Microsurgery Versus Embolization for Spinal Cord Arteriovenous Malformations: A Proposed Grading System

Neurosurgery 98:786–798, 2026

This study proposes a four-parameter grading system to stratify angioarchitectural complexity of spinal cord arteriovenous malformations (SCAVMs) and compares clinical outcomes of microsurgery versus endovascular embolization across five grades in a 714-patient multicenter cohort. The grade sums points for metameric manifestation, lesion diameter ≥2 cm, anterior sulcal artery supply, and lesion depth, predicting incomplete resection with strong ROC (receiver-operating characteristic) performance.

Results show embolization as the preferred primary treatment owing to lower immediate risk, while microsurgery achieves higher complete obliteration for low-grade lesions (scores 0–1) but carries greater treatment-related deterioration and worse long-term prognosis for higher grades (scores 2–4). Recommendations prioritize embolization, reserving microsurgery for select low-grade or high-risk patients when embolization fails.

Study aim Compare outcomes of microsurgery vs endovascular embolization for SCAVMs by introducing a grading system that stratifies angioarchitectural complexity to enable fairer comparisons.

Cohort & design Retrospective multicenter analysis of 714 SCAVM patients treated (2007–2022); 308 received microsurgery (often after failed/partial embolization) and 406 received exclusive embolization.

Grading system (0–4 points) One point each for anterior sulcal artery supply, metameric manifestations, maximum lesion diameter ≥2 cm, and embedded (deep) lesion depth; total score defines grade.

Predictors basis & performance The four grading variables were independent predictors of incomplete resection in microsurgical cases, and the score showed strong ROC discrimination in modeling and validation groups (AUC ≈ 0.83).

Overall treatment tradeoff Microsurgery achieved a higher complete obliteration rate (61.7% vs 24.4%) but had higher treatment-related deterioration (19.8% vs 4.2%) and higher poor prognosis at last follow-up (52.3% vs 36.2%) than exclusive embolization.

Low grades (0–2) obliteration For scores 0–2, microsurgery produced significantly higher complete obliteration than embolization; for scores 3–4, complete obliteration rates were similar between methods.

Long-term deterioration & prognosis by grade Long-term clinical deterioration after embolization was higher for score 1 (significant) and also higher for score 0 (not significant); for scores 2–4, long-term deterioration risk was comparable, while poor prognosis was generally worse with microsurgery except score 0 (similar).

Treatment strategy Embolization should be the primary approach for SCAVMs; microsurgery is an alternative if embolization fails to fully obliterate lesions in score 0 (recommended) and selected 1-point patients (optional, especially higher clinical risk), but not first-line for scores 2–4.