Surgical Anatomy and Evolution of Techniques

Early techniques of axillary augmentation accessed the implant pocket using scalpel and scissor dissection techniques.^1,2 A significant number of surgeons continue to use blunt, blind dissection techniques in some areas of the pocket for both retromammary and retropectoral pocket dissection, despite the availability of endoscopic instrumentation that can eliminate blunt dissection.^1–12 For the past 15 years, the author has completely eliminated all blunt dissection for submammary and subpectoral augmentations, significantly reducing bleeding and tissue trauma to improve patient recovery in axillary augmentation.

Surgical Anatomy for Axillary Augmentation

A detailed knowledge of the neurovascular anatomy of the axilla is essential to avoid damaging vasculature and the brachial plexus, to avoid damage to intercostobrachial and medial brachial cutaneous nerve branches in and near the axillary fat pad, and to preserve vascularity and innervation to the pectoralis musculature during surgical access for axillary retromammary, partial retropectoral, and dual plane augmentation.

The most important priorities for the surgeon during surgical access to the pocket are: (1) optimal incision location and length, (2) completely avoiding any dissection into the axillary fat to avoid damaging branches of the intercostobrachial and medial brachial cutaneous nerves, (3) locating the incision in the lateral pectoral fascia at 90 degrees to and anterior to the axillary skin incision, (4) avoiding bleeding from cutaneous branches of the posterior humeral circumflex artery and vein that course anteriorly over the lateral edge of the pectoralis major, (5) precisely defining the desired plane of pocket dissection before proceeding, and (6) entering the pocket (submammary or subpectoral) in an inferomedial direction to intersect the halfway point of a line between the midclavicular point and the nipple.

More common sensory compromises in the axilla and upper arm occur when the surgeon dissects into the axillary fat, inadvertently damaging branches of the intercostobrachial or medial brachial cutaneous nerves, causing upper inner arm anesthesia or paresthesias

Figure 12-1, A, illustrates pertinent surgical anatomy of the axilla in a fresh cadaver dissection. Although the axillary artery, vein, and brachial plexus lie superior and deep to the access plane for axillary augmentation, suboptimal retractor positioning or inappropriate dissection into the fat of the axilla can damage any of these structures. More common sensory compromises in the axilla and upper arm occur when the surgeon dissects into the axillary fat, inadvertently damaging branches of the intercostobrachial or medial brachial cutaneous nerves (Figure 12-1 A, B), causing upper inner arm anesthesia or paresthesias.Chapter 4 presents additional, detailed descriptions and illustrations of surgical anatomy related to axillary augmentation.

Figure 12-1A Surgical anatomy of the right axilla. Branches of the intercostobrachial nerve (ICBN) and medial brachial cutaneous nerve (MBCN) course through the fat pad posterior to the tunnel for access that lies immediately posterior to the Army–Navy retractor at top. The brachial plexus (BR PLEX) and axillary artery and axillary vein (AX VEIN) course just deep and posterior to the tunnel. Surgeons should limit all dissection to the area of the small black dotted line rectangle at the top of the photo at far right.

Figures 12-1B Locations of the medial brachial cutaneous nerve and intercostobrachial nerves that pass through the axillary fat pad.

A key principle is to avoid any dissection whatever within the axillary fat pad, incising the lateral pectoral fascia or deep subcutaneous fascia directly over the lateral border of the pectoralis major, and entering a submammary, subfascial, or subpectoral pocket via a tunnel that is located anterior to all critical structures in the axilla

Surgeons can completely avoid damage to neurovascular structures in the axilla by strictly adhering to specific landmarks and principles that are detailed later in the techniques section of this chapter. A key principle is to avoid any dissection whatever within the axillary fat pad, incising the lateral pectoral fascia or deep subcutaneous fascia directly over the lateral border of the pectoralis major, and entering a submammary, subfascial, or subpectoral pocket via a tunnel that is located anterior to all critical structures in the axilla (Figure 12-1A). During preoperative marking, surgeons can replicate the red line inFigure 12-1A on the skin, 1 cm posterior to and parallel to the lateral border of the pectoralis. Keeping all deep dissection anterior to this line avoids damaging the structures described previously. Superficial skin edge undermining for access and mobility, described later in more detail, does not risk damage to key structures.Figure 12-1B illustrates the relational anatomy of the medial brachial cutaneous nerve and intercostobrachial nerves to the breast and axillary fat pad.

