Breast Augmentation With Implants—Inframammary Approach

Introduction

Over the last 20 years, considerable effort has been placed on re-evaluating breast augmentation and shifting the focus away from simply volumizing the patient to a more comprehensive approach to breast augmentation. Peer-reviewed articles and prior book chapters have already stressed the critical importance of thorough patient education and informed consent and defining breast augmentation as a “process.”

It has become abundantly clear that we need to create well-informed and engaged patients who understand the limitations of their tissues and their responsibility to maintain good breast health, and to eventually replace their implants as both the implants and the patient age. Key considerations in breast augmentation should no longer focus on the “cup” size to be achieved, but rather on maintaining adequate overlying tissue coverage, matching the gel fill with the feel of the breast, the management of patient expectations, and selecting a device and a procedure that will produce long-term stable aesthetic results. The inframammary fold (IMF) incision remains the standard to which all other incisions are compared. It provides the most direct access and clear visualization to the subglandular, dual-plane, and subfascial pockets, with the potential for the least trauma and contamination. The anatomy of the IMF has been eloquently described and is a clear visual marker for defining the lower pole of the breast.

Despite considerable literature on the benefits of an IMF incision, surgeon and patient concern remains about placing a scar on the breast. Hypertrophic scars can potentially occur anywhere on the body and may be the result of poor execution, patient biologic status, or both. Few data have been published on patient preference for scar location, but a well-placed and hidden inframammary scar is far less noticeable to most patients than a periareolar scar.

The last decade has seen the introduction of new silicone and saline breast implants on the worldwide market. The specific type of gel used allows some control over the gel distribution with the shell. Each device has clear benefits and trade-offs, but more important is the effect produced by each of these factors on the soft tissues of the lower pole of the breast over time and on the IMF in particular. This chapter will focus on primary breast augmentation through an inframammary approach. Special attention is drawn to the IMF anatomy and the surgical procedure, including stabilization of the new IMF when indicated, and the short-term and long-term management of the patient undergoing breast augmentation.

Preoperative Evaluations and Special Considerations

With aesthetic breast procedures it is critically important that patients are permitted and expected to participate in the decision-making process, weighing the pros and cons of the risks and benefits of each choice. Patients do not always understand what they are told or may, in hindsight, feel as though their decision was not based on all appropriate information. Using a staged approach, surgeons and their staff may need to repeat various topics several times and require written documentation that the patient understands the choices offered. Once streamlined into a busy breast augmentation practice, this approach produces patients who understand, accept, and take responsibility for their decisions. Signing a single informed consent document before surgery does not always imply understanding. If possible, patients undergoing breast augmentation should be given a second consultation reassuring those patients who want to be part of the decision-making process that they will be given ample time to weigh all of their surgical and device options. It is most important that patients should be given sufficient opportunity to become well-informed, shared decision makers.

Historically, breast implant selection was based on the subjective desires of both the patient and surgeon. Techniques such as asking the patient to bring in a photograph to illustrate the type of breast she wants provides very little useful information from an operative planning standpoint. Similarly, the practice of stuffing implants into a bra can be extremely deceiving because this cannot simulate the stretch or fill of the existing breast and muscle tissue. Although each of these methods may contribute to a better understanding of the goals and desires of a patient, they are subjective findings that cannot compare with the capabilities of three-dimensional (3-D) imaging technology. In addition, although many surgeons and patients also use the term desired base width, the actual base width is perhaps the most critical measurable dimension that affects the long-term outcome of a breast augmentation. It is the combination of prioritizing the quantifiable measurements, while also ensuring adequate soft tissue coverage over all areas of the selected implant, that offers the potential for stable and enduring outcomes.

The final implant selection should be based on objective tissue-based planning ( Fig. 1.1A–D ), matching the feel of the breast to the cohesivity, the viscoelastic properties of the device, and the aesthetic goals of a well-educated patient.

3-D imaging technology has become an integral part of a comprehensive breast augmentation consultation. Preoperative simulations help create well-informed and engaged patients and their significant others. Several systems currently exist, including Canfield Imaging Systems (Canfield Scientific, Parsippany, NJ) and Divina (AZ3 Technologies, LLC, United States, Guatemala, and Costa Rica). These systems have become increasingly interactive, and unlike viewing other patients’ presurgical and postsurgical images, patients are given the opportunity to view their own possible outcomes before surgery. The 3-D technology reproduces the manual measurements previously obtained during the physical examination.

