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COMPREHENSIVE SURGICAL EXAM ANSWERS

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SECTION 1: ONCOLOGY

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a) Principles Underlying Non-Surgical Treatment of Cancer

• Based on the 5 Rs: Repair (sublethal damage), Redistribution (cell cycle), Repopulation (tumour regrowth), Reoxygenation (hypoxic cells), Radiosensitivity
• Uses ionizing radiation to cause DNA double-strand breaks, leading to cell death
• Tumour cells with poor DNA repair die preferentially
• Fractionation (small daily doses) spares normal tissue while maximizing tumour kill
• External beam, brachytherapy, stereotactic (SBRT/SRS)

• Cell-cycle specific agents (e.g., antimetabolites) vs. cell-cycle non-specific (e.g., alkylating agents)
• Log-kill hypothesis: each cycle kills a fixed fraction of cells; hence multiple cycles needed
• Combination regimens exploit different mechanisms to prevent resistance and maximize cell kill
• Drug resistance (intrinsic vs. acquired) limits efficacy
• Norton-Simon model: dose density matters; dose-dense regimens improve outcomes

• Used in hormone receptor-positive cancers (breast, prostate, endometrium)
• Reduces mitogenic drive by blocking receptor (tamoxifen), reducing hormone production (aromatase inhibitors, LHRH analogues), or castration
• Cytostatic rather than cytotoxic

• Harnesses host immune system: checkpoint inhibitors (PD-1/PD-L1, CTLA-4), cancer vaccines, adoptive T-cell therapy
• Most effective in immunogenic tumours (high mutational burden)

• Drugs directed against specific molecular targets (oncoproteins, growth factor receptors)

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a) Cancer Cachexia

• Weight loss >5% in 6 months, OR
• BMI <20 + weight loss >2%, OR
• Appendicular skeletal muscle index + weight loss >2%

• Tumour-produced factors: TNF-alpha (cachectin), IL-1, IL-6, IFN-gamma, PIF (proteolysis-inducing factor), LMF (lipid mobilizing factor)
• Systemic inflammation (elevated CRP)
• Increased REE (resting energy expenditure)
• Protein catabolism: ubiquitin-proteasome pathway activation in muscle
• Fat lipolysis: hormone-sensitive lipase activation
• Anorexia: elevated leptin, reduced ghrelin
• Insulin resistance, hypogonadism, anemia

• Anorexia, early satiety, fatigue, weakness
• Loss of skeletal muscle (sarcopenia) > fat loss
• Edema, anemia, psychological distress
• Impaired response to chemotherapy, reduced surgical tolerance

1. Nutritional support: High-protein diet, omega-3 fatty acids (EPA), oral nutritional supplements
2. Appetite stimulants: Megestrol acetate, corticosteroids (short-term), dronabinol
3. Anti-inflammatory agents: NSAIDs, thalidomide, EPA/DHA
4. Anabolic agents: Testosterone, selective androgen receptor modulators (SARMs), growth hormone
5. Anti-proteolytic agents: Bortezomib (in trials)
6. Exercise: Resistance training preserves muscle mass
7. Treat underlying tumour: Most effective strategy

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b) Oncoplastic Breast Surgery - Techniques, Indications, Complications, Current Status

Techniques (4 marks)

• Lateral transposition / round block (periareolar) technique
• Batwing mastopexy - central/upper tumours
• Racquet technique - for lateral tumours
• Tennis racquet pattern
• Local tissue advancement flaps

• Inferior pedicle reduction mammoplasty (Wise pattern) - large/lower pole tumours
• Superior/medial pedicle techniques
• Vertical scar (SPAIR technique)
• Therapeutic mammoplasty - combines reduction with excision

• Latissimus dorsi mini-flap (extended LD flap) - for lateral/upper outer quadrant
• Thoracodorsal artery perforator (TDAP) flap
• Lateral intercostal artery perforator (LICAP) flap
• TRAM/DIEP for larger defects

Indications (2 marks)

• Tumour-to-breast ratio unfavorable for standard wide local excision
• Central/periareolar tumours
• Large, ptotic breasts (reduction mammoplasty achieves oncology + aesthetics)
• Multicentric tumours where BCS planned
• Patient preference for BCS over mastectomy
• T2/T3 tumours responding to neoadjuvant chemotherapy
• Relative: BRCA carriers wishing BCS (with caution)

Complications (2 marks)

• Haematoma, seroma
• Wound dehiscence
• Infection
• Nipple-areola complex (NAC) necrosis (if pedicle compromised)
• Positive margins (re-excision needed in ~10%)

• Fat necrosis (can mimic recurrence on imaging)
• Asymmetry, contour deformity
• Changes in nipple sensation
• Contralateral symmetrisation procedure needed in ~30%
• Radiation effects on reconstructed breast (fibrosis, volume loss)
• Delayed detection of local recurrence

Current Status (2 marks)

• Now standard of care in specialist breast units globally
• Oncological safety equivalent to standard BCS (similar local recurrence rates ~1-3% at 5 years)
• NICE guidelines and EUSOMA recommend offering oncoplasty
• Requires multidisciplinary team: breast surgeon trained in oncoplasty + plastic surgeon
• Contralateral symmetrisation can be performed simultaneously or staged
• Increasing use of pre-operative planning with 3D imaging (Vectra, Breast Sculptor)
• Challenges: lack of standardized training, technical variability, longer operative time

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b) Targeted Therapy in Cancer Treatment

• Tyrosine Kinase Inhibitors (TKIs):
  • Imatinib (BCR-ABL in CML, c-KIT in GIST)
  • Erlotinib/Gefitinib (EGFR in NSCLC)
  • Lapatinib (HER2 in breast cancer)
  • Vemurafenib (BRAF V600E in melanoma)
• mTOR inhibitors: Everolimus (renal cell carcinoma, breast)
• CDK 4/6 inhibitors: Palbociclib, ribociclib, abemaciclib (HR+ breast cancer)
• PARP inhibitors: Olaparib, rucaparib (BRCA-mutated breast/ovarian)
• VEGFR inhibitors: Sunitinib, sorafenib (RCC, HCC)

• Anti-HER2: Trastuzumab (Herceptin), pertuzumab - HER2+ breast/gastric
• Anti-EGFR: Cetuximab, panitumumab - colorectal (KRAS wild-type), HNSCC
• Anti-VEGF: Bevacizumab - colorectal, lung, glioblastoma
• Anti-CD20: Rituximab - NHL, CLL
• Anti-CD38: Daratumumab - multiple myeloma
• ADCs (Antibody-Drug Conjugates): Trastuzumab emtansine (T-DM1), trastuzumab deruxtecan

• Require biomarker testing before use (predictive biomarkers)
• Tumours must express the target (e.g., HER2 amplification, EGFR mutation)
• Resistance develops (secondary mutations, alternative pathway activation)
• Often combined with conventional chemotherapy/hormonal therapy
• Companion diagnostics are mandatory (e.g., FISH for HER2, PCR for EGFR mutation)

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a) Environmental Causes of Cancer

• Smoke contains >70 carcinogens (PAHs, nitrosamines, benzene)
• Lung, oropharynx, larynx, esophagus, bladder, kidney, cervix, pancreas
• Smokeless tobacco: oral cavity cancers

• High animal fat, red/processed meat: colorectal, prostate cancer
• Aflatoxins (fungal toxin in stored grains): hepatocellular carcinoma
• Alcohol: oral, pharyngeal, esophageal, hepatic, breast cancer
• Obesity: endometrial, breast (postmenopausal), colorectal, esophageal adenocarcinoma

• H. pylori: gastric cancer
• HPV (16, 18): cervical, anal, oropharyngeal cancers
• HBV/HCV: hepatocellular carcinoma
• EBV: Burkitt's lymphoma, nasopharyngeal carcinoma, Hodgkin lymphoma
• HIV: Kaposi's sarcoma, NHL
• HTLV-1: adult T-cell leukemia/lymphoma

• Ionizing: UV (skin cancers - BCC, SCC, melanoma), X-rays/gamma rays (leukemia, thyroid), radon (lung)
• Non-ionizing: UV is major risk for skin cancers

• Asbestos: mesothelioma, lung cancer
• Benzene: AML, NHL
• Vinyl chloride: hepatic angiosarcoma
• Aniline dyes: bladder cancer
• Aromatic amines: bladder cancer
• Coal tar/pitch: skin cancers
• Arsenic: lung, skin, bladder

• Exogenous estrogen (HRT): breast, endometrial cancer
• Early menarche, late menopause, nulliparity: breast cancer risk
• OCP: modest increase in breast/cervical cancer

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a) Intra-Operative Tissue (Pathological) Diagnosis - Techniques

• Technique: Fresh tissue transported immediately to pathology lab. Tissue frozen in cryostat at -20°C, cut at 5-7 microns, stained with H&E, read in 15-20 minutes
• Uses:
  • Confirm malignancy before radical resection
  • Assess surgical margins (margin status)
  • Assess lymph nodes (sentinel node biopsy)
  • Identify tissue type (especially for thyroid, parathyroid)
  • Confirm adequacy of biopsy
• Accuracy: ~97-98% for malignancy; limited for small lesions, fatty tissue, lymphoma, calcified tissue
• Limitations: Ice crystal artefact, freezing distorts tissue architecture, small specimens may be consumed

• Technique: Cut surface of fresh tissue touched/pressed onto glass slide, fixed and stained (H&E or Papanicolaou)
• Faster than frozen section (5-10 min)
• Better for haematological tissue (lymph nodes)
• Particularly useful for sentinel lymph node assessment in breast cancer (OSNA - One-Step Nucleic Acid Amplification is a molecular method)
• Limitations: Cannot assess architecture, experience-dependent

• Tissue scraped and smear made on glass slide
• Used for brain tumours, soft tissue lesions

• Molecular technique for SLN in breast cancer
• Detects CK19 mRNA (cytokeratin 19)
• Whole lymph node homogenized and analyzed
• Results in 30-40 minutes
• Advantages: avoids sampling error, quantitative, higher sensitivity than frozen section
• Disadvantage: destroys tissue, cannot be used for conventional histology

• Assessment of margins by surgeon + pathologist
• Ink margins (multiple colors for orientation)
• Important for breast conservation and colorectal surgery

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a) Multi-Disciplinary Team (MDT) in Oncology

• Core members: Surgical oncologist, medical oncologist, radiation oncologist, radiologist (with oncology expertise), pathologist, specialist nurse/cancer nurse coordinator
• Extended members: Palliative care physician, physiotherapist, dietitian, psychologist/counselor, social worker, pharmacist, geneticist (for BRCA/Lynch syndrome etc.), reconstructive surgeon

• Weekly/fortnightly meetings
• Patient cases presented by team member
• Radiology reviewed (CT, MRI, PET scans)
• Pathology reviewed
• Discussion of TNM stage, performance status, comorbidities, patient preferences
• Consensus treatment recommendation documented
• Key worker (usually clinical nurse specialist) communicates plan to patient

1. Clinical: Reduces errors, improves staging accuracy, evidence-based treatment, avoids over/under-treatment, specialized expertise for complex cases
2. Patient outcomes: Improved survival, reduced mortality (multiple studies)
3. Communication: Better inter-specialty coordination
4. Education: Training of junior staff, audit opportunities
5. Research: Facilitates clinical trial enrollment
6. Efficiency: Avoids fragmented care, reduces delays

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b) Criteria and Advantages for Screening of Cancer

1. The condition should be an important health problem
2. There should be an accepted treatment for recognized disease
3. Facilities for diagnosis and treatment should be available
4. There should be a recognizable latent or early symptomatic stage
5. There should be a suitable test or examination
6. The test should be acceptable to the population
7. The natural history of the condition should be adequately understood
8. There should be an agreed policy on whom to treat as patients
9. The cost should be economically balanced in relation to possible expenditure on medical care as a whole
10. Case-finding should be a continuing process

• High sensitivity (minimize false negatives - miss no true cases)
• High specificity (minimize false positives - avoid unnecessary anxiety/investigation)
• Simple, safe, non-invasive, acceptable
• Affordable, reproducible, reliable
• Lead time adequate to allow intervention

1. Detects cancer at earlier, more treatable stage
2. Reduces cancer mortality (proven for breast, colorectal, cervical, lung in high-risk)
3. Less morbid treatment needed for early-stage disease
4. May detect precancerous lesions (e.g., adenomas in colonoscopy)
5. Provides reassurance to those who screen negative
6. Population-level data for epidemiological research

• Lead time bias (apparent survival improvement without real benefit)
• Length bias (screening preferentially detects slow-growing tumours)
• Overdiagnosis (detecting cancers that would never become clinically significant)
• False positives cause anxiety, unnecessary investigations, cost
• Radiation exposure (mammography, CT)
• False security in true negatives

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a) Pathological Changes in Malignant Transformation

1. Oncogene activation: Proto-oncogenes mutated/amplified to oncogenes (RAS, MYC, HER2, EGFR) - gain of function mutations
2. Tumour suppressor gene inactivation: TP53, RB1, APC, BRCA1/2 - loss of function (two-hit hypothesis for RB)
3. DNA repair gene mutations: MLH1, MSH2 (mismatch repair) - microsatellite instability
4. Telomerase reactivation: Immortalization, avoidance of cellular senescence
5. Epigenetic changes: Methylation of promoter regions, histone modification

