Colorectal Surgery Practice Questions

Q: A patient is planned for elective colon surgery. What is the ideal timing for administration of prophylactic parenteral antibiotics?

1 hour before skin incision. ***1 hour before skin incision*** - Administering prophylactic antibiotics within **60 minutes** prior to the initial incision ensures adequate **tissue concentration** at the time of potential bacterial contamination. - Giving the dose too early risks the drug level dropping before the surgery begins, while giving it too late fails to protect during the highest risk period. *30 minutes before surgery* - While this timing falls within the acceptable window, it is not the **optimal** or widely recommended target compared to the 60-minute benchmark. - Depending on the specific antibiotic (e.g., **vancomycin** or **fluoroquinolones**), 30 minutes may not be sufficient for full infusion prior to incision. *2 hours before surgery* - Administering antibiotics 2 hours preoperatively significantly increases the risk that peak **serum levels** will be missed during the critical window of contamination. - Prolonged time intervals prior to incision are associated with higher rates of **surgical site infections (SSIs)**. *4 hours before surgery* - This duration is far too early; the drug will likely be cleared or metabolized below the **minimum inhibitory concentration (MIC)** required to prevent infection by the time the incision is made. - Prolonged preoperative administration does not provide additional benefit and may contribute unnecessarily to **antibiotic resistance**.

Q: A 65-year-old male with diabetes mellitus presents with purulent rectal discharge and is diagnosed with fistula-in-ano. Surgical management is planned. Which of the following procedures is considered internal anal sphincter-preserving?

Fistulectomy. ***Fistulectomy*** - A **fistulectomy** involves the complete excision of the **fistula tract** from its internal to its external opening, sparing the surrounding healthy **anal sphincter complex** when performed correctly. - It is the traditional standard for simple, low-lying **fistulae-in-ano** where the sphincter muscle involvement is minimal or superficial, thus preserving continence. *LIFT (Ligation of Intersphincteric Fistula Tract)* - The **LIFT** procedure is specifically designed to isolate and ligate the fistula tract in the **intersphincteric plane**. - While it preserves the sphincter, it is distinct from a formal **fistulectomy** and is often used for complex or **transphincteric fistulas** to avoid sphincter division. *FiLaC (Fistula-tract Laser Closure)* - **FiLaC** is a minimally invasive, sphincter-sparing technique that uses a **radial laser probe** to destroy the epithelial lining of the fistula tract. - It promotes healing of the tract from the inside out without requiring the division or excision of the **anal sphincter** muscles. *VAAFT (Video-Assisted Anal Fistula Treatment)* - **VAAFT** utilizes an **endoscope** (fistuloscope) to visualize the tract and fulgurate it under direct vision. - This procedure allows for the identification of lateral tracts and abscess cavities while strictly preserving the **anal sphincter** integrity.

Q: According to the American Association for the Surgery of Trauma (AAST) colon injury grading scale, how is a colonic laceration involving more than 50% of the bowel wall circumference without complete transection classified?

Grade III. ***Grade III*** - According to the AAST colon injury scale, a Grade III injury is defined as a colonic laceration encompassing greater than 50% of the bowel wall circumference, but short of complete transection. - This categorization is critical in trauma surgery for determining the necessity of more aggressive management strategies, such as resection, compared to simpler primary repair. *Grade II* - A Grade II colon injury is defined as a laceration involving 50% or less of the bowel circumference. - These injuries are generally associated with lower morbidity and often amenable to simple primary repair or stricture considerations. *Grade IV* - Grade IV injuries involve full-thickness transection of the colon. - This injury grade represents a higher level of tissue destruction requiring more complex management, usually involving formal resection rather than simple repair. *Grade V* - A Grade V injury pertains to a colon injury associated with **tissue loss** and **devascularization** of a colonic segment. - This is the most severe classification in the AAST scale and necessitates significant surgical intervention due to the compromised blood supply.

Q: On defecography, a rectocele is considered clinically significant when there is anterior bulging of the rectal wall into the posterior vaginal wall measuring more than:

2 cm. ***2 cm*** - A rectocele is defined as an anterior bulging of the rectal wall into the posterior vaginal wall, and it is considered clinically significant on **defecography** when this protrusion exceeds **2 cm**. - While smaller protrusions may be seen on imaging, they are often asymptomatic and do not require surgical intervention unless the patient presents with specific symptoms like **obstructed defecation**. *1 cm* - A rectocele measuring **1 cm** is typically considered to be within the range of physiologic or normal findings on defecography. - Many asymptomatic women show minimal bulging of this size, so it does not meet the criteria for **clinical significance** or surgical correction. *3 cm* - Although a **3 cm** rectocele would certainly fit the criteria for a clinically significant finding, it is not the minimum threshold for that clinical diagnosis. - Using a higher threshold would result in missing diagnosis and potentially undertreating patients who have symptomatic outlet obstruction related to a **2 cm** rectocele. *4 cm* - A **4 cm** rectocele is a large defect, but setting the diagnostic threshold this high would be inaccurate. - Clinical guidelines use the **2 cm** cutoff to balance diagnostic sensitivity with the correlation of patient-reported symptoms like **rectal digitation**.

