Mixed Deck — All FRCS Topics Flashcards

What is the concept of 'surgical margins' in oncological surgery, and why does an R0 resection matter?

Answer: R0 means microscopically clear margins; R1 means microscopic residual disease; R2 means macroscopic residual disease

The R classification describes completeness of surgical resection: R0 = complete resection with microscopically clear margins (curative intent achieved); R1 = microscopic residual tumour at margins; R2 = macroscopic residual tumour. R0 resection is the primary determinant of long-term cure in solid organ malignancies.

A patient who is a competent adult refuses an amputation that is likely to save their life from gas gangrene. What is the surgeon's legal and ethical obligation?

Answer: Respect the refusal, ensure the patient has full information, document extensively, and seek ethics support

A competent adult's refusal of treatment is legally and ethically binding, even when it results in death. The surgeon must ensure the decision is informed, not subject to undue influence, and made with capacity. Detailed documentation, ethics consultation, and support for the patient and family are essential.

In a patient with a large ventral hernia, which mesh position has the lowest recurrence rate?

Answer: Retromuscular (Rives-Stoppa: posterior to rectus muscle, preperitoneal)

The retromuscular (Rives-Stoppa) technique, placing mesh posterior to the rectus muscle in the retromuscular plane, achieves the lowest recurrence rates for complex ventral hernias. The mesh is held in place by intra-abdominal pressure and avoids direct bowel contact, reducing adhesion risk.

Which of the following is the most important buffer system in the extracellular fluid?

Answer: Bicarbonate-carbonic acid system

The bicarbonate-carbonic acid (HCO3-/H2CO3) system is the principal extracellular buffer. It is an open system: CO2 is regulated by the lungs and HCO3- by the kidneys, giving it enormous buffering capacity. Although the phosphate system is important intracellularly and in renal tubular fluid, and haemoglobin is the main intracellular buffer of red blood cells, bicarbonate dominates extracellularly.

A patient undergoes gastrectomy for gastric cancer. The pathology report describes a linitis plastica appearance. Which WHO histological subtype is most commonly associated with this macroscopic pattern?

Answer: Diffuse (poorly cohesive/signet ring cell) type

Linitis plastica (leather bottle stomach) is characterised by diffuse thickening and rigidity of the gastric wall. It is associated with the diffuse type (Lauren classification) or poorly cohesive/signet ring cell type (WHO classification). These tumours infiltrate submucosa and muscularis, inciting a desmoplastic stromal reaction. They carry a worse prognosis than intestinal-type tumours.

Which clotting factor has the shortest half-life and is therefore the earliest indicator of synthetic liver failure?

Answer: Factor VII

Factor VII has the shortest half-life of approximately 4–6 hours and is dependent on vitamin K and hepatic synthesis. The PT/INR, which is sensitive to Factor VII, is the most sensitive early indicator of hepatic synthetic failure and is incorporated into prognostic scoring (Child-Pugh, MELD, King's College Criteria).

A patient post-thyroidectomy develops perioral tingling and muscle cramps. Which complication has occurred?

Answer: Hypocalcaemia from hypoparathyroidism

Post-thyroidectomy hypocalcaemia results from inadvertent removal or devascularisation of the parathyroid glands during surgery, causing hypoparathyroidism. Symptoms include perioral and digital tingling (paraesthesiae), carpopedal spasm (Trousseau's sign), Chvostek's sign, and eventually tetany or seizures.

What type of collagen is predominantly synthesised during the proliferative phase of wound healing and replaced in the remodelling phase?

Answer: Type III collagen

Type III collagen (fine, immature) is predominantly produced during the proliferative phase of wound healing. During the remodelling phase (weeks to months), Type III collagen is gradually replaced by the stronger Type I collagen as wound tensile strength increases. The wound never regains 100% pre-injury strength (maximum ~80%).

A patient presents to the emergency department with a Glasgow Coma Scale (GCS) score of 8. According to ATLS principles, what airway intervention is indicated?

Answer: Definitive airway (endotracheal intubation)

A GCS of 8 or below indicates the patient cannot reliably protect their own airway and is at risk of aspiration. ATLS and UK resuscitation guidelines recommend definitive airway protection with endotracheal intubation (or surgical airway if intubation fails). The rule is 'GCS 8 — intubate.' Simple adjuncts may be used temporarily but do not provide definitive protection.

In the fasting state, which organ is the primary consumer of ketone bodies for energy?

Answer: Brain

During prolonged fasting, the brain adapts to utilise ketone bodies (beta-hydroxybutyrate and acetoacetate) for up to 70% of its energy needs. The liver produces ketone bodies but cannot utilise them as it lacks the enzyme succinyl-CoA:3-ketoacid CoA transferase. Red blood cells lack mitochondria and rely solely on glycolysis.

Which layer is entered first when performing a McBurney's point incision for appendicectomy?

