The surgical treatment of obesity originated with the concept that a surgical intervention to alter digestive anatomy and physiology could benefit patients with a metabolic related disease. At the University of Minnesota in the 1950s, surgeons performed an operation to bypass the distal small bowel to limit absorption of lipids in a patient with severe hyperlipidemia.¹ Over 60 years later, the field of metabolic and bariatric surgery has evolved to provide increasingly safe and effective surgical treatment options for patients who suffer the consequences of severe metabolic disease, such as type 2 diabetes mellitus. As these treatments have evolved, there has been a concurrent improved understanding of the physiology underlying the diseases being targeted. This has often been a result of the observations of treatment effects of surgical procedures. Increased insight and knowledge have also arisen as a result of trying to better understand how these interventions can be optimally used for disease treatment. The comorbid metabolic diseases that arise secondary to morbid obesity are generally much better understood than the actual disease of obesity itself. Consequently, surgical treatment has to date focused more on the improvements and resolution of those diseases rather than the disease of obesity. The major manifestation of the disease of obesity, weight itself, certainly has been the focus of bariatric surgery. However, the underlying genetic, physiologic, and metabolic factors that contribute to create the obesity disease state are still not well understood. Hence, surgical therapy has focused on weight as the parameter for treating the disease, while underlying causes are still not directly targeted. Indeed, as investigation continues as to the etiologies of the disease of obesity, surgical therapy may have a more limited role in the future. However, at this time it remains the single most effective treatment for reversing the disease, both in terms of the obvious problem of weight itself as well as the comorbid medical problems that accompany the disease in varying frequency from individual to individual.

The metamorphosis of the surgical patient who has had a successful bariatric operation and has changed from an individual literally burdened by diseases of—and related to—obesity is a dramatic and rewarding phenomenon. Metamorphosis is a truly accurate word to describe this therapeutic change. The massive improvement in quality of life, in physical, mental, and social areas, causes most patients who experience this process to be almost reborn in the true sense of the word. They are relieved of physical pain, social stigmatism, lifestyle limitations, low self-esteem, and a variety of other negative consequences of the obesity state with its concurrent problems. Often the simple fear of imminent death from obesity-related diseases, and the relief that treatment has allowed them to have a chance to live longer is a powerful aspect of treatment success.

The metamorphosis of the surgical patient who has undergone an operative procedure with successful weight loss and resolution or improvement of comorbid medical problems is joyful and dramatic. However, the patient who, after having achieved this success, then relapses into the obesity state through regain of weight and return of metabolic diseases, is equally tragic. To date surgery has been unsuccessful in optimally treating the latter patient, who represents perhaps 20% to 40% of patients who undergo surgical therapy for morbid obesity, depending on the procedure and nature of the diseases. Current surgical therapy is highly effective in treating the results of the disease of obesity: excess weight and the medical problems that result. This will be well illustrated in the text to follow. However, the reader is reminded that current surgical therapy is also not designed to eliminate the disease of obesity itself, a disease that is still poorly understood in terms of its etiology.

Bariatric surgery emanated from the need to control a severe metabolic problem. In 1954 in Minneapolis, Drs. Kremen and Linner performed the first jejuno-ileal bypass in a human to control hyperlipidemia. This case and a number of others were reported in the first series in the literature in 1963 by Payne.¹ The operation proved effective for treating that problem but caused a variety of malabsorptive and nutritional issues that proved to be unacceptable for all but the most severe cases of hyperlipidemia. Now, six decades later, the field of bariatric surgery is once more turning to the metabolic benefits of operative procedures as the main focus of further research and development of the field. Thus the appropriate appellation for the field is now metabolic and bariatric surgery.

Few bariatric operations were done in the 1960s. When Mason and Ito first described the gastric bypass in 1969, the first and longest-lasting bariatric procedure was launched.² After modification by Griffen to drain the gastric pouch using a Roux limb³ (Fig. 37-1), the procedure became alternatively the most or second most popular metabolic and bariatric operation from then until now. The history of bariatric surgery is one largely of those operations that have come and gone during the past five decades, while the Roux-en-Y gastric bypass (RYGB) has remained in use and provided effective results.

