[Clinical Results of PNE Tests in 70 Patients with Different Bladder Dysfunctions]

Prior to implantation of a sacral neuromodulator we carried out PNE tests (peripheral nerve evaluation test) with bilateral test stimulation to establish which patients might profit from this kind of therapy. In contrast to the original unilateral technique used by Tanagho and Schmidt, we performed bilateral PNE test stimulation. Moreover, we analysed the diagnostic characteristics of those patients who had positive PNE test results and could thus receive a chronic sacral neuromodulator.

We performed bilateral PNE test stimulation in 70 patients (mean age: 53.6 yrs; 41 with retention symptoms and 29 with a hyperactive detrusor) over a minimum of 3 days. Retrospectively, we analysed the distribution of diagnostic characteristics (retention vs. overactive bladder and neurogenic vs. idiopathic) in the implant recipients.

All patients received bilateral PNE test stimulation, during which the stimulation amplitudes were adjusted individually for each side. 8 patients were treated with the original PNE-electrode (model 0 041 830 - 002, Medtronic Inc., USA) without success. Of the remaining 62 patients, who were treated with an improved electrode, the PNE test was successful in 32 cases (51.6 %). Twenty-seven of these patients suffered from a neurogenic bladder dysfunction, and, in 5 cases, the causes were idiopathic.

Bilateral PNE-test stimulation and the use of advanced PNE electrodes (model 3057, Medtronic Inc., USA) led to a positive PNE result in 51.6 % of the tested patients. Of these, the group with neurogenic bladder dysfunctions showed the highest response rate. Compared with the success rates in the multicenter study, we were able to increase the overall PNE response rate significantly. For this reason, we prefer a bilateral PNE-test with side-specific stimulation.