2 The condition, current treatments and procedure
2.1 Faecal incontinence is an inability to control bowel movements, resulting in the involuntary passage of faeces. The process of defaecation and its control is complex. Causes of incontinence include problems in the colon and rectum (including constipation and diarrhoea), problems with the sphincter muscles (such as damage caused by childbirth or surgery), or nerve damage (such as multiple sclerosis, stroke or spina bifida). Faecal incontinence can also be caused by loss of higher-level cerebral control in conditions such as dementia or severe learning disability.
2.2 NICE's guideline on faecal incontinence in adults states that there is no consensus on methods of classifying the symptoms and causes of faecal incontinence. It is most commonly classified according to symptom, character of the leakage, patient group or presumed primary underlying cause. For many people faecal incontinence is the result of a complex interplay of contributing factors, some of which may be relatively simple to reverse. Therefore, a detailed initial assessment and structured approach to management is needed, starting with addressing reversible factors and, only if this fails to restore continence, progressing to specialised management.
2.3 Initial management of faecal incontinence includes interventions related to diet, bowel habit, toilet access and medication. Specialised management options depend on the underlying cause and include pelvic floor muscle training, bowel retraining, specialist dietary assessment and management, biofeedback, electrical stimulation and rectal irrigation. The main surgical treatment is anal sphincter repair. Sacral nerve stimulation may be offered to people for whom sphincter surgery is not appropriate. If a trial of sacral nerve stimulation is unsuccessful, a neosphincter may be considered (stimulated graciloplasty or an artificial anal sphincter).
2.4 Self-expanding implant insertion into the intersphincteric space for faecal incontinence is done using local or general anaesthesia, with ultrasound guidance. About 6 to 10 small (2 mm) incisions are made in the perianal skin, equidistant to each other, about 2 cm from the anal margin. An introducer is inserted into each incision in turn, pushed through a short subcutaneous tunnel and into the intersphincteric space. The implant is deployed in the desired position within the intersphincteric space. This is repeated around the entire circumference of the internal anal sphincter. The incisions are sutured with resorbable material. Patients are advised to avoid any heavy physical activity for a few days after surgery. One type of implant is a solid polyacrylonitrile cylinder (non-biological) that becomes thicker, shorter and softer over 1 day to 2 days after implantation. The implants expand and press together, forming a ring that creates an artificial sphincter. The aim is to give the person more control over their ability to control defaecation.