SYNMASTIA – AN UNUSUAL COMPLICATION OF AUGMENTATION MAMMAPLASTY

INTRODUCTION

Medial confluence of the breasts, or synmastia, was first described by Robert Spence in 1984 (1). The term synmastia has its origin in the Greek syn (together) and mastos (breast). Synmastia can be either congenital (2) or acquired from augmentation mammaplasty (reffered also as breadloafing, uniboob, kissing implants). Synmastia after mammaplasty is defined as unnatural communication between the breasts, created by infringement of the midline of the chest with medial movement of one or both implants and subsequent contact between both implants above the breast bone.It is probably the least common complication, which is why most plastic surgeons are not aware of the right diagnosis and treatment for this condition. Either they tell patients they do not have synmastia or they treat patients by removing implants and replacing them some time later.

From a surgical point of view synmastia happens most frequently when the surgeon excessively dissects the tissues and muscles over the sternum to further bring the breasts closer, together resulting in more cleavage. Once the implants touch each other, the natural cleavage is lost. In case of subpectoral placement the muscle can be damaged at the point where it attaches to the breast bone. Less frequently, with subglandular placement, synmastia can arise from excessive dissection of sub cutis in medial direction (3). Incomplete separation of small and large pectoral muscles can contribute to synmastia on the lateral side of the breast, while activity of both muscles pushes the implant medially. In addition, one factor can be the use of implants which are too large, or are of unsuitable shape. Synmastia is more common in patients after repeated breast operations.

Failure to adhere to proper post-operative behavior could be a cause on the part of the patient. In an effort to present full cleavage, patients wear underwear which presses breasts medially and cranially too soon. Synmastia probably occurs more often in thin women who have less fat which overlaps the sternum, and also in women with pectus excavatum. Consequently it is better to choose smaller implants in these cases.

Correction consists of removing the capsule in the area above the sternum and connecting soft tissues to the breast bone again (preferably with non-absorbing stitches) (4). In case of subglandular placement of implants we prefer to create a new cavity submuscularly. If the implants are primarily placed submuscularly it is necessary to connect the interrupted insertion of the muscle to the sternum again. It is important to expand the cavity laterally or use new implants of smaller diameter. Recurrences after correction are common, mainly due to rupture of stitches which are under pressure of the implant.

In addition, in the literature another possible method of correction is mentioned in cases of recurrent synmastia: using implants with adjustable volume retaining capsule and suture of the anterior and posterior flap of the capsule medially. Filling of the implants is performed after healing of suture repair – at a time when it has sufficient strength (5). In addition, we can find information about the possibility of correction with alloderm grafts in the literature (6).

CASE STUDY

The patient from USA, 179 cm high, weight 55 kg, with slim habitus and rather thin subcutaneous tissue, underwent an operation at our clinic. She asked for enlargement of her breast to size B/C. The breasts were asymmetric, with hypoplasia of the middle level. The left breast was smaller, and the areola was located higher and more laterally in comparison with the right – the reason was asymmetry of the chest with typical prominence of the left sternocostal joint. The patient agreed to implants size 275cc, which was recommended during the preoperative examination.

During an operation from periareolar access a cavity under the large pectoral muscle was created, and the muscle was disconnected from the 3^rd to the 9^th rib. Inside the cavity round implants were later inserted (Mentor co., moderate profile), size 275 cc. After insertion of drains, we performed suture of tissues in layers. The drains were removed after 24 hours. The patient was discharged to outpatient care after application of her own bra with breasts in good anatomical position. At a post-operative examination (7^th post-operative day), before leaving for the USA, the position of breast was still satisfactory. How-ever, at this time a slight suspicion of movement of the left implant medially was found. Patient was instructed about on-going care.

In consequent post-operative care in the USA there was a change in position of both breasts – they moved to- gether medially. That was documented by photographs sent by email. After 5 months she came for a check-up, at a time when synmastia was fully evolved and its operative correction was indicated. At this time both breasts were located medially, while the movement of the implant was more evident on the left side.

We started reoperation after preoperative drawing of the future location of new implants was performed. After we carried out extraction of the implants and cut through rather thin fibrous tissue, we enlarged the cavity for the implants laterally and cranially. Then we partially reinserted loose breast muscles into the site of their original insertion with nonabsorbent stitches. At the end of the operation we replaced the implants with verification of their new placement. (Fig. 1–4.)

DISCUSSION

Origination of synmastia in this patient can be due to several reasons including unfavorable anatomical conditions, and also to excessive effort being made to achieve symmetric placement of both implants. Distinctively prominating sternocostal joint, which affects most probably the left side of the chest and is noticeable mainly in thin women, always pushes an inserted implant more laterally in comparison with the other side. In these cases, while we try to place both implants symmetrically, the implant can move medially by excessive mobilization of sub cutis above the prominating joint and by disconnecting the breast muscle. This phenomenon can also be facilitated by insufficient room for implant made by preparation laterally and cranially.

CONCLUSION

Synmastia is an uncommon complication of breast augmentation. Prevention of its origination consists of careful preparation of the cavity for implants in a medial direction, especially in slim women where we find asymmetry of the chest with prominence of sternocostal joint. Furthermore, for these women the plastic surgeon should not be induced to use disproportionate sized implants. During the operation the muscle should not be released with sub-muscular placing above the areola or 7^th rib. With subglandular placement of the implant the edge of the sternum should not be exceeded. It is necessary not to leave fascicles of small and large pectoral muscles connected, which sometimes happens during blunt dissection, but to detach them sharply until the subcutaneous fat is visible. As with any deformation of the chest accompanied by asymmetry, it is always important to instruct the patient about this fact and to indicate the extreme unlikelihood of faultless symmetry with the augmented breast. The fact that patients should always wear correct post-operative underwear for at least 3 months after operation should of course be obvious.

Address for correspondence:

Zdenek Pros, M.D.

Na Příkopě 17

110 00 Prague 1

Czech Republic

E-mail: zdenek.pros@tiscali.cz