In Breast Augmentation, Where Is The Breast Implant Placed?
As I am often asked this question by patients, here is an explanation and also the reason surgeons can sometimes be hesitant to offer advice as to which placement is best until a consultation is arranged for the surgeon to examine the patient.
Let’s start with the anatomy first
Looking at the anatomy of the breast, immediately behind the level of the breast tissue is known as the subglandular plane. At this level, there is the Pectoralis Major muscle running obliquely from the sternal margin upward towards the clavicle and the shoulder. The triangular fan shaped muscle covers the base around the upper two thirds, meaning there is no Pectoralis muscle behind the inferior-lateral part of the breast. Behind the Pectoralis muscle are the ribs and intercostal muscles and this plane is known as the submuscular or sub-pectoral plane.
If a breast implant is placed in this level (subglandular), it means the implant is only partly covered by muscle in the upper-medial half of the breast/implant. If a larger implant is placed, the inferior and part of the medial attachment of the muscle may need to be detached in order to accommodate the implant. More recently, a new plane is used for implant placement and this is known as the sub-facial plane. The fascial layer is a layer of fibrous tissue between the muscle and the breast tissue to accommodate movement.
What is the difference between Subglandular placement and Subpectoral /Submuscular placement?
If a patient already has a reasonable amount of breast tissue, placing the implant in the sub glandular plane in front of the muscle is perfectly reasonable. It allows for a more natural movement as breast tissue is naturally in front of the Pectoralis muscle and not behind. With ageing, breast tissue does descend and with the implant lying in front of the muscle, it will descend along with the breast tissue.
Another group of patients that benefit from having the implant placed in the sub glandular plane are those with some small degree of ptosis and a long distance between the nipple and inframammary fold. In this case, if the implant is placed behind the muscle, as opposed to in front, it may sit in a position higher than expected and with that, the nipple will not be sitting at the projecting point but below giving a ‘double bubble’ appearance.
I prefer the term sub-pectoral as the implant is placed behind the Pectoralis major muscle. It is important to appreciate that the infra-lateral part of the implant is not covered by the muscle and the implant is just behind breast tissue. Some people confused the term submusclar where the infralateral aspect is also covered by another muscle (Serratus). This is rarely done in aesthetic breast augmentation.
The major benefit of subpectoral placement is the additional coverage the muscle provides in the upper pole, particular in a thin patient with insufficient breast tissue. In round implants, the muscle will covered and mask the rippling appearance and in anatomical implants, the muscle covers the harder edge.
The second benefit is that in smaller implants, the lower muscle insertion in the ribs provides additional support to the implant. This will hopefully negate the gravitational force on the additional weight to the breast. However, in cases where larger implants are being used, the inferior insertion of the muscle may need to be divided and therefore less helpful. In some cases, the free edge of the muscle can exaggerate the animation effect of muscle contraction.
In patients with strong and bulky Pectoralis Major muscle, the upper lateral quadrant may appear too bulky. In patients with lax skin and soft tissue, the breast tissue may slide below the level of the implant protected by the muscle. In patients where the Pectoralis muscle attaches laterally, the midline gap may appear wider and less aesthetic pleasing.
So Why Does it Matter?
As you have read above, there are a variety of reasons why your surgeon may suggest a specific procedure best for one patient and not another.
Some surgeons may even place the implant underneath the muscle fascia which is a thin layer lying on top of the Pectoralis major. Others may even split the Pectoralis muscle, meaning the upper pole of the implant is covered by the muscle while the lower part of the implant lies on top of the muscle. This avoids dividing the lower muscle fibres and reduces the risk of animation and high placement of implant in patients with ptosis. This is known as ‘Dual plane’ but others have used the same term for subpectoral placement of the implant with additional release of the glandular tissue from the muscle meaning ‘dual plane’ dissection.
In essence, there are merits to all the techniques and ultimately where the implant is placed does not significantly affect the final aesthetic appearance of the breast augmentation in the majority of cases. However as you can see, there is an importance in an examination and consultation with your surgeon.