Tissue expansion is widely used in reconstructive surgery. The rationale of this procedure is to reconstruct a each anatomical region with the surrounding healthy tissues that are expanded to achieve a greater surface.
The technique is based on the physiologic principle that skin and soft tissues under constant traction increase their surface through a process of cell replication and a rearrangement of elastic fibers.
The indications are several and could be grouped as follows:
- Breast reconstruction
- Removal of large skin neoplasms (e.g. giant nevi)
- Removal of large areas of scarring (e.g. large scars secondary to burns or trauma)
Expanders are silicone implants that are placed under the skin (general-purpose tissue expanders) or under the pectoralis major muscle (breast reconstruction).
The expander is composed by a main chamber, where the saline solution is contained, and a valve. This could be external, linked to the main chamber with a silicone tube, or integrated on expander surface. The expander are then inflated with saline solution on weekly basis with a percutaneous injection on the valve that allow the inflow of saline while avoiding its leakage.
Expanders are available in several shapes and sizes. Breast expander usually have an integrated valve, while general-purpose tissue expanders have an external valve.
Expansion generally begins one or two weeks after the implant procedure and are performed on a weekly basis. The total duration is 2-3 months, depending on the size of the expander and of the anatomical region (e.g. the lower limb requires a slower expansion). In case of large lesions, two or more expanders could be implanted to maximize the results.
When a satisfactory cutaneous expansion is achieved, the expander is removed with a second surgical procedure. In case of breast reconstruction, the expander is then replaced with a definitive silicone implant. In case of skin lesions (e.g. giant nevi, scars) the target area is removed and the pre-expanded skin is employed for reconstruction.
Apart from breast expanders that are usually placed under the pectoralis major muscle, the postoperative of these procedures (expander placement and removal) is not painful. To avoid bruising and subcutaneous fluid collection, drainages are placed during surgery. Drainages consist of small tubes of soft silicone, usually removed 2-4 days after surgery.
Resorbable sutures are preferably applied. In other cases, non-resorbable sutures are removed 2-3 weeks after surgery.