Assessing chiasm perfusion and postoperative visual function with superior hypophyseal artery indocyanine green angiograms during endoscopic endonasal surgery

To date, there are no validated intraoperative tools to predict postoperative visual function following endoscopic endonasal surgery (EES). Assessment of post-surgical vision during surgery can help in postoperative planning and disposition and inform surgical decisions in real-time. The objective of this study was to evaluate the capability of intraoperative endoscopic indocyanine green (ICG) angiography to measure optic chiasm perfusion and determine its relationship with postoperative visual function.

A retrospective review was performed on patients undergoing EES for sellar and suprasellar lesions. ICG was injected prior to surgical closure at a time when the optic chiasm and anterior circulation were visible. Luminescence of the superior hypophyseal artery (SHA) branches enveloping the optic chiasm was registered 10 seconds after ICG penetration into the anterior cerebral arteries (ACAs). Pre and post-operative visual acuity and field exams were used to assess visual function. Patients with and without new deficits were compared to examine statistical association with intraoperative ICG findings.

Twenty patients were included (mean age 49 years, 55% female). Eighteen patients displayed stable or improved vision after resection and demonstrated luminescence of all chiasmatic branches within 10 s of ACA fluorescence. Two patients experienced new postoperative visual deficits. Upon review, their ICG administrations showed no fluorescence of the SHA branches enveloping the chiasm. A lack of chiasm fluorescence within ten seconds of ACA fluorescence was associated with new postoperative vision deficits (p = 0.005).

This study shows that the lack of ICG fluorescence of SHA branches at the chiasm correlates with ischemic changes and new post-operative bitemporal hemianopsia. Lack of chiasm fluorescence after 10 seconds of observation reflects compromised chiasm perfusion and likely new post-surgical visual deficits.