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September/October 2009

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Surgical Management of Severe Obesity: Currently Used Approaches
Weight loss surgery seeks to reduce the morbidity and mortality associated with obesity and to improve metabolic and organ function.
Reviewed By Edward C Mun, MD, FACS

As has been much discussed, the prevalence of obesity—defined as a body mass index (BMI) >30 kg/m²—is skyrocketing worldwide. According to a literature review by Edward C. Mun, MD, FACS, and Ali Tavakkolizadeh, MD, published online at www.UpToDate.com, between 1991 and 1998 the percentage of obese men nearly doubled, and the percentage of obese women increased by 50%.1 More than 33% of adults in the United States are obese,2,3 and more than 64% of Americans are overweight (BMI ≥25 kg/m²).

Serious health risks associated with obesity include type 2 diabetes, heart disease, stroke, certain cancers, osteoarthritis, liver disease, obstructive sleep apnea (OSA), and depression. Behavioral, medical, and surgical options have been used for successful weight loss. Dr. Mun, Assistant Professor of Surgery, Harvard Medical School, and a member of the American Society for Metabolic and Bariatric Surgery, and Dr. Tavakkolizadeh, Associate Surgeon at Brigham and Women's Hospital, undertook this review of available surgical procedures.

EFFECTIVENESS OF BARIATRIC SURGERY
Individuals undergo weight loss surgery to reduce the morbidity and mortality associated with obesity and to improve metabolic and organ function. Numerous studies have stated that such surgery is effective in reducing comorbidities, and it may have additional benefits such as reducing societal costs in caring for patients and improving their quality of life.4-16 There are, however, perioperative complications and mortality.17-18

Drs. Mun and Tavakkolizadeh reported that a 136-study meta-analysis found:

  • A mean percentage of excess weight loss of 61% (excess weight loss refers to the difference between the preoperative BMI and a BMI of 20 to 30 kg/m² depending on the study).
  • A 30-day mortality rate of 0.1% for restrictive procedures, 0.5% for gastric bypass, and 1.1% for biliopancreatic diversion or duodenal switch.
  • Diabetes resolved in 77% and resolved or improved in 86%, hyperlipidemia improved in about 70%, hypertension resolved in 62% and resolved or improved in 79%, and OSA resolved in 86% and resolved or improved in 84%.

A slightly larger meta-analysis from Maggard et al18 concluded that bariatric surgery was most beneficial among patients with a BMI of >40 kg/m². In this work, weight loss was greater with gastric bypass versus gastroplasty. Overall mortality was <1%, and adverse events occurred in about 20% of patients. Fewer wound-related complications were associated with laroscopic procedures versus open surgery.

The SOS (Swedish Obese Subjects Trial) compared surgical versus medical treatment of morbid obesity. SOS included 4,047 obese patients (BMI: men >34 kg/m², women >38 kg/m²). A total of 2,010 underwent surgery for obesity (gastric banding, gastroplasty or gastric bypass), and 2,037 chose conventional treatment. Several major observations have been reported. These include:15,19-27

  • Control patients' weight increased 0.1% versus with a 23% weight decrease for patients choosing surgery27 at the 2-year mark. At 10-year follow-up there was a 1.6% increase and a 16% decrease, respectively. Two- and 10-year rates of recovery were better for diabetes (odds ratio [OR], 8.42 and 3.45, respectively), hypertriglyceridemia (5.28 and 2.57, respectively), low levels of high-density lipoprotein cholesterol (5.28 and 2.35, respectively), hypertension (1.72 and 1.68, respectively), and hyperuricemia (5.36 and 2.37, respectively). Patients who underwent surgery had lower 2- and 10-year incidence rates of diabetes (OR, 0.14 and 0.25, respectively), hypertriglyceridemia (OR, 0.29 and 0.61, respectively), and hyperuricemia (OR, 0.22 and 0.49, respectively).
  • Medications for cardiovascular disease or diabetes medications were reduced in SOS patients who underwent surgery (risk ratio, 0.56 to 0.77).23
  • Patients who had surgery enjoyed major quality-of-life improvements according to validated instruments, compared with medically treated patients at 2 years.19 Weight gain at the 10-year follow-up diminished some of the quality-of-life improvements.

