Faecal incontinence is caused by a variety of conditions that can affect either the anatomy or function of the anal sphincter. These conditions include perineal injury during childbirth, neurological or spinal disease/injury (for example, stroke, multiple sclerosis or spinal cord injury), congenital anorectal dysfunction, pelvic organ prolapse, colonic resection or anal surgery, or pelvic radiotherapy.
First-line treatment for faecal incontinence is usually conservative and includes dietary management and antidiarrhoeal medication. This may be followed by pelvic floor muscle training, biofeedback therapy and electrical stimulation. If conservative treatments fail, local surgery to repair the sphincter may be recommended. If local surgery proves inadequate, alternatives include sacral nerve stimulation, graciloplasty (creation of a new sphincter from other suitable muscles) or implantation of an artificial anal sphincter (anorectal or transabdominal). The most severe cases may require a permanent colostomy.
Artificial bowel sphincters are usually implanted into the perineum. However, complications (such as infections and erosion of the implant into surrounding tissue) are common at this site, often resulting in surgical revision or removal of the device. Transabdominal implantation aims to achieve a lower rate of complications. Usually with the patient under general anaesthesia, a lower mid-line incision is made to allow the inflatable sphincter cuff (consisting of an expander and a gel-filled pillow) to be placed at the anorectal junction and held in place by a strap. A subcutaneous pouch is then created for the control pump, usually in the right iliac fossa. A balloon reservoir is placed within the peritoneal cavity in the pelvis. The connecting tubes from the sphincter cuff and the balloon reservoir are connected to the control pump and the abdomen is closed.
When inflated, the cuff keeps the anal canal closed. To evacuate the bowel, the patient presses the control pump's button against the abdominal wall. This deflates the cuff and opens the sphincter by pumping fluid from the sphincter cuff into the balloon reservoir. On completion of defaecation, the patient closes the sphincter by pressing the button on the pump again. This opens the pump, allowing fluid to return to the cuff and producing angulation between the rectum and the anal canal.
Sections 2.3 and 2.4 describe efficacy and safety outcomes which were available in the published literature and which the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the overview.
A case series of 12 patients reported that 75% (9 out of 12) of patients had a functioning implant at a median follow-up of 59 months (range 30 to 72 months). Five of the 9 (56%) required surgical revision (4 to replace the pump and 1 because of strap disruption). In the same study, the median Cleveland Clinic Incontinence Score (in which the maximal faecal incontinence score is 20) improved from 16 (range 7 to 20) before the procedure to 3 (range 0 to 7) after the procedure in the 10 patients whose faecal incontinence could be assessed.
The Specialist Advisers stated that key efficacy outcomes include restoration of faecal continence, absence of mucus leakage and improved quality of life.
The case series of 12 patients reported that 25% (3 out of 12) of patients required removal of the device because of complications, including infection after revision surgery in 2 patients and pseudomembranous colitis during the perioperative period in the third patient.
The Specialist Advisers stated that theoretical adverse events include infection, migration of the device within the pelvis, disturbance of the blood supply to the bowel, and rectal injury caused by pressure from the artificial sphincter. One Adviser stated that surgical revision of this procedure is likely to be more difficult than surgical revision after perineal implantation.
The Committee noted that the technology was modified during the single small case series that reported on this procedure and that further development and modifications are likely to occur.