Medial Loop of V2 Segment of Vertebral Artery Causing Compression of Proximal Cervical Root

Abstract

ObjectiveIt is rare that the medial loop in the V2 segment of the vertebral artery (VA) causes compression of the proximal cervical root of the spinal cord without leading to bony erosion and an enlarged foramen. We evaluated the clinical significance and incidence of the medial loop in the V2 segment of the VA.MethodsWe reviewed the records from 1000 consecutive patients who had undergone magnetic resonance imaging evaluation of the cervical spine between January 2005 and January 2008. The inclusion criteria were that over a third of the axial aspect of the VA located in the intervertebral foramen was inside the line between the most ventral points of the bilateral lateral mass, and that the ipsilateral proximal root deviated dorsally because of the medial loop of the VA. We excluded cases of bone erosion, a widened foramen at the medial loop of the VA, any bony abnormalities, tumors displacing VA, or vertebral fractures. The medical records were reviewed retrospectively to search for factors of clinical significance.ResultsIn six patients (0.6%), the VA formed a medial loop that caused compression of the proximal cervical root. One of these patients had the cervical radiculopathy that developed after minor trauma but the others did not present with cervical radiculopathy related to the medial loop of the VA.ConclusionThe medial loop of the VA might have a direct effect on cervical radiculopathy. Therefore, this feature should be of critical consideration in preoperative planning and during surgery.

The diagnosis and management of a vertebral artery loop causing cervical radiculopathy

“…The vertebral artery, originating from the subclavian, passes through the transverse foramina of the C2-C6 vertebrae in the cervical spine, and is referred to as the V2 segment in this region [1]. The limited space for the artery to traverse may result in anomalies or vascular abnormalities causing either compression of the artery (with symptoms of vertebrobasilar insufficiency) or compression of the cervical nerve roots (resulting in pain or radicular symptoms) [2].…”

“…The limited space for the artery to traverse may result in anomalies or vascular abnormalities causing either compression of the artery (with symptoms of vertebrobasilar insufficiency) or compression of the cervical nerve roots (resulting in pain or radicular symptoms) [2]. An anomalous V2 segment may present as a tortuous vertebral artery; a medial location of the vertebral artery or an abnormal vertebral artery entrance [1]. Hadley was the first to report a tortuous vertebral artery loop with bony erosions in the cervical vertebrae of four out of 21 cadavers [3].…”

“…Hadley was the first to report a tortuous vertebral artery loop with bony erosions in the cervical vertebrae of four out of 21 cadavers [3]. and reported an incidence of 0.6% [1]. In contrast, Curylo et al in a cadaveric study reported an incidence of 2.7% in 222 specimens [5].…”

“…Several reported cases of vertebral artery loop formation were successfully managed conservatively [1]. This may include non-steroidal anti-inflammatory treatment, physiotherapy and or injection therapy as required [6,13].…”

Risks for Vascular Injury During Anterior Cervical Spine Surgery

“…Reports 10,11 regarding the prevalence and anatomical features of patients with those medial loop of arteries based on magnetic resonance angiography (MRA) suggested that only a few patients showed higher anatomical risk for VAI in ACDFs. The relationship between arteries and bone or uncovertebral joint to which surgeons pay most attention to during the decompression procedure is, however, unclear based on MRA.…”