Outcome of laparoscopic duodenal switch for morbid obesity

Transcription

1 Original article Outcome of laparoscopic duodenal switch for morbid obesity C. J. Magee, J. Barry, J. Brocklehurst, S. Javed, R. Macadam and D. D. Kerrigan Gravitas, PO Box 3627, Bourne End SL8 5GQ, UK Correspondence to: Mr D. D. Kerrigan ( Background: The aim of this study was to determine the safety and efficacy of laparoscopic duodenal switch (LDS) as a treatment option in a selected group of patients with morbid obesity. Methods: This retrospective analysis of a prospective database assessed the frequency of all complications and alterations in weight, body mass index (BMI), co-morbidity and quality of life. Results: One hundred and twenty-one patients underwent LDS between April 2003 and March Median preoperative weight was 160 kg and median BMI 55 kg/m 2. All procedures were performed laparoscopically. The in-hospital mortality rate was zero. No ileoduodenal anastomotic stenosis was encountered. There were four clinical leaks (3 3 per cent) managed by laparoscopic drainage and placement of a feeding jejunostomy. Median percentage excess weight loss was 75 per cent at 12 months and 90 per cent at 24 months. Thirty-six of 40 diabetic patients had complete resolution of diabetes within 1 year. There were significant improvements in other obesity-related co-morbidity. Only a few patients developed postoperative protein deficiency, and fat-soluble vitamin deficiencies were easily managed with oral supplementation. Conclusion: The LDS procedure is a safe and effective treatment for morbid obesity and its associated co-morbidity in selected patients. Presented in part to the 14th World Congress of the International Federation for the Surgery of Obesity and Metabolic Diseases, Paris, France, August 2009, and the Annual Scientific Meeting of the Association of Upper Gastrointestinal Surgeons of Great Britain and Ireland, Nottingham, UK, September 2009, and published in abstract form as Obes Surg 2009; 19: 1042 and Br J Surg 2009; 96(Suppl 4): 137 Paper accepted 20 August 2010 Published online 21 October 2010 in Wiley Online Library ( DOI: /bjs.7291 Introduction Despite the relentless increase in the prevalence of obesity worldwide and a greater acceptance of bariatric surgery as the best current treatment 1,2, there is still no clear consensus regarding the optimal surgical approach. Laparoscopic adjustable gastric banding is performed widely in Europe and Australia, but weight loss is considered by many to be inferior to that achieved with malabsorptive procedures such as laparoscopic Roux-en-Y gastric bypass 3 and laparoscopic duodenal switch (LDS) 4. Roux-en-Y gastric bypass is popular 5 but can lead to disappointing long-term weight loss as a significant number of patients regain weight with time 6,7. The duodenal switch is a hybrid bariatric procedure combining a moderate restrictive element (sleeve gastrectomy) with significant malabsorption provided by a biliopancreatic diversion. LDS has been shown to give better weight loss than gastric banding and Roux-en-Y gastric bypass, particularly in the superobese 8,9. However, there is concern that this excellent weight loss may come at the price of an unacceptably high incidence of nutritional complications. The aim of this study was to determine the safety and efficacy of LDS as a treatment option in a selected group of patients. Methods Eligibility for bariatric surgery was based on National Institute for Health and Clinical Excellence criteria 10 which stipulate a body mass index (BMI) threshold of at least 40 kg/m 2 (or 35 kg/m 2 in the presence of established co-morbidity likely to improve with weight loss). Patients with a BMI exceeding 50 kg/m 2 could access bariatric surgery as first-line treatment, but other candidates were 2010 British Journal of Surgery Society Ltd British Journal of Surgery 2011; 98: 79 84

