gms | German Medical Science

Objective: Today, ICG angioangrpahy is an accepted adjunct in microsurgical aneurysm treatment. ICG angiography is used to detect vessel compromise by the clip, aneurysm residuals after clipping (“dog ear”) or persistent aneurysm filling due to incomplete clipping. For ICG angiography the microscope must be in a direct line-of-sight with the region of interest, limiting especially the identification of compromise of hidden arteries and hidden dog ears. For the first time, we used a prototype endoscope for visualization of ICG fluorescence in hidden regions of the microsurgical field and evaluated its potential usefulness.

Method: By selection of a filter and use of a special light source, a switch from the normal endoscopic image to endoscopic ICG angiography is possible. 10 patients with aneurysms of the anterior circulation underwent microsurgical clipping. Prior and after microsurgical clip application, microscopic and endoscopic ICG angiography was performed. The information gained by microscopic ICG angiography was compared with that of endoscopic ICG angiography.

Results: Endoscopic ICG angiography was technically feasible in all 10 patients. Its usefulness depends on the location, size and geometry of the aneurysm. In 6 patients endoscopic ICG angiography does not provide the neurosurgeon with more information than microscopic ICG angiography. In 4 patients, endoscopic ICG angiography confirmed uncompromised blood flow in microscopically hidden vessels. In 1 patient a dog ear was only detected by endoscopic ICG angiography. For persistent aneurysm filling (n=1), ICG angiography seems dispensable, as the same information was obtained already by microscopic ICG angiography.

Conclusions: In selected cases of aneurysm clipping, endoscopic ICG angiography provides the neurosurgeon with informations that are not obtainable by direct microscopic visualization and microscopic ICG angiography. Endoscopic ICG angiography could be an additional useful adjunct in aneurysm surgery and has the potential to further improve the operative results.