In the 1970s, the jejunoileal bypass was initially popular, then abandoned due to its occasional production of progressive and lethal hepatic failure.⁴ The damage to the reputation of the field of bariatric surgery from the backlash to the poor results of the jejunoileal bypass was felt for the next 25 years. Restrictive-only operations were thereafter viewed as much safer and more appropriate. While the gastric bypass did have a mild element of malabsorption, it was primarily a restrictive operation. Stomach stapling of various configurations was next performed, with all of them proving ineffective at maintaining adequate restriction for the long term if simple staple lines with gaps or gastric to gastric anastomoses were employed. In the 1980s, the vertical banded gastroplasty (VBG) (Fig. 37-2) was introduced, also by Mason, for the purposes of providing an operation with a durable anatomic configuration that was solely restrictive.⁵ The operation had a decade of success before it became apparent that patient adaptation to the restriction, which was to adopt a new diet of high-calorie liquids, usually defeated the operation in the long term.⁶ Stenosis of the outflow caused further need to revise the operation, to the point where most have now probably been converted to gastric bypass or other procedures.

Bariatric surgeons began to perform primarily malabsorptive operations in relatively small numbers once the initial success by Scopinaro and colleagues was demonstrated for the biliopancreatic diversion (BPD)⁷ (Fig. 37-3). Later, to avoid the high rate of marginal ulcer seen after BPD, both Marceau and Hess performed the duodenal switch (DS) (Fig. 37-4), which modified the gastric portion of the operation and used a duodenoileal anastomosis.^8,9

The advent of performing bariatric surgery laparoscopically evolved in the decade from 1994 to 2004, during which time Wittgrove’s initial success¹⁰ doing a laparoscopic gastric bypass was reproduced by others including Schauer¹¹ and Nguyen.¹² Gastric bypass was the procedure of choice at the time, and the one that U.S. surgeons learned to do initially laparoscopically. In 2003, the FDA approved the use of the laparoscopic adjustable gastric band (AGB) (Fig. 37-5), which had risen rapidly in popularity in Europe and Australia since its first performance by Belachew in 1993.¹³ The lap band was technically easy for surgeons to place, and it enjoyed considerable popularity in the United States for the next 5 to 6 years However, by that time it became clear the long-term results of the band were not what had been expected, and many patients began demanding to have them removed and revised to other procedures. By 2015, the lap band represented only about 5% of bariatric procedures performed in the United States, and for 2014 the published figure is 7.4%.¹⁴

Concurrent with the fall of the lap band was the rise of the sleeve gastrectomy (SG) (Fig. 37-6). It was originally performed as the gastric portion of the DS operation. When the DS was performed laparoscopically, the initial experience by Gagner showed a higher than expected morbidity and mortality.¹⁵ The operation was then divided into two stages, with the laparoscopic gastric portion of the operation being initially done, after which, with weight loss, the malabsorptive portion of the operation was added. However, many patients had such good success after just the gastric portion, they would not agree to any further surgery.¹⁶ Their success then stimulated surgeons to perform the SG as a primary procedure. It has now become the most popular procedure done both in the United States and internationally.

The history of bariatric surgery has been intertwined with the history of metabolic surgery. The two have now become relatively synonymous, but it has only been in the past 15 years that there has been significant attention devoted to studying the metabolic effects of bariatric operations. Pories and others had reported the astonishingly fast reversal of type 2 diabetes after gastric bypass many years earlier,¹⁷ but few others had focused on the changes that the operation caused in glucose metabolism until this century. Mechanisms of alterations of glucose metabolism, changes in systemic cytokine production, the variances and effects of the gut flora on metabolism, influences of circulating gastrointestinal hormones and other vasoactive peptides, and the role of neural input to satiety, food intake, and absorption have all been and are being studied currently, yielding a growing body of scientific knowledge to explain the clinical efficacy previously seen but not fully understood that is produced by bariatric operations. Adding to such knowledge in the future can only serve to improve the effectiveness of combatting obesity and its associated significant metabolic and systemic illnesses that serve as the leading cause for the now observed reversal of life expectancy from progressively longer to stable or possibly shorter for the next generation.¹⁸

The disease of obesity is complex, multifactorial, and cannot be adequately addressed in full detail in this chapter. However, there do seem to be some essential components that are important to the abnormal gain of weight by individuals who suffer from severe obesity. These include

1. 
   

