Neosphincters in the management of faecal incontinence

Surgical treatment of end-stage faecal incontinence has its origin in the early 1950s. Interest has been revived as a result of technical advances achieved in the recent past. The purpose of this article is to review the principles that underlie the use of skeletal muscle transposition around the anal canal and of electrical stimulation in the treatment of incontinence, and to explore new methods of treatment of this condition.

A literature search was performed using Pubmed and Medline, employing keywords related to treatment of faecal incontinence by neosphincter reconstruction. Basic science and clinical aspects of neosphincter reconstruction were gathered from relevant texts, original articles and recently published abstracts.

The electrically stimulated gracilis neoanal sphincter seems to be the popular choice of biological neosphincter. It is more likely to produce higher resting anal canal pressures than the unstimulated neosphincter, and hence improved continence. However, electrostimulator failure may result in explantation in a proportion of patients. Impairment of evacuation is a functional setback in approximately one-third of patients with the gracilis neosphincter. Overall, improvement of continence may be expected in up to 90 per cent of patients according to some reports. By contrast, experience with the artificial neosphincter, which is less expensive, has been limited to a few tertiary centres across the world. Reported continence of stool is 100 per cent, and that of gas and stool 50 per cent, following implantation of the artificial sphincter. Both of the above operations have been associated with implant-related infection and impaired evacuation.

Neoanal sphincter operations are technically demanding, require a considerable learning experience and should be confined to specialist colorectal centres. Patients are likely to benefit from a plan that incorporates preoperative counselling and a selective approach.