Breast Reconstruction Following Mastectomy

The goal of this clinical trial is to learn if adding an allogeneic (donor) nerve graft during breast reconstruction can improve recovery of breast and nipple sensation in women undergoing bilateral nipple-sparing mastectomy with implant-based breast reconstruction. The main questions it aims to answer are: * Does nerve grafting improve objective breast sensation compared with reconstruction without nerve grafting? * Does nerve grafting improve patient-reported breast sensation? Researchers will compare the breast that receives the nerve graft with the breast that does not receive a nerve graft to determine whether nerve grafting improves sensory recovery. Participants will: * Undergo bilateral nipple-sparing mastectomy with immediate implant-based breast reconstruction as planned standard care. * Receive an allogeneic nerve graft (Avance Nerve Scaffold) on one breast, with the side receiving the graft determined randomly. * Have breast sensation measured using a light-touch test before surgery and at approximately 6, 12, and 24 months after surgery. * Complete questionnaires about breast sensation at the same time points.

Patients can undergo breast implant surgery for multiple reasons; cosmetic and reconstructive being the primary indications. In order to confidently state safety and due to strict regulation on medical devices it is important to maintain a record of safety and performance with all medical implants. This study is designed to collect data on a new generation of smooth mammary implants to assess the long term performance and safety data on this type of gel-filled mammary breast implant. The two main complications of breast implants are capsular contracture and rupture; these complications can take years to develop. The study is designed to evaluate the occurrence of these two primary complication as well as other secondary complications over a period of 10 years. Patient follow up will be carried out pre-operatively and post operatively at 12 months and then 3, 5, 8 and 10 years thereafter. The study will be carried out over 10 years to adequately assess complications which may only occur over the lifetime of the device such as systemic complications