Clinical, physiological, and radiological study of a new purpose-designed artificial bowel sphincter

Abstract

Background: Studies of the use of artificial urinary sphincters for faecal incontinence have led to refinement and adaptation of such sphincters to the anatomy of the anal region. We aimed to test this new device.

Methods: Six women, median age 53 (range 32-58) years, who were unsuitable for sphincter repair, had an artificial bowel sphincter implanted as a one-stage procedure without colostomy cover. Clinical assessment, physiological testing, and endosonography were done before and after the operation. Plain radiography, three-dimensional endosonography, and magnetic-resonance imaging were done after the operation, to define its anatomical location.

Results: Median follow-up was 10 (range 5-13) months and the device was functional in five patients. In one patient, the device was removed after ulceration through the skin. Of the patients with intact devices, Wexner incontinence scores improved from a median of 19 (18-20) of 20 before the operation, to 3 (0-6) of 20 after the operation. Median anal pressure at rest significantly increased from 60 (range 30-80) cm H2O to 110 (100-120) cm H2O. Functional anal-canal length varied after the operation from 3.3 cm to 3.8 cm. There was no significant change in the maximum tolerated volume of the rectum (140 [80-230] vs 100 [75-250] mL), or rectal compliance (2.9 [2.8-6.0] cm H2O/mL vs 3.5 [2.3-7.3] cm H2O/mL). All the imaging techniques accurately located the implant relative to the anal canal and pelvic floor in each patient.

Interpretation: The new artificial bowel sphincter provided a good functional result in five of the six patients, the surgical procedure was straightforward, and the maximum resting anal pressure rose without affecting rectal function. The ease of visualisation of such implants in situ should aid simple management of complications, should they arise.