• Loss of differentiation (dedifferentiation/anaplasia)
• Increased nuclear:cytoplasmic ratio
• Nuclear pleomorphism, hyperchromasia
• Prominent nucleoli
• Increased/abnormal mitoses
• Loss of normal architecture
• Loss of cell polarity

1. Sustained proliferative signaling: Self-sufficient growth signals
2. Evading growth suppressors: Insensitivity to anti-growth signals
3. Resisting cell death: Anti-apoptotic (BCL2 overexpression)
4. Enabling replicative immortality: Telomerase
5. Inducing angiogenesis: VEGF upregulation (Folkman)
6. Activating invasion & metastasis: Loss of E-cadherin, MMP upregulation, EMT (epithelial-mesenchymal transition)
7. Reprogramming energy metabolism: Warburg effect (aerobic glycolysis)
8. Evading immune destruction: PD-L1 expression, regulatory T-cells

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Viral Carcinogens and Associated Tumours

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Screening Methods for Early Detection

• Mammography: Mainstay; 2-view digital mammography
  • Age 40-74: Annual (ACR/ACS) or biennial (USPSTF)
  • India (IARC): Biennial mammography 50-69 years
  • Sensitivity ~75-85%, specificity ~90%
• Clinical Breast Examination (CBE): Annual (ACS)
• Breast Self-Examination (BSE): Monthly from age 20 (awareness)
• Ultrasonography: Adjunct for dense breasts, not primary screening tool
• MRI: High-risk women (BRCA mutation, lifetime risk >20%): annual MRI + mammography from age 25-30
• Tomosynthesis (3D mammography): Improved detection, reduced recall rates

• Start at age 45 (ACS 2018) / 50 (USPSTF)
• Colonoscopy: Every 10 years - gold standard, allows biopsy and polypectomy
• CT Colonography (virtual colonoscopy): Every 5 years
• Flexible sigmoidoscopy: Every 5 years (detects only left colon)
• Stool-based tests:
  • FIT (Fecal Immunochemical Test): Annual - preferred non-invasive
  • Guaiac-based FOBT (gFOBT): Annual
  • Multi-target stool DNA test (Cologuard): Every 1-3 years
• Positive non-invasive test → colonoscopy

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a) Clinical Implications of Gompertzian Growth in Oncology

• Tumour growth is not linear; it follows a sigmoid (S-shaped) curve
• Initial exponential growth → progressively decelerating growth rate → plateau
• Rate of growth decreases as tumour enlarges (due to vascular limitation, nutrient deficiency, accumulation of necrotic cells, increasing cell cycle time)
• Mathematical: dN/dt = α·N·ln(K/N) where K = carrying capacity

1. Small tumours grow fastest (highest growth fraction): This is when chemotherapy is most effective (Norton-Simon model). Most clinically detectable tumours have already passed their most rapid growth phase.
2. Skipper-Schabel log-kill model: A fixed fraction (not fixed number) of cells is killed with each treatment cycle. Combined with Gompertzian kinetics, this means earlier treatment gives better results.
3. Dose density: Administering chemotherapy more frequently (dose-dense) exploits the rapid regrowth between cycles, which is faster when tumours are small (lower on the growth curve). Basis for dose-dense AC-T in breast cancer.
4. Metastatic tumours regrow faster: After resection, micrometastases are on the steeply rising part of the growth curve - hence adjuvant chemotherapy should start promptly.
5. Neoadjuvant chemotherapy: Downstaging exploits initial rapid kill when tumour burden is high enough to be on the decelerating phase.
6. Surgical timing: Removing primary tumour may remove "growth suppressor" effect on metastases (angiostatin/endostatin from primary) → accelerated metastatic growth post-surgery (Folkman hypothesis).
7. Tumour dormancy: Some tumours reach equilibrium (plateau) and remain dormant for years; explains late recurrences.
8. Treatment resistance: Tumours in growth plateau have fewer dividing cells → less sensitive to cell-cycle-specific drugs.

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b) Lead Time and Length Bias in Breast Cancer Screening

• Definition: The artificial lengthening of apparent survival time due to earlier detection by screening, without any actual prolongation of life.
• Mechanism: If a tumour is detected by screening at time T1 and would have presented symptomatically at T2, the lead time = T2 - T1. If the patient dies at the same time T3 regardless of when detected, measured survival from T1 is longer than from T2, but actual survival (T3-T1 vs T3-T2) is unchanged.
• Example: Screening detects breast cancer 2 years earlier. Apparent 5-year survival improves from 60% to 90% - but the patient dies at the same time. The gain is illusory.
• Solution: Use mortality rate (deaths per 100,000 population/year) rather than survival rate as the endpoint in screening trials. RCTs (Swedish Two-County Trial, NBSS) compare disease-specific mortality, not survival.

• Definition: Screening preferentially detects slow-growing, less aggressive tumours because they have a longer detectable preclinical phase (soiurn time), while rapidly growing cancers progress to symptoms before the next screening round.
• Mechanism: Probability of detection is proportional to the length of the preclinical phase. Slow-growing tumours = longer preclinical phase = more likely to be screen-detected.
• Implication: Screen-detected cancers appear to have better prognosis (because they are inherently less aggressive), not necessarily because of screening benefit.
• Extreme form - Overdiagnosis: Detecting tumours so indolent they would never cause clinical symptoms or death (DCIS debate in breast cancer - estimated overdiagnosis rate 20-50% in some studies).
• Solution: Compare biologically matched groups; population-based mortality statistics over long periods.

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a) HIPEC - What is it? b) Indications c) Complications

a) What is Hyperthermic Intraperitoneal Chemotherapy (HIPEC)?

• Peritoneal-plasma barrier: The peritoneum limits systemic absorption, allowing high local drug concentrations (10-1000x higher than plasma) with limited systemic toxicity
• Hyperthermia (41-43°C):
  • Enhances drug penetration into tissue
  • Direct cytotoxicity (protein denaturation)
  • Inhibits DNA repair mechanisms
  • Enhances chemotherapy efficacy (especially for platinum compounds and mitomycin C)
  • Selective toxicity to poorly vascularized (hypoxic) tumour cells
• Timing: Immediately after CRS because: residual microscopic disease is treated, blood supply to adhesions is restored, drug penetration is optimal

• CRS achieves complete or near-complete macroscopic clearance (CC-0, CC-1)
• Peritoneal Carcinomatosis Index (PCI) scored 0-39
• Heated perfusate (IPHP circuits - Performer, Performer HT) at 41-43°C
• Duration: 30-120 minutes depending on drug/protocol
• Drugs: Mitomycin C (most common), cisplatin, oxaliplatin, doxorubicin
• Closed vs. open (coliseum) technique

b) Indications for HIPEC

1. Pseudomyxoma peritonei (PMP) - from appendiceal mucinous tumours: most favorable outcomes (10-year OS ~63%)
2. Peritoneal mesothelioma - malignant peritoneal mesothelioma: 5-year OS ~47% (vs. <1 year for systemic therapy)
3. Colorectal cancer with peritoneal metastases (selected patients, PCI <20): Phase III PRODIGE 7 trial controversially showed no survival benefit with oxaliplatin HIPEC over CRS alone; ongoing debate
4. Ovarian cancer with peritoneal spread: van Driel et al. (NEJM 2018) - improved OS with interval debulking + HIPEC
5. Appendiceal adenocarcinoma with peritoneal spread

• Gastric cancer with peritoneal metastases (GASTRICHIP trial)
• Hepatocellular carcinoma
• Prophylactic HIPEC in high-risk colorectal cancer at initial resection (COLOPEC trial - not supported by evidence)
• Peritoneal sarcomatosis (selected cases)

• High PCI (>20 for CRC, >39 generally)
• Distant metastases (liver, lung) - relative
• Poor performance status (ECOG >2)
• Unresectable disease
• Severe comorbidities (cardiac, renal, hepatic)

c) Complications of HIPEC

• Bowel anastomotic leak (5-15%)
• Bowel perforation
• Abdominal abscess/intra-abdominal sepsis
• Prolonged ileus
• Haemorrhage
• Wound complications (infection, dehiscence, hernia)
• Fistulae (entero-cutaneous, pancreatic)
• Injury to adjacent structures (ureter, bladder, spleen)

• Haematological toxicity: Myelosuppression (especially with mitomycin C) - neutropenia, thrombocytopenia
• Nephrotoxicity: Cisplatin can cause acute kidney injury (requires vigorous hydration, amifostine)
• Hepatotoxicity: Elevated transaminases
• Cardiotoxicity: Arrhythmias (related to temperature and volume shifts)
• Electrolyte disturbances: Hyponatremia (especially with oxaliplatin)
• Pulmonary complications: Pleural effusion, ARDS (fluid shifts)
• Peripheral neuropathy: Oxaliplatin-related

• Hypoalbuminemia/malnutrition (prolonged recovery)
• Ileus/bowel obstruction
• DVT/PE (extended surgery + immobility)
• ICU admission often required post-operatively

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SECTION 2: SURGICAL INSTRUMENTS & TECHNIQUES

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a) Surgical Blades and Knife Handles

• No. 3 handle: Fits blades 10, 11, 12, 15 - most common in general surgery
• No. 3L (long) handle: Same blades as No. 3 but longer; for deep cavity work (laparotomy, pelvic surgery)
• No. 4 handle: Fits blades 20, 21, 22, 23, 24 - for larger blades
• No. 4L (long): Large blade, extended reach
• No. 7 handle: Thin, pencil-shaped; fits blades 10, 11, 12, 15; for fine/delicate work (ophthalmic, plastic)
• No. 9 handle: For blades 22, 23 (ENT use)

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b) Types of Wound Dressings

• Simple absorbent pads (gauze): Primary wound contact, absorbs exudate; dry, may stick to wound
• Tulle gras (paraffin gauze): Non-adherent, allows exudate through; for clean/granulating wounds (Jelonet, Sofratulle)
• Dry dressings: For clean, healing wounds with minimal exudate
• Wet-to-dry: Debridement via adherence; now largely abandoned (causes pain, disrupts granulation)

• Hydrocolloids (DuoDERM, Comfeel): Gel-forming polymers, maintain moist environment, autolytic debridement; for shallow wounds, pressure ulcers
• Hydrogels (Intrasite gel, Aquaform): High water content, rehydrate necrotic tissue, autolytic debridement; for dry/necrotic wounds, painful wounds
• Alginates (Kaltostat, Sorbalgon): Derived from seaweed, highly absorbent, haemostatic, gel-forming; for highly exuding wounds, cavity wounds, venous ulcers
• Foams (Allevyn, Mepilex): Polyurethane foam, absorbent, thermal insulation, for moderate-highly exuding wounds
• Semipermeable films (Tegaderm, OpSite): Transparent, waterproof, moisture-vapor permeable; for superficial wounds, IV site protection, secondary dressings
• Hydrofibers (Aquacel): High absorbency, gel-forming; for heavily exuding wounds

• Silver dressings (Mepilex Ag, Acticoat): Broad-spectrum antimicrobial; infected/at-risk wounds, burns
• Iodine-based (Inadine, Iodosorb): Cadexomer iodine slowly releases iodine; infected wounds
• Honey dressings (Medihoney): Manuka honey, antimicrobial, anti-inflammatory, deodorizing; infected/malodorous wounds

• Negative Pressure Wound Therapy (NPWT/VAC therapy): Sub-atmospheric pressure (-125 mmHg), promotes granulation, removes exudate; for complex wounds, dehiscence, diabetic foot, open abdomen
• Biological dressings: Skin allografts (cadaveric), xenografts (pig skin), amnion - for burns, large wounds
• Collagen/matrix dressings: Tissue engineering, chronic wounds

• Maintain moist environment
• Allow gas exchange
• Thermally insulating
• Non-adherent, painless removal
• Prevent bacterial contamination
• Absorb excess exudate
• Conform to wound shape
• Cost-effective

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a) Classification of Suture Materials

• Monofilament: single strand, less infection risk, smooth passage, harder to handle, knots slip (nylon, prolene, PDS, Monocryl)
• Multifilament (braided): easier to handle, better knot security, more tissue drag, more infection risk (Vicryl, Dexon, silk)

• Natural: catgut, silk, linen, steel
• Synthetic: all others

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b) Surgical Staplers for Bowel Anastomosis

• TA stapler: Applies 1-2 staggered rows of staples across bowel without cutting. Used for closure of bowel ends (e.g., resection margin in LAR, Hartmann's)
• GIA stapler (linear cutter): Applies two double rows of staples AND cuts between them simultaneously. Creates side-to-side anastomosis; used in small bowel anastomosis, gastric bypass
• Available in various lengths: 30, 45, 60, 80 mm; various staple heights for different tissue thickness

• Used for end-to-end or end-to-side circular anastomosis
• Essential for low anterior resection (colorectal anastomosis)
• Sizes: 21, 25, 28, 29, 31, 33 mm diameter
• Fires two circular rows of staples and cuts a "donut" of tissue
• Inserted transanally or via enterotomy
• Purse-string sutures placed on both bowel ends before anvil placement

• Roticulating/articulating head for laparoscopic use
• Used in laparoscopic bowel resections, sleeve gastrectomy, Whipple's
• Reloadable cartridges

