Biofeedback is a well-known and effective treatment for patients with fecal evacuation disorder (FED). The main purpose of this study was to investigate the outcome and the effects of biofeedback therapy on physiological parameters as assessed by manometry in patients with FED. Data from 114 consecutive patients with FED who underwent biofeedback therapy in Sara Gastrointestinal clinic in Tehran, Iran during 2015-2018 were retrospectively reviewed and analyzed. All participants underwent a comprehensive evaluation of anorectal function that included anorectal manometry and a balloon expulsion test at the baseline and after biofeedback therapy. Maximum anal squeeze pressure and sustained anal squeeze pressure were improved up to 100% and 94.7% of normal values in the patients after biofeedback, respectively (P < 0.001). First rectal sensation, was significantly decreased (25 ± 18.5 vs. 15.5 ± 5.2) while the maximum tolerable volume was significantly increased (233.6 ± 89.7 vs. 182.4 ± 23.1) after biofeedback therapy (P < 0.001). Type I dyssynergia was the most common type, effecting 82 cases (71.9%) of our patients. Dyssynergia parameters were improved 50-80% in 34 (41.5%) and 10 (31.3%) type I and non-type I patients, respectively. Over 80% improvement of dyssynergia parameters occurred in 48 (58.5%) and 22 (68.8%) type I and non-type I patients, respectively. These differences were not statistically significant between the two groups (P = 0.3). In addition, the ability to reject the balloon was significantly better in post intervention measurements (P < 0.001). Biofeedback not only improves the symptoms in patients of FED but also reverses more than 80% the dyssynergic parameters of defecation. However, due to the general effectiveness of biofeedback treatment in different types of DD, there were no significant differences between their improvement scores.
Keywords: Anorectal manometry; Biofeedback; Chronic constipation; Defecation.