Breast Implant Placement Over versus Under Muscle: Advanced Art of Cosmetic Surgery

Advanced Art of Cosmetic Surgery: Thomas M. DeWire, MD, FACS, Surgery Center and Spa, 3974 Springfield Road, Glen Allen, VA, 23260, Richmond, Virginia, USA

Advanced Art of Cosmetic Surgery

Thomas M. DeWire, Sr., MD, FACS

Specializing in Cosmetic Plastic Surgery

Body Contouring

Anatomy of Chest Wall and Breast Implant Placement Over or Under the Muscle

Chest Wall Anatomy and the relationship to Breast Implant Placement:
The final outcome and shape of breasts after implant enlargement or Augmentation Mammaplasty is in large part determined by the relationship of the implants to the pectoralis muscles of the chest wall. Implants can either be placed above (OVER) the pectoral muscles, or beneath (UNDER) the muscles. Furthermore, the route of placement of implants under the muscle also determines whether the implant is totally covered or only partially covered by muscle when it is placed in the sub-pectoral plane. A number of consequences may result according to the		position and route of placement of implants, and some of the potential complication risks of Breast Augmentation can thus be altered by adhering to certain principles of implant placement when feasible. These include limiting risk of capsule contracture, limiting the "round" look of implants, preventing visible rippling or wrinkling of the implants, preventing "bottoming out" of the implants, and most importantly, limiting compromise of Mammography after augmentation. An example of "bottoming-out is seen by following this LINK.

Breast Implants Over the Muscle:

The Photos at left show implant placement over the muscle in the sub-glandular position, completely in contact with the breast tissue. The result of implants over the muscle provides a round augmented look in many patients, but many women prefer the round and somewhat less natural look. In the "over" approach the implants are inside the breast. Advantages are ease of the surgery, which can be accomplished by almost any surgeon, avoidance of mastopexy in mild ptosis (although it usually makes the ptosis worse later), less post-op discomfort, since only skin and fat are cut. This approach allows insertion of oversize implants, which is again what some women want. Disadvantages are marked interference with mammograms (about 40% obstruction - see reference below), clear visibility and feel of implant edges, visible and palpable rippling of the skin over the implants, especially with any textured implants, higher rate of capsule contracture, high rate of later implant downward migration or "bottoming-out", and difficulty correcting later posts problems when they occur. For the above reasons I seldom recommend implants over the muscle anymore.

Breast Implants Partially Under the Muscle:

Photos at left show partial submuscular implant coverage with implants placed under the muscle via either an areola (nipple) incision or an inframammary crease incision, thus disrupting the muscle support fascia at the lower pole of the implant to allow it to enter the space under the muscle. With this approach the implants are mostly behind the breast. This approach has the Advantages of mostly separating the implants from the muscle, facilitating unobstructed mammography, a more natural look with a soft transition from the flat of the upper chest wall to the round shape of the implant, much less visibility and feel of the implant edges, usually no rippling (except textured implants), and low risk of capsule contracture, as long as the implants have not been contaminated by ductal germs while being passed through the breast tissues. Disadvantages include a bit more discomfort early post-op, technique a bit more difficult than over the muscle, and the loss of the lower pole support fascia which leave the implants supported by the same weak skin tissues as implants over the muscle, leading to later downward bottoming-out of the implants in a few patients as is frequently seen in implants over the muscle.

Breast Implants Completely Under the Muscle:

Complete implant muscle coverage is shown at left with intact muscle fascia supporting the lower pole of the implant. This support fascia is the extension of the muscle envelope from the pectoralis muscles to the abdominal rectus muscles, and the finger shaped serratus anterior muscles to the sides, and is a stout collagen sheet which stretches slowly after implant placement, but provides reliable long-term internal bra-like support to prevent "bottoming-out". With this approach the implants are totally behind the breast. Complete muscle coverage of the implant, without cutting through the muscles, can only be achieved by Trans-Axillary approach, entering the space under the muscle where it lies closest to the skin in the anterior axillary fold. The Advantages of this approach are ease of placement, natural breast shape no implant visibility, no rippling of the implant surface (except textured implants in thin women), lower capsule contracture risk, since the breasts are completely separated from the implant, and no ducts with germs are damaged while placing the implants, low mammography interference, good internal support, and no scars on the breast. Disadvantages are the difficulty mastering the procedure, thus it is not available from all surgeons, muscle discomfort post-op, and implants which tend early to be a bit full superiorly, until the support fascia stretches. This is my favored technique for the majority of patients.

Comparison of various implant positions:

Issue	Implant Location
Issue	Over Muscle	Partial Under Muscle	Complete Under Muscle
Mammography	Marked interference even with Eklund distraction technique	Minimal interference with Eklund distraction technique	Minimal interference with Eklund distraction technique
Capsule Contracture	Highest risk	Lower risk	Lowest risk
Rippling	Highest risk especially with any textured implants	Lowest risk even with textured implants	Lowest risk even with textured implants
Natural Appearance (not desired by all patients)	+/-	Likely	Likely
Implant Bottoming out	Frequently seen - leads to inframammary scars riding up onto the breast	Frequently seen - leads to inframammary scars riding up onto the breast	Rarely seen
Use in presence of borderline sag	May correct sag in short term, but usually requires later ptosis repair because breast support ligaments (of Cooper) are cut	May correct borderline sag but may require immediate or later mastopexy	May correct borderline sag by pectoral sweep maneuver, but may require immediate or later mastopexy
Late Sag requiring repair	Frequently seen especially if over muscle was done to try to "fix" sag	Less frequent, but may be needed after pregnancy	Less frequent, but may be needed after pregnancy