Figure 12-2 illustrates relational anatomy of the access tunnel to neurovasculature and musculature of the chest. In the tunnel for access, the dissection plane to enter the subpectoral space is immediately beneath the pectoralis muscle. Any dissection more posteriorly in the axillary fat risks damage to intercostobrachial nerve branches and branches of the lateral thoracic artery and vein that course in a superior–inferior direction in the fat on the floor of the tunnel. The optimal direction from the skin incision to enter the subpectoral pocket is in an inferomedial, not directly medial, direction to minimize risks of damage to branches of the thoracodorsal artery or vein.

Figure 12-2 Medial to lateral view of left chest wall with pectoralis major muscle retracted laterally. The gloved fingertip is visible in the tunnel for axillary access, and the green arrow indicates the direction in which the surgeon should first enter the subpectoral plane for pocket dissection. The intercostobrachial nerve (ICBN) is located immediately posterior to the tunnel, and the thoracodorsal artery and vein (TDA, V) are located in the fat pad on the undersurface of the pectoralis major muscle cephalad and anterior to the plane of the tunnel.

Figure 12-3 illustrates the musculofascial anatomy of the right chest with breast, skin, and subcutaneous tissue reflected. A blunt dissector beneath the pectoralis has been pushed inferiorly to demonstrate that subpectoral blunt dissection inferior to the pectoralis passes deep to the deep subcutaneous fascia lateral to the lateral border of the rectus sheath, detaching the deep subcutaneous fascia from its fusion with the lateral rectus sheath. Under direct endoscopic control, surgeons can divide origins of the pectoralis inferiorly to create a dual plane type 1 pocket, or leave the pectoralis origins intact for a partial retropectoral pocket. When relocating the inframammary fold inferiorly without dividing the pectoralis along the inframammary fold, dissection below the inframammary fold usually elevates the inferior-most origins of the pectoralis in continuity with deep subcutaneous fascia lateral to the rectus sheath.

Figure 12-3 When bluntly dissecting a subpectoral pocket via the axillary approach, the dissector passes deep to the pectoralis major. As it sweeps from medial to lateral, at the lateral border of the rectus sheath, the dissector avulses the attachments of the deep subcutaneous fascia to the lateral border of the rectus sheath.

Based on dissections after performing axillary augmentation in fresh cadavers,^7,8 the author’s findings contradict findings of other surgeons who presented or reported that blunt dissection predictably divided the main medial origins of the pectoralis major muscle along the sternum and along the inframammary fold and that blunt dissection could predictably elevate the serratus muscle laterally.⁹ Instead, the author found it virtually impossible to divide the main body of pectoralis origins medially with blunt dissectors, that inferiorly along the inframammary fold the blunt dissector divided pectoralis origins off the fourth and fifth ribs and passed deep to the deep subcutaneous fascia below the inframammary fold, and predictable blunt blind elevation of the serratus muscle intact and in continuity with the pectoralis via the axillary approach is impossible. These findings were further confirmed when endoscopes became available by examining a bluntly dissected pocket with an endoscope.

Predictable blunt blind elevation of the serratus muscle intact and in continuity with the pectoralis via the axillary approach is impossible

Clinical Experience

From 1977 to 2005, 690 patients aged 19 to 64 years (median age 31 years) chose the axillary augmentation approach for breast augmentation. Eighty-four patients had implants placed in the retromammary (RM) pocket location, 294 patients had partial retropectoral (PRP), and 312 patients had dual plane (DP) placement. From 1977 to 1992, blunt dissection was used to create partial retropectoral pockets (inframammary fold pectoralis origins left intact) and submammary pockets. From 1992 to 2005, all dissection was performed under direct visualization with endoscopic assistance using electrocautery dissection to create partial retropectoral pockets in 13 patients and to create dual plane 1 pockets (dividing origins of pectoralis along the inframammary fold) in 282 patients.

Beginning in 1994, a Snowden Pencer ROAM™ right angled endoscope and Ethicon Probe Plus II™ endoscopic dissector were used exclusively for pocket dissection, totally eliminating all blunt dissection in all cases.

Beginning in 1993, patients educated about all incision approaches could choose whatever incision approach they preferred according to staged, repetitive education and informed consent processes.¹⁴ Based on more extensive surgical experience and followup with axillary augmentation, the surgeon and staff more specifically informed patients of all potential nuisances, surgical control factors, and potential tradeoffs of the axillary approach beginning in 1995. A much smaller percentage of patients subsequently chose the axillary approach, with a substantial majority of patients (more than 70%) having augmentation between 1995 and 2005 selecting an inframammary approach.

