Ischemic Stroke Secondary to Dynamic Vertebral Artery Stenosis: Case Report and Review of the Literature

Abstract

Ischemic stroke secondary to dynamic vertebral artery stenosis or occlusion, also known as "bow hunter's syndrome," is a rare stroke mechanism. We report a case of a 24-year-old man with multiple hereditary exostosis (MHE) diagnosed at childhood. His first presentation to a neurologist was due to neck pain and clinical syndrome suggestive of ischemia in the vertebrobasilar territory. A therapeutic occlusion was done successfully without complication. The patient was discharged two days later on aspirin alone. In follow up one year later he continued to be symptom free. Moreover, this stroke mechanism has been reported extensively in the literature in isolation or secondary to many underlying diseases. In total, there are 168 cases reported in the published English literature, in either case reports or small series. In this review, we found that by far, vertebral artery occlusion at the atlanto-axial (C1-2) level dominated most reported cases. The most frequent presentation that led to further investigation was syncope or pre-syncope provoked by head rotation to one side. To our knowledge, there is no previous report of any stroke syndrome related to MHE before our case. In this paper, we report the first case secondary to MHE and review the literature up to date since the first reported case in 1952.

Cerebellar Ischemic Stroke Secondary to Rotational Non-Dominant Vertebral Artery Occlusion (RVAO): A Rare Complication Following Supratentorial Surgery

“…A complete stroke workup was then performed, including a CT angiography with 3-dimensional reconstruction that ruled out any significant vascular occlusion, but only a right hypoplastic VA (►Figs. 2,3). Moreover, bone window reconstruction of the cervical spine did not reveal any presence of focal stenoses or foraminal osteophytes.…”

“…According to a recent literature review, 2 the most common site of VA dynamic occlusion was the C1-C2 level, followed by the craniocervical junction and the lower subaxial cervical vertebrae. Regarding treatment strategies, conservative management with antiplatelets was the most reported option, even though neck immobilization, endovascular treatment, cervical decompression, and cervical fusion have been described as well, the latter with a relatively favorable outcome.…”

“…The clinical impact that a transient occlusion of a vertebral artery can cause, ranges from a totally asymptomatic condition to clinically relevant ischemic stroke within the affected vascular territory (2.4% of cases). 2 Besides clinical suspicion, imaging diagnostic tools include magnetic resonance angiography (MRI angiography), computed tomography angiography (CT angiography), ultrasonography, and catheter angiography. Treatment is usually conservative—neck immobilization, aspirin—with an overall good prognosis.…”

“…Treatment is usually conservative—neck immobilization, aspirin—with an overall good prognosis. 2 When visible on MRI, the ischemic zone usually appears to be located at the level of the lower portions of one cerebellar hemisphere, in a predominantly mesial region, as per the involvement of the terminal vascular territory of the posterior inferior cerebellar artery (PICA).…”

“…Because the syndrome's first reports, many etiological mechanisms have been described over the years. 2 3 4 However, to date, there are no previous reports of RVAO related to head rotation during patient positioning for neurosurgical procedures.…”