Flow Arrest for Complex Intracranial Aneurysm Surgery by Using Adenosine

The term complex intracranial aneurysms (CIAs) refers to aneurysm at a narrow and difficult location, difficult shape, and also giant size (aneurysm that is bigger than 25 mm in diameter) [1]. Giant aneurysms are more likely to bleed and present as subarachnoid hemorrhage, or sometimes they become partly thrombosed with ischemic brain causing mass effect with progressive symptoms or even death. Microsurgery and clip ligation can be challenging in CIAs because it is very difficult to have a panoramic view of the aneurysm, where sometimes the parent vessel is laid beneath the aneurysm, difficult to identify all branches and perforators, and also the surgical corridor could be very deep and narrow and surrounded by important neurovascular structures. During the clipping, it is important to make sure the aneurysm is well clipped to prevent injury from any perforator (Figs. 27.1, 27.2, and 27.3). Flow arrest can be induced by using adenosine; it will briefly reduce cerebral perfusion pressure and the tension on aneurysm, thereby facilitating the clip ligation. The length of time for the flow arrest will provide the surgeon to work at the aneurysm and the parts surrounding it or even reduce the bleed if it was ruptured during dissection. It will provide the time interval for the surgeon to be able to secure the neck of the aneurysm. The adenosine is working by inducing the transient asystole for a few minutes.