   An occasional or steady alteration in satiety such that large quantities of food may be ingested in a single sitting

   
   
2. 
   

   Some genetic component to the disease, as yet still not well understood

   
   
3. 
   

   A likely environmental component to the disease, based on eating habits, lifestyle, and activity and exercise levels of individuals

   
   
4. 
   

   New evidence that gut flora may be important in influencing amounts of food absorbed between normal-weight and obese individuals

Obesity is currently classified into several categories. Table 37-1 gives the current Western definition of the classes of obesity, based on body mass index (BMI) (weight in kg/height in meters squared). Asian countries employ a slightly different classification, with class 1 obesity beginning with a BMI of 27. Severe obesity is associated with numerous comorbid medical problems. They are listed in Table 37-2. The major medical reason for performing metabolic and bariatric surgery is to improve these medical problems. While they are quite clear-cut, and the improvements of them have been well documented in the literature, they are not always the major reason for having surgery from the patient’s point of view. Often the patients are quite concerned with these problems, but they also may suffer from other less medically significant but just as altering lifestyle problems including ability to ambulate without difficulty, ability to bend and reach objects, to dress easily, to buy clothes off the rack, to be able to comfortably fit into seats for air travel, to drive a car comfortably, and to be able to play and interact with children and grandchildren. Loss of positive self-feelings, loss of sexual function and ability, and limited physical abilities to perform activities of daily living or activities required by a job all may play major roles in the patient seeking surgical help for the problem of severe obesity. Resolution of these issues is less well recorded in the literature, but well reflected in the very high patient satisfaction ratings for the results of their metabolic and bariatric operations, even when those operations do not meet the “standard” definitions of success we as surgeons have defined, such as loss of over 50% of excess weight and improvement in medical problems.

Psychosocial issues may also be very prevalent in the background of some patients who develop severe obesity. There is a known higher incidence of being physically, emotionally, or sexually abused as a child.¹⁹ The use of food as a means to combat anxiety, depression, or other adverse emotions may certainly complicate the disease process. Addressing such problems as a comprehensive treatment plan is important for optimal success for many patients. Addictive behavior to a pathologic extent is often felt to be a contraindication to surgery, and addressing such issues preoperatively to determine if the addictive behavior is severe enough to warrant disqualification from surgery is also very important.²⁰

The patient who seeks help surgically to combat weight problems and has not tried conservative therapy of dieting, exercise, behavior modification, or other such programs is a true rarity. It is safe to say that virtually all if not all of patients who undergo surgical therapy have tried to diet on their own or under medically supervised plans. Short-term success of loss of 5% to 10% of body weight is not uncommon for such patients, but regain of weight is almost universal and progressive weight gain with advancing age, further pregnancies, or other life crises is the usual history given by patients. The percentage of patients who are successful in losing more than 10% of body weight through diet and exercise programs and keeping it off for years is estimated to be in the 3% range.

Selection of patients then, for surgery, is based on the criteria given in Table 37-3. These criteria were established at the time of the last National Institutes of Health (NIH) Consensus conference on surgical treatment of obesity. Most experts agree that the criteria are outdated and need revision. In particular, there is now good evidence in the literature that for stage 1 obesity, surgical intervention can have significant benefits for the treatment of associated medical problems, particularly type 2 diabetes.^21,22

