Quantifying Depth of Injection of Hyaluronic Acid in the Dermis: Data from Clinical, Laboratory, and Ultrasound Settings.

Although manufacturers' instructions for use of dermal fillers ordinarily direct injection in the superficial, mid or deep dermis, or, in some cases, the hypodermis (subcutis), the precise depth of injection may not always be for injectors. In this article, investigators report findings gathered from histopathology, ultrasound, "live" one on one training injections, as well as application of a mathematical formula for depth calculation of the various layers within the dermis. Areas of particular interest are the superficial reticular dermis and the mid dermis. Following the depth measurements detailed by Della Volpe et al in 2012, investigators compare and contrast their own depth findings of the various layers, arriving at the conclusion that the depth of the dermis is not as deep as had been previously assumed. The investigators also develop an argument for the appropriate angles of injection for placement of dermal filler into the various layers, demonstrating that the heretofore widely used angles of 30˚ and 45˚ are far more acute than required.