This is a retrospective study of 109 consecutive patients referred to the Neurophysiology Department from January, 2001 to December, 2005 for Somatosensory evoked potentials (SSEP's) during anterior cervical spine fusion (ADSF) surgery. The mean age of the patients was 51.83 (range: 22 - 79 years) with 61 males and 48 females. Most of the cases had degenerative spine disorders with 88 radiculopathic and 21 myelopathic patients and were mostly due to Hermated Nucleus Pulposus or Degenerative Disk Disease. Majority of the surgeries were 3-level instrumented fusions. There were 103 discectomies and 6 corpectomies with fusion.
Result allowed that the use of SSEP's during anterior cervical spine fusion surgery had a sensitivity and specificity rates of 36.8 percent and 73.3.6 percent, respectively. Positive and negative predictive values were 22.6 percent and 84.6 percent, respectively. There were 33 (30.3 percent) patients detected with abnormal recordings with 19 (17.4 percent) showed post-operative neurologic deficits. There were 7 true positives (6.4 percent) and 12 false negatives (11 percent). Most of the deviations in the latency and amplitude occurred during the decompression period followed by discectomy, then both graft insertion and instrumentation. With the above results, the authors of the study strongly conclude that use of SSEP's during ADSF was helpful in detecting events where a neurologic injury occurred. Moreover, the use of multi-modality neuromonitoring is recommended to determine injuries at the spinal cord and nerve root level.
To identify or detect specific events during anterior cervical spinal fusion surgery where an intra-operative neurologic injury has occurred using SSEP's, to determine whether or not an intra-operative neurologic injury was avoided as a result of the SSEP monitoring, to correlate intra-operative electrophysiologic changes with the development of new clinical neurologic deficits, and, to determine whether intra-operative monitoring of the spinal cord with SSEP's was helpful in identifying neurologic impairment or dysfunction.