Surgical clipping
Aneurysms can be treated by clipping the base of the aneurysm with a specially-designed clip. Whilst this is typically carried out by craniotomy, a new endoscopic endonasal approach is being trialled. Surgical clipping was introduced by Walter Dandy of the Johns Hopkins Hospital in 1937. After clipping, a catheter angiogram or CTA can be performed to confirm complete clipping. Endovascular coiling
Endovascular coiling refers to the insertion of platinum coils into the aneurysm. A catheter is inserted into a blood vessel, typically the femoral artery, and passed through blood vessels into the cerebral circulation and the aneurysm. Coils are pushed into the aneurysm, or released into the blood stream ahead of the aneurysm. Upon depositing within the aneurysm, the coils expand and initiate a thrombotic reaction within the aneurysm. If successful, this prevents further bleeding from the aneurysm. In the case of broad-based aneurysms, a stent may be passed first into the parent artery to serve as a scaffold for the coils. Cerebral bypass surgery
Cerebral bypass surgery was developed in the 1960s in Switzerland by Gazi Yasargil. When a patient has an aneurysm involving a blood vessel or a tumor at the base of the skull wrapping around a blood vessel, surgeons eliminate the problem vessel by replacing it with an artery from another part of the body. Prognosis
Outcomes depend on the size of the aneurysm. Small aneurysms (less than 7 mm) have a low risk of rupture and increase in size slowly.
Vasospasm
Vasospasm, referring to blood vessel constriction, can occur secondary to subarachnoid hemorrhage following a ruptured aneurysm. This is most likely to occur within 21 days and is seen radiologically within 60% of such patients. The vasospasm is thought to be secondary to the apoptosis of inflammatory cells such as macrophages and neutrophils that become trapped in the subarachnoid space. These cells initially invade the subarachnoid space from the circulation in order to phagocytose the hemorrhaged red blood cells. Following apoptosis, it is thought there is a massive degranulation of vasoconstrictors, including endothelins and free radicals, that cause the vasospasm. Risk factors
Intracranial aneurysms may result from diseases acquired during life, or from genetic conditions. Hypertension, smoking, alcoholism, and obesity are associated with the development of brain aneurysms. Cocaine use has also been associated with the development of intracranial aneurysms.Other acquired associations with intracranial aneurysms include head trauma and infections. Genetic associations
Coarctation of the aorta is also a known risk factor, as is arteriovenous malformation. Genetic conditions associated with connective tissue disease may also be associated with the development of aneurysms. This includes:
autosomal dominant polycystic kidney disease,
neurofibromatosis type I,
Marfan syndrome,
multiple endocrine neoplasia type I,
pseudoxanthoma elasticum,
hereditary hemorrhagic telangiectasia and
Ehlers-Danlos syndrome types II and IV.Specific genes have also had reported association with the development of intracranial aneurysms, including perlecan, elastin, collagen type 1 A2, endothelial nitric oxide synthase, endothelin receptor A and cyclin dependent kinase inhibitor. Recently, several genetic loci have been identified as relevant to the development of intracranial aneurysms. These include 1p34–36, 2p14–15, 7q11, 11q25, and 19q13.1–13.3.