What is the pathophysiology of vertebrobasilar stroke?

Updated: Aug 09, 2021
  • Author: Vladimir Kaye, MD; Chief Editor: Stephen Kishner, MD, MHA  more...
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The most common vascular condition affecting the vertebrobasilar system is atherosclerosis, in which plaques cause narrowing and occlusion of the large vessels.

The pathology of small vessel disease (affecting arteries 50-200 µm in diameter) is different from that of atherosclerosis, because the small vessels become occluded by a process called lipohyalinosis, which frequently occurs in association with hypertension. Occlusions of these small vessels lead to small, round infarctions called lacunes, which may appear as single lesions or may be distributed as multiple lesions scattered widely throughout the subcortex and brainstem.

Lipohyalinosis weakens the vessel wall, and in hypertensive individuals, rupture of the artery may occur, resulting in a focal hemorrhage. Almost all intracerebral hemorrhages originate from the rupture of these small, penetrating vessels.

Because of the close anatomical relationship between the vertebral arteries and the cervical spine, chiropractic manipulation or neck rotation may traumatize the vertebral arteries in the neck. The damaged arteries may occlude with thrombus or undergo dissection. However, a retrospective study by Whedon et al of patients aged 66-99 years suggested that there is very little risk of vertebrobasilar stroke in association with chiropractic manipulation of the cervical spine. [4]

Embolic occlusion of the vertebrobasilar system is not common and usually is artery-to-artery with occlusion of the basilar artery. Donor sites for the emboli typically are the aortic arch, the subclavian artery, and the origin of the vertebral arteries.

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