Exploring the Possibility of a Retrograde Embolism Pathway from the Facial Artery to the Ophthalmic Artery System In Vivo

Background Blindness caused by soft tissue fillers is an extremely low-probability event, but it results in great concern because of its devastating consequences. Currently, the mechanism of an embolism is usually considered to be an accidental injection of fillers into the blood vessels of the face, such as a facial artery, and then retrograding into the ophthalmic artery system, which causes retinal ischemic necrosis. In addition, previous studies have shown that there are anastomoses between facial arteries and branches of the ophthalmic artery in cadavers. An in vivo study, however, has not yet been reported. Methods This study was approved by the institutional review board of Xijing Hospital, Fourth Military Medical University. Under general anesthesia, we dissected the same side of the face and eyeball in rabbits to manifest the facial artery and retina separately. Later, a needle (27 g) connected to a syringe (10 ml) full of methylene blue was inserted into a rabbit facial artery. Then, after poking a tiny hole in the central retinal artery, methylene blue was injected into the facial artery as quickly as possible (0.5 ml per second). At the same time, we carefully observed whether the central retinal artery had dye spillover or staining in the sclera. If blue dye was observed in the eye ground and/or the sclera, then it was thought to have entered the ophthalmic artery system (a positive result). In contrast, if none of the blue dye was observed, it was considered a negative result. A Chi-square ( χ 2 ) test with a fourfold table was used to compare the differences in the frequencies of blue dye observed between living and dead rabbits. A value of p