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Quick 10-Minute Writing Strategy Per Question

1. Definition (2-3 lines) - 1 min
2. Classification / Enumerate (bullet points or small table) - 2 min
3. Core content (phases / mechanism / pathophysiology) - 4 min
4. Management / Complications (if asked) - 2 min
5. Key named items (eponyms, formulas, scoring) - 1 min

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Key High-Yield Points to Never Miss

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Quick-Reference High-Yield Points - Trauma Paper

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MS General Surgery Exam - Burns, Damage Control, Day Surgery, Infections

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Q99 - Discuss Comprehensively the Principles, Management and Rehabilitation in a Patient with 50% Mixed Burns (2012)

DEFINITION OF 50% MIXED BURNS

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INITIAL ASSESSMENT AND RESUSCITATION

• Airway: Assess for inhalation injury (singed nasal hairs, hoarseness, stridor, carbonaceous sputum) → early elective intubation (do NOT wait for obstruction)
• Breathing: 100% O2 via non-rebreather; SpO2, CXR
• Circulation: Two large-bore IVs; draw bloods (FBC, U&E, coag, ABG, COHb, G&S); urinary catheter
• Disability: GCS, BM
• Exposure: Calculate TBSA; prevent hypothermia (warm environment, warm fluids)

• Rule of Nines (Adults): Head=9%, each arm=9%, anterior trunk=18%, posterior trunk=18%, each leg=18%, perineum=1%
• Palmar method: Patient's palm + fingers = 1% TBSA (for irregular burns)
• Lund and Browder chart (most accurate; corrects for age)

4 ml × Weight (kg) × % TBSA = Total volume in first 24h (Hartmann's/Ringer's Lactate)

• First 8h from time of burn: half the total
• Next 16h: remaining half
• Monitor: UO = 0.5 ml/kg/h (adults), 1 ml/kg/h (children)
• Colloid (albumin/FFP) added at 8-24h in some protocols

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WOUND MANAGEMENT

• Clean with chlorhexidine/povidone-iodine
• Silver sulfadiazine (Flamazine) OR silver dressings (Aquacel Ag, Mepilex Ag)
• Dressing changes every 2-3 days
• Monitor for deepening (conversion to full thickness by day 3-5)

• If no healing by 3 weeks → Split-skin grafting (SSG)
• Early tangential excision + SSG (within 48-72h for selected areas): reduces infection, shortens hospital stay

• Cannot heal spontaneously (no epithelial elements)
• Escharotomy: For circumferential full thickness burns → compartment syndrome → full-thickness longitudinal incisions through eschar (chest = cruciate; limbs = medial + lateral)
• Surgical excision (tangential or fascial):
  • Tangential excision: slice layers until viable tissue reached; more cosmetically acceptable; excessive blood loss
  • Fascial excision: excise to deep fascia; less blood loss; poor cosmesis; lymphoedema risk
• Temporary cover while awaiting definitive grafting: Allograft (cadaveric skin), xenograft (pigskin), Biobrane, Integra
• Split-skin graft: Donor site (anterior thigh/buttock/back); meshed (1:1.5 or 1:3 for large areas) to expand coverage; fixed with NPWT (-75 mmHg) to improve take

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ICU MANAGEMENT

• Monitor CVP, arterial line; avoid over-resuscitation ("fluid creep")
• Vasopressors (noradrenaline) if vasoplegic shock after 24-48h

• Ventilate with lung-protective strategy (TV 6 ml/kg, PEEP 5-8)
• Nebulised heparin + N-acetylcysteine (alternating 4-hourly) for inhalation injury
• Bronchoscopy for airway debris

• Early enteral feeding within 6h via NGT - reduces hypermetabolism, maintains gut barrier
• High protein (2-3 g/kg/day), high calorie (150% basal metabolic rate)
• Supplementation: Vitamin C, Vitamin D, zinc, glutamine
• Prevents: Curling's ulcer, bacterial translocation, muscle wasting

• No prophylactic systemic antibiotics (promotes resistance)
• Daily wound surveillance; swabs at dressing changes
• Treat on culture: Pseudomonas, MRSA, Candida most common
• Silver dressings provide topical antimicrobial cover

• Warm IV fluids, forced air warming blanket, warm theatre (28-32°C)
• Target core temperature >36°C

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REHABILITATION (Critical - Often Missed in Exam)

• Physiotherapy: Daily passive and active range of motion exercises - prevent contractures
• Occupational therapy: Splinting in functional position:
  • Hand: intrinsic plus position (MCP flexed, IP extended, thumb abducted)
  • Neck: extension
  • Axilla: abduction/external rotation
  • Elbow: extension
  • Knee: extension
• Early mobilisation: Weight-bearing as tolerated from day 2-3 post-grafting
• Compression garments: Custom-made pressure garments (25-40 mmHg); worn 23h/day for 12-18 months; reduce hypertrophic scarring; begin when wound healed

• Silicone gel sheets / silicone cream (worn with pressure garments)
• Massage therapy (prevent adhesion)
• Intralesional triamcinolone for hypertrophic scars
• Laser therapy (CO2, pulsed dye) for mature hypertrophic scars
• Surgical release for contractures (Z-plasty, skin flaps, SSG)

• PTSD screening (common in >30% TBSA burns)
• Anxiety, depression, body image issues
• Psychiatric/psychology referral
• Social worker support; return-to-work planning
• Family counselling

• Dietitian follow-up (prolonged nutritional support months post-discharge)
• Burns outpatient clinic (frequent reviews at 2 weeks, 1, 3, 6, 12 months)
• Return to school/work rehabilitation
• Peer support groups (Changing Faces, British Burns Association)

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Q100 - Management of 40% Burns in a 22-Year-Old, 50 kg Female Carrying 12 Weeks Pregnancy

UNIQUE CHALLENGES

• Physiological changes of pregnancy affect fluid distribution, cardiovascular response, drug metabolism
• Fetal viability at 12 weeks (non-viable ex utero - perimortem caesarean not relevant at this gestation)
• Teratogenic risks of medications
• Fetal wellbeing dependent entirely on maternal wellbeing
• Priority: Maternal resuscitation = fetal resuscitation (uterine blood flow = 700 ml/min; maternal shock → fetal demise)

CALCULATE FLUID REQUIREMENT

• Parkland formula: 4 × 50 × 40 = 8,000 ml Hartmann's in 24h
• First 8h from burn: 4,000 ml; next 16h: 4,000 ml
• Monitor UO: 0.5-1 ml/kg/h (higher target in pregnancy due to ↑ GFR)
• May need more fluid than standard Parkland (plasma leak ↑ in pregnancy)

AIRWAY

• Early intubation (supraglottic oedema worsens in pregnancy due to oestrogen-induced mucosal oedema)
• Rapid Sequence Induction: Avoid succinylcholine if >48h post-burn (hyperkalaemia risk from upregulated acetylcholine receptors in large burns); use rocuronium instead
• Preoxygenation: ↓ FRC in pregnancy → desaturates faster

FETAL MONITORING

• Fetal Doppler auscultation at ≥12 weeks (confirm viability)
• CTG monitoring once viable (>24 weeks) - not applicable here at 12 weeks
• Obstetric review and involvement from admission
• USS to confirm fetal viability, exclude placental injury

DRUG SAFETY IN PREGNANCY (12 Weeks = Organogenesis Complete, but Caution Still)

• Analgesia: Morphine IV (avoid NSAIDs - premature duct closure risk, though early pregnancy lower risk); paracetamol safe
• Antibiotics: Amoxicillin, co-amoxiclav safe; avoid tetracyclines (teeth/bone); avoid ciprofloxacin (cartilage); metronidazole (safe after 1st trimester)
• Topical agents: Silver sulfadiazine - generally considered safe short-term; avoid large area application long-term (silver absorption); mafenide acetate: avoid (carbonic anhydrase inhibitor → metabolic acidosis in fetus)
• Stress ulcer: Ranitidine or PPI (omeprazole - relatively safe)
• Tetanus: Tetanus toxoid safe in pregnancy
• TXA: Avoid (no safety data in pregnancy)
• Sedation/anaesthesia: Avoid ketamine in 1st trimester (theoretical teratogen); propofol short-term safe

NUTRITIONAL SUPPORT

• Hypermetabolic response worsened by pregnancy (additional 300 kcal/day baseline in pregnancy)
• High protein, high calorie enteral feeding within 6h
• Folic acid supplementation continued

WOUND MANAGEMENT

• Same principles: Silver dressings, early excision + SSG as needed
• Positioning: Left lateral tilt (15°) to prevent aortocaval compression once uterus enlarged enough - at 12 weeks uterus is at the pelvic brim, less critical but awareness important
• Compression garments: Avoid tight abdominal compression - use modified garments
• General anaesthesia for surgery: Avoid prone positioning if possible; use anaesthetic agent with good safety profile

OBSTETRIC COMPLICATIONS TO MONITOR

• Spontaneous miscarriage (especially in large burns with shock)
• Preterm labour (prostaglandins released from burn wound)
• Placental abruption (hypotension, shock)
• Fetal growth restriction (chronic uteroplacental insufficiency)
• Inform patient honestly about fetal prognosis in major burns (>60% TBSA → very poor fetal outcome)

MULTIDISCIPLINARY TEAM

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Q101 - Design Criteria and Functional Requirements of Scaffolds for Skin Tissue Engineering in Burns Management (2025)

DEFINITION

WHY SCAFFOLDS ARE NEEDED

• Large full-thickness burns exceed donor site availability for autografting
• Scaffolds bridge the gap: provide skin substitute while wounds heal
• Goal: Generate functional skin equivalent (epidermis + dermis) without scarring

IDEAL SCAFFOLD DESIGN CRITERIA (Biological)

1. Biocompatibility: Non-toxic, non-immunogenic, no inflammatory reaction; allows cell attachment and proliferation
2. Biodegradability: Degrades at a rate matching new tissue formation; breakdown products must be non-toxic
3. Porosity: High porosity (>90%) with interconnected pores:
   • Pore size 150-400 µm for fibroblast ingrowth
   • Larger pores (>300 µm) for vascularisation
   • Porosity allows nutrient/waste diffusion
4. Surface chemistry: Promotes cell adhesion; RGD (Arg-Gly-Asp) peptide sequences incorporated; fibronectin/collagen coating
5. Mechanical properties: Must withstand wound bed shear forces; yet flexible enough to conform to wound contour; elastic modulus similar to native dermis (~20 kPa)
6. Vascularisation support: Must promote angiogenesis (VEGF incorporation); without vascularisation → scaffold fails (necrosis)
7. Anti-infection: Incorporated antimicrobials (silver nanoparticles, chitosan, antibiotics); essential for burn wounds which are highly colonised

FUNCTIONAL REQUIREMENTS

1. Epidermal layer replacement: Keratinocyte culture on scaffold surface; forms barrier function (impermeable to water/bacteria)
2. Dermal layer replacement: Fibroblast-seeded scaffold; collagen synthesis; elastin production; provides tensile strength
3. Bi-layered constructs (ideal): Epidermis (keratinocytes) + dermis (fibroblasts + ECM) = full-thickness skin equivalent
4. Growth factor delivery: TGF-β, EGF, FGF, VEGF incorporated into scaffold matrix or microspheres; released in controlled manner
5. Anti-scarring properties: Minimal myofibroblast activation; reduce TGF-β1 (pro-fibrotic); favour TGF-β3 (anti-fibrotic; promotes regeneration)

SCAFFOLD MATERIALS

• Collagen (Type I) - most common; excellent biocompatibility; poor mechanical strength
• Collagen-glycosaminoglycan (Integra): FDA-approved; bilayer; bovine collagen + chondroitin-6-sulfate matrix + silicone sheet overlay
• Fibrin gel (autologous): Uses patient's own fibrin; no rejection
• Hyaluronic acid (Hyalograft): Promotes keratinocyte migration
• Chitosan: Antimicrobial; promotes healing

• PLGA (Poly lactic-co-glycolic acid): Biodegradable; tunable degradation rate
• Polyurethane: Flexible; good mechanical properties
• PCL (Polycaprolactone): Electrospun nanofibre scaffolds; high surface area

FABRICATION METHODS

• Electrospinning: Nanofibre scaffolds mimicking ECM architecture; high surface area
• Freeze-drying (lyophilisation): Creates porous 3D structure; used for collagen scaffolds
• 3D Bioprinting: Layer-by-layer deposition of bioinks (cell-laden hydrogels); allows precise architecture; printing vascular channels
• Decellularised matrices: Remove cells from donor tissue; retain ECM architecture; reseed with patient's cells (no rejection)

COMMERCIALLY AVAILABLE EXAMPLES

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Q102 - DCS and DCR (2022) / Damage Control Surgery in Critically Injured Patients / Steps of DCS / Principles of DCS and Resuscitation in Trauma / Acute Coagulopathy of Trauma (ACоT) and Rationale of DCR

DAMAGE CONTROL SURGERY (DCS) - DEFINITION AND RATIONALE

INDICATIONS FOR DCS

1. Haemodynamic criteria: SBP <90 mmHg, HR >120, refractory to resuscitation
2. Metabolic criteria: Temp <35°C, pH <7.2, lactate >5, base deficit >8, INR >1.5
3. Anatomical criteria: Major vascular injury, multiple solid organ injuries, damage to ≥2 body cavities, massive liver injury (Grade IV-V), pelvic ring disruption
4. Transfusion: >10 units pRBC in first 6h
5. Expected operative time: >90 min if definitive repair planned

THREE PHASES OF DCS

• Permissive hypotension, TXA, pelvic binder
• Call for operating theatre; activate massive transfusion protocol
• Minimum time in ED - transfer to theatre ASAP

1. Enter rapidly - large midline incision (xiphisternum to pubis)
2. Pack all four quadrants - control venous bleeding
3. Identify major bleeder - prioritise arterial over venous
4. Control haemorrhage:
   • Manual compression → packing
   • Vascular clamps (Pringle manoeuvre for liver: clamp hepatoduodenal ligament)
   • Ligation of non-essential vessels
   • Balloon occlusion (REBOA): Resuscitative Endovascular Balloon Occlusion of the Aorta - placed in Zone I/III via femoral access; temporises pelvic/abdominal haemorrhage
5. Control contamination:
   • Clamp/staple bowel perforations
   • Do NOT perform anastomosis
   • Close bile duct perforations temporarily
6. Temporary abdominal closure (TAC):
   • Bogota bag (IV bag sutured to fascia)
   • Opsite sandwich (adherent film + suction)
   • VAC-Pack (negative pressure TAC): most effective; manages oedema, prevents fascial retraction
7. Transfer to ICU

• Active rewarming to >36°C
• Correct acidosis: adequate resuscitation, sodium bicarbonate if pH <7.1
• Correct coagulopathy: 1:1:1 + cryoprecipitate + TXA; TEG/ROTEM guided
• Vasopressors as needed
• Nutritional support
• Target for re-operation: Temp >36°C, pH >7.35, INR <1.5, Lactate <2

• Re-look at 24-48h; remove packs; check viability
• Definitive bowel anastomosis / stoma
• Vascular reconstruction
• Fascial closure (primary if abdominal wall compliant; component separation if needed)
• If cannot close: planned hernia; biological mesh

• After weeks-months of recovery

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Q103 - Day Care Surgery: Role/Principles, Advantages, Disadvantages, Indications, Contraindications (2008)

DEFINITION

HISTORICAL BACKGROUND

• Nicoll (1909): First described day surgery in children (Glasgow)
• UK: NHS Day Surgery target - 75% of elective procedures as day cases
• Basket procedures: Standardised list of day-case procedures

PRINCIPLES

1. Patient selection based on medical fitness and social circumstances
2. Full pre-operative assessment in advance (nurse-led pre-assessment clinic)
3. Standardised anaesthetic protocols (short-acting agents, regional anaesthesia)
4. Adequate postoperative analgesia provided on discharge (multimodal)
5. Written discharge instructions + emergency contact number
6. Responsible adult escort and home supervision for 24h

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ADVANTAGES

• Avoids prolonged hospital stay (→ less nosocomial infection, DVT, deconditioning)
• Less psychological disturbance (especially children - remain in familiar environment)
• Faster return to normal activities
• Better patient satisfaction
• Less disruption to family/work