Q: A 65-year-old man with chronic constipation and a history of psychiatric illness presents to the emergency department with sudden-onset abdominal distension, absolute constipation for 48 hours, and colicky central abdominal pain. His abdomen is tympanitic on percussion. Vital signs are stable. The plain erect abdominal X-ray is shown in Image 2. There is no peritonism on examination. What is the most appropriate initial management?

A. Rigid sigmoidoscopy and flatus tube decompression. ***A. Rigid sigmoidoscopy and flatus tube decompression*** - This patient presents with signs of **sigmoid volvulus**, characterized by the **"coffee-bean" sign** on X-ray, chronic constipation, and a history of psychiatric illness (possibly related to neuroleptic use). - In a **hemodynamically stable** patient without signs of **peritonitis** or intestinal ischemia, the first-line management is **non-operative decompression** using rigid sigmoidoscopy and insertion of a flatus tube. *B. Emergency Hartmann's procedure* - This is an invasive surgical procedure reserved for cases with evidence of **bowel gangrene**, **perforation**, or when endoscopic decompression is unsuccessful. - Performing an **emergency resection** as the first step in a stable patient increases morbidity unnecessarily compared to initial decompression. *C. Gastrografin enema to confirm and treat the obstruction* - While **Gastrografin enemas** are useful in diagnosing and treating **distal large bowel obstruction** or pseudo-obstruction, they are not the gold standard for managing volvulus. - Decompression via a **rectal tube** is more direct and effective for relieving the high-pressure gas accumulation in a sigmoid loop. *D. Colonoscopic decompression under general anaesthesia* - Flexible **colonoscopic decompression** is a secondary option if rigid sigmoidoscopy fails, but it does not typically require **general anesthesia**. - Starting with a complex procedure under anesthesia is inappropriate when **bedside rigid sigmoidoscopy** is less invasive and highly successful.

Q: A 62-year-old woman presents with a 4-month history of altered bowel habit, passage of blood mixed with stool, and a 6 kg unintentional weight loss. Colonoscopy was attempted but could not be completed due to a near-obstructing lesion in the descending colon. Her haemoglobin is 9.2 g/dL with a microcytic picture. She is clinically stable with no abdominal distension, peritonitis, or complete bowel obstruction. The barium enema is shown in Image 1. Staging CT confirms the lesion is confined to the bowel wall with no nodal or distant metastases (T2N0M0). Which of the following is the most appropriate surgical procedure?

A. Left hemicolectomy with primary anastomosis. ***A. Left hemicolectomy with primary anastomosis*** - This is the procedure of choice for a **localized tumor (T2N0M0)** of the **descending colon** in a stable, elective setting, allowing for curative resection and immediate restoration of bowel continuity. - The patient's lack of **peritonitis** or **acute complete obstruction** makes a primary anastomosis safe and appropriate for re-establishing the GI tract. *B. Hartmann's procedure with end colostomy* - This approach is typically reserved for **emergency settings**, such as **perforated diverticulitis** or fecal peritonitis, where a primary anastomosis would be unsafe. - Since the patient is clinically stable and undergoing a semi-elective procedure, a **permanent or temporary stoma** is not necessary as the first-line surgical option. *C. Abdominoperineal resection with permanent colostomy* - This procedure is specifically indicated for **low rectal cancers** that involve or are very close to the **anal sphincter** mechanism. - It is not anatomically relevant for a lesion located in the **descending colon**, which is significantly more proximal. *D. Transverse loop colostomy as definitive palliation* - This is a **palliative procedure** used to bypass an unresectable or obstructing lesion in patients who are not candidates for curative surgery. - The CT staging (T2N0M0) indicates the lesion is **resectable and localized**, making curative surgery with a **left hemicolectomy** the standard of care over simple diversion.

Q: Why should acute mechanical large bowel obstruction be operated on early?

Early gangrene and perforation. ### Explanation The primary reason for early surgical intervention in acute mechanical large bowel obstruction (LBO) is to prevent **early gangrene and perforation**, specifically at the **cecum**. #### 1. Why the Correct Answer is Right: The large bowel acts as a "closed loop" if the ileocecal valve is competent (found in 50-60% of cases). According to **Laplace’s Law** ($Pressure = Tension / Radius$), the tension is highest where the diameter is greatest. Since the cecum has the largest diameter in the colon, it is the most common site for ischemic necrosis and perforation. A cecal diameter **>10–12 cm** is a critical warning sign of impending perforation, necessitating urgent surgery to prevent fecal peritonitis, which carries a high mortality rate. #### 2. Why Other Options are Incorrect: * **A & B:** While electrolyte imbalances and septicemia occur, they are usually **late manifestations** or consequences of ischemia/perforation. In LBO, the colon's primary function is water absorption; thus, massive third-space loss is slower compared to small bowel obstruction. * **D:** Respiratory embarrassment due to diaphragmatic splinting occurs in massive distension (e.g., sigmoid volvulus), but it is rarely the primary indication for emergency surgery compared to the risk of bowel death. #### 3. Clinical Pearls for NEET-PG: * **Most common cause of LBO:** Colorectal Carcinoma (followed by Diverticulitis and Volvulus). * **Ogilvie’s Syndrome:** Pseudo-obstruction (no mechanical cause) that can also lead to cecal perforation; treated initially with Neostigmine. * **Bird’s Beak Sign:** Classic radiological finding in Sigmoid Volvulus. * **Management Priority:** If the cecum is distended and tender, it is a surgical emergency.

