BMJ  2006;333:900-903 (28 October), doi:10.1136/bmj.333.7574.900

Practice

ABC of obesity

Management: Part III—Surgery

professor of surgery and medicine in the department of surgery, SUNY Downstate Medical Center, New York.

Although surgery can be a potentially life extending treatment for obesity, most patients and doctors reject surgical intervention. Moreover, no national health budget or insurance can afford surgery on a very large scale. However, obesity surgery is a successful, validated, legitimate treatment and needs to be considered in some circumstances.

 

Preventive surgery

Healthcare workers and the public alike still lack awareness about the epidemiological consequences of and the severity of outcomes associated with pregnancy in obese women. Outcomes include fetal loss, malformations, intellectual impairment, lifelong psychosocial suffering, and programming of chronic metabolic diseases. People also lack awareness about the epigenetic transmission of obesity to their daughters, who themselves go on to become obese mothers.

View this table: [in this window] [in a new window]   Goal and methods of obesity surgery

 

Given the seriousness of the obesity epidemic, "preventive surgery" in obese young women may therefore be indicated when all else fails. Furthermore, such surgery can prevent the inexorable progression of obesity towards manifest comorbidity (such as diabetes, congestive heart failure, liver cirrhosis, and hypertension) and, ultimately, irreversible chronic disease and end organ failure.

View this table: [in this window] [in a new window]   Key prerequisites for obesity surgery

 

Obesity surgery entails a trade-off between the progressively debilitating intractable symptoms and chronic diseases associated with obesity and the side effects and complications of operations designed to create chronic (relative) undernutrition. Most obese adults who have chosen surgery and had complications (including death) have been satisfied with their choice because their lives as obese individuals were often not worth living.

Early obesity surgery can bring secondary health problems. Nevertheless, the extraordinary lifelong suffering imposed by the psychosocial sequelae of extreme childhood obesity cannot be underestimated: depression, anxiety, eating disorders, vocational and marital failure, and years of life lost. Mitigating the impairment of quality of life might well be the most important outcome measure used to evaluate treatments for childhood obesity. Thus, even surgery can be considered.

Behavioural surgery

The different types of operations (restrictive versus bypass) have different and substantive long term effects on eating (the most important of all activities of daily living)—thus the term "behavioural surgery."

Prerequisites for considering obesity surgery are extensive patient assessment and meticulous preoperative education. Identifying motivational factors driving the patient to maintain obesity is more important before surgery than before non-surgical treatments because of the greater stakes involved.

"Successful" surgery has more potential for achieving meaningful, durable weight loss, and "failure" after surgery has much graver consequences. Assessment and education should allow improved allocation of patients to specific types of operations and postoperative care.

This is the fifth article in the series

Without understanding or accepting the severity of obesity and the risks of obesity (or "bariatric") surgery—or the "success" and risks of non-surgical alternatives—doctors and other health workers cannot adequately advise patients in their choice of treatment

Compared with usual care, obesity surgery has recently been shown to reduce all cause mortality, mortality due to cancer, and cardiovascular mortality

Obstructive and diversionary operations

As with most surgery, bariatric surgery should preferably be performed laparoscopically and only by surgeons with sufficient training and expertise. Surgeon and hospital case volume affect perioperative safety: the more cases, the better the outcomes. Because of the adverse interaction between obesity and inflammatory and physiological processes related to incision size and an open abdomen, obese patients benefit more from laparoscopic approaches than other patients, regardless of operation or condition being treated.

View larger version (14K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Ratio of observed to expected inhospital mortality for patients aged 55 years, according to bariatric surgical volume (adapted from Nguyen et al. Ann Surg 2004;240: 586-94[ISI][Medline])

 

View larger version (23K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Roux-en-Y gastric bypass with pouch separated from stomach (laparoscopic technique)

 

View this table: [in this window] [in a new window]   Outcomes of 24 166 patients having obesity surgery in 93 US academic hospitals by volume, 1992-2002

 

The simplest operation is laparoscopic placement of an inflatable band encircling the top 5% of the stomach, creating a proximal "pouch." During follow-up a physician can inject or withdraw saline to adjust the diameter of the band, which obstructs or restricts the passage of mainly solids (high energy liquids readily pass through). Discomfort or involuntary vomiting, or both, occur after poor chewing (such as from ill fitting dentures), rapid eating, exceeding pouch capacity (about 20 ml), or drinking shortly after eating. Repeated vomiting may cause the pouch to stretch, allowing weight gain.