2 80 C. J. Magee, J. Barry, J. Brocklehurst, S. Javed, R. Macadam and D. D. Kerrigan required to undergo an initial period of medical obesity management. Both private and publically funded patients were studied after undergoing a standard bariatric multidisciplinary team assessment, which included an hour-long presentation and discussion regarding the nature, risks, sideeffects, complications and limitations of various bariatric procedures. Patients were offered a choice of primary laparoscopic bariatric surgery (laparoscopic adjustable gastric banding, laparoscopic Roux-en-Y gastric bypass, sleeve gastrectomy and LDS). The operation to be performed was decided jointly by the patient and the bariatric surgeon after taking into account various factors including, but not limited to, patient preference, attitude to risk and expectations of weight loss. In addition, patients who selected LDS as their preferred choice underwent a more detailed assessment (lifestyle, psychological and dietary) to ensure that they could adhere to the proscriptive postoperative LDS protocol. In particular, they were required to complete a 2-week food diary while on a trial of the mandatory highprotein diet ( g protein per day). Patients who have had a LDS procedure need to comply with a fairly intensive multivitamin and mineral replacement regimen. Thus, a history of poor compliance with current medication was viewed as a contraindication to LDS. Outcomes and complications were recorded after surgery and in subsequent outpatient follow-up, and held in a confidential database. Data collected included percentage excess weight loss, BMI, quality-of-life scores, improvement in co-morbidity (defined by an observed reduction in treatment for co-morbidity), complications and nutritional deficiencies. The Bariatric Analysis and Reporting Outcome System (BAROS) score 11 was calculated for the first 100 patients. Duodenal switch procedure A similar technique to that described by Matteoti and Gagner 12 was used, with a handsewn ileoduodenostomy and totally stapled 75 per cent sleeve gastrectomy and ileoileostomy (Fig. 1). In the early part of the present series the ileum was transected 250 cm proximal to the ileocaecal valve; this was increased to 300 cm following early experience of protein malabsorption. All patients received venous thromboembolic prophylaxis consisting of low molecular weight heparin before surgery and for 3 weeks afterwards 13. Contrast studies were not performed routinely. Free fluids were commenced on the first day after operation. A puréed diet was maintained for 3 4 weeks and then A B C Fig. 1 Anatomy of the duodenal switch. The greater curvature of the stomach is removed (hatched area). The ileum is divided 300 cm proximal to the ileocaecal junction (C) and the remnant ileum reanastomosed 100 cm proximal to the ileocaecal junction (B). The duodenum is divided and anastomosed to the previously divided ileum (C). The alimentary limb is from point C to point B; the biliopancreatic limb is from the second part of the duodenum (A) to point B. The common channel is from point B to the ileocaecal junction. Reproduced from BMJ 2009; 339: b3402 with permission soft diet for a further 3 4 weeks before a normal diet was introduced. Long-term intensive postoperative dietetic input was reinforced by written information. All patients received 3 months of ranitidine 300 mg/day, together with daily multivitamins and four soluble Cacit D3 sachets (Warner Chilcott, Larne, UK), or an equivalent preparation, each containing 500 mg calcium and 10 µg vitamin D. Vitamin D and A insufficiency on this basic replacement regimen was treated with high-dose supplementation (vitamin D 5000 units daily, vitamin A units daily). Follow-up by the bariatric multidisciplinary team was performed at 6 weeks, quarterly for the first 2 years and then at 6-monthly intervals. Biochemical assessment, including renal and liver profile, total protein, albumin, globulin, calcium, haemoglobin A1c, parathormone, iron, ferritin, vitamin B12, vitamin D, zinc and magnesium, was carried out at regular intervals. Vitamin A and international normalized ratio (INR, as an indirect measure of vitamin K) were measured annually. Routine dual-energy X-ray absorptiometry was not used. As a BMI exceeding 60 kg/m 2 is associated with a significant increase in operative morbidity and mortality 14,a staged LDS approach was used in these heavier patients. Initial laparoscopic sleeve gastrectomy was followed after A C B