The actual criteria from that NIH conference also included the need to follow patients long-term. While all attempts to do so have been exercised by many practices, including our own, a very high follow-up rate is difficult to achieve long-term due to a variety of problems, including but not limited to loss of insurance coverage for follow-up visits, geographic relocation, and simple lack of motivation to take a day off work to be seen when one is doing well and follow-up is already well established with the primary care physician. We recently were able to document the fact that our approximately 20% to 25% follow-up rate for patients based on voluntary return to clinic annually was an excellent representative sample of the outcomes of the whole group. When the group of patients who had been seen in follow-up regularly for over ten years after gastric bypass was compared to those patients who had not been seen recently but were re-contacted through a special study, there was no difference in the outcomes for the group that had been followed closely versus the one that had been lost to follow-up.²³ We feel these data debunk the popular criticism raised in the past of many publications reporting results after metabolic and bariatric surgery which did not have a high follow-up percentage of patients. It is likely the patient sample being seen is representative of the group, based on our experience.

Controversial criteria for inclusion of patients for metabolic and bariatric surgery include age, weight (upper limits), and sometimes individual surgeon requirements for adherence to preoperative diets and cessation of any addictive habits. Relative to age, the younger range of patients can be variable. Large series of adolescent patients have been reported after undergoing metabolic and bariatric surgery, with good success.²⁴ Most bariatric surgeons who are not pediatric surgeons, however, do not include many patients under the age of 18 in their practice, but there is no hard and fast rule on this. Similarly, some bariatric surgeons have an upper age limit for performing various operations. Others assess patients on an individual basis for likelihood of being able to physiologically tolerate and recover well from surgery. While many series of older patients have been reported with successful outcomes in the literature, careful scrutiny of larger collected databases reveals the invariable increased incidence of postoperative mortality and slight increases in morbidity for the population over age 65.²⁵

Some surgeons impose a mandatory preoperative diet to achieve a small amount of weight loss for their patients. A few have published a demonstrated benefit for doing so, largely to eliminate the potential for a fatty liver and its technical interference with surgery.²⁶ However, insurance companies have almost uniformly now adopted a policy of requiring patients to complete a medically supervised diet. This can be as long as 12 months. The benefit of such preoperative diets has clearly been shown to be negative in the literature, and such onerous requirements often serve only to delay the ability of patients in need of the benefits of surgical therapy to receive them. The American Society for Metabolic and Bariatric Surgery (ASMBS) has recently published a review of this topic with strong recommendations against this practice.²⁷

Many practices and institutions have upper limits of weight at which they will no longer offer metabolic and bariatric surgery. We also have such a limit, though it is high (600 lbs). At very high weights, the ability to safely perform surgery and to diagnose and treat potential postoperative problems becomes prohibitive if the size of the patient precludes postoperative imaging studies, safe transfer and ambulation, and adequate facilities to meet the patient’s needs.

Most centers that now perform bariatric surgery participate in the Centers of Excellence program under the supervision of the American College of Surgeons (ACS) working together with the ASMBS. The merger of the two systems of accreditation for bariatric surgery centers happened about 6 years ago, and the current Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) certifies most medical centers in the country that perform metabolic and bariatric surgery. This centers of excellence concept has been instrumental in improving the overall quality of surgical care rendered to patients undergoing metabolic surgery. Standards for professional training, surgical outcomes, patient education and follow-up, use of a multidiscipline team approach, equipment and supplies in both the inpatient and outpatient settings, and reporting of data all are important components to the accreditation formula, which has produced demonstrably better outcomes in centers of excellence versus centers that have not been a part of such a system.²⁸

The benefit of a multidiscipline team in rendering the best possible care for patients is generally espoused by those with experience in the field. The MBSAQIP recognizes the need for such an approach. Table 37-4 gives a list of the essential and the desirable professionals that are best incorporated into the multidiscipline approach to metabolic and bariatric surgery.