Preoperative planning and implant selection after 1993 utilized dimensional and tissue based processes published in Plastic and Reconstructive Surgery.^15,16 Beginning in 1997, all patients were encouraged to immediately resume full normal activities the evening of surgery. No drains, special bras or straps, intercostal blocks, pain pumps or narcotic strength pain medications were used in any patient after 1996.

Clinical Assessment, Operative Planning, and Implant Selection

Current preoperative clinical assessment and operative planning for axillary augmentation precisely follows the methods and processes of the High Five™ System¹⁵ and the previous TEPID™ System of quantitative tissue assessment and implant selection¹⁶ that is incorporated in the High Five™ System. Clinical assessment using this system prioritizes five critical decisions and uses five simple measurements that enable surgeons to complete all pertinent clinical assessment and operative planning decisions in 5 minutes or less. All decisions of pocket location, implant size, and inframammary fold position are based on defined, quantifiable tissue parameters individual to each patient.

Choice of implant pocket location determines soft tissue coverage for the patient’s lifetime, is the most important decision in every breast augmentation, and is based on quantitative measurements of soft tissue thickness. If soft tissue pinch thickness superior to the breast parenchyma (STPTUP) is >2 cm, submammary or subfascial pocket locations are options. If STPTUP is <2 cm, pocket location options to optimize long-term soft tissue coverage are limited to dual plane¹⁰ or traditional subpectoral pocket locations, in both cases preserving intact all medial origins of the pectoralis major along the sternum to the inframammary fold junction in every case. Measurement of soft tissue pinch thickness at the inframammary fold (STPTIMF) provides quantitative criteria on which to base a decision of whether to preserve all pectoralis origins intact along the inframammary fold to assure optimal coverage. If STPTIMF is <0.5 cm, surgeons should preserve the inferior origins of the pectoralis intact along the inframammary fold, and create a traditional retropectoral pocket. When STPTIMF is >0.5 cm at the IMF, coverage is adequate to allow surgeons to divide origins of pectoralis along the fold to create a dual plane pocket. These criteria and processes resulted in zero incidence of visible traction rippling or visible implant edges in 1664 reported cases with up to 7 year followup via axillary, inframammary, and periareolar approaches.^10,12,17

If the patient requests the surgeon’s input in selecting an implant that is safest for the patient’s tissues long-term with the lowest risk of reoperation, implant selection is based on the High Five™ System¹⁵ that estimates an approximate implant volume based on quantitative measurements of individual patient tissue characteristics. This approximate implant volume is based on quantitated, measured, individual patient tissue characteristics, derived from the base width measurement of the patient’s existing breast parenchyma (BW), the stretch characteristics of the envelope (anterior pull skin stretch measurement or APSS), and assessment of the contribution of the patient’s existing breast parenchyma to stretched envelope fill (percent contribution to stretched envelope fill or PCSEF). If the patient has a specific implant size request based on a specific number of cc’s or grams, the patient must individually assume all responsibility for that decision in detailed, written, line-item informed consent documents,¹⁴ and the surgeon then considers whether that request is acceptable given the patient’s tissue characteristics and breast dimensions.

The third decision in planning is the specific type and dimensions of the implant (implant volume was determined as the second step of the High Five™ process). All current saline filled implants and all current silicone gel filled implants up to approximately 350 cc volumes can be safely and predictably inserted via the axillary approach. Larger gel implants, cohesive gel, and larger, round form stable cohesive gel implants can also be inserted via the axillary approach, but require larger incisions that extend more posteriorly where they may be more visible, require more surgical experience and skill for insertion, and entail a greater risk of implant device damage during insertion.

The fourth step in preoperative planning is defining desired nipple-to-inframammary fold distance (N : IMF) to create intraoperatively. The desired, new intraoperative position of the inframammary fold was determined subjectively by intraoperative visualization in cases prior to 1996 when the TEPID™ System¹⁶ provided a much more accurate, objective method of defining optimal fold position relative to the implant selected for augmentation. The TEPID™ System is integrated into the High Five™ System as the fourth critical decision in every breast augmentation. Specific methodology is detailed in the TEPID™ and High Five™ papers.^15,16

Implant Types

Table 12-1 summarizes implant types and sizes in the series.