3 Laparoscopic duodenal switch for morbid obesity 81 approximately 12 months by a completion biliopancreatic diversion with duodenal switch. Statistical analysis Values are presented as median (range). The Mann Whitney U test was used for statistical analysis and P < was considered statistically significant. Statistical analysis was performed by means of the statistical package SPSS version 16.0 (SPSS, Chicago, Illinois, USA). Results Between April 2003 and March 2009, 121 consecutive patients (72 women, 49 men) with a median age of 44 (25 62) years underwent LDS. Median preoperative weight and BMI were 160 (92 249) kg and 55 (38 83) kg/m 2 respectively. There was no significant difference in age or BMI between men and women (median BMI 55 kg/m 2 for both), but the men were significantly heavier (169 versus 146 kg; P < 0 001). Median follow-up was 46 (12 80) months. After one year, follow up was 96 per cent, but fell to 70 per cent after five years. Operation and learning curve All operations were performed laparoscopically with no conversions to open surgery. The median hospital stay was 3 (3 8) days. LDS was performed by two experienced consultant bariatric surgeons, each with experience of over 200 laparoscopic Roux-en-Y gastric bypasses before performing LDS. One surgeon had performed 75 LDS procedures and the other 46. Three major non-fatal complications occurred in the first 25 patients operated on by each surgeon. The leak rate reduced from 6 per cent in the first 50 patients to 1 per cent in the subsequent 71. Major complications There was no in-hospital, 30-day or 90-day mortality. Four patients (3 3 per cent) developed a postoperative leak. One leak resulted from iatrogenic disruption of the handsewn ileoduodenal anastomosis during the passage of a bougie to ensure anastomotic patency (a technique that has now been abandoned). The anastomosis was refashioned (side-to-side handsewn) under an unavoidable degree of tension and subsequently developed a leak and an enterocutaneous fistula distal to the anastomosis; the fistula was managed successfully by surgical closure after maturation. Two patients developed staple-line disruption of the sleeve gastrectomy high on the neo-greater curve immediately distal to the gastro-oesophageal junction, and a fourth patient developed a minor duodenal stump leak. All patients were initially managed by laparoscopy, washout and placement of a feeding jejunostomy. One patient with a healed gastric tube leak was given supplementary outpatient enteral feeding via a nasojejunal tube. This patient died from aspiration pneumonia 4 months after surgery. No postoperative symptomatic venous thromboembolism (deep vein thrombosis and/or pulmonary embolism) was encountered. Three patients (2 5 per cent) had minor wound infections. Two patients (1 7 per cent) early in the series developed a port-site hernia. Three patients (2 5 per cent) developed symptomatic gallstones. Postoperative weight loss and obesity-related co-morbidity Median weight loss, calculated as percentage excess weight loss based on an ideal BMI of 25 kg/m 2, was 75 (33 123) per cent at 1 year (121 patients), increasing to 90 (49 131) per cent at 2 years (107 patients) (Fig. 2). Weight loss was well maintained up to 5 years: 90 (65 123) per cent at 3 years (89 patients), 93 (69 119) per cent at 4 years (59 patients) and 94 (77 120) per cent at 5 years (26 patients). There were clinically significant improvements in all weight-related co-morbidities (Table 1). Thirty-six of 40 patients with diabetes mellitus were in remission (defined as euglycaemic and off medication) at 12 months. Twentyseven achieved remission within 7 days of surgery and a further nine patients thereafter. Despite a protein-rich diet and nutritional supplementation, six patients developed transient protein deficiency (serum albumin less than 30g/l) of whom four had severe hypoalbuminaemia (albumin below 25 g/l) and required supplementary enteral feeding (Table 2). All four patients responded to treatment, with normal albumin levels maintained on oral diet within 2 weeks. Table 1 Resolution and improvement of obesity-related co-morbidity No. of patients (n = 121) No. showing remission No. showing improvement Diabetes 40 (33 1) 36 (90) 0 (0) Hypertension 58 (47 9) 23 (40) 11 (19) Sleep apnoea 25 (20 7) 11 (44) 2 (8) Degenerative joint pain 46 (38 0) 2 (4) 19 (41) Asthma 22 (18 2) 3 (14) 7 (32) Dyslipidaemia 30 (24 8) 10 (33) 1 (3) Reflux 13 (10 7) 3 (23) 3 (23) Depression 36 (29 8) 8 (22) 4 (11) Values in parentheses are percentages.

