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Bariatric surgery
Oesophagus & Stomach
Bariatric surgery
Why surgery? Faced with the prospect of shifting an extra stone or two, most of us would be able to buckle down to some serious dieting, perhaps bolstered with a bit of help from anti-obesity drugs. Clinical trials show that in a highly selected cohort of patients who can (a) demonstrate initial weight loss and (b) tolerate the side effects, these drugs can result in a 10% decrease in body weight. If you weigh 13 stones, this will get you down to a more acceptable 11 and a half stones. However, if you weigh 30 stones, medical treatment is still going to leave you weighing in at 27 stones, which is frankly a waste of time and resources. The often quoted improvements in medical problems resulting from 10% weight loss have never been demonstrated in these very heavy surgical candidates. The two main trials comparing surgery with medical and life-style interventions show startling results in favour of surgery. A randomized controlled trial from Australia compared outcomes after intensive medical treatment (very low-calorie diet, anti-obesity drugs and a behavioural programme) with laparoscopic gastric banding.1 Although results were similar at 6 months, excess weight lost after 2 years was 18% in the medical group and 68% in those who had undergone surgery. This point is borne out by the Swedish Obese Subjects Study, the largest long-term observational study of obesity treatments.2 After 10 years, with 99.9% follow-up, no sustained weight loss was observed in the medically treated group (in fact, these patients had actually gained weight), whereas patients with a gastric bypass had maintained an average loss of 25% of starting body weight. A 40–50% reduction in deaths from myocardial infarction and cancer was also noted in the surgical group. Bariatric surgery may indeed be viewed as a desperate and drastic step, but patients at the more extreme end of the obesity spectrum are in desperate need of some drastic action to help them to turn their lives around.
David Kerrigan
Abstract Obesity is a progressive disease that shortens life expectancy and is associated with a wide range of medical problems ranging from diabetes and heart disease through to infertility and cancer. Losing weight can significantly improve or cure these conditions and helps to reduce the chances of future health problems developing. Anti-obesity drugs result in a 10% fall in body weight, but this degree of weight loss has never been shown to confer significant clinical benefit in patients with a body mass index exceeding 40 kg/m2, for whom bariatric surgery is indicated. Gastric banding is less effective than other procedures and it takes longer for target weight loss to be reached, but it is the safest, quickest and least expensive bariatric procedure. Gastric bypass is a more effective option, as weight loss is more rapid and is generally complete within a year. However, the drawback is that the bypass carries more risk. It also induces a mild degree of malabsorption, and affects satiety signalling between the gut and brain. The duodenal switch (DS) shares some features with the gastric bypass in that both operations prevent calorie absorption, although this effect is much more marked after a DS. The advantage of this approach is that excellent, reliable weight loss can be achieved without the need to reduce the stomach (and thus portion) size dramatically. However, patients need to adhere to a strict high-protein diet with vitamin supplementation if nutritional problems are to be avoided.
Keywords bariatric surgery; diabetes; duodenal switch; gastric banding;
Who is eligible for surgery?
gastric bypass; laparoscopic; obesity; weight loss
There is no standard weight over which you become a suitable candidate for surgery. This is because the taller you are, the more weight you can carry safely. To allow for this, we use body mass index (BMI), although other indicators such as waist circumference can also be useful. Surgery is indicated in those with a BMI over 40 kg/m2, a level of obesity (known as morbid obesity) that is strongly associated with a risk of serious health problems. If medical problems that may improve after weight loss already exist, the minimum cut-off for surgery is lowered to a BMI of 35 kg/m2 or greater (Table 1).
Obesity is a progressive disease that shortens life expectancy and is associated with a wide range of serious medical problems ranging from diabetes and heart disease through to infertility and cancer. Losing weight can significantly improve or cure these conditions and in the long-term help to reduce the chances of future health problems developing. Weight reduction also has significant physical and psychological benefits, with increased energy, mobility and improved self-esteem. Successful weight loss helps people to turn the clock back and re-engage with their lives and families, often for the first time in years.
How does bariatric surgery work? Many patients with a severe weight problem do not have good control of eating. Often they do not experience the normal reduction in appetite after a meal, and they continue to eat more calories than their body requires. Surplus calories are stored in the body in the form of fat, to be used at a later time. Bariatric surgery seeks to redress these imbalances in several ways: by limiting portion size, by interfering with the absorption of calories, and by affecting satiety signalling between the gut and the brain.
