title: Rotational vertebrobasilar insufficiency due to compression of a persistent first intersegmental vertebral artery variant: case report.
abstract: Rotational vertebrobasilar insufficiency, or bow hunter's syndrome, is a rare cause of posterior circulation ischemia, which, following rotation of the head, results in episodic vertigo, dizziness, nystagmus, or syncope. While typically caused by dynamic occlusion of the vertebral artery in its V2and V3segments, the authors here describe a patient with dynamic occlusion of the vertebral artery secondary to a persistent first intersegmental artery, a rare variant course of the vertebral artery. In this case the vertebral artery coursed under rather than over the posterior arch of the C-1. This patient was also found to have incomplete development of the posterior arch of C-1, as is often seen with this variant. The patient underwent dynamic digital subtraction angiography, which demonstrated occlusion at the variant vertebral artery with head turning. He was then taken for decompression of the vertebral artery through removal of the incomplete arch of C-1 that was causing the dynamic compression. After surgery the patient had a complete resolution of symptoms. In this report, the authors present the details of this case, describe the anatomical variants involved, and provide a discussion regarding the need for atlantoaxial fusion in these patients.
authors.affiliation: Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Vivek P
authors.initials: VP
authors.lastname: Buch
authors.affiliation: Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Madsen
authors.affiliation: Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Kerry A
authors.initials: KA
authors.lastname: Vaughan
authors.affiliation: Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Paul F
authors.initials: PF
authors.lastname: Koch
authors.affiliation: Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: David K
authors.initials: DK
authors.lastname: Kung
authors.affiliation: Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Ali K
authors.initials: AK
authors.lastname: Ozturk
mesh_terms: D000328:Adult; D002533:Cerebral Angiography; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D019299:Decompression, Surgical / Q000379:methods; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D014057:Tomography, X-Ray Computed; D014711:Vertebral Artery / Q000000981:diagnostic imaging; D014715:Vertebrobasilar Insufficiency / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*
keywords: CTA = CT angiography; DSA = digital subtraction angiography; MRA = MR angiography; PFIA = persistent first intersegmental artery; RVBI = rotational vertebrobasilar insufficiency; bow hunter's syndrome; cervical; persistent first intersegmental artery; rotational vertebrobasilar insufficiency; vascular disorders