Microsurgical Resection versus Endovascular Embolization for Intramedullary Spinal Arteriovenous Malformations: A Systematic Review, Meta-Analysis, and Regression Modeling.

Background

Intramedullary spinal arteriovenous malformations (sAVMs) are rare, high-risk lesions associated with progressive neurological decline, ischemia, and hemorrhage. Microsurgical resection (MR) and endovascular embolization (EE) are the primary treatment modalities, but their comparative efficacy and safety remain unclear.

Purpose

To systematically compare angiographic and clinical outcomes of MR versus EE for intramedullary sAVMs. DATA SOURCES A systematic literature search of PubMed and Embase was performed across major medical databases to identify relevant studies reporting outcomes of MR or EE in intramedullary sAVMs. STUDY SELECTION Studies including ≥5 patients with intramedullary sAVMs treated with MR or EE and reporting angiographic obliteration and clinical outcomes were included. DATA ANALYSIS Random-effects meta-analysis was used to estimate pooled outcome rates. Multivariable mixed-effects meta-regression identified predictors of angiographic and clinical outcomes. DATA SYNTHESIS Twenty-six studies were included (MR: 193 patients; EE: 303 patients). Baseline characteristics were generally comparable between groups, although MR patients had slightly higher pain presentation, glomus type lesions, and prior treatment. MR achieved significantly higher complete obliteration rates than EE (80.13% vs 27.44%, p<0.01). There were no significant differences in symptom improvement (42.70% vs 55.52%, p=0.35), complete recovery (36.37% vs 32.58%, p=0.92), worsening (13.81% vs 10.96%, p=0.45), post-treatment hemorrhage (1.83% vs 0.89%, p=0.30), or mortality (1.55% vs 0.99%, p=0.81). Higher obliteration independently predicted symptom improvement, though MR was associated with lower odds of improvement. EE, younger age, and non-hemorrhagic presentation predicted complete recovery.

Limitations

Findings are limited by the retrospective design of included studies, heterogeneity in patient selection and treatment strategies, and potential publication bias.

Conclusions

MR provides higher angiographic obliteration but does not consistently translate to improved clinical recovery, likely due to procedure-related neural injury. EE remains an effective, less invasive option for complex or high-risk lesions, while MR may be best reserved for salvage therapy. Individualized treatment strategies based on lesion characteristics and patient factors are essential.