David Kerrigan MD(Hons) FRCS FRCSEd is Medical Director and Consultant Bariatric Surgeon at Gravitas, and Honorary Senior Lecturer in Surgery at the University of Liverpool, Liverpool, UK. Conflicts of interest: none declared.
SURGERY 26:11
448
© 2008 Elsevier Ltd. All rights reserved.
Oesophagus & Stomach
Gastric banding is less effective than other procedures in terms of weight loss and it takes longer for target weight loss to be reached (about 55% of excess weight is lost over 2 years), but it is the safest, quickest and least expensive bariatric procedure available. The chances of major perioperative complications leading to death are about 1 in 2000, which is very low for an abdominal operation. The band is fully reversible. Usually, only one night is spent in hospital. Band tightness is adjusted in the outpatient clinic by injecting fluid into the band through a small access port hidden deep to the skin of either the abdominal or chest wall. The procedure takes about 2 minutes and does not require an anaesthetic. Some units use radiological screening, but experience shows that this is unnecessary. Over several months, the degree of band inflation is gradually increased until it is tight enough to offer optimal control of portion size, while still allowing the patient to eat most normal foods. It is important not to over-tighten the band. Although weight loss may be quicker in the short term, it is believed that an over-tight band may increase the risk of longer-term complications such as band slippage, pouch dilatation or even band erosion through the gastric wall. Over a 5-year period, serious band-related complications that may require further surgery or even band removal occur in about 10–15% of patients.
Conditions that may improve with weight loss Diabetes High blood pressure Angina Hypercholesterolaemia Asthma Sleep apnoea Painful joints and arthritis Acid reflux Underactive thyroid Weight-related depression Polycystic ovaries and infertility Table 1
There are three main surgical options available in the UK. In experienced units, all are performed usually using laparoscopic surgery, which, apart from better cosmesis and quicker recovery, has been associated with a lower risk of late postoperative complications.
Adjustable gastric banding Gastric bypass
Gastric banding is an effective surgical procedure used to help overweight people achieve significant and long-term weight loss. A soft, adjustable collar (the band) is clipped around the top of the stomach laparoscopically, creating a small pouch above (Figure 1). Some stitches are usually placed between the fundus and the gastric pouch to reduce the chance of the band slipping out of position. When inflated, the band will grip and squeeze gently on the stomach wall. This pressure delays the passage of solid food through the upper part of the stomach. The resulting hold-up creates a sensation of fullness (often called restriction) with even very small portions. The band forces patients into chewing food very carefully and eating very slowly, but it also makes them feel full quickly and reduces appetite.
Also known as the Roux-en-Y gastric bypass (Figure 2) the gastric bypass is an operation that has stood the test of time. It is the most widely performed bariatric procedure in the USA. The bypass encourages weight loss in several ways, reducing portion size and calorie absorption, but also by affecting satiety signalling between the gut and brain. Key points are summarized in Table 2. In a similar way to gastric banding, portion size is controlled physically by the creation of a small pouch of stomach at the bottom end of the gullet. Additionally, a mild degree of malabsorption is induced by separating swallowed food from the digestive juices for a while. This is achieved by creating a divided stomach pouch, completely separate from the distal stomach, and anastomosis of an (alimentary) limb of jejunum on to the
Adjustable gastric band
Roux-en-Y gastric bypass
Figure 1
SURGERY 26:11
Figure 2
449
© 2008 Elsevier Ltd. All rights reserved.
Oesophagus & Stomach
Less serious side effects of gastric bypass include dumping syndrome (fainting, cramps and diarrhoea after eating sweet foods), although this can be an advantage in sweet eaters (see below). Although most patients are delighted with the speed of weight loss after gastric bypass, rapid weight loss can bring about its own problems, such as excess loose skin folds, temporary hair thinning and gallstone formation (10% of all bypass patients subsequently require cholecystectomy in our unit). Weight regain can also gradually occur in a minority (about 10% over 10 years).
