Aneurysmal bone cyst of the spine in adult patients: A systematic review and comparison of primary vs secondary lesions

Background: Spine aneurysmal bone cysts (ABCs) rarely occur in adults. Primary and secondary lesions may show some differences and require appropriate treatments. Objective: To systematically review the literature on adult spine ABCs. Methods: PubMed, EMBASE, Scopus, and Web-of-Science were searched. Clinical-radiological features, treatments, and outcomes were analyzed and compared between primary vs secondary adult spine ABCs. Results: We included 80 studies comprising 220 patients. Primary spine ABCs were more frequent (76.4%). Main symptoms were lower-back-pain (42.8%) and motor deficits (31.2%). Tumors were mostly thoracic (31.4%) or cervical (26.8%), showing lytic (70.4%) and/or cystic (52.3%) appearances. Surgical resection (79.1%) was preferred over biopsy (20.9%). Most primary ABCs underwent curettage with bone grafting (62.1%) and laminectomy (39.1%) (P < 0.001), while most secondary ABCs underwent corpectomy (51%) and spine fixation (93.9%) (P < 0.001). Radiotherapy was delivered in 58 patients (26.4%), and embolization in 37 (16.8%). Symptomatic improvement was reported in 91.8% cases, with no differences based on etiology nor extent-of-resection. Median follow-up was 28.5 months, significantly superior in secondary ABCs. Secondary ABCs had significantly higher rates of tumor recurrence (19.2%; P = 0.011) and death (5.8%; P = 0.002). Conclusion: Surgical resection, radiotherapy, and embolization are effective in managing adult spine ABCs. Secondary tumors have worse prognoses requiring more aggressive treatments.