Awake Tumor Resection with Direct Electrical Stimulation and Real-Time Cognitive Assessment

Overview

Awake craniotomy using direct electrical stimulation (DES) combined with real-time cognitive monitoring is the gold standard for diffuse low-grade glioma resection. This approach enables maximal tumor removal while preserving critical brain functions, resulting in low permanent deficit rates and high return-to-work outcomes.

Background

Awake surgery with DES was initially developed for epilepsy and later adapted for brain tumor resection, particularly diffuse low-grade gliomas (DLGG). Unlike traditional anatomical boundaries, this technique relies on the patient’s individual connectome and real-time cognitive testing to guide resection. Functional preservation is prioritized by mapping eloquent cortical and subcortical areas intraoperatively, tailored to each patient’s unique functional profile and goals. This paradigm shift has significantly improved onco-functional outcomes and long-term survival.

Data Highlights

Reported outcomes include less than 2% permanent neurological deficits, approximately 94% return-to-work rates, and survival extending beyond 20 years following awake tumor resection with DES mapping.

Key Findings

• Preoperative comprehensive cognitive and language assessments are essential to establish baselines and tailor intraoperative tasks.
• Patient positioning in lateral decubitus with the contralateral arm free optimizes cooperation and monitoring.
• Local anesthesia of pin sites and skin incisions with epinephrine ensures hemostasis and patient comfort.
• Cortical mapping is performed awake with neuropsychologist-led cognitive tasks; stimulation intensity is calibrated at the ventral premotor cortex starting at 1 mA and capped at 5 mA to minimize seizure risk.
• Functional sites identified by DES are tagged intraoperatively to guide safe tumor resection.
• Preservation of vascular supply during resection is critical to maintain surrounding cortical function.

Clinical Implications

Implementing awake craniotomy with DES and real-time cognitive assessment requires multidisciplinary coordination including neuropsychology and anesthesiology. Tailoring cognitive tasks to the patient’s functional profile enables maximal tumor resection while preserving quality of life. Avoidance of sedatives preoperatively and careful intraoperative management reduce complications and improve patient cooperation.

Conclusion

Awake tumor resection guided by direct electrical stimulation and real-time cognitive monitoring represents a personalized, function-preserving surgical approach that improves long-term neurological and oncological outcomes in patients with diffuse low-grade gliomas and other brain tumors.

References

1. Duffau 2022 -- Awake Surgery with Direct Electrical Stimulation Mapping