Continuous intraoperative monitoring of autonomic nerves during low anterior rectal resection: an innovative approach for observation of functional nerve integrity in pelvic surgery.

PURPOSE: The aim of this study was to develop a methodological setup for continuous intraoperative neuromonitoring with intent to improve nerve-sparing pelvic surgery.

METHODS

Fourteen pigs underwent low anterior rectal resection. Continuous stimulation of pelvic autonomic nerves was carried out with a newly developed tripolar surface electrode during lateral, anterolateral, and anterior mesorectal dissection. Neuromonitoring was performed under electromyography of the autonomic innervated internal anal sphincter.

RESULTS

Continuous neuromonitoring resulted in significantly increased electromyographic amplitudes of the internal anal sphincter, confirming intact innervation throughout the whole dissection in each animal (median 0.9 μV, interquartile range 0.5; 1.5 vs. median 3.4 μV, interquartile range 2.1; 4.7) (p < 0.001). The median dissection time in each animal was 10 min within a median number of ten (range 8-13) tripolar electric stimulations.

CONCLUSION

The present study is the first to demonstrate that continuous intraoperative monitoring of pelvic autonomic nerves during low anterior rectal resection is feasible.