For many patients considering breast augmentation, the concept of cleavage is central to their goals. A sculpted, natural-looking space between the breasts often enhances confidence, flatters clothing, and contributes to an elegant overall silhouette. However, when procedures are performed without careful planning or respect for individual anatomy, the pursuit of dramatic cleavage can sometimes result in a complication called symmastia.
Symmastia, often referred to as “uniboob,” occurs when breast implants or breast tissue migrate across the midline of the chest, erasing the natural separation that defines cleavage. While rare, it is a concern that underscores the importance of thoughtful surgical technique, appropriate implant selection, and long-term planning. At Studio Plastic Surgery in Toronto, we believe that understanding this distinction helps patients make safer choices and achieve their desired look without unnecessary risks.
What Is Cleavage?
Cleavage refers to the natural or enhanced space between the breasts. In breast augmentation, it is often created or accentuated by the placement of implants, the patient’s underlying anatomy, and how tissue settles over time. When done correctly, cleavage looks soft, proportionate, and harmonious with the rest of the chest and body.
The goal of surgery is not to force the breasts unnaturally close together, but rather to enhance the patient’s natural curves. The result should look attractive both with and without clothing, while still maintaining comfort and stability.
What Is Symmastia?
Symmastia is a condition where breast implants or tissue migrate across the midline of the chest, creating the appearance of one continuous breast mound. Instead of a flattering space between the breasts, the skin may appear lifted or stretched, and patients may feel discomfort or pressure along the sternum.
There are two forms of symmastia:
- Congenital Symmastia
This rare condition is present from birth and occurs when soft tissue develops across the sternum, blending the breasts together. It is not caused by surgery and typically requires corrective procedures later in life to restore natural separation and create a more defined cleavage line. - Iatrogenic Symmastia
The more common form, iatrogenic symmastia, develops as a complication after breast augmentation. It happens when implants are placed too close together or the surgical pocket is over-dissected, allowing implants to drift inward. Revision surgery is usually needed to re-establish proper separation and support.
Iatrogenic symmastia is the more common concern, and fortunately, it can be prevented with careful planning and corrected if it occurs.
Why Does Symmastia Happen?
Several factors can contribute to the development of symmastia:
- Overly Large Implants – Choosing implants that are too wide for the chest can cause them to extend into the cleavage area.
- Over-Dissection of the Pocket – If too much tissue is released near the sternum, implants can drift inward over time.
- Weak or Thin Tissue – Some patients naturally have less supportive tissue, making it easier for implants to migrate.
- Improper Implant Placement – Positioning implants without respecting chest wall anatomy increases the risk of crossing the midline.
These issues highlight why implant selection and surgical expertise are crucial.
Preventing Symmastia: Safe, Beautiful Cleavage
At Studio Plastic Surgery, prevention is always the first priority. During your consultation, our surgeons perform a detailed anatomical assessment to determine the best implant size, shape, and placement for your body. By respecting your chest dimensions and tissue characteristics, we create results that look both beautiful and stable.
Preventative measures may include:
- Selecting implants that match your natural breast base width.
- Avoiding over-dissection of tissue near the sternum.
- Reinforcing implant pockets when needed to add long-term support.
- Using supportive garments during the early healing phase to help implants settle properly.
By prioritizing these steps, we ensure that cleavage looks natural and proportionate—without risking implant migration or discomfort.
Correcting Symmastia
If symmastia does occur, it can be corrected through revision surgery. Depending on the severity, this may involve:
- Repairing the Implant Pocket – Reinforcing the tissue between the breasts to recreate separation.
- Adjusting Implant Placement – Moving implants to a plane or position that better suits the patient’s anatomy.
- Changing Implant Size or Type – Replacing implants with more appropriate dimensions.
- Tissue Reinforcement – Using sutures or biologic mesh to support the midline area.
Although revision surgery requires careful planning, many patients achieve excellent long-term outcomes and restored confidence after correction.
The Takeaway
Cleavage is one of the most sought-after outcomes of breast augmentation, but it should always be approached with balance and safety in mind. Symmastia, while rare, is a reminder that respecting natural anatomy is essential for lasting, beautiful results.
At Studio Plastic Surgery in Toronto, we believe that patients deserve results that look elegant, natural, and sustainable. By combining careful planning, advanced techniques, and personalized care, we help you achieve your vision for enhancement—without unnecessary risks.
If you are considering breast augmentation or have concerns about your results, we invite you to book a private consultation. Our team will guide you through every step of the process, ensuring your goals are met with artistry, expertise, and compassion.
Sources Cited
- HealthCentral – What Is Symmastia? Causes and Diagnosis
- Biology Insights – What Is Symmastia? Causes and Correction Options
- Oxford University Press, Aesthetic Surgery Journal – Techniques in Symmastia Correction
