Obesity

Surgery for obesityKevin Robertson

AbstractObesity is an increasing problem worldwide. Dieting and available

medications are relatively ineffective, especially for the morbidly

obese. However, bariatric surgery has been shown to provide long

lasting reduction of obesity related non-insulin dependent diabetes

mellitus, hypertension and hyperlipidaemia. Furthermore, longevity

was improved. Motivated patients of bMi greater than 40 (or 35 with

co-morbidities) can be considered for surgery. Procedures are cat-

egorized as restrictive, reducing dietary intake, and malabsorptive,

resulting in reduced nutrient absorption. Weight loss usually continues

for 2 years after which it will plateau. Average excess weight loss is

40−70%. Most studies suggest better results for malabsorptive pro-

cedures, however, these carry a greater mortality risk than simpler

restrictive procedures. Laparoscopic surgery has significantly reduced

peri-operative morbidity but, in the morbidly obese, both surgery and

anaesthesia remain challenging. the major cause of operative mortal-

ity is pulmonary thromboembolism and anti-coagulant prophylaxis is

imperative. After surgery a proportion of patients may require plastic

surgery to excess skin folds. Demand for bariatric surgery is likely to

increase with growing evidence showing benefits for both patients and

society as a whole.

Keywords obesity; bariatric; surgery; laparoscopic; gastric band; gastric

bypass

The healthcare implications of obesity are enormous; life expec-tancy of a morbidly obese 25-year-old male is reduced by 22%, or 12 years, compared to a normal weight male.1 Diet therapies and pharmacological agents are relatively ineffective in the lon-ger term, especially for the morbidly obese who generate the greatest costs through disability and secondary diseases like dia-betes.2 In contrast, there is good evidence that surgery can be effective.

A meta-analysis of 22,094 surgically treated patients has dem-onstrated that non-insulin dependent diabetes (NIDDM) was completely resolved in 76.8% of patients, hyperlipidaemia was

Kevin Robertson MD FRCS is a Consultant Surgeon in the Lister

Department of Surgery at Glasgow Royal Infirmary and also at Stobhill

Hospital, Glasgow, UK. He qualified from Glasgow University and

trained in general surgery with interests in oesophago-gastric surgery

and laparoscopic surgery. Competing interests: none declared.

MeDiCiNe 34:12 52

improved in more than 70% and hypertension was resolved in 61.7%.1 Studies comparing treated and matched control patients have even shown reduced mortality for surgically treated patients.3 Furthermore the medical benefits of surgery seem to be long-lasting.4

Which patients are eligible?

NICE has suggested that patients with a BMI in excess of 40 and those with a BMI greater than 35 with related co-morbidities can be considered for surgical treatment.2

However, not all patients meeting these criteria want, or should have, surgery. Patient selection remains one of the most difficult aspects of providing a bariatric surgical service. Many forms of surgery can be ‘beaten’ by poorly motivated patients who do not comply with post-surgical dietary restrictions. Sur-gery is not a ‘quick fix’ and patients should understand that they will live with its effects for life.

Types of surgery

Surgery can be categorized as ‘restrictive’ or ‘malabsoptive’. Restrictive surgery aims to reduce the volume eaten at each meal, but does not alter the route ingested food takes through the gut. Examples include gastric banding and vertical band gastroplasty. Malabsoptive surgery will usually include a restrictive element but also includes surgical modification of the gastrointestinal tract to reduce nutrient absorption, nor-mally bypassing part of the small intestine. Examples include gastric bypass and duodenal switch. Most bariatric procedures will result in 40‐70% excess weight loss at about 2 years after which weight usually plateaus. Evidence suggests malabsorp-tive procedures result in greater weight loss and greater impact on co-morbid conditions, with less tendency to regain in the long term.1

Influence of laparoscopy

All bariatric procedures can now be performed laparoscopically and there is good evidence that this reduces morbidity with reduced post-operative pain and earlier mobilization, shorter periods of sick leave and fewer incisional hernias.5,6 Paradoxi-cally, internal hernias may be more frequent as the laparoscopic technique may produce fewer adhesions.7

Surgery

The most frequently performed procedures in the UK are laparoscopic gastric banding and laparoscopic gastric bypass.

Gastric banding involves placing a prosthetic inflatable band around the upper part of the stomach (Figure 1). By accessing a subcutaneous port, band volume can be adjusted varying the size of communication, and rate of drainage, between upper gastric pouch and the remaining stomach. It is relatively simple to per-form with low peri-operative morbidity/mortality.1,8 Weight loss is less rapid than with bypass and motivation is imperative as low residue, high calorie fluids will pass through the band with ease. Additionally, the presence of a prosthetic device carries risks of infection, erosion and migration.8

1 © 2006 Published by elsevier Ltd.

