Kimmerle anomaly as a cause of extravasal compression of the vertebral artery

Abstract

Kimmerle anomaly, also known as ponticulus posticus, is a commonly known variant of the atlas anatomy. It occurs as a result of complete or incomplete ossification of the posterior atlanto-occipital membrane over the groove of the vertebral artery, which leads to the formation of an arcuate foramina containing the vertebral artery and the posterior branch of the C1 spinal nerve. This anatomical variation is associated with symptoms of vertebrobasilar insufficiency, various types of headache, visual impairment, photopsia, syncope, drowsiness, reduced work capacity, unsteady gait, sleep disturbance, panic attacks.
Objective of the article is to highlight the attention of physicians on the widespread and not well understood Kimmerle anomaly, which is the cause of ischemic disorders in the vertebrobasilar circulation due to extravasal compression of the vertebral arteries.
In the case of signs of impaired blood flow in the vertebrobasilar circulation, an X-ray of the cervical spine has to be done. In case of Kimmerle anomaly, ultrasound of neck vessels and transcranial doppler with functional tests should be performed. In the case of significant influence of disorder on the vertebrobasilar circulation, computed tomography with angiography is mandatory. If the patient's large vertebral artery is compressed, indications for surgical decompression of the vertebral artery at the level of the atlas is indicated. In cases of mild symptoms of cerebral vertebrobasilar circulation, symptomatic medication, wearing a Chance collar, physical therapy, and regimen restrictions are prescribed.