Factors Associated with Postoperative Neurologic Improvement after Endovascular Treatment for Spinal Vascular Lesions: Japanese Registry of Neuroendovascular Therapy 2, 3, and 4

BACKGROUND AND PURPOSE: Data regarding predictive factors for postoperative neurological improvement after endovascular treatment for spinal vascular lesions are extremely limited. Our aim was to perform a subgroup analysis of spinal vascular lesions from the Japanese Registry of Neuroendovascular Therapy (JR-NET) 2-4 (2007-2019) to review the current status of endovascular treatment for spinal vascular lesions in Japan and to identify factors associated with postoperative neurologic improvement after endovascular treatment for spinal vascular lesions. MATERIALS AND METHODS: The treatment statuses of 384 spinal dural arteriovenous fistula (SDAVF), 115 spinal perimedullary arteriovenous fistula (SPAVF), and 56 spinal intramedullary arteriovenous malformation (SIAVM) cases were assessed along with the correlations between each variable and the primary end point of postoperative neurologic improvement. RESULTS: Treatment was radical in 81.9% of SDAVFs, palliative or presurgical in 73.2% of SIAVMs, and radical or palliative/presurgical in 47.0% and 51.3%, respectively, of SPAVF cases. Total occlusion was achieved in 60.2% of SDAVF, 30.4% of SPAVF, and 17.9% of SIAVM cases. Treatment-related complications occurred in 7.3% of SDAVF, 14.8% of SPAVF, and 8.9% of SIAVM cases. Postoperative neurologic improvement was achieved in 52.3% of SDAVF, 28.7% of SPAVF, and 23.2% of SIAVM cases. In multivariate analyses, such improvement in SDAVFs was correlated with total shunt obliteration and the absence of complications. Postoperative neurologic improvement in SPAVFs was associated with the absence of complications and was inversely associated with hemorrhagic onset in multivariate analyses. In SIAVM, a negative correlation with hemorrhagic onset was found in only univariate analysis. For the analysis of treatment outcomes by institutional case volume, total obliteration of SDAVFs and postoperative neurologic improvement of SPAVFs were significantly higher in the high-volume group. CONCLUSIONS: In Japan, treatment of spinal vascular lesions was administered with relative safety, and better outcomes were achieved at high-volume centers. In SDAVFs, total shunt obliteration and avoidance of complications are critical factors for achieving neurologic recovery. In SPAVFs, selecting an appropriate treatment strategy based on the vascular architecture is essential to minimize complications for achieving favorable postoperative outcomes. In SIAVMs, disease management should take precedence over radical intervention. Furthermore, the disruption of neurologic recovery by hemorrhagic onset in both SPAVFs and SIAVMs highlights the importance of early diagnosis and timely intervention.