• More efficient use of surgical beds (frees inpatient beds)
• Reduces waiting lists
• Lower cost per procedure
• Reduces hospital-acquired infections

• Economic benefit: less time off work
• More efficient healthcare utilisation

DISADVANTAGES

• Not suitable for all patients or procedures: Comorbid, high-risk patients excluded
• Complications occurring at home: No immediate medical supervision
• Social criteria requirement: Need suitable home, companion, phone, transport
• Less time to educate patient pre/post-operatively
• Unplanned admissions disrupt day surgery list (overbooking)
• Limited to certain procedure durations (<90-120 min)

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SELECTION CRITERIA / INDICATIONS

• ASA I or II (ASA III - selected, well-controlled cases)
• BMI <35 (some centres accept up to 40 with anaesthetic review)
• Adult (18+ years); children with parental supervision
• No severe obstructive sleep apnoea
• No malignant hyperthermia history
• Controlled comorbidities (hypertension, diabetes, asthma)

• Responsible adult at home for 24h
• Access to telephone
• Transport home arranged (not public transport)
• Home within reasonable distance of hospital (varies: 30-60 min)
• Adequate home facilities

• Expected operative time <90-120 min
• Low risk of major haemorrhage
• Pain controllable with oral analgesia
• No requirement for prolonged IV medications

• Inguinal/femoral hernia repair (laparoscopic or open)
• Haemorrhoidectomy
• Varicose vein surgery (endovenous laser, stripping)
• Laparoscopic cholecystectomy
• Circumcision / vasectomy
• Carpal tunnel release
• Tonsillectomy / adenoidectomy
• Cataract surgery
• Excision of skin lesions / breast lump (wide local excision)
• Laparoscopic sterilisation
• Flexible/rigid endoscopy

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CONTRAINDICATIONS

• ASA IV/V
• Procedures requiring postoperative ICU/HDU admission
• Major haemorrhage risk (major vascular, complex abdominal)
• Patient lives alone with no carer
• Patient refuses or unable to comply with day surgery requirements
• Active systemic infection
• Malignant hyperthermia susceptible (without trigger-free anaesthetic protocol)

• Morbid obesity (BMI >40)
• OSAS (especially requiring CPAP)
• Poorly controlled diabetes (HbA1c >8.5)
• Extremes of age
• Anticipated difficult airway
• Previous adverse anaesthetic reaction
• Complex social circumstances

DISCHARGE CRITERIA (Modified Aldrete Score or PADSS)

• Vital signs stable; fully oriented
• Minimal nausea/vomiting; tolerating oral fluids
• Pain controlled with oral analgesia
• Walked with minimal assistance
• No excess bleeding; wound satisfactory
• Written instructions given; escort present

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Q104 - How Has COVID-19 Pandemic Affected Surgical Training? (2021)

IMPACT ON SURGICAL TRAINING

• Cancellation of elective surgery: 80-90% of elective lists cancelled during peak waves → dramatically reduced operative exposure for trainees
• Redeployment: Surgical trainees redeployed to ICU, COVID wards, emergency rotas → loss of surgical training time
• Theatre closures: Staff illness, PPE shortages, ventilator redistribution → fewer available lists
• Outpatient clinic reduction: Telephone/virtual consultations replaced in-person clinical encounters → reduced clinical assessment skills development

• ARCP (Annual Review of Competence Progression) suspended/modified → trainees' progression delayed
• Simulation-based training introduced to compensate (low-fidelity initially)
• eLogbook cases fell dramatically: studies showed 50-70% reduction in operative numbers
• Exam sittings postponed (MRCS, FRCS → moved online or delayed)
• Educational supervisors overworked → reduced supervision quality

• Virtual/online learning: Webinars, virtual masterclasses, online conference attendance (globally accessible)
• Simulation training expanded: laparoscopic box trainers, VR simulators, cadaveric workshops
• Video-assisted learning: Recording of operations for asynchronous review
• Research activity increased: Many trainees used downtime for audit, research, publications
• Accelerated transition to minimally invasive surgery (reduces theatre time, faster recovery - beneficial for COVID times)
• International collaboration in surgical education

• JCST (Joint Committee on Surgical Training): Extended training time for affected cohorts; introduced COVID-19 year
• RCS England: Published guidance on return to training; competency-based assessment rather than case numbers
• Simulation credits toward ARCP portfolio

• Backlog of cases (10+ million patients on NHS waiting list post-COVID) = increased surgical volume expected
• Risk of undertrained cohort entering independent practice
• Mental health impact on trainees: burnout, anxiety, career uncertainty
• Workforce: COVID exposure deaths in surgical staff (especially low/middle-income countries)

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Q105 - Post-Exposure Prophylaxis (PEP) for HIV: What Is It and How Is It Implemented? (2018)

DEFINITION

MECHANISM

• HIV requires integration into host CD4+ T-cell DNA (reverse transcription → integration)
• PEP drugs interrupt this process before systemic dissemination
• Window: Viral replication at site of exposure for 24-48h before lymph node seeding → systemic dissemination at 72-120h
• PEP must be started within 72 hours (the sooner, the better)

RISK STRATIFICATION BY EXPOSURE TYPE

HIGH-RISK EXPOSURES WARRANTING PEP

• Needlestick / sharps injury from known HIV+ source
• Blood/high-risk fluid splash to mucous membrane or broken skin from HIV+ source
• Unprotected sexual intercourse (rape, consensual)

IMPLEMENTATION - STEP BY STEP

• Needlestick: Wash with soap + water; allow to bleed freely; do NOT suck or apply bleach
• Eye splash: Irrigate with saline/clean water for 15 min
• Mouth splash: Spit out, rinse with water
• Report immediately to occupational health/A&E

• Source patient HIV status: known positive / unknown / low risk
• Type of exposure: percutaneous vs mucous membrane
• Volume of blood involved, hollow bore vs solid needle
• Viral load of source (if known)

• Truvada (tenofovir disoproxil fumarate 300 mg + emtricitabine 200 mg) OD
• Plus raltegravir 400 mg BD (integrase inhibitor)
• Alternative: Tenofovir + emtricitabine + lopinavir/ritonavir

• Baseline HIV test (source and recipient)
• HBV and HCV serology baseline
• FBC, renal and liver function (tenofovir nephrotoxic; monitor)
• If source HIV positive and high viral load → start immediately, do not wait for results

• HIV test at 6 weeks, 12 weeks post-exposure (3 months negative = cleared in most cases; 6 months for certainty if HCV co-infection)
• Counselling and support throughout
• Adherence support (nausea = most common side effect; antiemetics help)

• Safe sex until confirmed negative
• Review of needlestick incident; report to OH
• HBV vaccination if not immune

EFFICACY

• 81% reduction in HIV transmission with PEP (observational data)
• Efficacy approaches 100% if started within 2h and completed

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Q106 - HIV/AIDS and Surgeon/Healthcare Worker (2008, 2021)

EPIDEMIOLOGY

• Global: ~38 million people living with HIV; sub-Saharan Africa most affected
• UK: ~100,000 PLHIV; MSM and sub-Saharan African migrants most affected groups
• Occupational risk: Healthcare workers - risk per needlestick with HIV+ blood = 0.3%

PATHOPHYSIOLOGY (Brief)

• HIV = Retrovirus; infects CD4+ T lymphocytes via gp120-CD4 binding (co-receptors: CCR5, CXCR4)
• Reverse transcriptase converts RNA → DNA → integrates into host genome
• CD4+ depletion → cell-mediated immunity failure → opportunistic infections + malignancies
• AIDS defined as: CD4 count <200 cells/µL OR AIDS-defining illness

SURGICAL IMPLICATIONS

• Universal Precautions (applies to ALL patients, not just known HIV+):
  • Double gloving (reduces needlestick exposure by 60-87%)
  • Eye protection (visor/goggles)
  • Waterproof gown
  • Minimise sharps; "no-touch" technique (use instruments, not fingers, to hold needles)
  • Use blunt needles where possible
  • Announce "sharps passing" verbally
  • Dispose in sharps bin immediately
  • Single surgeon technique (only one person in wound at a time)
• HIV+ patients can undergo elective and emergency surgery
• Pre-operative: Know CD4 count and viral load; discuss with ID team
• Low CD4 (<200) → increased infection risk; consider prophylactic antibiotics, antifungals
• Patients on ART: Continue perioperatively (most oral - use NGT if nil-by-mouth)
• Drug interactions: HIV protease inhibitors interact with many anaesthetic agents (opioids, benzodiazepines - increased levels via CYP3A4 inhibition)
• HIV+ patients: increased risk of surgical site infection, poor healing, anaemia, thrombocytopenia, coagulopathy

• UK GMC/DH guidance: HIV+ healthcare workers who are on effective ART and have undetectable viral load (viral load <200 copies/ml on 2 consecutive occasions) may perform Exposure Prone Procedures (EPPs)
• Prior to 2013: HIV+ HCW excluded from EPPs; now policy changed
• EPPs = procedures where worker's blood might contact patient's open tissues (surgery, dentistry)
• Must be monitored by occupational health and HIV specialist
• Must maintain full compliance with ART
• Confidentiality maintained; identified to clinical lead only

AIDS-DEFINING CONDITIONS RELEVANT TO SURGERY

• Kaposi's sarcoma: HHV-8 associated; GI Kaposi may cause obstruction/haemorrhage; skin KS
• Lymphoma: NHL most common; abdominal/retroperitoneal; may present with obstruction
• CMV colitis: Haemorrhage, perforation; requires surgical management if perforation
• MAC (Mycobacterium avium complex): Retroperitoneal lymphadenopathy
• Cryptosporidial cholangitis: Biliary surgery

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Q107 - Pathophysiology of H. pylori Infection and Its Current Management (2022/2023)

ORGANISM

• Helicobacter pylori: Gram-negative, spiral-shaped, flagellated microaerophilic bacterium
• Identified by Warren and Marshall (1983) → Nobel Prize in Medicine, 2005
• Urease activity = key characteristic; hydrolyses urea → ammonia + CO2
• Transmission: Faecal-oral (most likely); person-to-person; contaminated water
• Prevalence: Up to 50% of world's population infected; higher in developing countries (80-90%)

PATHOPHYSIOLOGY

• Acid-hostile environment → H. pylori survives via:
  • Urease: Generates ammonia (alkaline) → neutralises gastric acid locally
  • Flagella: Motility to penetrate mucus layer
  • Adhesins (BabA, SabA): Attach to gastric epithelium
  • Outer membrane proteins: Evade immune clearance

• CagA (cytotoxin-associated gene A): Injected into epithelial cells → disrupts tight junctions, promotes IL-8 release (neutrophil recruitment), activates oncogenic signalling; associated with ↑↑ gastric cancer risk
• VacA (vacuolating cytotoxin A): Induces vacuole formation in epithelial cells; disrupts mitochondria; immune evasion
• Urease: Ammonia → mucosal damage + G-cell stimulation → hypergastrinaemia → ↑ acid secretion
• Lipopolysaccharide (LPS): Weak immunostimulator - allows persistent colonisation without complete elimination

1. Ammonia → antral G-cell stimulation → hypergastrinaemia → ↑ parietal cell acid secretion
2. Mucosal inflammation: Neutrophils + macrophages + lymphocytes → chronic gastritis (Type B)
3. Gastric metaplasia in duodenum → H. pylori colonises → duodenitis → duodenal ulcer
4. Antral predominant gastritis → hypersecretion → duodenal ulcer (more common in West)
5. Corpus predominant gastritis → hypochlorhydria → gastric ulcer + gastric cancer (more common in Asia)

Normal mucosa → Chronic non-atrophic gastritis → Atrophic gastritis → Intestinal metaplasia → Dysplasia → Gastric adenocarcinoma

• H. pylori drives antigen-dependent B-cell proliferation → MALT lymphoma (Mucosa-Associated Lymphoid Tissue)
• Eradication of H. pylori alone cures early (Stage IE) MALT lymphoma in 70-80% of cases

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DIAGNOSIS

• Urea Breath Test (UBT): Patient drinks 13C or 14C labelled urea → H. pylori hydrolyses → labelled CO2 detected in breath; sensitivity 95%, specificity 96%; preferred for treatment monitoring
• Stool Antigen Test (HpSA): Detects H. pylori antigens in stool; sensitivity 94%, specificity 97%; used for diagnosis + post-treatment check
• Serology (IgG): Detects past or present exposure; cannot distinguish active vs cleared infection; not for post-eradication testing; useful for epidemiological studies
• All non-invasive tests: Stop PPIs 2 weeks, antibiotics 4 weeks before testing (causes false negatives)

• Rapid Urease Test (CLO/RUT test): Biopsy placed in urease-containing gel; colour change = positive; sensitivity 90-95%
• Histology: Modified Giemsa or Warthin-Starry silver stain; definitive; identifies gastritis grade, metaplasia, dysplasia
• Culture: Gold standard for antibiotic sensitivity testing; slow; specialist labs
• PCR: Detects resistance genes (clarithromycin); increasingly used

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CURRENT MANAGEMENT (TREATMENT)

• Active peptic ulcer disease (duodenal or gastric) - MANDATORY
• Previous peptic ulcer with H. pylori
• MALT lymphoma
• Early gastric cancer (post-resection)
• Functional dyspepsia (may respond)
• Family history of gastric cancer in first-degree relative
• Long-term NSAID/aspirin use with peptic ulcer history
• WHO Class 1 carcinogen status: Some recommend treatment if incidentally found

• PPI (omeprazole 20 mg BD) + Amoxicillin (1g BD) + Clarithromycin (500 mg BD)
• Eradication rate: ~70-85% (decreasing due to clarithromycin resistance in UK ~15-20%)

• PPI (BD) + Bismuth subcitrate (120 mg QDS) + Metronidazole (400 mg QDS) + Tetracycline (500 mg QDS) × 10-14 days
• Eradication rate: 85-90%

• PPI + Amoxicillin + Clarithromycin + Metronidazole × 14 days
• Increasing use in areas of dual resistance

• Levofloxacin-based triple therapy (PPI + amoxicillin + levofloxacin × 10 days)
• Culture-guided therapy (sensitivity testing directs antibiotics)
• Rifabutin-based regimen (salvage): for repeated treatment failure

• Urea Breath Test or Stool Antigen Test: at least 4 weeks after completing therapy and 2 weeks after stopping PPI
• Endoscopy + biopsy: For gastric ulcer (to confirm healing + exclude malignancy)

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Q108 - Tetanus Prophylaxis (2008)

ORGANISM

• Clostridium tetani: Gram-positive, spore-forming, anaerobic bacillus
• Spores survive in soil, animal faeces, dust for years
• Exotoxin: Tetanospasmin (most potent bacterial toxin known; 2nd most toxic after botulinum)

PATHOPHYSIOLOGY

1. C. tetani enters wound → spores germinate in anaerobic/devitalised tissue
2. Tetanospasmin produced → travels retrograde along peripheral motor nerves → reaches spinal cord and brainstem
3. Binds to presynaptic nerve terminals → blocks release of GABA and glycine (inhibitory neurotransmitters)
4. Disinhibition of motor neurons → uncontrolled muscle contraction and spasms
5. Autonomic instability: hyperhidrosis, tachycardia, hypertension, labile BP

CLINICAL FEATURES

• Incubation: median 7 days (range 4-21 days)
• Trismus ("lockjaw"): First symptom (masseter spasm)
• Risus sardonicus: Rigid facial grimace (orbicularis oris + zygomaticus spasm)
• Opisthotonos: Arching of back (paravertebral + extensor muscle spasm)
• Respiratory arrest: Laryngeal + diaphragmatic spasm
• Spasms triggered by sound, light, touch
• Autonomic instability: Fluctuating BP, dysrhythmias, hyperpyrexia
• Types: Generalised (most common), local, cephalic, neonatal

TETANUS-PRONE WOUNDS (Bailey & Love)

• Wound >6 hours old
• Puncture/crush/avulsion wounds
• Soil/manure-contaminated wound
• Significant devitalised tissue
• Clinical evidence of infection
• Wound in immunocompromised patient

