Injectable silicone biomaterial for faecal incontinence due to internal anal sphincter dysfunction.

Background: A weak or disrupted internal anal sphincter can cause passive faecal incontinence. Conservative measures may help some patients but there is no simple surgical solution for those who fail conservative treatment. A successful technique using trans-sphincteric injection of a bulking agent to augment the internal anal sphincter was developed in a previous pilot study. Aim: To determine the clinical results and underlying physiological effects of biomaterial injection. Patients: Six patients (four males, median age 53 years (range 36–65)) with faecal incontinence to solid or liquid stool related to poor internal anal sphincter function, of varied aetiology, were recruited. Methods: Silicone based biomaterial injections were performed, under local anaesthesia, with antibiotic cover. Three injections were placed circumferentially, trans-sphincterically, entering away from the anal margin and injecting at or just above the dentate line. Anorectal physiological studies, endoanal ultrasound, a bowel symptom diary, a validated incontinence score, and quality of life questionnaires were completed before treatment and on completion of follow up. Results: At a median follow up of 18 months (range 15–19), five of six patients had marked symptom improvement. Faecal incontinence scores improved from a median of 14/24 (range 11–20) before to 8/24 (6–15) after injection. Short form-36 quality of life physical and social function scores improved from a median of 26/100 (5–33) to 79/100 (25–100) and from 10/100 (5–37) to 100/100 (50–100), respectively. There was a corresponding physiological increase in maximum anal resting and squeeze pressures. Ultrasound showed the Bioplastique to be retained in the correct position in the improved patients without migration. There were no complications. Conclusion: Trans-sphincteric injection of silicone biomaterial can provide a marked improvement in faecal incontinence related to a weak or disrupted internal anal sphincter. This is associated with improved sphincter function and quality of life.