Abstract
Purpose :
Advancements in the use of indocyanine green (ICG) imaging devices have allowed for intricate detailing of periorbital anatomy including vascularization of extraocular muscles (EOMs). Knowledge of vascularization of EOMs has relied upon cadaveric dissection in the past, however the use of ICG may help to further identify vascular structures in vivo allowing for detailed, real-time planning in periorbital surgery.
Methods :
An IRB-approved prospective study was conducted on participants undergoing enucleation surgery from 2021 - 2022. Intraoperatively, 5.0 mg of ICG was given intravenously to visualize intraoperative blood flow to the rectus muscles once the globe was removed. Fluorescence was captured by the SPY PHI System (Stryker, Kalamazoo, MI) or EleVision IR Platform (Medtronic, Minneapolis, MN). Two oculoplastic surgeons were independently instructed to count the number of anterior ciliary arteries vascularizing each rectus muscle. The readers were presented with cropped, zoomed-in recordings to mask them from which rectus muscle they were analyzing. Inter-rater reliability was subsequently calculated.
Results :
Eight participants were included in this study with a mean age of 56 (range 33-80 years old) and the majority male (75%). When assessing individual extraocular muscles, the average number of anterior ciliary arteries of the rectus muscle was noted: superior rectus 1.6, inferior rectus 1.6, medial rectus 1.6, and lateral rectus 1.4. Inter-rater reliability when looking at individual extraocular muscles was as follows: superior rectus 78%, inferior rectus 63%, medial rectus 71% and lateral rectus 83%.
Conclusions :
Intraoperative ICG may be a reliable method to visualize the EOM vascularization. Larger studies are needed to see the how the accuracy of ICG fluorescence of EOMs compares to prior cadaveric studies. Future uses of ICG fluorescence intraoperatively may help identify cases of EOM ischemia during orbital surgery.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.