Abdominoplasty

One of the most commonly performed aesthetic procedures, abdominoplasty, in which excess skin and fat are removed from the abdomen, has undergone significant evolution over the past several decades. Kelly was one of the first surgeons to attempt to correct excess abdominal skin and fat. ^{[1, 2]} Using a transverse incision, he was able to resect a 7450-g panniculus measuring 90 X 31 X 7 cm. Since that time, numerous variations have been suggested. Thorek was the first to devise a procedure that preserved the umbilicus. ^{[3, 4]}

In 1967, Pitanguy published a report of 300 abdominal lipectomies, ^[5] followed by Regnault, who published the W technique for abdominoplasty in 1972. ^[6] In 1973, Grazer was one of the first authors to describe the so-called bikini line incision, ^[7] and in 1967, Callia described a low incision that extended below the inguinal crease. ^[8] This also appears to be the first report of aponeurotic suturing. When the Saint Tropez bikini (with a very low waistline) was fashionable, the abdominoplasty incision was nearly horizontal in order to be concealed under such a garment. When the French-line bikini (with a very high leg cut) was popular, the abdominoplasty incision had to be converted from a nearly horizontal line to an incision line that accompanied the inguinal fold. Since the turn of the century, bikinis with very low waistlines have become more popular again. Therefore, proper adjustments in techniques are again necessary to achieve a tailor-made abdominoplasty.

In 1977, Grazer and Goldwyn reported the first complications using new techniques. ^[9] Although aponeurotic suturing in the midline was noted to be able to reduce anterior projection of the abdominal wall, it did little to reduce the diameter of the waist.

In 1978, Psillakis first suggested suture plication of the external oblique musculature after raising it in a beltlike fashion. ^[10] In this way, he was able to dramatically reduce the diameter of the waist. He also added refinements such as costal margin excisions in patients with a projecting upper abdomen. With the addition of liposuction, Matarasso in 1988 expanded the use of abdominal contour surgery to a classification based on variations in patients’ anatomy, from liposuction alone to limited and full abdominoplastic surgery.

In 1995, Lockwood described the high lateral tension abdominoplasty. ^[11] Its key features include limited direct undermining, increased lateral skin resection with high tension wound closure along lateral limbs, and 2-layer superficial fascial system (SFS) repair.

The abdominal deformity is excess skin and subcutaneous tissue and laxity of the abdominal wall musculature.

Frequency

Abdominoplasty was the fourth most common aesthetic surgical procedure performed in the United States in 2019, with over 140,000 of the operations carried out that year, according to the Aesthetic Plastic Surgery National Databank. ^[12]

The most common cause of abdominal deformity is pregnancy, most often multiple pregnancies. Pregnancy stretches the skin beyond its biomechanical capability to spring back and stretches the musculoaponeurotic structures of the abdominal wall. The result is stretching and thinning of these structures and diastasis of the rectus muscle. Postpartum weight loss also contributes to the process. If skin retraction has not occurred in approximately 6 months, it probably will not occur. Massive weight loss, whether from dieting or after a gastric bypass surgery, also plays a role in excess skin and laxity of the abdominal wall.

The pathophysiology of the abdominal deformity is 2-fold. It includes (1) excess skin and subcutaneous tissue and (2) laxity of the abdominal wall musculature.

The most significant area of the defect is around and below the umbilicus, where excess skin over a diastasis of the rectus muscles is most apparent.

In 1972, Georgiade and Katras classified fat deposits on the trunk as lower medial or upper medial, based on the umbilicus. Patients are divided into 3 categories: (1) those with normal weight, (2) those who have mild-to-moderate obesity, and (3) those with massive weight loss.

As with all major surgical procedures, a complete history and physical examination are mandatory.

History

The medical history is extremely important. Previous pregnancies and their effects on the abdomen should be noted. Previous surgical procedures (including laparoscopic procedures) should be documented. The patient's history of weight gain and loss should be discussed. Finally, any future plans for pregnancy should be noted. A detailed inquiry into the patient’s history of medical problems should be performed. Severe heart disease, diabetes, and a history of thromboembolic disease should be noted. Less severe but also important information is the occurrence of wound problems, either from infection or connective tissue diseases.

Ensure that patients aren't smoking and are exercising before the surgery to promote overall well-being. Advise patients to be as close as possible to their desired weight before surgery. If patients are planning another pregnancy or planning to lose more than 10 lb, advise them to postpone the procedure.