Gastric bypass Faster, more reliable and more effective weight loss than banding. 0.25% mortality, 2% leak rate. Patients do not have to be superobese. Serious nutritional problems are rare, although regular blood tests are required. Once they have recovered from the operation and adjusted their eating habits, patients can enjoy a wide range of normal foods. Portions are small and there is a mild reduction in food absorption. Forces patients to chew carefully and eat slowly. Dumping syndrome (fainting, diarrhoea and cramps) can occur after even moderate amounts of sugary food. Diarrhoea rare. Not reversible. 3 nights in hospital after laparoscopic surgery.
Duodenal switch The duodenal switch (DS) procedure is a more recent addition to the bariatric surgeon’s repertoire. Even though it is technically more complex than gastric banding and gastric bypass, it is still performed laparoscopically by expert teams. The DS shares some features in common with the gastric bypass in that both operations rely on surgically separating food from the digestive juices, thereby preventing calorie absorption. The major difference is that with a DS the patient is left with a much shorter length of bowel with which to absorb food (just 100 cm for fat and starch, and about 300 cm for protein absorption). Most of the weight loss after a DS is thought to result from reduced calorie absorption. Key points about the procedure are summarized in Table 3. The great advantage of this approach is that excellent, reliable weight loss can be achieved without the need to reduce stomach (and thus portion) size dramatically. Part of the stomach is removed, rather than bypassed, which converts the upper two-thirds of the stomach into a long, thin tube. This creates a stomach pouch about 15 times larger than that after a band or gastric bypass. This part of the operation is also known as a sleeve gastrectomy (Figure 3). Established DS patients can usually eat a fairly normal-sized meal (unlike band and gastric bypass patients who are always limited to smaller portions). The larger stomach, which empties normally through the pylorus, also prevents some of the problems associated with the gastric bypass such as dumping syndrome and the need for vitamin B12 injections.
Table 2
pouch using either a circular or linear stapling technique. In recent years, a more vertically orientated pouch (which excludes most of the thin-walled, elastic fundus) has been recommended to avoid late pouch dilatation and weight regain. To complete the Roux-en-Y reconstruction, the first 75–150 cm of jejunum (containing the biliopancreatic juices) is re-anastomosed to the alimentary limb 75–150 cm distal to the gastric pouch. The exact length of small bowel bypassed can be varied depending on the BMI of the patient, but the malabsorptive effect is usually mild. Apart from vitamin B12 deficiency (about 35–50% of patients eventually require 3-monthly B12 injections), clinically significant postoperative malabsorptive sequelae are uncommon. The gastric fundus is the site of production of the appetitestimulating hormone ghrelin. Ghrelin levels fall after Roux-en-Y gastric bypass, whereas levels of appetite-suppressing gut hormones such as peptide YY, glucagon-like peptide 1 and oxytomodulin rise. These hormonal changes undoubtedly contribute to the reduction in appetite and portion size seen after surgery.3 With several different ways of producing weight loss, the gastric bypass is usually a more effective operation than gastric banding (typically 70% of excess weight is lost). Weight loss is more rapid and is generally complete within a year. However, the big drawback is that gastric bypass carries more risk. Unlike a band, the bypass carries the risk of anastomotic leakage. Usually, this means a return to theatre for lavage and drainage (attempts at sutured repair are usually futile), with insertion of a feeding jejunostomy downstream of the leak. Patients can be in hospital for weeks or even months waiting for the leak to heal. This serious complication occurs in about 2–3% of cases and accounts for most of the perioperative mortality after gastric bypass. Leading centres report a mortality rate of between 1 in 200 and 1 in 400 after gastric bypass, although this figure can be higher in less expert hands. Other potentially serious perioperative risks include deep vein thrombosis/pulmonary embolism (2–3%), and early postoperative stenosis of the gastrojejunal anastomosis requiring endoscopic balloon dilatation.
SURGERY 26:11
Duodenal switch Stomach 15 times larger than after either gastric banding or gastric bypass. Portion size near-normal after 12 months. Mainly works by preventing calorie absorption. Much higher risk of serious nutritional problems unless great care is taken with a strict postoperative diet. Lifetime commitment to high-protein diet (100 g/day) essential. Vitamin and mineral replacement crucial – at least five tablets per day required to avoid problems such as osteoporosis. Loose, foul-smelling stools if fat ingestion is high. Faster, more reliable and more effective weight loss than banding. 0.5% mortality, 2% leak rate. Not reversible. 3 nights in hospital are required after laparoscopic surgery. Table 3
450
© 2008 Elsevier Ltd. All rights reserved.
