Factors Affecting Prognosis of Patients With Osteoblastoma of the Mobile Spine: A Long-Term Follow-up Study of 70 Patients in a Single Center

Abstract BACKGROUND Osteoblastoma (OBL) in the mobile spine is a benign tumor with aggressive potential. There is not much published information on OBL of the mobile spine as a result of rarity of the disease. There are controversies over the aggressive subtype and prognostic factors of the condition. OBJECTIVE To explore the aggressive subtype and investigate prognostic factors of OBLs in the mobile spine. METHODS A retrospective analysis of spinal OBL was performed by survival analysis. Patients in 2 cohorts were analyzed based on the Enneking grade and pathological evaluation. Local recurrence-free survival (RFS) was estimated using the Kaplan–Meier method to identify potential prognostic factors. Factors with P ≤ .05 were subjected to multivariate analysis by Cox regression analysis. P ≤ .05 were considered statistically significant. RESULTS Included in this study were 70 patients with spinal OBL who were followed up by a mean of 67.1 mo (range 24-188). Local recurrence was detected in 9 cases after initial surgery, and death occurred in 2 cases. The result of statistical analysis suggested that Epithelioid OBL (EO) with Enneking stage 3 (St.3) and total spondylectomy were independent prognostic factors for RFS. CONCLUSION St.3 or EO lesions seem to be more aggressive than St.2 or conventional osteoblastomas, but St.3 and EO should be considered simultaneously in predicting the aggressiveness of the lesion and the risk of recurrence. Total spondylectomy performed either by en bloc or piecemeal could significantly reduce recurrence of OBLs in the mobile spine.