During the simulation, patients can view themselves from different angles and carefully examine their own anatomy, including existing asymmetries. The time spent with the patient can be invaluable in teaching what may be possible based on the patient’s specific anatomic landmarks and soft tissues. Various volumes and projections of breast implants can be demonstrated with sensational accuracy. Asymmetries in volume and shape can be addressed and possibly reduced with the use of various devices ( Fig. 1.2A–C ). Studies have demonstrated the precision of these systems in primary breast augmentation.

The breast type is the key to selecting the fill of the implant. Looser, emptier breasts may be better suited to more elastic, less cohesive devices, where the implant is not required to shape the breast. Very tight breasts may benefit from a more cohesive, less elastic gel that can produce shape over time. This is especially true for constricted base or tuberous breasts. Another way to select the implant type in breast augmentation is to use a gel fill that is similar to the feel of the existing breast parenchyma. The fundamental goal is the selection of breast implants that will prioritize long-term outcomes over short-term patient satisfaction.

3-D imaging technology is especially useful in determining the location of the IMF and incision planning. Through the simulation process, patients gain an understanding of why the width and height of a round implant or the height of a shaped implant matters. Implant selection needs to be based on the individual chest wall anatomy and desired outcome. Placing an implant too high or positioning the implant too low on the chest during a simulation can also demonstrate potential malposition deformities or explain the effect of an oversized implant over time ( Fig. 1.3A–D ).

The use of prophylactic antibiotics for procedures that breach the skin or mucosa is also recommended to prevent endogenous bacteria from reaching an implanted device for as long as the patient has a breast implant. Finally, patients undergoing breast augmentation will all continue to age, gain and lose weight, birth children, breastfeed, and eventually go through menopause. A close and enduring relationship with our patients ensures optimal results, sound breast health, and years of happiness for our patients and our practices.

Surgical Techniques

Anatomy and Function of the Inframammary Fold

The IMF anchors the lower pole of the breast to the chest wall and can be almost absent in cases of severe hypoplasia of the breast. Cadaver studies through the 20th century described the IMF as a crescent-shaped ligament between the skin and the anterior surface of the pectoralis major muscle. The structure has further been described as both a ligamentous structure and a dense collagen network, functioning as a zone of adherence between the dermis and underlying pectoralis fascia. ^,

More recent cadaver studies have identified a network of fascial condensations that connect the deep muscle fascia to the anterior breast capsule—termed the triangular fascial condensation ( Fig. 1.4 ) A second zone of horizontal ligaments arises from the deep fascia of the rectus abdominus to the Scarpa fascia and inserts into the inferior limit of the fold. The precise relationship between the inferior border of the pectoralis major muscle and the IMF has been further studied, and the actual IMF is visually identified approximately 2 cm below the inferior pectoralis origin.

In addition to the central portion of the IMF there are medial and lateral inflection points of the IMF and these are located medially, where the breast meets the sternum, and laterally, where the breast meets the anterior axilla. Manual traction applied on the breast medially and laterally can easily identify the endpoints of the breast in a thin patient. More careful analysis may be required in patients with more body fat, because medially the two breasts may meet and laterally the breast may blend into the posterior axilla and back. The same maneuvers are used to more accurately calculate the true breast base width.

Systems to Determine New Intramammary Fold

Biodimensional tissue–based systems, first introduced by Tebbetts, have been elaborated upon by numerous surgeons (see Fig. 1.1A–D ). These systems are widely used because they are suitable for a variety of both shaped and round devices; they include the High Five decision support system, defined by Adams ; the Akademikliniken Method, described by Hedén ; and the Randquist method. Newer published systems, including the ICE (implant dimensions, capacity of lower pole, excess skin required in lower pole) principle, attempt to simplify some of the more elaborate formulas.

The common thread between the three leading systems is that the larger the base width–diameter, projection, volume, and lower ventral curvature (LVC) of the device selected, the longer is the nipple-to-fold distance required. The concept behind using the implant’s LVC ( Fig. 1.5 ) is that this number can be used to help calculate the ideal amount of skin required between the nipple and the IMF. The LVC is calculated as the surface distance from the implant’s ideal nipple position down to the lower implant border. Several manufacturers are now providing this information for all of their implant models. ^,

Yet another system, the simplified evaluation system, is a preoperative assessment tool for determining the new IMF based solely on the vertical dimension of the implant, not on the breast base width or volume of the implant. The authors also do not adjust their calculations for varying implant projections. This system does not account for the lower pole skin stretch or compliance, and there are known long-term consequences of placing a high projecting, larger volume implant into a looser skin envelope.

