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 via the Frankel grade system, and functional status was measured using the Karnofsky performance scale (KPS) preoperatively and at 3, 6, and 12 months after surgery. Local control was evaluated based on X-ray, CT, or MRI examination. Survival time and perioperative complications were also documented. 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.