SPLASH: Split-Body Randomized Clinical Trial of Poly- l -Lactic Acid for Adipogenesis and Volumization of the Hip Dell.

Background: Injectable poly- l -lactic acid (PLLA-SCA) increases extracellular matrix to improve skin quality. The hip dell is an underappreciated element of gluteal aesthetics. Adipose tissue has roles in aesthetics and skin functioning.

Objective: To investigate the efficacy of PLLA-SCA treatment to induce adipogenesis and volumize the hip dell.

Materials and methods: This was a double-blinded, split-body trial of 15 women with hip dell volume deficits. Each subject was randomized to have 1 hip dell treated with 150 mg of PLLA-SCA while the contralateral hip dell received the equivalent volume of saline. Subjects received 3 treatments at 1-month intervals and were followed for 9 months. Assessments included physician global aesthetic improvement scale, ultrasonography, and histologic examination.

Results: Blinded investigators rated PLLA-SCA-treated hip dells as improved and much improved. The dermis and adipose layers increased in thickness by 26.1% and 27%. These measures, in addition to collagen and elastic fiber quality, were significantly improved compared with saline-treated hip dells, which did not change from baseline. Subject satisfaction was also significantly greater on the PLLA-SCA-treated side. No subject experienced significant adverse effects.

Conclusion: Poly- l -lactic acid is a safe and effective method for durable volumization and aesthetic improvement of the hip dell. PLLA-SCA may promote adipogenesis and elastogenesis.