• After dividing bowel with linear cutter, antimesenteric corners are cut, GIA stapler fires side-to-side, enterotomies closed with another firing
• Results in wide-lumen, well-vascularized anastomosis
• Used routinely for small bowel, ileocolic anastomosis

• Purse string on proximal colon, anvil inserted and tied
• EEA stapler inserted transanally, spike advanced through rectal stump
• Anvil attached, stapler fired, 2 "donuts" checked for completeness
• Air leak test with saline

• Speed and reproducibility
• Accurate hemostasis
• Suitable for difficult locations (low rectum, esophagogastric junction)
• Reduced operator dependence
• Allows single-layer anastomosis with consistent results

• Cost
• Anastomotic leak/stricture (ring stricture with circular staplers)
• Technical failure (misfire, incomplete stapling)
• Not suitable for inflamed/edematous/very thick bowel

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a) Principles of Cutting and Coagulation Mode in Electrosurgery

• Waveform: Continuous, undamped (unmodulated) sinusoidal wave
• Effect: Very high power density at electrode tip → tissue temperature rapidly exceeds 100°C → intracellular water vaporizes explosively → cell disruption/vaporization → clean cut
• Appearance: Thin, clean incision with minimal lateral thermal spread
• Hemostasis: Poor (vessels simply cut)
• Use: Clean incisions when hemostasis is not primary concern, or with monopolar in blend mode

• Waveform: Interrupted, damped (modulated) wave with duty cycle ~6% (active only 6% of time)
• Effect: Lower average power → tissue heats more slowly → temperature 70-90°C → protein denaturation → cell shrinkage, collagen denaturation → tissue coagulation (eschar formation)
• Appearance: Brown/black charring, tissue desiccation
• Types:
  • Fulguration: Spray coagulation - electrode held away from tissue, sparks jump to tissue surface, widely used for oozing surfaces
  • Desiccation: Electrode in contact with tissue

• Intermediate waveform (duty cycle 50-80%)
• Combines cutting and coagulation
• Provides hemostatic cutting

• Current flows between two tines of the forceps only
• No return electrode plate needed
• Safer, more precise, less lateral spread
• Used near vital structures (brain, eye, ear, digits)
• Lower power required

• Monopolar: current from active electrode through patient to return electrode (dispersive pad) - higher power, risk of remote burns if dispersive pad poor contact
• Bipolar: current between two tips only - safer, precise

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b) Sutures and Devices for Small Bowel and Bilio-enteric Anastomosis

• Sutures: 3-0 or 4-0 absorbable (Vicryl/PDS) or non-absorbable (silk, polypropylene)
• Single-layer extra-mucosal (all coats): most popular, minimal luminal compromise
• Double-layer (inner all-coats continuous + outer Lembert seromuscular interrupted): traditional
• Devices: GIA linear stapler for side-to-side, EEA circular stapler for end-to-end

• Sutures: 4-0 or 5-0 PDS (monofilament, absorbable) - preferred for bile duct anastomosis
  • Monofilament reduces bile stone/sludge formation on suture
  • 4-0 Vicryl also used
  • Silk (historical) - avoided now (bile duct stone formation on intraluminal silk)
• Single-layer interrupted technique preferred (allows precise mucosal apposition, accommodates size discrepancy)
• Continuous posterior + interrupted anterior also used
• Stent: Trans-anastomotic stent (silastic tube) for difficult anastomoses
• Roux-en-Y limb ~60 cm to prevent bile reflux

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a) Advances in Topical Haemostatic Therapy

• Absorbable gelatin (Gelfoam, Spongostan): Absorbs blood, swells, tamponade effect; absorbed in 4-6 weeks
• Oxidized regenerated cellulose (Surgicel, Oxycel): Lowers local pH, denatures proteins, bactericidal; absorbed in 2-6 weeks; avoid near CNS/optic nerve
• Microfibrillar collagen (Avitene): Activates platelets (extrinsic pathway); absorbed in 3 months; avoid in contaminated wounds

• Thrombin (topical): Bovine (Thrombin-JMI), recombinant human (Recothrom), pooled human plasma (Evithrom); converts fibrinogen to fibrin; used alone or combined with gelatin matrix
• FloSeal Matrix: Gelatin granules + human thrombin; swells, tamponades, promotes clotting; excellent hemostasis in bleeding surfaces
• Surgicel SNoW: Oxidized regenerated cellulose in fibrillar form; for fine bleeding surfaces

• Tisseel (Baxter), Evicel, Artiss: Fibrinogen + thrombin + Factor XIII; when mixed, form stable fibrin clot in <60 seconds
• Mimics final pathway of coagulation
• Uses: Hepatic surgery, vascular, colorectal, plastic surgery
• Risk of viral transmission (human-derived), anaphylaxis (bovine aprotinin)

• Cyanoacrylate (Histoacryl, Dermabond): Tissue adhesive for skin wounds, vascular leaks
• Polyethylene glycol polymers (CoSeal): Vascular anastomoses
• Albumin/glutaraldehyde (BioGlue): Cardiac/aortic surgery

• Chitosan-based hemostats (HemCon, Celox, QuikClot-Z): Combat use, trauma; positively charged, attracts RBCs
• Kaolin-impregnated gauze (QuikClot Combat Gauze): Contact activation of clotting
• Synthetic peptide self-assembling nanofibers (PuraStat): Endoscopic haemostasis in GI bleeds
• Recombinant spider silk hemostats: Experimental
• TachoSil: Collagen fleece + thrombin + fibrinogen; compressed application to liver/spleen
• Arista AH (microporous polysaccharide hemispheres): Absorbs water from blood, concentrates clotting factors

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b) Types of Surgical Suture Needles

1. Cutting Needles:
   • Conventional cutting: Triangle cross-section, cutting edge on INNER (concave) curve - risk of cutting toward/through tissue
   • Reverse cutting: Cutting edge on OUTER (convex) curve - prevents cutting through tissue toward wound edge; stronger needle; most common for skin
   • Side-cutting (spatula): Flat on top and bottom, cutting edges on sides; designed for layered tissue - ophthalmic surgery
2. Tapered/Round-bodied Needles (no cutting edge):
   • Circular cross-section, sharp tip only
   • Pierce tissue by separating fibers, not cutting
   • Leaks less; for gut, peritoneum, soft tissue, blood vessels
   • Variants: tapercut (taper body with reverse cutting tip) - for tough tissues like fascia
3. Blunt Needles:
   • Rounded blunt tip
   • Cannot penetrate tissue; used for mass closure of abdominal fascia in contaminated fields
   • Reduces needlestick injury (safer for surgeons)

• Straight (Keith needle): Manual use (not in needle holder); suturing accessible surfaces, skin, tendon
• Half-curved (ski needle): Limited use
• 1/4 circle: Ophthalmic use
• 3/8 circle: Most common; skin, superficial tissues
• 1/2 circle: Deep cavities (GI, pelvic surgery) - most versatile
• 5/8 circle: Urological surgery, deep pelvic procedures

• Round body: Soft tissues
• Flattened body: Better grip in needle holder

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a) Desirable Characteristics of Suture Materials

1. Sterile: Bacteria-free, packaged in sterile conditions
2. Adequate tensile strength: Sufficient to hold wound edges together during healing
3. Predictable and consistent absorption/tensile loss: Reliable behavior in vivo
4. Minimal tissue reactivity: Low inflammatory reaction, no foreign body response
5. Non-carcinogenic, non-teratogenic: Biologically inert
6. Non-allergenic: No hypersensitivity
7. Infection resistance: Does not harbor bacteria; low capillarity
8. Knot security: Knot holds without slipping or fraying
9. Ease of handling: Pliable, does not have memory, easy to tie
10. Smooth passage through tissue: Minimal tissue drag
11. Available in variety of sizes: 11-0 to 5
12. Hemostatic: Some degree of hemostasis when ligated
13. Cost-effective: Affordable
14. Radiopaque (for certain applications): Detectability if retained

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b) Types of Wound Healing

• Clean wound, edges well-approximated (sutured, stapled, glued)
• Minimal tissue loss, minimal contamination
• Phases: Inflammation (0-3 days) → Proliferation/fibroplasia (3-21 days) → Maturation/remodeling (21 days - 2 years)
• Minimal scarring
• Example: Clean surgical incision

• Wound left open, large tissue defect, contaminated
• Granulation tissue fills defect from base upward
• Wound contraction by myofibroblasts (60-80% of closure)
• Epithelialization from wound margins
• Prolonged, results in more scar
• Example: Abscess cavity, pressure ulcer, dog bite wound

• Wound initially left open (contaminated/infected), then sutured after 4-5 days once infection controlled and granulation established
• Combines benefits of secondary (infection clearance) and primary (better cosmesis than full secondary healing)
• Example: Contaminated abdominal wound, traumatic wound

• Haemostasis (0-few hours): Platelet plug, fibrin clot, growth factor release (PDGF, TGF-β)
• Inflammation (0-3 days): Neutrophils → macrophages, debridement, cytokines
• Proliferation (3-21 days): Fibroplasia (fibroblasts lay collagen), angiogenesis (VEGF), epithelialization
• Remodeling (21 days - 2 years): Type III collagen replaced by Type I, wound contraction, scar maturation; maximum tensile strength 80% of normal skin at 3 months

• Local: Blood supply, infection, foreign body, tension, radiation
• Systemic: Nutrition (protein, Vit C, Vit A, Zinc), diabetes, steroids, immunosuppression, age, anemia, uremia

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a) LASER in Surgery - Basic Principles and Uses

• LASER = Light Amplification by Stimulated Emission of Radiation
• Stimulated emission: When a photon of appropriate energy encounters an excited atom, it stimulates emission of a second, identical photon (same phase, wavelength, direction) - coherent, monochromatic, collimated light
• Lasing medium determines wavelength: gas (CO2, Ar, He-Ne), solid-state (Nd:YAG, KTP), semiconductor (diode), liquid (dye)
• Pumping: External energy source (electrical, optical) raises electrons to excited state
• Optical cavity: Mirrors at both ends amplify light; partially reflective mirror allows laser beam exit

1. Photothermal: Heat generated; evaporation (cutting at >100°C), coagulation (60-100°C), protein denaturation (45-60°C)
2. Photomechanical: Rapid thermal expansion → shock waves → tissue disruption (Q-switched lasers, lithotripsy)
3. Photochemical: Photosensitizer activated by light → reactive oxygen species → cell death (photodynamic therapy)
4. Photoablation: UV lasers break molecular bonds directly (excimer - corneal surgery)

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b) Principles, Types and Precautions of Surgical Diathermy

• High-frequency AC current (300 kHz - 3 MHz) avoids nerve/muscle stimulation
• Heat generated = I² × R × t; current density determines heat
• Monopolar: active electrode (small, high current density) → patient → dispersive pad (large, low density, no burn)
• Bipolar: between two electrode tips only

1. Monopolar: Most common; uses active electrode + distant dispersive pad
2. Bipolar: Between two forceps tips; no pad needed; safer near CNS, eyes, extremities
3. Ultrasonic (Harmonic scalpel): Not true diathermy; vibrates at 55,500 Hz; cuts and coagulates simultaneously; minimal lateral thermal spread; smoke-free; ideal near nerves
4. LigaSure (vessel sealing): Bipolar current + pressure → permanent vessel seal up to 7 mm diameter
5. NOTES/laparoscopic hook/spatula: Monopolar instruments for laparoscopic use
6. Argon beam coagulator: Ionized argon gas conducts current; diffuse surface coagulation; for liver/spleen surface ooze

• Dispersive pad: large, good contact, away from implants/bony prominences, not over scar/hair
• Remove jewelry (rings can cause burns)
• Flammable prep solutions (alcohol) must be dry before diathermy use
• Avoid in explosive environment (ether, high O2)
• Pacemakers: bipolar preferred; magnet on pacemaker; cardiologist consultation; use minimum power
• Do not hold active electrode near implants (hip, knee prosthesis)
• Insulation failure in laparoscopic instruments: inspect before use
• Capacitative coupling in laparoscopy: use metal trocar + metal cannula; never place through plastic trocar
• Direct coupling: active electrode touching other metal instrument → burn at remote site
• Keep active electrode in insulated holder when not in use (accidental firing)
• Avoid use on appendages (penis, digits) - current concentration risk
• Fire risk: laser/diathermy near O2 in airway - especially in ENT/dental surgery

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a) Different Methods and Materials for Intra-operative Bleeding Control

• Pre-operative correction of coagulopathy
• Careful patient positioning
• Regional anaesthesia (reduces blood pressure)
• Controlled hypotension (MAP 50-65 mmHg in selected cases)
• Tourniquet (limb surgery)
• Preoperative autologous blood donation

• Digital pressure, packs (gauze packs, laparotomy pads)
• Direct pressure (10-15 minutes for liver)
• Vessel ligation (silk, absorbable sutures)
• Vascular clamps (bulldog, Satinsky, DeBakey)
• Tourniquet (Pringle manoeuvre for liver - clamp hepatoduodenal ligament)
• Haemostat clips (titanium, Ligaclips)
• Suture ligation, figure-of-8 sutures
• Tamponade packing (damage control surgery)

• Monopolar diathermy (coagulation mode, fulguration)
• Bipolar diathermy
• Argon beam coagulator (surface coagulation of liver, spleen)
• Harmonic scalpel
• LigaSure/EnSeal (vessel sealing up to 7 mm)

