Long–Term Effectiveness of Sacral Nerve Stimulation for Refractory Urge Incontinence

Objectives:To evaluate the long–term efficacy of sacral nerve stimulation for refractory urinary urge incontinence. Study Design and Methods:Urge incontinent patients qualified for surgical implantation of a neurostimulator system after trial screening with percutaneous test stimulation. Surgical implantation of the InterStim System (Medtronic Inc., Minneapolis, Minn., USA) was performed in cases where a >50% reduction in incontinence symptoms was documented during the 3– to 7–day test stimulation period. The InterStim System consists of an implantable pulse generator, a transforamenally placed quadripolar lead, and an extension that connects these two devices for unilateral stimulation of the S3 or S4 sacral nerve. Efficacy for 96 implanted patients was based on urinary symptom changes as quantified in voiding diaries collected at baseline and annually after surgical implantation. Results:As compared to baseline, the group of 96 implanted patients demonstrated significant reductions in urge incontinent symptoms at an average of 30.8±14.8 (range 12–60) months with respect to the number of urge incontinent episodes per day, severity of leaking, and the number of absorbent pads/diapers replaced per day due to incontinence (all p<0.0001, respectively). Gender, pretreatment variables, and age were not found to be relevant factors that affected these results. 11 of the 96 patients underwent device explant due to lack of efficacy, pain or bowel dysfunction. These data were conservatively included in the efficacy results. No permanent injuries associated with the devices or therapy were reported. Conclusion:Sacral nerve stimulation is an effective treatment for refractory urge incontinence with sustained long–term benefit through an average of 30.8 months.