Topographic computer analysis for acne scar treatment on face accompanying biopsy study after dermal injection of hydrotoxin mixture

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. AIMS: This research aims to assess the effect of the intradermal injection of S‐HA and aboborulinumtoxinA mixture in the treatment of all types of acne scars. MATERIALS/METHODS: A total of 102 patients who suffered from acne scars were treated with a mixture of S‐HA (Restylane Vital®) and abobotulinumtoxinA (Dysport(®)). Using an automatic injector, micro‐droplets of the mixture (0.001 cc 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 (0.001 cc), lessened manual operator efforts, and ensured consistent injection depth (from 0.8 to 1.2 mm depending on individual dermal thickness) into the facial dermis. The changes in each depression site of acne scars were evaluated by topographic computer analysis (point roughness), based on the 40 magnification microscopic photographs 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‐month posttreatment. Additionally, serial histologic examinations of the biopsy specimens evaluated neocollagenesis, neoelastinogenesis, and longevity state of the S‐HA. RESULTS: A total of 78 patients showed improvements of depressed acne scars in physical examinations, medical photographs, and dermascopic photographs. 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 < .0001), corresponding with scar improvements observed in physical examinations, and 3.02 ± 0.66 of GAIS at 1‐month posttreatment. Using an injector allowed the hydrotoxin mixture into the deep dermal layer. Biopsy study proved that the injection depth was exactly in the dermis, and showed evidence of neocollagenesis and neoelastinogenesis. Also, the S‐HA particles remained after 1 year, which proved its longevity of at least 1 year. CONCLUSION: The topographic computer analysis using point roughness showed improvement of all subtype acne scars at 1‐month posttreatment. The improvement may have resulted from dermal expansion due to the neocollagenesis and neoelastinogenesis. S‐HA lasted more than 1 year in human dermis.