• Vasopressin infusion
• Antifibrinolytics: tranexamic acid (TXA), epsilon aminocaproic acid
• FFP, cryoprecipitate, platelets, packed red cells
• rFactor VIIa (NovoSeven): life-threatening refractory hemorrhage
• Fibrinogen concentrate
• Prothrombin complex concentrate (PCC)

• Selective arterial embolisation (hepatic artery embolisation, splenic artery, bronchial artery)
• Endovascular balloon occlusion (REBOA) for trauma

• Under-running of vessels
• Vascular reconstruction/repair
• Damage control surgery (pack, close, ICU resuscitation, return in 24-48h)
• Staged surgery

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b) Precautions in Use of Electrocautery Devices

1. Patient grounding: Dispersive pad well applied, large contact area, away from metal implants
2. Pacemaker/ICD patients: Use bipolar; programme pacemaker to asynchronous mode; keep monopolar use brief, away from device; have defibrillator ready
3. Flammable materials: Allow alcoholic prep to fully evaporate; keep drapes dry; in airway surgery, reduce FiO2 before activation
4. Laparoscopic specific:
   • Check insulation integrity before use
   • Avoid capacitive coupling (don't use monopolar through plastic cannula with metal trocar)
   • Direct coupling - never activate while in contact with another instrument
5. Site-specific: Avoid use on digits, penis; careful near bile ducts, ureters, bowel (delayed thermal injury)
6. Fire hazard: Active electrode in insulated quiver when not in use
7. Smoke evacuation: Electrosurgical plume is toxic and carcinogenic - evacuate
8. Power settings: Use lowest effective setting
9. Instrument inspection: Damaged insulation is a serious hazard
10. Minimize use near nerves: Use bipolar near facial nerve, RLN

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Measures for Reducing Errors in Surgical Practice

• WHO Surgical Safety Checklist (Sign-in, Time-out, Sign-out)
• Correct site marking (surgeon marks site before anesthesia)
• Informed consent - clear documentation
• Preoperative antibiotics at correct time
• Deep vein thrombosis prophylaxis

• Team briefings
• Time-out before incision (confirm patient, procedure, site, allergies, implant availability)
• Scrub nurse counts (instruments, swabs, needles) - before closure and at end
• Specimen labeling immediately
• Sign-out (verify specimens, equipment concerns, recovery handoff)

• SBAR (Situation, Background, Assessment, Recommendation) handover
• Structured post-op orders
• Early warning scores (NEWS) for deterioration detection
• Clear documentation, handover protocols

• Surgical audit and morbidity/mortality (M&M) meetings
• Root cause analysis of adverse events
• Simulation training
• Clinical governance frameworks
• Reporting culture (near-miss reporting, incident reporting)
• Standardized protocols and checklists
• Crew Resource Management (CRM) training

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SECTION 3: UROLOGY - TESTIS & SCROTUM

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a) Lymphatic Drainage of the Testis

• Para-aortic lymph nodes (retroperitoneal) at the level of L1-L2 (renal hilum level)
• Specifically the interaortocaval, pre-aortic, para-aortic, pre-caval nodes
• Right testis → primarily interaortocaval and right para-aortic nodes
• Left testis → primarily left para-aortic nodes (between aorta and left renal vein)

• Mediastinal nodes
• Supraclavicular nodes (Virchow's on left)

• Testicular tumours metastasize first to retroperitoneal lymph nodes (NOT inguinal)
• Scrotal violation (prior scrotal surgery, maldescended testis corrected via scrotal approach) adds inguinal node involvement risk
• Retroperitoneal lymph node dissection (RPLND) is both staging and therapeutic for testicular cancer
• Inguinal nodes are NOT involved unless there is scrotal skin involvement or prior scrotal surgery
• Explains why orchidectomy is performed via inguinal approach (not scrotal) to avoid disrupting lymphatics and causing inguinal metastases

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b) Differentiate Primary and Secondary Hydrocele

1. Vaginal hydrocele: Fluid between visceral and parietal layers of tunica vaginalis - most common
2. Congenital hydrocele: Communication with peritoneum via patent processus vaginalis; reducible, increases on crying
3. Infantile hydrocele: Processus patent up to deep ring but not into peritoneum
4. Encysted hydrocele of cord: Fluid in cord along processus, not communicating - presents as cystic swelling in groin
5. Secondary hydrocele: As above

• Jaboulay's operation: Sac everted behind testis and sutured; for large sacs
• Lord's plication: Sac plicated by multiple sutures; for thin, moderate sacs
• Eversion technique: Similar to Jaboulay's
• Aspiration: High recurrence; used only in unfit patients

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a) Acute Scrotal Pain in 25-Year-Old - Diagnosis and Management

1. Testicular torsion (most urgent - must be excluded)
2. Torsion of appendix testis (commonest cause of acute scrotum in adolescents)
3. Acute epididymo-orchitis
4. Strangulated inguinoscrotal hernia
5. Trauma (haematocele)
6. Fournier's gangrene
7. Idiopathic scrotal oedema (rare)

• History: Onset (sudden in torsion, gradual in epididymo-orchitis), age, prior similar episodes (intermittent torsion), sexual history (STI risk), fever, urinary symptoms
• Examination:
  • Testicular torsion: Transverse lie, high-riding testis, loss of cremasteric reflex, nausea/vomiting, extreme tenderness
  • Epididymo-orchitis: Fever, urethral discharge, tenderness localized to epididymis (posterior), cremasteric reflex usually present, Prehn's sign (elevation relieves pain) - unreliable
  • Blue dot sign (torsion of appendix testis): Blue/black tender nodule at upper pole

• Doppler ultrasound: Absent/reduced flow = torsion; increased flow = epididymo-orchitis
• Urine analysis and culture: For infection
• STI swabs: If epididymo-orchitis suspected
• Scrotal exploration: If torsion suspected clinically - DO NOT delay for investigations

• <6 hours: ~100% testicular salvage
• 6-12 hours: ~70%
• 12-24 hours: ~20-50%

• 24 hours: <10%

• Emergency scrotal exploration under GA
• Delivery of testis, untwist, assess viability (warm saline packs)
• Viable: orchidopexy (fix to dartos in 3 places with non-absorbable sutures)
• Non-viable: orchidectomy
• Contralateral testis: ALWAYS fix contralateral testis at same surgery (bell-clapper deformity is bilateral)

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Retroperitoneal Lymph Node Dissection (RPLND)

1. Staging: Clinical Stage I non-seminoma (NSGCT) - to detect micrometastatic disease (pathological upstaging from pN0 to pN1)
2. Therapeutic: CS IIA/IIB NSGCT (residual/involved retroperitoneal nodes)
3. Post-chemotherapy RPLND: Residual retroperitoneal mass >1cm after BEP chemotherapy in NSGCT (to resect viable tumour/teratoma/fibrosis)
4. Salvage RPLND: For relapsed retroperitoneal disease after chemotherapy failure
5. Seminoma: Residual mass >3cm post-chemotherapy (rare; more commonly PET-guided decision)

• Position: Supine, slight hyperextension (roll under lumbar region)
• Incision: Midline (xiphoid to pubis) or thoracoabdominal
• Exposure: Medial visceral rotation; right colon, small bowel mesentery reflected medially
• Templates:
  • Full bilateral template: From renal arteries (T11-12/L1) to common iliac bifurcation, between ureters
  • Modified template: Nerve-sparing (unilateral); right side = interaortocaval, right para-aortic; left side = left para-aortic only
  • Nerve-sparing preserves sympathetic efferent nerves L1-L4 for antegrade ejaculation
• Lymph node dissection along great vessels, removing all nodal tissue
• Preserve: Ureters, renal arteries/veins, IVC, aorta, sympathetic trunk (if nerve-sparing)

• Early: Bleeding (IVC, aorta, lumbar vessels), vascular injury, ureteric injury, lymphocoele, ileus, wound complications
• Late (most significant):
  • Retrograde ejaculation/anejaculation (40-75% with full template; <5% nerve-sparing)
  • Chylous ascites
  • Bowel obstruction (adhesions)
  • Ureteric obstruction

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a) Undescended Testis (Cryptorchidism)

1. Infertility: Bilateral > unilateral; high temperature impairs spermatogenesis (Sertoli cell function)
2. Malignancy: 3-8x increased risk of testicular germ cell tumour; most common malignant transformation in intra-abdominal testis; orchidopexy does not eliminate risk but facilitates self-examination
3. Torsion: Abnormal fixation predisposes
4. Trauma: Inguinal location vulnerable
5. Psychological: Cosmetic and psychological impact
6. Associated anomalies: Patent processus vaginalis (hernia ~90%), epididymal anomalies

• True undescended (cryptorchid): On normal path of descent
  • Intra-abdominal: Above deep ring
  • Intracanalicular: In inguinal canal
  • At deep ring
  • Emergent from superficial ring: most common (just beyond ring)
  • High scrotal: Upper scrotum
• Ectopic testis: Off normal path of descent; superficial inguinal pouch (most common ectopic), perineal, femoral, pubopenile, transverse

• Clinical examination (warm hands, cross-legged position or squatting)
• Ultrasound (inguinal region; poor for intra-abdominal)
• MRI/CT (if impalpable clinically)
• Laparoscopy: Gold standard for impalpable testis - therapeutic and diagnostic
• hCG stimulation test + serum Inhibin B/FSH: For bilateral impalpable (to determine presence of testicular tissue)
• Karyotype: If bilateral impalpable

• Timing: Surgery at 6-18 months (current recommendation); previously 2 years; early orchidopexy preserves fertility better
• Hormonal: hCG or GnRH (limited role, low success ~20%)
• Surgery (orchidopexy):
  • Standard: Herniotomy + mobilization + dartos pouch fixation in scrotum
  • If inadequate length: Fowler-Stephens technique (ligate testicular artery; relies on deferential/cremasteric collaterals) - staged or one-stage
  • Prentiss manoeuvre: Vessel pass medial to inferior epigastric vessels
  • Laparoscopic orchidopexy: For high undescended testes
  • Microvascular orchidopexy: Autotransplantation with microsurgical anastomosis
• If atrophic/absent: Orchidectomy + prosthesis (for cosmesis, in post-pubertal)

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a) Acute Scrotum in 11-Year-Old - Case Discussion

a) Differential Diagnosis

1. Torsion of testis (most likely - most dangerous)
2. Torsion of hydatid of Morgagni (appendix testis) - commonest cause in this age group
3. Acute epididymo-orchitis (less common in pre-pubertal boys)
4. Idiopathic scrotal oedema
5. Incarcerated/strangulated inguinoscrotal hernia
6. Traumatic haematocele
7. Henoch-Schönlein purpura (scrotal involvement)
8. Insect sting/allergic reaction

b) Clinical Diagnosis

• Sudden onset severe pain (young boy, physical activity like wrestling)
• Nausea/vomiting
• High-riding testis (shortened spermatic cord)
• Horizontal/transverse lie of testis
• Absence of cremasteric reflex (most reliable sign)
• Diffuse tenderness of entire testis
• Prior similar episodes

• Less severe, may localize to upper pole
• "Blue dot sign" visible at upper pole (pathognomonic, 20% cases)
• Cremasteric reflex present
• Tenderness localized to upper pole

• Gradual onset, fever
• Preceding UTI/urethritis
• Tenderness posterolateral (epididymis)
• Urinary symptoms

c) Investigations and Interpretation

1. Scrotal Doppler Ultrasound (most important):
   • Torsion: Absent or markedly reduced blood flow to affected testis
   • Epididymo-orchitis: Increased/hyperaemic flow
   • Torsion of appendix: Normal testicular flow + tender nodule at upper pole with whirlpool sign of twisted appendage
   • CRITICAL NOTE: If clinical suspicion is high for torsion, DO NOT wait for ultrasound - proceed directly to theatre. Ultrasound only if diagnosis is genuinely uncertain.
2. Urine analysis and culture: Pyuria/bacteriuria suggests infection; normal in torsion
3. FBC: Leukocytosis in infection; may be mild in torsion

• STI screen: Not relevant in 11-year-old
• Radionuclide scan (Tc-99m): "Cold spot" in torsion, "hot spot" in epididymo-orchitis; largely replaced by Doppler US; too slow

• Absent Doppler flow in 2-hour onset acute scrotum in 11-year-old = Torsion until proven otherwise
• Management: Emergency exploration under GA, bilateral orchidopexy if viable, orchidectomy + contralateral orchidopexy if non-viable

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a) Staging and Management of Testicular Tumours

Staging

• Stage I: Confined to testis (and its envelopes); no clinical/radiological/pathological evidence of disease beyond testis
• Stage II: Infradiaphragmatic lymph node involvement only
  • IIA: Max diameter <2 cm
  • IIB: 2-5 cm
  • IIC: >5 cm
• Stage III: Supradiaphragmatic lymph node involvement
  • IIIA: No mediastinal; abdominal involvement
  • IIIB: Mediastinal nodes
  • IIIC: Neck nodes
• Stage IV: Extralymphatic metastases (lung [IVLU, IVL1, IVL2, IVL3], liver, brain, bone)

