Managing obesity and the gastric bypass: understanding anatomy and major postoperative complications

Transcription

1 Managing obesity and the gastric bypass: understanding anatomy and major postoperative complications Poster No.: C-1323 Congress: ECR 2015 Type: Educational Exhibit Authors: S. Tincey, A. N. Tavare, A. Salam, H. Madani, M. Steward; London/UK Keywords: Contrast agent-oral, Contrast agent-intravenous, Fluoroscopy, CT, Abdomen, Eating disorders, Obstruction / Occlusion DOI: /ecr2015/C-1323 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 35

2 Learning objectives Description of the surgical techniques utilised for surgical gastric bypass Understanding the normal radiological anatomy Discussion of the major post-operative complications using multi-modality technique Implications for further management with clinico-radiological correlation Page 2 of 35

3 Background Definition The term obese is derived from the Latin obesus, "to devour". It represents high body fat to lean body mass ratio and is an independent predictor of mortality. Morbid obesity is defined as: BMI of 35 kg/m2 with presence of co-morbidity BMI of 40 kg/m2 regardless of the presence of co-morbidity Prevalence With the known established health risks and sharp increase in prevalence worldwide, obesity has become a major health challenge. About 2.1 billion people representing nearly 30% of the population of the planet are currently overweight or obese according to recent figures. The UK has some of the highest levels of obesity in Western Europe. In the UK, 67% of men and 57% of women are either overweight or obese according to the Global Burden of Disease study 2013, published in the Lancet medical journal. (6) Page 3 of 35

4 Fig. 1: Levels of obesity are rapidly increasing on a global scale. References: Economic impact Urgent attention and leadership is required on a global scale to help countries to intervene more effectively as obesity is fast becoming a major contributor to financial burden for healthcare providers. According to published National Health Service figures, the numbers of patients in England having gastric bypass procedures for obesity has soared by almost 2,000% over a decade; from 242 in to 4,074 in (6) Treating obesity and obesity-related conditions costs billions of dollars a year. By one estimate, the U.S. spent $190 billion on obesity-related health care expenses in (5) More often, physicians are looking towards surgical options in the fight against rising obesity. Procedure background Page 4 of 35

5 There are two main types of bariatric surgery: Restrictive: promotes early satiety by reducing stomach volume, including gastric sleeve, gastric bands, intra-gastric balloon, gastric plication Malabsorptive: reduces caloric intake by altering gastrointestinal physiology eg. small bowel shunt i.e. jejuno-ileal bypass, bilio-pancreatic diversion. A combination of malabsorptive and restrictive techniques is the Roux-en-Y gastric bypass, which is currently the most popular bariatric procedure performed in the USA. It is associated with a greater sustained weight loss and higher long-term success rates than other forms of bariatric surgery. For the purposes of this poster, we will now focus on the anatomy and postoperative complications of Roux-en-Y bypass in greater detail using illustrated radiological examples. Page 5 of 35

6 Images for this section: Fig. 1: Levels of obesity are rapidly increasing on a global scale. Page 6 of 35

7 Findings and procedure details Surgical technique for Roux-en-Y bypass A small gastric pouch is created using a staple cutter device in order to restrict food intake. The pouch volume is approximately ml. The stomach is compartmentalised into a small fundal component (ie, gastric pouch) and a much larger excluded component. The jejunum is then divided cm distal to the ligament of Treitz, and the distal limb (ie, the Roux limb, efferent or alimentary limb) is brought up and anastomosed to the gastric pouch using an end-to-end or end-to-side gastrojejunal anastomosis, creating a blind-ending jejunal stump. (3) Page 7 of 35

8 Fig. 2: Diagram outlining anatomy of Roux-en-Y gastric bypass. References: 2014 University of Nebraska Medical Center A deliberately small-calibre stoma, with the gastrojejunal anastomosis, is used to limit emptying of solid food from the gastric pouch and facilitate weight loss by means of a restrictive effect and reduced caloric absorption (2). Finally, the proximal limb of the divided jejunum (ie, the afferent or biliopancreatic limb) is anastomosed to the small bowel distal to the gastrojejunostomy to create a common Page 8 of 35

9 channel that continues into the ileum. The jejunojejunostomy is usually created by means of a side-to-side anastomosis to decrease the risk of stricture formation (3). Fig. 3: Diagram outlining surgical technique and anatomy after Roux-en-Y bypass. References: 2015 UpToDate Occasionally, a cholecystectomy is performed simultaneously to avoid the gallstones that may result from rapid weight loss. Page 9 of 35

