Insular Glioma Systematic Reviews and Meta-analysis

• Prognostic Factors and Resectability Predictors in Insular Gliomas: A Systematic Review
• Seizure outcome after resection of insular glioma: a systematic review, meta-analysis, and institutional experience
• Post-operative morbidity ensuing surgery for insular gliomas: a systematic review and meta-analysis
• Updated incidence of neurological deficits following insular glioma resection: A systematic review and meta-analysis
• Association Between IDH1 and IDH2 Mutations and Preoperative Seizures in Patients with Low-Grade Versus High-Grade Glioma: A Systematic Review and Meta-Analysis

A Systematic Review and Meta-analysis of Matthias Simon et al., estimated rates of motor and speech deficits epilepsy control, KPI, and functional outcomes, surgical approaches and intraoperative strategies, gaps and open research questions

• Literature search and inclusion criteria were clearly defined.
• Pooled data using a random-effects model.
• PRISMA flowchart included in the full text.

Strengths:

• Solid meta-analytic approach
• Wide timespan and adequate sample size

Limitations:

• No formal risk-of-bias assessment reported
• Lack of subgroup analyses by tumor grade or patient characteristics

• Motor deficits: 6.8%
• Speech deficits: 3.6%
• Postoperative epilepsy control: 79.6%
• KPI ≥ 80: 83.5%

Technical Insights:

• Awake surgery: Slightly better functional outcome, but possibly less extent of resection
• Transcortical approach: Fewer motor deficits than transsylvian

Limitations:

• Pooled results do not reflect institutional variability
• Lack of detail on long-term seizure outcome (e.g., Engel class)

• Risks and complication rates are comparable to other neuro-oncological procedures.
• Mapping and monitoring are recommended, ideally in experienced hands.

Criticisms:

• Underrepresents the steep insular glioma surgery learning curve and required surgical expertise
• No GRADE assessment of evidence
• Brief treatment of insular glioblastomas

• Absence of standardized functional outcome reporting
• Poorly defined classification systems (Yasargil vs. Berger-Sanai vs. Duffau)
• Limited evidence on high-grade (GBM) surgery in insula

• Highly valuable reference for experienced neuro-oncology teams.
• Not generalizable to centers with limited awake surgery capacity.
• Future work should focus on:
  • Standardized outcomes
  • Prospective multicenter registries
  • Better classification of insular gliomas and their growth patterns

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