Prospective and retrospective data collection to optimize the use of multimodal intraoperative neuromonitoring

Abstract

Intraoperative neuromonitoring (IONM) is considered to increase safety in maximal resection of neurologic tumors. Center-specific warning criteria for IONM parameter changes associated with postoperative neurologic deterioration need to be established. A retrospective study determined the rate, type and severity of irreversible postoperative deterioration in past IONM-assisted neurosurgeries. A prospective observational pilot study examined whether IONM parameter changes can be correlated with postoperative deterioration. 13 of 93 (peri-)rolandic brain lesion, 20 of 78 CPA lesion, and 8 of 67 spine lesion cases had irreversible postoperative deterioration. Reoperation, male sex and schwannomas, and intramedullary location were significantly correlated with deterioration in brain, CPA and spine surgery respectively. No significant correlations were found between IONM parameter changes and postoperative deterioration. IONM does not exclude the risk of irreversible postoperative deterioration in (peri-)rolandic brain, CPA and spine surgery. However, deterioration does not by definition mean complete contralateral hemiparesis, facial nerve palsy or paraparesis. The lack of significant correlations is due to small sample sizes, heterogenous patient groups and limited variability. However, the postoperative clinical scores show a good outcome in treatment naive patients without preoperative deficits. Insights from this study will be used in a large-scale prospective study to obtain sound electrophysiological-clinical correlations.