Physical examination

The abdominoplasty is targeted at addressing abdominal deformities characterized by excess skin and subcutaneous tissue and laxity of the abdominal wall musculature.

Preoperative planning

The physical examination should be thorough. Concerning the abdomen, the location of all scars should be documented and the presence of abdominal hernias should be noted. Diastasis of the rectus muscles should be noted. The condition and strength of the abdominal wall should be evaluated. The amount, quality, and elasticity of the abdominal wall skin should be thoroughly evaluated.

Preoperative photographs should be taken and printed on 8.5 X 11-in paper. These can be used when discussing the procedure with the patient. Alternatively, an imaging system can be used.

Mass media influences drive what patients expect and desire from an abdominoplasty. Inflated patient expectations must be addressed.

Therefore, understanding the patient's aesthetic goals prior to the procedure is critical. For instance, the patient should understand that the excision of excess skin and fat does not flatten an abdominal wall distended from inside by a large omentum. In addition, multiparous patients with striae should not expect results exactly as they see in magazines. The patient should be as close to his or her ideal body weight as is practical prior to the surgery.

The location of scars should be marked directly on the patient’s skin or, at minimum, on the photographs. Candid discussions regarding the quality of these scars and potential wound problems should occur. Early wound problems include hematoma, seroma, marginal necrosis, and dehiscence. Late wound problems include hypertrophic scars, keloids, umbilical malpositions, and thromboembolic events.

Patients usually seek abdominoplasty for abdominal wall laxity, excess skin, striae, or diastasis of the rectus muscles. The ideal patient is within normal limits for his or her weight and height (ie, body mass index), has no plans for future pregnancies, has a moderate amount of excess of skin and fat, and has a mild diastasis of the rectus muscles. ^[13] Patients who seek body contouring following massive weight loss have their own set of criteria. They need to be evaluated regarding their candidacy for a belt lipectomy instead of abdominoplasty.

The abdominal wall is embryonically derived in a segmental manner, and this is reflected in blood supply and innervation. The transition of the embryo from a trilaminar disk to a 3-dimensional structure on the 22^nd day of gestation initiates formation of the abdominal wall. The development of the abdominal wall has multiple crucial stages; if the abdominal wall fails to undergo any stage in the sequence of events, congenital defects of the abdominal wall develop (ie, gastroschisis, omphalocele). The abdominal wall becomes a definitive structure after the umbilical cord is separated.

The musculature of the abdomen includes the paired rectus abdominis, which meet in the midline at the linea alba. These muscles originate at the infracostal margin, attach at the pubis, and are enclosed by a fascial sheath. In the upper two thirds of the rectus fascia, the anterior sheath is formed by the external and internal oblique aponeurosis, and the posterior sheath is formed by the internal oblique and transversalis aponeurosis. In the lower third, the posterior sheath is absent, and all 3 aponeurotic layers pass anterior to the rectus muscle, except the internal lamina of the transversus abdominis, the transversalis fascia, and the peritoneum, which pass posteriorly. This transition, known as the arcuate line, the linea semicircularis, or the semicircular line of Douglas, is present halfway between the umbilicus and pubic symphysis. At the caudal aspect of the rectus muscles, the pyramidalis muscles are present in 80-90% of patients.

The blood supply of the abdominal wall has been exhaustively described by Taylor and Palmer. ^[14] They introduced the concept of angiosomes, or vascular territories of the body. They describe 2 types of cutaneous blood supply: (1) direct vessels that directly supply the skin and (2) indirect vessels that "emerge from the deep fascia as terminal spent branches of arteries whose main purpose is to supply the muscles and other deep tissues." In a subsequent study in 1988, Moon and Taylor were able to demonstrate connections between the deep superior and deep inferior epigastric systems and their relationship to the cutaneous circulation. ^[15] The contributions of the superficial inferior epigastric vessels and the intercostal vessels were also delineated.

A clear understanding of the arterial supply of the abdominal wall is crucial to operative planning, especially when the patient’s history includes prior abdominal or chest wall surgeries. Huger’s description of the different zones of the blood supply guides the surgeon in planning and performing a safe operation. Huger defined zone I of the abdominal wall as the area that is fed anteriorly by the vertically oriented deep epigastric arcade. Zone III was described as the lateral aspect of the abdominal wall (flanks) that are fed by the 6 lateral intercostal and 4 lumbar arteries. The lower abdominal circulation is provided by the superficial epigastric, superficial external pudendal, and superficial circumflex iliac systems (zone II). A rich plexus between these systems allows collateral flow.

