Evaluation der Durchblutung des Sehnervs in Echzeit mit ICG-Angiographie und intraoperativen VEPs während Schädelbasiseingriffen

Any mass lesion around the optic apparatus can result in visual impairment by direct optic nerve compression, causing ischemia or demyelination. Improvement of visual function after tumor removal may be related to a change in the blood supply to the optic nerve (ON), which might be seen in the pial circulation during surgery. Our study aims to evaluate the effectiveness, reproducibility, and safety of using intraoperative ICG-angiography as a predictive factor for postoperative visual outcomes as well as preservation of vision.

Ten Patients with different perichiasmatic pathologies were selected for this analysis. Each patient completed image studies utilizing enhanced MRI, CT, ophthalmological examination, and ioVEP. Three control patients were selected assuming normal pial support of the ON in a patient who underwent an aneurysmal clipping for an ICA aneurysm. ICG was administered intraoperatively at 0,2mg/kg through peripheral vein access following a rapid of injection 10ml Nacl 0,9% before and after tumor resection using software for flow analysis ( means of flow 800 software, Kinevo, Carl Zeiss Co). The intervals between the first appearance of ICG in the internal carotid artery (ICA) and pial circulation of the ON to full saturation of both were measured at each pre-and postresection state.

Ten patients (4 male, 6 female) were included. All patients showed improvement in visual outcomes postoperatively. Prolonged VEP latency was observed in all patients intraoperatively. The mean prolonged latency of P100 was 0.31±1.01 ms and 3.81±1.98 ms for the right and left eyes respectively, more on the tumor side. Peak time differences of ICA-ON before tumor resection was 2.77±2.65ms and 2.9±2.33ms after tumor resection (r=0.863, p>0.05, paired samples test). Mean time improvement of ON to ICA was 0.0389±1.34 ms. There was no time difference between the peak of the optic nerve and the internal carotid artery in our control.

Flow 800 seems to make a reproducible measurement to evaluate not only the real time perfusion of the optic nerve but also could provide information about improvement of blood circulation. iVEP, on the other hand, tends to prolong latency even if the optic nerve is not involved by a pathology, directly. Further studies are needed to evaluate the significance of the intraoperative flow changes.