Object: Surgery of convexity meningiomas is usually considered a low-risk procedure. Nevertheless, the risk of postoperative motor deficits is higher (7.1 – 24.7% of all cases) for lesions located in the rolandic region, especially when an arachnoidal cleavage plane with the motor pathway is not identifiable. We analyzed the possible role of navigated transcranial magnetic stimulation (nTMS) in the definition of surgical strategy for resection of rolandic meningiomas, and in predicting the postoperative motor outcome and the presence/lack of an intraoperative arachnoidal cleavage plane. Methods: We retrospectively collected clinical data from patients affected by convexity, parasagittal or falx meningiomas involving the rolandic region, who were submitted to preoperative nTMS mapping of the motor cortex (M1) and nTMS-based DTI fiber tracking of the corticospinal tract before surgery at two different neurosurgical centers. Surgeons’ self-reported evaluations of the impact of the nTMS-based mapping on surgical strategy were analyzed. Moreover, the nTMS mapping accuracy was evaluated in comparison with intraoperative neurophysiological mapping (IONM) findings. Lastly, we assessed the role of nTMS as well as other pre- and intraoperative parameters for predicting the patients’ motor outcome and the presence/lack of an intraoperative arachnoidal cleavage plane. Results: Forty-seven patients were enrolled. The nTMS-based planning was considered useful in 89.3% of cases, and a change of the surgical strategy was observed in 42.5% of cases. The accuracy of the nTMS-based planning as compared to IONM (35 patients) was 94.2%. A new permanent motor deficit occurred in 8.5% of cases (4 out of 47). A higher nTMS-measured resting motor threshold (RMT) as well as the lack of an intraoperative arachnoidal cleavage plane were the only independent predictors of a poor motor outcome (p=0.04 and p=0.02, respectively). Moreover, a higher RMT was also able to predict the lack of an arachnoidal cleavage plane (p=0.008). No significant predicting role was observed for the preoperative motor status, perilesional edema, T2 cleft sign and contrast-enhancement pattern of the meningioma. Conclusion: The nTMS-based motor mapping could be a useful tool for surgery of rolandic meningiomas, especially when a clear cleavage plane with M1 is not present. Moreover, the RMT seems to be a predictor of the presence/lack of an intraoperative cleavage plane and of the motor outcome, thereby helping the stratification of patients at high risk before surgery.
|Titolo:||SURGERY OF MENINGIOMAS LOCATED IN THE ROLANDIC AREA: THE ROLE OF NAVIGATED TRANSCRANIAL MAGNETIC STIMULATION FOR PREOPERATIVE PLANNING, TUMOR RESECTION, AND OUTCOME PREDICTION|
|Data di pubblicazione:||26-nov-2018|
|Appare nelle tipologie:||Tesi di dottorato|