Neuromodulation: urodynamic effects of sacral (S3) spinal nerve stimulation in patients with detrusor instability or detrusor hyperflexia.

The aim of this study was to determine the urodynamic effects of sacral (S3) nerve stimulation in patients with urge incontinence due to detrusor overactivity which has been refractory to conservative treatment. A total of 24 patients with idiopathic detrusor instability and five with neurogenic hyperreflexia were studied urodynamically before and 6 months after a permanent S3 foramen electrode implant. The urodynamic studies at follow-up were done with the stimulus on. Clinically, the average voiding frequency, the number of leakage episodes and pad use per 24 h decreased significantly. Improvement in several urodynamic parameters was noted. In the idiopathic as well as in the neurogenic group, the correlation between symptomatic and urodynamic improvement was incomplete. Neuromodulation leads to improvement of several urodynamic parameters in patients with urge incontinence due to detrusor overactivity which has been refractory to conservative treatment and appears to be a valuable treatment option in these patients.