurse/wound care team early involvement
• Pouching system (ostomy appliance): measure and custom-cut; skin barrier paste/wafer
• Negative pressure wound therapy (NPWT/VAC): For complex wounds; controls drainage; promotes granulation
• Zinc oxide paste to surrounding skin; topical antifungals if Candida
• Keep perifistular skin dry

• Nil by mouth for high-output fistulae (reduces stimulation)
• Proton pump inhibitors (omeprazole IV) - reduce gastric secretion (proximal fistulae)
• Octreotide (somatostatin analogue) - reduces splanchnic/pancreatic/intestinal secretion; may reduce fistula output by 30-50%; dose 100-200 μg TDS SC or 25-50 μg/hr infusion; controversial (COCHRANE - insufficient evidence for routine use; may help high-output)
• H2 blockers (ranitidine) - reduce gastric secretion

---

ROLE OF TOTAL PARENTERAL NUTRITION (TPN) IN ENTERIC FISTULA

Indications for TPN in Enteric Fistula

1. High-output proximal fistula (duodenal, jejunal) where enteral feeding would increase output
2. Distal obstruction present - enteral feeding above fistula worsens output
3. Short bowel syndrome - insufficient absorptive surface
4. Severe peritonitis/abdominal sepsis - gut not functioning
5. Patient cannot tolerate enteral feeding - severe nausea, vomiting, ileus
6. Inaccessible enteral access - cannot place feeding tube distal to fistula
7. Pre-operative nutritional optimization - when surgery planned but patient malnourished (albumin <30 g/dL; surgery should be delayed 4-8 weeks; TPN bridges to surgery)

TPN Components and Administration

• Energy: 25-35 kcal/kg/day; 2000-2500 kcal/day; non-protein calories
• Glucose (50-60% of calories): 3-5 mg/kg/min maximum (avoid hyperglycaemia → insulin sliding scale)
• Lipid emulsion (20-40% of calories): Soyabean/olive/fish oil emulsions; 1-2 g/kg/day
• Amino acids (nitrogen source): 0.2-0.4 g N/kg/day; 1.5-2 g protein/kg/day
• Electrolytes: Na, K, Ca, Mg, phosphate (monitor and adjust daily)
• Vitamins: Complete multi-vitamin supplement (fat and water soluble)
• Trace elements: Zinc, selenium, copper, manganese, chromium (especially zinc 25-30 mg/day for high-output fistula)
• Insulin: Sliding scale to maintain BG 6-10 mmol/L

Benefits of TPN in Fistula Management

1. Allows bowel rest → reduces fistula output → promotes spontaneous closure
2. Corrects and maintains nutritional status → improves albumin, immune function, wound healing
3. Allows electrolyte control → replaces daily losses
4. Reduces mortality (historical mortality ~60% pre-TPN era; now 15-20%)
5. Allows time for spontaneous closure (occurs in 25-60% within 4-6 weeks on TPN/bowel rest)
6. Optimizes patient for surgery when spontaneous closure does not occur

Complications of TPN

• Insertion complications: pneumothorax, arterial puncture, haemothorax, air embolism, malposition
• Central line-associated bloodstream infection (CLABSI) - most common serious complication; Staph epidermidis, Candida; strict aseptic technique essential; bundles (Matching Michigan protocol)
• Line occlusion, thrombosis

• Hyperglycaemia (most common metabolic complication; → increased infection, poor healing) → strict insulin control
• Electrolyte imbalance: hypophosphataemia (refeeding syndrome if malnourished), hypokalaemia, hypomagnesaemia
• Refeeding syndrome: Rapid correction of malnutrition → intracellular shifts of K+, Mg2+, PO4³⁻ → cardiac arrhythmia, respiratory failure; prevent by NICE refeeding guidelines (slow initiation, thiamine before starting, monitor electrolytes)
• Hyperlipidaemia; liver dysfunction (TPN-associated liver disease/cholestasis - with prolonged TPN >2 weeks)
• Metabolic bone disease (prolonged TPN)
• Trace element deficiencies

• Gut mucosal atrophy (lack of luminal nutrients → villous atrophy, increased permeability, bacterial translocation)
• This is a strong argument for enteral nutrition where possible

