Post-bariatric reconstruction

Definition and epidemiology

Overweight and obesity refer to ranges of weight that are greater than that considered healthy for a given height. The primary measurement for obesity used to categorize patients is the body mass index (BMI). According to the World Health Organization, overweight is defined as a BMI between 25 and 29.99 kg/m ² . Obesity begins at 30 kg/m ² with obese class I equivalent to 30–34.99 kg/m ² . Modifications to the classification have been added, including the categories of super obese (50–60 kg/m ² ), and super, super obese (>60 kg/m ² ) ( Table 38.1 ).

In the US, obesity is increasing at an alarming rate. The US obesity prevalence was 41.9% from 2017 to March 2020. Approximately 9.2% are severely obese. Worldwide, according to the World Health Organization, 39% of adults aged 18 years and over were overweight in 2016, and 13% were obese.

Obesity is an independent risk factor not only for all-cause mortality but also for major diseases including coronary heart disease, type 2 diabetes, hypertension, certain malignancies, and musculoskeletal disorders. One cannot ignore the psychosocial ramifications of obesity. Disturbingly, obesity is predicted to overtake smoking as the leading cause of death in the US. Not only does obesity result in lower societal productivity and higher healthcare costs but also rises in patient morbidity and mortality have spurred governmental interventions.

The etiology of obesity is more complex than originally thought. Although some simplify the problem to “more calories in than out”, other factors, including genetics, environment, and psychological factors are influential. Notoriously difficult to treat, obesity is often resistant to many forms of therapy. Gastric bypass procedures have been shown to provide cost-effective, durable long-term weight control in the moderately to morbidly obese, and weight loss procedures have been evolving as guided by. The growing number of bariatric surgical procedures performed has resulted in a higher demand from patients seeking removal of the excess skin and fat that remains following weight loss.

MWL from surgery or diet and exercise alone may be described as weight loss in excess of 50 lb, although weight reduction of more than 100 lb is quite common. Plastic surgeons have pioneered techniques for this population by modifying traditional surgical approaches and techniques in order to appropriately treat the unique deformities found in this emerging patient population.

Diet and exercise

Diet and exercise play an integral role in any weight loss regimen. Simplified, in order to lose weight, caloric intake must be less than total body expenditure of energy in order to consume endogenous triglycerides. Caloric restriction may take the form of generalized reduction in calories, but may be aided by adjustments in the types of macronutrients eaten (e.g., fats, carbohydrates). A recommended diet of between 1000 and 1200 kcal/day for women, and 1200–1600 kcal/day for men is commonly followed for a target weight loss of 1–2 lb per week. In most cases, an initial weight loss of 10% of body weight over a 6-month period is suggested. Unfortunately, long-term studies have found diet therapy alone is ineffective in the treatment of obesity.

Often coupled with a reduction in caloric intake is physical activity or an exercise regimen. Physical activity is valuable, primarily aiding in long-term weight loss maintenance. Isolated physical activity with no changes in a high-calorie diet is insufficient to cause significant amounts of weight loss.

Pharmacotherapy

The anorectic agents fenfluramine and phentermine have both, in the past, been approved by the Food and Drug Administration (FDA) as individual agents. However, these drugs are not commonly used to treat obesity due to associations with the development of primary pulmonary hypertension and valvular heart disease.

Currently, weight loss drugs are approved by the FDA for patients who have a BMI ≥30 kg/m ² , or a BMI between 27 and 29.9 kg/m ² in conjunction with an obesity-related medical complication. The majority of weight loss medications are anorexiants. Most are only approved for short-term use, and patients typically regain weight once discontinued.

History

Patient evaluation includes a complete medical history. A distinction must be made in the mode of weight loss. Key information to obtain regarding the patient's weight includes:

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  Date and nature of bariatric surgical procedure

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  Maximum, lowest, and current weight and BMI

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  Goal weight

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  Recent (past 3 months) changes in weight status.

Other important history required includes:

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  Past or current tobacco use

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  Prior surgeries

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  Prior pregnancies, plans for future pregnancies

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  Breast history, including prior surgeries, history of cancer, family history, mammographic history, breast biopsies

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  Prior deep venous thrombosis/pulmonary embolism, or coagulopathy

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  Psychiatric history

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  General medical issues.

Many patients will have had numerous medical comorbidities prior to weight loss that have improved significantly or since resolved. These benefits commonly occur within 2–5 months following bariatric surgery. Sequelae of gastric bypass must also be assessed, including history of past or current dumping syndrome or prolonged emesis.

