Efficacy of Sacral Nerve Stimulation for Fecal Incontinence in Patients with Anal Sphincter Defects

PURPOSE: Sacral nerve stimulation has traditionally been used to treat patients with fecal incontinence with intact anal sphincters. This rationale has been challenged, but it remains unknown if its efficacy is related to the extent of the sphincter injury. METHODS: This was a prospective study of 15 patients with sphincter defects (9 combined, 2 external only, and 4 internal only) undergoing sacral nerve stimulation for fecal incontinence. Endoanal ultrasound scans were reviewed and defects scored (0-16) with use of a system published by two independent observers. These were correlated with the following outcomes: 1) reduction in fecal incontinence episodes, 2) reduction in soiling, 3) improvement in Cleveland Clinic scores, and 4) improvement in ability to defer defecation. All patients were studied after temporary stimulation and again at three to six months after permanent implantation. RESULTS: Thirteen patients (87%) progressed to permanent stimulation. Median fecal incontinence episodes per two weeks decreased from 15 (range, 1-53) to 3 (range, 0-16; P = 0.01). Median soiling episodes were reduced from 10 (range, 1-14) to 6 (range, 0-14; P = 0.009). Median Cleveland Clinic scores decreased from 12 (range, 9-18) to 9 (range, 4-14; P = 0.0005). The ability to defer defecation was improved significantly (P = 0.05). There were no relationships between sphincter defect scores and outcome measures after sacral nerve stimulation (r(2) = 0.001-0.10; P = 0.28-0.94). CONCLUSION: Sacral nerve stimulation is an effective treatment in patients with fecal incontinence who have anal sphincter defects, and outcome is not associated with severity of sphincter disruption.