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Tumor Rapid Fire Abstract

Tumor

Cortical Resting Motor Threshold Difference in Asleep- Awake Craniotomy for Motor Eloquent Gliomas: WHO Grading influences motor pathway excitability

Sunday, May 5, 2024
2:27 PM – 2:29 PM CT
Location:  S405a
Disclosure(s):
Prajwal Ghimire, MSc, MD: No financial relationships to disclose
Introduction: Intraoperative knowledge of diffuse glioma biology can impact the resection strategy. Developing neurophysiological tools to predict WHO tumour grading can empower the treating teams for a better surgical decision-making process.

Methods: Thirty-eight patients with supratentorial diffuse gliomas underwent asleep-awake-sedated craniotomies for tumour removal under intraoperative neuromonitoring. The resting motor threshold (RMT) was calculated for different train stimulation paradigms (single pulse to a train-of-5 pulses) during awake and asleep phases. Receiver operating characteristic (ROC) analysis and Bayesian regression models were performed to analyze the prediction of tumour grading based on the RMT differences.

Results: Significant positive spearman correlations were observed between RMT excitability difference and WHO tumour grade for train stimulation paradigms of 5 (R=0.54, P=0.00063), 4 (R=0.49, P=0.002), 3 (R=0.51, P=0.001), and 2 pulses (R=0.54, P=0.0007). No significant correlation was found for single-pulse stimulation (R=0.34, P=0.15). Kruskal-Wallis analysis of the median revealed a positive significant difference between the median of excitability difference and WHO tumour grade in all but the single pulse paradigms - train-of-5, P=0.008, train-of-4, P=0.01, train-of-3, P=0.009, train-of-2, P=0.005 and single pulse P=0.35. ROC analysis showed 3mA difference - train-of-4, AUC=0.7621; train-of-3, AUC=0.8076 and train-of-2, AUC=0.7500 - as the best predictor of high-grade glioma across different patterns of motor pathway stimulation (AUC = 0.8250 in the Combined Multi-Train Score using previous findings). Bayesian regression found that an excitability difference above 3mA would indicate a 75.8% probability of a glioma being high grade.

Conclusion : Our results suggest that cortical motor excitability difference between the asleep and awake phases in glioma surgery could correlate with tumour grade. This could be a useful tool to guide tumour resection during surgery.