A randomized trial found laparoscopic adjustable gastric banding to be significantly more effective than medical management at 2 years among mildly to moderately obese (BMI 30 to 35 kg/m²) patients, according to work by O'Brien and colleagues and Perry et al.29,30

Type 2 diabetes. Drs. Mun and Tavakkolizadeh reported that a randomized trial of 60 patients by Dixon et al, showed that diabetes remission occurred more often in surgically treated patients (73% vs 13%)31 compared with lifestyle modifcation and medical therapy. How diabetes improves in these patients is related to the type of weight loss surgery,32 Drs. Mun and Tavakkolizadeh wrote. It has been postulated that the normalization of insulin sensitivity after bypass types of bariatric procedures may be related to duodenal isolation and subsequent changes in incretins, glucagon-like peptide, and glucose-dependent insulinotrophic polypeptide following surgery.33,34

INDICATIONS
The National Institutes of Health (NIH) Consensus Development Panel35 has set forth guidelines for patients who may be considered eligible for bariatric surgery. Such individuals should be:

  • Well-informed and motivated
  • Have a BMI >40 kg/m²
  • Have acceptable risk for surgery
  • Have failed previous nonsurgical weight loss

Adults with a BMI >35 kg/m²who have serious comorbidities (eg, diabetes, OSA, obesity-related cardiomyopathy, severe joint disease) may also be candidates, according to the NIH. professional societies agree that bariatric surgery must be performed in conjunction with a comprehensive follow-up plan. As such, the American Society of Metabolic and Bariatric Surgeons (ASMBS) and the American College of Surgeons have guidelines for establishing Centers of Excellence for bariatric facilities.36

TYPES OF BARIATRIC PROCEDURES
Bariatric surgical procedures are malabsorptive or restrictive, depending on how they induce weight loss (Table 1). Vertical banded gastroplasty (VBG) and laparoscopic adjustable gastric banding (LAGB) are restrictive procedures and limit caloric intake by downsizing the stomach's reservoir capacity. These procedures are less complex and weight loss is more gradual. Malabsorptive procedures, such as jejunoileal bypass (JIB), biliopancreatic diversion (BPD), and duodenal switch operation (DS), shorten the length of the functional small intestine. These procedures can result in dramatic weight loss, however, significant metabolic complications can occur.

The Roux-en-Y gastric bypass (RYGB) has both a restrictive and malabsorptive component. It is primarily restrictive, as a small gastric pouch limits oral intake, but the small bowel reconfiguration provides additional mechanisms favoring weight loss, according to Drs. Mun and Tavakkolizadeh's report.

An article by Wittgrove et al stated that minimally invasive techniques were first used in bariatric surgery in the 1990s,37 and now an increasing number of laparoscopic RYGB and LAGB are being performed.

Procedure selection. LAGB and RYGB are the most commonly performed bariatric procedures. A 5-year trial by Angrisani et al compared the two procedures in 50 obese patients who had a mean BMI of 43 kg/m².38 That investigation found that laparoscopic RYGB (LRYGB) resulted in a loss of a greater percentage of excess body weight (67% vs 47%) and had fewer failures (4% vs 35%). A 14-study meta-analysis38 of clinical outcomes following LAGB and RYGB revealed advantages and disadvantages of RYGB:39

  • 1-year weight loss was superior (median difference 26%, 95% CI, 19–34)
  • Resolution of comorbidities was superior
  • Operative times and hospitalization were longer
  • Perioperative complications (9% vs 5%) were greater, but reoperation rates (16% vs 24%) were lower

Mortality was 0.06% and 0.17% for LAGB and RYGB, respectively. In summary, RYGB was associated with greater long-term success but higher short-term morbidity. Drs. Mun and Tavakkolizadeh wrote that patient preference, the institution, and expertise of the surgeons should determine the procedure selected.