PROPHYLAXIS PROTOCOL

• Tetanus toxoid (TT): 0.5 ml IM (deltoid); full course = 3 doses at 0, 1, 2 months
• Booster every 10 years (or at time of injury if >10 years since last dose)
• UK childhood immunisation: 5-dose schedule (DTP at 2, 3, 4 months + pre-school booster at 3-5 years + teenage booster at 13-18 years) → lifelong protection in most

• Dose: 250-500 IU IM (separate site from TT)
• Provides immediate passive immunity
• Neutralises circulating toxin (but NOT toxin already bound to nerve endings)

• Thorough debridement of devitalised tissue (removes anaerobic environment)
• Irrigation + copious lavage
• Leave high-risk wounds open (delayed primary closure)
• Penicillin / metronidazole (anti-clostridial cover)

TREATMENT OF ESTABLISHED TETANUS

• ICU admission, sedation (benzodiazepines → ↑ GABA activity)
• HTIG 3,000-6,000 IU IM to neutralise unbound toxin
• Metronidazole or penicillin (kill bacteria)
• Tracheostomy + IPPV (for respiratory failure)
• Muscle relaxants (baclofen, dantrolene, magnesium)
• Autonomic instability: beta-blockers (labetalol), magnesium sulphate

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Q109 - Ascariasis (2022)

ORGANISM

• Ascaris lumbricoides (roundworm): Commonest intestinal nematode; affects 25% of world's population (1.5 billion)
• Largest intestinal nematode: up to 40-45 cm in length
• Transmission: Faecal-oral (eggs in contaminated soil → ingested → hatch in jejunum)
• Endemic: Sub-Saharan Africa, South Asia, Southeast Asia, rural tropics

LIFE CYCLE

1. Ingestion of embryonated eggs from contaminated soil/food/water
2. Larvae hatch in jejunum → penetrate intestinal wall → enter portal circulation → reach liver (via portal vein)
3. Larvae travel to lungs via systemic circulation → mature in alveoli for 2 weeks
4. Larvae migrate up tracheobronchial tree → swallowed → return to small intestine (jejunum/ileum)
5. Mature adult worms mate in small intestine; female produces 200,000 eggs/day → excreted in faeces → contaminates soil
6. Adults can aberrantly migrate into: common bile duct, pancreatic duct, appendix, stomach, nasal passages

CLINICAL FEATURES

• Dry cough, fever, dyspnoea, wheeze, haemoptysis
• CXR: Fleeting, bilateral eosinophilic infiltrates (pulmonary eosinophilia)
• Peripheral eosinophilia (↑ eosinophil count - key investigation finding)

• Most adults asymptomatic
• Children: Abdominal pain, distension, nausea, poor nutritional status, failure to thrive
• Intestinal obstruction (most dramatic presentation): Bolus of worms at terminal ileum; commonest in children; presents as acute abdomen
• Small bowel perforation (ischaemic pressure necrosis - rare)

• Worm enters common bile duct → ascending cholangitis, obstructive jaundice, intrahepatic abscesses
• Worm enters pancreatic duct → acute pancreatitis
• Worm in biliary tract → nidus for gallstone formation (eggs as nucleus)
• Worm in appendix → acute appendicitis

INVESTIGATIONS

• Eosinophilia (peripheral blood): Key finding in any stage
• Stool microscopy: Ova on stool examination (fertile eggs: thick-walled, brown, bile-stained)
• Sputum/BAL: Larvae + Charcot-Leyden crystals (in Loeffler's)
• Ultrasound abdomen: Worms as elongated linear echogenic structures in bile ducts or intestines; "whirlpool" sign for worm mass
• CXR: Transient pulmonary infiltrates
• Endoscopy/ERCP: Worm visualised in duodenum/bile duct

MANAGEMENT

• Albendazole 400 mg single dose (drug of choice; >95% efficacy)
• Mebendazole 500 mg single dose (or 100 mg BD × 3 days)
• Ivermectin 200 µg/kg single dose (alternative)
• Pyrantel pamoate 10 mg/kg single dose
• All paralyse worms → expelled in stool

• Worm may pass spontaneously
• ERCP: Extract worm from bile duct (basket/forceps); highly effective
• Antibiotics for associated cholangitis (E. coli, Klebsiella)
• Mebendazole/albendazole after extraction

• Non-operative initially: NG suction, IV fluids, piperazine citrate (paralytic agent - worms pass spontaneously in 80%)
• Surgery if: perforation, no resolution after 24-48h, ischaemia
  • Milk bolus to distal ileum → ileotomy → extract worms → close
  • Resection only if segment ischaemic/necrotic

• Sanitation improvement, hand washing
• Mass drug administration (MDA) programmes in endemic areas (annual albendazole)
• Safe food/water handling
• WHO recommends regular deworming in school-age children in endemic areas

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Q110 - Infection and Carcinogenesis (2014) - Bacterial, Viral, Helminths

INTRODUCTION

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A. BACTERIAL CARCINOGENESIS

• WHO Class 1 carcinogen (Group 1 - definite human carcinogen)
• Mechanism (Correa cascade):
  • CagA protein: activates src kinase → disrupts cell polarity, ↑ proliferation, inhibits apoptosis
  • VacA: ↑ reactive oxygen species (ROS) → DNA damage
  • Chronic inflammation → ↑ IL-1β, TNF-α, IL-8 → ↑ DNA strand breaks
  • Pathway: Chronic gastritis → Atrophic gastritis → Intestinal metaplasia → Dysplasia → Gastric adenocarcinoma
• H. pylori also: Only known bacterium classified as carcinogen

• Chronic carrier state → colonises biliary epithelium
• Produces carcinogenic metabolites (endogenous nitrosamines) from bile acid degradation
• Associated with gallbladder cancer, especially in endemic countries

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B. VIRAL CARCINOGENESIS

• High-risk types: HPV 16 (most oncogenic), HPV 18
• Mechanism:
  • E6 protein: binds and degrades p53 tumour suppressor → ↑ mutations, ↓ apoptosis
  • E7 protein: binds and inactivates Rb (retinoblastoma protein) → uncontrolled cell cycle progression (G1→S transition)
• Associated cancers: Cervical SCC (99%), anal SCC (90%), oropharyngeal SCC (70%), vulvar, vaginal, penile
• Prevention: HPV vaccine (Gardasil 9: types 6, 11, 16, 18, 31, 33, 45, 52, 58)

• HBsAg carriers: 100x higher HCC risk
• Mechanism:
  • HBx protein: transactivates cellular oncogenes; inactivates p53
  • Chronic inflammation → cirrhosis → carcinogenesis
  • HBV DNA integrates randomly into host genome → insertional mutagenesis
• Cirrhosis → HCC (annual incidence 2-5% in cirrhotic HBV patients)
• Prevention: HBV vaccination (part of universal immunisation schedule)

• Non-integrating virus (unlike HBV)
• Mechanism: NS3, NS5A, core protein → p53 and Rb dysfunction
• 80-90% of HCV infections → chronic hepatitis → cirrhosis → HCC
• Treatment: Direct-acting antivirals (DAAs) cure HCV → reduces HCC risk

• Gamma herpesvirus; infects B-lymphocytes
• Mechanism: Latent membrane proteins (LMP1, LMP2A) mimic CD40 signalling → B-cell immortalisation; EBNA proteins: inhibit apoptosis, activate NF-κB
• Burkitt's lymphoma: EBV + c-myc translocation t(8;14) → B-cell lymphoma; common in African children (co-factor: malaria)
• Nasopharyngeal carcinoma (NPC): Strong association in Chinese populations
• Post-transplant lymphoproliferative disorder (PTLD): Immunosuppression → EBV-driven B-cell proliferation

• Endothelial cell transformation
• Kaposi's sarcoma: skin + GI tract + lungs; seen in AIDS and immunosuppressed
• KSHV encodes viral FLICE-inhibitory protein (vFLIP) → ↓ apoptosis; vIL-6 → ↑ proliferation

• Tax protein: activates NF-κB, CDK inhibitors → T-cell proliferation
• Endemic: Japan, Caribbean, sub-Saharan Africa

• Neuroendocrine skin tumour; aggressive; elderly/immunocompromised

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C. HELMINTH-ASSOCIATED CARCINOGENESIS

• WHO Group 1 carcinogen
• Mechanism:
  • Eggs deposited in bladder wall → chronic granulomatous inflammation → mucosal hyperplasia → dysplasia → SCC of bladder
  • Nitrosamines generated by secondary bacterial infections in the inflamed bladder → carcinogen
  • N-nitroso compounds from eggs themselves
• SCC bladder (not TCC): Typical of schistosomiasis; differs from Western TCC
• Endemic: Egypt, sub-Saharan Africa; 20-50% bladder cancers in Egypt linked to bilharzia
• Treatment of Schistosomiasis: Praziquantel (single dose 40 mg/kg) - reduces carcinoma risk if given early

• Liver flukes; infect bile ducts via raw freshwater fish consumption
• Chronic biliary epithelial inflammation → hyperplasia → dysplasia → intrahepatic cholangiocarcinoma
• Extremely high cholangiocarcinoma rates in Thailand (Opisthorchis-endemic areas)
• Treatment: Praziquantel

• Eggs trapped in bowel wall → chronic inflammation → potential SCC/adenocarcinoma of colon

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SUMMARY TABLE - Infection and Carcinogenesis

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Quick Revision Table

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MS General Surgery Exam - Tuberculosis + Surgical Instruments and Energy Sources

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Q109 - Classify Abdominal Tuberculosis. Discuss the Role of Surgery in Abdominal Tuberculosis (2025)

ORGANISM

• Mycobacterium tuberculosis (most common); M. bovis (via unpasteurised milk - decreasing)
• Abdominal TB = 5th most common form of extra-pulmonary TB; increasing with HIV co-infection
• Prevalence: Endemic in South Asia, Africa, Southeast Asia

CLASSIFICATION OF ABDOMINAL TUBERCULOSIS

1. Gastrointestinal TB (most common) - ileocaecal region (80%)
2. Tuberculous lymphadenitis - mesenteric lymph nodes; retroperitoneal nodes
3. Peritoneal TB (tuberculous peritonitis)
4. Solid organ TB - hepatic, splenic, pancreatic (rare)
5. Genitourinary TB - kidney, bladder, genital tract

• Wet type (ascitic): Exudative ascites; most common
• Dry/plastic type (fibrous): Dense adhesions, omental cake, matted loops; causes obstruction; "doughy abdomen"
• Mixed type

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PATHOLOGY

• Primary: Ingestion of organisms → Peyer's patches → submucosal granuloma formation
• Granuloma = central caseating necrosis + epithelioid macrophages + Langhans giant cells + lymphocytic cuff
• Ulceration: mucosal necrosis → transverse ulcers (perpendicular to bowel axis - unlike CD which is longitudinal)
• Hyperplasia: fibrosis + thickening → stricture + mass
• Lymphatic spread → mesenteric nodes → caseation → abscess → peritoneal spread

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CLINICAL PRESENTATION

• Evening pyrexia, night sweats, weight loss, anorexia (constitutional symptoms)
• Abdominal pain (colicky or diffuse)
• Diarrhoea or alternating bowel habits
• Right iliac fossa mass (ileocaecal hyperplastic TB - commonest finding on examination)
• Distension + obstipation (obstruction)
• Ascites (peritoneal TB - shifting dullness, fluid thrill)
• "Doughy abdomen": plastic peritonitis; non-tender, doughy feel
• Complications: obstruction, perforation, fistula, bleeding (less common)

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DIAGNOSIS

• FBC: Anaemia, lymphocytosis, raised ESR and CRP
• Serum albumin: Low (chronic disease)
• Mantoux (tuberculin skin test): Positive (>10 mm in non-BCG, >15 mm in BCG-vaccinated)
• IGRA (Interferon-Gamma Release Assay - QuantiFERON-TB Gold): More specific than Mantoux; not affected by BCG; preferred test
• ADA (Adenosine Deaminase) in ascitic fluid: >30-40 U/L = strongly suggestive

• CXR: Active or healed pulmonary TB (50% of patients with abdominal TB have no pulmonary disease on CXR)
• CT Abdomen (key investigation):
  • Ileocaecal thickening, stricture
  • Mesenteric lymphadenopathy with central low-attenuation (caseation) - "rim-enhancing lymph nodes" (pathognomonic)
  • Ascites, omental thickening, peritoneal enhancement
  • Proximal bowel dilatation (obstruction)
• Barium follow-through / Small bowel study:
  • "Stierlin sign": Rapid emptying + non-filling of ileocaecal segment
  • Long narrow filling defect in terminal ileum
• USS abdomen: Lymphadenopathy, ascites, matted loops

• Colonoscopy with biopsy: Caecal/terminal ileal lesions; biopsy for histology + AFB culture
  • Findings: Ulcers (transverse), nodularity, stricture, gaping ileocaecal valve (patulous)
  • Histology: Caseating granulomas + AFB = confirmatory
  • PCR on biopsy: Highly sensitive and specific

• Exudate (protein >3 g/dL, SAAG <1.1 g/dL)
• Lymphocytic predominance (>300 cells/mm³)
• ADA >30-40 U/L
• AFB smear (low sensitivity 0-3%) and culture (sensitivity 20-45%; takes 6-8 weeks)
• Laparoscopic biopsy of peritoneum: definitive (sensitivity >95%)

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MEDICAL TREATMENT (First Line)

• Intensive phase (2 months): Rifampicin + Isoniazid + Ethambutol + Pyrazinamide (2RHEZ)
• Continuation phase (4 months): Rifampicin + Isoniazid (4RH)
• Pyridoxine (Vit B6) added to prevent INH-neuropathy
• Response: Constitutional symptoms resolve in 2-4 weeks; mass regresses in 2-3 months

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ROLE OF SURGERY IN ABDOMINAL TUBERCULOSIS

1. Intestinal obstruction: Complete/acute = emergency; incomplete = may respond to medical therapy first (trial of ATT for 4-6 weeks if subacute)
2. Perforation + peritonitis: Emergency laparotomy; rare (TB ulcers perforate less often than CD)
3. Abscess formation: Intraabdominal/psoas abscess not responding to ATT → surgical or CT-guided drainage
4. Fistula: Internal or external TB fistula not healing on ATT
5. Haemorrhage: Rare; conservative first; surgery if uncontrolled
6. Failure to respond to adequate ATT (diagnostic uncertainty): Resection to exclude malignancy or CD

• Stricture causing chronic obstruction not resolving on ATT
• Diagnostic uncertainty (Crohn's vs TB vs malignancy)
• Plastic/fibrous peritonitis with severe adhesion obstruction

• Ileocaecal resection (resection of terminal ileum + caecum + ascending colon + mesentery) with primary anastomosis - if well-nourished, non-emergency
• Right hemicolectomy: More extensive disease or mass with lymph node involvement
• Short-circuit (bypass): Ileotransverse anastomosis - only if resection not possible (frozen abdomen, poor condition)
• Strictureplasty: For multiple skip strictures (Finney or Heineke-Mikulicz type); preserves bowel length; controversial in TB (concern: leaves active disease)

• Resection + primary anastomosis (if bowel ends healthy, patient stable)
• Resection + stoma (ileostomy/colostomy) if contaminated field, poor patient condition

• Laparoscopy (diagnostic + therapeutic): Peritoneal biopsy + adhesiolysis; less morbid than laparotomy
• Laparotomy for adhesion obstruction

• Continue ATT perioperatively
• Nutritional optimisation pre-op (often severely malnourished)
• Immunocompromise assessment (HIV status)
• Cover with corticosteroids if inflammatory response severe (paradoxical reactions)

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Q110 - Clinical Presentation and Diagnosis of Abdominal Tuberculosis (2019)

CLINICAL PRESENTATION - ORGANISED BY SYSTEM

• Fever (evening pyrexia) + night sweats
• Anorexia + weight loss + cachexia
• Anaemia + malaise

• Ileocaecal TB: RIF pain (colicky), RIF mass, alternating diarrhoea/constipation
• Peritoneal TB: Abdominal distension (ascites), diffuse pain, "doughy abdomen"
• Obstruction: Colicky pain, vomiting, constipation, distension
• Perforation: Acute abdomen (rare)

