Background
Acne during youth can leave permanent facial scarring. The depressed acne scars can be treated by injection of stabilized hyaluronic acid (S‐HA) into the dermis. Due to the large number of acne scars, manual injection methods are technically difficult, and bear high risk of lump formation in the dermis. Therefore, the author designed a specific injection method to solve the two abovementioned problems.
Materials/Methods
102 Patients who suffered from acne scars were treated with a mixture of S‐HA (Restylane Vital®) and abobotulinumtoxinA (Dysport®). Using an automatic injector, microdroplets of the mixture (0.001cc of S‐HA and 0.125 U abobotulinumtoxinA) were delivered into 1000 intradermal sites on whole face except eyelids. This instrument radically reduced injection amounts per site (0.001cc), lessened manual operator efforts, and ensured consistent injection depth (from 0.8mm to 1.2mm depending on individual dermal thickness) into the facial dermis. The changes in each depression site of acne scars were evaluated by topographical computer analysis (point‐roughness), based on the 40 magnification microscopic photos generated. Depth measurements of each small acne scar point were taken one by one at the exact same point before and after the treatments. Global Aesthetic Improvement Scale (GAIS) was measured for improvement of acne scars at 1 and 6 months post‐treatment. Additionally, serial histologic examinations of the biopsy specimens evaluated neocollagenesis, neoelastinogenesis, and longevity state of the S‐HA.
Results
78 patients showed improvements of depressed acne scars in physical examinations, medical photos, and dermascopic photos.
Using topographic computer analysis, the average point‐roughness decreased 27.48 % (at 1‐month) from 29.042±6.85 (baseline) to 21.05±6.30 µm (P