Many approaches support the logic of preoperatively calculating the planned IMF location based on (1) the base width, height, or diameter and the projection of the selected implant; (2) the quantity of gland and parenchyma present; (3) the quality of tissues and skin stretch; and (4) the shell and viscoelastic properties of the selected device. All preoperative marking systems must take into account these variables if they are to produce predictable long-lasting outcomes. Measurements of the existing nipple-to-fold distance should always be taken on stretch to stimulate the effect of the implant on the tissues ( Table 1.1 ).

TABLE 1.1

Comparison of Systems Used to Identify the Inframammary Fold Position

System	Measurements	Formula	Fudge Factors-limitations	Round/Shaped
Hedén	Implant base width/diameter and projection determine the location of new IMF N/IMF = LVC + Distance to be added for additional glandular tissue	Akademikliniken method: NM with arms up-½ implant height = Distance in to lower IMF LVC + N to ILP−½ implant height = New length required	LVC = Lower ventral curvature of the implant (point of maximum projection to implant lower border (ILB) Considers aesthetic outcome over time and variable effect of gel fills on final outcome	Can be used for both round and shaped: 50:50
Malucci ICE	Implant height and projection determine location of IMF Existing N/IMF on stretch = Capacity (C)	I−C = E I = Implant dimensions (height/2 + projection) C = Capacity of lower pole E = Excess skin required in lower pole	Considers aesthetic outcome over time and proportion of upper to lower pole fill Implant characteristics (height and projection), breast base width, and N/IMF on stretch determine amount of skin that must be recruited	Can be used for both round (50:50) and shaped (45:55)
Tebbetts Adams High-Five	Implant base width determines location of IMF	Implant case width determines N/IMF distance: 200 = 7.0 250 = 7.5 300 = 8.0	Critical relationship between the breast base width and N/IMF Implant volume and projection determine effects on tissues over time	Can be used for both round and shaped devices
Randquist	Base width of implant and tissue characteristics	Implant base width 11.0 = 7.5 cm 11.5 = 8.0 cm 12.0 = 8.5 cm 0.4 cm upper pole + 0.5 cm Tight envelope + 0.5 cm Loose skin/parenchyma – 0.5 cm	Requires measurement of existing N/WF on maximum stretch Precise pocket dissection and IMF repair to maintain implant position over time	Round and shaped Works best with highly cohesive gels that expand lower pole over time
Bouwer et al.	Uses Pythagorean theorem to determine location of IMF	${\alpha }^2+{\beta }^2+{\gamma }^2$ α = ½ implant height β = Implant projection γ = Areola-to-IMF distance in cm	Based on average areola diameter of 4 cm, and average breast thickness of 2 cm Standardized system with limited regard for tissue characteristics and long-term aesthetics	Round only
Atiyeh et al.	Simplified system uses calculated change in nipple position preoperatively + implant width or height	SN-N 1 = Measured with arms at side SN-N 2 = Measured arms horizontal ½ implant vertical height– round LVC: anatomic	New IMF determined by change in nipple position + ½ implant height. Lowers both IMFs the same distance and may lead to significant malposition over time	Can be used with both round and shaped

ILB, Implant lower border; ILP, implant lower pole; IMF, inframammary fold; LVC, lower ventral curvature; N, nipple; SN, sternal notch.

Finally, not all implants perform the same way over time. Smooth round gel implants can vary in the degree to which they descend and stretch the skin and capsule of the lower pole over time. This is due in part to their smooth surface, the viscoelastic properties of the gel, and the thickness of capsule generated in response to the shell characteristics. Care should be taken with some of the newer, softer, more viscoelastic gel implants with smooth surfaces to control the pocket dissection and specifically reinforce the IMF if lowered, to avoid inferior malposition. A good general rule, however, is that if the calculated nipple-to-fold distance for the planned implant is greater than the patient’s preoperative nipple-to-fold distance, the IMF needs to be lowered and reinforced. If the fold requires lowering more than a centimeter, with the exception of constricted base breasts or tuberous breast deformities, a smaller volume or base width implant may need to be selected. Perhaps most importantly, if the fold is lowered, it should always be fixed with a layered repair. The final breast position and lower pole contour are not usually realized until at least the 6-month visit and perhaps at 1 year in some patients ( Fig. 1.6A–E ).