View larger version (24K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Inflammatory response (C reactive protein) to open v laparoscopic gastric bypass (adapted from Nguyen et al. J Am Coll Surg 2002;194: 562)

 

View larger version (33K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Adjustable gastric band showing injection or withdrawal of saline to adjust diameter of band

 

Complex laparoscopic operations combine obstruction and diversion (or bypass), disconnecting the proximal pouch from the stomach and attaching it to a limb of the small bowel (known as the Roux-en-Y gastric bypass). Variations of gastric bypass—such as the biliopancreatic diversion and long limb gastric bypass, which leave less absorptive small bowel in continuity—are reserved for heavier patients with more intractable disease and severe binge eating disorder. Heavier patients (with a very high body mass index—calculated as dividing the weight in kilograms by the height in metres squared) have binge eating disorder.

View larger version (27K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Biliopancreatic diversion with sleeve resection of greater curvature and post-pyloric, duodeno-ileal anastomosis ("duodenal switch")

 

During the first eight to 12 months after bypass operations, weight loss is caused by obstruction of nutrient flow. After the stomach pouch and its enterostomy stretch, continued and maintained weight loss is caused partly by altered processing and/or absorption of nutrients and partly by decreased appetite or "hunger" owing to the rush of nutrients into the limb of the small bowel.

View this table: [in this window] [in a new window]   Mechanisms of obesity surgery

 

The generic types of operations have different effects on eating behaviour, the key element of obesity, so results, risks, and benefits can vary substantially. Obstructive operations require frequent outpatient visits (monthly during the first 12-18 months) to optimise weight loss. Diversionary operations (requiring clinic visits every three months during the first year) consistently achieve greater and better maintained weight loss than gastric banding. Their greater risk of long term complications is abrogated by one yearly clinic visit with blood testing for vitamin and mineral deficiencies.

View this table: [in this window] [in a new window]   Instructions on eating for patients who have had obstructive stomach surgery

 

Indications

Both surgical and non-surgical treatments have improved over the past 25 years. Diet and exercise programmes have been developed and four new drugs have been launched. The safety and efficacy of surgery has improved remarkably. Calculations of cost per kilogram of maintained weight loss have shown a "break even" comparison after less than four years—results that favour surgery, if costs of drugs, supplements, complications and side effects are taken into account. For ethical and scientific reasons, randomisation studies of surgery and non-surgical treatment cannot be done. Furthermore, it is very difficult to retain participants in non-surgical treatment long enough to provide meaningful comparable outcome data.

View this table: [in this window] [in a new window]   Suitability for referral for surgery

 

The widely accepted indication for surgery since the 1960s has been a body mass index (BMI) of 40 or 35-40 with obesity related comorbidity. Recommended requirements for surgery include that patients should have seriously tried to lose weight by other means. In fact, most patients seeking surgery have tried to lose weight five to seven times. Candidates should not have behavioural conditions likely to interfere with postoperative care. Hospitals should have a multidisciplinary team with appropriate expertise for evaluating, operating on, and managing severely obese patients. Age criteria are usually a minimum of 20-25 years and a maximum of 60-65.

View this table: [in this window] [in a new window]   Conditions improved or prevented by obesity

 

With improved safety—owing to the laparoscopic approach and the relatively simple and reversible gastric band technique—indications are expanding, with trends towards accepting patients with a lower BMI (30-35) and a wider age range (from adolescence (12-17 years) to 70 years and above) in appropriate candidates. Weight regain after purely restrictive operations can be treated by using "rescue" medication (which interferes with the absorption of lipids (orlistat) and/or carbohydrates (acarbose)) or, ultimately, by adding a diversionary procedure.

Outcomes

Success is difficult to define because of disparate opinions among patients, doctors, the insurance industry, and tax payers. The difficulty is compounded by the lack of information about optimal amounts and rates of weight loss: how much is "enough" and how is enough determined? Actuarial data define "desirable" weight standards for the general population, but insufficient and conflicting data are available for those who have lost weight voluntarily and maintained the loss.

Indications for obesity surgery must be viewed in the context of results of alternative, non-surgical treatments and their costs and risks, and the patient's assessment of quality of life. This supports the importance of educating and assessing patients. Data showing superior efficacy of obesity surgery over optimal non-surgical treatment have been unequivocal since the early 1960s, when such surgery began

High risk patients, especially men with a BMI of >55, need complex surgery and may benefit from a staged approach, starting with a simple restrictive operation, followed as needed (depending on weight loss maintenance) by a diversionary stage

Rather than focusing on weight loss as the primary outcome measure, it is more appropriate to evaluate improvements in comorbidities and quality of life, although in patients with a BMI of > 35 mortality (including operative) is lower in patients having operations than in those receiving usual care. Numerous observational and case studies over four decades have consistently found improved established risk factors for premature death, reduction of comorbidity, and improved quality of life after surgical weight loss.

