Purpose: The aims of this review are 1) to critically evaluate the literature on the efficacy of biofeedback treatment for fecal incontinence, 2) to compare different types of biofeedback, and 3) to identify patient characteristics which predict a successful outcome.
Methods: The MEDLINE database was searched for articles published between 1973 and 1999 which included the terms "biofeedback" and "fecal incontinence." Pediatric and adult articles in any language were screened. Inclusion for review required that the study be prospective, have five or more subjects, and have a description of the treatment protocol.
Results: Thirty-five studies were reviewed. Only six studies used a parallel treatment design and just three of those randomized subjects to treatment groups. A meta-analysis (weighted by subjects) was performed to compare the results of two treatment protocols that dominate the literature. The mean success rate of studies using Coordination training (i.e., coordinating pelvic floor muscle contraction with the sensation of rectal filling) was 67 percent, while the mean success rate for studies using Strength training (i.e., pelvic floor muscle contraction) was 70 percent. Furthermore, the mean success rate for those Strength training studies using electromyographic biofeedback was 74 percent, while the mean success rate for studies using anal canal pressure biofeedback Strength training was 64 percent. However, these conclusions are limited by the absence of clearly identified criteria for determining success. There are also inconsistencies in the literature regarding the patient selection criteria, severity and cause of symptoms, amount of treatment, as well as the type of biofeedback protocols and instrumentation used. Finally, no patient characteristics were identified that would assist in predicting successful outcome.
Conclusion: Although most studies report positive results using biofeedback to treat fecal incontinence, quality research is lacking. Recommendations are made for future investigations to 1) improve experimental design, 2) include long term follow-up data, and 3) to use an adequate sample size that allows for meaningful analysis.