Anterior sphincteroplasty for fecal incontinence: predicting incontinence relapse.

Purpose: This study was designed to evaluate the efficiency of anterior sphincteroplasty in preventing fecal incontinence relapsing in 85 female patients.

Methods: This observational study followed individuals for up to 10 years after intervention. Fecal incontinence relapse was analyzed using Generalized Linear Models and Kaplan-Meier tables. Bias due to informative censoring and missing data were assessed. Two postoperative cutoff Wexner scores (4 and 8) were used to classify individuals into continent or incontinent, and their model implications were examined.

Results: The hazard of relapsing appeared constant over time. This led to exponential time-to-relapse functions, and a linear increase of cumulative hazard over time. Predicted median relapsing time was 33 years, and overall risk 0.09 ± 0.03, when using a cutoff Wexner score of 8 (moderate), and 5 years, overall risk 0.45 ± 0.05, when using a cutoff of 4 (mild). There was a potential underestimation in parameters (bias) due to informative censoring, i.e., individual with better prognoses were more likely to drop out before relapsing compared to those with worse prognoses. Thus, true relapsing times may be longer than our current estimates.

Conclusions: The predictive model can be used in practice for individual prognosis after intervention, based on preoperative Wexner scores. The effect of anterior sphincteroplasty on fecal incontinence does not seem to deteriorate over time. A consensus Wexner cutoff is necessary to compare data and interventions.