Effects of Injection Depth and Volume of Stabilized Hyaluronic Acid in Human Dermis on Skin Texture, Hydration, and Thickness

ABSTRACT

BACKGROUND: Stabilized hyaluronic acid (S-HA) is used for soft tissue augmentation and can also be used for dermal hydration. According to previous reports, the injection volume of each shot is more than 0.02 cc for dermal hydration. Clinically, this is an excessive amount for this purpose, so I will introduce a modified method using particle type S-HA injection for dermal hydration. METHODS: One hundred fifty patients who had 1,000 injections of 1 cc S-HA by injector were analyzed. The patients were examined after 1, 2, 6, 12, and 24 months. Changes in skin texture were determined with regard to skin roughness and morphology, dermal hydration by electric resistance, dermal thickness by ultrasonic imaging, and biopsy. An intra-individual study was also performed to compare changes in skin texture between dermal and subdermal injections. RESULTS: Skin roughness significantly improved after this procedure. Electric resistance also decreased. The dermis of the face and hand were thickened about 4% after dermal injection. The injection depth was confirmed by biopsy. There were no significant changes in dermal thickness after subdermal injection with S-HA, which merely replaced fluid volume. Injections into the dermis changed both skin texture and thickness. CONCLUSIONS: Skin texture was improved after 1000 dermal injections (0.001 cc each) of particle type S-HA. Deeper injections only replaced the fluid volume and could not improve skin texture. For this purpose, the use of an injector or mesogun is recommended.