Case reportNeurophysiological monitoring of lumbar spinal nerve roots: A case report of postoperative deficit and literature review

- In rare cases postoperative neurological deficits may still happen despite intraoperative neurophysiological monitoring.
- This article focus on lumbar nerve root deficits, reporting lower extremity paralysis observed after spinal deformity correction surgery.
- Journal articles from the past 20 years reporting lumbar nerve root deficits associated with neurophysiological data were reviewed.
- A multimodality protocol combing electromyography and evoked potentials may increase the chance of successful nerve root monitoring.
- We would like to call for more cases reports of postoperative neurological deficits as they present difficult clinical cases.

IntroductionIntraoperative neurophysiological monitoring (IONM) has proven to help reduce the probability of postoperative neurological deficit for spinal deformity correctional surgeries. However, in rare cases new deficits may still happen. We report a surgical case in which the patient had postoperative paralysis. We would like to call for more case reports with postoperative neurological deficits as they present difficult clinical cases.Presentation of caseA 61-year-old male patient with severe thoracolumbar kyphoscoliosis underwent posterior spinal correction and fusion with segmental T10-L5 pedicle screws and rods instrumentation with IONM. The only intraoperative event was a pedicle breach at left L3 which was detected by triggered electromyography (EMG) testing, and the pedicle screw was repositioned. Left lower extremity paralysis was observed upon patient awakening. He received rehabilitation treatment and had limited recovery of muscle strength. Partial lumbar nerve root injury was likely the cause of the paralysis.DiscussionThis is a case with new lumbar nerve root deficit, with positive EMG signal change, but negative somatosensory evoked potential (SSEP) and motor evoked potential (MEP) findings. We discuss the different neurophysiological modalities for monitoring lumbar spinal nerve root function. We review journal articles from the past two decades which reported lumbar root deficits, and list neuromonitoring events during the surgeries.ConclusionMultimodality monitoring with spontaneous and electrically triggered EMG combined with SSEP and MEP may provide the best chance to detect lumbar nerve root injuries.