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

[BACKGROUND AND OBJECTIVES] Comparing microsurgery and embolization for spinal cord arteriovenous malformations (SCAVMs) is challenging because of the disease's rarity and the highly heterogeneous angioarchitecture. The aim of this study was to compare outcomes between microsurgery and embolization using a grading system for SCAVMs that effectively stratifies angioarchitectural complexities.

[METHODS] A total of 714 patients were included, with 308 undergoing microsurgery. The grading system was developed based on independent risk factors of incomplete resection, including anterior sulcal artery supply, metameric manifestations, the maximum diameter of lesion, and lesion depth. Each parameter was assigned one point, stratifying angioarchitectural complexities of SCAVMs into five grades.

[RESULTS] Microsurgery carried significantly higher treatment risks than embolization across all grades. For patients scoring 0 to 2 points, microsurgery achieved significantly higher complete obliteration rates than embolization. For patients scoring 3 or 4 points, the complete obliteration rates between the two methods were similar. Long-term clinical deterioration after microsurgery was significantly more frequent after embolization for patients scoring 1; for patients scoring 0, the higher long-term deterioration rate after embolization was also observed, but not statistically significant; for patients scoring 2 to 4 points, risks of long-term clinical deterioration between the two methods were comparable. At the last follow-up, the rate of poor prognosis was similar between the two methods for patients scoring 0 points. For the remaining groups, microsurgery showed a worse prognosis.

[CONCLUSION] Embolization should be the primary treatment option for patients with SCAVMs; however, microsurgery should be considered as an alternative for patients scoring 0 or 1 point if endovascular treatment fails to achieve complete obliteration.