RESTRICTIVE PROCEDURE OVERVIEW
VBG. Patients can be expected to have excess weight loss of up to 66% at 2 years, which decreases to 55% at 9 years, as per Pratt et al.40 Drs. Mun and Tavakkolizadeh wrote that effectiveness depends on the durability of the pouch and stoma size. VBG has been replaced largely by other procedures due to lack of sustained/desired weight loss as well as the high incidence of complications requiring revision (20% to 56%) Most revisions are for staple line disruption, stomal stenosis, band erosion, band disruption, pouch dilatation, vomiting, and gastroesophageal reflux disease.

LABG. (See sidebar, Brief Summary and History of Bariatric Surgery: Gastric Banding.) This restrictive procedure has been performed throughout Europe and Australia for almost a decade, however, it was not until June 2001 when the first adjustable band, LapBand (Allergan; Irvine, CA) was approved for US use. The Realize band (Ethicon Endo-Surgery, Inc; Somerville, NJ) is also available.47 Both use a soft, locking silicone ring connected to an infusion port placed in subcutaneous tissue. The port can be accessed with a syringe and needle, and saline injection reduces the band's diameter to increase restriction. The band is placed laparoscopically,48,49 and indications are similar to those of gastric bypass.35 (See sidebar, Comparison of the Lap-Band System and the Realize Band.)

Its simplicity and low complication rates have made LAGB popular.50-52 European and Australian data indicate a 15% to 20% loss of excess weight at 3 months, 40% to 53% at 1 year, and an eventual increase up to 45% to 58% after 2 years.53-57

Weight loss with this procedure is generally more gradual and less dramatic than with gastric bypass procedures, Drs. Mun and Tavakkolizadeh wrote. Successful long-term weight loss depends on follow-up and band adjustments. LAGB is also associated with improvements in comorbidities and quality of life.7,8,51,58-61

Sleeve gastrectomy. This technique was first used among patients with supermorbid obesity as a "first- stage surgery."62,63 A laparoscopic partial gastrectomy is performed, and most of the greater curvature of the stomach is removed. as described by Drs. Mun and Tavakkolizadeh, a small tubular stomach is created, which is resistant to stretching due to absence of fundus and devoid of ghrelin-producing cells. Reports have stated that sleeve gastrectomy is safer than gastric bypass, technically easier, avoids multiple anastomoses, reduces postoperative risk of internal herniation and protein and mineral malabsorption.64,65 A less technically challenging partial gastrectomy can be first performed, delaying the more technically rigorous laparoscopic Roux-en-Y gastric bypass or BPD until after patients have reached a lower weight,63 according to a report from Regan et al.

Regan found that patients lose about 33% excess weight in 1 year.63 Randomized studies comparing it to adjustable gastric banding have shown that sleeve gastrectomy results in better weight loss and hunger control at 1 and 3 years after surgery.66 Benefits have been partly attributed to better suppression of ghrelin versus gastric bypass,67 as discussed in a report by Karamankos.68

Intragastric balloon. Intragastric balloon (Bioenterics Intragastric Balloon, Inamed) is a temporary weight loss device for use in moderately obese individuals.69-72 A soft, saline-filled balloon is placed endoscopically, and it promotes a feeling of satiety and restriction. The device is not currently available in the United States. Evaluation in Europe and Brazil has shown mean excess weight loss to be 38% and 48% for 500- and 600-mL balloons, respectively.70 Weight loss may be transient as shown by Sallet et al, with only 26% of patients maintaining more than 90% of the excess weight loss over 1 year.71

Endoluminal vertical gastroplasty. This is an endoscopic method for suturing the stomach may have the potential to perform gastric restrictive procedures endoluminally.73

MALABSORPTIVE PROCEDURE OVERVIEW
Jejunoileal bypass. This was one of the first bariatric operations performed in 1969.74 It has been abandoned due to high complication rates and frequent need for revisional surgery.75-79 There are surviving patients who have undergone this procedure, and they should be monitored.

