In the mid-1960s, some modern microsurgeons led by Yasargil used the intracranial and extracranial vascular bypass to treat ischemic cerebrovascular disease, and began the history of modern microvascular surgery. At present, vascular bypass technology for the treatment of ischemic diseases, as well as large and complex intracranial aneurysms, has become an effective technical method and has been recognized by the academic community.

Like cerebral vascular bypass surgery, cerebral vascular occlusion can be achieved by artificial methods, connecting extracranial blood vessels and intracranial blood vessels through transplanted blood vessels such as saphenous vein, radial artery, superficial temporal artery and other intracranial blood vessels. This will rebuild the blood supply.

Vascular bypass therapy for aneurysms, mostly in replacement vascular bypass (Replacement bypass), directly reconstructs blood flow, including:

(1) direct bypass: commonly used superficial temporal artery or occipital artery and the middle cerebral artery branch or the posterior inferior cerebellar artery directly anastomosis;

(2) Transplantation bypass: mainly with radial artery or saphenous vein graft, with the external carotid artery as the blood supply artery and the intracranial trunk blood vessel;

(3) In situ bypass: a fusiform or wide-necked aneurysm that cannot be directly clipped in the skull, directly resecting the distal artery to the proximal artery or the distal artery to the adjacent artery. To prevent arterial ischemia in the distal aneurysm.

(4) Reimplantation or interposion graft: When the aneurysm lesions are removed and cannot be bridged in situ, the extracranial matching vessels are transplanted to remove the proximal and distal ends of the diseased vessels to restore blood flow.

Cerebrovascular bypass surgery is differentiated according to the blood flow after the bypass. The low-flow vascular bypass has a blood flow of less than 50 ml/min, and mainly uses the superficial temporal artery or the occipital artery for the middle cerebral artery M3 segment, the superior cerebellar artery, the posterior cerebral artery, and the bridging of the posterior inferior cerebellum. High-flow vascular bypass for blood flow greater than 50 ml / min, mainly with saphenous vein and radial artery, used for vascular bypass after carotid artery, vertebral artery and basilar artery occlusion. The radial artery is easy to take, and the blood flow is 50~150ml/min. The diameter of the vein from the upper part of the lower leg to the lower part of the thigh is relatively consistent. This part of the vein is the preferred material for blood collection. The venous blood flow of this section is 100~200ml/min.

Cerebrovascular bypass surgery has been used in patients with severe cerebral vascular stenosis, patients with repeated ischemic attacks, patients with moyamoya disease, and patients with large intracranial aortic aneurysms. Cerebrovascular bypass surgery is more difficult and risky than coronary artery bypass grafting, especially for the elderly with obvious arteriosclerosis. However, cerebral vascular bypass surgery has provided a way to treat some diseases that were previously incurable and have been well treated.

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