• RIF mass (firm, slightly tender - ileocaecal hyperplastic TB)
• Shifting dullness / fluid thrill (ascites)
• Doughy abdomen (plastic peritonitis)
• Cervical lymphadenopathy (concurrent TB)
• Signs of pulmonary TB (signs in chest)

DIAGNOSIS TABLE

• Crohn's disease (most difficult DD)
• Carcinoma of caecum
• Appendix abscess / mass
• Lymphoma
• Actinomycosis
• Amoebiasis

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Q111 - Surgical Manifestations of Abdominal Tuberculosis (2014)

SURGICAL PRESENTATIONS IN ORDER OF FREQUENCY

• Acute (complete): Secondary to stricture, adhesions from peritoneal TB, matted loops
• Subacute/Chronic: Stricture formation at ileocaecal junction; repeated episodes
• Presentation: Colicky abdominal pain, vomiting, distension, absolute constipation
• Management: Trial of ATT + conservative for subacute; emergency laparotomy for acute complete obstruction

• Hyperplastic ileocaecal TB
• Firm, non-tender or mildly tender mass
• Mimics carcinoma of caecum or appendix mass
• Must biopsy/resect to confirm TB vs. malignancy

• Caseous lymph node → liquefaction → abscess
• Sites: Mesenteric, retroperitoneal, psoas abscess
• Psoas abscess: presents as groin swelling, limp, hip flexion deformity, fever
• May drain spontaneously into bowel, skin or bladder (fistula)

• Rare (TB ulcers perforate less than typhoid or CD)
• Ulcerative TB > hyperplastic TB
• Presentation: Acute abdomen; free gas on CXR (rare - TB may be walled off)
• Management: Emergency laparotomy

• Enterocutaneous, enterovesical, enteroenteric
• Common after abscess drainage (spontaneous or surgical)
• Managed with ATT + nutritional support; surgery if persistent

• Wet type: Moderate to massive ascites; tense abdomen
• Requires paracentesis for diagnosis and symptom relief
• Dry type: Fibrous adhesions; subacute obstruction; surgical division of adhesions

• Extensive small bowel TB → mucosal damage → malabsorption
• Bacterial overgrowth (proximal to stricture)
• Short bowel syndrome (after multiple resections)

• Less common; from ulcerative TB
• Usually minor; conservative management; surgery for massive haemorrhage

• Hepatomegaly + granulomas on liver biopsy
• Splenic TB: splenomegaly; portal hypertension; rarely abscess

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Q112 - Paustian's Criteria to Diagnose Abdominal TB. Discuss Role of Surgery in TB (2020)

PAUSTIAN'S CRITERIA FOR DIAGNOSIS OF ABDOMINAL TB

1. Histological demonstration of caseating granuloma in tissue from the affected area
2. Positive AFB culture from peritoneal fluid, biopsy, or resected specimen
3. Gross pathological appearance at laparotomy/laparoscopy consistent with TB + positive histology
4. Response to ATT with resolution of disease (retrospective criterion - used when others fail)

• Radiological features consistent with abdominal TB (CT rim-enhancing nodes)
• Positive Mantoux/IGRA
• Evidence of TB elsewhere (pulmonary, cervical nodes)
• Elevated ADA in ascitic fluid
• Typical endoscopic + histological findings (non-caseating granuloma still supportive)

ROLE OF SURGERY (see Q109 above for complete list)

• Emergency: Obstruction (complete), perforation, haemorrhage → operate after brief resuscitation
• Urgent: Non-resolving obstruction on ATT, abscess not amenable to percutaneous drainage
• Elective: Diagnostic uncertainty (CD vs TB), persistent fistula after adequate ATT, strictureplasty for multiple short strictures

• Pre-operative ATT for minimum 2-4 weeks if planned elective surgery (reduces bacterial load, improves nutrition)
• If diagnosis made at laparotomy (unexpected TB): resect + send for histology + start ATT post-op
• Anastomosis safe if: patient nutritional, bowel ends well-vascularised, no peritonitis
• Always search for other TB lesions at surgery (examine all bowel, nodes, peritoneum, liver)

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Q113 - Tubercular Peritonitis (2012)

DEFINITION

PATHOGENESIS

• Routes of spread:
  1. Haematogenous (most common): From primary lung focus or reactivation
  2. Direct extension: From adjacent organs (lymph nodes, fallopian tubes, bowel)
  3. Lymphatic: From mesenteric nodes
• Peritoneal deposits → granuloma formation → exudate → ascites

TYPES

1. Wet/Ascitic type (most common): Peritoneal inflammation → exudative protein-rich ascites; miliary tubercles on parietal peritoneum and omentum
2. Dry/Plastic type (fibrous): Fibrinous exudate organises → dense adhesions between bowel loops + omentum + parietal peritoneum; "omental cake"; subacute obstruction
3. Mixed type: Features of both

CLINICAL FEATURES

• Insidious onset
• Low-grade fever, night sweats, weight loss
• Abdominal distension (ascites)
• Diffuse abdominal pain (non-specific)
• "Doughy abdomen": Classic sign of plastic type; non-tender, doughy feel (matted loops)
• Pelvic TB (females): infertility, menstrual irregularity (concurrent fallopian tube involvement)
• Presentation may mimic ovarian cancer, cirrhotic ascites, mesothelioma

INVESTIGATIONS

• Ascitic fluid:
  • Exudate (protein >3 g/dL, SAAG <1.1 g/dL, LDH high)
  • Lymphocytic pleocytosis (>300 cells/mm³)
  • ADA >30-40 U/L (sensitivity 93%, specificity 94%) - key diagnostic test
  • AFB smear: very low sensitivity
  • Culture: 20-45%; takes 6-8 weeks
• CT abdomen: Peritoneal enhancement, ascites, omental thickening, mesenteric lymphadenopathy with central necrosis, matted loops
• CA-125: Often elevated (can mimic ovarian cancer - important distinction)
• Laparoscopy (gold standard):
  • Miliary whitish/yellowish nodules on peritoneum, omentum, bowel serosa
  • "Violin string" adhesions (thin fibrinous adhesions = classic finding)
  • Biopsy: caseating granuloma (sensitivity >90-95%)

MANAGEMENT

• ATT: Standard 6-month RHEZ regimen (same as pulmonary TB)
• Corticosteroids: Prednisolone 0.5-1 mg/kg/day for 6-8 weeks; controversial but used in some centres to reduce adhesion formation and constitutional symptoms
• Response: Ascites resolves in 6-8 weeks on ATT

• Laparoscopy: Diagnostic + adhesiolysis (low morbidity)
• Laparotomy: For subacute/acute obstruction from adhesions
  • Division of adhesions
  • Bypass (if resection not possible)
  • Resection + anastomosis in selected cases
• Avoid unnecessary laparotomy in wet type (ascites resolves with ATT)

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Q114 - Staplers in Surgery (2015, 2020, 2021) - Advantages and Disadvantages

INTRODUCTION

TYPES OF SURGICAL STAPLERS

• Places 2 parallel rows of staples; does NOT cut
• Used to close/seal bowel/vessels
• Sizes: 30, 60, 90 mm; staple heights vary for tissue thickness (blue=standard/3.5mm, green=thick/4.8mm, white=vascular/2.5mm)

• Places 4 rows of staples and cuts between middle two rows simultaneously
• Used for: resection, side-to-side anastomosis
• Available: 60, 75, 100 mm

• Creates circular end-to-end or end-to-side anastomosis
• Key component: Anvil (placed in proximal bowel) + body (placed in distal bowel)
• Sizes: 21, 25, 28, 31, 33 mm diameter
• Used for: Colorectal anastomosis, oesophagogastric anastomosis (low anterior resection, oesophagectomy, gastrectomy)

• Laparoscopic/thoracoscopic version of linear cutter
• 45, 60 mm; disposable cartridges
• Used in laparoscopic colectomy, sleeve gastrectomy, Whipple's, lung resections

• Places clips and divides vessels simultaneously; used in bowel mesentery

• For skin closure; stainless steel staples; skin approximation

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ADVANTAGES OF STAPLERS

1. Speed: Faster than hand-sewn anastomosis; reduces anaesthetic time
2. Uniformity: Consistent tension on every staple; reduces ischaemia risk vs. hand-tie
3. Accessibility: Enables anastomosis in difficult locations:
   • Ultra-low rectal anastomosis (pelvis) - impossible by hand
   • Intrathoracic oesophagogastric anastomosis
4. Leak rate: Comparable to hand-sewn (meta-analyses show no significant difference in leak rates for colorectal anastomosis)
5. Reduced infection risk: Closed technique - less bowel contamination
6. Enables minimal access surgery: Endo-GIA essential for laparoscopic resections
7. Haemostasis: Titanium staples compress tissue → better haemostasis than sutures
8. Less operator-dependent: Reduces inter-surgeon variability (standardised)

DISADVANTAGES OF STAPLERS

1. Cost: Significantly more expensive than sutures; cartridges disposable
2. Rigid learning curve: Requires training in correct deployment; misfire possible
3. Cannot be used in all tissues: Inflamed, oedematous, ischaemic, irradiated bowel - staple lines may fail
4. Staple line leak: Can occur if tissue too thick/thin for staple height chosen
5. Staple line bleeding: Requires oversewing in some cases
6. Foreign body: Titanium staples remain permanently; not biodegradable (usually not a clinical problem)
7. Inability to vary technique: Less adaptability than hand-sewn for unusual situations
8. Anastomotic stricture: Circular stapler → higher rate of anastomotic stricture (especially <25 mm)
9. Misfire / mechanical failure: Rare but catastrophic if undetected
10. Environmental waste: Large amounts of single-use plastic packaging

SPECIFIC USES (High-Yield Examples)

• Low anterior resection: Circular stapler (25-33 mm) for colorectal anastomosis
• Laparoscopic right hemicolectomy: Endo-GIA for extracorporeal or intracorporeal anastomosis
• Sleeve gastrectomy: Endo-GIA along greater curve
• Hartmann's reversal: Circular EEA stapler
• Oesophagectomy: Circular (Orvil) for cervical/intrathoracic anastomosis
• Stapled haemorrhoidectomy (PPH - Procedure for Prolapse and Haemorrhoids): Circular 33 mm stapler

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Q115 - Energy Devices in the Operation Theatre - Safe Use of Electrosurgery (2024)

INTRODUCTION

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ELECTROSURGERY / SURGICAL DIATHERMY

• Uses high-frequency alternating current (>100 kHz; typically 400 kHz - 10 MHz) to generate tissue heating
• High frequency avoids neuromuscular stimulation (neuromuscular system cannot respond to >100 kHz)
• Tissue heating → protein denaturation (coagulation) or vapourisation (cutting) depending on current density and waveform

1. Monopolar diathermy:
   • Current flows from active electrode (pencil tip) → through patient → return (indifferent) electrode (patient plate) → generator
   • Higher current density at active electrode → tissue effect; low density at plate → no effect
   • More powerful; used for most cutting/coagulation
2. Bipolar diathermy:
   • Current flows between two tips of the instrument (forceps)
   • Only tissue between the tips is affected
   • Safer: No current through body; used near vital structures (nerves, vessels)
   • Lower power; more precise

• Cutting: Continuous, low-voltage, high-frequency waveform → rapid intracellular heating → cell vapourisation → clean incision
• Coagulation: Interrupted (blended), high-voltage waveform → slower heating → protein denaturation → coagulum formation; more lateral spread
• Blend: Mixture - cutting + some haemostasis

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ADVANCED ENERGY DEVICES

• Non-contact monopolar coagulation using a flow of argon gas to conduct current to tissue
• Advantages: Uniform coagulation without char, no contact tissue adherence, coagulates over wider area
• Used for: Liver parenchyma, diffuse peritoneal bleeding, burns

• Piezoelectric transducer vibrates blade at 55,500 Hz (55.5 kHz)
• Mechanical vibration → friction → heat (50-100°C) → protein denaturation → cutting + coagulation simultaneously
• Seals vessels up to 5 mm reliably
• Advantages: No electrical current through patient; minimal lateral thermal spread (1-3 mm vs 10 mm for monopolar); less smoke; effective haemostasis; can be used near nerves safely
• Disadvantage: Blade remains hot for several seconds after activation - thermal injury risk

• Uses bipolar radiofrequency energy + pressure
• Feedback-controlled system: detects tissue impedance → automatically stops when seal complete
• Seals vessels up to 7 mm reliably; creates permanent collagen-elastin bond
• Lower temperature (70-100°C) → less thermal spread than monopolar
• Available as open, laparoscopic, and articulating versions
• Used for: thyroidectomy, colectomy, hysterectomy, splenectomy

• Radiofrequency energy ionises argon gas → plasma beam
• Precision, non-contact; coagulates, cuts, ablates at very precise depth
• Used for: Peritoneal disease, ovarian surface, mesothelioma

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SAFE USE OF ELECTROSURGERY (Bailey & Love)

1. Burns to patient (most common):
   • At return electrode (plate): Inadequate contact area, incorrect placement → current concentration → burn
   • Elsewhere: Patient touching metal objects (earthing), faulty insulation
   • Prevention: Correct plate placement (clean, dry, hair-free, well-vascularised skin), check plate contact before use, keep patient away from metal objects
2. Channelling (current concentration):
   • Current passes through narrow pedicle → concentrated → chars tissue
   • Example: Diathermy on bowel mesentery pedicle → coagulates proximal bowel
   • Prevention: Use bipolar near narrow structures; avoid monopolar on testis, penis (circumcision in children)
3. Direct coupling: Accidental activation of active electrode while touching another metal instrument → unintended coagulation; prevention: activate only when in direct tissue contact
4. Capacitive coupling (laparoscopic):
   • In laparoscopy: Metal trocar can act as capacitor; stored energy discharges to bowel
   • Occurs especially with hybrid (metal + plastic) trocars
   • Prevention: All-metal or all-plastic trocar systems; active electrode monitoring systems (AEM)
5. Insulation failure (laparoscopic):
   • Cracked insulation → current leak to adjacent structures (bowel, ureter)
   • Prevention: Inspect instruments before use; use AEM system
6. Smoke/plume:
   • Electrosurgical smoke contains carcinogens, HPV particles, viral DNA
   • Prevention: Smoke evacuation systems; N95 masks; minimise plume generation
7. Fire and explosion:
   • Alcohol prep solutions can ignite if pooled; oxygen-enriched environment
   • Prevention: Allow prep to dry; drape away from oxygen source; alert team
8. Interference with pacemakers/ICDs:
   • Monopolar diathermy can interfere with pacemakers/ICDs
   • Prevention: Use bipolar where possible; apply pacemaker magnet; liaise with cardiology; keep current path away from pacemaker
9. Surgeon burns:
   • Hole in glove → current → finger burn
   • Prevention: Double gloving; check glove integrity

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Q116 - Principles of Surgical Diathermy, Its Use, Risks, Advantages, Disadvantages, Complications (2021)

PRINCIPLES

• High-frequency AC (400 kHz - 3 MHz): Avoids neuromuscular stimulation
• Joule's Law: Heat = I² × R × t (current² × resistance × time)
• Current density: High density at small electrode tip → intense heat; low density at large plate → no tissue effect
• Cutting: Continuous wave → rapid vapourisation → sharp cut
• Coagulation: Interrupted wave → slow heating → denaturation → coagulum

USES OF DIATHERMY IN SURGERY

• Cutting through tissue (monopolar pencil)
• Haemostasis (touch/spray coagulation of small vessels)
• Sealing larger vessels with forceps (bipolar)
• Fulguration (superficial ablation of tumours - bladder papilloma, skin lesions)
• Endoscopic polypectomy (snare diathermy)
• ERCP sphincterotomy
• Laparoscopic dissection (hook, spatula)

ADVANTAGES

• Speed and efficiency of tissue division
• Simultaneous haemostasis = "blood-free" field
• Versatile (cutting + coagulation + fulguration)
• Widely available, inexpensive
• Bipolar - precise, safe near nerves
• Enables minimally invasive surgery