Answer: External oblique aponeurosis

During open appendicectomy via a Gridiron incision at McBurney's point, the layers encountered are: skin → subcutaneous fat → Camper's fascia → Scarpa's fascia → external oblique aponeurosis → internal oblique (split in direction of fibres) → transversus abdominis → transversalis fascia → extraperitoneal fat → peritoneum.

What does the Montgomery ruling (2015) require regarding informed consent?

Answer: Patients must be informed of any risks a reasonable patient would want to know about, not merely what the clinician considers material

Montgomery v Lanarkshire Health Board (2015) replaced the Bolam-based approach to consent with a patient-centred standard: clinicians must disclose all material risks that a reasonable patient in that patient's position would want to know. This shifts the standard from 'what doctors consider material' to 'what patients consider material'.

In the context of evidence-based surgery, which level of evidence is provided by a well-conducted randomised controlled trial?

Answer: Level 1b

The Oxford Centre for Evidence-Based Medicine hierarchy classifies evidence: Level 1a = systematic review of RCTs, Level 1b = individual RCT (with narrow confidence interval), Level 2a = systematic review of cohort studies, Level 2b = individual cohort study, Level 3 = case-control study, Level 4 = case series, Level 5 = expert opinion. A single well-conducted RCT provides Level 1b evidence.

A new diagnostic test for bowel cancer has a sensitivity of 85% and a specificity of 90%. What does the specificity of 90% tell you?

Answer: 90% of patients without bowel cancer will test negative

Specificity is the proportion of truly disease-free individuals who test negative (true negative rate). A specificity of 90% means 90% of patients without bowel cancer will correctly test negative. The false positive rate is 10% (1 − specificity). High specificity minimises false positives.

Which Clostridium species is the primary causative organism of gas gangrene (clostridial myonecrosis)?

Answer: Clostridium perfringens

Clostridium perfringens produces alpha-toxin (phospholipase C), which destroys cell membranes and is the primary virulence factor in gas gangrene.

Which suture material is most appropriate for closing the linea alba in an emergency midline laparotomy?

Answer: Slowly absorbable monofilament (e.g., PDS/polydioxanone)

The STITCH trial (2015) and subsequent evidence support mass closure of midline laparotomies with a slowly absorbable monofilament suture such as PDS (polydioxanone), using a small-bite technique (5-8 mm from the wound edge, 5 mm apart) with a suture-to-wound-length ratio of at least 4:1. PDS maintains tensile strength for 6-8 weeks, matching the critical wound healing period. Monofilament reduces infection risk compared to braided sutures.

A patient in the intensive care unit has a central venous pressure of 14 mmHg, a mean arterial pressure of 55 mmHg, and a cardiac index of 1.8 L/min/m2. Which type of shock is most consistent with these findings?

Answer: Cardiogenic shock

The combination of elevated CVP, low MAP, and low cardiac index is characteristic of cardiogenic shock. The heart is failing as a pump, leading to fluid backing up (high CVP) with inadequate forward flow (low CI). Hypovolaemic shock would show low CVP. Warm septic shock typically shows high CI with low SVR.

Which type of renal cell carcinoma is most common, accounting for approximately 70-80% of cases?

Answer: Clear cell carcinoma

Clear cell renal cell carcinoma is the most common subtype (70-80%), arising from proximal tubular epithelium. It is strongly associated with VHL (von Hippel-Lindau) gene inactivation on chromosome 3p, leading to upregulation of HIF and VEGF. It characteristically shows cells with clear cytoplasm due to glycogen and lipid content. It is the subtype most responsive to anti-VEGF targeted therapies.

A 60-year-old man is ventilated in ICU with the following settings: FiO2 0.6, PEEP 10 cmH2O, tidal volume 450 ml (6 ml/kg IBW). His plateau pressure is 35 cmH2O. What is the driving pressure?

Answer: 25 cmH2O

Driving pressure = Plateau pressure - PEEP = 35 - 10 = 25 cmH2O. Driving pressure reflects the cyclical strain on the lung and is an independent predictor of mortality in ARDS. A driving pressure >15 cmH2O is associated with increased mortality. This patient's driving pressure of 25 cmH2O is concerning and may warrant reducing tidal volume or adjusting PEEP to improve lung compliance.

Which vasopressor is recommended as first-line in the management of septic shock according to the Surviving Sepsis Campaign guidelines?

Answer: Noradrenaline (norepinephrine)

Noradrenaline is the first-line vasopressor for septic shock (SSC 2021 guidelines). It is a potent alpha-1 agonist causing vasoconstriction with mild beta-1 effects supporting cardiac output. Vasopressin (up to 0.03 units/min) can be added as a second agent to reduce noradrenaline requirements. Dopamine is associated with more arrhythmias. Adrenaline is second-line when additional inotropy is needed.