Neurologic Complications of Preoperative Embolization of Spinal Metastasis: A Systemic Review of the Literature Identifying Distinct Mechanisms of Injury

Background: Preoperative embolization of spinal metastases may improve outcomes of resection by reducing surgical blood loss and operative time. Neurologic complications are rarely reported and the mechanisms leading to injury are poorly described. Methods: We present 2 illustrative cases of embolization-related neurologic injury from distinct mechanisms and the findings of a systemic literature review of similar complications according to the PRISMA guidelines. Results: A 77-year-old man with a history of renal cell carcinoma presented with gait dyscoordination and arm pain/weakness. Magnetic resonance imaging showed a C7/T1 mass causing severe compression of the C7/T1 roots and spinal cord. After embolization and tumor resection/fusion, lethargy prompted imaging showing multiple posterior circulation infarcts believed to be secondary to reflux of embolic particles. A 75-year-old man with renal cell carcinoma presented with L1 level metastasis causing conus compression and experienced paraplegia after superselective particle embolization presumed to be secondary to flow disruption of the artery of Adamkiewicz. Analysis of the literature yielded 6 articles reporting instances of cranial infarction/ischemia occurring in 10 patients, 12 articles reporting spinal cord ischemia/infarction occurring in 17 patients, and 5 articles reporting symptomatic postembolization tumoral swelling in 5 patients. Conclusions: Neurologic injury is a risk of preoperative embolization of spinal metastasis from either compromise of spinal cord vascular supply or cranial stroke from reflux of embolic particles. Postprocedural tumor swelling rarely leads to clinical deficit. Awareness of these complications and the presumed mechanisms of injury may aid clinicians in implementing interventions and in counseling patients before treatment.