Pudendal nerve stimulation may be alternative to sacralneuromodulation

Stimulation of the pudendal nerve may be an alternative to sacral neurostimulation (SNS) in the treatment of urinary voiding dysfunction. Two studies presented yesterday indicate that pudendal neurostimulation (PNS) is effective in patients who do not respond to SNS.

"Neuromodulation has been a major advance in the management of voiding dysfunction," said Kenneth Peters, MD, of William Beaumont Hospital, Royal Oak, MI. "But not all patients respond to sacral nerve therapy."

The sacral nerve offers a single fiber, S3, linked to bladder function. The pudendal nerve, while more difficult to reach, provides stimulation through S2, S3, and S4. PNS can produce significant improvement in patients who had failed SNS, Dr. Peters reported.

In a 7-day randomized, blinded, crossover trial, 10 patients had a second lead placed at the pudendal nerve. Eight of the 10 responded and were implanted. Six patients chose PNS and two opted for SNS. The PNS patients reported a 63% improvement in symptoms versus a 40% improvement for SNS.

In a second trial, 19 of 22 patients responded to 15 minutes of PNS based on a 50% increase in first urge to void, volume until uninhibited bladder contraction, or maximum cystometric capacity. The 19 were give an implantable bion microstimulator (Advanced Bionics Corp., Sylmar, CA) that is currently in multicenter trials.

"Pudendal stimulation will be a new avenue to treat patients with voiding dysfunction," Dr. Peters said. "At least in the short term, I would like this to be an alternative to sacral stimulation."