Injectable techniques and management of nodules

Objectives: In order to optimize skin quality injection with hyaluronic acid, avoiding adverse events and to achieve optimal placement, specific techniques, including needle depth, angles, volume and spacing will be discussed. Delayed onset nodules from HA skin quality injections have been reported. Etiology and management of nodules will be discussed. Introduction: Skin quality improvement by placing low G prime hyaluronic acid in the dermis or subdermis is a growing trend in medical aesthetics. Despite manufacturer initiated protocols, the presentation will discuss a modified approach based on in vivo high resolution ultrasound imaging. Materials / method: A popular skin quality hyaluronic acid product (VYC-12L, Allergan) was used to study the post injection placement of the product. All injections were performed by 32G 13mm needle. Various droplet volumes (0.01, 0.02, 0.03, 0.04 and 0.05 ml) were placed at the deep dermis level. High resolution ultrasound (Clarius HD3 L20, 20 MHz) imaging was obtained immediately post injection. Results: At 0.01 ml volume, all product stayed within the deep dermis. At 0.02 ml volume, majority of the product stayed within the deep dermis with some products "leaking" down to the subdermal plane. At 0.03 ml volume, about half of the products leaked down to the subdermal plane. 1.2 cm wide distribution. At 0.04 ml volume, majority of the products leaked into the subdermal plane. 1.7 cm wide distribution. At 0.05 ml volume, almost all the products are placed in the subdermal plane. 2 cm wide distribution. Conclusion: From the ultrasound study, there is no doubt that skin quality HA injection will end up in the subdermal plane unless the volume was limited to 0.01 ml. A 0.01 ml injection volume would be very impractical as the spacing would have to be less than 4 mm apart. At 0.05 ml, the spacing can be 1-1.2 cm apart but the distribution or coverage would be heterogenous. Based on this study, the author is recommending a 0.03 ml injection (realistically with a manual injection by hand, the volume could be 0.25-0.035 ml). The spacing should be approximately 0.75 cm between injection sites.