The Effect of Sacral Neuromodulation on Pudendal Nerve Function and Female Sexual Function

Aims: To quantify changes in pudendal nerve function with sacral neuromodulation (SNM). To understand the relationship of pudendal nerve function to SNM treatment response for overactive bladder. To assess the relationship between female sexual function and pudendal nerve function after SNM.

Methods: Women undergoing SNM between January 2010 and May 2011 were enrolled. Baseline pudendal nerve terminal motor latencies (PNTML) were measured bilaterally. Subjects underwent peripheral nerve evaluation (PNE) prior to SNM therapy. PNTML was measured at 1 and 6 weeks after sacral neuromodulator implant. Women who did not undergo permanent implantation were reassessed at the end of the 1-week PNE testing phase. Pelvic floor and sexual function questionnaires were administered at baseline and follow-up to assess pelvic floor and sexual function.

Results: Of 34 women enrolled, 31 were evaluated. Mean age was 67.4 ± 14.2 years with 29/34 (85.3%) treated for refractory overactive bladder. Thirty of 31 (96.7%) went on to a permanent implant. PNE success rate was 73.5% (25/33). Mean PNTML changed from 2.74 ± 0.52 msec at baseline to 2.57 ± 0.50 msec at 6 weeks postop (P = 0.198). Baseline amplitude remained stable at 1 and 6 weeks. At 6 weeks PISQ-12 scores showed improved sexual function (P = 0.034) and PFDI-20 and PFIQ-7 scores showed improved pelvic floor, colorectal and urinary symptoms (P < 0.05).

Conclusions: Women with refractory overactive bladder and non-obstructive urinary retention have abnormal pudendal nerve function, which showed a non-significant trend toward improvement after SNM. Sexually active women undergoing sacral neuromodulation experienced improvement in sexual function. Quality of life improved due to improvement in urinary and colorectal function.