Symptomatic vertebral artery loop: a case report and review of literature.

Vertebral artery loop formation is a rare anatomical variant capable of causing bony erosion, encroachment on cervical neural foramen, neurovascular compression, or vertebrobasilar insufficiency. Health professionals should keep the diagnosis of vertebral artery loop formation in mind, especially when the plain radiograph of the cervical spine shows enlargement of the intervertebral foramen. If overlooked, serious complications like vertebral artery injury may occur during surgery or vertebrobasilar angiography, as well as cerebrovascular stroke during transforaminal cervical epidural steroid injections.