Impact of Hematoma on Capsular Contracture: A Comparative Study of Smooth and Textured Implants in a Miniature Pig Model.

[BACKGROUND] Capsular contracture is a significant complication following mammaplasty, with varying incidence rates and symptoms. The etiology of capsular contracture is multifactorial, with postoperative hematoma recognized as a potential contributing factor.

[OBJECTIVES] In this study we aimed to investigate the impact of postoperative hematoma on capsular contracture following mammaplasty, utilizing pig models and modified biomechanical testing. We sought to compare the severity of capsular contracture between smooth and textured implants in the presence of hematoma, assess the biomechanical properties of the capsules, and explore the histological and molecular changes associated with the condition.

[METHODS] The study involved 5 female miniature pigs, implanted with both smooth and textured implants. Hematoma models were established, and various methods were employed to evaluate the impact of the prosthesis surface and hematoma on capsular contracture, including ultrasound assessment, biomechanical tests, scanning electron microscopy, histological analysis, and transcriptome sequencing.

[RESULTS] Capsules in hematoma groups were classified as Baker III/IV, with significantly unfavorable thickness, elastic modulus, and relaxation and creep amounts compared to nonhematoma groups. Smooth implants under hematoma conditions exhibited increased muscle content and biomechanical strength of the capsule. Transcriptomic analysis highlighted differential gene expression related to muscle development and contraction in smooth implants with hematomas.

[CONCLUSIONS] Hematomas increase the risk of capsular contracture, with smooth implants exacerbating this effect by enhancing pathways related to muscle development and contraction. This underscores the importance of hematoma prevention and treatment strategies, particularly when placing smooth implants, to minimize the occurrence of capsular contracture. The study provides insights into the mechanisms underlying capsular contracture and offers evidence to guide surgical and postoperative management strategies.