Obesity

Gastric bypass − a small proximal gastric pouch is isolated from the remainder of the stomach and anastomosed to a long roux-en-y of small intestine such that pancreato-biliary secretions only mix with food in the gastro-enterostomy limb some 120 cm, or further, from the gastrojejunostomy. Bypass of the duodenum and proximal small intestine means patients will usually require supplements of iron, calcium, B12 and vitamins.9 It has been suggested dietary compliance is improved by ‘mild dumping’ symptoms induced by ingestion of low residue, sugary foods.9 However, this surgery is technically more demanding; anasto-moses may leak, staple lines may bleed and internal hernias can occur. Operative mortality is 5‐10 times greater than for gastric banding.1,8

The major peri-operative hazard is pulmonary thromboem-bolism, accounting for 50% of deaths in one review of 3464 bariatric cases, and prophylaxis is imperative.10 Patients are also at risk from technical failings at surgery such as anastomotic leaks (0.5‐2%), bleeding and bowel injury.10

Nutritional review

Many morbidly obese patients have bizarre food choices and eating patterns, and these can become more restricted after bariatric surgery. During weight loss post-operatively it is usu-ally recommended to take a micronutrient supplement which provides at least the daily recommended intake (DRI) for all essential micronutrients. Dietitians can advise. Following mal-absorption procedures, dietary requirements may exceed DRIs for life, demanding long-term supplements. Regular nutritional review (e.g. every 6‐12 months) with full biochemical and haematological investigation is recommended. Bariatric surgery does not directly address the hypothalamic drive to eat, although effects on gut hormones may increase satiety. Drugs therapy to promote satiety may still be needed.

Figure 1 Adjustable gastric band. the white tubing (exiting the frame

to the left), connects to a subcutaneous port which can be accessed to

vary the internal diameter of the band. the band is inserted opened but

is shown in the closed position with the closing mechanism at 6 o’clock

on the band circumference.

MeDiCiNe 34:12 52

Further considerations

Anaesthesia (Figure 2) requires good evaluation of the reper-cussions of morbid obesity on cardiovascular and respiratory systems as well as the technical difficulties of intubation, ventila-tion and obesity-altered pharmacokinetics.11,12

Patients may lose so much weight that excessive skin folds may form for which they may wish plastic surgery. This should not be considered until weight has been stable for at least a year.

Many morbidly obese patients have personality problems and psychological disturbances. Some of these may be improved by bariatric surgery, but some may be exacerbated. Access to experienced psychological counselling may be valuable.

The future

Bariatric surgery in the UK is less well developed than else-where, partly due to funding issues but also because obesity continues to be viewed as self inflicted and low priority. How-ever, that may change with increasing evidence that treated patients subsequently use less healthcare resources and enjoy improved employment prospects, benefiting society as a whole.1,3 ◆

ReFeReNceS

1 buchwald H, Avidar y. braunald e et al. bariatric surgery:

a systematic review and meta-analysis. JAMA 2004; 292: 1724–37.

2 National institute for Clinical excellence (NiCe). Guidance on the use

of surgery to aid weight reduction for people with morbid obesity.

Technology Appraisal Guidance No. 46. issued July 2002. Available

at: http://www.nice.org.uk [Accessed 25 July 2006].

Figure 2 Anaesthetized patient awaiting bariatric surgery. some of

the surgical and anaesthetic difficulties can be envisioned from

this man’s size.

2 © 2006 Published by elsevier Ltd.

Obesity

3 Christou N V, sampalis J s, Liberman M et al. surgery decreases

long-term mortality, morbidity, and health care use in morbidly

obese patients. Ann Surg 2004; 240: 416–24.

4 sjostrom L, Lindroos A, Peltonen M et al. Lifestyle, diabetes, and

cardiovascular risk factors 10 years after bariatric surgery. N Eng J

Med 2004; 351: 2683–93.

5 Nguyen N t, Lee s, Goldman C et al. Comparison of pulmonary

function and post-operative pain after laparoscopic versus open

gastric bypass: a randomised trial. J Am Coll Surg 2001; 192: 469–76.

6 Nguyen N t, Goldman C, Rosenquist C J et al. Laparoscopic versus

open gastric bypass: a randomised study of outcomes, quality of

life, and costs. Ann Surg 2001; 234: 279–89.

7 Westling A, Gustavsson s. Laparoscopic versus open roux-en-y gastric

bypass: a prospective, randomised trial. Obes Surg 2001; 11: 284–92.

MeDiCiNe 34:12 52

8 O’brien P e, Dixon J b, brown W. Obesity is a surgical disease:

overview of obesity and bariatric surgery. ANZ J Surg 2004; 74:

200–4.

9 Parini U, Nebiolo P e, eds. Bariatric surgery: multidisciplinary

approach and surgical techniques. societa Valdostana di Chirurgia,

2004.

10 Podnos y D, Jimenez J C, Wilson s e et al. Complications after

laparoscopic gastric bypass: a review of 3464 cases. Arch Surg

2003; 138: 957–61.

11 Pieracci F M, barie P s, Pomp A. Critical care of the bariatric patient.

Critical Care Med 2006; 34: 1796–804.

12 Munsch y, saynard P. the anaesthetists point of view in the

surgical treatment of pathological obesity. Ann Chir 1997; 51:

183–8.

3 © 2006 Published by elsevier Ltd.