Faecal incontinence is a socially embarrassing and physically disabling condition. It may be defined as the uncontrolled loss of faeces (liquid or solid) from the bowel. It may occur passively (without the person affected being aware of passing faeces) or be preceded by urgency ‐ a sense of an urgent need to defaecate. Faecal incontinence may result from damage to the anal sphincter mechanism (either from direct trauma or damage to its nerve supply), idiopathic degeneration of the sphincter, spinal injury or other neurological causes.

Those affected usually resort to containment using absorbent pads or anal plugs but these are often unsatisfactory. Clinical treatment is conservative in the first instance, including dietary advice, antidiarrhoeal medication and physical and behavioural therapy, for example pelvic floor muscle training and biofeedback (Cheetham 2001; Norton 2000; Norton 2003). A proportion of patients will remain resistant to these forms of treatment. With up to 10% of the adult population being affected by some degree of faecal incontinence a considerable number of people potentially require further treatment (Drossman 1993; Giebel 1998; Nelson 1998).

Surgical intervention has been the next step in the management of these patients. For external anal sphincter defects, overlapping sphincter repair may be undertaken. Early results show good symptomatic relief, but tend to deteriorate with time (Malouf 2000). Dynamic graciloplasty and artificial bowel sphincter implants may be attempted to improve continence, but require major surgery and have high morbidity and failure rates (Baeten 2000; Lehur 1998). Permanent stoma (colostomy or ileostomy) is another surgical option.

For people who do not respond to conservative treatments, sacral nerve stimulation (SNS) is a minimally invasive technique that should avoid the risks and morbidity associated with other types of surgery but might carry other risks. It allows modulation of the nerves and muscles of the pelvic floor and hindgut with potential beneficial effects, although the mechanism of its action is unclear.

SNS involves applying a low amplitude electrical current to a sacral nerve via an electrode placed through its corresponding sacral foramen. SNS has the advantage that it is possible to test each patient, over a two to three week period, with a percutaneous electrode attached to an external stimulator. If a significant benefit is achieved, implantation of the definitive implanted pulse generator (IPG) can then be carried out. Furthermore, the device can be removed if necessary, for example if complications occur. SNS using low amplitude electrical current for the treatment of faecal incontinence is a recent, innovative technique and a systematic review is needed to summarise the available evidence on its effects.