TPN vs Enteral Nutrition - Evidence

• Preserves gut mucosal integrity (prevents bacterial translocation)
• Fewer infectious complications (meta-analysis: EN reduces sepsis by 40-50% vs TPN)
• Cheaper; simpler; lower catheter complications
• BUT: In high-output proximal fistula, TPN is necessary

---

PHASE 2 - INVESTIGATION/ASSESSMENT (Week 2-6)

1. Fistulogram (fistulogaphy): Contrast injected via skin opening; traces tract; identifies fistula anatomy
2. CT abdomen/pelvis: Abscesses; fistula tract; bowel anatomy
3. Small bowel follow-through (SBFT) / CT enterography: Bowel continuity; distal obstruction; Crohn's disease
4. MRCP/ERCP: If pancreatic/biliary fistula component
5. Colonoscopy/flexible sigmoidoscopy: Colonic fistulae

• Foreign body removal
• Radiological drainage of ongoing sepsis
• Treat underlying Crohn's (infliximab/biological therapy)
• Treat distal obstruction (stenting, bypass)

---

PHASE 3 - DEFINITIVE SURGERY (After 6-12 weeks)

1. Sepsis fully controlled (no undrained collections; normal inflammatory markers)
2. Nutritional status optimal (albumin >30 g/dL; BMI reasonable)
3. Fistula has failed to close spontaneously after 4-8 weeks
4. All anatomy defined

1. Fistula takedown + primary anastomosis: Gold standard when feasible; resect fistula segment; end-to-end or end-to-side anastomosis
2. Defunctioning stoma: Proximal diversion if anastomosis too risky; allows closure of distal limb
3. Bypass procedure: If takedown not feasible (radiation; dense adhesions)
4. Wide resection + immediate anastomosis: For Crohn's (segment resection)

---

Q.4 Write in Brief (30 Marks - 10 marks each)

Q.4(1) Surgical Anatomy of Thoraco-Abdominal Diaphragm and Surgical Importance (10 Marks)

Development

1. Septum transversum - central tendon; from mesoderm at C3-5 level
2. Pleuroperitoneal membranes - close pleuroperitoneal canals (failure → Bochdalek hernia)
3. Dorsal mesogastrium (mesoesophagus) - around oesophageal hiatus
4. Body wall musculature - peripheral muscular portion

---

Structure and Shape

• Musculotendinous sheet separating thoracic and abdominal cavities
• Dome-shaped: Right dome higher than left (liver pushes right dome up)
  • Right dome: 5th intercostal space (ICS) / level of 4th rib anteriorly
  • Left dome: 5th-6th ICS (lower - overlies stomach, spleen)
• Central tendon (trifoliate): Fibrous tendinous centre; no muscle; site where IVC passes through
• Peripheral muscular portion: Arises from:
  • Sternal origin: 2 slips from posterior surface of xiphoid
  • Costal origin: inner surfaces of lower 6 ribs (7-12) - interdigitates with transversus abdominis
  • Lumbar/crural origin: Right and left crura

---

Crura of Diaphragm

• Right crus (larger): Arises from L1, L2, L3 vertebral bodies and intervertebral discs; encircles oesophageal hiatus (both sides of oesophageal opening come from right crus)
• Left crus: Arises from L1, L2 vertebral bodies
• Crura form Median arcuate ligament (over aortic hiatus)
• Medial arcuate ligaments (lumbocostal arches): Over psoas major (from median arcuate to L1 transverse process)
• Lateral arcuate ligaments: Over quadratus lumborum (from L1 to 12th rib)

---

Major Openings (Foramina) - Critical Surgical Anatomy

• Left phrenic nerve: through left dome of diaphragm (muscular portion) - separate from IVC opening
• Splanchnic nerves (greater, lesser, least): Through crura / between crura and arcuate ligaments
• Sympathetic trunks: Behind medial arcuate ligament
• Hemiazygos vein: Through left crus
• Subcostal nerve and vessels: Behind lateral arcuate ligament

---

Blood Supply

• Superior surface (thoracic): Pericardiophrenic + musculophrenic arteries (from internal thoracic/internal mammary artery)
• Inferior surface (abdominal): Inferior phrenic arteries (from aorta directly; first branches of abdominal aorta) - most important
• Intercostal arteries (lower 5) also contribute

