Evaluation of surgical microscope-integrated intraoperative near-infrared indocyanine green videoangiography during aneurysm surgery

The goals of surgical treatment of intracranial aneurysms are to occlude the lesion and maintain blood flow in parent, branching and perforating vessels. We report our experience in 3 cases using this method for intraoperative blood flow assessment, detection of incomplete clipping of aneurysm and to assess image quality and evaluate the clinical value of this method. A special arrangement of the filters was designed to allow the passage of near-infrared light required for the excitation of the indocyanine green (ICG) fluorescence (700 - 850 nm) from a modified microscope light source into the surgical field and the passage of ICG fluorescence (780 - 950 nm) from the surgical field back into the optical path of the surgical microscope (Cart Zeiss, Oberkochen, Germany). Thus, the ICG angiography could be completely performed with a surgical microscope. The reported 3 cases, one female and 2 male, either with incomplete or inadvertent clipping of the branching vessels of unruptured aneurysms were performed using ICG which was excellent in detection of incomplete or inadvertent clipping of the branching vessels.