RADIOLOGICAL INVESTIGATIONS AND INTRAOPERATIVE EVOKED-POTENTIALS FOR THE DIAGNOSIS OF NERVE ROOT AVULSION - EVALUATION OF BOTH MODALITIES BY INTRADURAL ROOT INSPECTION

Fourteen patients with traumatic brachial plexus injuries underwent in tradural inspection of cervical nerve roots to evaluate radiological a nd intra-operative electrophysiological findings concerning cervical n erve root avulsion from the spinal cord. Four neurosurgeons of our dep artment assessed independently from each other both myelography and CT -myelography concerning intradural nerve root lesions. Each neurosurge on assessed a total of 26 cervical nerve roots. Two investigators asse ssed 6/26 and 2 investigators 7/26 nerve roots falsely concerning Vent ral or/and dorsal root lesions compared with the findings on intradura l inspection (23% and 27% false findings). There was a considerable va riance concerning the assessibility and findings among the 4 neurosurg eons. Reconstructive surgery was performed after a mean interval of 6. 5 months following trauma and 2 weeks following intradural inspection. After exposure of the brachial plexus and the cervical nerve roots in question via a ventral approach, 13 cervical nerve roots were stimula ted electrically close to the neuroforamen and cortical evoked potenti als (root-SEPs) were recorded from the contralateral postcentral regio n. All 5 roots with SEPs were intact (no root lesion) and all 8 roots without SEPs showed interrupted (ventral or/and dorsal) rootlets on in tradural inspection. Our results demonstrate that false radiological f indings concerning root lesions are possible. Intra-operative root-SEP s seem to be a useful aid for evaluation of cervical nerve root lesion s. However, more electrophysiological data are necessary to ascertain, if this modality is able to replace intradural inspection in unclear radiological cases in the future.