Once a patient has decided they wish to undergo metabolic and bariatric surgery, the single biggest hurdle they face in the United States today is obtaining insurance approval for this procedure. Despite many articles in the literature documenting the long-term financial savings in health care costs for patients who undergo metabolic surgery versus those who do not,^29-31 the current climate of insurance support for these procedures is one of near hostility. Other than an innate bias against obesity and the concern that a loosening of criteria would bring a wave of patients to receive the benefits of appropriate surgery, there seem no other logical explanations other than the fact that the average duration of an insurance policy may only be about as long as the time it takes for the benefits of surgery to be seen long-term in terms of financial savings. Thus if an insurance company is concerned only about that quarter or yearly expenses, they could conceivably take a position that the short-term cost savings are not adequate to support metabolic surgery. However, if all the insurance industry were to adopt the policy of supporting these procedures, then the well-documented savings in costs to patients over a 3-year or longer period would be realized. In the state of Virginia, for example, there is actually a law that states any insurance company that offers comprehensive health insurance must offer treatment for severe obesity, including a surgical option. What the insurance companies have done, however, is make such coverage contingent upon a special rider to the policy that charges an exorbitant amount (for example, $5000 extra per patient per year) for this coverage. Small employers cannot afford these major increases in premiums. Small employers in Virginia have also recently been denied the ability to obtain bariatric coverage for any price if their number of employees is very low. Thus the only patients who are currently able to obtain insurance approval in Virginia at this time are largely employed by the state, large corporations, or have federal insurance (Medicare and Medicaid). These riders have effectively eliminated access to health care for many deserving patients in the state of Virginia. The story is repeated in many versions across the country. Obesity remains the last unlegislated bias in our society.

If a patient is fortunate enough to potentially receive insurance approval for metabolic and bariatric surgery, the other issues that need to be decided early on are:

1. 
   

   Appropriateness for surgery as judged by the multidiscipline team

   
   
2. 
   

   The most appropriate procedure for the patient and agreeable to her/him

   
   
3. 
   

   Identifying and optimally preoperatively treating associated comorbid medical problems

Sufficient preoperative visits to determine the answers to all three of the above issues are needed. For our practice, our initial visit encompasses multidiscipline evaluation, extensive teaching, and identification of medical problems. The most appropriate operation is also chosen. A period of time in which insurance company requirements are then fulfilled, insurance approval is obtained, and medical issues are optimally treated then follows. Finally, another clinic visit in which review of the operative procedure, reinforcement of perioperative expected outcomes, review of expected measures to speed safe surgery and recovery, and the early phases of postoperative diet and exercise plans are again reviewed. The operative consent is discussed in great detail. A date for surgery is chosen.

Choice of Operation

Patient preference does play a role in choice of operation. If a patient simply will not undergo an operation, that is the end of that discussion. I would prefer to offer a patient some surgical therapy that will treat his or her severe obesity and its medical problems to a great extent, even if it is not the most optimal operation for a patient, than perform nothing. A few exceptions exist of course to this general statement. Some guidelines we use in helping to select operative procedures are as follows:

1. 
   

   RYGB results in better treatment of preoperative gastroesophageal reflux disease (GERD) and severe, especially insulin-dependent type 2 diabetes.

   
   
2. 
   

   Patients who are smoking are not candidates for RYGB (complications of marginal ulcers).

   
   
3. 
   

   The laparoscopic AGB has a very limited applicability for likely success.

   
   
4. 
   

   Patients with extensive bowel surgery are likely best served with an SG.

Currently, SG has replaced gastric bypass as the most commonly performed procedure in the United States and in the world (Table 37-5) This popularity is likely due to its efficacy to date, and the fact it is a technically easier procedure for the average laparoscopic surgeon to perform. Patients are also demanding it because of the often-verbalized perception that it is “less invasive.” While it does avoid any change in the route of the alimentary tract, sending 70% of the stomach to the pathologist is not exactly less invasive. It does also have the benefit of having less long-term complications, especially avoiding the problems of bowel obstruction and marginal ulcers seen after gastric bypass. For many patients, the SG is very appropriate. We tend to recommend gastric bypass for patients with significant GERD, significant type 2 diabetes, and who have a BMI over 60. Some surgeons would argue the patient with a BMI over 60 should undergo a malabsorptive operation, and that is valid based on the outcomes data.³² However, I have chosen not to perform malabsorptive procedures since our patient population often comes from a long distance and keeping close follow-up is very difficult. Close follow-up is uniformly felt to be a requirement for performing malabsorptive procedures such as the duodenal switch.

