Over a 19-year period, 7 cases of complex ACA aneurysm were treated with bypasses and reviewed retrospectively. The bypasses were classified into 4 groups according to donor blood flow: internal carotid artery-ACA, external carotid artery-ACA, communicating bypass, and reconstruction bypass of the ipsilateral postcommunicating ACA.
The cases included 1 precommunicating aneurysm, 3 communicating aneurysms, 2 postcommunicating aneurysms, and 1 double aneurysm (communicating and postcommunicating). The types of bypass included 1 internal carotid artery-ACA, 6 communicating bypasses, 3 external carotid artery-ACAs, and 2 reconstruction bypass of the postcommunicating ACA. Postoperative modified Rankin Scale scores were 0 (6 cases) and 3 (1 case of a communicating aneurysm with complicated memory disturbance because of infarction). One case revealed asymptomatic infarction.
Surgical treatment of complex ACA aneurysms requires knowledge of a variety of bypass techniques. Although the type of bypass should be selected according to patient-specific anatomy and the neurosurgeon’s preference, the new classification of bypass-specified ACA aneurysms may alter the way surgeons think about ACA bypasses, and in combination with the concept of the protective bypass, can be used to establish a comprehensive algorithm for each type of complex ACA aneurysm.