Comparative Evaluation Between Cutting of the Intersphincteric Space vs Cutting Seton in High Anal Fistula: A Randomized Controlled Trial.

Background: This study compared the efficacy of cutting of the intersphincteric space (COIS) with cutting seton (CS) procedure in treating high anal fistula.

Methods: Patients diagnosed with high anal fistula were allocated into groups, who randomly received COIS and CS procedures. The primary outcome was wound healing time. Secondary outcomes included surgical parameters (operation time, hospital stay, and hospitalization expense), anal sphincter function, wound pain, wound size, clinical efficacy, recurrence after 12 months of follow-up, and complications.

Results: A total of 72 patients participated (36 in each group). The wound healing time was notably shorter in the COIS group than the CS group (35.75 ± 11.15 vs. 55.69 ± 13. 42 days; P< 0.001). The COIS group also demonstrated superior basic surgical parameters compared to the CS group (P< 0.001). Postoperatively, the COIS group exhibited significantly higher anal resting pressure and anal maximum contractile pressure than the CS group at 3 months postoperatively (58.39 ± 6.72 vs. 51.25 ± 4.33 mmHg; P< 0.001 and 143.72 ± 8.25 vs. 126.75 ± 11.49 mmHg; P< 0.001). The Wexner incontinence score at 3 months post-operation in the COIS group was significantly lower than in the CS group (0.50;0.00,1.00 vs. 3.00; 3.00,4.00; P< 0.001). The recurrence rate was 2.78% in the COIS group and 8.33% in the CS group without statistically difference (P= 0.607).

Conclusion: In comparison to the CS procedure, COIS appears to be an effective treatment option for high anal fistulas, offering quicker wound healing time, enhanced sphincter function, less pain, minimal invasiveness, and cost-efficiency, while maintaining a high healing rate and low recurrence rate.