Lumps, bumps, Tyndall effect, and contour abnormalities can occur after dermal fillers. Necrosis is another unwelcome event. But central retinal artery occlusion (CRAO) after dermal filler injections is the most devastating complication that has been reported several times after injections in multiple areas of the face, including the glabellar region, nose, nasolabial fold and temples.
This phenomenon happens when an embolus finds its way into the central retinal artery. The reported cases involve large boluses injected very quickly. The force of extrusion creates pressure that overcomes the mean arterial pressure, so that particles achieve retrograde flow. When the finger is released from the plunger, the thought is the embolus then rapidly takes an anterograde path into the central retinal artery. It is well known that the retina only has 60 to 90 minutes for survival in a non-perfused state. It is also known that an embolus in the central retinal artery is difficult, if not impossible to release or dissolve.
There have been no proven methods to treat CRAO secondary to dermal filler in vivo, but cadaveric and animal studies have been performed, which will hopefully lead to promising results.
In the case of necrosis, also likely a result of embolism, injection of hyaluronidase is very effective. We know that this enzyme dissolves the product and provides very quick results within 24 hours. Hyaluronidase comes as Vitrase (200 u/mL), a bovine form, or Hylenex (150 u/mL), a human recombinant form. It is paramount that injectors of dermal fillers carry a “crash cart” that is easily accessible in case complications arise. The most important item on this cart should be hyaluronidase, and several unexpired vials should be available.
If necrosis or a CRAO should occur, flood the area with non-diluted hyaluronidase. As much as 450 units can be injected into the area ever hour until perfusion is seen again. In the case of lumps or bumps, or if contouring is requested, the hyaluronidase can be diluted with 4 cc of saline and injected in small aliquots.