Adenosine-Assisted Clipping of Intracranial Aneurysms

Abstract

technically demanding procedure and requires adaptive skills that greatly vary based on the features of each unique aneurysm. Depending on the location of the aneurysm, a neurosurgeon may be faced with challenges including accessing difficult locations through narrow operative corridors, maneuvering around vital neurologic structures, and manipulating fragile tissues. One of the important challenges and potential complications during aneurysm clipping is intraoperative aneurysm rupture (IAR).1 This can be daunting especially when it occurs before adequate dissection and exposure of vessel(s) essential for proximal and distal control. Uncontrolled bleeding further obscures the surgical field and hurried maneuvers of an unprepared surgeon increase the risk of neurologic damage. Therefore, it is crucial that a variety of tools and strategies exist for use during intracranial aneurysm clipping to combat any potential challenges that may arise. Although a variety of techniques exist to reduce blood flow to and through the aneurysm during dissection and clipping, temporary arterial occlusion via placement of temporary clips on the parent vessels is the most reliable.2,3 Placement, however, can be challenging if the rupture occurs early or if the anatomy does not facilitate complete trapping. Prolonged temporary clip placement also increases ischemic risks.4 Rarely, temporary clips can result in vasospasm of the parent arteries.3,4 An alternative to temporary clipping is systemic flow arrest through the IV administration of adenosine. Adenosine administered as a bolus transiently slows sinus rate and atrioventricular (AV) nodal conduction resulting in brief asystole.5 Spontaneous return of sinus rhythm occurs within seconds as this naturally occurring nucleoside is transported into cells and rapidly deaminated. Significant hypotension from vasodilation often occurs after asystole and return of circulation.