4 82 C. J. Magee, J. Barry, J. Brocklehurst, S. Javed, R. Macadam and D. D. Kerrigan Excess weight loss (%) Time after surgery (years) Fig. 2 Box and whisker plots of percentage excess weight loss following laparoscopic duodenal switch. Median (horizontal line within box), interquartile range (box), minimum and maximum values within 1 5 the interquartile range (error bars), and outliers (circles) are shown. An excess weight loss of 100 per cent means that a body mass index (BMI) of 25 kg/m 2, the upper limit of normal, has been reached. If a BMI of less than 25 kg/m 2 is attained, excess weight loss is greater than 100 per cent Table 2 Malabsorptive consequences following surgery Deficiency Year 1 (n = 121) Year 2 (n = 107) Year 3 (n = 89) Year 4 (n = 59) Iron 27 (22 3) 8 (7 5) 3 (3) 0 (0) Zinc 30 (24 8) 14 (13 1) 0 (0) 0 (0) Folate 14 (11 6) 6 (5 6) 0 (0) 0 (0) Vitamin B12 6 (5 0) 5 (4 7) 1 (1) 0 (0) VitaminA 0(0) 6(5 6) 0 (0) 7 (12) Vitamin D 19 (15 7) 14 (13 1) 31 (35) 24 (41) Hypoalbuminaemia (< 30 g/l) 6 (5 0) 4 (3 7) 0 (0) 0 (0) Values in parentheses are percentages. Includes patients with transient deficiency during a given year. At 4 years after surgery a proportion of patients had biochemical deficiency of vitamin A (12 per cent) and vitamin D (41 per cent) despite standard multivitamin and mineral supplementation. Four patients presenting with symptomatic vitamin A deficiency (night blindness) confirmed on blood tests were started on high-dose supplementation. A further seven patients had biochemical evidence of vitamin A deficiency without symptoms. The onset of vitamin A deficiency tended to be several years after surgery (Table 2), underlining the importance of careful long-term monitoring of fat-soluble vitamin levels after LDS. There were no pathological fractures secondary to bone demineralization in this series. The first 100 patients were invited to complete a BAROS assessment, of whom 67 0 per cent responded. Quality of life had improved in 98 per cent of respondents, with 85 per cent reporting very good or excellent outcomes. Discussion The ideal bariatric procedure should have an acceptably low complication rate, result in sustained and significant weight loss, improve obesity-related co-morbidity and be suitable for most patients. A universally applicable procedure may not exist and patients should be offered a procedure tailored to their needs. In carefully selected and counselled patients, the LDS procedure is a safe, durable and extremely effective treatment for morbid obesity and its associated metabolic complications. With careful follow-up and early diagnosis, nutritional complications respond promptly to simple measures. Fears regarding the potential drawbacks of LDS seem overstated and its more widespread use can be considered. Roux-en-Y gastric bypass remains the most commonly performed bariatric procedure in North America 5 but is less reliable in superobese patients (BMI over 50 kg/m 2 ), with one in five patients experiencing treatment failure 15. In contrast, LDS has been shown to be superior to laparoscopic Roux-en-Y gastric bypass in achieving sustained long-term weight loss (particularly in the superobese) 8. Consequently, it has been proposed that superobesity is one possible indication for LDS. Selection criteria in the present series were not limited to superobesity and allowed for a degree of patient preference, yet the weight loss reported was greater than that documented by Hess and Hess (80 per cent excess weight loss at 2 years) 16 and Anthone and colleagues (69 and 73 per cent excess weight loss at 1 and 3 years respectively) 17. The superiority of the present results may reflect the strict assessment of suitability for LDS based on lifestyle and dietary factors, not just on BMI, or perhaps the degree of close follow-up. The range of preoperative co-morbidity reported here is similar to that in other series 18,19. Significant postoperative effects were seen on obesity-related co-morbidity. Thirtysix of 40 patients with preoperative diabetes mellitus had