DISADVANTAGES

• Cannot use in explosive environments (hydrogen gas from bowel)
• Cannot use near cardiac pacemakers without precautions
• Causes tissue damage beyond intended zone (lateral thermal spread)
• Risk of unintended injury (channelling, capacitive coupling)
• Smoke production (carcinogen exposure)
• Not suitable for vessels >3 mm reliably (monopolar; need bipolar or ligature)

RISKS/COMPLICATIONS (See Q115 detailed list)

• Patient burns (plate burn, channelling, direct coupling)
• Fire and explosion
• Pacemaker/ICD interference
• Capacitive and insulation coupling in laparoscopy
• Surgeon burns (glove perforation)
• Smoke inhalation

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Q117 - Principles of Advanced Energy Devices (2022)

CATEGORIES

• Monopolar, bipolar, advanced bipolar (LigaSure, Enseal, Thunderbeat RF component)
• Heat via ionic friction (Joule heating)
• Monopolar: 400 kHz; broad effect; cutting + coagulation
• Advanced bipolar: Computer-controlled impedance feedback; seals vessels up to 7 mm; 70-100°C; minimal lateral spread

• Harmonic scalpel (Ethicon), SonoSurg, Thunderbeat ultrasonic component
• Mechanical energy → friction → heat (50-100°C); cuts + coagulates
• No electrical current in tissue; minimal thermal spread (1-3 mm)
• Protein denaturation forms white coagulum (not charring)
• Blade vibrates at 55.5 kHz; amplitude 25-100 µm

• Simultaneous ultrasonic + advanced bipolar RF
• Faster sealing + cut; wider vessel sealing range; reduced total thermal damage
• Example: Thunderbeat (Olympus) - seals up to 7 mm + cuts simultaneously in one activation

• Thermal ablation for solid tumours (liver, lung, renal)
• Microwave: 915 MHz or 2.45 GHz; dielectric heating; larger ablation zones, less affected by heat sink
• RFA: 375-500 kHz; ionic friction; requires multiple probes for large lesions

• Extreme cold (-196°C liquid nitrogen) → ice crystal formation → cell membrane disruption → necrosis
• Principle: Joule-Thomson effect (rapid gas expansion → cooling)
• Applications: Skin lesions, liver ablation, prostate (cryotherapy), retinal surgery

SELECTION PRINCIPLES FOR ENERGY DEVICES

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Q118 - Ultrasonic Dissection in Surgery - Techniques, Advantages and Disadvantages (2016)

PRINCIPLE

• Piezoelectric effect: Electrical energy → mechanical vibration of ceramic crystals in transducer → amplified by titanium blade tip → vibrates at 55,500 Hz (55.5 kHz), amplitude 25-100 µm
• Mechanical tissue effects:
  • Cavitation: Rapid vibration → rapid pressure changes → microbubble formation → cell disruption
  • Friction-generated heat: 50-100°C → protein denaturation → coagulation
  • No electrical current passes through patient

AVAILABLE DEVICES

• Harmonic Scalpel (Ethicon/Johnson & Johnson): Hook, ball, shears; most widely used
• SonoSurg (Olympus): Curved/straight blades
• Thunderbeat (Olympus): Combined ultrasonic + advanced bipolar

TECHNIQUE

1. Activate foot pedal or hand switch to engage ultrasonic vibration
2. Apply blade tip to tissue in min activation time needed
3. Use minimum power sufficient for task (reduce lateral spread)
4. Tension tissue before activation (improves cutting efficiency)
5. Allow cooling time between activations (blade retains heat 5-10 sec after deactivation - risk of delayed burn)
6. Coaptive coagulation: Tissue gently compressed between blade + tissue pad → better coagulation
7. For vessel sealing: compress vessel fully, activate at lower power for longer time

ADVANTAGES

1. No electrical current through patient → safe in patients with pacemakers/ICDs
2. Minimal lateral thermal spread (1-3 mm vs 10-15 mm for monopolar) → less collateral damage
3. Simultaneous cut and coagulation (versatile)
4. Reliable vessel sealing up to 5 mm (some devices up to 7 mm)
5. Less smoke/plume than electrosurgery → better visualisation
6. Less char formation → clearer operative field; no tissue adherence to blade
7. Safe near nerves (recurrent laryngeal, facial nerve - preferred in thyroid surgery)
8. Precise dissection in delicate anatomical planes (pancreatic dissection, retroperitoneal)
9. No electrical interference with implanted devices

DISADVANTAGES

1. Cost: More expensive than monopolar; disposable components
2. Blade remains hot (5-10 sec after deactivation) → delayed thermal injury if not careful
3. Cannot operate in blood/fluid: Efficiency reduced in blood-filled field
4. Learning curve: Different tissue handling vs conventional diathermy
5. Not as fast as monopolar for rapid large-area dissection
6. Noise and vibration: Tactile feedback reduced; some surgeons find blade "sticky"
7. Mechanical failure: Blade fracture (rare); malfunction
8. Less effective for large vessels (>7 mm): Require ligation or clip
9. Cavitation effect at blade tip: Potential for injury if used near hollow viscera

CLINICAL APPLICATIONS

• Thyroidectomy/Parathyroidectomy: Gold standard (safe near RLN, minimal thermal spread)
• Laparoscopic cholecystectomy: Cystic artery and duct dissection
• Laparoscopic colectomy/rectal surgery
• Splenectomy: Short gastric vessel division
• Pancreatectomy
• Bariatric surgery: Sleeve gastrectomy, Roux-en-Y bypass
• Thoracoscopic procedures

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Q119 - Energy Sources and Devices in Laparoscopic Surgery (2018)

SPECIFIC CONSIDERATIONS IN LAPAROSCOPY

• Limited tactile feedback
• Limited visual field (only what camera shows - 2D initially)
• Close proximity of viscera in confined space
• Trocar insulation issues

DEVICES USED IN LAPAROSCOPIC SURGERY

• Hook, spatula, scissors, needle electrodes
• Most widely used; inexpensive
• Specific laparoscopic risks: Insulation failure, capacitive coupling (see Q115)
• Use: Peritoneal dissection, appendicectomy, cholecystectomy

• Maryland bipolar forceps; bowel graspers with bipolar
• Safer than monopolar near vital structures
• No capacitive coupling risk
• Use: Near ureters, nerves, delicate vessels

• Laparoscopic sealing devices for vessels/lymphatics
• Cartridge-based; 5 mm or 10 mm port compatible
• LigaSure: Impact 5 mm (laparoscopic); Atlas 10 mm
• Seals vessels up to 7 mm; feedback-controlled
• Use: Colectomy, hysterectomy, prostatectomy, nephrectomy

• 5 mm instruments (ACE, WAVE, Focus); 10 mm ACE curved
• Most popular energy device in laparoscopic surgery
• Simultaneous cut + seal; minimal thermal spread
• Use: Thyroid, cholecystectomy, colectomy, bariatric, thoracoscopy

• 5 mm and 10 mm laparoscopic versions
• Single instrument = ultrasonic + advanced bipolar
• Fastest tissue division; highest vessel sealing capability

• Non-contact haemostasis
• Used for diffuse liver surface bleeding

SAFETY PRINCIPLES IN LAPAROSCOPIC ENERGY USE

• Inspect insulation of all instruments before use
• All-metal or all-plastic trocars (not hybrid) to prevent capacitive coupling
• Active Electrode Monitoring (AEM): Monitors current leakage; alerts surgeon to insulation failure
• Keep energy activation time minimal
• Visualise entire active electrode before activating
• "Burner up" - keep active electrode visible, not touching other instruments
• Remain alert to delayed thermal injury: Bowel injury may not be apparent intraoperatively; presents 2-7 days later with peritonitis

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Q120 - Role of LASER in Surgery (2013, 2025)

DEFINITION

PHYSICS

• Monochromatic (single wavelength), coherent (in phase), collimated (parallel) beam of light
• Stimulated emission: Energy source excites atoms in active medium → electrons jump to higher energy level → return to ground state → emit photon → stimulates other atoms → chain reaction → amplified light beam
• Components: Active medium + Energy source (pump) + Optical cavity (mirrors)

TISSUE INTERACTION MECHANISMS

1. Photothermal: Light absorbed by chromophore → heat → coagulation, ablation (most surgical use)
2. Photoablation (photochemical): UV wavelength → breaks molecular bonds directly (excimer laser in ophthalmology)
3. Photodisruption: Ultra-short pulses → plasma formation → mechanical shock wave (ophthalmic YAG)
4. Photodynamic Therapy (PDT): Photosensitiser + light → reactive oxygen species → cell death

TYPES OF SURGICAL LASERS

APPLICATIONS IN SURGERY

• Holmium laser (Ho:YAG): Urolithiasis (stone fragmentation) - flexible ureteroscopy; HOLEP (Holmium Laser Enucleation of Prostate)
• GreenLight KTP laser: Photoselective vaporisation of prostate (PVP) for BPH - "Green Light Laser Prostatectomy"
• Bladder tumour fulguration/ablation

• CO2 laser: Perianal surgery (fistula-in-ano - FILAC: FiLaC® Fistula-tract Laser Closure), haemorrhoids, anal condylomata
• Nd:YAG: Endoscopic tumour debulking (oesophageal/colonic obstruction), GI haemostasis, laparoscopic liver ablation
• PDT: Barrett's oesophagus + early oesophageal cancer, cholangiocarcinoma (biliary PDT via ERCP)

• Nd:YAG/Diode laser: Interstitial laser coagulation/ablation of liver tumours
• PDT via ERCP: Cholangiocarcinoma - photosensitiser (Photofrin) + laser → tumour ablation

• CO2/Nd:YAG TRANSANAL laser: Transanal minimally invasive surgery (TAMIS) + TEM for rectal tumours
• Laser haemorrhoidoplasty (LHP): Diode laser (980 nm) inserted into haemorrhoidal plexus → coagulation → shrinkage

• Interstitial laser ablation (ILA) for benign fibroadenoma/early cancer

• CO2 laser: Laryngeal microsurgery, glottic tumours, voice surgery, tracheal stenosis

• CO2/Er:YAG: Scar revision, resurfacing
• Pulsed dye laser: Vascular malformations, port wine stains
• Nd:YAG/diode: Hair removal, tattoo removal, skin tightening

ADVANTAGES OF LASER

• Precise, controlled tissue ablation with minimal collateral damage
• Bloodless field (simultaneous coagulation)
• Sterile technique (no tissue contact)
• Can be delivered via endoscopes/fibres (minimal access)
• PDT: tumour-selective cell kill
• Fast wound healing (CO2 laser wounds heal better than scalpel in some sites)

DISADVANTAGES

• High capital cost and maintenance
• Specific staff training required (Class IV laser = serious eye/skin hazard)
• Eye protection mandatory (patient + staff - wavelength-specific goggles)
• Fire risk (laser + drapes + oxygen)
• Laser plume: carcinogens, viral particles (HPV) - need dedicated smoke evacuator + N95 masks
• Limited to specific tissue types per wavelength
• Cannot easily be used in blood-filled field (absorption scatter)

SAFETY MEASURES

• Laser safety officer designated in every unit
• Class IV laser: Safety eyewear for all in room
• Warning signs outside laser room
• Non-reflective instruments (reduces scatter)
• Wet drapes around operative field (fire prevention)
• Smoke evacuator with 0.3 µm filter
• Laser registry (log of use, maintenance)

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Q121 - Review the Use of Indocyanine Green (ICG) and Dye in Present-Day Surgery - Applications in HPB and Colorectal Surgery (2023)

INDOCYANINE GREEN (ICG) - OVERVIEW

• ICG: Water-soluble tricarbocyanine dye; FDA-approved 1959
• Properties:
  • Molecular weight 775 Da
  • Exclusively metabolised by liver → excreted in bile (no renal excretion)
  • Near-infrared (NIR) fluorescence: Absorbs light at 750-800 nm → emits fluorescence at 830 nm (NIR spectrum)
  • NIR light penetrates tissue up to 5-10 mm
  • Safe: No radioactivity; minimal side effects (rare anaphylaxis in iodine-sensitive patients)
• Requires: NIR camera system (SPY system, Stryker 1588 NIR, Karl Storz VITOM)

MECHANISMS OF FLUORESCENCE IMAGING

• Vascular phase (0-20 min): ICG in blood → identifies vessels, perfusion in real-time
• Hepatic excretion phase (15 min - 24h): ICG excreted in bile → biliary system fluorescence (cholangiography)
• Tumour retention phase (24-48h pre-op dose): Cancer cells have impaired ICG excretion (↑ OATP1B3 + ↓ MRP2) → ICG accumulates → tumour fluoresces brightly
• Lymphatic phase: ICG injected subdermally → taken up by lymphatics → lymph node mapping (sentinel node)

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APPLICATIONS IN HPB SURGERY

• ICG given IV 30-60 min pre-operatively (0.05-0.1 mg/kg)
• Bile ducts fluoresce → visualised through NIR camera during cholecystectomy
• Identifies: CBD, cystic duct, hepatic ducts BEFORE division → reduces bile duct injuries
• Evidence: RFC reduces bile duct injury rate from 0.5% to <0.1% in laparoscopic cholecystectomy
• Critical view of safety (CVS) + RFC = gold standard for safe cholecystectomy

• ICG given IV 24-72h before hepatic resection
• Hepatocellular carcinoma (HCC), metastases (colorectal liver mets) accumulate ICG
• Intraoperative NIR imaging: Identifies lesions not visible/palpable by eye
• Detects additional unsuspected lesions in 18-30% of cases (changes surgical plan)
• Confirms complete resection (negative resection margins real-time)

• ICG injected into portal vein branch (selective) or hepatic vein
• Positive staining (portal): Identifies segment to be resected (stains orange/green)
• Negative staining (hepatic vein): Stains adjacent segment; resected segment remains dark
• Enables precise anatomical segmentectomy (Couinaud segments) - superior to ultrasound alone

• After hepatic resection, vascular reconstruction, or ALPPS
• ICG confirms adequate perfusion of liver remnant (real-time)
• Identifies ischaemic segments before closure

• After cholecystectomy or hepatic resection
• ICG in bile → fluorescence at any bile leak site
• Detects sub-clinical leaks before drain removal

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APPLICATIONS IN COLORECTAL SURGERY

• IV ICG → assesses blood supply to bowel ends at time of anastomosis
• NIR camera shows fluorescence at well-perfused anastomotic ends; dark = ischaemia
• Critical: Surgeon changes anastomotic site in 8-15% of cases when ICG used (avoiding ischaemic anastomosis)
• Evidence (PILLAR II trial): ICG reduces anastomotic leak rate (1.4% with ICG vs 6-8% historical)
• Particularly valuable in: Low anterior resection, left colectomy, Hartmann's reversal

• ICG injected submucosally around tumour (endoscopic or open)
• Lymphatics fluoresce → identify first-echelon (sentinel) nodes
• Applications: Early colon cancer (assess need for formal lymphadenectomy); personalized surgery
• D3 dissection mapping for advanced rectal cancer

• Small colonic lesions (polyps, early tumours) not palpable laparoscopically
• ICG injected colonoscopically into submucosa adjacent to lesion = tattooing with fluorescence
• Visible under NIR: Precise intraoperative localisation (superior to conventional tattoo which can spread)

• IV ICG → ureters may take up some fluorescence
• More reliable: Ureteric catheters with ICG injection → ureters fluoresce
• Prevents ureteric injury in complex pelvic surgery (rectal cancer, endometriosis resection)

• ICG injection into mesorectum → delineates lymphatic drainage
• Guides extent of mesorectal excision; lateral lymph node dissection

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OTHER DYES USED IN SURGERY

• Identifies parathyroid glands (selective uptake)
• Sentinel lymph node biopsy (breast cancer, melanoma)
• Biliary leak detection (blue in bile post-op)
• Ureteric identification

• Sentinel lymph node biopsy (breast, melanoma)
• Injected subdermally → blue dye follows lymphatics → blue sentinel node identified

• Stains dysplastic oral mucosa → detection of early oral cancer

• Chromoendoscopy - stains normal oesophagus brown; dysplasia unstained (Lugol's)

• Ophthalmology: Retinal fluorescein angiography
• Neurosurgery: 5-ALA (5-aminolevulinic acid) - glioblastoma resection (tumour fluoresces pink under violet light)

