Use of smooth muscle plasty after intersphincteric rectal resection to replace a partially resected internal anal sphincter: long-term follow-up

Abstract

Purpose: Patients with very low rectal cancer were treated by intersphincteric rectal resection employing partial internal anal sphincter resection. They then underwent smooth muscle plasty to restore internal anal sphincter function. We assessed the functional and oncological outcomes.

Patients and methods: Patients were selected if their biopsies revealed well-differentiated or moderately well-differentiated very low rectal tumors with distal tumor margins that permitted preservation of part of the internal anal sphincter. Functional results after closing the loop ileostomy were assessed by use of a standardized questionnaire. Continence was evaluated by use of the Kirwan score.

Results: Forty-seven patients with T2 to T3 very low rectal carcinomas underwent intersphincteric rectal resection and smooth muscle plasty that extended into the anal canal. All received neoadjuvant treatment. Postoperative morbidity was 38.3%. There were 46 R0 resections based on frozen section analysis; one patient achieved an R0 resection after reexcision of a positive distal margin on the frozen section. The median follow-up period was 67.2 months. One patient had local recurrence. The five-year overall and disease-free survival rates were 85% and 82%, respectively. Six months, one year, and two years after intersphincteric rectal resection, 80%, 87%, and 89%, respectively, had good continence (Kirwan I and II). Evacuation difficulty was detected in two patients with colonic S-pouches.

Conclusion: Providing neodjuvant treatment and preserving at least half of the functional internal anal sphincter mass produces acceptable oncological and functional outcomes in patients undergoing intersphincteric rectal resection for very low rectal cancer. However, whether smooth muscle plasty further improves postoperative continence should be tested by further studies.