Tissue expanders are medical devices used in reconstructive surgery to grow extra skin or other tissues. They are most commonly used in breast reconstruction after a mastectomy, but also used for scar revision, repairing skin damaged by accidents, or correcting congenital anomalies. These temporary, inflatable implants gradually stretch surrounding skin, creating enough tissue for subsequent permanent implants or reconstructive procedures.
How Tissue Expanders are Placed
The surgical placement of a tissue expander involves creating a pocket beneath the skin. In breast reconstruction, this pocket is often made under the pectoralis muscle (submuscular placement), providing tissue coverage and support. Alternatively, an expander might be placed over the muscle (prepectoral placement), with an acellular dermal matrix (ADM) for support. The expander, resembling a deflated balloon, includes a self-sealing valve or port through which saline or carbon dioxide is gradually injected. This gradual filling, over several weeks or months, stretches the overlying skin and muscle, preparing the site for reconstruction.
Factors That Can Lead to Shifting
Several factors can cause a tissue expander to shift. An inadequately sized or dissected surgical pocket allows too much room for movement. Insufficient tissue coverage, particularly if the expander is placed superficially or if the overlying skin is thin, increases the risk of displacement. External trauma, such as a direct impact to the area or strenuous physical activity, can dislodge the expander, especially if it is not yet fully integrated or secured by surrounding tissue.
Early or aggressive expansion, where the expander is filled too quickly or with too much volume, can place excessive tension on the tissues, leading to instability or complications like skin necrosis. Infection around the expander or in the surgical site can compromise the integrity of the tissue pocket, making it more prone to shifting. Issues with the expander itself, such as a dislodged internal port or mechanical failure, can contribute to instability or require removal. Muscle contractions, particularly of the pectoralis muscle, can displace submuscularly placed expanders, leading to asymmetry.
Recognizing a Shifted Expander
Recognizing a shifted expander involves changes in the reconstructed area’s appearance or feel. A common sign is asymmetry, where one side appears noticeably different in shape or position. Visible bulges or an unnatural contour indicates expander movement. Discomfort or pain, particularly a new or increased sensation of pressure, tightness, or a pulling feeling, can also suggest a shift.
Skin dimpling or an uneven skin surface over the expander indicates displacement. Patients may also feel distinct expander edges or a hard, flat spot in a new location. Any noticeable change in the overall shape or projection of the expanded area warrants prompt medical attention, as early detection can influence the ease of correction.
What to Do if an Expander Shifts
If a patient suspects their tissue expander has shifted, contacting their surgeon immediately is crucial. Avoid self-manipulation or attempting independent repositioning, as this could cause further complications. The surgeon will perform a physical examination to assess the expander’s position and surrounding tissue.
Diagnostic imaging, such as an ultrasound or MRI, confirms the shift and evaluates displacement extent. Depending on the cause and severity of the shift, corrective measures can vary. These include adjusting the expansion schedule, using external compression garments for repositioning, or surgical intervention to reposition the expander or repair the tissue pocket. If the expander cannot be safely repositioned or if complications like infection are present, surgical revision or replacement may be necessary.