View larger version (29K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Obesity trends in United States, by body mass index, 1986-2000. Adapted from Sturm R. Arch Intern Med 2003;163: 2146-8[Abstract/Free Full Text]

 

View this table: [in this window] [in a new window]   Conclusions

 

At the same time, obesity surgery is associated with mortality, morbidity, complications, side effects, and unwanted sequelae, all of which must be included in the risk-benefit analysis. Mortality statistics need stratification by generic type of operation, age, sex, and comorbidity profile. However, it is difficult preoperatively to predict long term outcomes for the various types of operations. Social factors such as having a stable life situation (being married, having a job) and being white predict favourable outcomes, whereas binge eating or overconsumption of "soft calories" (calories derived from liquids or soft foods such as ice cream and chocolate) may be detrimental.

View larger version (19K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Estimated numbers of obesity operations in United States, 1992-2003. Adapted from Steinbrook R. N Engl J Med 2004;350: 1075-9[Free Full Text]

 

View this table: [in this window] [in a new window]   Adverse effects of obesity surgery

 

Deficiencies of vitamins and minerals are among the most common and troublesome long term complications of obesity surgery. They are more common after diversionary operations, due to poor digestion and malabsorption from exclusion of the stomach and shortened continuous small bowel. Vitamin and mineral deficiency is preventable with assiduous monitoring and adequate supplementation, both of which require the patient's cooperation, which often is difficult to achieve.

View this table: [in this window] [in a new window]   Predictors of response

 

As with all surgery, the proficiency and dedication of the surgeons and their teams are critical. Obesity surgery has become the victim of its own success owing to improved perioperative results, general awareness of the seriousness of the disease, and substantial increases in the numbers of obese patients, which has led to the rapid recruitment of surgeons who are not yet sufficiently trained. Currently, strict guidelines and performance evaluations are being developed as part of quality assurance efforts and demands from third party payers.

---

The ABC of Obesity is edited by Naveed Sattar (nsattar{at}clinmed.gla.ac.uk), professor of metabolic medicine, and Mike Lean, professor of nutrition, University of Glasgow. The series will be published as a book by Blackwell Publishing in early 2007.

Competing interests: John G Kral is a member of the North American Association for the Study of Obesity and the American Society for Bariatric Surgery. For series editors' competing interests, see the first article in this series.

The photograph is published with permission from Constantine Manos/Magnum Photos.

References

• Christou NV, Sampalis JS, Liberman M, Look D, Auger S, McLean AP, et al. Surgery decreases long term mortality, morbidity and healthcare use in morbidly obese patients. Ann Surg 2004;240: 416-24.[ISI][Medline] • Sjöström L, Lindroos AK, Peltonen M, Torgerson J, Bouchard C, Carlsson B, et al. Lifestyle, diabetes, and cardiovascular risk factors 10 years after bariatric surgery. N Engl J Med 2004;351: 2683-93.[Abstract/Free Full Text] • Sugerman HG, Kral JG. Evidence-based medicine reports on bariatric surgery: a critique. Int J Obes 2005;29: 735-45.[CrossRef][ISI][Medline] • Kral JG. Preventing and treating obesity in girls and young women to curb the epidemic. Obes Res 2004;12: 1539-46.[ISI][Medline] • Livingston EH, Martin RF, eds. Bariatric surgery. Surg Clin N Am 2005;85(4): 665-874. • Sjöström L. Soft and hard endpoints over 5-18 years in the intervention trial Swedish obese subjects. Obesity Reviews 2006;7(suppl 2): 27.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

Related Article

Reconstructive surgery is often needed after obesity surgery

Chidi C Ekwobi and Adam R Greenbaum
BMJ 2006 333: 1022. [Extract] [Full Text] [PDF]

This article has been cited by other articles:

• Ekwobi, C. C, Greenbaum, A. R (2006). Reconstructive surgery is often needed after obesity surgery. BMJ 333: 1022-1022 [Full text]  

Rapid Responses:

Read all Rapid Responses

Satisfied with their choice?

Iain R Crossingham
bmj.com, 28 Oct 2006 [Full text]

Post-bariatric reconstructive surgery

Chidi C Ekwobi, et al.
bmj.com, 30 Oct 2006 [Full text]

Surgery for obesity saves lives?

Jøran Hjelmesæth
bmj.com, 21 Nov 2006 [Full text]

Re: Satisfied with their choice?

John G. Kral, M.D., Ph.D.
bmj.com, 11 Dec 2006 [Full text]

Re: Surgery for obesity saves lives?

John G. Kral, M.D., Ph.D.
bmj.com, 14 Dec 2006 [Full text]