Oesophagus & Stomach
(see above). This only comes on after ingestion of sugary carbohydrates (chocolate, ice cream, sweets and full-sugar soft drinks) and so it can act as a perverse incentive to put patients off sugar and keep their weight loss on track. If a chocoholic opts for a band, they will have to rely on good old-fashioned will-power instead!
Duodenal switch
Redo (revisional) surgery Revisional surgery is performed when complications occur after bariatric surgery or to treat weight regain. It is the most complex kind of bariatric surgery and, compared with the initial operation, carries about double the risk of major postoperative complications and death. Revisional surgery should only be performed in highly specialized and experienced units where it can usually be carried out using laparoscopic techniques, even when the original operation was performed by a traditional open technique.
Removed portion of stomach (sleeve gastrectomy)
Aftercare The most important part of healthy and successful weight loss is the quality of the aftercare service provided. Research and experience suggest that patients with the best follow-up and support have the best outcomes. The operation is the easy bit – the hard work comes later. A good quality multidisciplinary team of surgeons, nurses, dieticians and support staff is essential to help patients get the best results from bariatric surgery. It is essential to form a lifelong relationship with patients to help them maintain the health improvements they have gained from surgery. Experience shows that those who can work with their operation and maintain lifestyle and dietary changes will get the most out of their surgery. ◆
Figure 3
The disadvantage of the DS technique is that it requires a much larger intestinal bypass. Not absorbing fat and carbohydrates can be beneficial in terms of weight loss, but failure to absorb enough protein is potentially very dangerous and can lead to serious nutritional complications, hospital admission and, in severe cases, death. To compensate for this, it is essential that patients keep to a very high-protein diet indefinitely after surgery. They also need to take much more in the way of vitamin and mineral tablets, particularly calcium and vitamin D. Failure to absorb fat tends to lead to loose, smelly stools and wind (steatorrhoea). Apart from these special problems, most of the other risks of the DS are similar to those described for gastric bypass.
References 1 O’Brien PE, Dixon JB, Laurie C, et al. Treatment of mild to moderate obesity with laparoscopic adjustable gastric banding or an intensive medical program: a randomized trial. Ann Intern Med 2006; 144: 625–33. 2 Sjöström L, Narbro K, Sjöström CD, et al. Effects of bariatric surgery on mortality in Swedish obese subjects. N Engl J Med 2007; 357: 741–52. 3 Cummings DE, Shannon MH. Ghrelin and gastric bypass: is there a hormonal contribution to surgical weight loss? J Clin Endocrinol Metab 2003; 88: 2999–3002. 4 Hess DS, Hess DW. Biliopancreatic diversion with a duodenal switch. Obes Surg 1998; 8: 267–82. 5 Pories WJ, Swanson MS, MacDonald KG, et al. Who would have thought it? An operation proves to be the most effective therapy for adult-onset diabetes mellitus. Ann Surg 1995; 222: 339–52.
Special considerations Patients with diabetes Bariatric surgery is an extremely effective treatment for type 2 diabetes. Current evidence suggests that gastric bypass and DS operations give the best chance of diabetes cure (remission). Between 70 and 90% of patients can expect to come off all treatment and yet still maintain a normal blood sugar level.4,5 Remarkably, improvements are often seen within days of surgery. It is thought that re-routing the food away from the upper intestine after a bypass or DS stimulates a gut hormone response (either via incretins, which stimulate insulin release, or by affecting a proposed but as yet unidentified antiincretin system) that immediately counteracts the diabetes. Band patients can also see improvements in diabetes, but fewer patients go into complete remission, and it tends to take much longer before a beneficial effect is noted.
Further reading British Obesity Surgery Patient Association. Available from: http://www. bospa.org (accessed July 2008). National Institute for Health and Clinical Excellence. Obesity surgery guidance. Available from: http://www.nice.org.uk/guidance/CG43/ guidance, December 2006 (accessed July 2008). Weight loss surgery information & support. Available from: http://www. wlsinfo.org.uk (accessed July 2008).
Sweet eaters Regardless of the type of surgery, patients will get a disappointing result if they continue to eat large amounts of sweets and chocolate afterwards. It is hard to give up the things we love to eat even if we know they are bad for us. However, the gastric bypass has an unpleasant side effect known as dumping syndrome
SURGERY 26:11
451
© 2008 Elsevier Ltd. All rights reserved.
