Outcomes and Prognosis of Neurological Decompression and Stabilization for Spinal Metastasis: Is Assessment with the Spinal Instability Neoplastic Score Useful for Predicting Surgical Results?

STUDY DESIGN: Retrospective study. PURPOSE: To evaluate the efficacy of the Spinal Instability Neoplastic Score (SINS) in predicting surgical outcomes and survival. Patients were categorized into two groups according to the SINS, and their surgical outcomes and survival following decompression and stabilization were assessed. OVERVIEW OF LITERATURE: Palliative surgery in patients with a life expectancy ≥3 months may effectively improve their overall condition in the long term. Currently, the effectiveness of the SINS for predicting surgical results and survival remains controversial. METHODS: This study included 44 patients who underwent decompression and stabilization for spinal metastases at Yokosuka Kyosai Hospital between 2008 and 2017. The patients were divided into two groups: stable (SINS ≤12) and unstable (SINS ≥13). Changes in the Frankel score and Eastern Cooperative Oncology Group Performance Status (ECOG-PS) were compared between the two groups, and patient survival was evaluated according to the SINS, Tokuhashi score, and Katagiri score. RESULTS: The stable group (SINS range, 7–12) included 24 patients while the unstable group (SINS range, 13–16) included 20 patients. The Frankel score significantly improved from 2.8 to 3.6 in the stable group (p <0.001) and from 2.7 to 3.9 in the unstable group (p <0.001). The ECOG-PS significantly improved from 3.2 to 2.1 in the stable group (p <0.001) and from 3.0 to 1.8 in the unstable group (p <0.001). There was a statistically significant difference in median survival between the two groups. CONCLUSIONS: All patients treated with palliative surgery showed favorable outcomes, as indicated by improved the Frankel score and ECOG-PS following surgery. However, median survival was significantly better in the stable group. The results of this study indicate that the SINS is appropriate for surgical decision making and may be used to predict survival.