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Quick Revision Table

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MS General Surgery Exam - Sterilisation, Radiology, Orthopaedics & Compartment Syndrome

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Q122 - Sterilisation of Surgical Instruments (2009, 2024)

DEFINITIONS (Essential to State First)

• Sterilisation: Complete destruction of ALL microorganisms including bacterial spores - achieves sterility (theoretical zero probability of viable organism)
• Disinfection: Reduction of viable microorganisms to a level not harmful to health; does NOT destroy all spores
• Antisepsis: Use of chemical agents on living tissue to reduce microorganism numbers
• Decontamination: Process of removing contamination (cleaning + disinfection/sterilisation)

LEVELS OF MICROBIAL KILL

1. Sterilisation: Kills ALL including prions (high-level)
2. High-level disinfection: Kills all except some bacterial spores
3. Intermediate-level: Kills mycobacteria, most viruses, fungi, bacteria
4. Low-level: Kills most bacteria, some viruses/fungi; not mycobacteria or spores

SPAULDING CLASSIFICATION (How to Choose Level Required)

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METHODS OF STERILISATION

• Mechanism: Saturated steam under pressure → denaturation of proteins + nucleic acids
• Holding time and temperature:
  • 121°C at 15 psi (103 kPa) for 15-20 minutes (porous load)
  • 134°C at 30 psi (207 kPa) for 3 minutes (flash/unwrapped)
  • 134°C × 18 min: For prion-contaminated instruments (CJD precautions)
• Advantages: Reliable, cheap, no toxic residue, monitors available
• Limitations: Cannot be used for heat/moisture-sensitive items (plastics, optics, electronics)
• Monitoring: Chemical indicator strips (Class 1-6), biological indicators (Geobacillus stearothermophilus spores), Bowie-Dick test (air removal in pre-vacuum autoclave)

• 160°C for 2h or 180°C for 30 min
• For glassware, oils, powders (not penetrated by steam)
• Less efficient than steam; longer time; no moisture damage to heat-stable items

• Gamma irradiation (Cobalt-60): 25 kGy; industrial sterilisation of single-use disposables (sutures, syringes, catheters, implants); cold process (no heat)
• Electron beam radiation: Faster; less penetrating than gamma; used for surface sterilisation
• UV light: Surface sterilisation only (no penetration); operating theatre air/water treatment

• Temperature: 37-63°C; humidity 30-60%; concentration 450-1,200 mg/L; cycle: 2-6h
• Mechanism: Alkylation of DNA/proteins → microbial death
• Use: Heat/moisture-sensitive items - fibreoptic endoscopes, power tools, implants, electronics
• Advantages: Effective for complex devices; widely compatible
• Disadvantages: Toxic, carcinogenic, flammable; long aeration time (8-12h) to remove residue; slow cycle; strict environmental regulations
• Monitoring: Biological indicator (Bacillus atrophaeus spores)

• Low temperature (45-55°C); H2O2 vapour converted to plasma by radiofrequency
• Cycle: 28-75 min (fast); no toxic residue
• Use: Heat-sensitive instruments, endoscopes, power tools
• Cannot use: cellulose products (absorb H2O2), liquids, long narrow lumens (>30 cm, <1 mm bore)
• Increasing replacement of EtO in hospitals

• Liquid chemical sterilant (0.2% peracetic acid at 50°C for 12 min)
• For immersible heat-sensitive instruments (endoscopes)
• No toxic residue; immediate use; short cycle
• Limitation: Single-use processor; no wrapped sterile storage

• 70-80°C + 2% formaldehyde vapour
• For heat-sensitive items
• Toxic; carcinogenic; less used now

• 2% alkaline glutaraldehyde solution; immersion 3h for sterilisation; 20 min for high-level disinfection
• Used for endoscopes
• Toxic (skin, respiratory irritant); requires ventilated area; staff health issues
• Being replaced by peracetic acid and hydrogen peroxide systems

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MONITORING STERILISATION (Quality Assurance)

• Physical monitors: Temperature, pressure, time gauges - printed records
• Chemical indicators (Brownie/Bowie-Dick): Change colour when correct conditions achieved
• Biological indicators: Spore strips (Geobacillus stearothermophilus for steam; Bacillus atrophaeus for EtO); incubated after cycle; no growth = sterile
• CSSD (Central Sterile Supply Department): Track and trace system; batch records for recall if failure

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Q123 - Sterilisation of Endoscopes (2010)

UNIQUE CHALLENGES OF ENDOSCOPES

• Heat-sensitive (optical fibres, cameras, electronic components) → autoclave CANNOT be used
• Long narrow lumens (channels) → difficult to penetrate with chemical agents
• Multiple detachable components (biopsy forceps, valves)
• Risk of transmitting blood-borne viruses (HIV, HBV, HCV), Helicobacter pylori, multi-drug resistant organisms
• CJD prion risk: Variant CJD has been transmitted endoscopically (theoretical risk with flexible endoscopes)
• High throughput in busy endoscopy units → rapid turnaround required

ENDOSCOPE DECONTAMINATION SEQUENCE (MANDATORY ORDER)

• Wipe outer surface with detergent wipe
• Flush all channels with enzymatic detergent while scope still attached to patient (prevents biofilm formation)
• Do NOT allow secretions to dry (drying = biofilm in channels)

• Leak test before immersion (confirms integrity of scope)

• Immerse in enzymatic detergent solution
• Brush ALL accessible channels with appropriately sized brushes
• Flush all channels under water
• Rinse thoroughly with water
• Critical step: Removes organic material that inactivates disinfectants

• Machine cycle:
  • Wash (detergent)
  • Disinfect: 2% glutaraldehyde (20-45 min) or peracetic acid (0.35%, 5 min at 55°C) or orthophthalaldehyde (OPA, 0.55%, 5 min at 20°C) - high-level disinfection
  • Rinse with purified water (removes disinfectant residue)
  • Dry (forced air)
• Peracetic acid (NuCidex/Steris): Most widely used now; fast, effective, non-toxic
• OPA (Cidex OPA): Faster than glutaraldehyde; less toxic; cannot be used for cystoscopes (stains bladder mucosa)

• Hang vertically in clean, dry, ventilated cupboard (prevents residual water → Pseudomonas growth)
• Cap all ports
• Maximum storage time varies by policy (typically 3-7 days; rescope if exceeded)

• All re-usable accessories: Full sterilisation in autoclave (CSSD) - these are critical items (enter mucosa)

SPECIFIC PATHOGENS OF CONCERN

• Helicobacter pylori: Transmissible via endoscope; eradicated by HLD
• HCV, HBV, HIV: Inactivated by HLD
• Mycobacterium tuberculosis: Requires extended disinfection time
• Pseudomonas aeruginosa: Waterborne; grows in residual water; prevented by drying
• vCJD prions: Heat-resistant; endoscope with prion risk → quarantine until patient status confirmed; may require destruction if strongly positive

QUALITY ASSURANCE

• Microbiological sampling of endoscopes: Weekly or after confirmed outbreak
• Audit of AER cycles: Printed records retained
• Staff health: Avoid glutaraldehyde exposure (gloves + mask); OPA safer

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Q124 - Sterilisation of Laparoscopic Instruments (2014)

SPECIFIC CHALLENGES

• Complex design: Multiple joints, lumens, non-detachable components
• Metal + plastic + optical components in one instrument
• Optical telescopes (camera + light guide): Heat and moisture sensitive
• Long narrow channels (insufflation tubes, biopsy channels): Difficult to reach
• Soiling with blood, bowel content, CO2 insufflation gas residue

DECONTAMINATION SEQUENCE

• Wipe ports and cannulas
• Flush any channels at bedside immediately

• Fully disassemble all components (ports, valves, trocars, reducers)
• Ultrasonic cleaner bath for complex instruments (cavitation dislodges debris from joints/crevices)
• Manual scrubbing with brush; inspect channels under illumination
• Rinse thoroughly

• Wrap in double peel pouches or rigid container (CST trays)
• Label with batch number, date, expiry, steriliser number

• Cool, dry, clean area
• Check integrity of packaging before use
• Do not use if packaging damaged

SINGLE-USE vs REUSABLE LAPAROSCOPIC INSTRUMENTS

• Single-use (disposable): Guaranteed sterility; no reprocessing cost; higher unit cost; environmental waste
• Reusable: Cost-effective long-term; requires rigorous decontamination; risk of instrument failure and inadequate cleaning
• Trend: Single-use for complex devices (endoscopic staplers, trocars with seal); reusable for simple instruments

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Q125 - Universal Precautions in Surgery/Medicine (2009)

DEFINITION

RATIONALE

• Healthcare workers (HCW) cannot reliably identify patients with blood-borne infections
• HIV, HBV, HCV may be undiagnosed and undetectable
• Protection applies both ways: HCW → patient AND patient → HCW

PERSONAL PROTECTIVE EQUIPMENT (PPE)

• Worn for any contact with blood, body fluids, mucous membranes, non-intact skin
• Change between patients; change if torn
• Double gloving in surgery (reduces needlestick exposure 60-87%)
• Outer glove colour indicator gloves (perforation detection system)

• Fluid-resistant gown for splash risk procedures (surgery, endoscopy, delivery)
• Waterproof apron for heavy splash/contamination

• Goggles or visor: For any splash risk (surgery, ENT, endoscopy, wound irrigation, bronchoscopy)
• Full face shield for aerosol-generating procedures (AGPs)

• Surgical mask: Droplet precautions
• FFP2/FFP3 (N95/N99): Airborne precautions (TB, COVID-19, measles, influenza during AGPs)

SHARPS SAFETY (Highest Risk for Blood-Borne Virus Transmission)

• Use needles with safety mechanisms (retractable, sheathing devices)
• Never re-sheath needle by hand (one-hand scoop technique if unavoidable)
• Pass sharps in a kidney dish/neutral zone; announce "sharp passing"
• Blunt needles for suturing (peritoneum, fascia)
• Dispose in rigid sharps container immediately at point of use
• Never overfill sharps bin (>3/4 full = close and replace)

HAND HYGIENE (Single Most Important Infection Control Measure)

• WHO "5 Moments": Before patient contact, before aseptic technique, after body fluid exposure, after patient contact, after contact with patient's environment
• Alcohol hand rub: 20-30 sec; effective for most organisms
• Soap and water: When hands visibly soiled, after toileting, for Clostridium difficile (spores not killed by alcohol)
• Surgical hand scrub: Minimum 3-5 min (traditional) or 1.5-3 min (alcohol-based surgical rub)

IN THE OPERATING THEATRE

• All instruments assumed potentially contaminated until sterilised
• All patients treated as potentially infectious
• Minimum personnel in theatre during high-risk procedures
• Gown changed if contaminated intraoperatively
• "No-touch" technique: Use instruments not fingers to mount needles; blunt dissection where possible

WASTE DISPOSAL (see Q126)

• Segregation at source: clinical (yellow bags), sharps (yellow bins), cytotoxic (purple), domestic (black)

POST-EXPOSURE PROTOCOL (see Q105)

• Needlestick → wash, bleed freely, report, risk assess → PEP within 72h if indicated

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Q126 - Biological/Hospital Waste - Classification and State Methods of Disposal

DEFINITION

CLASSIFICATION OF HOSPITAL WASTE (WHO/UK HTM 07-01)

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METHODS OF DISPOSAL

• High-temperature combustion: 800-1200°C (dual-chamber incinerator)
• Destroys ALL pathogens including prions (>1000°C)
• Used for: Anatomical waste, cytotoxic waste, infectious waste
• Advantages: Complete destruction, volume reduction (>90%), energy recovery
• Disadvantages: Air pollution (dioxins, furans, heavy metals) if incomplete combustion; expensive; carbon footprint
• Modern incinerators: Secondary combustion chamber + scrubbers + bag filters (reduces pollutants)

• 134°C + pressure → destroys all pathogens (not prions)
• Pre-treatment of infectious waste before landfill
• Disadvantage: Does not destroy pharmaceuticals, cytotoxics, radioactive material

• Shreds waste + moist heat (microwave) → decontaminates
• Low volume; used for infectious waste (not sharps/pathological)

• Hypochlorite solution (bleach) 10,000 ppm: For liquid infectious waste (urine, blood, faeces)
• Formaldehyde/peracetic acid for specific applications
• Lime: For anatomical waste in low-resource settings

• Only for general/domestic waste after decontamination
• NOT for untreated clinical waste (illegal in most countries)

• Incineration at licensed facility
• Never crush/bend/resheath
• Never disposed in domestic waste

• Short half-life (e.g. Tc-99m, 6h): Store for 10 half-lives until background level → dispose as general
• Long half-life: Return to supplier or licensed radioactive waste facility
• Liquid radioactive waste: May be diluted to permissible levels and drain-disposed under licence

• Return to pharmacy for proper disposal
• Cytotoxics: Specialist incineration (>1100°C)
• NOT poured down sinks (aquatic environment contamination)

SEGREGATION PRINCIPLES

• At point of generation (bedside, theatre, clinic)
• Correct bag/bin selection by clinical staff
• Training of all staff: annual mandatory refresher
• Colour coding must be consistent (national/WHO standards)
• Never mix categories

LEGAL FRAMEWORK (UK)

• Environmental Protection Act 1990
• Health and Social Care Act 2008
• HTM 07-01: Safe Management of Healthcare Waste
• UN regulations for transport of dangerous goods (ADR)

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Q127 - Breast Ultrasound - Uses (2010)

PRINCIPLE

USES OF BREAST ULTRASOUND

• Young women <35 years (dense breast tissue on mammography - USS preferred)
• Distinguish solid vs cystic (simple cyst: anechoic, posterior acoustic enhancement, smooth walls = benign; aspirate if symptomatic)
• Characterise solid masses: Shape (wider than tall = benign), margins (irregular/spiculated = suspicious), echogenicity, acoustic shadowing

• Indeterminate mammographic findings → USS to further characterise
• Dense breast tissue (young, HRT, pregnancy): USS more sensitive than mammography
• BI-RADS classification for USS findings (1-6): Guides management

• USS-guided core biopsy (14G Trucut): Preferred for palpable + impalpable lesions
• USS-guided fine needle aspiration cytology (FNAC)
• USS-guided wire localisation (hookwire) for impalpable lesions pre-operatively
• USS-guided abscess aspiration
• USS-guided vacuum-assisted biopsy (Mammotome)

• Evaluates axillary lymph nodes in newly diagnosed breast cancer
• Normal nodes: Preserved fatty hilum, cortex <3 mm
• Suspicious: Lost fatty hilum, cortical thickening/bulge, rounded shape
• USS-guided FNA/core biopsy of suspicious axillary nodes → avoids sentinel node biopsy if positive

• Detects implant rupture (intracapsular: "snowstorm" appearance; extracapsular: free silicone)
• Preferred over MRI for initial assessment; MRI = gold standard for implant integrity

• Safe (no radiation)
• Galactocele, lactation abscess, mastitis evaluation

• Confirms glandular vs fatty tissue; excludes carcinoma

• Axillary USS: Regional lymph node assessment
• Liver USS: Distant metastasis

• Localise lesion before wide local excision
• Verify specimen adequacy (USS of specimen)

• Seroma/haematoma post-mastectomy or lumpectomy
• Wound complication assessment

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Q128 - Pre-Operative Ultrasound (2012)

USES OF USS IN PRE-OPERATIVE ASSESSMENT

• Cholecystitis/Gallstones: Murphy's sign on USS; gallbladder wall thickness >3 mm; pericholecystic fluid; stone size
• Appendicitis: Non-compressible appendix >6 mm; periappendiceal fat stranding; free fluid
• Hernia: Identifies contents, assesses reducibility, detects concurrent contralateral hernia
• AAA (Abdominal Aortic Aneurysm): Measures aortic diameter pre-repair; monitors for surveillance
• Biliary tree: CBD diameter >6 mm = dilated (choledocholithiasis); pancreatic masses

• Pre-thyroidectomy: Size, nodule characteristics, retrosternal extension
• Pre-parathyroidectomy: Localise adenoma (sensitivity 80%); combined with Sestamibi scan

