Ultimate Strength Properties of Control and Explanted Silastic O and Silastic I Silicone Gel-filled Breast Implant Shells

Background

The effect of in vivo implantation on breast implants is important to both physicians and patients, but little information about the in vivo aging process of silicone gel-filled breast implants has appeared in the literature. The effects of the in vivo aging process could affect the durability of breast implants.

Objective

The purpose of this study was to investigate changes in the mechanical and chemical properties of breast implant shells as a function of implantation time.

Methods

The ultimate mechanical properties of the shells from single-lumen silicone gel-filled Silastic O and Silastic I explants with in vivo duration times ranging from 6 to 28 years were measured and compared with the corresponding properties of unimplanted control single-lumen silicone gel-filled implants. Ultimate tensile strength, elongation-to-failure, and tear resistance were measured for both explant and control shells through use of identical testing protocols. In addition, the tensile strength and elongation-to-failure of shells extracted with hexane to remove non–cross-linked silicones were measured for both explants and control implants. The ultimate strength data were plotted as a function of implantation time, along with data from other research institutions.

Results

Statistical analysis of the data indicated that the ultimate mechanical properties of tensile strength, elongation-to-failure, and tear resistance are not functions of implantation time for up to 28 years of implantation.

Conclusions

The results of this study show that there is no significant degradation of the mechanical properties of the elastomeric shell as a function of time.