Evaluating Medical Problems

Once the operation has been chosen, the patient must be evaluated and treated for associated comorbid medical problems. The medical problems most often not identified prior to our evaluation have included obstructive sleep apnea, hyperlipidemia, and gallstones. However, the entire list of problems given in Table 37-2 should be assessed for existence, and tested for if they may be present. Appropriate preoperative treatment is indicated. Baseline metabolic deficiencies that are common in the patient population considering metabolic surgery include iron deficiency anemia, vitamin D deficiency, and hyperglycemia from unrecognized early diabetes. Common preoperative screening tests we employ include an upper endoscopy for anyone with symptoms of GERD. Detection of Barrett esophagus, though infrequent, is essential preoperatively. The incidence of lesions that may alter the surgical treatment to some extent has been approximately 5% based on our historical data.³³ A sleep study is ordered for patients with high assessment scores for sleep apnea. An ultrasound of the gallbladder is routinely performed for all patients with a gallbladder. Other pertinent positives in the history and physical include risk factors for increased incidence of venous thromboembolism (VTE), including previous history of VTE, pulmonary hypertension, and venous stasis ulcers.

During this evaluation, conditions that might merit simultaneous second surgical procedures may be identified. The two most common are gallstones and abdominal wall hernias. We have recommended that patients who have gallstones undergo a simultaneous laparoscopic cholecystectomy. Our results in performing this procedure associated with gastric bypass have been published and show an extremely low (less than 1%) incidence of complications from the cholecystectomy as well as no increased length of stay or morbidity.³⁴ For patients who do not have gallstones, we advocate a 6-month course of ursodiol at 300 mg bid to decrease the incidence of postoperative gallstones to approximately 4% (data obtained after gastric bypass).³⁵

Abdominal wall hernias are not infrequent in this patient population. The most common primary one is umbilical hernia. If an umbilical hernia is large enough to potentially have a loop of bowel incarcerate in it postoperatively, it should be repaired. Studies carried out on the question of whether to repair abdominal wall hernia defects at the time of gastric bypass or defer repair until later have shown a significantly high incidence of incarcerated hernias needing emergency surgery when the hernia was not repaired at the time of the gastric bypass.³⁶ Now, even the use of mesh to repair abdominal wall defects after SG has been shown to be safe, based on negative intraoperative peritoneal fluid cultures during one study.³⁷ For the extremely large hernia where there is significant bowel involvement in the hernia sac, performance of an open procedure to repair the hernia and do the metabolic operation simultaneously seems the best choice. In this patient population, the incidence of postoperative infections is less well documented, so primary repair and closure if possible is still recommended until further data are available.

The most commonly unplanned procedure performed during metabolic and bariatric surgery is a liver biopsy. Some institutions perform them routinely or nearly routinely, so that the procedure is not unplanned. However, most practices, ours included, will perform a laparoscopic liver biopsy based on the gross appearance of the liver. Any excessive fattiness, and certainly any evidence of scarring are indications for a biopsy. Biopsy results showing any degree of fibrosis should have follow-up with a hepatologist.

Patient Education

The major components of preoperative preparation are optimal treatment of medical problems, patient education, and adherence to planned preoperative protocols as indicated. We have discussed the treatment of existing medical problems above. The importance of preoperative education and teaching is paramount. Patients who are educated and know what to expect will be much more at ease with the events before and after surgery. They will be prepared to follow instructions and recommendations more closely, with better outcomes. Realistic expectations of time in the hospital, pain and its treatment, expected recovery time, and other postoperative issues should all be well discussed before surgery.

Preoperative Protocols/ERAS

Preoperative protocols differ from institution to institution. Many institutions now have adopted the early recovery after surgery (ERAS) type guidelines for many procedures, including metabolic surgery.³⁸ The truth is, metabolic surgery, by doing virtually all procedures laparoscopically, emphasizing early ambulation as a prophylaxis against VTE, and avoiding nasogastric tubes and introducing liquids soon after surgery, had already achieved many of the main components of the ERAS protocol. Improvements in pain control and volumes of intravenous fluids given during surgery by our anesthesiology colleagues have been definite benefits of an ERAS program. The ability of patients to take liquids until 2 hours prior to surgery has also been a benefit for our patients, who otherwise were often a bit dehydrated at the start of surgery since their daily liquid requirement is increased due to increased body habitus.