• Inferior phrenic veins → IVC
• Superior surface → azygos/hemiazygos or pericardiophrenic veins

---

Nerve Supply

• Phrenic nerve (C3, C4, C5) - "C3,4,5 keeps the diaphragm alive"
  • Motor: entire diaphragm (only motor supply)
  • Sensory: central part of diaphragm (central tendon + medial muscles)
• Lower intercostal nerves (T5-T12): Sensory only to peripheral diaphragm
• Motor: ONLY phrenic nerve; injury → ipsilateral diaphragmatic paralysis

• Subphrenic abscess
• Perforated peptic ulcer
• Haemoperitoneum
• Liver disease, splenic rupture

---

Surgical Importance of the Diaphragm

• Hiatus hernia: Most common; oesophageal hiatus enlarges; stomach herniates
  • Type I (Sliding, 95%): GOJ slides up; GORD; medical treatment; laparoscopic fundoplication if severe
  • Type II (Rolling/Para-oesophageal, rare): Gastric fundus herniates with GOJ in normal position; risk of volvulus; surgery recommended
  • Types III/IV: Mixed/complex; surgical repair
• Bochdalek hernia: Congenital posterolateral; neonatal emergency
• Morgagni hernia: Anterior (retrosternal); often asymptomatic; right-sided; repair when diagnosed

• Phrenic nerve injury: In cardiac surgery (ice cooling), cervical surgery, thyroid surgery, left neck dissection → ipsilateral hemidiaphragm paralysis → reduced respiratory reserve; paradoxical movement on CXR (sniff test)
• Phrenic nerve palsy: Elevated hemidiaphragm on CXR; fluoroscopy shows paradoxical movement on sniff test

• Access to thorax AND abdomen simultaneously
• Incision through: Left 7th/8th ICS + division of costal margin + diaphragmatic incision (radial towards aortic hiatus)
• Protects phrenic nerve by radial incision (nerve comes centrally)
• Used for: oesophagogastric junction tumours, suprarenal aortic surgery, thoracoabdominal aortic aneurysm repair, distal oesophagectomy, splenopancreatic procedures
• Closure: Interrupted strong sutures (0-PDS or 1-nylon); watertight seal; intercostal drain

• Diaphragmatic rupture: Blunt (left-sided 70%) or penetrating; herniation of abdominal viscera (stomach, colon, spleen) into chest; missed diagnosis common; diagnose on CXR (irregular diaphragm, gas in chest), CT, contrast studies; repair urgently (laparotomy/thoracotomy + reduce + primary repair with non-absorbable sutures; mesh if large)
• Penetrating trauma: "box" region (below nipple, above umbilical plane) → any wound can cross diaphragm; negative laparoscopy required if penetrating to this zone

• Collection between diaphragm and liver/spleen
• Right-sided (post-appendicectomy, cholecystectomy)
• Left-sided (post-gastrectomy, splenectomy)
• Signs: Fever, elevated hemidiaphragm, pleural effusion, shoulder tip pain
• Treatment: Percutaneous drainage (CT-guided) first; surgical drainage if fails
• "Pus somewhere, pus nowhere, pus under the diaphragm"

• Suprarenal/visceral aorta surgery requires diaphragmatic incision or retraction
• Thoracic aortic aneurysm: TEVAR (endovascular) or thoracoabdominal aortic repair (Crawford classification)

• Liver transplantation: IVC hiatus enlargement for cavoplasty
• Kidney transplantation (retroperitoneal)

---

Q.4(2) Wounds - Definition, Types, and Medico-Legal Importance (10 Marks)

Definition

---

Classification of Wounds

I. Based on Mechanism/Cause

• Caused by sharp-edged instrument (knife, glass, surgical scalpel)
• Clean, linear edges; minimal tissue destruction
• Length > depth
• Bleeds freely (blood vessels cut sharply → haemostasis by clot)
• Heals well by primary intention
• Medico-legal: Suggests sharp weapon (knife/blade); horizontal incised wounds suggest suicidal attempt on wrists; defensive wounds on palmar surface of forearms/hands (suggest victim tried to ward off attacker)

