Polydioxanone thread insertion in combination with radio frequency treatment does not exhibit synergistic efficacy: Animal study with pigs.

Abstract

Polydioxanone (PDO) thread insertion and monopolar radio frequency (RF) treatment are two common antiaging modalities. The efficacy and safety profile of PDO in combination with RF treatment is unknown. To investigate pathological changes in skin in response to PDO+RF treatment in an animal model. PDO threads were implanted into the skin of young white domestic pigs. RF treatment was performed on the PDO insertion sites 2weeks after the PDO procedure. Skin biopsies were taken at 6 and 12weeks after PDO for histological examination. Both PDO and PDO+RF treatments induced the fibrous granular formation surrounding the PDO threads. There were more exaggerated inflammatory responses such as development of nodular panniculitis and adipocyte necrosis in the skin at 6weeks after PDO+RF as compared with PDO alone, which was largely resolved at 12weeks. All treatments led to thickened and replicated interlobular septa, many of which were connected to the collagenous network in dermis. In all treatment groups, the cross-sectional areas of the dermal collagenous bundles were significantly increased at both endpoint times as compared with the baseline level. PDO+RF treatment did not lead to increases in neocollagenesis as compared with PDO or RF treatment alone. Our data showed that RF and PDO induced comparable levels of collagen remodeling in the skin. PDO+RF treatment did not exhibit evident synergistic effects of derma collagen remodeling but rather amplified the inflammatory responses in the skin. Therefore, combined treatment is not recommended.