Keeping living tissues under tension causes new cells to form and the amount of tissue to increase. In some cases, this may be accomplished by the implantation of inflatable balloons under the skin (see figure). By far the most common method, the surgeon inserts the inflatable expander beneath the skin and periodically, over weeks or months, injects a saline solution to slowly stretch the overlaying skin. The growth of tissue is permanent, but will retact to some degree when the expander is removed.. Breast reconstruction surgery, for example, can use this technique when the mammary gland was removed by surgery (mastectomy). Later, a more permanent breast implant filled with saline or silicone gel is inserted under the expanded skin pocket.
In other applications, excess skin is grown purposely by expansion on the back or the buttocks, so that it can be harvested later for transplantation to another site where skin was lost due to trauma, extensive wounds, surgery, burns, etc.
Tissue expansion has also been used for the technique of foreskin restoration, which is usually non-surgical and applies tension externally using specialized devices to replace circumcised tissues with new cells.
Bone is another tissue that can be expanded relatively easily, by using external devices which are slowly separated using mechanical contraptions, so that bone grows in response to elongation (bone distractor). Other techniques and external devices have been studied and have shown some success, such as in the fitbone surgery. This technique was pioneered in 1951 by the Russian physician Ilizarov, and is called the Ilizarov apparatus. It is capable of lengthening limbs in cases of pathological loss of bone, asymmetry of limbs, dwarfism, short stature, etc. In reconstructive and cosmetic surgery, bone expanders have been used to elongate the mandibula in cases of congenital disorders, trauma, tumors, etc. Other newer devices such as the orthofix and intramedullary skeletal kinetic distractor (ISKD) are also used for limb lengthening. It can add over 6 inches per bone, but is expensive, painful, and time-consuming (each procedure lasts around 8-12 months).
- ↑ Neumann CG. The expansion of an area of skin by the progressive distension of a subcutaneous balloon. Plastic Reconstructive Surgery 1957;19:124-30.
- ↑ Radovan C. Tissue expansion in soft-tissue reconstruction. Plast Reconstr Surg 1984;74(4):482-92.
- ↑ External tissue expansion successfully achieved using negative pressure Zagazig University, Zagazig City, Sharkia, Egypt 2004