• Caused by blunt force (fall, road traffic accident, kick)
• Irregular, ragged edges with tissue bridging; contusion at margins
• Depth usually > length
• Tissue damage extends beyond skin edges
• Heals by secondary intention unless debrided and sutured
• Medico-legal: Suggests blunt trauma; typical in RTA, falls, assault with blunt object; pattern/morphology may identify weapon

• Closed injury; intact skin
• Blunt force → rupture of subcutaneous/subdermal blood vessels → extravasation of blood
• May track (doesn't indicate where force was applied)
• Bruise dating (approximate):
  • Fresh (0-24h): Red/blue
  • 1-3 days: Blue/purple
  • 3-5 days: Green
  • 5-7 days: Yellow/brown
  • Resolved (10-14 days): Faint yellow → disappears
  • NOTE: Not reliable; can vary with individual/location; courts no longer accept rigid dating
• Medico-legal: Indicates blunt trauma; distribution suggests mechanism (patterned bruising from weapon shape)

• Superficial wound; epidermis scraped/removed by friction/tangential force
• Direction of striations indicates direction of force
• Types: Scratch (linear, narrow); Graze/scrape (tangential force); Pressure abrasion (object pressed into skin)
• Medico-legal: "Nature of abrasion tells the tale" - direction of injury; marks match object pattern (tyre tread in RTA); ligature marks in strangulation

• Small entry; depth > surface dimensions
• Caused by sharp, pointed objects (needle, nail, knife thrust)
• High risk of deep injury (visceral, vascular) with minimal external findings
• Anaerobic infection risk (deep, narrow tract)
• Medico-legal: Entry wound size/shape helps identify weapon; track direction important; may not bleed externally despite severe internal injury

• Entry wound: Small, round, inverted; "abrasion collar" (Fovea) around entry; tattooing/stippling (unburnt powder), singeing at close range; stellate if contact shot (gas enters and tears tissue)
• Exit wound: Larger, irregular, everted; no abrasion collar; no tattooing
• Intermediate wounds: No exit; bullet lodged; retained
• Medico-legal: Determine range (contact, close, intermediate, distant); determine entry/exit; reconstruct trajectory; match to weapon calibre

• Clean-edged penetrating wound; knife/stabbing instrument
• Entry wound shape indicates: single-edged blade (one pointed, one blunt end); double-edged blade (both pointed ends)
• Depth cannot be estimated from surface
• Medico-legal: Vital for criminal investigations; length/shape of entry wound determines blade characteristics

• Human or animal; curved/oval mark; arch of upper and lower teeth
• Human bite: DNA evidence from saliva; forensic swab before cleaning
• Animal bites: Rabies risk; tetanus; mixed infection
• Medico-legal: Bite mark evidence in sexual assault, domestic violence, child abuse; dental impressions matched to suspect

• Thermal (flame, scald, contact), chemical, electrical, radiation
• Classified by depth: Superficial (1st degree: erythema); Partial thickness (2nd degree: blistering); Full thickness (3rd degree: insensate, pale/charred)
• Medico-legal: Pattern of burns (cigarette burns suggest deliberate; glove/stocking distribution suggests child abuse/immersion scalds); suspect non-accidental injury (NAI) in children

---

II. Based on Degree of Contamination (Surgical Classification)

III. Based on Healing

• Healing by Primary (First) Intention: Clean surgical wound; edges approximated; minimal scarring
• Healing by Secondary (Second) Intention: Wound left open; granulation tissue; contraction; more scarring; used in infected/contaminated wounds
• Healing by Third Intention (Delayed Primary Closure - DPC): Wound initially left open (day 0-4); then closed when infection controlled/granulation begins (day 4-5); compromise between primary and secondary

---

Medico-Legal Importance of Wounds

• Wounds must be documented meticulously in medico-legal cases; written description + photographs (ruler included for scale)
• MLC (Medico-Legal Case) documentation: Required when wound results from assault, RTA, suspicious circumstances, industrial accidents, sexual offences
• Description: location (in relation to anatomical landmarks), size (length × width × depth), shape, edges (regular/irregular), margins (contused/clean), floor, associated findings

• Simple hurt: Abrasions, contusions, minor lacerations; no permanent damage
• Grievous hurt (Section 320, IPC): Permanent disfiguration of face; permanent privation of sight, hearing; fracture/dislocation of bone; emasculation; endangering life; severe bodily pain

