Breast Tissue Expanders

April 10, 2025

This page was reviewed under our medical and editorial policy by Susan Yost, Ph.D., staff scientist, Department of Medical Oncology & Therapeutics Research, City of Hope^® Cancer Center Duarte

When a patient chooses breast reconstruction surgery, tissue expanders may be the first step in the process, and performed during or after breast cancer surgery, such as mastectomy or lumpectomy.

After the removal of skin and breast tissue during surgery for breast cancer, there may not be enough tissue left to cover a breast implant or new tissue flap. Tissue expanders are placed in the breast for several months to stretch and expand the remaining tissue. This paves the way for breast reconstruction options for the patients who want to restore the shape of their breast(s).

What Is a Tissue Expander?

A tissue expander, which is typically made of silicone, is like an empty balloon with a one-way valve attached. Once placed in the breast, the valve may be under the skin or poking out from the skin. The tissue expander is a placeholder — and it helps to keep the form of the breast intact so that the surgeon may reconstruct the shape of the breast later with implants and/or tissue flaps.

For many patients undergoing breast reconstruction, tissue expanders are placed right after mastectomy or lumpectomy during the same operation (sometimes called immediate-delayed reconstruction).

After healing from surgery, the patient periodically visits the doctor, who injects small amounts of saline (saltwater) or carbon dioxide into the expander through a valve. This causes the expander to enlarge and stretch out the tissue and skin over several months in preparation for breast reconstruction surgery.

According to the National Cancer Institute, the second implant or flap reconstruction surgery is typically performed two to six months after a mastectomy with a tissue expander, but the procedure may be safely delayed and scheduled at any time by the patient and the care team.

It is important to note that expanders and breast implants are not the same.

Expanders remain in place for a short period of time (typically several months), while implants are meant to remain in place longer (typically 10 to 15 years).

Expanders are slowly inflated over time with saline or carbon dioxide to stretch the skin and change the shape of the breast, while implants remain the same size after they are inserted and are typically filled with saline or silicone.

Some patients choose to delay breast reconstruction and have the expander placed at a later time. Patients may wait for tissue expander placement and breast reconstruction for several reasons, including:

• They want to finish breast cancer treatments before thinking about reconstruction
• Other health conditions need treatment before reconstruction
• They need to quit smoking (smoking may delay healing after surgery)
• They are undergoing radiation therapy treatment for breast cancer

Some patients, such as those who are young and have small breasts, may be candidates for full reconstructive surgery at the same time as their mastectomy, which is known as direct to implant reconstruction. Expanders are not used in this case.

What to Consider

Today, expanders come in many shapes (oval, round or teardrop) and sizes, which gives patients a wide choice of options. They also differ in the type of casing surface (smooth or textured), how the valve works and what the expander is filled with. The sizes relate to volume and are most often referred to in cubic centimeters, or cc. The expanders range from 50 cc to 1,000 cc and usually go up in increments of 50 cc to 100 cc.

Decisions about placement, type and sizing are made carefully by each patient and the care team. The patient’s goals, available tissue after mastectomy, skin quality, breast size and the expertise of the surgeon are all taken into account.

Tissue expanders and breast implants may be placed either under the chest muscle (subpectoral placement) or on top of the chest muscle (prepectoral placement), as detailed below.

Subpectoral placement: This is the most common method. However, with a total submuscular approach under the chest muscle, it may distort the appearance of the breast when the muscle covering the chest wall contracts. Newer methods that separate the expander from part of the chest muscle (partial submuscular or dual-plane) using material called acellular dermal matrix (ADM) to keep it in place allow for a more natural appearance. ADM is made from human or animal skin and naturally absorbed.

Prepectoral placement: This does not involve cutting into the chest muscle. The expander sits on top of the muscle with ADM or stitches that keep it in position. It is often a shorter procedure with less pain afterward.

The expander may be filled more during the procedure compared to the subpectoral methods.

What to Expect

Before tissue expander placement (either as part of mastectomy or as a separate surgery), patients meet with the surgeon to discuss how to prepare for surgery, what will happen during the procedure and what to expect afterward, as detailed below.

Antibiotics: These may be given just before surgery to reduce the risk of infection.

Anesthesia: The procedure is performed under general anesthesia, which means patients will be asleep and not feel any pain.

Pain, anti-nausea medication: Drugs to reduce pain and stress on the body and prevent nausea may also be given during surgery through an intravenous (IV) line that is inserted into the arm or top of the hand.

Nerve blocks: The care team may also administer a nerve block to help prevent pain immediately after surgery.

How long it takes: The surgery to place breast tissue expanders takes about one to two hours. The expanders are flat when they are inserted, but some may be inflated slightly during surgery.

Recovery: After surgery, patients will either remain in the hospital or return home the same day.

Healing: After about two to four weeks of healing, the tissue expander can start to be inflated. Patients will visit their health care provider who uses the valve in the expander to inject a small amount of saline or carbon dioxide. This causes the expander to inflate slightly, stretching the skin and surrounding tissue. Typically, this will be done every one to three weeks. Tissue expanders are left in place anywhere from four to 18 months, depending on the breast size wanted and whether other treatments are needed.

Sleeping With Tissue Expanders

After initial placement and for an hour or two after each filling, a patient may experience some pain. Doctors may prescribe medication to treat the pain, and it may be uncomfortable to sleep after a filling appointment. Also, it is important to avoid any pulling or stretching in the chest area from side or stomach sleeping.

Patients should sleep on their back for several weeks and may find that sleeping in a more upright position, such as in a recliner, may be more restful. If a recliner is not available, pillows may be used to sleep with the chest up at an angle. Some patients practice this for weeks before surgery.

Tissue Expander Complications

After surgery, patients should report any problems to their doctor, such as excessive pain, swelling or discoloration of the skin near the expander. Complications that may occur after breast tissue expanders are placed include:

• Hematomas (bleeding under the skin near the site of the expander)
• Infection
• Lack of blood supply to the skin that is being stretched, causing tissue death
• Capsular contractures (a type of hardening or scarring around the expander)
• Device complications, such as deflation from a needle puncture or the expander poking through the skin (extrusion)