Pilot study of separation surgery with intraoperative radiotherapy (IORT) for spine metastasis.

Objective: This study aimed to introduce a novel modified separation surgery combined with intraoperative radiotherapy (MSS-IORT) treatment strategy for spinal metastasis and evaluate its efficacy and safety. Methods: A prospective study was conducted from January 2023 to June 2024. Patients with spinal metastasis exhibiting epidural spinal cord compression (ESCC) ≥ 2 grades and spinal instability neoplastic score (SINS) ≥ 7 were enrolled and underwent MSS-IORT. During the procedure, a dose of 8-10 Gy of IORT was administered to the tumor-invaded vertebrae segments during modified separation surgery. Pain intensity was assessed using the visual analog scale (VAS) preoperatively and at 1 week, 3 months, 6 months, and 12 months postoperatively. Neurological function was evaluated Results: A total of 38 patients (median age: 60 years) with 46 involved vertebrae were treated with MSS-IORT. The mean operation time was 277.5 min, and the mean blood loss was 750 ml. After a mean follow-up of 174.5 days, the VAS score decreased significantly postoperatively and continued to decline over time. The KPS score increased significantly at 6 and 12 months, and the Frankel grade significantly improved at 12 months. Local control failure occurred in 3 patients, and 13 experienced adverse events without IORT. Conclusion: The MSS-IORT strategy demonstrates both safety and efficacy, representing a promising treatment option for spine metastases, particularly in patients with ESCC grades ≥ 2 and SINS ≥ 7.