• T1-T4: Tumour extent (T1: limited to testis; T2: lymphovascular invasion or epididymis; T3: spermatic cord; T4: scrotum)
• N0-N3: Regional lymph node involvement
• M0-M1b: Distant metastasis
• S0-S3: Serum tumour markers (critical for testicular cancer staging - unique to this TNM)
  • AFP (alpha-fetoprotein), beta-hCG, LDH

Management of 25-Year-Old with Suspected Right Testicular Tumour

• History: Painless scrotal swelling (hallmark), weight loss, back pain (retroperitoneal nodes), gynaecomastia (beta-hCG)
• Examination: Hard, non-transilluminable, irregular testicular mass; contralateral testis
• Serum tumour markers BEFORE orchidectomy: AFP, beta-hCG, LDH, PLAP
• Scrotal ultrasound: Confirm intratesticular mass, heterogeneous
• CT chest/abdomen/pelvis: Staging
• Chest X-ray

• Radical inguinal orchidectomy (NOT trans-scrotal): Via inguinal approach, high ligation of spermatic cord at deep ring, no scrotal violation
• Specimen for histology: Germ cell tumour (seminoma vs. NSGCT) determined
• Post-orchidectomy markers (after half-life clearance) - if rising, suggests residual disease

• Stage I: Surveillance (preferred) or para-aortic radiotherapy (20 Gy) or single-cycle carboplatin (AUC 7)
• Stage IIA: RT or BEP x 3 cycles
• Stage IIB-IV: BEP x 3-4 cycles
• Good prognosis marker: AFP normal (any elevation suggests NSGCT component)

• Stage IA (low risk: no LVI): Surveillance
• Stage IB/IS or high risk: BEP x 2 cycles or RPLND
• Stage IIA/IIB: RPLND or BEP x 3
• Stage IIC/III: BEP x 3-4 cycles
• Post-chemo residual mass >1cm: PC-RPLND
• BEP = Bleomycin + Etoposide + Cisplatin

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Classification and Management of Seminoma Testis

• Classic seminoma: 85%; large uniform cells, lymphocytic infiltrate
• Spermatocytic seminoma: 5%; older men, 3 cell types, very good prognosis, almost never metastasizes
• Anaplastic seminoma: 10%; highly mitotic, aggressive; high beta-hCG

• AFP: Always normal (any elevation = NSGCT component present)
• beta-hCG: Elevated in 15-20% (syncytiotrophoblast giant cells)
• PLAP: Elevated in 90%
• LDH: Non-specific

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Male Infertility - Causes and Management

• Hypogonadotropic hypogonadism (Kallmann's, pituitary tumour)
• Hyperprolactinemia
• Thyroid dysfunction
• Anabolic steroid use
• Androgen deficiency

• Varicocele (most common correctable cause, 15-40%)
• Cryptorchidism
• Klinefelter's syndrome (47,XXY): Azoospermia, gynaecomastia
• Orchitis (mumps, post-STI)
• Testicular torsion
• Radiation/chemotherapy
• Y chromosome microdeletions (AZFa, AZFb, AZFc)

• Obstructive azoospermia: Vasectomy, epididymal blockage, ejaculatory duct obstruction, CBAVD (congenital bilateral absence of vas deferens - CF related)
• Retrograde ejaculation (diabetes, RPLND, alpha-blockers)
• Erectile/ejaculatory dysfunction

• Semen analysis x2 (WHO 2021 criteria: volume >1.4ml, concentration >16M/ml, motility >42%, morphology >4% normal Kruger strict criteria)
• FSH, LH, testosterone, prolactin, thyroid
• Karyotype
• Y chromosome microdeletion testing
• Scrotal Doppler US (varicocele, testicular volume)
• TRUS (ejaculatory duct obstruction)
• Testicular biopsy (if azoospermia)

• Varicocele: Microsurgical varicocelectomy (subinguinal) - improves sperm parameters; reduces oxidative stress
• Obstructive azoospermia: Vasectomy reversal (vasovasostomy or vasoepididymostomy microsurgery); if obstructive - PESA/TESA + ICSI
• Non-obstructive azoospermia: Micro-TESE (microscopic testicular sperm extraction) + ICSI
• Hormonal causes: Gonadotropins (FSH, hCG) for hypogonadotropic hypogonadism
• Retrograde ejaculation: Alpha-agonists (pseudoephedrine), sperm retrieval from urine
• Idiopathic: Antioxidants (Vitamin E, C, CoQ10), empirical FSH, clomiphene - limited evidence; proceed to ART

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Vasectomy

Types of Vasectomy

1. Conventional vasectomy: Two small incisions (bilateral); vas identified, segment excised, ends ligated
2. No-scalpel vasectomy (NSV): Introduced by Li in China (1974); puncture with sharp forceps, no incision; lower complication rate, faster recovery, now preferred worldwide
3. Minimally invasive vasectomy (MIV): Similar to NSV
4. Fascial interposition: After excision, fascial sheath sutured between ends (reduces recanalization risk)
5. Mucosal fulguration: Cautery of mucosal lumen (reduces recanalization)

Complications of Vasectomy

• Haematoma (most common, 1-2%)
• Infection/wound dehiscence
• Vasovagal reaction during procedure
• Failure (early recanalization - rare, 0.4%)

• Chronic scrotal pain (post-vasectomy pain syndrome, ~15%)
• Sperm granuloma (inflammatory nodule at vas cut end due to sperm leakage)
• Congestive epididymitis
• Epididymal obstruction
• Antisperm antibodies (90-100% develop - significance uncertain)
• Recanalization (late failure, <1%)
• NOT associated with: Prostate cancer, cardiovascular disease, dementia (historical concerns refuted)

Criteria for Ideal Vasectomy Candidate

1. Completed family (2+ living children)
2. Understands and consents to permanence
3. Stable relationship (ideally; but individual autonomy respected)
4. Age >25 (some guidelines >30)
5. No coercion
6. Has considered and ruled out other contraceptive methods
7. Counseled about reversal rates and failure rates
8. Normal scrotal anatomy (no prior surgery, no varicocele - relative, can still be done)

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Microscopic Vasoepididymostomy

• Post-vasectomy epididymal obstruction (blowout)
• Congenital epididymal obstruction
• Post-infectious obstruction (STI, TB)

• Performed under operating microscope (15-25x magnification)
• Scrotal incision, deliver testis and epididymis
• Identify site of obstruction (dilated tubules above block)
• Open epididymal tubule with microscissors, identify sperm (some sent for cryopreservation)
• Two main techniques:
  • End-to-side invagination (two-suture): Most widely used; vas mucosal edge sutured to single epididymal tubule in invagination; 10-0 nylon
  • End-to-side triangulation (three-suture): Three sutures per anastomosis
• Anastomosis with 10-0 monofilament nylon
• Single epididymal tubule anastomosed to vasal lumen

• Patency rate: 60-87%
• Pregnancy rate: 30-56%
• Better results if performed by high-volume microsurgeons
• Results decline as obstruction level is more proximal (caput vs. cauda)

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SECTION 4: SKIN TUMOURS & INFECTIONS

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b) Partial Thickness vs Full Thickness Skin Grafts

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a) Marjolin's Ulcer

• Chronic irritation/inflammation → repeated cycles of damage and repair → accumulation of mutations in keratinocytes → malignant transformation
• Malignant change occurs after latent period of 20-40 years (average)
• Relatively avascular scar tissue limits immune surveillance (reduced immune reaction)
• Most common underlying conditions:
  • Burns scars (most common - Burn scar Marjolin's)
  • Chronic venous ulcers
  • Pressure ulcers
  • Osteomyelitis sinuses
  • Vaccination scars
  • Radiation-induced scars
  • Lupus vulgaris (TB scar)

• Long-standing ulcer/scar with change in character
• Raised, everted, rolled edges (distinguishes from typical venous ulcer)
• Friable, bleeding granulation tissue
• Foul-smelling discharge
• Painless (scar tissue is avascular/denervated) - important distinguishing feature
• Indurated base and edges
• Regional lymphadenopathy (late; nodes may be absent due to lymphatic destruction in scar)

• Biopsy (incision biopsy from edge): Confirms diagnosis
• Chest X-ray (lung metastases)
• CT scan (regional lymph nodes, distant mets)
• MRI if bone involvement suspected

• Wide local excision with 1-2cm clear margins (including deep fascia)
• Reconstruction: STSG, flap
• Lymph node dissection: Only if clinically involved (unlike standard SCC - elective dissection not routine due to lymphatic destruction in scar)
• Radiotherapy: As adjuvant for positive margins; primary for unresectable
• Prognosis: Worse than de novo SCC; 5-year survival ~35-50%

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b) Meleney's Ulcer (Meleney's Synergistic Gangrene)

• Occurs 1-2 weeks post-surgery (especially abdominal)
• Starts as small, painful wound area
• Three zones classically:
  • Central zone: Gangrenous, black, necrotic skin
  • Middle zone: Purple/violet discoloration (undermined edges)
  • Outer zone: Bright red, erythematous, painful advancing edge
• Slowly progressive (unlike Fournier's/NF which are rapidly spreading)
• Systemic symptoms usually mild initially

1. Wide surgical debridement of necrotic tissue (repeated if necessary)
2. Antibiotics: IV penicillin + anti-Staph (flucloxacillin) + metronidazole
3. Wound care, dressings
4. Nutritional support
5. Skin grafting after clean granulating wound established

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b) Kaposi's Sarcoma

1. Classic (Mediterranean): Elderly men of Eastern European/Mediterranean origin; indolent; lower extremity skin lesions
2. African (endemic): Sub-Saharan Africa; more aggressive; can involve lymph nodes
3. Iatrogenic (transplant-related): Post solid organ transplantation; immunosuppression-related; regresses if immunosuppression reduced
4. Epidemic (AIDS-related): Most common; CD4 <200 cells/μL; widespread skin + mucosal + visceral involvement; most aggressive

• HHV-8 infects endothelial cells → viral proteins (K-cyclin, vFLIP, vGPCR) drive uncontrolled proliferation → spindle cell tumour
• HHV-8 very common in Africa (50% seroprevalence); ~1-3% in Western countries
• In AIDS patients: immune deficiency allows HHV-8 reactivation → rapid progression

• Macules → papules → plaques → nodules progression
• Color: Pink → red → purple → brown
• Non-tender, non-pruritic lesions
• Distribution: Skin (face, nose, oral cavity, trunk, lower legs), oral mucosa (palate), GI tract, lungs (pulmonary KS - worst prognosis)
• Lymphedema due to lymph node involvement

• T0/T1: Skin +/- lymph node, no edema vs. edema/ulceration
• I0/I1: CD4 >200 vs. <200
• S0/S1: No systemic illness vs. systemic illness/constitutional symptoms

• Clinical diagnosis (characteristic appearance)
• Biopsy: Spindle cell proliferation with slit-like vascular spaces, RBC extravasation, inflammatory infiltrate; HHV-8 immunostaining positive
• HIV test, CD4 count, viral load
• CT/PET for staging
• Endoscopy/bronchoscopy if GI/pulmonary involvement

• AIDS-KS: HAART (antiretroviral therapy) is cornerstone - immune reconstitution causes regression of KS in many patients
• Local therapy: For limited cutaneous lesions: intralesional vinblastine, cryotherapy, laser, radiation, topical retinoids (alitretinoin gel)
• Systemic chemotherapy: Liposomal doxorubicin (Caelyx/Doxil) - first-line; paclitaxel (second-line)
• Reduction of immunosuppression: For transplant-related KS; switch from cyclosporine to mTOR inhibitor (rapamycin)
• Interferon-alpha: For classic/early epidemic KS

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a) Necrotizing Fasciitis

• Type I (polymicrobial, most common - 80%): Mixed aerobic and anaerobic organisms (Strep, Staph, Enterobacteriaceae, Bacteroides, Peptostreptococcus); typical in trunk, perineum (Fournier's), post-surgical, diabetic, elderly
• Type II (monomicrobial, Group A Strep - GAS): Streptococcus pyogenes alone (occasionally MRSA); limbs; previously healthy individuals; toxic shock syndrome; most rapidly fatal; hemolytic toxins (streptolysin S/O, Spe exotoxins)
• Type III (gas gangrene/clostridial myonecrosis): Clostridium perfringens; military wounds, deep lacerations; gas in tissue
• Type IV (fungal): Candida or Mucor; immunocompromised patients

• Entry point: minor trauma, surgical wounds, insect bites, IV drug use, perineal sepsis
• Bacteria produce enzymes (lecithinase, hyaluronidase, streptokinase) → spread along fascial planes
• Thrombosis of perforating vessels → skin ischemia → skin necrosis (late sign)
• Anaerobic fermentation → gas production (crepitus)
• Deceptive early: Skin looks normal while fascia is being destroyed (explaining diagnostic difficulty)

• Early: Swelling, erythema, pain out of proportion to appearance (pathognomonic), fever
• Late (advanced): Skin necrosis (brown/black), blistering, bullae (serous then haemorrhagic), crepitus, numbness (nerve ischemia), systemic sepsis
• Diagnostic clue: "Finger test" - at exploration, gloved finger passes easily along fascial plane (no resistance - fascial necrosis)
• LRINEC score (Laboratory Risk Indicator for Necrotizing Fasciitis): CRP, WBC, Hb, Na, creatinine, glucose - score ≥6 = suspicious