Bariatric surgery
Why surgery? Faced with the prospect of shifting an extra stone or two, most of us would be able to buckle down to some serious dieting, perhaps bolstered with a bit of help from anti-obesity drugs. Clinical trials show that in a highly selected cohort of patients who can (a) demonstrate initial weight loss and (b) tolerate the side effects, these drugs can result in a 10% decrease in body weight. If you weigh 13 stones, this will get you down to a more acceptable 11 and a half stones. However, if you weigh 30 stones, medical treatment is still going to leave you weighing in at 27 stones, which is frankly a waste of time and resources. The often quoted improvements in medical problems resulting from 10% weight loss have never been demonstrated in these very heavy surgical candidates. The two main trials comparing surgery with medical and life-style interventions show startling results in favour of surgery. A randomized controlled trial from Australia compared outcomes after intensive medical treatment (very low-calorie diet, anti-obesity drugs and a behavioural programme) with laparoscopic gastric banding.1 Although results were similar at 6 months, excess weight lost after 2 years was 18% in the medical group and 68% in those who had undergone surgery. This point is borne out by the Swedish Obese Subjects Study, the largest long-term observational study of obesity treatments.2 After 10 years, with 99.9% follow-up, no sustained weight loss was observed in the medically treated group (in fact, these patients had actually gained weight), whereas patients with a gastric bypass had maintained an average loss of 25% of starting body weight. A 40–50% reduction in deaths from myocardial infarction and cancer was also noted in the surgical group. Bariatric surgery may indeed be viewed as a desperate and drastic step, but patients at the more extreme end of the obesity spectrum are in desperate need of some drastic action to help them to turn their lives around.
David Kerrigan
Abstract Obesity is a progressive disease that shortens life expectancy and is associated with a wide range of medical problems ranging from diabetes and heart disease through to infertility and cancer. Losing weight can significantly improve or cure these conditions and helps to reduce the chances of future health problems developing. Anti-obesity drugs result in a 10% fall in body weight, but this degree of weight loss has never been shown to confer significant clinical benefit in patients with a body mass index exceeding 40 kg/m2, for whom bariatric surgery is indicated. Gastric banding is less effective than other procedures and it takes longer for target weight loss to be reached, but it is the safest, quickest and least expensive bariatric procedure. Gastric bypass is a more effective option, as weight loss is more rapid and is generally complete within a year. However, the drawback is that the bypass carries more risk. It also induces a mild degree of malabsorption, and affects satiety signalling between the gut and brain. The duodenal switch (DS) shares some features with the gastric bypass in that both operations prevent calorie absorption, although this effect is much more marked after a DS. The advantage of this approach is that excellent, reliable weight loss can be achieved without the need to reduce the stomach (and thus portion) size dramatically. However, patients need to adhere to a strict high-protein diet with vitamin supplementation if nutritional problems are to be avoided.
Keywords bariatric surgery; diabetes; duodenal switch; gastric banding;
Who is eligible for surgery?
gastric bypass; laparoscopic; obesity; weight loss
There is no standard weight over which you become a suitable candidate for surgery. This is because the taller you are, the more weight you can carry safely. To allow for this, we use body mass index (BMI), although other indicators such as waist circumference can also be useful. Surgery is indicated in those with a BMI over 40 kg/m2, a level of obesity (known as morbid obesity) that is strongly associated with a risk of serious health problems. If medical problems that may improve after weight loss already exist, the minimum cut-off for surgery is lowered to a BMI of 35 kg/m2 or greater (Table 1).
Obesity is a progressive disease that shortens life expectancy and is associated with a wide range of serious medical problems ranging from diabetes and heart disease through to infertility and cancer. Losing weight can significantly improve or cure these conditions and in the long-term help to reduce the chances of future health problems developing. Weight reduction also has significant physical and psychological benefits, with increased energy, mobility and improved self-esteem. Successful weight loss helps people to turn the clock back and re-engage with their lives and families, often for the first time in years.
How does bariatric surgery work? Many patients with a severe weight problem do not have good control of eating. Often they do not experience the normal reduction in appetite after a meal, and they continue to eat more calories than their body requires. Surplus calories are stored in the body in the form of fat, to be used at a later time. Bariatric surgery seeks to redress these imbalances in several ways: by limiting portion size, by interfering with the absorption of calories, and by affecting satiety signalling between the gut and the brain.
