FRCS Principles of Surgery & Wound Healing 2 — Questions and Answers
Question 1: Which organism is the most common cause of wound infection in colorectal surgery?
- Staphylococcus aureus
- Escherichia coli
- Bacteroides fragilis (Correct answer)
- Pseudomonas aeruginosa
Correct answer: Bacteroides fragilis
Bacteroides fragilis is the most common organism isolated in post-operative wound infections following colorectal surgery. It is a Gram-negative anaerobe from the colonic flora. Broad-spectrum prophylaxis (e.g., metronidazole plus cephalosporin) covers both aerobic and anaerobic bowel flora.
Question 2: In a patient with a large ventral hernia, which mesh position has the lowest recurrence rate?
- Onlay (above the anterior rectus sheath)
- Inlay (within the defect, suture to fascial edges)
- Retromuscular (Rives-Stoppa: posterior to rectus muscle, preperitoneal) (Correct answer)
- Intraperitoneal underlay
Correct 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.
Question 3: What is the Principles of ERAS (Enhanced Recovery After Surgery) protocol aimed at?
- Reducing operative time by reducing surgical steps
- Reducing the physiological stress of surgery by perioperative optimisation to accelerate return of function (Correct answer)
- Eliminating the need for analgesics post-operatively
- Avoiding all fluid administration during surgery
Correct answer: Reducing the physiological stress of surgery by perioperative optimisation to accelerate return of function
ERAS (Enhanced Recovery After Surgery) protocols use multimodal evidence-based perioperative care pathways — including preoperative carbohydrate loading, minimal bowel prep, regional anaesthesia, early mobilisation, early oral intake, and avoidance of drains/NG tubes — to reduce the metabolic stress response and accelerate recovery.
Question 4: A patient post-thyroidectomy develops perioral tingling and muscle cramps. Which complication has occurred?
- Thyroid storm
- Recurrent laryngeal nerve injury
- Hypocalcaemia from hypoparathyroidism (Correct answer)
- Wound haematoma
Correct 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.
Question 5: Which type of wound closure is most appropriate for a severely contaminated wound from a perforated bowel?
- Primary closure with interrupted sutures
- Delayed primary closure (closure at 4–5 days if no infection) (Correct answer)
- Immediate closure over a drain
- Immediate skin stapling with prophylactic antibiotics
Correct answer: Delayed primary closure (closure at 4–5 days if no infection)
Contaminated or dirty wounds (e.g., from perforated bowel, faecal contamination) should not be closed primarily due to the high risk of wound infection and dehiscence. Delayed primary closure (at 4–5 days) allows the wound to be cleaned and monitored before closure when infection risk has reduced.
Question 6: What does the term 'physiological dead space' mean in relation to ventilation?
- The volume of gas in the airways that never reaches the alveoli (anatomical dead space)
- The total volume of ventilated lung that does not participate in gas exchange, including alveoli with no perfusion (Correct answer)
- The volume of gas left in the lungs after maximum expiration
- The residual capacity of the lung after normal exhalation
Correct answer: The total volume of ventilated lung that does not participate in gas exchange, including alveoli with no perfusion
Physiological dead space (Bohr dead space) is the total volume of ventilated lung not involved in gas exchange — it includes anatomical dead space (airways) and alveolar dead space (alveoli ventilated but not perfused). Physiological dead space is increased in pulmonary embolism, ARDS, and emphysema.
FRCS Principles of Surgery & Wound Healing 2
Which organism is the most common cause of wound infection in colorectal surgery?