Insular Glioma Systematic Reviews 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
📊 Methodology
- 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
📈 Main Results
- 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)
🧪 Discussion and Interpretation
- 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
❗ Literature Gaps Identified
- 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
📌 Final Assessment
| Category | Assessment |
|---|---|
| Study Type | Systematic Review + Meta-analysis |
| Methodological Rigor | High (PRISMA, random-effects model) |
| Heterogeneity Handling | Moderate (no deep stratification) |
| Clinical Applicability | High for experienced centers |
| Addresses Gaps? | Partially |
| Overall Value | (4/5) |
📝 Recommendations
- 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
1)
Simon M, Hagemann A, Gajadin S, Signorelli F, Vincent AJPE; EANS Neuro-oncology Section. Surgical treatment for insular gliomas. A systematic review and meta-analysis on behalf of the EANS neuro-oncology section. Brain Spine. 2024 May 15;4:102828. doi: 10.1016/j.bas.2024.102828. PMID: 38859917; PMCID: PMC11163152.