David Kerrigan MD(Hons) FRCS FRCSEd is Medical Director and Consultant Bariatric Surgeon at Gravitas, and Honorary Senior Lecturer in Surgery at the University of Liverpool, Liverpool, UK. Conflicts of interest: none declared.
SURGERY 26:11
448
© 2008 Elsevier Ltd. All rights reserved.
Oesophagus & Stomach
Gastric banding is less effective than other procedures in terms of weight loss and it takes longer for target weight loss to be reached (about 55% of excess weight is lost over 2 years), but it is the safest, quickest and least expensive bariatric procedure available. The chances of major perioperative complications leading to death are about 1 in 2000, which is very low for an abdominal operation. The band is fully reversible. Usually, only one night is spent in hospital. Band tightness is adjusted in the outpatient clinic by injecting fluid into the band through a small access port hidden deep to the skin of either the abdominal or chest wall. The procedure takes about 2 minutes and does not require an anaesthetic. Some units use radiological screening, but experience shows that this is unnecessary. Over several months, the degree of band inflation is gradually increased until it is tight enough to offer optimal control of portion size, while still allowing the patient to eat most normal foods. It is important not to over-tighten the band. Although weight loss may be quicker in the short term, it is believed that an over-tight band may increase the risk of longer-term complications such as band slippage, pouch dilatation or even band erosion through the gastric wall. Over a 5-year period, serious band-related complications that may require further surgery or even band removal occur in about 10–15% of patients.
Conditions that may improve with weight loss Diabetes High blood pressure Angina Hypercholesterolaemia Asthma Sleep apnoea Painful joints and arthritis Acid reflux Underactive thyroid Weight-related depression Polycystic ovaries and infertility Table 1
There are three main surgical options available in the UK. In experienced units, all are performed usually using laparoscopic surgery, which, apart from better cosmesis and quicker recovery, has been associated with a lower risk of late postoperative complications.
Adjustable gastric banding Gastric bypass
Gastric banding is an effective surgical procedure used to help overweight people achieve significant and long-term weight loss. A soft, adjustable collar (the band) is clipped around the top of the stomach laparoscopically, creating a small pouch above (Figure 1). Some stitches are usually placed between the fundus and the gastric pouch to reduce the chance of the band slipping out of position. When inflated, the band will grip and squeeze gently on the stomach wall. This pressure delays the passage of solid food through the upper part of the stomach. The resulting hold-up creates a sensation of fullness (often called restriction) with even very small portions. The band forces patients into chewing food very carefully and eating very slowly, but it also makes them feel full quickly and reduces appetite.
Also known as the Roux-en-Y gastric bypass (Figure 2) the gastric bypass is an operation that has stood the test of time. It is the most widely performed bariatric procedure in the USA. The bypass encourages weight loss in several ways, reducing portion size and calorie absorption, but also by affecting satiety signalling between the gut and brain. Key points are summarized in Table 2. In a similar way to gastric banding, portion size is controlled physically by the creation of a small pouch of stomach at the bottom end of the gullet. Additionally, a mild degree of malabsorption is induced by separating swallowed food from the digestive juices for a while. This is achieved by creating a divided stomach pouch, completely separate from the distal stomach, and anastomosis of an (alimentary) limb of jejunum on to the
Adjustable gastric band
Roux-en-Y gastric bypass
Figure 1
SURGERY 26:11
Figure 2
449
© 2008 Elsevier Ltd. All rights reserved.
Oesophagus & Stomach
Less serious side effects of gastric bypass include dumping syndrome (fainting, cramps and diarrhoea after eating sweet foods), although this can be an advantage in sweet eaters (see below). Although most patients are delighted with the speed of weight loss after gastric bypass, rapid weight loss can bring about its own problems, such as excess loose skin folds, temporary hair thinning and gallstone formation (10% of all bypass patients subsequently require cholecystectomy in our unit). Weight regain can also gradually occur in a minority (about 10% over 10 years).
