Surgery and Interventional Radiology

The most desirable treatment for subarachnoid hemorrhage is early surgery to clip the aneurysm and prevent further bleeding. Intracranial clipping of an unruptured aneurysm is curative and can usually be done with very low morbidity. After an aneurysm has ruptured, the timing of surgery is important for patient outcome. Past practice had been to wait approximately 2 weeks after the SAH before surgery, based on the premise that the patient was a better surgical candidate once cerebral edema had subsided and he/she was medically stabilized. However, a delay of 2 weeks spans the peak times for two of the most dangerous complications of SAH - rebleeding and vasopasm. As a result of several multicenter studies to determine the optimum time of surgery, there has been a definite trend toward surgery within 48 to 72 hours of SAH for patients in Hunt and Hess clinical grades I and II and, in some situations, grade III. Patients in grades IV and V are treated medically for potential future surgery at a later date. Surgery is usually not performed at all in the presence of coma or severe neurological deficits due to the low recovery and high mortality rate.

Early surgery has many benefits, including reducing the possibility of rebleeding, allowing for removal of clots that may cause vasospasm, and treating vasospasm aggressively without the risk of rebleeding. Microsurgical techniques and improvements in anesthesia offer new options for better surgical outcomes. The surgical approach and method of aneurysmal obliteration depends on the location and characteristics of the aneurysm. An aneurysm with a stem or neck, such as a berry aneurysm, is usually managed with surgical clip. For aneurysms that are difficult to reach, the surgeon may have to modify a clip to fit the specific vessel involved. Before a permanent clip is in place, a temporary clip is applied to assess the effect of clipping on the brain's blood supply. Some aneurysms, such as fusiform aneurysms, are not amenable to clipping because of their shape or location. If the aneurysm cannot be clipped, it may be surgically wrapped in muslin or another type of cloth that provides support to the weakened arterial wall.

Relatively new non-surgical options for the management of cerebral aneurysms now exist. Aneurysm embolization with detachable balloons or coils is possible utilizing microcatheters that can enter vessels previously inaccessible. Generally, patients selected for these options are poor surgical candidates. Such patients have aneurysms that are anatomically unclippable or that are located in accessible areas.

The Guglielmi Detachable Coil (GDC) system is approved for endovascular occlusion in patients with high surgical risk intracranial aneurysms and other neurovascular abnormalities. The coils are a platinum-tungsten alloy and come in a number of sizes and styles. Each coil is attached to a stainless steel delivery wire and is passed through a catheter into the lesion. When the each coil is in place an electric current is applied to the delivery wire. The current dissolves the exposed stainless delivery wire by electrolysis, releasing the coil. Coils are inserted until the lesion is filled. It is believed that the coils function by slowing the flow of blood which allows the formation of a thrombus and reduces pulsation.

The intravascular balloon may be used to occlude either the aneurysm or the parent vessel supplying the area of the aneurysm. A catheter is inserted into the femoral artery and advanced to the aneurysm. Once in place, the balloon is inflated within the aneurysm by means of a liquid polymerizing agent that solidifies and hardens within the balloon. The parent vessel that supplies blood to the area of the aneurysm may also be occluded using this method. Before occluding the parent vessel, it is important to establish whether the vessel can be permanently occluded without producing serious neurological impairment. Complications of intravascular balloon therapy include rupture of the aneurysm, hemorrhage, vasospasms, cerebral ischemia, or cerebral infarction leading to a stroke syndrome.