• Wound characteristics help identify weapon: incised vs lacerated vs puncture
• Shape, length, depth, margins, bridge of tissue, clothing comparison
• Firearms: Entry/exit; range estimation; trajectory

• Surgeons called as expert witnesses
• Section 164 CrPC: Surgeon's opinion as to cause of injury
• Wound age estimation: Fresh vs healed; vital reaction (bleeding, inflammation = ante-mortem); no vital reaction = post-mortem wound
• Vital reaction: Proves wound occurred when alive; haemorrhage, inflammation, healing - absent in post-mortem injury

• Healing stages help estimate when injury occurred
• Rigor mortis, algor mortis, livor mortis used with wound healing stage to estimate postmortem interval

• Suicidal: Hesitation marks (multiple parallel cuts before fatal one); typically accessible sites (wrists, neck, antecubital fossa); tentative abrasions; rarely face/back
• Homicidal: Defensive wounds (dorsum of hands, forearms); wounds on back; deep wounds; no hesitation
• Accidental: Corresponds to history; pattern matches mechanism

• Surgical wounds without valid informed consent = assault (UK civil law)
• Duty of Candour (statutory requirement) when complications occur
• Wound complications (anastomotic leak, dehiscence) → malpractice if negligence demonstrated

• Genital injuries (lacerations, ecchymoses); hymenal tears; forensic swabs (DNA, semen)
• STI screening; emergency contraception
• Chain of custody for forensic specimens

---

Q.4(3) Anatomy of Ischiorectal Fossa and Surgical Importance (10 Marks)

Definition

---

Boundaries

---

Contents

1. Ischiorectal (perianal) fat - abundant; allows distension of anal canal during defaecation; fills dead space; does NOT compress anal canal; easily traversed by infection (forming abscesses); allows passage of instruments
2. Pudendal nerve (S2, S3, S4) and internal pudendal vessels:
   • Travel in the pudendal canal (Alcock's canal) - fibrous tunnel on the lateral wall of fossa within obturator fascia
   • Alcock's canal: extends from lesser sciatic foramen to perineal body
   • Pudendal nerve branches in fossa:
     • Inferior rectal (haemorrhoidal) nerve: Crosses fossa to anal sphincter and perianal skin; motor to external sphincter; sensory to perianal skin
     • Perineal nerve: Branches to perineum, scrotum/labia, bulbospongiosus, ischiocavernosus
     • Dorsal nerve of penis/clitoris
3. Inferior rectal nerve (branch of pudendal):
   • Crosses ischiorectal fossa laterally to medially
   • AT RISK in drainage of ischiorectal abscess → damage causes faecal incontinence
   • Motor to external anal sphincter; sensory to perianal skin
4. Inferior rectal artery and vein (from internal pudendal artery/vein):
   • Cross the fossa to supply external anal sphincter and perianal skin
5. Scrotal/labial branches: Posterior scrotal (male) / labial (female) nerves cross anteriorly in fossa
6. Lymphatics: Drain to superficial inguinal nodes (perianal skin) and to inferior mesenteric nodes (above dentate line)

---

Important Extensions and Related Spaces

1. Deep postanal space: Behind anal canal between levator ani and anococcygeal ligament; connects the two ischiorectal fossae; HORSESHOE ABSCESS spreads via this space from one side to the other → requires bilateral drainage
2. Superficial postanal space: Posterior to anal canal between skin and anococcygeal body; separate from deep postanal space
3. Perianal space: Immediately surrounding anus; continuous with ischiorectal fossa
4. Intersphincteric space: Between internal and external anal sphincters; abscesses form here
5. Supralevator space: Above levator ani; separate from ischiorectal; connected via supralevator route to pelvis; pelvic abscess can present here
6. Retrorectal (presacral) space: Behind rectum, anterior to sacrum; contains developmental remnants (dermoid, teratoma)