Table 12-1 Implant types and sizes

Despite recent reports of inserting form stable, cohesive, anatomic gel implants (Inamed Style 410) via the axilla,¹⁷ no implants of this type were placed via the axilla by the author in the 410 premarket approval (PMA) study in the United States¹⁸ because the author feels that the axillary approach does not provide the most optimal control for insertion and consistent, predictable positioning of these devices, and adds additional risks of implant damage during insertion. Since 1992, the patient, not the surgeon, chooses implant type (except in complicated cases) using our previously described patient education and informed consent process.¹⁴

Preoperative Marking

Axillary incision location is critically important to minimize scar visibility. Optimal incision location is in the hairbearing skin of the deepest apical portion of the axillary hollow, with the anterior-most extent of the incision posterior to the lateral border of the pectoralis (Figure 12-4). Incision length can vary from 2 to 6 cm to accommodate varying instrumentation and implants. Axillary scar quality and minimizing damage to implants during insertion are far more important than incision length. Average ideal incision lengths of 4–5 cm minimize instrument trauma to skin edges and damage to implants from excessively short incisions. Although it is technically possible to insert inflatable implants through axillary incisions as short as 1.5 cm, incision lengths of 4–5 cm provide increased control and decreased skin edge trauma for surgeons who use state-of-the-art instrumentation and techniques. Scar visibility relates far more to scar quality compared to scar length, and an additional centimeter of incision length can dramatically improve control while minimizing trauma to skin edges and damage to the implant shell. Scar location (determined by incision placement) is the factor that most affects axillary scar visibility.

Figure 12-4 Left: The surgeon places a dot in the apex of the axillary hollow and outlines the lateral border of the pectoralis major muscle. Middle: The surgeon then draws a line through the dot from anterior to posterior, keeping the incision line high in the axillary hollow, not necessarily paralleling or within an axillary crease line. Right: With the patient’s hand on her hip, no portion of a properly located incision line is visible.

With the patient standing with her hands on her hips and flexing the pectoralis to define its superolateral border and deepen the axilla, the surgeon marks a line vertically over the middle of the lateral protruding border of the pectoralis (Figure 12-4, left), and places a dot in the apex of the hairbearing skin of the axillary hollow. Beginning at least 1 cm posterior to the lateral border of the pectoralis, the surgeon marks the incision line coursing superiorly and posteriorly through the dot in the apical hairbearing skin of the axilla. Paralleling skin creases in the axilla is not necessary, but it is important to keep the posterior part of the incision high in the axilla to minimize visibility. The objective is to create at least a 4 cm incision that begins posterior to the lateral border of the pectoralis and remains in the axillary apical hollow. Although shorter incisions are technically possible, they limit retractor width and visualization and encourage skin edge trauma that compromises scar quality.

After placing a dot at the sternal notch and xiphoid, and connecting the two with a series of vertical dots to define a visual midline of the sternum, the surgeon then places additional dots 1.5 cm lateral to each of the midline dots to define the maximal medial extent of pocket dissection that prevents inadvertently disrupting medial perforators that are usually located 1 cm lateral to the midline. Maintaining at least a 3 cm intermammary distance in all cases minimizes risks of medial perforator disruption, compromised medial soft tissue coverage, visible implant edges medially, visible medial traction rippling, and synmastia.

After marking the existing inframammary fold, the surgeon places the tip of a tape measure at the nipple, lifts the nipple maximally superiorly to maximally stretch the skin of the breast lower pole, and then at the 6 o’clock position, marks the desired, new nipple-to-inframammary fold distance recommended by the TEPID™/High Five™ System by placing a dot. If the desired new fold level is below the existing fold, the surgeon outlines the desired, new inframammary fold below the existing fold, and in the process, corrects any fold contour irregularities.

Additional topographic markings can include the desired lateral border of the implant pocket, taking into account the desired base width of the implant selected, its base imprint over the curvature of the chest wall, the compliance of the patient’s soft tissue envelope, and the projection of the implant. All of these variables make defining a lateral pocket border nothing more than an estimate that should always be conservative in a medial direction to avoid overdissection of the lateral pocket.

Anesthesia and Local Anesthetic Instillation

Chapter 14 is devoted to preoperative care, anesthesia, and postoperative care. Optimal, state-of-the-art breast augmentation and optimal recovery require general anesthesia and muscle relaxants. General anesthesia can reduce the amount of intraoperative sedative and narcotic drugs a patient requires while enabling surgeons to perform a more accurate, controlled operation and dramatically reducing patient recovery times, enabling axillary augmentation patients who have had a general anesthetic to leave the surgical facility with an ASPAN score of 10 within 45 minutes of their transfer to recovery following the procedure.¹³ Instillation of a vasoconstrictive agent along the incision line may reduce dermal bleeding, but instillation of local anesthetic into any other area of the breast or pocket is unnecessary and has the following potential risks: (1) multiple small hematomas within the breast parenchyma, (2) increased electrical resistance in all infiltrated tissues that decrease the efficacy of electrocautery dissection, and (3) increased risks of pneumothorax with deeper infiltration or intercostal blocks. Intercostal blocks, instillation of local anesthetic agents into the pocket, and pain pumps are totally unnecessary for patient comfort postoperatively if surgeons apply proved processes that predictably deliver 24 hour recovery.¹

