FISTULOTOMY IN THE TREATMENT OF INTER-SPHINCTERIC ANAL FISTULA: IS THE RISK OF FECAL INCONTINENCE SIMILAR IN BOTH GENDERS, DESPITE ANATOMICAL DIFFERENCES?

Introduction Studies correlating sex with sphincter anatomy, the length of muscles divided after fistulotomy (FT), and fecal incontinence (FI) are incomplete.

Objective To evaluate the incidence of FI in patients undergoing FT to treat inter-sphincteric anal fistula and correlate symptoms, anatomical conformation of the anal canal, muscle length and percentage of divided muscles, and anal pressures, comparing genders.

Method A prospective cohort study included patients undergoing FT distributed by sex: GI = female and GII = male. Patients were evaluated before and after complete healing (between 2-3 months) for the Cleveland Clinic Incontinence Score (CCFIS); anal canal anatomy via 3D anorectal ultrasound (3D-US) [cm]: length of the anterior external anal sphincter (EAS); posterior EAS plus puborectal (EAS-PR); gap length (distance from the proximal edge of the anterior EAS to the proximal edge of the posterior PR); length of the anterior and posterior internal anal sphincters (IAS); length and percentage of divided IAS and divided angle; and anal pressures via manometry (mmHg). Groups were compared, and measurements were correlated with FI scores. The Student's t-test, Wilcoxon test, chi-square test, and Spearman's correlation coefficient (ρ) were used.

Results Of the 81 patients: 35 (43%) female and 46 (57%) male. The average age, trajectory distribution, and internal opening position were similar. The muscle length is longer and the gap shorter in men (p < 0.00). Additionally, the length of the divided IAS is greater in men (1.6 vs. 1.3/p < 0.00), and there was a positive correlation between CCFIS and the length of the divided IAS (r = 0.41/p < 0.00). However, the percentage of divided IAS, the incidence of FI (54% vs. 50%), and the score (1.8 vs. 1.9) were similar. The maximum contraction pressure was higher in GII (p < 0.005). Resting pressure decreased when comparing before and after surgery in both groups (p < 0.05).

Conclusion The risk of FI after fistulotomy was similar between sexes, despite differences in the anatomical conformation of the anal canal, such as longer muscle length in men, associated with a greater length of the divided IAS muscle (cut) during fistulotomy. In females, the muscle length is shorter, and the divided IAS muscle is smaller, so the percentage of divided IAS is similar in both sexes. The incidence of FI was high, with 50% of patients in both groups. However, the symptoms were mild.

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Artikel online veröffentlicht:
25. April 2025