Assistant Professor of Neurosurgery and Orthopaedics Vanderbilt University Medical Center Nashville, Tennessee, United States
Introduction: Spinal cord compression caused by spinal tumors is measured using the epidural spinal cord compression scale (ESCC), also known as the Bilsky score. Whether Bilsky score affects short/long-term outcomes remains unknown. We sought to compare the impact of Bilsky score 0-1 vs. 2-3 with regards to: 1) preoperative presentation, 2) perioperative variables, and 3) long-term outcomes.
Methods: A single-center, retrospective cohort study was undertaken of patients undergoing metastatic spine surgery between 01/2010-01/2021. Multivariate logistic/linear/Cox regression were performed, controlling for age, BMI, race, total decompressed levels, tumor size, other organ metastasis, and postoperative radiotherapy/chemotherapy.
Results: Of 343 patients with extradural spinal metastasis, 92(26.8%) patients presented with Bilsky 0-1 and 251(73.2%) with Bilsky 2-3. Preoperatively: Patients with Bilsky 2-3 were older(p=0.008), presented more frequently with sensory deficits(p=0.029), and had worse preoperative Karnofsky Performance Score(KPS)(p=0.002). Perioperatively: Preoperative/postoperative chemotherapy and radiotherapy were similar between the two groups. However, patients with Bilsky 2-3 had more total decompressed levels(p=0.005) and more transpedicular decompression(p < 0.001), with similar operative time(p=0.071) and EBL(p=0.502), complication rates(p=0.442), and neurological deficit(p=0.852) compared to Bilsky 0-1. Interestingly, patients with Bilsky 2-3 had a longer length of stay(LOS)(p=0.007) with less home discharge(p < 0.001). Long-term: No difference was found in 90-day readmissions(p=0.607), reoperation(p=0.510), LR(p=0.100), and time to LR(log-rank;p=0.532). However, patients with Bilsky 2-3 had significantly worse postoperative KPS(p < 0.001), worse Modified McCormick Scale (MMS)(p=0.003), shorter OS(log-rank;p < 0.001), and worse 1-year survival (p=0.012). Bilsky 2-3 lesions were also associated with shorter OS on univariate and multivariate Cox regression(HR=1.78,95%CI=1.27-2.49,p < 0.001), with no significant impact on time to LR.
Conclusion : Bilsky 2-3 lesions were associated with longer LOS, more non-home discharge, worse postoperative KPS/MMS, shorter OS, and reduced survival at one year, compared to Bilsky 0-1, with no significant difference in short-term outcomes or LR. Higher grade Bilsky score lesions are at a higher risk for worse outcomes, including decreased survival.