---

Surgical Importance

1. Perianal and Ischiorectal Abscess

• Perianal abscess (most common, 60%): Subcutaneous/perianal space; presents at anal verge
• Ischiorectal abscess (20-25%): Fills ischiorectal fossa; more lateral; indurated, fluctuant; more extensive; may involve both fossae (horseshoe)
• Intersphincteric abscess (5%): Between sphincters; severe pain; no external swelling; diagnosed with EUA
• Supralevator abscess (5%): Above levator ani; septicaemia without external signs; diagnosis by CT; may arise from Crohn's/pelvic pathology; drainage directed by source

• Incision and drainage (I&D): Urgent; under GA/spinal/LA; cruciate incision; cavity deroofed; wound left open; avoid incisions too close to anal canal (risk to sphincter) or too lateral (creates long fistula tract)
• Ischiorectal abscess: Lateral incision in fossa (not too close to anal canal); cavity explored with finger; loculi broken down
• Horseshoe abscess: Bilateral ischiorectal drainage + counter-drainage through deep postanal space; or posterior midline drainage connecting both cavities

2. Fistula-in-Ano

• Intersphincteric (45%): Track in intersphincteric plane; usually perianal opening; fistulotomy safe
• Transsphincteric (30%): Crosses external sphincter; ischiorectal fossa traversed; cautious approach (sphincter damage → incontinence)
• Suprasphincteric (20%): Loops over puborectalis; usually complex; sphincter-preserving repair
• Extrasphincteric (<5%): Outside all sphincters; associated with Crohn's/pelvic pathology; very complex

• Identifying external opening of fistula (in ischiorectal fossa skin)
• Planning seton placement (through fistula tract; preserves sphincter; allows staged division)
• LIFT procedure (Ligation of Intersphincteric Fistula Tract): Approach in intersphincteric groove; locate and ligate tract there; preserves sphincter; good continence outcomes
• Flap procedures (ERAF - endorectal advancement flap)

3. Sphincter Anatomy and Continence

• External anal sphincter (EAS): Voluntary (striated); pudendal nerve (inferior rectal branch); wraps around anal canal below puborectalis; three parts: subcutaneous, superficial, deep
• Internal anal sphincter (IAS): Involuntary (smooth); continuation of inner circular muscle of rectum; maintains ~80% of resting anal tone; damaged in haemorrhoidectomy → passive soiling
• Puborectalis: Pulls anorectal junction anteriorly; maintains anorectal angle (90°)
• Damage during ischiorectal abscess drainage or fistula surgery → incontinence - major concern; always preserve sphincter

4. Pudendal Nerve Block

• Infiltrate anaesthetic at ischial spine (internal approach through vagina/rectum) where pudendal nerve leaves Alcock's canal
• Used for: perineal pain, anal pain, vulvodynia, obstetric perineal repair
• Accessible because the nerve lies within the fossa against lateral wall

5. Proctalgia Fugax / Levator Ani Syndrome

• Spasm of levator ani/puborectalis
• Severe episodic rectal pain; no anatomical cause
• Treatment: Digital massage of puborectalis through ischiorectal fossa; biofeedback; botulinum toxin

6. Perineal Body (Surgical Importance)

• At anterior boundary of ischiorectal fossa between anal canal and vaginal/urethral structures
• Perineal body: Junction of external anal sphincter, bulbospongiosus, superficial and deep transverse perinei muscles; IAS
• Damage (obstetric tear, trauma) → rectovaginal fistula; perineal descent; incontinence
• Reconstruction requires knowledge of ischiorectal fossa boundaries

7. Oncological Surgery

• Abdomino-perineal resection (APR/Miles' operation): For low rectal cancer
  • Perineal dissection through ischiorectal fossa; levator ani divided; entire anal canal and rectum removed
  • Ischiorectal fossa must be entered widely; ischioanal fat removed with specimen ("cylindrical APR" - reduces circumferential resection margin involvement; improves local control)
  • Careful to avoid pudendal nerve during dissection → preserve bladder and sexual function
  • Posterior dissection: along sacrum to presacral space
  • Fascia propria of mesorectum must be kept intact (TME - total mesorectal excision principle)

8. Imaging

• MRI perineum/pelvis: Gold standard for fistula mapping; identifies tracks, abscesses, secondary extensions, relation to sphincters
• Endoanal ultrasound (EAUS): Sphincter integrity; fistula tracks; dynamic assessment
• CT abdomen/pelvis: Supralevator abscesses; horseshoe collections

---

Summary - Marks Strategy