Dr Scott J Turner | Specialist Plastic Surgeon (FRACS)
Key Takeaways
- Symmastia is a joining of the breasts across the midline. The skin over the breastbone lifts away, and the normal gap between the breasts is lost.
- Most cases follow breast augmentation, when the implant pockets extend too far toward the midline. A rarer congenital form occurs without implants.
- The telltale sign is skin that tents across the breastbone rather than dipping down to it. A close cleavage with the skin still attached to the bone is not symmastia.
- Established symmastia does not resolve with garments or time. Correction is surgical and rebuilds the inner wall of each implant pocket.
- Symmastia correction is a demanding form of implant revision, recurrence is possible, and outcomes vary between individuals.
Symmastia is an uncommon complication of breast augmentation. It is often first noticed as a change in the cleavage: the breasts sit closer together than they did, or the skin in the middle of the chest no longer dips down to the breastbone. Because a close cleavage can look similar, part of any assessment is telling the two apart.
This guide covers what symmastia is, why it happens, how it differs from close cleavage, the rarer congenital form, and how correction surgery is planned. Procedure detail sits on the breast implant revision and removal page, and the wider set of complications after augmentation is covered in breast augmentation risks and complications.
What symmastia is
Symmastia, sometimes spelt synmastia, describes breasts that meet or merge across the midline of the chest. Normally the skin in the centre of the chest is firmly attached to the breastbone (sternum), and that attachment creates the gap between the breasts. In symmastia the attachment is lost, or never formed, so the skin bridges from one breast to the other.
It is sometimes described informally as a “uniboob” or as “bread-loafing”. Those words are also used for the shape a compressive sports bra creates, which is a different thing entirely.
There are two forms:
- Implant-related symmastia, which develops after breast augmentation or other breast surgery. This is the form most often seen in practice.
- Congenital symmastia, which is present without any surgery and is caused by a web of tissue across the breastbone.
Why symmastia happens after breast augmentation
Each implant sits in a pocket created at surgery. The inner edge of that pocket is bounded by the tissue attached to the breastbone. If the pocket is created too far toward the midline, or its inner wall stretches over time, the two pockets can meet and the skin over the breastbone separates from the bone.
Factors that increase the risk include:
- implants that are too wide for the chest, so the pocket has to extend toward the midline to accommodate them
- over-release of the inner attachments of the chest muscle or of the tissue over the breastbone
- thin soft tissue over the breastbone, which gives the pocket wall less support
- pressure from larger implants over time, which can gradually stretch the inner wall of the pocket
- previous surgery in the same area
Symmastia can appear soon after surgery, or develop gradually over months or years as the pocket stretches.
Signs of symmastia
The most reliable sign is what happens to the skin in the middle of the chest.
- The skin across the breastbone tents or lifts, rather than dipping down to meet it.
- The gap between the breasts narrows or disappears. In more pronounced cases the breasts appear as one continuous shape.
- The implants can sometimes be felt, or seen, close to or across the midline.
- Pressing on one breast may move the other.
Symmastia ranges from mild, where a shallow bridge of tissue remains and some cleavage is kept, to complete, where there is no separation between the breasts at all.
Close cleavage or symmastia?
Many patients want a narrow cleavage, and a close cleavage is not a complication. The distinction lies in the skin over the breastbone. With close cleavage, the skin stays attached to the bone and there is still a defined gap, however narrow. With symmastia, the skin has separated and bridges between the breasts. A surgeon can usually tell the two apart on examination, and the difference determines whether any treatment is needed.
Congenital symmastia
Congenital symmastia occurs without implants or previous surgery. A web of skin and soft tissue crosses the breastbone and joins the breasts, and it usually becomes noticeable as the breasts develop. Its cause is not well understood.
Correction is surgical. It typically involves reducing the tissue across the breastbone and supporting the skin so it can re-attach to the bone as it heals. Because the problem lies in the tissue over the breastbone rather than in an implant pocket, the approach differs from implant-related symmastia.
Surgical correction of symmastia
Established symmastia does not resolve on its own, and garments or taping alone do not re-attach the skin to the breastbone. Correction is surgical, and the plan depends on the cause, the implants in place and the tissue available.
Techniques include:
- Capsulorrhaphy. The inner part of the capsule, the scar tissue around the implant, is folded and sutured to rebuild the inner wall of the pocket.
- A new pocket. Where the existing pocket cannot hold a repair, a fresh pocket is created, sometimes in a different tissue plane. This can mean moving the implant from above the chest muscle to below it, or the reverse.
- Internal support. Sutures or a resorbable surgical mesh can reinforce the repaired pocket wall while the tissues heal.
- Implant exchange. Narrower or smaller implants reduce the pressure on the repair and suit the width of the chest.
