Navigated Transcranial Magnetic Stimulation-Guided Positioning of Strips for Cortico-Cortical Evoked Potentials in Temporal Lobectomy for Epileptogenic Low Grade Gliomas Under General Anesthesia: Our Experience and the Systematic Review.

Abstract

To evaluate the strip placement with navigated transcranial magnetic stimulation (nTMS) for cortico-cortical evoked potentials (CCEPs) in monitoring the arcuate fasciculus in temporal lobectomy under general anesthesia for epileptogenic temporal low-grade glioma. We collected a series of epileptogenic temporal low-grade gliomas that underwent temporal lobectomy under general anesthesia between November 2022 and December 2023. The positioning of the strips for CCEPs was guided by the nTMS positive points on neuronavigation. Postoperative follow-up was for 3 months. We conducted a systematic review according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines up to 7th April 2025 for craniotomy size and tools for positioning the strips/grid for CCEP. We enrolled 13 patients, but five were excluded due to the scarce reproducibility of the CCEP curve. The CCEP was performed in 61.5% of temporal lobectomies. All 8 included cases had electrodes at the craniotomy edge or more than 1 cm from the edge of the craniotomy. Postoperative aphasia occurred in 3 patients (37.5% prevalence), all of them with a preoperative mild deficit. CCEP demonstrated 100% sensitivity and 80% specificity as a language monitoring tool (area under the curve 0.9, P = 0.0001, standard error 0.1, 95% confidence interval 0.5-0.9). There were 14 articles (all case series) that met our inclusion/exclusion criteria for the systematic review. Placing strips for CCEPs through nTMS allows for small craniotomies. CCEPs are a valuable tool for predicting postoperative aphasia. To our knowledge, this is the first paper that reports the performance of the CCEP in the temporal lobectomy.