Summary
Expander implant reconstruction begins with a tissue expander, placed at the time of mastectomy. A tissue expander is a temporary implant with a built-in fill port that allows surgeons to slowly expand soft tissue. That expansion creates a pocket that is large enough to hold a permanent breast implant. This approach works well for women whose skin quality does not permit direct-to-implant reconstruction.
When a tissue expander is placed during surgery, it is partially filled with saline to provide the beginning of a breast shape. The expander is then further filled with saline during office visits in the weeks after surgery. This is done with a saline filled syringe and needle placed through the skin into a fill port in the expander. Once it reaches the desired volume, the expander is replaced with a final implant in a second stage procedure.
Types of Expander Implant Procedures
Prepectoral Breast Reconstruction

Expander OTM following nipple-sparing mastectomies is completely covered with a dermal matrix (beige). Saline is injected into the expander through the expander port in the office to achieve final volume.
Subpectoral Breast Reconstruction

Expander partially UTM following nipple-sparing mastectomies with pectoralis muscle above (red) and dermal matrix below (beige). Saline is injected into the expander through the expander port in the office to achieve final volume.
Full Submuscular Breast Reconstruction
In some cases, a plastic surgeon may prefer to place the expander completely under-the-muscle (UTM), with the pectoralis muscle covering the upper half and the serratus muscle covering the lower half of the expander. This may be surgeon preference or may be required in cases where the mastectomy skin is compromised.
Procedure details:
- At the time of the mastectomy, a tissue expander is placed either over or under the pectoralis muscle
- A dermal matrix may be used to help support the soft tissue and the expander
- Saline is injected into the expander implant through a built in port during office visits after surgery
- Patients can decide when they are happy with the volume of the expander
- Once expansion is complete, the final implant is placed during an outpatient procedure
Risks & Benefits
Placing a tissue expander requires good quality skin at the mastectomy site. Most people who undergo mastectomy are candidates for staged tissue expander-implant breast reconstruction. This approach is ideal for women who do not want to have a natural-tissue flap procedure or for those who do not have good flap options for breast reconstruction.


