Complications and troubleshooting of sacral neuromodulation therapy.

As evident from the authors' series, the complications of sacral neuromodulation have changed with the introduction of the tined lead and the placement of the generator over the back. In the earlier series, most complications were related to pain at the generator site, which was rare in the authors' series. The posterior location of the generator seems to be better tolerated than the anterior location, which could explain the rare need for revisions for pain at the generator site. Lead migration was observed in 8.4% of the original sacral neuromodulation study group series. This was seen rarely in the authors' series in either stage-one or stage-two revisions. As part of the routine work-up of patients who present with decreased function after a successful period response in stage two, the authors obtain a lateral radiograph of the sacrum; the authors have made the diagnosis of lead migration rarely (1/130; 0.6%). Spinelli and colleagues reported on the use of the tined lead in 15 patients, and observed no lead migration during either the screening period (average 38.8 days) or during follow-up of IPG implantation cases (average 11 months). The total infection rate in the whole series was 18/180 (10%), which was slightly higher than that reported by the sacral neuromodulation study group (6.1%). Revision rates for stage one and stage two were 12.2% and 20%, respectively. The revision rate in the original study group was 33.3%. Thus, with advancing technology, new problems may arise, but the implanting physician should be aware of the ways to evaluate and manage these complications and appropriately troubleshoot patients with suboptimal responses.