gms | German Medical Science

Objective: Indocyanine green (ICG) angiography is used to detect vessel compromise by the clip, residual aneurysms after clipping 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 hidden arteries and dog-ear remnants. In this study, we used a prototype endoscope for visualization of ICG fluorescence in hidden regions of the microsurgical field and evaluated its potential usefulness in comparison to microscopic ICG angiography (m-ICG-A) in a consecutive series of 25 patients.

Method: In selected cases prior and routinely after microsurgical clip application, m-ICG-A and endoscopic ICG angiographies (e-ICG-A) were performed. The information gained by m-ICG-A was compared with that of e-ICG-A.

Results: E-ICG-A was technically feasible in all operations. Intra-arterial fluorescence could be visualized up to 5 times longer with the endoscope than with the microscope. The endoscope allowed a closer view on the fluorescent artery-aneurysm-complex. E-ICG-A provided more information than m-ICG-A in 9 operations: In 4 cases, unhindered blood flow in microscopically hidden vessels (2 cases of perforating arteries, 1 case of A2-segment, 1 case of posterior communicating artery) was confirmed. In 3 cases, a neck remnant was identified. In one case, the neck of the clipped aneurysm could be seen and in one case the endoscopic view allowed visualizing two aneurysms consecutively due to the prolonged fluorescence. In 16 operations, identical information was obtained and in one operation e-ICG-A was inferior because of trapped intra-aneurysmal fluorescence.

Conclusions: In selected cases, e-ICG-A provides the neurosurgeon with information that cannot be obtained by m-ICG-A. E-ICG-A is capable to emerge as a useful adjunct in aneurysm surgery and has the potential to further improve operative results.