Far Lateral Approach With C1 Hemilaminotomy for Excision of a Ruptured Fusiform Lateral Spinal Artery Aneurysm: 2-Dimensional Operative Video.

Abstract

The lateral spinal artery (LSA) represents the most rostral extent of the posterolateral arterial axis of the spinal cord and supplies both the posterior and lateral aspects of the spinal cord.1 The LSA originates from either the intradural segment of vertebral artery or the lateral segment of the posterior inferior cerebellar artery.1,2 It terminates at the level of C5 because it anastomoses with the posterior spinal artery. Although the LSA is in communication with the subarachnoid space, subarachnoid hemorrhage (SAH) due to an LSA aneurysm is rare.3-6 Moreover, accurate diagnosis of vascular pathologies involving the LSA is challenging because the LSA is typically too small to be visualized with conventional angiography.2 Here, we present the case of a 74-year-old woman who presented to our institution with headache, nausea, and confusion due to posterior fossa SAH without any visible vascular malformation on initial diagnostic cerebral angiography. A right frontal external ventricular drain was placed for communicating hydrocephalus. Immediate cerebral angiogram was within normal limits. Two-week follow-up angiogram demonstrated a fusiform right LSA aneurysm. The endovascular treatment was not an option because of the risk of occlusion of proximal perforators of the right posterior spinal artery, resulting in a long segment ischemia. The patient underwent a right far lateral transcondylar approach with C1 hemilaminotomy and excision of the LSA aneurysm. The postoperative course was uneventful. The patient was neurologically intact. Six-month follow-up angiogram showed no evidence of residual aneurysm. LSA pathologies should be kept in mind with posterior fossa SAH. Surgical excision is an effective treatment option in carefully selected patients. The patient consented to the procedure.