Simultaneous bilateral obturator nerve stimulation during transurethral electrovaporization of the prostate.

Transurethral vaporization of the prostate is a new method of electrosurgery used for treating benign prostatic hypertrophy. We observed simultaneous obturator nerve stimulation during spinal anesthesia while the middle lobe of the prostate was being resected. A discussion of why electrovaporization is different from traditional electrocautery devices is presented. Due to the increased power required during electrovaporization, and the arcing at the electrode, a large amount of demodulated, low-frequency current is produced that can stimulate the obturator nerve. This can occur even if the electrode is not close to the lateral bladder wall. The solution to the problem of obturator nerve stimulation, including bilateral obturator nerve blocks using a lower power setting during resection and converting from a regional to general anesthetic with neuromuscular blockade, is discussed.