Article
Functional outcome after pre- versus intraoperative language mapping for glioma resection and evaluation of a classification for language eloquence – a comparative cohort study
Funktionelles Outcome nach prä- versus intraoperativer Sprach-Kartierung zur Resektion von Gliomen und Evaluation einer Klassifikation für Sprach-Eloquenz – eine vergleichende Kohorten-Studie
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Published: | June 26, 2020 |
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Objective: A considerable number of gliomas require resection via direct electrical stimulation (DES) during awake craniotomy. Likewise, the feasibility of resecting language-eloquent gliomas purely based on navigated repetitive transcranial magnetic stimulation (nrTMS) has been shown. This study analyzes the outcomes after preoperative nrTMS-based and intraoperative DES-based glioma resection in a substantially large cohort. Likewise, due to the necessity of making location comparable, a classification for language eloquence for gliomas is introduced.
Methods: Between 3/2015 and 5/2019, we prospectively enrolled 100 consecutive cases that were resected based on preoperative nrTMS language mapping (nrTMS group) and 47 cases via intraoperative DES mapping during awake craniotomy (awake group) following a standardized clinical workflow. Outcome measures were determined preoperatively, at 5 days after surgery, and at 3 months after surgery. To make functional eloquence comparable, we developed a classification based on prior publications and our own clinical experience. Groups and classification scores were then correlated with clinical outcomes.
Results: The functional outcome did not differ between groups. However, gross total resection was achieved in more cases of the nrTMS group (87%, vs. 72% in the awake group, p = 0.04). Nonetheless, the awake group showed significantly higher scores of eloquence than the nrTMS group (median 7 points; interquartile range 6-8 vs. 5 points; 3-6.75; p < 0.0001).
Conclusion: Resecting language-eloquent gliomas purely based on nrTMS data is feasible in a high percentage of cases if the described clinical workflow is followed. Moreover, the proposed classification for language eloquence makeslanguage-eloquent tumors comparable, as shown by its correlation with functional and radiological outcomes.