5 Laparoscopic duodenal switch for morbid obesity 83 complete resolution of diabetes, being euglycaemic and off medication often within 1 week of surgery. Hypertension, sleep apnoea, gastro-oesophageal reflux and dyslipidaemia also improved following surgery. The present data show that LDS is technically demanding, even in the hands of experienced laparoscopic bariatric surgeons. Staple-line and anastomotic leakage occurred more frequently after the first 50 procedures thanexpectedafterlaparoscopicroux-en-y gastric bypass. The leak rate subsequently decreased to a more acceptable 1 per cent after the learning curve. Overall rates of morbidity and mortality compare favourably with published values 8,9,12,17,20. Extended use of postoperative low molecular weight heparin 13 prevented venous thromboembolism, a significant cause of death following bariatric surgery 21. The duodenal switch modification is reported to reduce the risk of marginal ulceration compared with a standard biliopancreatic diversion 16, but postoperative acid suppression was still used routinely. In this series a less efficacious H 2 -receptor antagonist was preferred over a proton-pump inhibitor, to preserve at least some acid secretion and thus promote a degree of pepsinogen cleavage and protein predigestion in the gastric sleeve. In theory, this should allow protein absorption in the alimentary limb in addition to the common channel. The nutritional consequences of surgical malabsorption are potentially severe, and this concern may be contributing to the slow adoption of LDS 17. Patients are at risk of protein malnutrition and need to consume g protein daily to maintain protein levels 22,23. All four patients who developed severe hypoalbuminaemia (albumin below 25 g/l) responded to temporary enteral feeding and none requested or required reversal of the LDS on clinical or nutritional grounds. Fat-soluble vitamin deficiencies are common following LDS and make monitoring of postoperative levels mandatory. The incidence of vitamin A deficiency (12 per cent) and vitamin D deficiency (41 per cent) was lower than that reported by Slater and colleagues (70 and 57 per cent respectively) 24. Nevertheless, the present results have led to a change in hospital postoperative protocol to include routine high-dose vitamin D3 (5000 units daily) and extra vitamin A (by doubling the dose of multivitamins). It is striking that 85 per cent of patients reported a very good or excellent quality of life after surgery. The ability to eat a near-normal portion as well as a wide range of normal solid foods contributes to patient satisfaction. However, the relatively low 67 0 per cent response rate among the first 100 patients questions whether these results are applicable to the entire group. The highly specialized nature of LDS surgery means that the study patients came from a geographically disparate area, which raises the possibility that some late complications (treated by local surgeons) may have been missed. However, this seems unlikely given the very high proportion of patients in regular contact with the specialist team. Perhaps surprisingly, most patients did not experience severe diarrhoea (typically patients pass 2 3 soft stools each morning), although a few patients were dissatisfied owing to abdominal bloating, malodorous flatus and steatorrhoea 18. Acknowledgements The authors declare no conflict of interest. References 1 James PT, Rigby N, Leach R; International Obesity Task Force. The obesity epidemic, metabolic syndrome and future prevention strategies. Eur J Cardiovasc Prev Rehabil 2004; 11: McPherson K, Marsh T, Brown M. Tackling Obesities: The Future Choices Modelling Future Trends in Obesity & Their Impact on Health (2nd edn). The Stationery Office: London, Nguyen NT, Slone JA, Nguyen XM, Hartman JS, Hoyt DB. A prospective randomized trial of laparoscopic gastric bypass versus laparoscopic adjustable gastric banding for the treatment of morbid obesity: outcomes, quality of life, and costs. Ann Surg 2009; 250: Strain GW, Gagner M, Pomp A, Dakin G, Inabnet WB, Hsieh J et al. Comparison of weight loss and body composition changes with four surgical procedures. Surg Obes Relat Dis 2009; 5: Santry HP, Gillen DL, Lauderdale DS. Trends in bariatric surgical procedures. JAMA 2005; 294: Christou NV, Look D, Maclean LD. Weight gain after short- and long-limb gastric bypass in patients followed for longer than 10 years. Ann Surg 2006; 244: MacLean LD, Rhode BM, Nohr CW. Late outcome of isolated gastric bypass. Ann Surg 2000; 231: Prachand VN, Davee RT, Alverdy JC. Duodenal switch provides superior weight loss in the super-obese (BMI > or = 50 kg/m 2 ) compared with gastric bypass. Ann Surg 2006; 244: Ren CJ, Patterson E, Gagner M. Early results of laparoscopic biliopancreatic diversion with duodenal switch: a case series of 40 consecutive patients. Obes Surg 2000; 10: National Institute for Health and Clinical Excellence (NICE). Obesity: Guidance on the Prevention, Identification, Assessment and Management of Overweight and Obesity in Adults and Children. NICE: London, 2006.