Question 1

A patient is planned for elective colon surgery. What is the ideal timing for administration of
prophylactic parenteral antibiotics?

Accepted Answer

1 hour before skin incision

Answer

30 minutes before surgery

Answer

2 hours before surgery

Answer

4 hours before surgery

Question 2

A 65-year-old male with diabetes mellitus presents with purulent rectal discharge and is
diagnosed with fistula-in-ano. Surgical management is planned. Which of the following procedures
is considered internal anal sphincter-preserving?

Accepted Answer

Fistulectomy

Answer

LIFT

Answer

FiLaC

Answer

VAAFT

Question 3

What is the fundamental surgical principle underlying TME in the operative management of
rectal cancer?

Accepted Answer

En bloc removal of the entire mesorectum as a single intact unit

Answer

Excision of only the peritumoral fat surrounding the tumor

Answer

Routine resection of the pelvic autonomic nerves

Answer

Ligation of the internal iliac artery

Question 4

According to the American Association for the Surgery of Trauma (AAST) colon injury grading
scale, how is a colonic laceration involving more than 50% of the bowel wall circumference without
complete transection classified?

Accepted Answer

Grade III

Answer

Grade II

Answer

Grade IV

Answer

Grade V

Question 5

On defecography, a rectocele is considered clinically significant when there is anterior bulging
of the rectal wall into the posterior vaginal wall measuring more than:

Accepted Answer

2 cm

Answer

1 cm

Answer

3 cm

Answer

4 cm

Question 6

A 65-year-old male with chronic constipation and a history of psychiatric institutionalisation presents with sudden-onset abdominal distension and absolute constipation for 48 hours. He has mild diffuse tenderness without peritoneal signs. HR 102 bpm, BP 118/74 mmHg, afebrile. His plain abdominal X-ray is shown (Image 1). What is the most appropriate next step in management?

Accepted Answer

B. Flexible sigmoidoscopic decompression followed by elective sigmoid resection

Answer

A. Emergency laparotomy and sigmoid resection with end colostomy

Answer

C. Urgent contrast enema to confirm the level of obstruction before any intervention

Answer

D. Nasogastric decompression and intravenous neostigmine infusion

Question 7

A 65-year-old man with chronic constipation and a history of psychiatric illness presents to the emergency department with sudden-onset abdominal distension, absolute constipation for 48 hours, and colicky central abdominal pain. His abdomen is tympanitic on percussion. Vital signs are stable. The plain erect abdominal X-ray is shown in Image 2. There is no peritonism on examination. What is the most appropriate initial management?

Accepted Answer

A. Rigid sigmoidoscopy and flatus tube decompression

Answer

B. Emergency Hartmann's procedure

Answer

C. Gastrografin enema to confirm and treat the obstruction

Answer

D. Colonoscopic decompression under general anaesthesia

Question 8

A 62-year-old woman presents with a 4-month history of altered bowel habit, passage of blood mixed with stool, and a 6 kg unintentional weight loss. Colonoscopy was attempted but could not be completed due to a near-obstructing lesion in the descending colon. Her haemoglobin is 9.2 g/dL with a microcytic picture. She is clinically stable with no abdominal distension, peritonitis, or complete bowel obstruction. The barium enema is shown in Image 1. Staging CT confirms the lesion is confined to the bowel wall with no nodal or distant metastases (T2N0M0). Which of the following is the most appropriate surgical procedure?

Accepted Answer

A. Left hemicolectomy with primary anastomosis

Answer

B. Hartmann's procedure with end colostomy

Answer

C. Abdominoperineal resection with permanent colostomy

Answer

D. Transverse loop colostomy as definitive palliation

Question 9

A 60-year-old male presented with bleeding per rectum. On digital rectal examination, a growth was palpable at the tip of the index finger. Sigmoidoscopy revealed an ulcero-proliferative growth located 6 cm from the anal verge. CECT showed no involvement of the liver or lungs. Following chemoradiation, what is the next best step in management?

Accepted Answer

Low anterior resection

Answer

Observation and follow-up

Answer

Abdominoperineal resection

Answer

Haman's procedure

Question 10

Why should acute mechanical large bowel obstruction be operated on early?

Accepted Answer

Early gangrene and perforation

Answer

Electrolyte imbalance due to third space loss

Answer

Septicemia from absorption of bowel contents

Answer

Respiratory embarrassment from massive abdominal distension

Colorectal Surgery — MCQs

Colorectal Surgery — MCQs

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