Perioperative Bioccipital Watershed Strokes in Bilateral Fetal Posterior Cerebral Arteries During Spinal Surgery.

Abstract

Vision loss due to cerebral infarction during spinal surgery is less described. Intraoperative hypotension would be a leading cause. Patients with variation of the circle of Willis could be more prone to present stroke in this context, but reports are lacking to sustain the theory. Bilateral occipital watershed ischemic strokes have never been described before. We report the case of a patient with a fetal origin of both posterior cerebral arteries (PCAs), presenting this particular anatomic stroke following lumbar laminectomy surgery for spinal stenosis during which intraoperative hypotension was observed. We discuss how this common anomaly associated with intraoperative hypotension could have promoted this serious complication. A 55-year-old man woke up with cortical blindness after he had undergone lumbar surgery during which a marked decrease in blood pressure had occurred. Magnetic resonance imaging revealed bilateral symmetric infarctions of the occipital lobes in the distal territory of both PCAs and smaller anterior watershed ischemic strokes, suggesting a hemodynamic mechanism. Extended investigations, including conventional angiography, failed to find any cause of stroke but revealed bilateral fetal PCAs supplied by internal carotid arteries only. Two years later, the patient has not recovered and remains severely visually impaired. The standing hypothesis would be posterior low-flow infarctions resulting from intraoperative hypotension on a variation of the circle of Willis more prone to decrease in cerebral blood flow. Moreover, this case supports the hypothesis of vascular insufficiency due to intraoperative hypotension as cause of stroke during spinal surgery.