10 Normal imaging findings Upper GI Fluoroscopy With Roux-en-Y bypass, it is important to evaluate the gastrojejunostomy and jejunojejunostomy sites for leakage or stricture. Fig. 4: Normal Upper GI Fluoroscopic image demonstrating contrast filled gastric fundus. Page 10 of 35

11 References: Radiology Department, Royal Free Hospital, Royal Free Hospital London/UK Contrast: A water soluble contrast agent is ingested first to rule out frank leakage of contrast. If unclear, barium may be utilised to better opacify a region of interest on confirmation of no leak. Patient positioning: The patient should stand with their back against the fluoroscopy table with contrast in their left hand, away from the abdomen and image intensifier. Once water-soluble contrast has been administered, views of the gastrojejunal anastomosis should be taken in a supine or supine left posterior oblique position as leaks will appear as blind-ending tracts abutting the anastomotic region or as free leaks into the peritoneal cavity. Scout image: Image the operative bed to visualise areas of increased opacity that may mimic leak. Page 11 of 35

12 Fig. 5: Fluoroscopy image diagram of Roux-en-Y bypass:- Creation of a gastric pouch (green) with the excluded gastric remnant (red) left in place. The mid jejunum (blue) is anastomosed with the gastric pouch (green) becoming the efferent Roux limb (blue), continuing to the distal gastrointestinal tract. The proximal jejunum (orange) is anastomosed with the efferent Roux limb (blue) with the proximal jejunum (orange) and excluded gastric remnant (red) becoming the afferent biliopancreatic limb (orange). References: Radiology Department, Royal Free Hospital, Royal Free Hospital London/UK If a nasogastric tube crosses the gastrojejunal anastomosis, it should be pulled back prior to fluoroscopic evaluation as its presence may obscure or prevent detection of an underlying leak. Page 12 of 35

13 Abdominal CT CT studies are performed with both oral and intravenous contrast agents. Identification of the gastric pouch, gastrojejunal anastomosis, jejunal Roux limb, jejunojejunal anastomosis, and excluded biliopancreatic limb on CT scans is essential for detecting potential complications such as internal hernias and small bowel obstructions. (2) Postoperative complications in Roux-en-Y bypass Post operatively, these patients are evaluated with fluoroscopic and CT studies to assess for early or late complications at the GJ and JJ anastamotic sites. Symptoms including reflux symptoms, epigastric pain, abdominal pain, heartburn are common in this period and should be investigated to rule out complications. Table1. Complications and incidence of Roux-en-Y bypass (4) Complication Incidence Presentation Findings on CT Anasatomotic leak 2-5% Early Contrast extravasation Air-fluid level adjacent to the site of leakage Air and contrast material tracking along drain Wound infection Up to 10% Early Gas locules and stranding at wound site Possible abscess formation Anastomotic stricture 3-9% Late > Early Possible gastric pouch dilatation Page 13 of 35

14 Possible oesophageal reflux of contrast Normal small bowel calibre distal to anastomosis Small obstruction bowel 1-5 % Late > Early Dilated cluster of small bowel loops Intussusception with a target sign appearance Anastomotic staple % disruption Late > Early Dense contrast material and air in gastric remnant Hernia (incisional 6-17 % and internal) Late Engorgement or swirling of mesenteric vessels Possible closed loop small bowel obstruction Marginal ulcer % Late Endoscopy superior to CT in diagnosis Anastomotic leak An extraluminal leak is the most serious early complication of Roux-en-Y gastric bypass occurring in up to 5% of patients. Up to 70% of leaks involve the gastrojejunal anastomosis, but other less common sites of perforation include the gastric pouch, blindending jejunal stump, and jejunojejunal anastomosis. Leaks require early detection due to the risk of abscess formation, peritonitis and patients present with signs of sepsis (1). including fever, pain, and tachycardia Page 14 of 35

15 Fig. 6: Axial CT study showing a contrast leak with gas containing collection. References: Radiology Department, Whittington Hospital, London UK During upper GI examinations a scout image can be used to detect loculated or free extraluminal gas as well as radiopaque staple lines that otherwise could be mistaken for small leaks during the fluoroscopic examination. Once water-soluble contrast material has been administered, most leaks from the gastrojejunal anastomosis are best visualised with the patient in a supine or supine left posterior oblique position, appearing as blind-ending tracks or sealed-off collections. Fistulous connections can also be assessed. Page 15 of 35

