Does Preoperative Bilsky Score Predict Outcome Following Surgical Resection of Primary Tumors of the Spine?

OBJECTIVE: In patients undergoing surgery for primary bone tumors of the spine, we sought to compare Bilsky score 0-1 versus 2-3 in: 1) preoperative presentation, 2) perioperative variables, and 3) long-term outcomes. METHODS: A single-center, retrospective cohort study was undertaken of patients undergoing surgery for extradural, primary bone tumors of the spine between January 2010 and January 2021. The primary exposure variable was Bilsky score, dichotomized as 0-1 versus 2-3. Survival analysis was performed to assess local recurrence (LR) and overall survival (OS). RESULTS: Of 38 patients undergoing resection of primary spinal tumors, 19 (50.0%) patients presented with Bilsky 01 and 19 (50.0%) Bilsky 2-3 grades. The most common diagnosis was chondrosarcoma (33.3%), followed by chordoma (16.7%). There were 15 (62.5%) malignant tumors. Preoperatively, there was no significant difference in demographics, Karnofsky Performance Scale (KPS) ( P > 0.999), or motor deficit ( P > 0.999). Perioperatively, no difference was found in operative time ( P = 0.954), blood loss ( P = 0.416), length of stay ( P = 0.641), neurologic deficit ( P > 0.999), or discharge disposition ( P = 0.256). No difference was found in Enneking resection status (69.2% vs. 54.5%, P = 0.675). Long-term, no differences were found regarding reoperation ( P = 0.327), neurologic deficit ( P > 0.999), postoperative KPS ( P = 0.605) and modified McCormick Scale (MMS) ( P = 0.870). No difference was observed in KPS ( P = 0.418) and MMS ( P = 0.870) at last follow-up. However, patients with Bilsky 2-3 had shorter time to LR (1715.0 vs. 513.0 +/- 633.4 days, log-rank; P = 0.002) and shorter OS (2025.0 +/- 1165.3 vs. 794.0 +/- 952.6 days, log-rank; P = 0.002). - CONCLUSIONS: Bilsky 2-3 lesions were associated with shorter time to LR and shorter OS. Patients harboring primary spinal tumors with higher grade Bilsky score appear to be at a higher risk for worse outcomes.