Vertebral artery stenosis

Vertebral artery stenosis can occur anywhere inside or outside the skull, and lesions caused by vertebral artery stenosis are very common. Because the situation is rather complicated, we can have a general understanding of it, as it involves more professional knowledge. If there are any questions, it is best to communicate with the doctor based on the patient's condition, provide treatment as much as possible, and strive for a good prognosis.

Vertebral artery stenosis can occur anywhere inside or outside the brain and accounts for 20% of posterior circulation ischemic strokes. Stenotic lesions, especially at the origin of the vertebral artery, are not uncommon.

Nearly one quarter of ischemic strokes involve the posterior or vertebrobasilar circulation. Vertebral artery stenosis can occur anywhere inside or outside the brain and accounts for 20% of posterior circulation ischemic strokes. Stenotic lesions, especially at the origin of the vertebral artery, are not uncommon. An angiographic study of 4748 patients with ischemic stroke found that 18% on the right side and 22.3% on the left side had varying degrees of stenosis in the proximal extracranial vertebral artery; this was the second most common site after stenosis of the internal carotid artery (ICA) at the carotid bifurcation. The above-mentioned stenoses can now be treated using endovascular technology.

In sharp contrast to carotid artery stenosis, little attention has been paid to the targeted treatment of vertebral artery stenosis, and experience is clearly insufficient. This, to some extent, reflects the difficulty in obtaining imaging data of the vertebral artery, which in turn restricts the implementation of targeted treatment. However, recent advances in imaging techniques and the advent of vertebral artery angioplasty have provided new opportunities for the treatment of this disease.

Principle: The vertebral artery arises from the posterior and superior part of the first segment of the subclavian artery. The left vertebral artery arises directly from the aortic arch in 6%. The branches of the vertebral artery are not always direct continuations of the parent common carotid artery like the internal carotid artery, but almost always arise at right angles to the donor vessel. The vertebral artery has a diameter of 3 to 5 mm, which is a very small blood vessel compared to the subclavian artery. Therefore, only a small amount of the normal blood flow in the subclavian artery enters the vertebral artery. This anatomical difference can well explain the differences in hemodynamics between the carotid cerebral circulation and the vertebral basilar cerebral circulation, as well as the different tendencies to form different types of atherosclerotic plaques. Atherosclerotic lesions in the vertebral arteries are usually "smooth" and rarely ulcerate due to secondary thrombosis. The morphological differences between carotid and vertebral artery atherosclerotic plaques are mainly seen on angiography and are supported by only a few published pathological data.

principle

The vertebral artery can be divided into three extracranial segments and one intracranial segment anatomically. The first section is from the origin of the vertebral artery to the transverse foramen of the 5th and 6th cervical vertebrae. The second segment always runs in the intervertebral foramen before reaching the third segment located below the atlas; after the third segment leaves the intervertebral foramen, the head end faces the capitate foramen. The final segment, the intracranial segment, penetrates the dura mater and arachnoid membrane at the base of the skull and terminates at the medullary-pontine junction to join the contralateral vertebral artery to form the midline basilar artery. The extracranial segment of the vertebral artery gives off small spinal branches to the periosteum and vertebral body, and muscular branches to the deep surrounding muscle area. The short intracranial segment gives off important anterior and posterior spinal arteries to the medulla oblongata and spinal cord, and small perforating blood vessels to the medulla oblongata; its largest branch, the posterior inferior cerebellar artery (PICA), is responsible for the blood supply to a small part of the medulla oblongata on the snout and cerebellum. When PICA branches are occasionally absent, collateral vessels are responsible for supplying the lateral medulla oblongata. After the vertebral artery enters the skull, the wall of the artery undergoes significant changes, the adventitia and intima become thinner, and the elastic fibers in the elastic layers of the intima and adventitia decrease.

Among healthy people, 15% have obstructed unilateral vertebral artery (diameter < 2 mm), and its contribution to basilar artery blood flow is quite small. A smaller degree of asymmetry is also common, with the left vertebral artery being dominant in 50% of cases, the right side in 25%, and only the remaining 1/4 having symmetrical blood flow on both sides. These variants are of limited or no clinical significance unless there is concomitant stenosis of the vertebral artery origin or the proximal subclavian artery.