EPD509 - Long-term Incontinence in Female versus Male Patients After Lateral Internal Sphincterotomy: A Systematic Review and Meta-analysis

Purpose/Background: In the treatment of chronic anal fissure (CAF), Lateral Internal Sphincterotomy (LIS) has been shown to be extremely effective in curing CAF but carries the risk of long-term fecal incontinence. It has been hypothesized that LIS may carry a higher risk of continence disturbance in females due to anatomical differences in pelvic floor composition and sphincteric trauma from vaginal delivery. Although this sex-based disparity in fecal incontinence has been qualitatively observed in clinics and is supported by several small retrospective studies, research dedicated to this topic remains limited. We performed this systematic review and meta-analysis, which to our knowledge is the first of its kind, to elucidate the respective risk of fecal incontinence in male and female patients who are status post LIS.

Methods/Interventions: The systematic review and meta-analysis were performed in accordance with PRISMA guidelines. The databases PubMed, Scopus, Cochrane Register of Controlled Trials (CENTRAL), and Ovid were queried for key terms associated with CAF and the LIS procedure. Thirty-seven prospective cohort, retrospective cohort, and randomized controlled trials investigating our primary outcome, fecal incontinence after LIS, were deemed appropriate for inclusion. The pooled incontinence proportion with 95% confidence intervals (CI) were calculated separately for males and females using a mixed effects logistic regression model to account for heterogeneity across studies, and heterogeneity was evaluated using the I² statistic. Analyses were performed using Stata statistical software.

Results/Outcomes: A total of 2668 studies were screened and 37 studies (n = 4033) fulfilled the criteria for inclusion. There were 16 randomized controlled trials, 10 retrospective cohort studies, and 11 prospective cohort studies. The mixed effects logistic regression models estimated the pooled rates of incontinence in male and female patients to be 1% and 4%, respectively. The mean follow-up ranged from 4 to 128 months, and mean age was 31 to 50.6 years across studies. The open and closed techniques were employed by 23 and 7 studies, respectively; 4 studies used both open and closed techniques, while 3 were unspecified. Eight studies utilized the modified technique (up to the fissure apex), 17 procedures were classically performed (up to the dentate line), 1 study utilized both methods, and 11 were unspecified. Procedures were done under local, general, or spinal anesthesia. Healing rates were 85% to 100%, while patient satisfaction rates were 89.1% to 100%. The incidence of abscess formation ranged from 0% to 7.5% across studies, while fissure recurrence rates were 0% to 15%. The mean long-term postoperative incontinence rate was 4.2%, which includes incontinence to flatus, liquid, and stool. Incontinence was evaluated with the Pescatori Incontinence Scale or the Wexner Incontinence Score/Cleveland Clinic Incontinence Score.

Conclusion/Discussion: Although fecal incontinence rates are low, female patients undergoing LIS for CAF experience an approximately four-fold higher rate of long-term incontinence when compared to male patients undergoing the same procedure. This finding should be taken into account when considering treatment management for patients with anal fissure.

Figure 1. Forest plot of studies reporting incontinence in females after LIS
Figure 2. Forest plot of studies reporting incontinence in males after LIS