Effect of Minimally Invasive Spine Stabilization in Metastatic Spinal Tumors

Background and Objectives: There have been numerous advances in spine surgery for metastatic spinal tumors, and minimally invasive spine stabilization (MISt) is becoming increasingly popular in Japan. MISt is a minimally invasive fixation procedure that temporarily stabilizes the spine, thereby reducing pain, preventing pathological fractures, and improving activities of daily living at an early stage. MISt may be useful given the recent shift toward outpatient cancer treatment. Materials and Methods: This study enrolled 51 patients with metastatic spinal tumors who underwent surgery using MISt between December 2013 and October 2020. The Spinal Instability Neoplastic Score, an assessment of spinal instability, was used to determine the indication for surgery, and the Epidural Spinal Cord Compression scale was used for additional decompression. Results: The patients comprised 34 men and 17 women, and the mean age at surgery was 68.9 years. The mean postoperative follow-up period was 20.8 months, and 35 of 51 patients (67%) had died by the last survey. The mean operative time was 159.8 min, mean blood loss was 115.7 mL, and mean time to ambulation was 3.2 days. No perioperative complications were observed, although two patients required refixation surgery. Preoperatively, 37 patients (72.5%) were classified as Frankel grade E. There were no cases of postoperative exacerbation, and six patients showed improvement of one or more Frankel grades after surgery. The median duration of patient survival was about 22.0 months. Patients with breast, prostate, renal, and thyroid cancers had a good prognosis, whereas those with gastrointestinal and head and neck cancers had a poor prognosis. Conclusions: MISt can benefit patients who are ineligible for conventional, highly invasive surgery and is also suitable because cancer treatment is increasingly performed on an outpatient basis. Furthermore, choosing the right surgery for the right patient at the right time can significantly affect life expectancy.