Endoanal Ultrasound Compared to Anorectal Manometry for the Evaluation of Fecal Incontinence: A Study of the Effect These Tests Have on Clinical Outcome

Abstract

Tests for evaluating incontinence include endoanal ultrasound (EUS) and anorectal manometry. We hypothesized that EUS would be superior to anorectal manometry in identifying the subset of patients with surgically correctable sphincter defects leading to an improvement in clinical outcome in these patients. The purpose of this study was to compare these 2 techniques to determine which is more predictive of outcome for fecal incontinence. Thirty-five unselected patients with fecal incontinence were prospectively studied with EUS and anorectal manometry to evaluate the internal anal sphincter (IAS) and external anal sphincter (EAS). EUS was performed with Olympus GFUM20 echoendoscope and a hypoechoic defect in the EAS or IAS was considered a positive test. Anorectal manometry was performed with a standard water-perfused catheter system. A peak voluntary squeeze pressure of < 60 mm Hg in women and 120 mm Hg in men was considered a positive test. All patients were administered the Cleveland Clinic Continence Grading Scale at baseline and at follow-up. Improvement in fecal control was defined as a 25% or greater decrease in continence score. EUS versus manometry were compared with subsequent surgical treatment and outcome. P-values were calculated using Fisher's exact test. Patients (n = 32; 31 females) were followed for a mean 25 months (range 13–46). Sixteen patients had improved symptoms (50%). There was no correlation between EUS or anorectal manometry sphincter findings and outcome. Seven of 14 (50%) patients who subsequently underwent surgery versus 9 of 18 (50%) without surgery improved (P = .578). In long-term follow-up, approximately half of patients improve regardless of the results of EUS or anorectal manometry, or whether surgery is performed.