Responses of anal constipation to biofeedback treatment

Objective. Biofeedback is considered an effective treatment for anal constipation, but a substantial proportion of patients fail to improve. Our aim was to identify the key predictors of outcome using a comprehensive standardized evaluation of anorectal function. Material and methods. We retrospectively analysed the clinical and physiological data of 148 patients consecutively treated for constipation due to functional outlet obstruction by biofeedback. Clinical evaluation was performed by means of a structured questionnaire. Anorectal evaluation included anal pressure, neural reflexes, defecatory dynamics, rectal compliance, rectal sensitivity and balloon expulsion test. Biofeedback treatment was performed using a manometric technique. The clinical response to biofeedback treatment was evaluated as good (improvement of constipation) or poor (no improvement or worsening). Results. Of the 148 patients included, 112 (86 F, 26 M; age range 8-67 years) were followed-up for between 1 and 44 months, and 66% had a good response to treatment. The response depended on the severity of the defecatory dysfunction. Thus, lack of anal relaxation during straining and inability to evacuate a 1 ml intrarectal balloon were inversely related to physiological variables related to therapeutic success. Among the 49 patients with absent anal relaxation, 51% had a good response to treatment (versus 78% in patients with partial relaxation; p < 0.01), and among the 29 patients with failed balloon expulsion, 48% responded to treatment (versus 74% in patients able to evacuate ≥ 1 ml intrarectal balloon; p < 0.05). Conclusions. Even in the presence of negative predictors, biofeedback is a valuable treatment option in a substantial proportion of constipated patients.