Surgical Techniques and Surgical Scripts for the Axillary Approach

Specific details of surgical technique enable surgeons to predictably assure over 90% of patients that they can return to full, normal, non-aerobic activities within 24 hours following either axillary subpectoral or submammary augmentation for the first time in the history of breast augmentation.³ This rapid recovery is remarkable, because it completely redefines the patient experience in modern augmentation mammaplasty, and this level of recovery is predictable using inframammary, periareolar, and axillary incision approaches. Rapid recovery and return to normal activities within 24 hours is impossible without dramatically reducing tissue trauma and bleeding. The following techniques, combined with optimal anesthetic management, predictably allow surgeons to deliver their patients a completely redefined experience in breast augmentation.

Table 12-2 is a detailed script for inframammary augmentation derived from process engineering principles analysis¹ that defines virtually every essential movement of every person in the operating room. Pilots, astronauts, and many business and industrial personnel routinely use defined processes and derived scripts or checklists for training and to optimize performance of numerous processes. Electronic files of this script are available in the Resources folder on the DVDs that accompany this book. After distributing this script to operating room personnel for review, surgeons can place these documents on a laptop computer in the operating room and have a designated person read steps of the operation in sequence. This simple process can dramatically reduce unnecessary and time wasting maneuvers, dramatically reducing operating times and patient recovery times.¹ This script is also a valuable learning tool for plastic surgery residents.

Premedications and Anesthesia

The preanesthetic and anesthetic regimens and printed protocols that allow patients to be out to dinner the evening of surgery and resume full normal activities within 24 hours are available in a previous publication¹³ and in the Resources folder on the DVDs that accompany this book. All axillary augmentation patients follow exactly the same postoperative management regimen as inframammary and periareolar approach patients. Minimizing sedative and narcotic medications pre-, intra-, and postoperatively is critical to early return to full activities, and requires that the surgeon minimize surgical trauma and bleeding. Total narcotic doses intraoperatively average 2–4 cc of fentanyl. In recovery and stepdown, total narcotic doses are 25 mg of Demerol in two divided doses preceded by 6.25 mg of Phenergan administered 3–4 minutes prior to the Demerol. Using this regimen, nausea and vomiting have been virtually non-existent. Details of dosing and timing of doses are included in the previously referenced publication.¹³

All patients have general endotracheal anesthesia with muscle relaxants intraoperatively to minimize retraction forces and trauma to the pectoralis muscle while relaxing the pectoralis to allow optimal visualization and control.

Surgical Instrumentation

Endoscopic visualization and dissection substantially increase control and accuracy in axillary augmentation and render blind, blunt dissection techniques unnecessarily traumatic and obsolete. A variety of effective endoscopic instrumentation is available to surgeons. Instrumentation optimizes flexibility, accuracy, control, and efficiency when a minimum number of instruments and minimum number of instrument changes and moves provide maximum exposure and control. After using all instrumentation that was available in the 1990s, the author integrated available instrumentation that was most effective with new designs that better optimized flexibility, accuracy, and control.

Most surgeons perform axillary endoscopic dissection through a single port. Conventional, straight endoscopes with a camera mounted in line with the endoscope partially obstruct optimal access for dissecting instrumentation that the surgeon introduces alongside the endoscope. The ROAM™ right angled endoscope–retractor system (Figure 12-5) was designed to (1) alleviate obstruction of the single axillary port by an in-line camera, and (2) allow rapid, omnidirectional endoscope movement independent of a retractor that provides exposure while allowing the surgeon to clamp the endoscope into the retractor when desired to free both hands for hemostatic control or delicate dissection. The ROAM™ right angled endoscope system is designed to function as surgeons are trained—establish exposure with appropriate retraction, then allow the eye (in this case, the endoscope) to roam the dissection field with a wider field of vision, constantly moving to visualize and anticipate anatomic details and neurovasculature for maximal control.

Figure 12-5 The ROAM™ right angled endoscope–retractor system consists of a specially designed retractor that incorporates smoke evacuation, and a right angled endoscope that the surgeon can manipulate independently of the retractor for bimanual visualization and dissection. The retractor also has a groove (inset photo) that allows the surgeon to attach the endoscope to the retractor if desired. This right angled endoscopic system eliminates obstruction of the single operative port by the camera and adapter that are mounted on the endoscope.