Clinical Report: Direct Cortical vs Transcranial Magnetic Stimulation in Brain Tumor Surgery

Overview

This systematic review and meta-analysis compared direct cortical stimulation (DCS) and transcranial magnetic stimulation (TMS) for mapping eloquent brain areas during tumor surgery. Fourteen studies from 2010 to 2023 were analyzed, focusing on clinical outcomes and adverse events to assess efficacy and safety.

Background

Brain tumors, including primary and metastatic lesions, pose significant mortality and morbidity challenges, especially when located near eloquent brain regions responsible for critical neurological functions. Surgical resection in these areas risks permanent deficits, making precise functional mapping essential. Direct cortical stimulation (DCS) is the gold standard intraoperative mapping technique but is invasive. Transcranial magnetic stimulation (TMS) offers a non-invasive alternative with potential comparable efficacy. This study systematically reviews and meta-analyzes comparative data on DCS versus TMS to guide surgical planning.

Data Highlights

A total of 918 studies were initially identified, with 14 comparative studies meeting inclusion criteria for meta-analysis. The studies spanned 2010 to 2023 and included patients undergoing brain tumor surgery with either DCS or TMS mapping. Quality assessment was performed using the ROBINS-1 tool. Meta-analyses employed fixed or random effects models based on study homogeneity (I2 test), with results presented in forest plots and publication bias assessed via funnel plots.

Key Findings

• DCS remains the most sensitive and reliable method for intraoperative mapping of eloquent cortex but is invasive.
• TMS provides a non-invasive alternative with promising efficacy in preoperative functional mapping.
• Meta-analysis showed no statistically significant difference in adverse neurological outcomes between DCS and TMS groups.
• Studies included were mostly non-randomized, highlighting the need for higher-level evidence.
• Mapping with either technique aids in maximizing tumor resection while preserving neurological function.
• Publication bias was assessed and minimized through comprehensive literature search and funnel plot analysis.

Clinical Implications

Clinicians can consider TMS as a less invasive preoperative mapping tool that may complement or, in some cases, substitute for DCS, especially when invasive mapping poses higher risk. Both techniques contribute to safer resections near eloquent brain areas, potentially improving postoperative neurological outcomes and patient quality of life. However, surgical teams should weigh the current evidence limitations and individual patient factors when selecting mapping modalities.

Conclusion

This systematic review and meta-analysis support the clinical utility of both DCS and TMS in brain tumor surgery for eloquent area mapping, with comparable safety profiles. Further randomized controlled trials are warranted to strengthen evidence and optimize mapping strategies.

References

1. GLOBOCAN 2020 -- Global Cancer Observatory
2. Neuro-Oncology Multidisciplinary Care -- Clinical Practice
3. Survival Rates in Malignant Brain Tumors -- Epidemiology Study
4. Neurological Symptoms in Brain Tumor Patients -- Clinical Correlation
5. Risks of Resection in Eloquent Brain Areas -- Neurosurgical Outcomes
6. Eloquent Cerebral Structures and Neuro-Oncology Damage -- Review
7. Direct Cortical Stimulation as Gold Standard -- Neurosurgical Mapping
8. Transcranial Magnetic Stimulation in Brain Tumor Surgery -- Emerging Technique