A positionally stable anatomic smooth breast implant.

The voluntary recall of textured breast implants due to their association with breast implant-associated anaplastic large cell lymphoma has resulted in the loss of the primary advantage of the textured surface: positional stability. We have engineered a novel soft gel-filled smooth implant with a surface that promotes positional stability without texture, known as the positionally stable smooth implant (PSSI). Miniature anatomically shaped breast implant shells were fabricated from polydimethylsiloxane using 3D-printed molds. The implant shell design incorporates cylindrical wells 1-4 mm in diameter. Implants were filled with commercial breast implant-derived silicone gel. Smooth and textured implants were also fabricated, serving as controls. Six implants per group were implanted subcutaneously into the bilateral rat dorsum. Rotation was measured every 2 weeks for a total of 12 weeks to assess stability. Animals were sacrificed at 4 and 12 weeks, and implant-capsule units were explanted for histological and Micro-computed tomography (MicroCT) analyzes. Four weeks after implantation, PSSI conditions showed tissue ingrowth and conformation to well dimensions, as assessed by histological staining and MicroCT imaging. Twelve weeks post implantation, textured implants and PSSI conditions with larger widths, depths, and well number demonstrated statistically significant increased stability compared to smooth implants (< 0.05). Tissue ingrowth into shell features occurred by 4 weeks and remained throughout longer time points. No significant differences were found in capsule thickness or collagen content between groups. These results suggest a promising alternative to textured surfaces for inducing implant positional stability.