Intraoperative Neurophysiological Monitoring (Motor and Somatosensory Evoked Potentials) in Dorsal Root Entry Zone Lesioning for Brachial Plexus Avulsion Pain.

AIMS

To address the feasibility and importance of intraoperative neurophysiological monitoring (IONM) in dorsal root entry zone (DREZ) lesioning for brachial plexus avulsion pain.

METHODS

Muscle motor evoked potential (mMEP) and somatosensory evoked potential (SSEP) were applied during DREZ lesioning for brachial plexus avulsion pain.

RESULTS

IONM of mMEPs and SSEPs was feasible for monitoring of the spinal cord during DREZ lesioning. With the exception of 3 unrecordable mMEPs in ipsilateral arms, mMEPs were preserved and referenced to look for changes according to lesioning in 6 upper extremities (66.6%) and 8 lower extremities. All 3 patients with >50% reduction in baseline mMEP amplitude after lesioning in either the ipsilateral upper or lower extremities showed postoperative ataxia and weakness of the lower extremities (100%). Only 2 out of 9 patients (22.2%) with brachial plexus avulsion pain had discernible baseline SSEPs in the ipsilateral upper extremities. One of 2 patients with discernible SSEPs in the upper extremities showed significant SSEP events during the DREZ lesioning and experienced postoperative ataxia and weakness in the legs despite the absence of a SSEP event in the lower extremities.

CONCLUSION

Significant events on IONM were common during DREZ lesioning for brachial plexus avulsion pain and were closely related to the occurrence of postoperative neurological deficits.