Intraoperative neuromonitoring of hypogastric plexus branches during surgery for rectal cancer - preliminary report

The aim of this study was to present our preliminary experience with intraoperative neuromonitoring during rectal resection.

We qualified 4 patients (2 women, 2 men; age 42 - 53 years) with rectal cancer for surgery with intraoperative neuromonitoring. In all patients, functional tests of the anorectal area were performed before surgery. Action potentials from the sphincter complex in response to nerve fiber stimulation were recorded with electrodes implanted before surgery. Moreover, we inserted a standard, 18FR Foley's urinary catheter to which a T-tube was connected to allow urine outflow and measurement of pressure changes in the bladder induced by detrusor contractions during stimulation.

Setting up neuromonitoring prolonged surgery time by 30 to 40 minutes, or even by 60 to 80 minutes in the case of the first two patients. Neuromonitoring itself took additional 20 to 30 minutes during surgery. In all patients, we stimulated branches of the inferior hypogastric plexus in their anatomical position during dissection. In three patients, we evoked responses both from the bladder and the sphincter in all planes of stimulation. In one patient, there was no response from the left side of the bladder, and in the same patient, we observed symptoms of neurogenic bladder.

Based on the available literature and our own experience, we state that monitoring of bladder pressure and electromyographic signals from rectal sphincters enables visualization and preservation of autonomic nervous system structures, both sympathetic and parasympathetic. Intraoperative signals seem to be correlated with clinical presentation and functional examinations after surgery. In order to objectify our results, it is necessary to perform functional examinations before and after surgery in a larger group of patients.