Short- and long-term outcome of surgical sphincteroplasty for anal incontinence

Abstract

Objective: Anal incontinence (AI) is an underreported and burdensome condition, often associated with reduced quality of life in those affected. Despite the introduction of newer and less invasive therapies, surgical sphincteroplasty remains an important treatment option. The purpose of this study was to assess the 1- and 5-year outcome in patients who had undergone surgical sphincteroplasty for AI in Norway.

Methods: This retrospective cohort study is based on prospectively recorded data from the Norwegian Register for Anal Incontinence. Data was available for baseline, year 1 and year 5. Patients with available results at baseline and year 1 were deemed the short-term group, while patients with results at baseline, year 1 and year 5, the long-term group. St. Mark´s score was used to determine degree of AI, and quality of life score (Qol) for evaluating well-being. Primary outcome was reduction in St. Mark´s score at year 1 and year 5, while secondary endpoints involved considering various baseline characteristics and their impact on outcome.

Results: There were 83 patients in the short-term group and 19 in the long-term group. Between baseline and year 1 there was a mean decrease in St. Mark´s score of 3.7 points in the short-term group and 7.1 points in the long-term group. There was a mean increase in the Qol of 0.59 and 1 points in each of the groups, respectively. Between year 1 and year 5 the mean St. Mark´s score increased by 2.5 points and the mean Qol decreased by 1.4 points. Comparing baseline with year 5, there was still a mean decrease in the St. Mark´s score of 4.6 points, and 14 of the patients (74%) reported a lower St. Mark´s score and less symptoms than at baseline. The mean Qol decreased by 0.5 points. A low St. Mark´s score at baseline was found to be statistically significantly associated with less reduction in the St. Mark´s score short-term. Neither age, menopause or extent of sphincter injury were prognostic of outcome.

Conclusion: Surgical sphincteroplasty is successful in improving symptoms of AI. Few patients achieved complete continence, but there was a significant improvement in symptoms and in the QoL at year 1. By year 5 most patients had experienced an increase in symptoms, however, 75% of the patients still had a lower St. Mark´s score than before the surgery. The results suggest that despite there being a time-dependent decline in success, sphincteroplasty was worthwhile for most patients. The only factor predictive of outcome was the baseline St. Mark´s score, which was significantly associated with poorer short-term result in patients with a low pre-operative score. Our results suggest that patients with a baseline St. Mark´s score of 12 or less have little to no benefit from surgical sphincteroplasty.