The Sins Scale in the Evaluation of Stability in Patients With Spinal Metastasis

Abstract

Objective To evaluate the distribution of patients seen in the emergency care unit of the Instituto do Câncer do Estado de São Paulo in the categories “stable”, “indeterminate” and “unstable” as classified by the SINS scale. Methods The medical charts of patients treated between May and September 2013 were reviewed. Patients with a diagnosis of spinal metastasis were analyzed and data on age, sex, primary tumor location, neurological status, and the presence and intensity of pain at rest and in movement were obtained. The SINS criteria were used to evaluate the radiological involvement of the spine. Results We included 81 patients with a mean age of 59.57 years; 32 (39.51%) men and 49 (60.49%) women. Breast (19.75%), prostate (18.52%) and lung (17.28%) were the most common primary tumor sites. Only 18 patients (22.22%) had a single lesion and 51 (62.96%) had 3 or more metastatic lesions. Of the total, 56 (69.14%) were of undetermined stability, 19 were stable (23.46%) and 6 were unstable (7.41%). Twenty-two (27.2%) presented neurological deficit in the physical examination. None of the patients with severe deficit, Frankel A or B, were stable according to the SINS classification. All unstable lesions presented with kyphotic and/or scoliotic deviation (p <0.001). Most patients with undetermined lesions (78.6%) and all patients with unstable lesions had mechanical pain (p = 0.001). Conclusion In this case series, there was a high rate of patients classified by the SINS scale as of undetermined instability (69.14%). There was a high number of patients with multiple metastases (62.96%), which was not considered a modifier of the SINS instability criteria and which needs to be the focus of future studies. Level of evidence IV; Case Series.