Is a colonoscopy (colon examination using a flexible tube with a camera) necessary before colostomy (creation of an opening in the colon to divert fecal matter) reversal?

Colonoscopy Before Colostomy Reversal

A colonoscopy is necessary before colostomy reversal to examine the distal bowel segment for abnormalities, ensure anastomotic integrity, and detect any potential pathology that could complicate reversal surgery. 1, 2

Rationale for Pre-Reversal Colonoscopy

Detecting Abnormalities in Diverted Bowel

• Endoscopic examination of the colon distal to a colostomy reveals abnormal findings in approximately 80% of patients 2
• These abnormalities can range from benign mucous plugs to serious conditions like polyps or carcinoma
• High incidence of diversion colitis occurs in the excluded colon segment

Guideline-Based Recommendations

The American Cancer Society and US Multi-Society Task Force on Colorectal Cancer guidelines emphasize the importance of colonoscopic evaluation in patients with colorectal conditions, particularly:

1. For patients with non-obstructing tumors, preoperative colonoscopy should be performed 1
2. For patients with obstructing colon cancers who had alternative imaging initially, colonoscopy should be performed 3-6 months after resection 1
3. Regular surveillance is recommended following colorectal cancer resection, with specific timing intervals (1 year after resection, then 3 years, then 5 years if normal) 1

Clinical Approach to Pre-Reversal Evaluation

Step 1: Assess the Diverted Segment

• Evaluate for symptoms related to the excluded bowel (present in nearly half of patients) 2
  • Common symptoms: discomfort, pain, bleeding, discharge
  • Note that severe colitis or tumors may be asymptomatic

Step 2: Perform Complete Colonoscopic Examination

• Examine the entire colon distal to the colostomy
• Pay special attention to:
  • Mucous plugs or scybala (which should be treated by irrigation)
  • Polyps or carcinoma (which should be treated as in non-diverted colon)
  • Signs of diversion colitis (which can be treated with local steroids)

Step 3: Evaluate Anastomotic Site (if applicable)

• Ensure integrity of any previous anastomosis
• Check for strictures or other abnormalities that might complicate reversal

Special Considerations

Timing of Colonoscopy

• Perform colonoscopy 2-4 weeks before planned reversal surgery
• This allows time to address any findings that might affect the reversal procedure

Common Pitfalls to Avoid

1. Skipping colonoscopy before reversal: This can lead to missed pathology and complications during or after reversal
2. Inadequate bowel preparation: The diverted segment may require more aggressive preparation
3. Failing to treat identified abnormalities: Conditions like diversion colitis or polyps should be addressed before reversal

Post-Reversal Considerations

• Patients with prior colorectal cancer require ongoing surveillance according to established guidelines 1
• Patients may experience altered bowel function after reversal, requiring supportive management

Conclusion

Colonoscopy before colostomy reversal is an essential step to ensure optimal outcomes. It allows for detection and treatment of abnormalities in the diverted bowel segment, which are present in the majority of patients, and helps prevent complications during and after reversal surgery.