Outcome after implantation of a novel prosthetic anal sphincter in humans

Background: A novel prosthetic anal sphincter (PAS) has been developed that aims to occlude by flattening and angulating the bowel, reproducing the action of the puborectalis muscle. The safety of the PAS has been confirmed in biomechanical, in vitro and long-term animal survival studies. The Medical Devices Agency approved implantation in 12 patients. Methods: The PAS was placed in the pelvis around the anorectal junction via a transabdominal approach in 12 patients with severe faecal incontinence. The device was activated 6 weeks after surgery. Fibreoptic examination of the mucosa below the device was undertaken at various intervals during review. Results: At a median follow-up of 59 (range 30-72) months nine of the 12 patients had a functioning PAS. There were no device-related infective complications after the initial operation but one patient developed pseudomembranous colitis and had the device removed. The PAS was effective in restoring continence in ten of 11 patients. Median (range) Cleveland Clinic continence scores improved from 16 (7-20) before to 3 (0-7) after surgery. In two patients the PAS was eventually removed owing to infection after revisional surgery. There was no clinical or histological evidence of gastrointestinal mucosal ischaemia. Conclusion: The PAS was effective in restoring continence. There was no device-related infection after the initial operation, no device erosion and no clinical or histological evidence of gastrointestinal ischaemia.