gms | German Medical Science

Objective: We report for the first time the feasibility, usefulness, and limitations of the near-infrared (NIR) indocyanine green (ICG) videoangiography applied during surgical procedures of or around the extracranial vertebral artery (VA).

Methods: Ten patients of 2 neurosurgical centres (2 women and 8 men, mean age: 54 years) were evaluated. Procedures in which were applied the NIR-ICG videoangiography were: VA V1 segment rerouting (n=1), VA V1 segment transposition (n=5), and tumors close to the VA V2 (n=1) and V3 (n=3) segments.

Results: The VA V1 segment appeared much brighter than the carotid artery because the VA is relatively clean of adventitia and thinner-walled. Early after ICG injection, the V1 segment became homogenously fluorescent. On the other hand, the fluorescence of the V2 segment was variable depending of the presence or absence of an extrinsic compression. In absence, the V2 segment appeared as non-contiguous hot spots. In presence, the arterial enhancement was homogenous. These results are correlated with the VA anatomy. Contrarily to the V1 segment, a venous plexus surrounds the V2 one. This venous plexus attenuates the fluorescent light. Hot spots correspond to areas where the artery is spontaneously closer to the surface in absence of extrinsic compression and give important information about the accurate position of the VA within the sheath. Homogeneous enhancement in presence of an extrinsic compression is noted because the artery is pushed superficially. At the late phase, the V1 segment signal was attenuated, the venous plexus surrounding the V2 and V3 segments enhanced homogeneously, thereby masking the VA itself, and the vertebral veins draining the vertebral venous plexus were detected below the C6 level.

In all cases of transposition and in the case of rerouting, the NIR-ICG videoangiography confirmed the VA patency. The technique was not useful during the exposure for locating the VA, and thus for posterolateral approaches of nerve sheath tumors in relation with the V3 segment, because the artery was not detectable as long as not exposed.

Conclusions: The use of the NIR-ICG videoangiography during extracranial VA procedures is helpful for providing information about vessel patency and localizing the VA within its periosteal sheath. This technique provides no information during the VA exposure, which therefore remains guided by anatomical landmarks because the VA must be in the field of the infrared camera to be detected.