Expander/implant reconstruction is the use of an expander to create the shape and desired size of a breast. This is later exchanged with the placement of a breast implant.
Expanders are temporary inflatable implants that are placed under the pectoralis muscle and enable the skin and soft tissues of the breast to grow. Over a period of several weeks, the expander is gradually filled with saline solution through a port that lies just under the skin. Once the expander has been completely filled, it is left in for several more weeks to months, preparing the body for the placement of the breast implant.
In a separate surgery, your expander is exchanged for a permanent breast implant. Implants are filled with silicone or saline and are used to form the shape and desired size of the breast.