Polyester as a bioimplantable material

In response to the recent controversy over silicone gel implants, alternative substances are being sought to offer new options in bioimplantable materials. Polyester is a Food and Drug Administration-approved prosthetic material utilized in vascular grafts for decades without significant problems in body tolerance. Working with textile scientists, polyester (both in its woven and fibrous forms) was engineered to influence differential fibrous ingrowth. Implants of medical-grade polyester were constructed in a 3-cm2 diskette configuration. Four combinations of material with varying layers of weave and fiber were created to influence tissue ingrowth differentially. Four implants were placed in separate dorsal pockets beneath the panniculus carnosus of each of 12 adult female New Zealand White rabbits. Care was taken to sort the implant types equally among the four quadrants such that a similar distribution of implants existed between animals. Implants with intact capsules were harvested at 1, 3, and 6 months, and were analyzed for histology, capsular thickness, and tissue ingrowth. A phantom mammogram was taken through the implant material that did not obscure interpretation. The materials were further tested to determine fiber fill-to-wet implant weight ratios to determine postimplantation weight predictably. Tensile strength was also determined.