Abstract
A case of occlusion at the higher cervical level of the carotid artery with a homolateral persistent primitive hypoglossal artery was reported.
A 72 year-old male was admitted because of progressive consciousness disturbance with left side hemiplegia. CT findings, recorded the day after the incident, revealed a marked shift of the midline structure from the right to the left, compression of the right lateral ventricle and a larger low density area over the right cerebral hemisphere. These findings suggested ischemia due to occlusion of the main trunk of a cerebral artery such as the internal carotid artery. Angiograms showed that the internal carotid artery diverged from the common carotid artery at the level of the third cervical vertebral body, and then an aberrant artery branched at the level of the first cervical vertebral body, in an upward and posterior direction. The internal carotid artery was obstructed at a point immediately after divergence from the aberrant artery. This aberrant artery went in the cephalad direction and continued to the basilar artery. The right vertebral artery could not be observed by retrograde brachial angiography but the left artery was hypoplastic. The aberrant artery, which diverged from the right internal carotid artery, was thought to be a persistent primitive hypoglossal artery judging from its characteristic figure.
It is well known that the most common site of arterial stenosis or obstruction of the extracranial portion of the internal carotid artery ranges within 1.5cm distal from its origin. Therefore, the obstructive site of this case was very uncommon, and no previous case reports of a case like this could be found in the literature. The authors supposed the causes of this higher cervical obstruction to be as follows: as at other arterial bifurcations, turbulence and eddy blood stream, which differs from ordinary laminar flow, had crippled the smooth endothelium, and atheromatous deposition was caused at the subendothelial layer. Then arterial stenosis, caused by thickening of arterial wall, and ultimately total occlusion of the internal carotid artery had occured. Following the same process, it was presumed that occlusion of the higher cervical internal carotid artery, immediately after it diverged from the persistent primitive hypoglossal artery, had occured.
