Feasibility of intraoperative neuromonitoring and cortical/subcortical mapping in patients with cerebral lesions of highly functional localizations-pathway to case adapted monitoring and mapping procedures

[Microsurgical resection of dominant hemisphere gliomas with intraoperative speech mapping by a staff neurologist]

Intraoperative awakening with speech mapping is used to minimize the risk of irreparable neurological deficit in patients with tumors located near speech zones. However, the lack of staff neurolinguist or neuropsychologist in the majority of neurosurgical departments is one of the limiting factors.

OBJECTIVE

To analyze surgical treatment of patients with glial tumors near speech and motor centers using intraoperative awakening with speech mapping by staff neurologist.

MATERIAL AND METHODS

We analyzed postoperative outcomes in 15 patients with dominant hemisphere gliomas of functionally significant areas between 2020 and 2024. All surgeries were accompanied by multimodal neurophysiological monitoring including intraoperative awakening and mapping by staff neurologist without neuropsychologist or neurolinguist. Intraoperative contrast-enhanced MRI was performed in 3 (20.0%) patients (T2WI and T1WI). Postoperative MRI was performed on the first postoperative day in all patients for objective assessment of resection quality.

RESULTS

Total resection was achieved in 13 (86.7%) cases, subtotal - in 2 (13.3%) cases. In 11 (73.3%) patients, no postoperative neurological deficit was detected. Three (20.0%) patients had transient speech impairment with regression throughout a month. Persistent deficit developed in 1 (6.7%) patient.

CONCLUSION

Standardized speech mapping methods and staff neurologist for cortical mapping during resection of gliomas near functionally significant speech zones maintain high extent of resection without higher risk of permanent speech disorders. Widespread speech mapping by staff neurologists of neurosurgical departments will increase the number of function-preserving surgeries in all regions of the Russian Federation.

Establishment of Different Intraoperative Monitoring and Mapping Techniques and Their Impact on Survival, Extent of Resection, and Clinical Outcome in Patients with High-Grade Gliomas-A Series of 631 Patients in 14 Years

BACKGROUND

The resection of brain tumors can be critical concerning localization, but is a key point in treating gliomas. Intraoperative neuromonitoring (IONM), awake craniotomy, and mapping procedures have been incorporated over the years. Using these intraoperative techniques, the resection of eloquent-area tumors without increasing postoperative morbidity became possible. This study aims to analyze short-term and particularly long-term outcomes in patients diagnosed with high-grade glioma, who underwent surgical resection under various technical intraoperative settings over 14 years.

METHODS

A total of 1010 patients with high-grade glioma that underwent resection between 2004 and 2018 under different monitoring or mapping procedures were screened; 631 were considered eligible for further analyses. We analyzed the type of surgery (resection vs. biopsy) and type of IONM or mapping procedures that were performed. Furthermore, the impact on short-term (The National Institute of Health Stroke Scale, NIHSS; Karnofsky Performance Scale, KPS) and long-term (progression-free survival, PFS; overall survival, OS) outcomes was analyzed. Additionally, the localization, extent of resection (EOR), residual tumor volume (RTV), IDH status, and adjuvant therapy were approached.

RESULTS

In 481 patients, surgery, and in 150, biopsies were performed. The number of biopsies decreased significantly with the incorporation of awake surgeries with bipolar stimulation, IONM, and/or monopolar mapping (p < 0.001). PFS and OS were not significantly influenced by any intraoperative technical setting. EOR and RTV achieved under different operative techniques showed no statistical significance (p = 0.404 EOR, p = 0.186 RTV).

CONCLUSION

Based on the present analysis using data from 14 years and more than 600 patients, we observed that through the implementation of various monitoring and mapping techniques, a significant decrease in biopsies and an increase in the resection of eloquent tumors was achieved. With that, the operability of eloquent tumors without a negative influence on neurological outcomes is suggested by our data. However, a statistical effect of monitoring and mapping procedures on long-term outcomes such as PFS and OS could not be shown.