The Spinal Instability Neoplastic Score (SINS) as a Surgical Decision-Making Tool for the Treatment of Spine Metastasis

ABSTRACT

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To investigate the potential clinical use of the spinal instability neoplastic score (SINS) for determining the surgical strategy, especially regarding the need for anterior support. SUMMARY OF LITERATURE REVIEW: The SINS seems to enable an improved qualitative and quantitative assessment of spinal instability in patients with spinal metastasis. MATERIALS AND METHODS: We retrospectively reviewed 69 consecutive patients who underwent surgical treatment for spinal metastasis. We assessed the patients' preoperative status with respect to each component of the SINS. Multiple logistic regression was performed to calculate odds ratios (ORs) representing the associations among SINS, age, Eastern Cooperative Oncology Group performance status, modified Tokuhashi score, as well as the preoperative Nurick grade variables and reconstruction of the anterior spinal column. RESULTS: Among the 6 items in the SINS, those indicating the degree of collapse and alignment had significantly higher scores in those who underwent corpectomy and anterior support (p<0.001). Multiple logistic regression revealed that the total SINS was the only factor significantly associated with predicting whether anterior support should be performed (adjusted OR=1.595). Receiver operating characteristic (ROC) curve analysis suggested that a cut-off value of 10 points on the SINS scale could be used to decide whether anterior support following corpectomy should be performed (AUC=0.706). CONCLUSIONS: The SINS, insofar as it assesses the degree of collapse and alignment, is a potentially useful tool for determining the surgical strategy in patients with spinal metastasis, especially for deciding upon the necessity of additional anterior support procedures.