Gastric bypass Faster, more reliable and more effective weight loss than banding. 0.25% mortality, 2% leak rate. Patients do not have to be superobese. Serious nutritional problems are rare, although regular blood tests are required. Once they have recovered from the operation and adjusted their eating habits, patients can enjoy a wide range of normal foods. Portions are small and there is a mild reduction in food absorption. Forces patients to chew carefully and eat slowly. Dumping syndrome (fainting, diarrhoea and cramps) can occur after even moderate amounts of sugary food. Diarrhoea rare. Not reversible. 3 nights in hospital after laparoscopic surgery.
Duodenal switch The duodenal switch (DS) procedure is a more recent addition to the bariatric surgeon’s repertoire. Even though it is technically more complex than gastric banding and gastric bypass, it is still performed laparoscopically by expert teams. The DS shares some features in common with the gastric bypass in that both operations rely on surgically separating food from the digestive juices, thereby preventing calorie absorption. The major difference is that with a DS the patient is left with a much shorter length of bowel with which to absorb food (just 100 cm for fat and starch, and about 300 cm for protein absorption). Most of the weight loss after a DS is thought to result from reduced calorie absorption. Key points about the procedure are summarized in Table 3. The great advantage of this approach is that excellent, reliable weight loss can be achieved without the need to reduce stomach (and thus portion) size dramatically. Part of the stomach is removed, rather than bypassed, which converts the upper two-thirds of the stomach into a long, thin tube. This creates a stomach pouch about 15 times larger than that after a band or gastric bypass. This part of the operation is also known as a sleeve gastrectomy (Figure 3). Established DS patients can usually eat a fairly normal-sized meal (unlike band and gastric bypass patients who are always limited to smaller portions). The larger stomach, which empties normally through the pylorus, also prevents some of the problems associated with the gastric bypass such as dumping syndrome and the need for vitamin B12 injections.
Table 2
pouch using either a circular or linear stapling technique. In recent years, a more vertically orientated pouch (which excludes most of the thin-walled, elastic fundus) has been recommended to avoid late pouch dilatation and weight regain. To complete the Roux-en-Y reconstruction, the first 75–150 cm of jejunum (containing the biliopancreatic juices) is re-anastomosed to the alimentary limb 75–150 cm distal to the gastric pouch. The exact length of small bowel bypassed can be varied depending on the BMI of the patient, but the malabsorptive effect is usually mild. Apart from vitamin B12 deficiency (about 35–50% of patients eventually require 3-monthly B12 injections), clinically significant postoperative malabsorptive sequelae are uncommon. The gastric fundus is the site of production of the appetitestimulating hormone ghrelin. Ghrelin levels fall after Roux-en-Y gastric bypass, whereas levels of appetite-suppressing gut hormones such as peptide YY, glucagon-like peptide 1 and oxytomodulin rise. These hormonal changes undoubtedly contribute to the reduction in appetite and portion size seen after surgery.3 With several different ways of producing weight loss, the gastric bypass is usually a more effective operation than gastric banding (typically 70% of excess weight is lost). Weight loss is more rapid and is generally complete within a year. However, the big drawback is that gastric bypass carries more risk. Unlike a band, the bypass carries the risk of anastomotic leakage. Usually, this means a return to theatre for lavage and drainage (attempts at sutured repair are usually futile), with insertion of a feeding jejunostomy downstream of the leak. Patients can be in hospital for weeks or even months waiting for the leak to heal. This serious complication occurs in about 2–3% of cases and accounts for most of the perioperative mortality after gastric bypass. Leading centres report a mortality rate of between 1 in 200 and 1 in 400 after gastric bypass, although this figure can be higher in less expert hands. Other potentially serious perioperative risks include deep vein thrombosis/pulmonary embolism (2–3%), and early postoperative stenosis of the gastrojejunal anastomosis requiring endoscopic balloon dilatation.
SURGERY 26:11
Duodenal switch Stomach 15 times larger than after either gastric banding or gastric bypass. Portion size near-normal after 12 months. Mainly works by preventing calorie absorption. Much higher risk of serious nutritional problems unless great care is taken with a strict postoperative diet. Lifetime commitment to high-protein diet (100 g/day) essential. Vitamin and mineral replacement crucial – at least five tablets per day required to avoid problems such as osteoporosis. Loose, foul-smelling stools if fat ingestion is high. Faster, more reliable and more effective weight loss than banding. 0.5% mortality, 2% leak rate. Not reversible. 3 nights in hospital are required after laparoscopic surgery. Table 3
450
© 2008 Elsevier Ltd. All rights reserved.
