gms | German Medical Science

Objective: Indocyanine green has recently been explored for intraoperative fluorescence angiography in vascular neurosurgery. Sodium fluorescein is used routinely for retinal angiography. Since the emission peak of fluorescence (490nm) is within the wavelength visible with the filter combinations employed for fluorescence-guided glioma surgery with ALA (>455nm), we wanted to know whether fluorescein angiography of intracranial vessels would give useful and direct inraoperative information during vascular neurosurgery without the necessity of image processing.

Methods: Using a standard NC4 Zeiss microscope modified for ALA-fluorescence-guided glioma surgery, 10 patients with cerebral aneurysms were examined. A 5ml bolus of sodium fluorescein (10%, Alcon) was administered intravenously. Aneurysma filling, patency of parent vessels and of perforators were visually assessed using the fluorescence mode of the microscope and recorded electronically.

Results: In all cases parent vessels and small perforators were excellently visualized in a real-time fashion after fluorescein administration. Fluorescence-intensity was strong enough to enable direct inspection and manipulation of vessels during surgery with the unaided eye. Even parenchymal vessels in the submillimeter range were clearly highlighted.

Conclusions: Fluorescein angiography using a standard surgical microscope equipped for ALA-fluorescence-guided glioma surgery is highly feasible and provides a simple tool for neurosurgeons that already have this technical modality integrated into their microscopes. The ability to observe the vessels without intervening image processing has the distinct advantage of allowing direct vessel identification and manipulation.