Aim of Study:
An urgency and frequency syndrome due to an overactive bladder can successfully be treated by afferent nerve stimulation of the S3 spinal regions. Aim of this study was to determine the efficacy of peripheral neuromodulation of the S3 region in patients with urgency-frequency syndrome due to an overactive bladder.

Patients and Methods:
15 patients (11 women and 4 men), suffering from urgency-frequency syndrome, as documented by a voiding chart were diagnosed with overactive bladder. Pelvic pain was assessed by an visual analogue scale (VAS). Full urodynamic work-up was performed before and after 12 peripheral stimulations with a 9V monopolar generator, the so-called Stoller Afferent Nerve Stimulator (SANS™) utilising a minimal invasive transcutaneous access to the posterior tibial nerves. Patients follow-up was for a mean (SD) 10.9 (4-15) months post treatment.

Results:
No complications were observed. Reduction in pain was achieved in all patients, with a decrease in VAS from a mean (SD) of 7.6 (5-10) to 3.1 (1-7) (p=0.00049). Seven patients (46.7%) had a complete response and were considered cured; three (20.0%) showed significant improvement; and five (33.3%) were classified as non-responders. Urodynamic evidence of bladder instability, evident in all patients prior to treatment, was eliminated in 76.9% of patients. In all patients, mean (SD) total bladder capacity increased significantly from a 197 (35-349) to 252 (78-384) ml (p=0.00795), mean (SD) volume at first bladder sensation from 95 (16-174) ml to 133 (32-214) ml (p=0.00166) and mean (SD) bladder volume at normal desire to void from 133 (27-217) ml to 188 (47-296) ml (p=0.00232). In the responding group, the mean (SD) total numbers of voids was reduced from 16.1 (9-24) times during the day and 4.4 (2-6) times during the night to 8.3 (6-10) and 1.4 (1-2) times (p=0.002539), respectively. In addition we observed a decrease in the number of protective pads from 4.9 to 1.6 per day.

Conclusions:
Peripheral neuromodulation of the S3 region can successfully treat patients suffering from urgency-frequency syndrome due to an overactive bladder. Morbidity of this treatment is negligible. Clinical results may be improved by proper patients selection since patients with severe anatomical deficiency, interstitial cystitis and neurological disorders seem to be unsuitable candidates for this technique.

Aknowledgment:
The SANS device was provided by UroSurge Inc. Iowa, USA and the study was approved by the local ethics committe ( No. EK 327/98).