Ivalon breast prostheses: evaluation 19 years after implantation.

Ivalon sponge prostheses, which had been removed from a patient after 19 years, were studied mechanically by light microscopy, by scanning electron microscopy, and by dot map x-ray microanalysis. This study revealed the following. The firmness of these implants was due entirely to their external fibrous capsule, which was 4 to 5 mm in thickness. Once this capsule was incised through, the mechanical compression properties of the implants were identical to fresh unused Ivalon sponge. Contrary to previous observations that Ivalon sponge becomes extensively infiltrated with fibrous tissue, the present implants demonstrated fibrous tissue ingrowth only 2 to 3 mm into the sponge. The open porous nature of the sponge had been preserved after the 19-year implantation period. Whereas extensive calcium and phosphate deposition had previously been demonstrated when Ivalon was implanted into animals, no significant deposition of these ions was observed in the present study.