Abstract
Most popular fillers in cosmetic medicine are hyaluronic acid based. These comprise over 90% of the market and come with the advantage to be soluble in case of complications. Other fillers are contained in the group of bio-stimulatory fillers. They exert a secondary volumizing effect by provoking a low-grade inflammatory response that produces extra collagen. Examples are calcium-hydroxyapatite and L-poly-lactid acid. Finally autologous fat is being used as a filling substance (lipofilling). The gravest complications with fillers are intravascular injections. In particular when injected in arteries fillers can block blood flow and lead to skin necrosis or vison loss in case the material occludes the Central Retinal Artery (CRAO). Two opposing theories about the nature of arterial occlusion exist. One based on Ian Taylor idea of choke anastomoses assume vasoconstriction induced by the filler, both of the primary offended artery and its anastomosing vasosomes. In this case resolving the hyaluronic acid filler with the enzyme hyaluronidase at the primary occluding location would suffice. This is done under ultrasound guidance. The other theory assumes displacement of parts of the filler to end arterioles. Then, the whole affected area has to be flooded with large dosages of hyaluronidase. Obstructions with fillers based on other materials cannot be resolved. It seems logical to prevent intra-arterial filler injection by duplex sonography detection of the course of arteries prior to injection. Ultrasound has additional advantages for cosmetic doctors such as recognizing remains of previously injected filler. It also can give feedback on a physician’s ability to inject filler in the correct subdermal location.