[Peripheral nerve evaluation:indications, technique and results]

Sacral nerve neuromodulation is a new treatment modality for patients with chronic voiding dysfunction (CVD). The aim of this treatment is to restore the disbalanced micturition reflexes by electrical stimulation ot the sacral roots. Peripheral Nerve Evaluation (PNE) is the first step needed to determine wether sacral nerve stimulation for the control of lower urinary tract dysfunction is appropriate for a given patient, yielding accurate information about the location, integrity and function of sacral nerves, and motor and sensorial responses to electrical stimulation.

43 PNE in 28 patients (13 man and 15 women) were performed between january 2000 and november 2001 (mean age 56.3 years old, 22-76). Every patient have been diagnosed of CVD: 13 Urinary Urge Incontinence (UUI). 5 Urgency-Frequency Syndrome (UFS), 7 Dysfunctional Voiding (DV) and 3 Mixed Syndromes (1 patient UFS + DV and two patients with UUI + DV).

Every acute stimulation showed positive sensory and motor responses. There was premature lead migration in 8 PNE (18.6%), preventing an appropriate evaluation of the temporal stimulation. 35 PNE were evaluated after a 6.5 days period (3-15) of electrical stimulation. There were no significative complications, and PNE was well tolerated. Good clinical results (> 50% reduction in symptoms) were observed in 7/13 patients with UUI (53.8%), 2/5 patients with UFS (40%), 1/7 patients with DV (14.2%) and 1/3 patients with mixed syndromes (UUI + DV) (33.3%). 11 of 28 patients with CVD (39.2%) have been selected as candidates for permanent implantation.

Actually, PNE is the first step needed to determine wether sacral nerve stimulation for the control of lower urinary tract dysfunction is appropriate for a given patient. With PNE we can select properly adequate candidates for permanent implantation. It is an easy and well tolerated technique, and can be performed in any medical center in an outpatient basis.