Intraoperative Angiography during Cerebral Aneurysm Surgery

Abstract

Intraoperative angiography (IOA) has been considered since the 1960s for use during surgical repair of cerebral aneurysms. The potential of IOA to confirm complete aneurysm occlusion and patency of the parent vasculature intraoperatively are of significant clinical value. Over the past 5 to 7 years, use of intraoperative angiography has been increasing, and many centres now use the technique frequently. However, no consensus exists regarding the routine use of IOA in cerebral aneurysm surgery. Different institutional paradigms include the use of IOA rarely or never, selectively based on aneurysm complexity, or routinely in all aneurysm cases. This article describes the authors’ use of intraoperative angiography with particular emphasis on practical recommendations for implementing an institutional program of routine IOA as an adjunct to all surgeries for aneurysm repair. Recent improvements in radiolucent headholders and retractors, as well as improved digital subtraction angiography using portable fluoroscopy units have enabled the more efficient and practical use of intraoperative angiography. Traditionally, successful aneurysm clipping has been confirmed intraoperatively by inspection of the aneurysm clip and adjacent vasculature, combined with aneurysm puncture to confirm occlusion, prior to the closure of the craniotomy. Intraoperative angiography had historically been reserved for the most complex cases. Between 5.1 and 7.3% of surgically treated aneurysms are unexpectedly incompletely occluded, leading to additional treatment or ongoing risk of rupture [1–5]. Without IOA, the surgeon’s only means to confirm complete aneurysm occlusion is to puncture the aneurysm dome. This is not necessary after ruling out residual filling of clipped aneurysm through intraoperative angiography. An incompletely occluded aneurysm will hemorrhage from the puncture site, which although not usually problematic, is certainly not an optimal means to discover incomplete aneurysm occlusion. Parent vessel occlusion during surgical clipping of a cerebral aneurysm occurs in approximately 3–14% of cases [1–6]. Although rare, parent vessel occlusion can lead to permanent neurological deficit or death. Furthermore, only a small window of time exists to recognize parent vessel occlusion and restore flow before irreversible ischemia of brain parenchyma occurs, and therefore, postoperative investigations demonstrating parent vessel occlusion do not generally lead to successful intervention. IOA can demonstrate parent vessel occlusion in a timely manner, and lead to corrective intervention during the initial craniotomy. Furthermore, IOA alters the aggressiveness required in confirmation of anatomy and inspection of the distal tips of the aneurysm clip. Although rare, complications related to aggressive clip inspection do occur, and can be mitigated by IOA in certain cases. Others studies of cerebral blood flow such as microdoppler auscultation and postoperative R. Kumar J. A. Friedman (&) Department of Surgery, Texas A&M Health Science Center College of Medicine, 3201 University Drive, Suite 425, Bryan-College Station, TX 77802, USA e-mail: jafriedman@medicine.tamhsc.edu