Oesophagus & Stomach
(see above). This only comes on after ingestion of sugary carbohydrates (chocolate, ice cream, sweets and full-sugar soft drinks) and so it can act as a perverse incentive to put patients off sugar and keep their weight loss on track. If a chocoholic opts for a band, they will have to rely on good old-fashioned will-power instead!
Duodenal switch
Redo (revisional) surgery Revisional surgery is performed when complications occur after bariatric surgery or to treat weight regain. It is the most complex kind of bariatric surgery and, compared with the initial operation, carries about double the risk of major postoperative complications and death. Revisional surgery should only be performed in highly specialized and experienced units where it can usually be carried out using laparoscopic techniques, even when the original operation was performed by a traditional open technique.
Removed portion of stomach (sleeve gastrectomy)
Aftercare The most important part of healthy and successful weight loss is the quality of the aftercare service provided. Research and experience suggest that patients with the best follow-up and support have the best outcomes. The operation is the easy bit – the hard work comes later. A good quality multidisciplinary team of surgeons, nurses, dieticians and support staff is essential to help patients get the best results from bariatric surgery. It is essential to form a lifelong relationship with patients to help them maintain the health improvements they have gained from surgery. Experience shows that those who can work with their operation and maintain lifestyle and dietary changes will get the most out of their surgery. ◆
Figure 3
The disadvantage of the DS technique is that it requires a much larger intestinal bypass. Not absorbing fat and carbohydrates can be beneficial in terms of weight loss, but failure to absorb enough protein is potentially very dangerous and can lead to serious nutritional complications, hospital admission and, in severe cases, death. To compensate for this, it is essential that patients keep to a very high-protein diet indefinitely after surgery. They also need to take much more in the way of vitamin and mineral tablets, particularly calcium and vitamin D. Failure to absorb fat tends to lead to loose, smelly stools and wind (steatorrhoea). Apart from these special problems, most of the other risks of the DS are similar to those described for gastric bypass.
References 1 O’Brien PE, Dixon JB, Laurie C, et al. Treatment of mild to moderate obesity with laparoscopic adjustable gastric banding or an intensive medical program: a randomized trial. Ann Intern Med 2006; 144: 625–33. 2 Sjöström L, Narbro K, Sjöström CD, et al. Effects of bariatric surgery on mortality in Swedish obese subjects. N Engl J Med 2007; 357: 741–52. 3 Cummings DE, Shannon MH. Ghrelin and gastric bypass: is there a hormonal contribution to surgical weight loss? J Clin Endocrinol Metab 2003; 88: 2999–3002. 4 Hess DS, Hess DW. Biliopancreatic diversion with a duodenal switch. Obes Surg 1998; 8: 267–82. 5 Pories WJ, Swanson MS, MacDonald KG, et al. Who would have thought it? An operation proves to be the most effective therapy for adult-onset diabetes mellitus. Ann Surg 1995; 222: 339–52.
Special considerations Patients with diabetes Bariatric surgery is an extremely effective treatment for type 2 diabetes. Current evidence suggests that gastric bypass and DS operations give the best chance of diabetes cure (remission). Between 70 and 90% of patients can expect to come off all treatment and yet still maintain a normal blood sugar level.4,5 Remarkably, improvements are often seen within days of surgery. It is thought that re-routing the food away from the upper intestine after a bypass or DS stimulates a gut hormone response (either via incretins, which stimulate insulin release, or by affecting a proposed but as yet unidentified antiincretin system) that immediately counteracts the diabetes. Band patients can also see improvements in diabetes, but fewer patients go into complete remission, and it tends to take much longer before a beneficial effect is noted.
Further reading British Obesity Surgery Patient Association. Available from: http://www. bospa.org (accessed July 2008). National Institute for Health and Clinical Excellence. Obesity surgery guidance. Available from: http://www.nice.org.uk/guidance/CG43/ guidance, December 2006 (accessed July 2008). Weight loss surgery information & support. Available from: http://www. wlsinfo.org.uk (accessed July 2008).
Sweet eaters Regardless of the type of surgery, patients will get a disappointing result if they continue to eat large amounts of sweets and chocolate afterwards. It is hard to give up the things we love to eat even if we know they are bad for us. However, the gastric bypass has an unpleasant side effect known as dumping syndrome
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