Other than ERAS protocols, some practices have incorporated preoperative diets of the short-term low-carbohydrate variety for their patients. We have not used this approach, and have had few reasons to consider doing it. Enforcement and the penalties for noncompliance seem to be more difficult issues for us than the benefits. Such benefits of a preoperative diet have been reported by some surgeons in surgeon-supervised diets, but the overall improvements in outcomes have been modest and not enough to recommend that this practice be uniformly adopted.²⁷

VTE prophylaxis is important, yet there is no one agreed-upon formula. Based on the clinical practices of members of the ASMBS,³⁹ most patients receive sequential compression foot or leg devices to wear during surgery and while hospitalized postoperatively. Most patients also receive chemoprophylaxis using either regular or low molecular weight heparin. Most surgeons begin this just prior to surgery, with subcutaneous prophylactic doses based on weight. The duration of chemoprophylaxis is controversial. High-risk patients should get a longer course, but whether that is 1 week or up to 4 weeks or longer is still unclear. Despite the importance of this topic, and the fact that pulmonary embolism remains the leading cause of death after metabolic and bariatric surgery, there is still not widespread agreement on the type of heparin, its timing and duration that is optimal for prophylaxis.³⁹

Preoperative antibiotics given intravenously within 1 hour prior to starting surgery and redosed until the procedure is completed (and in some institutions up to 24 hours later) has been proven effective in decreasing surgical skin site infections.

Postoperative Protocols and Follow-Up

Postoperative protocols have evolved over the years to now embrace relatively early discharge from the hospital. Sleeve gastrectomy patients being discharged on the first day after surgery, and gastric bypass patients being discharged either then or the second day after surgery are well published and accepted as safe practice. Early ambulation, early feeding, and minimizing opioid narcotic use with substitution of other non-narcotic pain medications are now hallmarks of most postoperative protocols after metabolic surgery.

Long-term postoperative follow-up has always been advocated to determine the outcomes of the intervention of metabolic and bariatric operations. As noted above, we now have evidence that a substantial sampling, without complete follow-up, of patients probably gives an excellent approximation of the true outcomes of long-term results. Metabolic side effects and consequences exist for all the operations, though the malabsorptive procedures have much greater potential metabolic derangements long-term.

Nutritional Issues Following Surgery

Completely restrictive operations that do not alter the alimentary tract, such as the laparoscopic AGB, have the only consequence of decreasing total nutrient intake. A multivitamin is all that is recommended for postoperative prophylaxis. For the SG, where the stomach is decreased in volume, adding a reliably absorbed source of vitamin B₁₂ is indicated due to the role of the stomach in its normal absorption. Patients who undergo gastric bypass are at risk for malabsorption of iron and calcium, both preferentially absorbed in the duodenum and proximal jejunum. Diversion of the stomach from the food stream also decreases B₁₂ absorption. Supplements for these two minerals and vitamin B₁₂ are indicated as well as a multivitamin to protect against low folate levels or other vitamins not as well absorbed after gastric bypass. Malabsorptive operations, such as the duodenal switch, can produce protein calorie malnutrition as the most severe consequence. Parenteral nutrition may be needed to correct malnutrition, and the reoperative rate to address long term consequences is approximately 7%.⁴⁰ Periodic replacement of fat-soluble vitamins via a parenteral route in addition to all the supplements recommended for gastric bypass is standard for patients after a duodenal switch. For all patients who have metabolic surgery, annual or more frequent follow-up by a physician (primary care or surgeon) is indicated long-term to help monitor and prevent any of the above vitamin and mineral deficiencies.