• Duplex USS: Pre-operative mapping of saphenous vein (varicose vein surgery, CABG conduit)
• Carotid duplex: Pre-carotid endarterectomy; degree of stenosis
• Peripheral artery disease: ABPI + waveform analysis pre-amputation/bypass

• Renal calculi: Pre-operative planning (ESWL, PCNL, ureteroscopy)
• Obstructive uropathy: Hydronephrosis grade

• Lipoma vs abscess vs lymph node vs other
• Guides whether FNA/biopsy needed pre-operatively

• Pericardial effusion
• Left ventricular function estimate (eyeball assessment)
• IVC collapsibility (volume status assessment)

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Q129 - Small Bowel Enema (SBE) (2009, 2010)

DEFINITION

DISTINCTION FROM BARIUM FOLLOW-THROUGH

TECHNIQUE

1. NJ tube inserted under fluoroscopy or endoscopic guidance to Treitz ligament (DJ flexure)
2. Methylcellulose or dilute barium contrast injected through tube under fluoroscopic control
3. Real-time fluoroscopic images taken as contrast progresses through all segments
4. Spot images of abnormal areas

INDICATIONS

• Suspected small bowel obstruction (aetiology, site, degree)
• Crohn's disease (delineates extent of disease, strictures, skip lesions, fistulae)
• Malabsorption syndromes (coeliac - featureless jejunum; giardiasis)
• Obscure GI bleeding (after negative upper and lower endoscopy)
• Small bowel tumours (GIST, lymphoma, carcinoid, adenocarcinoma)
• Post-surgical anatomy (complications, adhesion site)
• Radiation enteropathy strictures

RADIOLOGICAL FINDINGS

• Crohn's disease: Skip lesions; "string sign of Kantor" (linear stricture of terminal ileum); cobblestoning; rose-thorn ulcers; fistulae
• Intestinal TB: Stierlin's sign; long narrow terminal ileum; non-filling caecum; patulous ileocaecal valve
• Coeliac disease: Featureless jejunum (loss of valvulae conniventes - jejunisation of ileum)
• Obstruction: Transition point; dilated proximal, collapsed distal
• Lymphoma: Aneurysmal dilatation (destruction of neural plexus)

CURRENT STATUS

• Largely replaced by CT enterography (CTE) and MR enterography (MRE):
  • No nasojejunal tube required
  • Better soft tissue assessment
  • Extraluminal disease (nodes, mesentery) visible
  • No radiation (MRE)
• Capsule endoscopy: Replaced SBE for mucosa visualisation + suspected bleeding
• SBE still used where advanced imaging unavailable

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Q130 - CT Scan (2006)

PRINCIPLE

• X-ray source rotates around patient → detectors collect attenuation data from multiple angles → computer reconstruction → cross-sectional images (tomographic slices)
• Hounsfield Units (HU): Scale of tissue density
  • Air: -1000 HU; Fat: -100 to -50 HU; Water: 0 HU; Soft tissue: +20 to +60 HU; Blood: +55-75 HU; Bone: +400 to +1000 HU

TYPES

• Plain CT (non-contrast): Haemorrhage, calcification, bone, pneumothorax
• Contrast-enhanced CT (CECT): IV contrast (iodine-based); phases:
  • Arterial phase (20-40 sec): Aorta, arterial blush, hepatic arterial anatomy
  • Portal venous phase (60-90 sec): Liver parenchyma, spleen, bowel; best for most pathology
  • Delayed phase (5-10 min): Collecting systems, bladder, slow leaks
• CT Angiography (CTA): Arterial phase; evaluates vascular anatomy, aneurysm, haemorrhage
• CT Urography (CTU): All phases; upper urinary tract

SURGICAL APPLICATIONS

• Trauma: CTCA (CT chest/abdomen/pelvis) in haemodynamically stable trauma patients; grades solid organ injuries; identifies vascular injury; evaluates all body cavities
• Bowel obstruction: Identifies level, cause (adhesion, tumour, volvulus), closed loop, ischaemia
• Appendicitis: Sensitivity 95%, specificity 98%; identifies perforation, abscess, alternative diagnosis
• Pancreatitis: CT Severity Index (Balthazar score: A-E); pancreatic necrosis (absent perfusion after IV contrast); CT at 48-72h
• AAA: Measures size, identifies rupture, leaking haematoma, dissection

• Cancer staging: Lung, bowel, liver, pancreas, gastric, renal; assesses lymph nodes, metastases, vascular invasion
• Pre-operative planning: Anatomy, anomalies, vascular relationships
• CT-guided biopsy/drainage: Percutaneous core biopsy of lesions, abscess drainage

• Fast (whole body in <30 seconds)
• High resolution; multi-planar reconstructions (MPR), 3D
• Available 24/7 in most centres
• Guides interventional procedures

• Radiation: Single abdominal CT = 8-10 mSv (equivalent ~500 CXR); cumulative concern
• IV contrast: Nephrotoxicity (AKI risk in CKD, diabetes, dehydration); anaphylaxis (premedication with steroids/antihistamine if previous reaction)
• Cannot use in pregnancy (relative CI; use if clinically essential)
• Artefact: Metal implants degrade image

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Q131 - MRI in Cancer Management

PRINCIPLE

• Radiofrequency pulses in strong magnetic field → excitation of hydrogen protons → relaxation → signal detected → cross-sectional images
• T1-weighted: Fat = bright; fluid = dark; good for anatomy, contrast-enhanced (gadolinium)
• T2-weighted: Fluid = bright; fat = intermediate; good for tumour detection (tumours have high water content = bright)
• DWI (Diffusion-Weighted Imaging): Detects restricted diffusion → malignant tissue (dense cellularity)
• DCE-MRI (Dynamic Contrast Enhancement): Tumour angiogenesis patterns

CANCER APPLICATIONS

• High-resolution MRI pelvis: Gold standard for local staging
• Assesses: T stage (T2=muscularis propria; T3=perirectal fat; T4=adjacent organs); N stage (nodes); CRM (circumferential resection margin - <1 mm = positive CRM); EMVI (extramural vascular invasion - poor prognosis); MRF (mesorectal fascia involvement)
• Guides decision: CRM threatened → neoadjuvant chemoradiotherapy before surgery
• Post-treatment restaging MRI: tmrg (tumour regression grade)

• Characterise indeterminate hepatic lesions (vs CT): Haemangioma (T2 bright = "light bulb sign"), FNH (central scar), HCC (arterial enhancement + washout), metastases
• Gadolinium-enhanced MRCP (hepatobiliary agents - Primovist): Hepatocyte-specific; HCC, cholangiocarcinoma
• Liver volume assessment pre-hepatectomy

• Non-invasive biliary/pancreatic duct imaging
• Choledocholithiasis, PSC (beaded ducts), biliary strictures, pancreatic duct pathology
• Replaced diagnostic ERCP in most cases

• Extent of disease in lobular carcinoma (notoriously occult on mammogram)
• Contralateral breast screening in high-risk (BRCA mutation carriers)
• Implant integrity assessment
• Response to neoadjuvant chemotherapy

• Base of skull invasion, perineural spread, carotid artery involvement
• Better than CT for soft tissue planes

• T2WI + DWI + DCE
• PI-RADS score 1-5 for lesion suspicion
• Pre-biopsy MRI → MRI/USS-fusion targeted biopsy (replaces systematic blind TRUS biopsy)
• Staging: ECE (extracapsular extension), SVI (seminal vesicle invasion), lymph node involvement

• Local staging; neurovascular involvement; surgical planning
• Compartment anatomy delineation

• Local extent; cervical stromal invasion; parametrial involvement; lymph nodes

• No radiation
• Superior soft tissue contrast
• Multi-parametric capability (DWI, DCE, spectroscopy)

• Slow (30-60 min per scan); claustrophobia; noise
• Cannot use: Ferromagnetic implants (old aneurysm clips, cochlear implants, pacemakers - conditional MRI now possible for some)
• Expensive; less available than CT
• Bowel motion artefact; cardiac gating required for cardiac MRI

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Q132 - Role of Endoscopic Ultrasound (EUS) in Diagnostic Evaluation (2019)

DEFINITION

ADVANTAGES

• Close proximity to target (no bowel gas interference) → high-resolution images (superior to transabdominal USS)
• Real-time guidance for needle biopsy (EUS-FNA, EUS-FNB)
• GI wall layers clearly delineated: Mucosa, muscularis mucosa, submucosa, muscularis propria, serosa

APPLICATIONS

• Pancreatic masses: Most sensitive modality (>95%) for small pancreatic tumours (<2 cm); local T-staging
• EUS-FNA/FNB: Tissue diagnosis of pancreatic masses (sensitivity 80-95%); safe alternative to surgical biopsy
• Choledocholithiasis: Detects CBD stones missed on MRCP or transabdominal USS; sensitivity ~95%
• Chronic pancreatitis: Parenchymal and ductal changes (Rosemont criteria)
• Pancreatic cysts (IPMN, MCN, SCN): Characterise; wall thickness; septations; mural nodules; malignant potential assessment; cyst fluid aspiration for CEA, amylase, cytology
• Common bile duct dilation: Identify cause

• T staging: Most accurate for T1-T4 (mucosal layer involvement determines EMR/ESD vs oesophagectomy)
• N staging: Peritumoural lymph node assessment; EUS-FNA of suspicious nodes
• Submucosal tumours (GIST, carcinoid): Origin layer, EUS-FNA for tissue

• EUS (rigid or flexible): T1-T2 staging for early rectal cancer (decides EMR/TAMIS vs TME)
• Limited depth of penetration vs MRI for T3/T4

• EUS-FNA of posterior mediastinal masses, lymph nodes (TBNA via transgastric/transoesophageal route)
• Lung cancer lymph node staging (N2, N3 disease)

• EUS-guided drainage: Pancreatic pseudocyst, walled-off necrosis (cystgastrostomy/cystoduodenostomy with lumen-apposing metal stent - LAMS)
• EUS-guided biliary drainage (EUS-BD): When ERCP fails (hepaticogastrostomy or choledochoduodenostomy)
• EUS-guided coeliac plexus block/neurolysis: Pain management in pancreatic cancer/chronic pancreatitis
• EUS-guided fiducial marker placement: For stereotactic body radiotherapy (SBRT) targeting

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Q133 - Importance of T-Tube Cholangiogram in Current Surgical Practice (2021)

T-TUBE - DEFINITION

T-TUBE CHOLANGIOGRAM - PRINCIPLE

WHEN PERFORMED

• Post-operative (Day 7-10): Before removal of T-tube
• Purpose: Confirm no retained stones, bile leak, stricture before tube removal

INFORMATION PROVIDED

1. Residual/retained CBD stones: Most important indication
2. CBD calibre and anatomy: Stricture? Post-operative narrowing?
3. Flow into duodenum: Confirms satisfactory drainage; no distal obstruction
4. Bile leaks: Contrast extravasation at anastomosis/drain site
5. Biliary anatomy: Before complex re-operation

MANAGEMENT OF RETAINED STONE ON T-TUBE CHOLANGIOGRAM

• Wait 6 weeks for fibrous T-tube tract to mature
• Then stone extraction via T-tube tract (Burhenne technique: radiological basket extraction through mature tract)
• Alternatively: ERCP + sphincterotomy + stone extraction
• Surgery only if above fail

PROCEDURE FOR T-TUBE REMOVAL

• T-tube cholangiogram at Day 7-10: If normal (no stones, good flow into duodenum)
• Remove T-tube by gentle traction
• Tract closes within 24-48h
• Do NOT remove T-tube if: Distal obstruction, retained stone, bile leak, jaundice

CURRENT RELEVANCE (2021)

• ERCP widely available: Pre-operative CBD clearance (stone detected on MRCP pre-op → ERCP first → laparoscopic cholecystectomy)
• Intraoperative cholangiography (IOC): Confirms CBD clearance at time of cholecystectomy
• Fluorescence cholangiography (ICG): Guides safe cystic duct division (see Q121)
• T-tube now rarely placed since laparoscopic CBD exploration with primary closure or biliary stenting preferred
• Post-operative ERCP: For residual stones without need for T-tube

• Open CBD exploration in complex cases
• CBD injury repair (temporary stenting)
• Impacted stones not cleared at surgery
• Severe inflammation precluding primary closure

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Q134 - Use of Nuclear Medicine in Surgery

DEFINITION

KEY PRINCIPLE

• Shows HOW tissues are working (metabolism, perfusion, receptor density)
• Detects physiological changes before anatomical changes visible

RADIOPHARMACEUTICALS USED IN SURGERY

• Half-life: 6 hours; gamma emitter 140 keV
• Labelled to various carriers for different targets:

• Tc-99m sulphur colloid injected peritumorally/subdermally 2-18h pre-op
• Gamma probe (handheld) intraoperatively guides surgeon to "hot" sentinel node(s)
• Combined with blue dye (Patent Blue V or ICG)
• Sentinel node removed → histological examination (frozen section or step-serial + IHC)
• If negative: Axillary clearance avoided (breast) or formal lymphadenectomy avoided (melanoma)
• Reduces morbidity of unnecessary complete lymph node dissection

• For neuroendocrine tumours (carcinoid, gastrinoma, glucagonoma, VIPoma)
• Somatostatin receptor scintigraphy: 111In-octreotide SPECT or 68Ga-DOTATATE PET
• Detects primary tumour + all metastases simultaneously
• Guides surgery (curative resection or debulking)

• Hepatobiliary scintigraphy
• Diagnoses: Acute cholecystitis (cystic duct obstruction = gallbladder not visualised at 4h), biliary leak, biliary atresia (in neonates), afferent loop syndrome post-gastrectomy

• Ectopic gastric mucosa in Meckel's diverticulum uptakes pertechnetate (like gastric mucosa)
• Confirms diagnosis non-invasively
• Sensitivity 85-90% in children; lower in adults

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Q135 + Q136 - PET Scan, Combination of PET + CT and MRI; Role of FDG-PET CT in GI Surgery (2008)

PET SCAN - PRINCIPLE

• PET = Positron Emission Tomography
• Radiotracer emits positron → annihilation with electron → two 511 keV gamma rays emitted 180° apart → detected by coincidence detectors → 3D reconstruction
• FDG (18F-Fluorodeoxyglucose): Most widely used tracer; glucose analogue; taken up by metabolically active cells (cancer, infection, inflammation) → trapped intracellularly (phosphorylated but not metabolised)
• SUV (Standardised Uptake Value): Quantifies tracer uptake; SUVmax >2.5 = suspicious for malignancy

PET-CT (Integrated)

• Simultaneously acquired PET + CT on same scanner
• PET: Functional/metabolic data (WHERE is metabolically active)
• CT: Anatomical localisation (WHAT structure is metabolically active)
• Combined: Far superior to either alone; "metabolic anatomy"
• Currently standard practice (pure PET now rarely used alone)

PET-MRI (Emerging)

• Simultaneous PET + MRI acquisition
• PET: Metabolic activity
• MRI: Superior soft tissue contrast
• Advantages: No additional radiation (vs PET-CT); better for brain, pelvic, liver tumours
• Limitation: Technical complexity; cost; limited availability

ROLE OF FDG-PET CT IN GI SURGERY

• Staging: Detects occult distant metastases (lung, bone, distant nodes, peritoneum) not seen on CT
• Pre-hepatectomy assessment for liver metastases: Identifies extrahepatic disease that would preclude curative hepatectomy (changes management in 15-30% of patients)
• Recurrence detection: Rising CEA post-resection + normal CT → FDG-PET identifies recurrence site
• Response assessment: After chemotherapy (RECIST criteria on CT is delayed; metabolic response on PET is earlier)

• Staging (M1 disease - distant metastases, supraclavicular nodes)
• Response assessment after neoadjuvant chemotherapy
• FDG-PET cannot reliably stage N (regional nodes) - CT/EUS better

• Limited (HCC often FDG-negative due to similar metabolism to normal liver)
• 11C-acetate or 11C-choline: Better for well-differentiated HCC
• FDG-PET useful for poorly differentiated HCC

• Staging; detects nodal + distant disease
• Predicts resectability

• Distinguishes malignant mass from inflammatory (autoimmune pancreatitis - moderate uptake vs high uptake in cancer)
• Detects unsuspected distant metastases pre-resection

