A Scoring System for Outpatient Orthopedist to Preliminarily Distinguish Spinal Metastasis from Spinal Tuberculosis: A Retrospective Analysis of 141 Patients

OBJECTIVE: Spinal tuberculosis (TB) misdiagnosed of spinal metastasis was not rarely reported, especially in outpatients department. This study was aimed to establish an outpatient scoring system to preliminarily distinguish spinal metastasis from spinal TB. METHODS: We retrospectively reviewed consecutive 141 patients with a pathological diagnosis of spinal metastasis (82 cases) or spinal TB (59 cases) in our hospital from January 2017 to June 2018. The following clinical characteristics which can be obtained by outpatient orthopedist were recorded and analyzed: age, gender, malignant tumor history, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and imaging features including distribution characteristics of vertebral lesions, subligamentous spread, paravertebral or psoas abscess, involved vertebral element, intervertebral disc, and sequestra formation. The prevalence of clinical characteristics in spinal metastasis was evaluated, and the scoring system was established using logistic regression analysis. The performance of the scoring system was also prospectively validated. RESULTS: The outpatient scoring system was based on five clinical characteristics confirmed as significant predictors of spinal metastasis, namely, malignant tumor history, subligamentous spread, posterior element lesions, preserved discs, and no sequestra formation. Spinal metastasis showed a significant higher score than spinal TB (8.17 points vs. 1.97 points, t = 18.621, P < 0.001), and the optimal cut-off value for the scoring system was 5 points. The sensitivity and specificity of the scoring system for predicting spinal metastasis were 97.85% and 88.33%, respectively, in the validation set. CONCLUSION: Spinal lesions with the score of 5 to 10 would be considered a diagnosis of spinal metastasis, while the score of 0 to 4 may be spinal TB. Because the scoring system is mainly based on the clinical characteristics that can be obtained by an outpatient orthopedist, it is suitable to be used as a diagnostic tool in the outpatient department.