Intradural Extramedullary Spinal Metastases from Non-neurogenic Primary Tumors: A Systematic Review

Background/Aim: Intradural extramedullary spinal metastases (IESMs) may severely affect quality-of-life of oncological patients. Several treatments are available but their impact on prognosis is unclear. We systematically reviewed the literature on IESMs of non-neurogenic origin. Materials and Methods: PubMed, Ovid EMBASE, Scopus, and Web-of-Science were screened to include articles reporting patients with IESMs from non-neurogenic primary tumors. Clinico-radiological presentation, treatments, and outcomes were analyzed. Results: We included 51 articles encompassing 130 patients of a median age of 62 years (range=32-91 years). The most common primary neoplasms were pulmonary (26.2%), renal (20%), and breast (13.8%) carcinomas. Median time interval from primary tumor to IESMs was 18 months (range=0-240 months). The most common symptoms were sensory (58.3%) and motor (54.2%) deficits. Acute cauda equina syndrome was reported in 29 patients (37.7%). Lesions were diagnosed at magnetic resonance imaging (93.3%), myelography (25%), or computed tomography (16.7%). All patients underwent decompressive laminectomy with tumor resection, partial (54.6%) more frequently than complete (43.1%). Adjuvant radiation (67.5%) and/or systemic (13.3%) therapies were administered. After treatment, most patients had symptom improvement (70.8%) and optimal radiological response (64.2%). Four patients experienced IESMs recurrences (3.1%) with median local tumor control of 14.5 months (range=0.1-36 months). Deaths occurred in 50% of patients, with median overall survival of 6.7 months (range=0.1-108 months). Conclusion: Patients with IESMs have significant tumor burden with poor prognoses. Resection and locoregional radiation may offer favorable clinico-radiological responses but are limited in achieving optimal local control and survival.