According to BAAPS breast augmentation is the commonest surgical procedure for cosmetic reasons within the UK. One of the commonest questions patients ask is whether to place implants above or under the muscle.
Historically it has been perceived that implants under the muscle may lead to less palpability, rippling and visibility in the upper pole compared with implants above the muscle. Historically there has been a trend to place breast implants under the muscle and more recently into a dual plane position.
As more cohesive breast implants have been developed the increased cohesion of the silicone has reduced the problems of palpability, rippling and visibility. Anatomical implants are also now widely available, where the upper pole that could also sit under the muscle has less volume than the lower pole, meaning that the chance of palpability, rippling and visibility in the upper pole can be further reduced. There has therefore more recently been a trend to place anatomical cohesive silicone gel implants in the subglandular plane.
It is well known that the placement of implants above the muscle in the subglandular plane allows the implants to be placed closer to the midline – a position that aids cleavage. Patients with subglandular implants describe the implants feeling more like a breast whereas implants under the muscle can feel more fixed in position with less mobility. It is believed that implants under the muscle are also more prone to malposition.
A recent study from Brazil has assessed the effect of implants in the subglandular plane vs the dual plane. They assessed the volume changes of the skin, breast and muscle as a result of placing the implants in different planes using MRI imaging at various time intervals. They have shown that 12 months following breast augmentation that implants in the subglandular plane lead to a 22% reduction in glandular volume with no reduction in muscle volume. On the other hand implants under the muscle in a dual plane position showed a 14.5% reduction in glandular volume 50% reduction in muscle volume with no reduction in glandular volume. This is due to atrophy of the pectoralis major muscle.
Roxo AC1, Nahas FX, Salin R, de Castro CC, Aboudib JH, Marques RG. Volumetric Evaluation of the Mammary Gland and Pectoralis Major Muscle following Subglandular and Submuscular Breast Augmentation.
Plast Reconstr Surg. 2016 Jan;137(1):62-9.