During abdominoplasty, the cutaneous blood supply to zone I and much of zone II is divided, with the abdominal flap circulation fully dependent on zone III. If a scar, such as a subcostal cholecystectomy incision, crosses the elevated flap, the circulation to the tissue distal to the scar is in jeopardy. A vertical midline incision can further jeopardize flap circulation.

The supporting structures of the abdominal wall have been elegantly described by Hartrampf. ^[16] He describes 2 static vertical supporting structures (linea alba, 2 linea semilunaris ligaments) and 2 static transverse ligaments (anterior rectus sheath, transverse tendinous inscription).

The superficial fascial system (SFS), the connective tissue network that resides below the dermis, has been implicated as a pivotal structure in body contouring procedures. Surgical repair of the SFS has been claimed to increase wound strength and decrease seroma formation. In a porcine model, Song et al showed that repair of the SFS layer in addition to dermis repair significantly increased the initial biomechanical strength of wound repair. This could lead to a decrease in early and late wound dehiscence, less widening of the scars, and lasting aesthetic results.

This in vivo model confirms Lockwood's idea that repair of the SFS results in a stable scar that heals without migration. This has the potential of changing or enhancing postbariatric body contouring outcomes, as the surgeon is dealing with large surface areas of tissue that need to be approximated under significant tension. According to the American Society of Plastic Surgeons statistics, approximately 68,000 body contouring procedures were performed in 2005 on patients who had experienced massive weight loss.

The nerve supply to the abdominal wall is via intercostal nerves VIII-XXII. These nerves pass between the internal oblique and transversus abdominis muscles. The motor branches pass behind the rectus muscles and enter the muscles at the junction of the lateral one third and medial two thirds. ^[15]

The skin of the infraumbilical and suprapubic areas of the abdomen is supplied by the iliohypogastric, ilioinguinal, and genitofemoral nerves. The skin of the abdomen is usually quite loose, except at certain points of adherence, ie, the anterior superior iliac crests and the linea alba. The subcutaneous tissue is divided by 2 layers of fascia, the superficial fascia (Camper) and the deep fascia (Scarpa), which is continuous with the fascia lata of the thigh. ^[17] With aging and pregnancy, fat tends to be distributed in the lower (infraumbilical) abdomen.

Striae are common, especially after multiple pregnancies. Striae are reported to be the result of rupture and separation of dermal collagen with resultant thinning. ^[18] Striae are not treatable except by excision.

The female body habitus follows a gynoid or hourglass shape. It is narrow at the waist and wider at the hips, with fat accumulation in the lower trunk, hips, thighs, and buttocks. Ideally, the female waist-to-hip ratio is approximately 0.7. The ideal male trunk contour has an android pattern, becoming narrower with descent from the chest to the hips in a V shape. Fat accumulation tends to occur circumferentially around the abdomen and flanks.

For more information about the relevant anatomy, see Regions and Planes of the Abdomen.

Contraindications to abdominoplasty include right, left, or bilateral upper quadrant scars (relative); severe comorbid conditions (eg, heart disease, diabetes, morbid obesity, cigarette smoking); future plans for pregnancy (relative); a history of thromboembolic disease (relative); morbid obesity (BMI >40); and unrealistic patient expectations.

The prevalence of obesity in health care settings is increasing to alarming levels. Plastic surgeons need to be aware of the comorbidities that are associated with obesity. In addition, only 5% of Americans are candidates for bariatric weight loss surgery. According to the American Society of Bariatric Surgery (ASBS), 200,000 patients will undergo massive weight loss surgery this year, and 75% of them will seek a plastic surgeon for body contouring after the weight loss surgery.

Current weight demographics in the United States include the following statistics: ^{[19, 20]}

• 66% of adults are overweight.

  • 31% are obese (categories I and II).

  • 5.1% are morbidly obese (category III).

• 32% of teens are overweight.

The most commonly accepted criterion for measuring obesity is the body mass index (BMI). This is defined by weight in kg divided by height in meters squared. The BMI categories are as follows:

• 20-25 healthy

• 26-29 overweight

• 30-34.9 obese (category I)

• 35-39.9 obese (category II)

• >40 morbidly obese (category III)

Additional relative contraindications include moderate obesity in a patient who expects a perfectly flat abdomen. Also, patients who tend to form keloids or hypertrophic scars should not undergo an abdominoplasty unless they are willing to accept the scarring associated with these conditions.