SURG-36. Nationwide Analysis of Intracranial Tumor Embolization in Japan: 2,756 Cases from the JR-NET4 Registry

Abstract BACKGROUND In Japan, embolization of intracranial tumors is commonly performed as a preoperative adjunct to neurosurgical resection. The Japanese Registry of NeuroEndovascular Therapy (JR-NET), established in 2005, aims to identify factors influencing the outcomes of neuroendovascular procedures. JR-NET4, the latest phase of this registry, provides real-world data on the practice of intracranial tumor embolization across Japan. Patients and Methods JR-NET4 is a nationwide, multicenter, retrospective observational study that collected data from 166 neurosurgical centers between January 2015 and December 2019. Of 63,230 total registered cases, 2,664 patients (4.2%) underwent embolization for intracranial tumors. After excluding 61 cases with incomplete data, 2,603 patients were included in the analysis. Patient demographics, procedural details, and outcomes were evaluated. The primary endpoint was a modified Rankin Scale (mRS) score of 0–2 at 30 days post-procedure. Secondary endpoints included rates and types of procedure-related complications. RESULTS The final cohort included 2,603 patients (1,612 females; median age: 61 years, interquartile range 51–71). Favorable outcomes (mRS 0–2) at 30 days were observed in 86.9% of patients. The overall complication rate was 4.8%, including 1.8% hemorrhagic, 2.0% ischemic, and 1.0% other complications. Multivariate analysis revealed that general anesthesia and embolization of arteries other than the external carotid artery were significant risk factors for complications. Among tumor types, meningiomas had a 4.3% complication rate (3.5% major), while hemangioblastomas showed a higher complication rate of 14.9% (9.9% major). CONCLUSION JR-NET4 provides comprehensive, real-world evidence on intracranial tumor embolization in Japan. The findings underscore the safety and utility of the procedure while identifying key risk factors that may guide clinical decision-making in neuroendovascular therapy.