The modern management of
intracranial aneurysms includes both constructive and deconstructive strategies to eliminate the
aneurysm from the circulation. Both microsurgical and
endovascular techniques are used to achieve this goal. Although most
aneurysms can be eliminated from the circulation with simple
clip reconstruction and/or coil insertion, some require revascularization techniques to enhance tolerance of temporary
arterial occlusion during clipping of the
aneurysm neck or to enable proximal occlusion or trapping. In fact, the importance of revascularization techniques has grown because of the need for complex reconstructions when endovascular
therapies fail. Moreover, the safety and feasibility of bypass have progressed due to advances in
neuroanesthesia, technological innovations, and ~ 5 decades of accumulating wisdom by bypass practitioners.
Cerebral revascularization strategies become necessary in select patients who possess challenging vascular
aneurysms due to size, shape, location, intramural
thrombus,
atherosclerotic plaques,
aneurysm type (for example,
dissecting aneurysms), vessels arising from the dome, or poor collateral vascularization when parent artery or branch occlusion is required. These techniques are used to prevent
cerebral ischemia and subsequent clinical sequelae. Bypass techniques should be considered in cases in which balloon test occlusion demonstrates inadequate cerebral blood flow and in which there is a need for Hunterian
ligation, trapping, or prolonged temporary occlusion. This review article will focus on decision making in bypass surgery for complex
aneurysms. Specifically, the authors will review graft options, the utility of balloon test occlusion in decision making, and bypass strategies for various
aneurysm types.