In 2017, there are now two main operative procedures done as metabolic and bariatric operations: SG and RYGB. There are two procedures uncommonly done: laparoscopic AGB and DS. There is also an emerging, not yet considered standard procedure gaining popularity that may well become a standard procedure in the near future: single anastomosis gastric bypass (SAGB). Finally, there are nonsurgical weight loss options now available for patients with class 1 obesity such as intragastric balloons, endoscopic sleeve gastroplasty, and others, which are described below as well. Operative procedures that have only historic interest, such as vertical banded gastroplasty or biliopancreatic diversion are not described, as they are now rarely performed. A special section on revisional operations is also included. In addition, no longer is any extensive description given to open operative procedures, as they have now all been well eclipsed by their laparoscopic counterparts and have relevance only in a historic sense or in operative procedures where previous surgical scarring (such as in revisional surgery) make an open approach necessary. In general, few variations from the laparoscopic approach in terms of the operative steps are needed when converting from laparoscopic to open surgery. Thus all operative descriptions to follow assume a laparoscopic approach is used. The operative descriptions below are how I perform these operations. Most can have significant variability in the steps and techniques and still accomplish the same operation, and this is certainly acknowledged.

Sleeve Gastrectomy

TECHNIQUE

Port placement involves a 12-mm camera port approximately 15 cm down from the xyphoid and just to the left of the midline, two ports for the surgeon in the right upper quadrant, with the lower of the two being a 15-mm port and the upper a 5 mm port. The operation is best conducted if the skilled first assistant has two 5-mm ports in the left upper quadrant for assisting. (Fig. 37-7). We also favor always using a 10-mm 45-degree telescope for our procedures.

The liver is retracted with a Nathanson retractor, placed in the left xyphoid region to retract the left lobe of the liver. The pylorus is identified. The harmonic scalpel is used to divide the attachments to the greater curvature of the stomach beginning 4 cm proximal to the pylorus and ending at the left crus of the diaphragm (Fig. 37-8). Care must be taken to avoid splenic injury in dividing the short gastric vessels. Any posterior gastric adhesions should also be divided so that the stomach is mobilized on the lesser curvature blood supply and the prepyloric vessels.

The sleeve is now created. Using an intragastric dilator or tube is helpful to gauge sleeve luminal size. It has been shown that a 40 Fr dilator is optimal size for the lumen. Anything smaller must not be directly touching the stapler as it is closed, or too narrow a lumen may result. The area where narrowing is most common and is most concerning is the incisura. Staple height is gauged by stomach thickness, with higher staple height loads being used on the antrum and shorter ones on the fundus. Controversy exists as to whether to use buttress material while stapling. Large pooled data show a slight difference in favor of less bleeding if such buttressing is used, but the differences are not appreciable in common practice. Leaks are no different whether buttressing is used or not. Some surgeons reinforce their staple lines with oversewing, and some suture only areas of obvious bleeding or concern.

I personally use an Ewald tube (34 Fr) and place the stapler close but not directly adjacent to it while it is positioned along the lesser curvature (Fig. 37-9). Once the sleeve is created, the tube serves as a good mechanism for injecting methylene blue dye forcefully into the stomach to confirm security of the staple line. The resected stomach is removed through the 15-mm port site, enlarging it slightly as needed. We close all port sites 10 mm or larger with interrupted suture or sutures of 0 Vicryl placed laparoscopically with a Berci suture passer.

OUTCOMES

SG has been shown to produce an excess weight loss at 8 years of 67% in one series.⁴¹ It improves medical conditions quite well, as shown in data from the ACS Bariatric Surgery Center Network (BSCN) initial report on the first 900 plus such procedures recorded in that database⁴² (Table 37-6). The one medical problem that is not well treated by SG is GERD. Patients who have GERD have been shown to do less well on the whole than those who do not. GERD is reported as variably improved after SG. In the ACS database, it was improved in 50% of patients versus 70% after RYGB.⁴² In other series GERD was reported to arise anew in from 8% to 47% of patients previously asymptomatic after SG.^43,44 Preoperative and intraoperative search for the presence of a sliding hiatal hernia, and its subsequent repair at the time of SG can improve these results. Barrett esophagus is considered a contraindication for SG by many surgeons.