Tissue expansion is a medical procedure that enables your body to "grow" extra skin for use in reconstructive procedures. This is accomplished by inserting an instrument known as a "balloon expander" under the skin near the area in need of repair. Over time, this balloon will be gradually filled with saline solution (salt water), slowly causing the skin to stretch and grow.
Once enough extra skin has been grown, it is then used to correct or reconstruct a damaged body part. This procedure is especially common for breast reconstruction.
Tissue expansion has many advantages in that the skin color and texture are a near perfect match for the area in which it is needed and there is little scarring since there is no removal of skin from one area to another. The major drawback to tissue expansion is the length of the procedure, which can be as long as four months. During this period, as the balloon expander grows, the bulge under the skin grows with it. This bulge may be desirable for a breast reconstruction patient; however, for patients undergoing this procedure for scalp repair, the bulge may be uncomfortably noticeable.