Calcification properties of saline-filled breast implants

Three patients requested explantation of their saline-filled breast implant s. Bilateral calcification had occurred in all six implants. Four of the im plants were manufactured by McGhan Corporation (Santa Barbara, Calif.), and two, by the Simaplast Company (Toulon, France). All implants had been inse rted in the subglandular plane and had been in place for 7 to 23 years. At the time of explantation, patients were 32, 34, and 44 years old. Calcifica tion on the surface of the implants and capsules was analyzed. Implant surf ace calcification was clinically evident on all six implants, appearing as ivory-colored, tenaciously adherent deposits, only on the anterior surface of the implant. Capsular calcification, which was observed only microscopic ally, was characterized by poorly organized, irregularly shaped, calcified agglomerates; this calcification also occurred only on the anterior surface of the capsule, adjacent to the area of calcification on the implant. Ultr astructural analysis of scrapings from the implant surface showed large, el ectron-dense aggregates of crystals, with individual crystals measuring app roximately 40 x 10 x 10 nm. In contrast, capsular calcification was charact erized by two patterns of deposition, spherulitic aggregates of needle-shap ed crystals and areas of metaplastic bone. The individual crystals were app roximately 40 x 10 x 10 nm. Energy-dispersive x-ray spectroscopy of specime ns from the areas of calcification on the implant and capsule surfaces demo nstrated calcium and phosphorus. Electron diffraction of crystals from the implant and capsule surfaces demonstrated the D-spacings characteristic of calcium apatite. There were many differences between the calcification prop erties of these six saline implants and those of silicone gel implants. For example, mineralization has riot been observed on the surface of gel impla nts, but in these saline implants it occurred primarily on the implant surf ace. Also, capsular calcification has been observed clinically in gel impla nts across the surface of the capsule (except at the site of attachment of a Dacron patch), but in this study it was observed only microscopically and was located on the anterior surface of the capsule, adjacent to the area o f calcification on the implant. In addition, crystals 100 times larger than those observed on the six saline implant capsules have been observed on th e surface of gel implant capsules. A model is presented to explain the mech anism of calcification associated with breast implants and to explain the o bserved differences between saline-filled and gel-filled implants.