Postoperative anal canal length predicts outcome in patients having sphincter repair for fecal incontinence

PURPOSE: Controversy exists in regard to the prognostic value of clinical data and physiological tests in patients undergoing sphincter repair for fecal incontinence. The aim of this study was to identify prognostic factors. METHODS: Between 1986 and 1996, 405 consecutive patients had a sphincter repair for fecal incontinence. Preoperative and postoperative manometric data were available on 51 of these patients, and these patients' charts were reviewed retrospectively. Preoperative and postoperative continence was scored using the four-level scale of Browning and Parks. Mean follow-up was 16.2 (median, 6; range, 1–96) months. Mean age was 41 (median, 36; range, 21–80) years, and 46 (90 percent) patients were female. RESULTS: Twenty-three (45 percent) patients had perfect continence postoperatively, whereas 41 (80 percent) patients demonstrated improvement in continence score after sphincter repair. Using univariate analysis, various clinical and anal physiologic data were analyzed for an association with postoperative continence score. Postoperative mean resting pressure and postoperative anal canal length were both significantly related to postoperative continence (r_s^B for Spearman correlation coefficient to differentiate from r for the Pearson coefficient. =0.442;P=0.0012; andr_s=0.440;P=0.0012, respectively), whereas postoperative mean squeeze pressure was not (r_s=0.273;P=0.0529). Postoperative mean resting pressure and anal canal length were entered into a logistic regression model. Postoperative mean resting pressure was not significant (P=0.6643), and when it was dropped from the model, postoperative anal canal length was highly significant (estimated odds ratio, 3.2; 95 percent confidence interval, 1.1–9.3;P=0.0047) in predicting postoperative continence. CONCLUSIONS: No preoperative data predicted functional outcome, and in contrast to other studies, postoperative anal canal length provides the best prediction of postoperative continence.Read at the meeting of The American Society of Colon and Rectal Surgeons, San Antonio, Texas, May 2 to 7, 1998.