Microscope-integrated near-infrared indocyanine green videoangiography during surgery of intracranial aneurysms: the Helsinki experience

BackgroundMicroscope-integrated near-infrared indocyanine green videoangiography (ICG-VA) is a new method of intraoperative blood flow assessment. The objective of this study was to evaluate the reliability of this technique in the evaluation of neck residuals and patency of branches after microneurosurgical clipping of intracranial aneurysms (IAs).MethodsDuring a period of 14 months, between November 2005 and December 2006, 289 patients with intracranial aneurysms were operated on in our institution. Intraoperative ICG-VA was performed during microneurosurgical clipping of 239 IAs in 190 patients. Postoperative computed tomography and computed tomography angiography (CTA) were performed for all patients. Intraoperative interpretation of ICG-VA in assessing the neck residual or the patency of vessels after clipping of each single aneurysm were recorded and correlated with postoperative CTA and/or digital subtraction angiography.ResultsPostoperative imaging studies revealed no incomplete occlusions of aneurysm domes. Unexpected neck residuals were observed in 14 aneurysms (6%). There were no parent artery occlusions. Unexpected branch occlusions including both major and minor branching arteries were observed in 15 aneurysms (6%).ConclusionsIndocyanine green videoangiograph is a simple and fast method of blood flow assessment with acceptable reliability. Indocyanine green videoangiograph can provide real-time information to assess blood flow in vessels of different size as well as the occlusion of the aneurysm. Intraoperative assessment of blood flow in the perforating branches is one of the most important advantages. In selected cases such as giant, complex, and deep-sited aneurysms or when the quality of image in ICG-VA is not adequate, other methods of intraoperative blood flow assessment should be considered.