• Plain X-ray: Gas in tissues (not always present)
• CT scan: Gas in fascial planes, fascial thickening, fluid - sensitivity 88-93%
• MRI: Best imaging modality; but shouldn't delay surgery
• Operative exploration: Most definitive diagnosis
• Blood cultures, wound cultures, FBC, CRP, metabolic panel

1. Surgical debridement (EMERGENCY): Wide, radical excision of all necrotic/infected tissue; "look for bleeding edges"; debridement repeated every 24-48 hours until clean
2. IV antibiotics: Broad-spectrum:
   • Penicillin + clindamycin (for GAS - clindamycin inhibits toxin production)
   • Piperacillin-tazobactam + metronidazole + vancomycin (for polymicrobial)
   • Adjust based on cultures
3. ICU resuscitation: Fluid, vasopressors, organ support
4. IVIG: For streptococcal toxic shock syndrome
5. Hyperbaric oxygen: Adjunct (controversial, not universally available)
6. Reconstruction: STSG after clean granulating wound (weeks later)

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b) Fournier's Gangrene

• Severe perineal pain and swelling
• Fever, sepsis
• Skin crepitus (pathognomonic when present - ~20% cases)
• Erythema → skin necrosis (brown/black)
• Scrotum: Testes usually spared (separate blood supply from testicular artery, not pudendal)
• Foul-smelling necrotic tissue

1. Emergency radical debridement - do not delay; excise all necrotic tissue; spare testes (scrotal skin necrosis but testes viable - can be temporarily placed in medial thigh pouches)
2. Broad-spectrum IV antibiotics: As for NF Type I
3. ICU resuscitation
4. Colostomy/urinary diversion: If anorectal or urethral involvement
5. Repeat debridements: Every 24-48 hours
6. Hyperbaric oxygen: Adjunct (limited availability)
7. Reconstruction: STSG for scrotal defects (scrotum has excellent regenerative capacity)

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a) Classification and Staging of Malignant Melanoma

1. Superficial Spreading Melanoma (SSM) - 70%: Most common; radial growth phase initially; ABCDE pattern; back (men), legs (women); tan/brown with black, pink, red patches
2. Nodular Melanoma (NM) - 15-20%: Vertical growth phase from onset; rapidly growing; blue-black nodule, can be amelanotic; most aggressive
3. Lentigo Maligna Melanoma (LMM) - 5-10%: Elderly, sun-exposed skin (face, scalp); long radial growth phase (years); from lentigo maligna (in situ)
4. Acral Lentiginous Melanoma (ALM) - 5%: Palms, soles, subungual (Hutchinson's sign - nail fold pigmentation); no sun relation; most common in dark-skinned individuals; subungual - longitudinal melanonychia
5. Desmoplastic Melanoma: Fibrous stroma, neurotropic, associated with LMM, high local recurrence
6. Mucosal Melanoma: Oral, vaginal, anorectal - rare, poor prognosis
7. Uveal (Ocular) Melanoma: Choroid/ciliary body; does not follow SLNB; liver metastases

• T1a: <0.8mm, no ulceration
• T1b: <0.8mm + ulceration, OR 0.8-1.0mm ± ulceration
• T2a: 1.01-2.0mm, no ulceration
• T2b: 1.01-2.0mm + ulceration
• T3a: 2.01-4.0mm, no ulceration
• T3b: 2.01-4.0mm + ulceration
• T4a: >4.0mm, no ulceration
• T4b: >4.0mm + ulceration

• N0: No nodal metastasis
• N1a: 1 clinically occult node
• N1b: 1 clinically detected node
• N1c: No nodes, but in-transit/satellite/microsatellite metastases
• N2-N3: 2-3 or ≥4 nodes

• M0: No distant metastasis
• M1a: Distant skin, soft tissue, non-regional nodes (LDH normal)
• M1b: Lung metastasis
• M1c: Non-CNS visceral metastasis
• M1d: CNS metastasis

• Stage I: Localized, <2mm, no ulceration (IA) or with ulceration/1-2mm (IB)
• Stage II: Localized, >2mm or ulcerated T3-T4
• Stage III: Regional involvement (nodes, in-transit, satellite)
• Stage IV: Distant metastasis

• I: Epidermis only
• II: Into papillary dermis
• III: Fills papillary dermis
• IV: Into reticular dermis
• V: Into subcutaneous fat

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Risk Factors and Treatment

• UV exposure (sunburn history, tanning beds)
• Fair skin, red/blonde hair, blue/green eyes (phototype I/II)
• Multiple atypical/dysplastic nevi (>50 nevi increases risk)
• Giant congenital melanocytic nevus
• Personal/family history of melanoma
• Immunosuppression (transplant, HIV)
• CDKN2A, CDK4 mutations (familial melanoma)
• Xeroderma pigmentosum
• Breslow >1mm in prior thin melanoma

• Excision margins (AJCC/BAD guidelines):
  • In situ: 0.5-1 cm margin
  • <1mm: 1 cm margin
  • 1-2mm: 1-2 cm margin
  • 2-4mm: 2 cm margin

  • 4mm: 2-3 cm margin

• Sentinel Lymph Node Biopsy (SLNB): For tumours ≥0.8mm (or <0.8mm with high-risk features); lymphatic mapping with Tc-99m ± patent blue dye
• Completion lymph node dissection: No longer routinely done after positive SLN (MSLT-II, DeCOG-SLT trials showed no survival benefit); observation + surveillance preferred

• Targeted therapy (BRAF/MEK inhibitors):
  • BRAF V600E mutation (~50% of melanomas): Vemurafenib, dabrafenib (BRAF), trametinib, cobimetinib (MEK); combination is standard
• Immunotherapy (Checkpoint inhibitors):
  • Anti-PD-1: Pembrolizumab, nivolumab - first-line for Stage III/IV
  • Anti-CTLA-4: Ipilimumab
  • Combination nivolumab + ipilimumab: Superior response but higher toxicity
• For Stage IV: Ipilimumab + nivolumab or anti-PD-1 monotherapy for BRAF wild-type; BRAF+MEK inhibitors for BRAF mutant

• Excise with 1 cm margins (Breslow likely <1mm for 5mm diameter lesion)
• SLNB if Breslow ≥0.8mm
• Wide local excision + primary closure or STSG if large defect

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Premalignant Lesions of Skin

1. Actinic (Solar) Keratosis: Most common; scaly, erythematous patches on sun-exposed skin; 0.025-16% annual malignant transformation to SCC; treatment: cryotherapy, 5-FU, imiquimod, photodynamic therapy, diclofenac gel
2. Bowen's Disease (SCC in situ): Full-thickness epidermal dysplasia without dermal invasion; erythematous scaly plaque; can be HPV-associated; progression to invasive SCC ~10%; treatment: 5-FU, excision, PDT, cryotherapy
3. Erythroplakia (Queyrat's erythroplasia): SCC in situ on penis/vulva; high malignant transformation (30%); treatment: excision/circumcision/5-FU
4. Lentigo Maligna (Hutchinson's melanotic freckle): In situ melanoma; slowly enlarging pigmented macule on sun-damaged skin (face); transforms to LMM in ~5%; treatment: wide excision with 0.5-1cm margins; imiquimod for unresectable
5. Dysplastic (Atypical) Nevus: Irregular, large (>5mm), variably pigmented; risk marker for melanoma; multiple = "dysplastic nevus syndrome"; biopsy if concerning features
6. Leukoplakia: White patch in oral/genital mucosa; SCC transformation 1-20%
7. Keratoacanthoma: Rapidly growing squamous lesion; may be precursor of SCC; spontaneous resolution possible; treat as SCC
8. Arsenical keratosis: From chronic arsenic exposure; Bowen's disease, SCC risk
9. Xeroderma pigmentosum: AR; defective NER; extreme UV sensitivity; multiple skin cancers
10. Epidermodysplasia verruciformis: HPV-related; SCC transformation

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a) Basal Cell Carcinoma (BCC)

• Chronic UV exposure (most important) - UVB induced mutations in PTCH1 (Sonic Hedgehog pathway)
• Ionizing radiation
• Arsenic exposure
• Immunosuppression (organ transplant recipients)
• Gorlin's syndrome (Basal Cell Nevus Syndrome): PTCH1 mutation; multiple BCCs, jaw keratocysts, calcified falx cerebri, bifid ribs
• Xeroderma pigmentosum
• Most common in fair-skinned individuals; extremely rare in dark skin
• Age: Predominantly >50 years; increasing incidence in younger (tanning bed use)

1. Nodular BCC: Most common (60-80%); pearly, translucent nodule with rolled edges, telangiectasia, central ulceration; "rodent ulcer" when ulcerated
2. Superficial BCC: Erythematous scaly patch with thread-like pearly border; multiple; trunk; associated with BRAF mutation; treated with topical agents
3. Morphoeic/Sclerosing BCC: Flat, ivory/scar-like plaque; indurated; aggressive; poorly defined margins; high recurrence; requires Mohs surgery
4. Pigmented BCC: Blue-brown pigmented; nodular BCC variant; may mimic melanoma
5. Fibroepithelioma of Pinkus: Stalk-like fibromatous stroma with epithelial strands; trunk; benign behavior
6. Basosquamous (Metatypical): Features of BCC + SCC; intermediate behavior; higher metastatic potential than BCC

• Pearly, shiny nodule with rolled telangiectatic border
• Central umbilication → ulceration ("rodent ulcer")
• Location: Face (90%) - inner canthus, nasolabial fold, nose (commonest site), pre-auricular
• Slow growing, locally invasive
• Very rare metastasis (<0.1%)
• "Never mets, never dies" - local destruction of bone, orbit, brain if neglected

1. Biopsy to confirm (punch or shave)
2. Staging CT if deep bone/orbit involvement suspected
3. Surgery (treatment of choice):
   • Standard excision: 4-5mm margins for well-defined nodular; primary closure, flap, or FTSG
   • Mohs Micrographic Surgery (MMS): For high-risk BCC (morphoeic, recurrent, ill-defined margins, periocular/nasal/ear H-zone); staged excision with complete margin assessment; highest cure rate (>99%)
   • Reconstruct with FTSG (supraclavicular/post-auricular donor), rotation/transposition flap, or primary closure
4. Radiotherapy: Primary (if unfit for surgery, or patient declines) or adjuvant (positive margins, perineural invasion); effective but radiation field concerns
5. Hedgehog pathway inhibitors: Vismodegib, sonidegib - for locally advanced/metastatic BCC, Gorlin's syndrome; oral; significant side effects (muscle cramps, alopecia)
6. Photodynamic therapy/Imiquimod/5-FU: Only for superficial BCC; not for invasive nodular

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SCC of Skin - Risk Factors, Treatment, Prognosis

• Chronic UV exposure (most important)
• Ionizing radiation
• Chronic ulcers/burns (Marjolin's)
• Pre-existing lesions (actinic keratosis, Bowen's, leukoplakia)
• HPV infection (especially genital/perianal SCC)
• Immunosuppression (transplant recipients have 65-250x increased risk)
• Chemical carcinogens: Arsenic, coal tar, PAHs
• Chronic scars, chronic wounds
• Xeroderma pigmentosum
• Organ transplant recipients: Most common malignancy

• Low-risk: Well-differentiated, <2cm, not on high-risk locations, no perineural invasion
• High-risk: >2cm, poorly differentiated, perineural invasion, depth >4mm or Clark level IV-V, recurrent, on ear/lip/scalp, immunocompromised

• Hard, indurated plaque → nodule → ulcer with raised everted edges
• Location: Sun-exposed skin (face, back of hands, ears, lower lip), chronic wounds
• Chronic oozing, bleeding
• Tender (unlike BCC)
• Regional lymphadenopathy in ~5% at presentation (up to 50% in immunocompromised)

• T1: <2cm; T2: 2-4cm; T3: >4cm or minor bone erosion; T4a: Cortical bone/marrow; T4b: Skull base/axial skeleton

1. Surgery (standard): Wide local excision
   • Low-risk: 4mm margins
   • High-risk: 6mm margins
   • Mohs surgery: For high-risk, head and neck, perineural invasion
2. SLN biopsy: For high-risk lesions (>2cm, poorly differentiated, perineural)
3. Lymph node dissection: For clinical nodal involvement
4. Radiotherapy: Primary or adjuvant (positive margins, perineural invasion, unresectable, elderly)
5. Cemiplimab (anti-PD-1): FDA approved for locally advanced/metastatic cSCC not amenable to surgery/RT; landmark approval 2018
6. Pembrolizumab: Also approved for recurrent/metastatic cSCC

• Tumour size (>2cm worse)
• Histological differentiation
• Depth of invasion
• Perineural invasion (most significant for recurrence)
• Location (lip, ear, scalp worse)
• Lymph node involvement
• Immunosuppression
• Overall: 5-year cure rate >90% for low-risk; 50-70% for high-risk with nodes

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Necrotizing Skin Infections - Types

