[New monitoring method for the pudental nerve during surgery: cases of intraoperative monitoring for lumbo-sacral lipomeningocele].

We carried out intraoperative monitoring of the pudental nerve while separating vertebral spinal tumors from the spinal cord in five patients, including four infants. Although monitoring using a manometer or needle electrodes has been reported, monitoring done with disk electrodes to ascertain the compound muscle action potential (CMAP) of the external sphincter muscle has not been yet attempted. Prior to the surgical procedure, we locate a point suitable for CAMP recording of the muscle. In our recent study, we determined that maximum action potentials were recorded in the part with the greatest depth from the individual anal verge. Therefore, the depth of the anal canal was preoperatively measured for the manometry method, and sphincter electrodes currently on the market were refigured to suit the infant's anal canal. After the two procedures described above, we were able to preserve the pudental nerves intraoperatively. The postoperative neurological findings of all five patients were unchanged. We introduce here this new method of intraoperative monitoring for preserving the pudental nerve.