Sacral neuromodulation for lower urinary tract dysfunction and impact on erectile function.

INTRODUCTION

The first sacral nerve stimulators were for urinary urgency incontinence, urgency-frequency, and nonobstructive urinary retention. Since then, observations have been made for benefits beyond voiding disorders.

AIM

To evaluate if sacral neuromodulation (SNM) using the InterStim system (Medtronic Inc., Minneapolis, MN, USA) improves erectile function.

METHODS

From January 1999 to January 2007, 54 males, mean age 42.8, underwent a permanent SNM for lower urinary tract symptoms (LUTS). Pre-SNM only subjects with concomitant erectile impairment according to the five-item version of the International Index of Erectile Function (IIEF-5), with normal blood sexual hormonal status, and responding to an intracavernous injection test 10 microg were enrolled in our study. Three months after permanent implantation, the IIEF-5 was completed again. Those who benefited significantly in erectile function completed the IIEF-5 semiannually. A final checkup was performed in July 2007.

MAIN OUTCOME MEASURES

A score of IIEF-5 equal to or higher than 25% compared to baseline indicated remarkable clinical enhancement.

RESULTS

Presurgery, two patients were excluded. Overall, 22 subjects (42.3%) showed erectile impairment (14 were neurogenic). In the first visit post-SNM, five retentionists of neurogenic origin and two with overactive bladder syndrome of idiopathic origin achieved noticeable erectile improvement. Their median IIEF-5 score shifted from 14.6 to 22.2, and 15.5 to 22.5, respectively. During follow-up, two neurogenics lost the benefits concerning voiding and erection and recovered them after a new implant in the contralateral sacral S3 root. In the final visit, the seven responders reached an IIEF-5 score of at least 22.

CONCLUSIONS

Our study showed a clinically important benefit of sexual function mainly for neurogenic retentionists. Future research should test SNM in a larger sample of subjects, exclusively with sexual dysfunctions, in order to better understand the mechanism of action of SNM on erectile function.