Blindness After Facial Filler Injections: The Role of Extravascular Hyaluronidase on Intravascular Hyaluronic Acid Embolism in the Rabbit Experimental Model.

Abstract

Blindness caused by ophthalmic artery embolism is the most catastrophic complication of facial hyaluronic acid (HA) injections. Extravascular (retrobulbar) injection of hyaluronidase has been suggested as a salvage in this calamitous situation. However, the effectiveness of this treatment still lacks consensus. The aim of this study was to investigate the role of extravascular hyaluronidase in dissolving intravascular HA occlusion. Two different animal experiments were performed: (1) isolated rabbit abdominal aorta segments filled with HA were treated with extravascular immersion of highly concentrated hyaluronidase for 90 minutes, followed by gross observation, microscopic examination, particle size analysis, and immunohistochemical staining; and (2) live rabbit auricular arteries were first occluded with HA and then immediately treated with extravascular injection of hyaluronidase. The ears were then evaluated by gross observation, microscopic examination, and perfusion studies after 60 minutes and again after 90 minutes. The HA within the aorta segments showed no gross or microscopic changes after treatment with extravascular hyaluronidase. Hyaluronidase could only be detected in adventitia of the aortae, instead of in vascular smooth muscle, tunica intima, or vascular lumen. The occluded auricular arteries showed no reperfusion after extravascular injection of hyaluronidase. In this rabbit model, extravascular hyaluronidase was unable to penetrate into the arterial lumen of the isolated abdominal aorta or the live auricular artery of the rabbit to dissolve intravascular HA within a 90-minute time limit, thus casting doubt on whether extravascular (retrobulbar) hyaluronidase injection has a role in treating ophthalmic artery embolism caused by HA injections.