Awake surgery for glioma

Craniotomies for glioma surgery under conscious sedation (CS) have been well-documented in the literature for glioma surgery that are in or adjacent to eloquent areas ^{1) 2) 3) 4) 5)}.

Awake surgery for glioma aims to maximize resection to optimize prognosis while minimizing the risk of postoperative deficits.

The oncological and functional results of awake glioma surgery during the learning curve are comparable to results from established centers. The use and utility of resection probability maps are well demonstrated. The return to work level is high ⁶⁾.

AC with the input of the speech and language therapist (SLT) and an experienced neuro-physiotherapist (NP) is a key component in ensuring optimal functional outcomes for patients with gliomas in eloquently located areas ⁷⁾.

5 aminolevulinic acid guidance during awake craniotomy

Awake surgery for insular glioma

Awake surgery for insular glioma

Systematic reviews

To determine the benefit of awake craniotomy for language, motor, and neurological functions, as well as other clinical outcomes, Bu et al. searched Medline, Embase, the Cochrane Library, and the Chinese Biomedical Literature Database up to December 2019. Gray literature was also searched. They included randomized and non-randomized controlled studies comparing awake craniotomy versus general anesthetic resection and reporting the language and neurological outcomes. Ten studies with 833 patients were included in the meta-analysis. The pooled risk ratio (RR) suggested no significant differences in language and neurological outcomes between the general anesthesia group and the awake craniotomy group without electrical stimulation. Awake craniotomy with electrical stimulation, however, was associated with improved late language and neurological outcomes (≥ 3 months) versus general anesthesia with pooled RR of 0.44 (95% CI = 0.20-0.96) and 0.49 (95% CI = 0.30-0.79), respectively. Awake craniotomy with electrical stimulation was also associated with a better extent of resection with the pooled RR of 0.81 (95%CI = 0.71-0.92) and shorter hospital stay duration with the pooled weighted mean difference (WMD) of – 1.14 (95%CI = – 1.80 to – 0.48). This meta-analysis suggested that the application of awake craniotomy with electrical stimulation during glioma resection is associated with lower risks of long-term neurological and language deficits and higher extent of tumor resection, as well as shorter hospital stay duration ⁸⁾.

Case series

Mandonnet et al. reported a case series of four patients operated on for a glioma in awake conditions and in whom task-based functional magnetic resonance imaging (fMRI) demonstrated right-dominant activity during a language production task. Language functional sites were identified intraoperatively by Electrostimulations only in the patient with a right-sided lesion. Furthermore, the pre- or postoperative cognitive evaluations in the three patients operated on for a left-sided glioma revealed right spatial neglect and dysexecutive syndrome, hence demonstrating that, in patients with right-dominant activity on language fMRI, the left hemisphere is implicated in spatial consciousness and cognitive control. This study supports the interest of presurgical task-based language fMRI to identify patients with a reversed lateralization of cognitive functions and to make an adequate selection of the battery of intraoperative cognitive tasks to be monitored in those rare outliers ⁹⁾.

Case reports

Corns et al. describe the case of a patient with recurrent left frontal GBM encroaching on Broca’s area (eloquent brain). Gross total resection of the tumour was achieved by combining two techniques, awake resection to prevent damage to eloquent brain and 5-ALA fluorescence guidance to maximise the extent of tumour resection.This technique led to gross total resection of all T1-enhancing tumour with the avoidance of neurological deficit. The authors recommend this technique in patients when awake surgery can be tolerated and gross total resection is the aim of surgery ¹⁰⁾.

References