Abnormal Balloon Expulsion Test in Patients with Fecal Incontinence

Background and Aims: Functional defecatory dysfunction is attributed to the pathophysiology of fecal incontinence (FI) in some patients. We hypothesized that patients with FI and abnormal balloon expulsion test (BET) have distinct manometric characteristics as compared to the patients with FI and normal BET. We aimed to compare the anorectal pressure profile in patients with FI, with or without abnormal BET and to identify risk factors associated with abnormal BET in FI. Methods: We performed a retrospective review of 77 consecutive patients with ROME IV FI. Wilcoxon rank sum test, t-test, and Fisher exact tests were performed for comparison. Multivariable logistic regression was performed to identify factors associated with abnormal BET. Results: Thirty-two percent of patients had abnormal BET. Demographics and surgical history and clinical symptoms, except for sensation of incomplete evacuation (p=0.02) and abdominal pain (p=0.03), were comparable in both groups. Anorectal pressure profile except for the median rectal propulsive pressures were similar between groups. Rectal propulsive pressures at simulated defecation were significantly lower in patients with abnormal BET (p=0.02). Mean sensory threshold for first sensation was also significantly higher in patients who had abnormal BET (p=0.03). Rectal propulsive pressures (OR: 1.03, 95% CI: 1.00-1.06, p=0.032) and rectal sensory threshold for first sensation (OR:0.94, 95% CI: 0.90-0.99, p=0.02) were able to predict abnormal BET independently. Conclusions: In patients with FI and similar clinical and anal pressure profile, rectal sensory threshold and rectal propulsive pressures at simulated defecation can determine normal BET.