Preliminary report of de novo adipogenesis using novel bioabsorbable implants and image evaluation using a porcine model

Our bioabsorbable poly-l-lactic acid (PLLA) mesh implants containing collagen sponge are replaced with adipose tissue after implantation, and this is an innovative method for breast reconstruction. In this preliminary study, we investigated the formation of adipose tissue and evaluated the process via multimodal images in a porcine model using an implant aggregate to generate the larger adipose tissue. The implant aggregate consists of PLLA mesh implants containing collagen sponge and a poly-glycolic acid woven bag covering them. We inserted the implant aggregates under the porcine mammary glands. Magnetic resonance imaging (MRI), ultrasonography (USG), and 3-dimensional (3D) surface imaging and histological evaluations were performed to evaluate the formation of adipose tissue over time. The volume of the implant aggregate and the formed adipose tissue inside the implant aggregate could be evaluated over time via MRI. The space within the implant aggregate was not confirmed on USG due to the acoustic shadow of the PLLA threads. The change in volume was not confirmed precisely using 3D surface imaging. Histologically, the newly formed adipose tissue was confirmed on the skin side of the implant aggregate. This implant aggregate has the ability to regenerate adipose tissue, and MRI is an appropriate method for the evaluation of the volume of the implant aggregation and the formation of adipose tissue.