Role of Transcranial Motor Evoked Potentials in Anterior and Middle Skull Base Meningiomas Surgery

Objective: Despite technological and microsurgical advancement, surgical resection of skull base meningiomas with complete motor function preservation still represents a troublesome issue in Neurosurgery. The impact of intraoperative transcranial motor evoked potentials (t-MEPs) monitoring on the resection of these tumors has not been entirely clarified so far. The purpose of this work is to examine if and how t-MEPs may affect postoperative motor function and whether specific features of the lesions may be predictive of an intraoperative t-MEPs alteration and a postoperative motor deficit.

Methods: One hundred and eleven patients, 113 craniotomies, and 115 lesions were finally enrolled in the study. Patients were divided in two groups based on the use of intraoperative neuromonitoring of t-MEPs. Seventy-five of 115 (65.2%) cases were included in the “IOM Group,” 40/115 (34.8%) in the “No IOM Group.” Transcranial MEPs monitoring was used in case of (1) dislocation/encasement of the arteries of the circle of Willis and/or their perforating branches; (2) dislocation of cortico-spinal tract and/or brainstem; (3) preoperative motor deficit.

Results: The overall new-onset postoperative hemiparesis rate in our series was 2/115 cases (1.7%), a significantly lower result than the main series of the literature. In 7/75 cases in “IOM Group,” an intraoperative t-MEPs amplitude reduction was observed, and several surgical “rescue” maneuvers were performed. None of these patients developed postoperative paresis. Fisher’s exact test was used in order to investigate any association between the tumor location and the risk of intraoperative t-MEPs alteration. Data from statistical analysis pointed out that clinoid, petroclival region, tuberculum sellae and olfactory groove (if larger than 55 mm) meningiomas are related to higher risk of intraoperative t-MEPs amplitude reduction, and hence, to a higher risk of postoperative paresis (p = 0.0018).

Conclusion: Intraoperative t-MEPs monitoring may represent a valid help for reducing the frequency of new-onset postoperative paresis in skull base meningioma surgery, in particular for high-risk location in which intraoperative monitoring may be especially recommended

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Artikel online veröffentlicht:
05. Februar 2024