1. Necrotizing Fasciitis Type I (polymicrobial): Trunk, perineum, post-surgical (see above)
2. Necrotizing Fasciitis Type II (Group A Strep/monomicrobial): Limbs, healthy adults
3. Fournier's Gangrene: Genitoperineal NF (see above)
4. Clostridial Myonecrosis (Gas Gangrene): Clostridium perfringens; muscle involvement; bronze-green skin; gas bubbles in muscle (crepitus); very rapid; associated with contaminated wounds, bowel surgery
5. Ludwig's Angina: Bilateral submandibular, submental, sublingual space infection; usually from dental source; floor of mouth woody induration; airway at risk - emergency
6. Meleney's Gangrene: Superficial, slowly progressive synergistic gangrene (see above)
7. Progressive Bacterial Synergistic Gangrene: Similar to Meleney's; abdominal wall; post-op
8. Pyoderma Gangrenosum: Non-infectious; autoimmune; associated with IBD, rheumatoid; pathergy; treat with steroids/biologics

• Presentation: Bilateral submandibular swelling, elevated floor of mouth, trismus, drooling, impending airway compromise; fever, systemic sepsis; dental caries/recent dental procedure history
• Airway: PRIORITY - awake fibreoptic intubation, tracheostomy if intubation fails; difficult airway kit at bedside
• IV antibiotics: Penicillin + metronidazole ± gentamicin; co-amoxiclav; MRSA cover if needed
• Surgical decompression: Bilateral submandibular incisions (external) + intraoral drainage; drain all spaces (submandibular, sublingual, submental)
• Dental extraction: Source control
• ICU: Monitoring, steroids (controversial) for airway edema

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SECTION 5: RESEARCH METHODOLOGY & STATISTICS

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a) Surgical Audit

1. Structure audit: Resources available (staffing, equipment, facilities)
2. Process audit: What was done (adherence to protocols)
3. Outcome audit: Results of care (mortality, morbidity, readmission rates)

1. Identify a problem or topic (e.g., anastomotic leak rate)
2. Set standards/criteria (based on literature/guidelines)
3. Collect data (retrospective/prospective case notes review)
4. Compare practice against standard (gap analysis)
5. Implement change (education, protocol change)
6. Re-audit (close the loop - have changes worked?)
7. Continue cycle

• Audit: Compares current practice against known standards; no new knowledge generated; no ethics committee needed
• Research: Generates new knowledge; tests hypothesis; ethics committee required; randomization possible

• Peri-operative mortality audit
• Complication audit (SSI, DVT, anastomotic leak)
• Procedure-specific audit (e.g., TAPP vs. Lichtenstein hernia repair outcomes)
• National databases: NCEPOD (UK), NSQIP (USA), CSCN (UK vascular)

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b) Clinical Study Designs

• Gold standard for therapeutic interventions
• Participants randomly assigned to intervention or control
• Strengths: Eliminates selection bias, confounding; permits blinding; establishes causality
• Weaknesses: Expensive, time-consuming, ethical constraints, poor external validity (strict eligibility criteria), not feasible for rare outcomes

• Exposure groups followed forward in time to measure outcomes
• Prospective (follows forward) or Retrospective (historical records)
• Measures Relative Risk (RR)
• Strengths: Can study multiple outcomes; good for common exposures; establishes temporal sequence
• Weaknesses: Expensive, long follow-up needed, subject to loss to follow-up, not good for rare diseases

• Starts with outcome (cases vs. controls), looks backward for exposure
• Measures Odds Ratio (OR)
• Strengths: Efficient for rare diseases, quick, inexpensive, can study multiple exposures
• Weaknesses: Recall bias, selection of appropriate controls is difficult, cannot calculate incidence, limited to one outcome

• Snapshot in time; measures prevalence of both exposure and outcome simultaneously
• Measures Prevalence Ratio
• Strengths: Quick, cheap, good for public health planning
• Weaknesses: Cannot establish causality (temporal sequence unknown), prevalence-incidence bias, unsuitable for rare diseases

• Population-level data; not individual-level
• Ecological fallacy (group findings don't apply to individuals)

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a) P-value b) Confidence Intervals c) Standard Deviation

a) P-value

• The probability of obtaining results at least as extreme as the observed results, assuming the null hypothesis (H0) is true
• It does NOT measure the probability that H0 is true, or the size of the effect
• Conventional threshold: p < 0.05 (5% significance level) → reject H0 (result "statistically significant")
• p = 0.03 means: if H0 is true, 3% chance of getting these results by chance
• Limitations: p-value does not indicate clinical significance; large studies can have p<0.05 for clinically trivial effects; arbitrary 0.05 threshold; can be misinterpreted

b) Confidence Intervals

• A range of values (calculated from sample data) that is likely to contain the true population parameter with a specified probability (usually 95%)
• A 95% CI means: if we repeated the study 100 times, 95% of the CIs computed would contain the true population value
• Example: RR = 1.8 (95% CI 1.2-2.6) means true RR likely between 1.2-2.6
• CI does NOT cross 1.0 for RR/OR → statistically significant (analogous to p<0.05)
• Advantages over p-value: Provides effect size AND precision; shows clinical relevance; more informative

c) Standard Deviation (SD)

• A measure of the spread/variability of data around the mean
• SD = √(Σ(xi - x̄)² / (n-1)) [for sample]
• Large SD = data widely spread; small SD = data clustered around mean
• In a normal distribution: Mean ± 1 SD contains 68.2%; ±2 SD contains 95.4%; ±3 SD contains 99.7% of observations
• Standard Error of Mean (SEM): SD/√n; estimates precision of the sample mean as an estimate of population mean; used for confidence intervals

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b) Meta-analysis and Systematic Review

• Comprehensive, structured synthesis of all available evidence on a specific clinical question
• Protocol pre-registered (PROSPERO)
• PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines followed
• Steps:
  1. Formulate PICO question (Population, Intervention, Comparator, Outcome)
  2. Pre-register protocol
  3. Comprehensive literature search (multiple databases: PubMed, Cochrane, EMBASE, CENTRAL)
  4. Study selection (2 independent reviewers)
  5. Data extraction
  6. Quality assessment (Cochrane RoB tool for RCTs; GRADE for quality)
  7. Synthesis (narrative or statistical)

• Statistical technique to pool quantitative results from multiple studies
• Increases statistical power, resolves conflicting results
• Forest plot: Graphical display; each study as horizontal line (CI) with square (point estimate); diamond at bottom = pooled estimate
• Heterogeneity: I² statistic: <25% low, 25-75% moderate, >75% high heterogeneity; Q statistic
• Fixed-effects model: Assumes one true effect size; for homogeneous studies
• Random-effects model: Accounts for between-study variation; for heterogeneous studies; more conservative
• Publication bias: Funnel plot asymmetry suggests bias; Egger's test

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a) Levels of Evidence and Grades of Recommendation

• Quality of evidence: High → Moderate → Low → Very Low
• Strength of recommendation: Strong (1) or Weak/Conditional (2)
• Notation: 1A = Strong recommendation, high quality evidence (highest)

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a) Principles for Selecting a Good Surgical Research Topic

1. Feasibility (FINER criteria):
   • Feasible: Adequate subjects, technical expertise, time, money, equipment available
   • Interesting: To investigator (sustains motivation over years of training)
   • Novel: New finding, extends prior work, confirms/refutes prior work
   • Ethical: IRB/IEC approvable, respects patient rights
   • Relevant: To current clinical practice, surgical education, health policy
2. Clearly defined and focused: PICO question clearly formulated; not too broad
3. Important: Addresses a significant clinical problem; high disease burden, high cost, significant morbidity
4. Clinically relevant: Results should be applicable to clinical practice
5. Measurable outcomes: Primary and secondary endpoints clearly defined; measurable, reproducible
6. Available in your institution: Access to patient population, data, technology
7. Supervisor/mentorship: Experienced guide in the field
8. Time-bound: Completable within the thesis period (2-3 years for MS)
9. Ethical approvability: Not harmful to subjects; informed consent obtainable
10. Literature gap: Prior literature review showing the topic has not been adequately addressed

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b) Statistical Analysis Principles for Research

1. Define variables: Categorical (nominal, ordinal) vs. continuous (interval, ratio)
2. Descriptive statistics: Mean ± SD (normal data), median (IQR) for skewed; frequencies/percentages for categorical
3. Test normality: Shapiro-Wilk test, Kolmogorov-Smirnov, histogram/Q-Q plot
4. Choose appropriate test:
   • Two groups, continuous normal: Student's t-test (independent/paired)
   • Two groups, non-normal: Mann-Whitney U (non-parametric)

   • 2 groups, normal: ANOVA; non-normal: Kruskal-Wallis

   • Categorical: Chi-squared test; Fisher's exact (small numbers)
   • Survival: Kaplan-Meier curves, log-rank test, Cox proportional hazards
   • Diagnostic tests: Sensitivity, specificity, ROC curve, AUC
   • Correlation: Pearson (normal), Spearman (non-parametric)
5. Significance level: α = 0.05 (Type I error); power (1-β) = 80% or 90% (Type II error)
6. Confidence intervals: 95% CI for all point estimates
7. Intention-to-treat (ITT) analysis: All randomized patients analyzed in assigned group (even if crossover); preferred for primary analysis
8. Per-protocol analysis: Only compliant patients; secondary analysis
9. Multiplicity: Adjust for multiple comparisons (Bonferroni correction)
10. Software: SPSS, R, Stata, GraphPad Prism

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b) Types of Bias in Scientific Studies

• Sampling bias: Sample not representative of target population
• Volunteer bias: Participants who volunteer are healthier/more motivated
• Berkson's bias: Hospital patients as controls → over-represent sick people
• Healthy worker effect: Workers healthier than general population

• Recall bias: Cases better remember past exposures than controls (case-control studies)
• Observer bias: Assessor knows group allocation → differential recording
• Hawthorne effect: Participants change behavior when being observed
• Interviewer bias: Leading questions

• A third variable associated with both exposure and outcome → spurious association
• Control by: Randomization (RCTs), matching, restriction, stratification, multivariate analysis

• Lead time bias: Earlier detection gives illusion of longer survival
• Length bias: Slow-growing tumours disproportionately detected by screening
• Overdiagnosis bias: Detection of non-progressive lesions

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a) IMRAD Format of a Scientific Paper

• Background and context of the research problem
• Review of relevant literature (what is known)
• Identification of the knowledge gap/research question
• Objectives/hypothesis of the study
• Rationale for the study

• Study design (RCT, cohort, case-control)
• Setting, time period
• Study population: inclusion/exclusion criteria, sampling method
• Sample size calculation with justification
• Intervention/exposure details
• Outcome measures (primary, secondary)
• Data collection methods
• Statistical analysis plan
• Ethical approval, consent

• Flow diagram (CONSORT for RCTs, STROBE for observational)
• Baseline characteristics (Table 1)
• Primary outcome results
• Secondary outcomes
• Adverse events/complications
• Statistical analysis results (p-values, CI, RR/OR)
• Tables and figures

• Summary of main findings
• Interpretation in context of prior literature
• Comparison with similar studies
• Strengths of the study
• Limitations (important - critical for credibility)
• Implications for clinical practice
• Future research directions
• Conclusion: Concise summary statement

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a) Steps in Planning a Randomised Controlled Trial

1. Define research question (PICO format)
2. Literature review to confirm gap and justify trial
3. Hypothesis formulation: Null (H0) and alternative (H1)
4. Trial design: Parallel arm, crossover, factorial, cluster RCT
5. Define outcomes: Primary (one; most important), secondary (multiple); measurement tools; timepoints
6. Sample size calculation: Based on expected effect size, α error (0.05), power (80-90%), dropout rate (+10-20%)
7. Ethics committee (IEC/IRB) approval: Protocol, patient information sheet, consent form
8. Trial registration: ClinicalTrials.gov, CTRI (India), ISRCTN; MANDATORY before recruitment
9. Randomization:
   • Simple randomization (coin flip, random numbers)
   • Block randomization (ensures balance at intervals)
   • Stratified randomization (balance for important covariates, e.g., disease severity, centre)
   • Minimization (dynamic allocation)
10. Allocation concealment: Sequentially numbered sealed opaque envelopes (SNOSE), central telephone/web randomization; prevents selection bias
11. Blinding: Single (patient), double (patient + assessor), triple (patient + assessor + statistician); sham procedures
12. Recruitment: Screening, eligibility assessment, written informed consent
13. Data collection and management: CRF (Case Report Form), database, monitoring
14. Interim analysis and data safety monitoring board (DSMB): Pre-specified stopping rules
15. Statistical analysis plan (SAP): Pre-specified; ITT as primary; locked before data unblinding
16. Publication: CONSORT checklist; all outcomes reported

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Randomization Methods

1. Simple randomization: Random number table or computer-generated; no constraints; may produce unequal groups in small trials
2. Block randomization: Blocks of fixed size (e.g., blocks of 4 or 6); guarantees equal allocation at end of each block; variable block sizes prevent prediction
3. Stratified randomization: Stratify by important covariates (centre, disease severity) first, then randomize within strata; prevents imbalance in key variables
4. Minimization: Dynamic; each new participant allocated to minimize imbalance in stratification variables; preferred for multi-factor balance
5. Cluster randomization: Groups (clinics, villages) randomized, not individuals; used when individual randomization is impractical (community interventions); requires different statistical analysis (ICC)
6. Adaptive randomization: Allocation probability changes based on emerging results (response-adaptive randomization); ethical concern of giving fewer patients the better treatment

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a) Blinded Trial / b) Sample Size / c) Lead Time Bias / d) Systematic Review & Meta-analysis / e) Levels of Evidence

