Progressive Tetraparesis in a 57-Year-Old Man With Congenital Absence of an Anterior Spinal Artery: A Case of Anterior Spinal Cord Infarction

A 57-year-old man presented with sudden neck pain radiating down his arms. This pain progressed to bilateral upper and subsequently lower extremity weakness and numbness. His vitals were notable for systolic blood pressures lower than his baseline (down to 90 mm Hg). The patient's neurological examination as well as magnetic resonance imaging of the cervical and thoracic spine localized to a lesion in the anterior spinal cord. The differential diagnosis for such an acute presentation included stroke, demyelination, intramedullary neoplasm, infection, metabolic myelopathy, and a dural arteriovenous fistula. Further imaging with angiography demonstrated that our patient lacked an anterior spinal artery. In its place, collateral flow from cervical artery branches provided sustenance to the anterior spinal cord. In the setting of hemodynamic instability, this variant anatomy likely predisposed the patient to ischemia, leading to the classic presentation of anterior cord syndrome.