Introduction: The Spinal Instability Neoplastic Score (SINS) is utilized to identify patients with metastatic cancer who are likely to benefit from spinal stabilization. Traditionally, patients who are regarded as unstable are the most likely candidates for surgical intervention. This study looked specifically at the outcomes following surgery for SINS stable and unstable patients.
Methods: Patients from a single academic health system were reviewed over a five-year period. One hundred and two patients were identified with metastatic disease and eighty-five patients had preoperative imaging available for SINS scoring. Mortality data was collected from a database of death certificates with a minimum one-year follow up for all patients. Univariate and multivariate survival analyses were performed via Cox Proportional Hazards regression. Chi-squared and Student t-tests were utilized as univariate statistical tests of categorical and continuous data, respectively.
Results: Sixty patients were classified as “SINS stable” (or potentially unstable; SINS = 12) and twenty-five patients were classified as “SINS unstable” (SINS = 13). Demographics were comparable (SINS stable: 62 years, 57% male; SINS unstable: 60 years, 48% male; p’s > 0.5). Sixty percent of SINS stable patients died, with a mean time from surgery to death of 228 days while 72% of SINS unstable patients died, with an average time from surgery to death of 108 days. Mortality within 30 days was higher for SINS unstable patients (31.5%) as compared to the SINS stable patients (5.2%, p = 0.009). Unstable SINS score was a significant predictor of time to death (Hazard Ratio (HR) = 1.13, p = 0.007)
Conclusions: Our results suggest that spine instability as measured by SINS parameters may have predictive value for early mortality and overall survival. The authors acknowledge that this data set reflects a small patient sample size, and the difference in mean survival after surgery varied for patients in this study.
Patient Care: We believe that patients should have earlier surgical evaluation; as SINS unable patients may undergo surgery too late.
Learning Objectives: By the conclusion of this session, participants should be able to 1) describe the importance of the SINS score in identifying patients who may benefit from surgery, 2) discuss, in small groups how unstable SINS score may predict early mortality and 3) identify an effective treatment for metastatic spine disease