• 68Ga-DOTATATE PET-CT (somatostatin receptor PET) >> FDG-PET for well-differentiated NET
• FDG-PET better for poorly differentiated/high-grade NET (glucose-avid)

• Detects primary tumour in ~40% of cases with metastases of unknown primary

• False positive: Infection/inflammation, sarcoidosis, post-surgical changes, bowel activity
• False negative: Well-differentiated tumours (low metabolism), tumours <5 mm, hyperglycaemia (competitive inhibition)
• Radiation: ~7 mSv (similar to CT); avoid in pregnancy
• Cost; not universally available; requires 6-hour fasting; 60-90 min uptake period

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Q137 - Osteomyelitis (2009)

DEFINITION

CLASSIFICATION

• Acute (<2 weeks; haematogenous; children)
• Subacute (2 weeks - 3 months; Brodie's abscess)
• Chronic (>3 months; sequestrum + involucrum; adults)

• Haematogenous (most common in children): Bacteraemia seeds metaphysis of long bones
• Direct inoculation (traumatic, surgical, open fracture)
• Contiguous spread (from adjacent soft tissue infection, diabetic foot)

• Type 1: Medullary (endosteal surface)
• Type 2: Superficial (outer cortex, contiguous infection)
• Type 3: Localised (full-thickness cortex but stable bone)
• Type 4: Diffuse (circumferential disease, mechanically unstable)

PATHOPHYSIOLOGY

1. Bacteraemia → seeding of metaphysis (sinusoidal vessels slow flow + microtrauma + lack of phagocytic lining)
2. Infection → inflammation → pus → ↑ intraosseous pressure → ischaemia
3. Pus penetrates cortex → subperiosteal abscess → elevates periosteum (rich blood supply) → cortex becomes avascular
4. Sequestrum: Dead avascular cortical bone
5. Involucrum: New bone laid down by elevated periosteum around sequestrum (bone-within-a-bone appearance)
6. Brodie's abscess: Chronic localised intraosseous abscess with surrounding sclerosis (high-resistance host)
7. Cloaca: Channel through cortex/involucrum through which pus/sequestrum discharges → sinus tract to skin

• Children: Staphylococcus aureus (most common, all ages)
• Neonates: Group B Streptococcus + S. aureus
• Sickle cell disease: Salmonella (also S. aureus)
• IV drug users: Pseudomonas, Candida
• Immunocompromised: Unusual organisms (fungi, atypical mycobacteria)
• Post-traumatic/surgical: S. aureus, S. epidermidis, Gram-negatives

CLINICAL FEATURES

• Fever, malaise, irritability (children)
• Localised bone tenderness, warmth, swelling at metaphysis
• Refusal to weight-bear; pseudo-paralysis in infants
• Joint movement usually preserved (unless septic arthritis coexists)

• Persistent or recurrent pain
• Discharging sinus(es)
• Deformity (growth disturbance in children)
• Pathological fracture (through weakened bone)

INVESTIGATIONS

• FBC: ↑ WBC, ↑ neutrophils
• ESR, CRP: Elevated; CRP more sensitive for early response to treatment
• Blood cultures: Positive in 50-60% acute haematogenous; obtain BEFORE antibiotics
• X-ray: Normal for first 7-10 days; then periosteal reaction; lytic areas; sequestrum/involucrum (chronic)
• MRI (best for early diagnosis): Signal change in medulla; periosteal reaction; soft tissue involvement; extent of disease; sensitivity 90-100%
• Tc-99m bone scan: 3-phase; sensitive early (before X-ray changes); hot on all 3 phases in osteomyelitis; differentiates from cellulitis (hot only on blood pool phase)
• CT: Sequestrum identification; cortical destruction; guide drainage
• Bone biopsy + culture: Definitive; percutaneous CT-guided or open; mandatory before antibiotics if possible (chronic osteomyelitis)

MANAGEMENT

1. Blood cultures → IV antibiotics immediately (do NOT delay for imaging beyond urgent X-ray)
2. IV antibiotics: Flucloxacillin + fusidic acid (MSSA); vancomycin/teicoplanin (MRSA); 4-6 weeks total (IV 2 weeks → oral 4 weeks)
3. Splinting: Immobilise limb; reduces pain; prevents pathological fracture
4. Surgical drainage: If abscess >2.5 cm (does not resolve on antibiotics), subperiosteal abscess, joint involvement, no improvement at 48h; drill-and-drain or arthrotomy

1. Pre-operative planning: CT + MRI; wound swab + bone biopsy for culture
2. Surgical sequestrectomy: Remove dead bone (sequestrum); curettage of granulation tissue
3. Saucerisation: Open all cavities (creates dead space → fill with vascularised tissue)
4. Dead space management:
   • Antibiotic-loaded bone cement beads (gentamicin cement)
   • Muscular/fascio-cutaneous flap coverage
   • Cancellous bone grafting (once infection controlled)
5. Prolonged antibiotics: 6-12 weeks based on organism sensitivity
6. Bone transport (Ilizarov): For segmental bone defects post-sequestrectomy

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Q138 - Vascular Problems of Supracondylar Fracture of Humerus (2009)

ANATOMY

• Supracondylar fracture = fracture of the distal humerus above the condyles
• Most common elbow fracture in children (age 5-10 years)
• Extension type (95%): Distal fragment displaced posteriorly
• Flexion type (5%): Distal fragment displaced anteriorly

VASCULAR ANATOMY AT RISK

• Brachial artery runs anterior to the elbow, closely applied to anterior distal humerus
• At fracture site, the sharp proximal fragment can:
  • Lacerate/contuse the brachial artery
  • Compress the brachial artery (spasm, kinking)
• Anterior interosseous nerve runs close (radial nerve, AIN most commonly injured)

VASCULAR COMPLICATIONS

• Cold, white, pulseless, painful hand with absent capillary refill
• Mechanism: Brachial artery trapped in fracture or kinking
• Management:
  • Immediate reduction + stabilisation (K-wires) under sedation/GA
  • After reduction: Check pulse return
  • If pulse does NOT return → Brachial artery exploration by vascular surgeon (within 6 hours)
  • Vessel repair: Primary repair, vein patch, interpositional vein graft
  • Late ischaemia → Volkmann's ischaemic contracture (irreversible if not treated)

• Hand pink and warm; oxygen saturations maintained; but pulse absent on palpation
• Mechanism: Brachial artery in spasm, kinked but not occluded; collateral circulation maintaining perfusion
• Management: More controversial (Bailey & Love):
  • Reduce + stabilise fracture (K-wires)
  • Observe closely (pulse often returns within 24-48h)
  • If signs of deterioration or compartment syndrome → explore artery urgently
  • Do not take a passive approach if concern re compartment syndrome

• Missed forearm compartment syndrome → muscle ischaemia → fibrosis → contracture
• Ischaemia → infarction of flexor muscles of forearm (flexor digitorum profundus + flexor pollicis longus most vulnerable)
• Presents: Wrist flexed, fingers and thumb flexed (intrinsic-minus hand)
• Severity: Mild (infarct of part of FDP) → Severe (whole flexor compartment)
• Prevention: Never immobilise in extreme elbow flexion; urgent treatment if pulseless
• Treatment (Late): Muscle slide (proximal release), muscle/tendon lengthening, neurectomy, free muscle transfer

NEUROLOGICAL COMPLICATIONS

• Anterior interosseous nerve (AIN): Most commonly injured; branch of median nerve; motor to FPL + FDP (index) + pronator quadratus; cannot make OK sign (pinch weakness)
• Radial nerve: Sensory dorsum of hand
• Median nerve: Full injury - rare
• Usually neuropraxia → recovery at 3-4 months
• If no recovery by 3 months → nerve exploration

LATE COMPLICATIONS

• Cubitus varus (Gunstock deformity): Malunion in varus; cosmetically disfiguring; functional impairment
  • Treatment: Lateral closing wedge osteotomy (dome/French osteotomy)
• Cubitus valgus: Less common; late ulnar nerve palsy (cubitus valgus → stretching of ulnar nerve)
• Myositis ossificans (heterotopic ossification) - usually from aggressive passive manipulation
• Stiffness (usually temporary in children)

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Q139 - Cervical Ribs and Its Effects (2010)

DEFINITION

ANATOMY

• C7 vertebra has enlarged transverse process or fully formed extra rib
• Types: Complete (articulates with 1st rib or sternum); Incomplete (ends in fibrous band - more symptomatic than complete bony rib); fibrous band alone
• Thoracic Outlet: Between anterior scalene + posterior scalene + 1st rib; key structures pass through

PATHOPHYSIOLOGY

• Cervical rib elevates and narrows the thoracic outlet space
• Compresses or distorts the subclavian artery + brachial plexus (lower trunk most often: C8, T1)
• Mechanism of arterial complications: Cervical rib → post-stenotic dilatation (aneurysm) of subclavian artery → turbulent flow → platelet deposition → thrombus → embolism to digits/hand

CLINICAL EFFECTS

• Lower trunk brachial plexus compression (C8, T1):
  • Pain and paraesthesia: Medial arm → forearm → 4th and 5th fingers (ulnar distribution)
  • Weakness and wasting: Intrinsic hand muscles (thenar + hypothenar - T1); weakness of grip
  • Gilliatt-Sumner hand: Wasting of thenar + hypothenar + interossei; almost pathognomonic of thoracic outlet syndrome
  • Symptoms worse on arm elevation, carrying heavy objects

• Subclavian artery stenosis/compression: Arm claudication, finger pallor on exercise
• Post-stenotic aneurysm of subclavian artery → Thromboembolism:
  • Digital ischaemia (finger tip gangrene, ulcers)
  • Raynaud's phenomenon (usually secondary - asymmetric = suspicious)
  • Acute limb ischaemia (embolism)
• Adson's test: Diminution/obliteration of radial pulse on deep inspiration + rotation of head to ipsilateral side + extension of neck (compresses subclavian by scalene); unreliable test

• Subclavian vein compression → effort thrombosis (young athletes - swimmers, throwers)
• Arm swelling + cyanosis + distended veins after exertion
• Treatment: Thrombolysis + anticoagulation + first rib resection

INVESTIGATIONS

• CXR: Cervical rib visible; elongated C7 transverse process
• Nerve conduction studies: Reduced ulnar nerve sensory action potential; reduced median nerve CMAP (T1)
• MRI cervical spine: Exclude disc disease, cord compression
• Duplex USS subclavian artery: Stenosis, aneurysm, dynamic compression with arm position
• CT angiography / MR angiography: Gold standard for vascular anatomy; aneurysm, stenosis, collaterals
• Arteriography: If surgical embolectomy/vascular reconstruction planned

MANAGEMENT

• Conservative first: Physiotherapy (scalene stretching, posture correction, strengthen shoulder girdle); avoid aggravating positions; 6-12 months
• Surgery (if conservative fails): Anterior scalenectomy (transaxillary or supraclavicular approach) ± first rib resection ± cervical rib excision
• Supraclavicular approach: Best exposure; allows brachial plexus neurolysis

• Thrombolysis if acute arterial occlusion (within 6 hours)
• Cervical rib resection + first rib resection (removes causative bony structure)
• Subclavian artery aneurysm: Repair/replacement with vein graft (supraclavicular + infraclavicular approaches)
• Embolectomy (Fogarty catheter) for peripheral thrombus

• Catheter-directed thrombolysis → anticoagulation 3-6 months → first rib resection (within 3 months)

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Q140 - Compartment Syndrome (2016)

DEFINITION

PATHOPHYSIOLOGY

• Increase in compartment contents (oedema, haemorrhage, external compression) → ↑ intra-compartmental pressure (ICP) → ↓ arteriovenous pressure gradient → ↓ capillary perfusion pressure → ischaemia
• Threshold: ICP >30 mmHg absolute, OR diastolic pressure - ICP ≤30 mmHg ("delta pressure")
• Ischaemia time → irreversible muscle necrosis at 6 hours; nerve ischaemia at 4-6 hours

CAUSES

• Fractures (most common - 70%): Tibia shaft, distal radius, supracondylar humerus
• Soft tissue injury (23%): Crush injury, contusion
• Burns (circumferential full-thickness)
• Tight casts/dressings
• Post-ischaemic reperfusion (revascularisation surgery)
• Bleeding disorders / anticoagulation
• Intravenous extravasation
• Prolonged compression (drug overdose, military anti-shock trousers)
• Abdominal: Massive fluid resuscitation, post-repair aortic aneurysm

CLINICAL FEATURES - THE 6 P's (Early to Late)

DIAGNOSIS

• Primarily clinical (do not delay treatment to measure pressure if clinical diagnosis clear)
• Intra-compartmental Pressure Monitoring:
  • Indications: Unconscious patient, regional anaesthesia masking pain, uncooperative patient, equivocal clinical signs
  • Method: Needle manometer (Stryker device); measure multiple compartments
  • Threshold for fasciotomy: Absolute pressure ≥30 mmHg OR Δp (DBP - ICP) ≤30 mmHg

MANAGEMENT

1. Remove all constricting dressings, casts, plasters - bivalve cast and spread fully
2. Elevate limb to heart level (NOT above - reduces arterial inflow further)
3. Correct hypotension (maintain perfusion pressure)
4. Senior input immediately
5. Prepare for emergency fasciotomy

• Performed under GA
• Incise skin + deep fascia with long longitudinal incisions
• All compartments of the affected region must be released

FASCIOTOMY INCISIONS - THIGH AND LEG (Q141 content)

COMPLICATIONS OF UNTREATED/LATE COMPARTMENT SYNDROME

• Volkmann's ischaemic contracture (forearm/hand)
• Foot drop (anterior compartment → tibialis anterior)
• Claw toes (posterior compartment → intrinsic foot muscles)
• Myonecrosis → Rhabdomyolysis → Myoglobinuria → Acute Kidney Injury (aggressive fluid resuscitation to maintain UO 1 ml/kg/h to prevent AKI)
• Infection (wet gangrene)
• Amputation
• Death (sepsis, multi-organ failure)

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Q141 - Anatomy of Different Compartments of Thigh and Leg; Describe Incisions to Decompress Compartments (2025)

COMPARTMENTS OF THE THIGH

• Less common than leg; usually from femoral shaft fracture or massive soft tissue injury
• FASCIOTOMY: Single lateral incision (mid-lateral thigh, from greater trochanter to lateral femoral condyle):
  • Opens anterior compartment (incise fascia lata anteriorly)
  • Opens posterior compartment (incise fascia lata posteriorly)
  • Medial compartment rarely requires decompression (separate medial incision if needed)

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COMPARTMENTS OF THE LEG (Lower Leg / Crus)

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FOUR-COMPARTMENT FASCIOTOMY OF LEG (Standard Technique - Bailey & Love)

• Longitudinal incision, 2 cm anterior to the fibula (anterior border of fibula)
• Length: Entire length of fibula (from fibular head to lateral malleolus)
• Identifies and incises anterior compartment fascia (anteriorly) and lateral compartment fascia (posteriorly)
• Beware: Superficial peroneal nerve exits lateral compartment at junction of middle and distal thirds (look for it)

• Longitudinal incision, 2 cm posterior to the medial border of the tibia
• Length: Mid-leg to just above medial malleolus
• Fascia incised to open superficial posterior compartment
• Retract gastrocnemius/soleus posteriorly → incise deep fascia over deep posterior compartment
• Beware: Saphenous nerve and great saphenous vein run along medial leg (just anterior to incision)

• Both skin AND deep fascia must be incised (not just skin)
• Check each compartment by inserting finger → confirm muscle belly visible and not tight
• If muscle colour poor (grey/black) → already necrotic → inform surgeon; debridement may be needed
• Wounds left open (too swollen to close)
• Delayed primary closure: At 48-72h once swelling subsides + muscle viable
• If cannot close: Split-skin graft

POST-FASCIOTOMY MANAGEMENT

• Wound dressings: VAC therapy to accelerate wound closure
• Elevation of limb at heart level
• Monitor urine output (myoglobinuria → AKI): Target UO >1 ml/kg/h
• IV fluid loading (crystalloid)
• Creatine kinase (CK) levels: Monitor for rhabdomyolysis
• Return to theatre at 48-72h: Wound inspection, further debridement if needed, delayed closure

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