Defining the Relationship between Pocket and Breast Implant Surface Area as the Basis for a New Classification System for Capsular Contracture

Background: The precise etiology and treatment for capsular contracture remains uncertain at least partially due to the fact that there is no reliable quantitative measurement tool. To address this, it is postulated that the surface area of an implant as defined by the surrounding pocket may provide a quantifiable variable that can be measured to evaluate the degree of capsular contracture. Methods: A bench model for capsular contracture was developed. The surface area of a series of spherical test objects and non-contracted and contracted breast implants was measured using a wax coating technique as well as three-dimensional reconstructions created from CT scan images. Results: Comparison of the mathematically calculated surface areas to the wax and CT results for spheres of known dimension provided nearly identical values documenting the accuracy of the two experimental methods. Comparison of the surface area measurements between the test groups showed that the average decrease in surface area for all implants was 20%, ranging from a high of 30.9% for a low profile implant to a low of 14.1 % for a high profile implant. The anatomically shaped devices demonstrated nearly uniform degrees of surface area change over three different heights with volume and projection held relatively constant. Conclusions: The described bench model provides a useful tool for the study of capsular contracture. Surface area is a descriptive variable that can assess the degree of capsular contracture that is present. A classification system based on surface area is presented.