BPD. BPD consists of a partial gastrectomy and gastroileostomy with a long segment of Roux limb and a short common channel resulting in malnutrition.80 Reports reveal weight loss of up to 72% of excess weight through 18 years. Outcomes with a laparoscopic approach to BPD have shown acceptable outcomes,81 although high rates of protein malnutrition, anemia, diarrhea, and stomal ulceration are seen as discussed in a report by Marceau et al.82

BPD with duodenal switch (DS). BPD/DS is a variant of BPD and is primarily malabsorptive.83 Drs. Mun and Tavakkolizadeh wrote that a partial sleeve gastrectomy that preserves the pylorus is performed, and a Roux limb with a short common channel is created. This procedure has been advocated for patients with supermorbid obesity (BMI >50 kg/m²) and is associated with a lower incidence of stomal ulceration and diarrhea than BPD alone.84,85 It is not widely accepted as a first-line surgical treatment for morbid obesity in this country, according to Drs. Mun and Tavakkolizadeh.

MIXED PROCEDURES
RYGB. RYGB was developed in the 1960s,86 and many improvements have been made since that time. According to Drs. Mun and Tavakkolizadeh it is the most common bariatric procedure performed in the United States and is considered the gold standard. It is primarily a restrictive operation with a malabsorptive component that also contributes to weight loss. Sugerman et al reported that RYGB is superior to VBG in long-term weight reduction.41

Drs. Mun and Tavakkolizadeh describe the RYGB: Most commonly, the procedure is characterized by a small proximal gastric pouch divided and separated from the stomach remnant with drainage of food to the rest of the gastrointestinal tract via a tight stoma and a Roux-en-Y small bowel arrangement. The small pouch restricts caloric intake, and a larger gastric remnant becomes disconnected from the food stream. Secretion of gastric acid, pepsin, and intrinsic factor continues. The small intestine is divided distal to the ligament of Treitz and a proximal biliopancreatic limb that transports the secretions from the gastric remnant, liver, and pancreas is created. The Roux limb is anastomosed to the new gastric pouch and drains consumed food. The cut ends of the biliopancreatic limb and the Roux limb are then connected distally from the gastrojejunostomy. Digestion and absorption of nutrients occurs in the common channel where pancreatic enzymes and bile mix with ingested food. Although weight loss is mostly attributed to restriction, other mechanisms such as dumping syndrome, Roux limb length, and gut hormones play a role.87-91

RYGB can be performed laparoscopically and92 is associated with advantages such as lower incidence of incisional hernia, wound infection, faster recovery, and a shorter hospital stay.93-95

Excess weight loss with this procedure is, on average, 62% to 68% after the first year. Early weight loss is typically rapid, then plateaus after 1 to 2 years to an average of 50% to 75%.93,94,97,98 Research shows this to be an excellent tool for a permanent surgical weight loss. Improvement and/or resolution of comorbid conditions has also been well established.93,97-100

SUMMARY AND RECOMMENDATIONS
See sidebar, Medical Cost of Obesity May Be as High as $147 Billion Per Year. Surgical therapies cause restriction of caloric intake as well as malabsorption of nutrients. These procedures can enable patients to effectively lose weight and therefore improve associated comorbidities. Restrictive procedures are generally simpler, but they are also associated with less weight loss. Malabsorptive procedures are associated with significant metabolic complications but are highly effective. Today, Roux-en-Y gastric bypass is the most commonly performed procedure in this country.

Drs. Mun and Tavakkolizadeh concluded that evolving laparoscopic approaches to surgery, performed by well-trained surgeons can lower surgical pain, infectious and hernia complications, and allow for faster recovery. LABG is increasingly popular in the United States: it is a simple procedure, it is adjustable, reversible, and is associated with a very low mortality rate. It is important to note that many professional associations have released guidelines on the care of patients following weight loss surgery.

Edward C Mun, MD, FACS, is Assistant Professor of Surgery, Harvard Medical School, and a member of the ASMBS. He may be reached at emun@partners.org; emun@caregroup.harvard.edu; or phone: 617-667-3784. Ali Tavakkolizadeh, MD, is Associate Surgeon in the Department of Surgery at Brigham and Women's Hospital and can be reached at atavakkoli@partners.org; phone: 617-732-6337; or fax: 617-739-1728

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