Mentor is undertaking a five-year prospective clinical study designed to collect safety data associated with the implantation of its gel-filled mammary prostheses. This study is an "adjunct" study, which will encompass clinical reviews of reconstructive cases in all patients who meet clinical and regulatory criteria for breast reconstruction with gel-filled mammary prostheses. This "adjunct" study will be accomplished under a limited clinical protocol in which specific parameters will be required but with controls somewhat less stringent than those normally required in Investigational Device Exemption (IDE) Trials.