Diluted Calcium Hydroxylapatite for Skin Tightening of the Upper Arms and Abdomen

Background: The collagen-stimulating properties of Radiesse® (calcium hydroxylapatite, CaHA) can be used for skin-tightening procedures by hyper-diluting the product with lidocaine or saline.

Objective: To evaluate the effectiveness and safety of diluted CaHA for skin tightening in two case series of women with skin laxity in the upper arms or abdomen.

Methods: For each case series, 10 female subjects were enrolled. In the upper arms, CaHA diluted 1:2 with normal saline solution and 2% lidocaine was injected subdermally using a short, linear-threading technique. Skin elasticity was assessed at baseline and Months 1 and 3 using a cutometer. In the abdominal wall, CaHA diluted 1:4 with saline solution was injected subdermally using a linear-threading technique. Subjects underwent pre- and post-treatment (70 days) ultrasound scans to determine dermal thickness around the umbilicus and sides of the abdomen. Subjects and physicians assessed treatment outcomes using the 5-point Global Aesthetic Improvement Scale (GAIS). Adverse events and tolerability were recorded.

Results: Cutometry results for upper arm skin showed an increase in skin elasticity from 72 U at baseline to 82 U at Month 3 (P≤0.05). Ultrasound measures of the abdominal wall demonstrated statistically significant increases in dermal thickness after injection of diluted CaHA of 0.7 mm (umbilicus) and 0.4 mm (sides of abdomen). Diluted CaHA resulted in an overall increase in dermal thickness of 26.7% (P≤0.05). In both case series, 90% of subjects and physicians rated treatment outcomes on GAIS as much or very much improved. Treatment was well tolerated.

Conclusions: Diluted CaHA improved skin elasticity and increased dermal thickness in the upper arms and abdomen after only a single treatment. The procedures were well tolerated, and subject and investigator satisfaction with treatment results was very high. Injection of diluted CaHA is an effective procedure for skin tightening in the upper arms and abdomen. <p><em>J Drugs Dermatol. 2017;16(9):900-906.</em></p>.