Improving neuromodulation technique for refractory voiding dysfunctions: two-stage implant

Abstract

Objectives: Neuromodulation is a new technique that uses electrical stimulation of the sacral nerves for patients with refractory urinary urge/frequency or urge-incontinence, and some forms of urinary retention. The limiting factor for receiving an implant is often a failure of the percutaneous nerve evaluation (PNE) test. Present publications mention only about a 50% success score for PNE of all patients, although the micturition diaries and urodynamic parameters are similar. We wanted to investigate whether PNE results improved by using a permanent electrode as a PNE test. This would show that improvement of the PNE technique is feasible.

Methods: In 10 patients where the original PNE had failed to improve the micturition diary parameters more than 50%, a permanent electrode was implanted by operation. It was connected to an external stimulator. In those cases where the patients improved according to their micturition diary by more than 50% during a period of 4 days, the external stimulator was replaced by a permanent subcutaneous neurostimulator.

Results: Eight of the 10 patients had a good to very good result (60% to 90% improvement) during the testing period and received their implant 5 to 14 days after the first stage.

Conclusions: The good results of the two-stage implant technique we used indicate that the development of better PNE electrodes may lead to an improvement of the testing technique and better selection between nonresponders and technical failures.