Screening for nutritional status is important. Protein intake by history is considered adequate if 70–100 g of protein per day is reported, although serum protein measurement is indicated before post-bariatric body contouring. Following bariatric surgery, protein is one of the major nutrients affected and may be reflected as hypoalbuminemia, anemia, and edema. Although seen in Roux-en-Y gastric bypass, the most common procedures associated with protein deficiencies are malabsorptive in nature, such as the biliopancreatic diversion. Protein intake is essential for wound healing, especially if multiple contouring procedures are performed. Pre-albumin and albumin levels elucidate issues with protein intake and absorption. Protein supplementation may be required preoperatively.

Deficiencies in nutrients and vitamins, such as thiamine, folate, B ₁₂ , and iron are common. A history of current or past supplementation may screen for this. Nutritional deficiencies are most common in malabsorptive procedures, including Roux-en-Y gastric bypass and biliopancreatic diversion.

Anemia is not uncommon in the MWL population and may be related to generalized or specific nutrient deficiencies. Although iron deficiency is most common, micronutrients such as B ₁₂ , folate, copper, fat-soluble vitamins A and E, or zinc may be deficient and contribute to anemia. A complete hematological workup, including measurement of iron stores, should be performed, especially in high-risk patients. In some cases, iron deficiencies may be refractory to oral therapies and require more aggressive treatment with parenteral iron, blood transfusions, or surgical interventions. Iron deficiency may be seen in association with any gastric bypass procedure.

Physical examination

A generalized physical assessment of the degree of skin excess, distribution of fat, number and location of rolls, and the quality and elasticity of the remaining skin indicates which areas of the body would benefit from contouring surgery. Characteristically, patients will present with predictable patterns of tissue descent around the body.

Zones of adherence, which are tight, non-yielding areas of fascial attachment to the underlying muscular system, act as tethering points from which skin laxity will hang. These areas of restriction are located in the midline of the anterior and posterior trunk and around the pelvic rim. Areas of skin and soft tissue that are farthest in distance from the zones of adherence descend the most following MWL, which in most patients includes the lateral truncal tissues. The estimated skin resections may be simulated by performing “pinch tests”, which may also help determine the translation of pull (distance from the pinched area that tissues are affected).

Scars from prior surgeries are important to document, as a reduction in blood supply may require technical modifications during surgery. Commonly, rectus diastasis may be discovered. Ventral hernias are reducible or non-reducible, and the edges of the hernia may be palpated. A breast examination should be performed, noting masses, position of the nipple–areola complex, and skin envelope quality. Asymmetries are pointed out to the patient. Lateral thoracic skin rolls are noted. Standardized photographs are taken.

Assessment

A proper medical workup is essential. Preoperative clearances from internists, psychiatrists, and other physicians that care for the patient are the rule. Investigations include a chest X-ray, electrocardiogram, complete blood count, coagulation profile, pre-albumin, albumin, pregnancy screen in females of child-bearing age, and mammogram if breast surgery is considered. Abdominal computed tomography in cases of suspected hernias will aid surgical planning.

Patient preoperative counseling and education

Preoperative counseling exploring the patient's goals, expectations, and areas of greatest concern aids in patient selection. Patients are questioned on areas of the body of greatest priority requiring correction, especially when multiple procedures are performed. Education regarding the areas of the body that may be contoured concurrently and discussion as to the appropriate staging of procedures are undertaken. Patients must be made aware of the lengthy scars that occur with large skin resections and must be willing to trade a better contour with the resultant scar.

Education must focus on pre- and postoperative expectations, the length of the surgical procedures, as well as the nature and length of recovery following multiple procedures. As the majority of surgeons use drains in the initial postoperative period, information regarding drain care should be given. Patients must have appropriate social support at home in order for a smooth recovery to occur. No lifting of items heavier than 10 lb is a good rule of thumb for patients undergoing abdominal procedures.

Abstinence from medications that predispose to bleeding, including herbal medications, is important. Tobacco use is a relative or absolute contraindication for body contouring by most surgeons. Smoking cessation helps to minimize flap loss and wound complications such as dehiscence and infection. Although there is no consensus, a commonly used guideline is abstinence from tobacco or nicotine replacement therapies for at least 4 weeks prior to and 4 weeks post-elective cosmetic or reconstructive procedures.

Informed consent is a key element of preoperative counseling. Patients must understand that body contouring after MWL may require multiple stages and possible revisionary surgeries. The surgeon's revision policy must be emphasized to patients and the difference between secondary procedures (further skin tightening) and revisions understood. In general, MWL patients experience mild to moderate amounts of skin relaxation postoperatively, resulting in the need for further skin resections. There is also the possibility of contour irregularities and postoperative “dog-ears” at the extents of resection. A comprehensive guide to informed consent in body contouring patients following MWL is available from the American Society of Plastic Surgeons.