Surgical treatment for internal carotid artery aneurysms requiring strategic selective clipping or parent artery occlusion/flow alteration

In patients with blood blister-like or dissecting aneurysms(Group A) or large-giant aneurysms(Group B) of the internal carotid artery(IC), a surgical strategy may include selective clipping or parent artery occlusion (PAO)such as trapping, blind-alley formation, or flow alteration. Between 2003 and 2012, 25 cases in Group A and 30 cases in Group B were operated on in our institution and their results were retrospectively analyzed. Patients in Group A underwent STA-MCA or high flow bypass followed by trapping of the IC in the acute stage of subarachnoid hemorrhage(SAH), if possible. The bypass was selected in consideration of the collateral flow and the risk of delayed vasospasm. Patients in Group B received clipping or PAO depending on the condition of the perforators and the optic nerve, or wall thickness of the aneurysm, etc. The associating bypass was selected mainly according to the results of a carotid artery test occlusion. In Group A, 60% of the patients were in good recovery at discharge. The most influencing factors on the prognosis included rerupture before surgery(6 cases), primary brain injury(2 cases)and perforator injury(2 cases). Although two thirds of the surgeries were performed in the acute stage, no infarctions due to delayed vasospasm were experienced. In Group B, 93% of the patients were discharged in good recovery. Nineteen cases the ended with clipping showed relatively good results but surgical perforator injury occurred in one patient. In eleven cases that required PAO and bypass, two cases of bypass occlusion that required reconstruction and one case of transient ischemia in the perforator territory were experienced. In Group A patients, prevention of rerupture seems most important. Therefore, a bypass prior to PAO should be selected to supply enough blood flow to overcome the possible delayed spasm and trapping of the IC should be performed with a clip avoiding perforators and other branches as much as possible. In Group B patients in whom the surgical strategy may include selective clipping or PAO, intraoperative decision making of the selection seems important. When PAO and bypass surgery was selected, certainty of the bypass and a method of PAO to avoid perforator injury play a key role. Appropriate application of antithrombotic agents was thought to be important as well.