Another study compared the effectiveness of artificial sphincter with dynamic graciloplasty (144). Two surgeons each performed four consecutive operations with each technique to minimize the learning curve of a new operation. Each started with a different procedure to avoid discrepancies in the time of follow-up. This prospective cohort study involved eight patients in each group who had similar demographic variables. Length of follow-up was 44 months in the artificial sphincter group and 39 months in the dynamic graciloplasty group. Early postoperative complications were similar in each group at 50%, as were late complications, with both groups reporting a high reoperation rate of 63%. There were six (75%) late complications in the artificial sphincter group, of which three (38%) were nonreversible and required explantation. Postoperative continence scores were significantly lower with the artificial sphincter than with graciloplasty. The authors conclude that artificial sphincter has better efficacy and similar morbidity compared with dynamic graciloplasty. The rate of late complications for the artificial sphincter exceeded that reported in the literature, which may indicate poor long-term durability. Postoperative continence scores reﬂect those reported for artificial sphincter but are far worse than those for dynamic graciloplasty. The authors feel that the learning curve with the artificial sphincter is less important than that with graciloplasty.
Sacral neuromodulation (InterStim®, Medtronic, Minneapolis, Minnesota) was approved by the FDA for treatment of urinary urge incontinence in 1997 and for nonobstructive urinary retention and urgency in 1999. It has been employed experimentally for the treatment of fecal incontinence and is currently undergoing FDA approval for this intervention. In Europe, it was approved for treatment of both urinary and fecal incontinence in 1994. The exact mechanism of action has not been fully elucidated. The goal of sacral nerve stimulation is to recruit residual function of the continence mechanism through electrical stimulation of its peripheral nerve supply. Initially, indications were confined to patients with deficient EAS and levator ani function without gross morphologic defects and intact neuromuscular connections. More recently, the acceptable indications have expanded to include deficiency of the IAS, limited structural defects, and functional deficits of the internal and external anal sphincter.
The device is instilled exactly the same way as for treatment of urinary incontinence. Current application is performed as a two-stage outpatient surgical procedure. The first stage involves instillation of the electrodes. The electrode is placed through the S2-4 foramen using minimally invasive surgical technique. During the test phase, multiple electrodes can be employed either bilaterally or at different levels to determine the site with the best response. Proper location is confirmed intraoperatively using ﬂuoroscopy as well as visualization of an appropriate pelvic ﬂoor muscle response (bellows) with minimal plantar ﬂexion of the first and second toes, which usually corresponds to S3 stimulation. An interval testing phase utilizes an external pulse generator that typically lasts 1 to 2 weeks. Those with a good response (decrease in fecal incontinence episodes of at least 50% documented by bowel-habit diary) will proceed to the second stage, implantation of the permanent pulse generator (IPG). Typically only one electrode is left in place at the end of the second stage. Once the permanent pulse generator is implanted, all adjustments are made using telemetry. The patient has a basic remote control that enables her to turn the device on or off and adjust the amplitude of the stimulation.