Macrolane for volume restoration and contouring of the buttocks: magnetic resonance imaging study on localization and degradation.

BACKGROUND: Macrolane is a biocompatible, biodegradable, injectable stabilized hyaluronic acid-based gel of nonanimal origin manufactured using the nonanimal stabilized hyaluronic acid technology. This was a substudy to evaluate localization, displacement, and degradation of the gel when used for volume restoration and shaping of the buttocks.

METHODS: Subjects aged 20 years or older seeking buttock augmentation received a maximum volume of 400 ml per subject. Gel localization and degradation up to 24 months after treatment was assessed using magnetic resonance imaging. Subjects carried out a self-assessment of aesthetic improvement using the Global Esthetic Improvement Scale. Safety assessments included adverse event reporting, blood sampling for analysis of systemic inflammatory responses, and body temperature.

RESULTS: Eight subjects received a mean of 163 ml of nonanimal stabilized hyaluronic acid gel per buttock. After 6, 12, and 24 months, respectively, 56, 36, and 24 percent of gel remained in the buttocks, located primarily in the subcutaneous fat. Sixty percent of subjects rated their buttocks as improved up to 24 months after treatment. Over the 24 months, there was no gel displacement outside of the buttocks area, and the aesthetic result was not affected by minor gel displacement within the buttocks. There were no major inflammatory reactions or significant adverse events.

CONCLUSIONS: These data demonstrate that nonanimal stabilized hyaluronic acid gel degraded as expected in the buttocks, with minimal displacement. The treatment was well tolerated, and subjects' and investigators' perceptions of aesthetic augmentation of the buttocks remained high, even if only small volumes of the gel remained.

CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.