Prognostic Factors Associated with Poor Outcome of Biofeedback Therapy for Constipated Patients with Pelvic Outlet Obstruction

Kim, Sung Jin; Hwang, Yong Hee; Jung, Yong Hwan

Abstract

PURPOSE: The aim of this study was to identify the prognostic factors associated with poor outcome of biofeedback therapy.
METHODS
One hundred thirty-seven (137) constipated patients with pelvic outlet obstruction (median age 49 years) had more than one biofeedback session after defecography. Follow-up data (mean follow-up: 14 months; range: 2~37 months) were obtained in 114 patients. Any differences in demographics, clinical symptoms, and parameters of an anorectal physiological study were evaluated between the success group and the failure group.
RESULTS
At follow-up, 80 (70 percent) patients felt improvement in symptoms, but 34 (30 percent) patients did not. Pre-biofeedback presence of symptoms of difficult defecation predict poor outcome (88 vs. 69 percent for failure vs. success, P<0.05). The positive and the negative predictive values of difficult defecation for poor outcome were 35 percent and 86 percent, respectively. A negative mean pressure change on pre-biofeedback anal manometry was related to a poor outcome (65 vs. 26 percent for failure vs. success, P<0.001). The positive and the negative predictive values of negative mean pressure change for poor outcome were 51 percent and 83 percent, respectively. A negative electrical current change on pre-biofeedback anal electromyography was related to a poor outcome (23 vs. 9 percent for failure vs. success, P<0.05). The positive and the negative predictive values of negative electrical-current change for poor outcome were 53 percent and 74 percent, respectively.
CONCLUSIONS
Difficult defecation, negative mean pressure change in pre-biofeedback anal manometry, and negative electrical current change in pre-biofeedback anal electromyography were predictors associated with poor outcome of biofeedback therapy for constipated patients with pelvic outlet obstruction.