• A trial where one or more parties are unaware of which treatment group participants are in
• Single blind: Patient blinded (does not know treatment allocation)
• Double blind: Patient AND investigators/assessors blinded; gold standard for reducing bias
• Triple blind: Patient + investigator + statistician blinded
• Open-label: No blinding; introduces observer and performance bias
• Sham/placebo procedures: Used to blind participants in surgical trials (e.g., sham arthroscopy - Moseley trial)
• Purpose: Prevents performance bias (differential care), detection bias (differential outcome assessment), and placebo effect

• Necessary to ensure study is adequately powered to detect a real effect of a specified size
• Prevents Type I error (α): False positive (usually 0.05)
• Prevents Type II error (β): False negative; power = 1-β (usually 80% = β of 20%)
• Inputs needed: α (significance level), power (1-β), estimated effect size, baseline event rate, SD (for continuous outcomes)
• Formula (two proportions): n = (z α/2 + zβ)² [p1(1-p1) + p2(1-p2)] / (p1-p2)²
• Too small: Underpowered, misses real effects; too large: Wasteful, exposes more patients to inferior treatment
• Must account for expected dropout/non-compliance (inflate by 10-20%)
• Pilot studies provide estimates for main trial sample size

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Composition of Ethical Committee (IEC)

1. Chairperson: Independent (not from institution); credibility, leadership
2. Basic medical scientists (2-3): Pharmacologists, physiologists, biochemists
3. Clinicians: From relevant specialty and at least 2 other specialties
4. Legal expert: Understanding of medico-legal issues
5. Social/behavioural scientist or psychologist
6. Patient/community representative: Lay person (non-medical)
7. Member from NGO: Community welfare focus
8. Member secretary: Administrative support

• Review research protocols for scientific validity and ethical acceptability
• Ensure patient rights, safety, privacy
• Review consent forms
• Monitor ongoing trials
• Review adverse events
• Can suspend/terminate trials

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SECTION 6: BARIATRIC & METABOLIC SURGERY

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b) Indications and Contraindications of Bariatric Surgery

• BMI ≥40 kg/m² (Class III obesity) with or without comorbidities
• BMI 35-39.9 kg/m² + at least one significant obesity-related comorbidity:
  • Type 2 diabetes mellitus
  • Hypertension
  • Obstructive sleep apnoea
  • Obesity hypoventilation syndrome
  • GERD refractory to treatment
  • NAFLD/NASH
  • Dyslipidemia
  • Osteoarthritis (weight-bearing joints)
  • Infertility (PCOS)
  • Pseudotumour cerebri
  • Venous stasis
• BMI 30-34.9 kg/m² + T2DM (metabolic surgery - expanding indications): ASMBS/IFSO now endorse
• Indian subcontinent (OSSI 2008/2010 guidelines): BMI cut-offs lowered by 2.5 (BMI ≥37.5 without comorbidities; BMI ≥32.5 with comorbidities) given higher adiposity at lower BMI
• Age 18-65 years (relative; can be done outside this range selectively)
• Prior documented failure of non-surgical weight management (6-12 months)
• Psychological fitness: Understanding of risks, commitment to lifestyle change and follow-up

• Uncontrolled psychiatric illness (untreated schizophrenia, active substance abuse, severe depression)
• Active malignancy (relative - depends on prognosis)
• Uncontrolled eating disorder (binge eating without psychological support)
• Reversible endocrine cause of obesity (Cushing's syndrome, hypothyroidism) - treat first
• Inability to comply with post-operative requirements
• Child/adolescent (<18): Case-by-case; guidelines vary
• Severe cardiac, pulmonary, hepatic, or renal failure (increased operative risk)
• Pregnancy (absolute; must use reliable contraception for 12-18 months post-op)
• Portal hypertension (relative)
• Crohn's disease (relative - impacts bowel for bypass procedures)

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a) Types of Bariatric Surgery and Complications of Sleeve Gastrectomy

Types of Bariatric Procedures

1. Laparoscopic Sleeve Gastrectomy (LSG): Most common worldwide; remove ~80% of stomach along greater curvature over 36-40Fr bougie; banana-shaped gastric tube; no bowel anastomosis; also reduces ghrelin
2. Laparoscopic Adjustable Gastric Banding (LAGB): Silicone band around upper stomach; adjustable via subcutaneous port; reversible; now largely abandoned (poor long-term results, band-related complications)
3. Vertical Banded Gastroplasty (VBG): Historical; now abandoned

• Intragastric balloon: Temporary, BMI 27-40; bridge to surgery
• Endoscopic sleeve gastroplasty (ESG): Endoscopic suturing of greater curvature

Complications of Sleeve Gastrectomy

1. Staple line leak (1-3%): Most serious; presents as tachycardia, fever, abdominal pain; usually at gastroesophageal junction (highest pressure point); management: CT confirmation → IV antibiotics, drainage (percutaneous/surgical) ± self-expanding covered stent, nutritional support; mortality risk if uncontrolled sepsis
2. Haemorrhage (1-2%): Staple line bleeding; may need endoscopic treatment or re-operation
3. Pulmonary embolism (0.3-0.5%): Despite prophylaxis; obese patients at high risk; fatal in some
4. Deep vein thrombosis: Chemical prophylaxis (LMWH) + mechanical (TED stockings, early mobilization) essential
5. Wound complications: Port site infection, hernia (rare in laparoscopic)
6. Anastomotic/staple line stricture: Narrowing at incisura angularis; dysphagia; endoscopic dilatation

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a) Nutritional Consequences of Weight Loss Surgery

• Reduced total caloric intake
• Protein deficiency: Most important; goal ≥60g/day protein; deficiency causes muscle loss, hair loss, fatigue, wound healing impairment; supplement with protein shakes
• Fat malabsorption (RYGB/BPD): Steatorrhea, fat-soluble vitamin deficiency

• Dumping syndrome (RYGB mainly - Early: 10-30 min post meal - osmotic; Late: 1-3 hours - reactive hypoglycaemia)
• Reactive hypoglycaemia / nesidioblastosis: Late dumping; post-prandial hypoglycaemia; treatment: low-carbohydrate diet, acarbose, calcium channel blockers; rarely pancreatectomy
• Bone loss: Calcium + Vit D deficiency; monitor DEXA scan
• Alcohol use disorder: Increased risk post-RYGB (altered alcohol metabolism, addictive transfer)
• Wernicke's encephalopathy: Especially if prolonged vomiting post-op without thiamine supplementation

• Multivitamin (twice daily for RYGB/BPD; once daily for sleeve)
• Calcium citrate 1200-1500mg/day
• Vitamin D 3000 IU/day
• Vitamin B12 (monthly IM or 500mcg oral daily)
• Iron 45-60mg elemental/day (especially premenopausal women)

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a) Metabolic Surgery - Definition and Physiological Basis

• Bypassing duodenum and proximal jejunum prevents a putative "anti-incretin" signal that impairs insulin secretion and promotes insulin resistance
• The excluded segment normally produces an inhibitory factor (unknown) that worsens diabetes; its exclusion allows improvement
• Explains early T2DM resolution with RYGB before weight loss

• Rapid delivery of nutrients to distal ileum/colon stimulates L-cell secretion of:
  • GLP-1 (Glucagon-like peptide 1): Potent incretin; stimulates insulin secretion, suppresses glucagon, reduces appetite, slows gastric emptying
  • PYY (Peptide YY): Reduces appetite (ileal brake)
  • Oxyntomodulin
• Collectively: Enhanced incretin effect → improved beta-cell function, reduced insulin resistance

• Ghrelin (hunger hormone) produced mainly by gastric fundus
• Sleeve gastrectomy removes 80% of fundus → marked ghrelin reduction → reduced appetite, improved insulin sensitivity

• Post-bypass changes in bile acid circulation → altered FXR/TGR5 signaling → improved glucose metabolism, GLP-1 stimulation

• Anatomical rearrangement changes gut microbiota composition → reduced obesity-associated dysbiosis → improved metabolic parameters

• Contributes but does not fully explain early diabetes resolution

• RYGB: 37% complete remission at 5 years (vs. 10% intensive medical therapy)
• Sleeve gastrectomy: 25% remission at 5 years
• RYGB superior to sleeve for T2DM outcomes

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b) Preoperative Preparation - Diabetic, OSA, BMI 45, for Metabolic Surgery

• Full blood count, coagulation screen
• Renal function, liver function, electrolytes
• HbA1c (target <7.5-8% before surgery; ideally <6.5% for elective)
• Fasting lipid profile
• TFTs, cortisol (exclude secondary obesity)
• Vitamin D, calcium, iron, ferritin, B12, folate (baseline for post-op)

• ECG
• Echocardiography (if BMI >45, OSA, pulmonary hypertension suspected)
• Cardiology consultation if ECG abnormal or functional capacity poor

• Polysomnography (sleep study) - confirm OSA severity
• Pulmonary function tests
• CPAP compliance assessment
• Anaesthesia consultation: Difficult airway anticipated (high Mallampati, thick neck); video laryngoscope, awake fibreoptic intubation plan
• ABG (if severe OSA/obesity hypoventilation)

• Upper GI endoscopy: Mandatory before bariatric surgery (H. pylori testing and eradication; identify Barrett's/GERD/hiatus hernia/varices; important surgical planning)
• Abdominal ultrasound (gallstones - consider cholecystectomy if symptomatic)

• Dietary assessment by bariatric dietitian
• Pre-op VLCD (Very Low Calorie Diet) for 2-4 weeks: Reduces liver volume (steatosis), facilitates surgical exposure

• Formal psychological/psychiatric assessment: Ensure no active untreated disorder; realistic expectations

• Optimize glycaemic control: HbA1c <8% ideally; insulin regime may need dose reduction as intake decreases
• Liaise with endocrinologist
• Stop metformin 48h before (lactic acidosis risk, held perioperatively)
• Insulin adjustment plan for perioperative period
• Check for diabetic complications: Retinopathy, nephropathy (eGFR), neuropathy

• CPAP use pre-op (improves oxygenation, reduces pulmonary complications)
• Patient must use CPAP every night leading up to surgery
• Inform anaesthetist: Difficult intubation preparation
• Plan for post-op CPAP in recovery and ward

• VLCD (800-1000kcal/day) for 2-4 weeks: Reduces hepatomegaly, portal venous pressure, operative difficulty
• Liver weight can reduce 20-30% with 2-week VLCD

• Pre-op anaesthetic review mandatory
• Difficult airway assessment (Mallampati, thyromental distance, neck mobility)
• DVT prophylaxis plan (extended LMWH 7-10 days post-op)
• Pain management plan (multimodal, minimize opioids)

• Specific risks including anastomotic leak, VTE, nutritional deficiency, conversion to open
• Requirement for lifelong supplements and follow-up

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b) Risks Associated with Metabolic Surgery Procedures

• Mortality: 0.1-0.3% (comparable to laparoscopic cholecystectomy)
• Conversion to open: 1-5%
• Intra-abdominal bleeding
• Organ injury (spleen, liver, bowel)

• Internal hernia (RYGB): Through Peterson's space or mesenteric defects; closed loop obstruction; life-threatening; requires urgent laparoscopy; mesenteric closure at primary surgery reduces risk
• Marginal ulcer (RYGB): At gastrojejunal anastomosis; NSAIDs, smoking are risk factors; PPI mandatory post-op
• Anastomotic stenosis: Gastrojejunal junction
• Dumping syndrome: Early and late
• Reactive hypoglycaemia / nesidioblastosis

• Nutritional deficiencies (see above)
• Metabolic bone disease/osteoporosis
• GERD (sleeve)
• Alcohol use disorder
• Weight regain (especially sleeve; less with RYGB)
• Cholelithiasis (ursodeoxycholic acid for 6 months post-op)
• Pregnancy complications: Nutrient deficiencies, small for gestational age (delay pregnancy 12-18 months post-op)
• Psychological: Depression, body dysmorphia, deterioration of mental health in some

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b) Mechanism of Weight Loss After Sleeve Gastrectomy

1. Volume restriction: Gastric capacity reduced from ~1500ml to ~100-150ml → early satiety, smaller meals, reduced caloric intake
2. Ghrelin reduction (most important hormonal mechanism):
   • Gastric fundus removed (ghrelin-producing cells - X/A-like cells of oxyntic glands)
   • Ghrelin levels fall 60-70% post-sleeve
   • Ghrelin drives hunger and promotes fat storage (adipogenesis)
   • Reduction → decreased hunger, less appetite, reduced food-seeking behavior
3. Accelerated gastric emptying:
   • Liquid gastric emptying accelerated (unlike RYGB where it's markedly accelerated)
   • Enhanced delivery to small bowel → GLP-1, PYY secretion → satiety
4. Incretin effect (GLP-1, PYY):
   • Accelerated transit to distal small bowel
   • Increased L-cell stimulation → GLP-1, PYY release
   • GLP-1: Satiety, reduced gastric motility (late), improved insulin sensitivity
   • PYY: Ileal brake effect, satiety
5. Bile acid changes:
   • Altered enterohepatic circulation → TGR5 activation → GLP-1 secretion → metabolic improvement
6. Gut microbiome changes: Post-sleeve microbiome shifts contribute to metabolic improvement
7. Change in eating behavior: Patients develop new food preferences, reduced pleasure from eating high-calorie foods