Purpose of Study: To observe the efficiency of the combined motor-somatosensory monitoring and somatosensory-alone monitoring to identify the intra-operative neurologic changes.

Methods and Results: We retrospectively assessed 123 cases in our centre, who had complete neurophysiological report while undergoing corrective spinal deformity surgery with spinal monitoring, from 2004 to 2008. Combined motor-somatosensory, somatosensory-alone and motor-alone monitoring were applied in sixty five, fifty and eight operations, respectively. We also looked at the factors that could potentially affect the neuro-physiologic monitoring, such as preoperative neurological status, anaesthetic method, blood loss, competency level of the monitoring team and the reaction of the surgical team to a significant monitoring event. In total, there were only two cases of true positive event, defined as a significant intraoperative event and postoperative neurological deficit. Both of these cases had combined monitoring during their procedures. No case of false negative was observed. There were also five cases with a significant intraoperative event without post operative neurologic sequel (false positive). Four of these had combined monitoring, with complete normal sensory monitoring and abnormal motor monitoring, which prompted the operating team to the appropriate action.

Conclusion: Based on this observation, it is felt that the combined monitoring during spinal deformity correction procedures is superior to the sensory-alone monitoring for identifying the impending neurologic deficits. This is in accordance with the previous reports and recommendations.