What is symmastia after breast augmentation?

This condition is often caused by factors such as choosing implants that are too large for the patient's anatomy, overly aggressive dissection of the implant pocket, especially across the midline, and inadequate formation of the lateral pocket, which can lead to persistent pressure on the cleavage area.

Motiva implant explantation. Photo courtesy of Dr. Ho Cao Vu

In breast augmentation surgery, the surgeon must carefully assess the position and width of the sternum to determine how the implant pocket should be dissected. The implant should be positioned such that its medial edge lies close to the sternum, but not too close and not too far. The cleavage area comprises only skin, fat, and connective tissue, while the fascial and muscular structures in this region are relatively thin compared to other parts of the breast, and in some individuals, a narrow, elongated, or mildly concave sternum may also affect the overall shape of the breast. Therefore, the surgeon must plan the implant pocket dissection carefully and select an implant appropriate for each patient's anatomical structure of the breast to avoid complications such as symmastia.

According to MD, MSc. Ho Cao Vu, who has over 15 years of experience in revision breast surgery, implant size selection must be based on key parameters, including diameter, projection, and anatomical structure.

"Everybody has their anatomical limits—if the implant is too large relative to the anatomical structure of the breast and the implant pocket is undersized, over time the implant may be pushed medially toward the cleavage area," Dr. Vu said.

Allergan implant explantation. Photo courtesy of Dr. Ho Cao Vu

Many women seek closely spaced cleavage for aesthetic reasons. However, if the surgeon dissects the pocket too far medially to place the implants closer together, uses implants that are too large, or if the patient applies excessive inward pressure by tightening their compression bra, these actions can all contribute to the development of symmastia.

Below, Dr. Vu outlines the most common causes of symmastia, which can arise from both surgical technique and improper postoperative care:

Implants too large for the patient's anatomy

Every individual has a unique chest structure - including the natural gap between the breasts, the distance from the clavicle to the nipple, the vertical distance from nipple to inframammary fold, and variations in chest wall contour.

Selecting implants that are disproportionately large for the patient's body can lead to complications like symmastia. Choosing implants that match the patient's anatomical proportions is essential to achieving balanced, long-term aesthetic outcomes and avoiding complications.

Implant pocket dissection. Photo courtesy of Dr. Ho Cao Vu

Over-dissection of the implant pocket toward the sternum

The area between the breasts is where the skin attaches to the sternum. If the implant pocket is dissected too aggressively along the medial fascia, without properly releasing the lateral border, the soft tissue may become overstretched. This can cause the implants to shift medially, resulting in merged breasts and outward-pointing nipples.

In some cases, this complication results from both an oversized implant and an overly large implant pocket.

Ignoring anatomical limitations

In certain patients, it may not be anatomically feasible to create narrow cleavage. If the surgeon prioritizes cosmetic goals over anatomical reality, delayed complications like symmastia can occur. This is particularly true in patients with naturally wide-set chests.

Implant pocket dissection. Photo courtesy of Dr. Ho Cao Vu

Incorrect use of compression bras during recovery

Wearing a compression bra too tightly to force the breasts inward may apply continuous pressure on the sternum and lead to symmastia. Patients should follow their surgeon's post-op garment instructions carefully and avoid adjusting the bra's fit or applying pressure in an attempt to enhance cleavage.

Case study: Vietnamese patient with prior surgeries

A Vietnamese patient living abroad had undergone three previous breast surgeries: the first was a breast augmentation performed 10 years ago, followed by implant removal in the second, and a third surgery using a lateral incision to place new implants.

The patient later developed symmastia and a significantly oversized implant pocket, which led to lateral implant displacement and hypertrophic scarring along the old incision site.

She was referred for consultation and underwent revision surgery, which involved implant removal, symmastia correction, and new implant placement. The surgeon made an incision along the infranipple fold, removed the previous 355cc textured implant, reconstructed the pocket to match the new implant, and performed scar revision with aesthetic closure.

For symmastia cases, Dr. Vu emphasized that corrective procedures must be performed at a fully equipped general hospital as they are major surgeries requiring maximum safety. "In many cases, we must recreate the implant pocket and replace the implant," he said.

Patients are advised to carefully consider the surgical plan and select implant types and sizes suited to their individual anatomy to minimize the risk of complications like symmastia.