**7. Implant based reconstruction (IBR)**

IBR entails using a breast implant (silicone or saline) to create a breast mound after mastectomy. The advantages of IBR are that this procedure is relatively simple, expedient, and has short recovery time. The disadvantages are implant related

complications such as implant rupture, exposure, extrusion, and capsular contractures [29]. IBR can be performed in a single or two stage technique. In a single stage IBR, the plastic surgeon places the breast implant to reconstruct the breast mound at the same operation immediately after mastectomy [30]. Alternatively, IBR can be performed in two stages. This is particularly useful in cases where extra skin needs to be recruited. In this approach, a tissue expander is placed first at the time of mastectomy. The device is expanded over time on a weekly basis in the medical office. Several months later, the second stage of the procedure is performed where the tissue expander is removed and replaced with a permanent breast implant [31].

Irrespective of single or two stage implant reconstruction technique, anatomically, these devices (expander and/or implant) can be placed either above or below the pectoralis muscle. In the early period of breast reconstruction, pre-pectoral (above the pectoralis muscle) implant placement was abandoned due to high rates of capsular contracture, implant extrusion and poor esthetic results. Subsequently, the shift to subpectoral plane (under the pectoralis muscle) offered an increased coverage of the implant and less of the above implant related complications However, over the years it became apparent that submuscular implant placement is associated with chronic muscle related pain, muscle spasms, animation deformity, and reduced physical mobility. With optimization of mastectomy technique, advances in radiotherapy, use of alloplastic devices, fat grafting, and new implant designs, the prepectoral approach has undergone a revival and is now performed in many centers around the world [32].

With certain surgical advancements, oncologic surgeons are transitioning to SSM and NSM. Technological breakthrough has contributed to the availability of mesh (Human/animal/synthetic) for reconstructive support [33]. Improvements in the breast implant device characteristics have led to improved outcomes for patients undergoing IBR as well. Furthermore, due to these advances in mastectomy techniques, and the recent increase in bilateral mastectomies performed, IBR is the most common approach currently used for breast reconstruction. According to The American Society of Plastic Surgeons 2018 publication, 40% of women who underwent mastectomy had reconstruction and the most common practice in the US was immediate reconstruction (75% of the cases) of these 81% corresponded to Implant based (two-stage 68%, one stage 13% (**Figures 5** and **6**) [34].

#### **Figure 5.**

*36 year old female with history of bilateral SSM and immediate subpectoral implant based BR. Of note she also had bilateral nipple reconstruction.*

#### **Figure 6.**

*28 year old female with history of BRCA gene mutation. Left: demonstrates her pre surgery (pre mastectomy). Right: patient 6 months after Bilateral prophylactic NSM with immediate prepectoral implant based BR.*