- Implant removal. Some patients choose removal instead of another revision. The implant removal decision guide sets out how that choice is weighed.
After surgery, a support garment designed to hold the breasts apart, often called a symmastia bra, is worn for the period Dr Turner advises. It protects the repair while the skin re-attaches. More detail on the techniques is on the breast implant removal and revision page.
Recovery
Recovery follows the pattern of other implant revision surgery. Surgery usually takes 1 to 3 hours, and an overnight stay in hospital with drains is generally recommended. Most patients return to desk-based work within about two weeks. Upper body exercise and anything that presses the breasts together are avoided for longer, typically around six weeks, and the support garment is worn as advised throughout. The breasts continue to settle over the following months.
Risks and the chance of recurrence
Symmastia correction is one of the more demanding forms of implant revision, because the repair relies on tissue that has already stretched. Risks include:
- recurrence of symmastia
- asymmetry
- capsular contracture
- visible or palpable implant edges, or rippling
- fluid collection
- infection
- scarring
- changes in nipple sensation
- the need for further surgery
- the general risks of anaesthesia
Recurrence is more likely when the tissue over the breastbone is thin, or when larger implants are kept. Outcomes vary between individuals, and what is realistic for your anatomy is discussed at consultation.
Medicare and cost
Medicare items 45553 and 45554 cover replacing implants only after rupture, migration of prosthetic material or symptomatic capsular contracture. Unless the original implants were placed in the context of breast cancer or a developmental abnormality, the items also require intra-operative photographs showing that removal alone would leave an unacceptable deformity, and no benefit is payable where surgery is performed solely to increase breast size. Symmastia is not named in either item, so correction after cosmetic augmentation is generally not Medicare-rebated. Because each correction is planned around the individual findings, fees are quoted after consultation. The Medicare breast implant removal guide explains the items in full.
How surgeons try to prevent it
Prevention starts at the original augmentation:
- choosing an implant whose width suits the chest
- preserving the attachments over the breastbone
- avoiding over-release of the inner pocket
Pairing a very narrow cleavage with wide implants carries a higher risk, and that trade-off is worth discussing before surgery. The breast augmentation page covers implant planning, and the implant size and shape guide explains how implant width is matched to the chest.
Consultation requirements
The Medical Board of Australia’s cosmetic surgery guidelines apply to symmastia correction.
- Referral: required, preferably from your usual GP, or from another GP or specialist medical practitioner.
- Consultations: a minimum of two before surgery.
- Screening: every patient is screened for psychological factors, including body dysmorphic disorder.
- Cooling-off: after the second consultation and signed consent, a cooling-off period of at least seven days applies before surgery can be booked or a deposit paid.
- Patients under 18: the cooling-off period is at least three months, with a mandatory independent psychological evaluation.
Frequently asked questions
Why does symmastia happen?
After breast augmentation, symmastia happens when the implant pockets extend too far toward the midline and the skin over the breastbone separates from the bone. Implants that are too wide for the chest, over-release of the tissue attachments over the breastbone and thin soft tissue all increase the risk. A rarer congenital form occurs without implants, where a web of tissue crosses the breastbone.
What does symmastia look like?
The gap between the breasts narrows or disappears, and the skin across the breastbone tents or lifts instead of dipping down to the bone. In more pronounced cases the breasts look like one continuous shape, and the implants may be felt near the midline. A close cleavage in which the skin stays attached to the breastbone is not symmastia.
Can symmastia be treated without surgery?
No. Once the skin over the breastbone has separated, garments and taping do not re-attach it. They are used after corrective surgery to protect the repair while it heals. Correction is surgical and rebuilds the inner wall of each implant pocket, sometimes with a new pocket, internal support or narrower implants.
Does Medicare cover symmastia correction?
Generally not. Items 45553 and 45554 cover replacing implants only after rupture, migration of prosthetic material or symptomatic capsular contracture, and symmastia is not named in either. Unless the original implants were placed in the context of breast cancer or a developmental abnormality, they also require intra-operative photographs showing that removal alone would leave an unacceptable deformity. Private health cover depends on your policy, and fees are quoted after consultation.
Can symmastia come back after correction?
Yes, recurrence is possible, because the repair relies on tissue that has already stretched. The risk is higher with thin tissue over the breastbone and with larger implants. Narrower implants, reinforcement of the repair and wearing the support garment as advised are all used to lower that risk, but none removes it entirely.
Dr Scott J Turner is a Specialist Plastic Surgeon (FRACS) consulting in Sydney and Brisbane. A GP referral is required before an initial surgical consultation under the current Medical Board of Australia framework. If the gap between your breasts has narrowed, or the skin over your breastbone has changed after augmentation, contact the practice to arrange a consultation. Bringing your implant records and operation notes assists the assessment.
