Investigation of fecal incontinence with endoanal ultrasound

PURPOSE: This study was undertaken to audit the results of endoanal ultrasound in patients with fecal incontinence. METHODS: Endoanal ultrasound was used to investigate 53 patients with fecal incontinence. Data for endoanal ultrasound were collected prospectively. Results were compared with clinical and obstetric history, obtained retrospectively from case notes, and were compared with manometric and operative findings. RESULTS: Sphincter abnormalities were identified in 42 of 53 patients. A total of 28 anterior defects were thought to be obstetric in origin. Fourteen other defects were secondary to anal pathology or surgery. Patients with anterior external sphincter defects either had complete defects (4 patients; mean age, 31 years) or proximal defects (24 patients; mean age, 55 years). For patients with a proximal defect, 38 percent gave a history of obstetric tear, episiotomy, or forceps delivery, and the rest declared having had an apparently normal delivery. Only 50 percent had a sphincter weakness that was evident on clinical examination. Of those studied with manometry, only 21 percent had low squeeze pressures consistent with an external sphincter defect. CONCLUSIONS: Sphincter defects seen on ultrasound may not have a history of obstetric trauma or abnormal clinical and manometric findings. Endoanal ultrasound is recommended in all patients with fecal incontinence to detect occult sphincter defects.