6 84 C. J. Magee, J. Barry, J. Brocklehurst, S. Javed, R. Macadam and D. D. Kerrigan 11 Wolf AM, Falcone AR, Kortner B, Kuhlmann HW. BAROS: an effective system to evaluate the results of patients after bariatric surgery. Obes Surg 2000; 10: Matteotti R, Gagner M. Laparoscopic biliopancreatic diversion with duodenal switch. In Minimally Invasive Bariatric Surgery, PR Schauer, Schirmer BD, Brethauer SA (eds). Springer: New York, 2007; Magee CJ, Barry J, Javed MS, Macadam RC, Kerrigan DD. Extended thromboprophylaxis reduces the incidence of post-operative venous thromboembolism in laparoscopic bariatric surgery. Surg Obes Relat Dis 2020; 6: DeMaria EJ, Portenier D, Wolfe L. Obesity surgery mortality risk score: proposal for a clinically useful score to predict mortality risk in patients undergoing gastric bypass. Surg Obes Relat Dis 2007; 3: Sugerman HJ, Londrey GL, Kellum JM, Wolf L, Liszka T, Engle KM et al. Weight loss with vertical banded gastroplasty and Roux-Y gastric bypass for morbid obesity with selective versus random assignment. Am J Surg 1989; 157: Hess DS, Hess DW. Biliopancreatic diversion with a duodenal switch. Obes Surg 1998; 8: Anthone GJ, Lord RV, DeMeester TR, Crookes PF. The duodenal switch operation for the treatment of morbid obesity. Ann Surg 2003; 238: Marceau P, Hould FS, Simard S, Lebel S, Bourque RA, Potvin M et al. Biliopancreatic diversion with duodenal switch. World J Surg 1998; 22: Scopinaro N, Gianetta E, Adami GF, Friedman D, Traverso E, Marinari GM et al. Biliopancreatic diversion for obesity at eighteen years. Surgery 1996; 119: Rabkin RA. Distal gastric bypass/duodenal switch procedure, Roux-en-Y gastric bypass and biliopancreatic diversion in a community practice. Obes Surg 1998; 8: Carmody BJ, Sugerman HJ, Kellum JM, Jamal MK, Johnson JM, Carbonell AM et al. Pulmonary embolism complicating bariatric surgery: detailed analysis of a single institution s 24-year experience. JAmCollSurg2006; 203: Dolan K, Hatzifotis M, Newbury L, Lowe N, Fielding G. A clinical and nutritional comparison of biliopancreatic diversion with and without duodenal switch. Ann Surg 2004; 240: Saltzman E, Anderson W, Apovian CM, Boulton H, Chamberlain A, Cullum-Dugan D et al. Criteria for patient selection and multidisciplinary evaluation and treatment of the weight loss surgery patient. Obes Res 2005; 13: Slater GH, Ren CJ, Siegel N, Williams T, Barr D, Wolfe B et al. Serum fat-soluble vitamin deficiency and abnormal calcium metabolism after malabsorptive bariatric surgery. J Gastrointest Surg 2004; 8: Commentary Outcome of laparoscopic duodenal switch for morbid obesity (Br J Surg 2011; 98; 79 84) This single-institution series suggests that the indications for duodenal switch can safely be broadened. It is not the first time in the surgical literature on obesity that a new method has been proposed to give better weight reduction in a short-term uncontrolled series. However, so far only one prospective randomized controlled study has compared duodenal switch with gastric bypass 1. The strength of the paper lies in the brilliant surgical results, and in the presentation of complications and side-effects. The authors found a high incidence of severe complications during the early phase of the learning curve. Anyone attempting to start this procedure laparoscopically on superobese patients must therefore be extremely well prepared and properly trained by a team of experienced surgeons in high-volume centres. The pioneers of a new procedure have a special responsibility to present data on either working mechanisms or comparisons with the gold standard in bariatric surgery, focused not only on weight reduction and resolution of co-morbidities but also on the potentially negative effects on gastrointestinal function as well as the nutritional consequences 2. Every morbidly obese patient obviously wants the most effective method. There is a risk that patient demands on bodyweight reduction rather than health benefits and functional normalization will become the main driving force in 2010 British Journal of Surgery Society Ltd British Journal of Surgery 2011; 98: 84 85

7 Laparoscopic duodenal switch for morbid obesity 85 the popularization of this method. More data on long-term follow-up and the potential long-term consequences on gastrointestinal function and problems in macronutrient and micronutrient uptake are needed in order to define the correct place and indications for the duodenal switch procedure. M. Wirén Department of Surgery, Karolinska University Hospital, Stockholm, Sweden ( DOI: /bjs.7308 References 1 Laurenius A, Taha O, Maleckas A, Lönroth H, Olbers T. Laparoscopic biliopancreatic diversion/duodenal switch or laparoscopic Roux-en-Y gastric bypass for super-obesity-weight loss versus side effects. Surg Obes Relat Dis 2010; 6: Aasheim ET, Björkman S, Søvik TT, Engström M, Hanvold SE, Mala T et al. Vitamin status after bariatric surgery: a randomized study of gastric bypass and duodenal switch. Am J Clin Nutr 2009; 90: If you wish to comment on this, or any other article published in the BJS, please visit the on-line correspondence section of the website ( Electronic communications will be reviewed by the Correspondence Editor and a selection will appear in the correspondence section of the Journal. Time taken to produce a thoughtful and well written letter will improve the chances of publication in the Journal British Journal of Surgery Society Ltd British Journal of Surgery 2011; 98: 84 85