16 Fig. 8: Fluoroscopy image showing contrast in the alimentary limb (running vertically) but also in gastric remnant (arrow) implying a fistulous connection. References: Radiology Department, Whittington Hospital, London UK Leaks will usually require repeat surgical intervention however small contained leaks may be treated with percutaneous drainage and antibiotics. Anastomotic strictures Page 16 of 35

17 Transient anastomotic narrowing may occur during the early postoperative period secondary to residual postoperative oedema in this region and this usually resolves within several days. Upper GI examinations may reveal focal narrowing of the anastomosis with thickened, irregular folds in the Roux limb abutting the anastomosis (3). Anastomotic strictures usually occur at a later stage, up to 4 weeks post surgery, presenting with postprandial vomiting, bloating, and upper abdominal pain. Strictures appear on upper GI studies as short segments of smooth narrowing at the gastrojejunal anastomositic site. If obstructed, the gastric pouch may be dilated with delayed emptying of contrast into the Roux limb. Treatment is via endoscopic dilation of the strictures and patients generally demonstrate a good response, however some patients may require multiple dilation procedures. Marginal ulcers These usually occur at a later stage as solitary ulcers of varying size. Patients present with symptoms of dyspepsia and upper GI bleeding. Radiographic diagnosis remains difficult and despite evidence of ulceration on endoscopy, upper GI imaging and CT may often be negative. Most marginal ulcers respond to medical therapy with anti-secretory agents i.e., proton pump inhibitors. (1) Small bowel obstruction Obstructions are more frequently encountered after laparoscopic bypass than with open procedures. They may occur anywhere and have varied radiographic appearances. Early obstruction is often due to oedema or haematoma at the GJ anastomosis, transverse mesocolon, and JJ anastomosis. Late obstruction may be due to internal hernia, less commonly adhesions and rarely intussusception. Intussusception may be seen on CT as a classic target sign with possible obstruction of the proximal small bowel or gastric pouch. It is important to identify the level of obstruction Dilated Roux limb Dilated excluded biliopancreatic limb Dilated Roux and excluded biliopancreatic limbs Page 17 of 35

18 Internal hernia Internal hernias may occur due to the herniation of small bowel loops through a defect in the transverse mesocolon, small bowel mesentery, or through a potential space posterior to the Roux limb (the Petersen space). Signs include clustering of small bowel loops compressed against the anterior abdominal wall with crowding. (3) Fig. 7: Axial CT image of a surgically proven internal hernia with upstream small bowel dilatation and a right sided entero-enteric anastamosis (see arrow). References: Radiology Department, Whittington Hospital, London UK There may be engorgement of mesenteric vessels seen on contrast enhanced CT with abrupt mesenteric twisting producing loacalised oedema secondary to lymphatic and venous obstruction. (1) Page 18 of 35

19 Fig. 9: Axial MDCT of a surgically proven internal hernia demonstrating CT sign of mesenteric swirling (see arrow). References: Radiology Department, Whittington Hospital, London UK Page 19 of 35

20 Fig. 10: Coronal CT image showing mesenteric swirling (arrow) in a surgically proven internal hernia. References: Radiology Department, Whittington Hospital, London UK Page 20 of 35

21 Fig. 11: Axial CT showing mesenteric swirling with mesenteric engorgement (arrow) in an internal hernia proven surgically. References: Radiology Department, Whittington Hospital, London UK Small bowel loops have the potential to become incarcerated which can lead to obstruction, infarction, and perforation of strangulated loops. Hence, delays in diagnosis of internal hernias can be devastating and a high index of suspicion is required since the clinical findings are generally non-specific. (3) Surgical expoloration should be considered. Wound infection and abscess Abscess formation may be secondary to intestinal perforation. These patients will present with pain and generalised signs of sepsis. CT studies are useful in demonstrating fluid collections often with rim enhancement containing both gas and fluid. Wound complication may be demonstrated on CT by mild fat stranding or locules of gas in closed trocar defects. (1) Page 21 of 35

22 Dependant on the size and location of the infective collection, percutaneous drainage may be used alongside appropriate antibiotic therapy. Page 22 of 35

23 Images for this section: Fig. 2: Diagram outlining anatomy of Roux-en-Y gastric bypass University of Nebraska Medical Center Page 23 of 35

24 Fig. 3: Diagram outlining surgical technique and anatomy after Roux-en-Y bypass UpToDate Page 24 of 35

25 Fig. 4: Normal Upper GI Fluoroscopic image demonstrating contrast filled gastric fundus. Radiology Department, Royal Free Hospital, Royal Free Hospital - London/UK Page 25 of 35

26 Fig. 5: Fluoroscopy image diagram of Roux-en-Y bypass:- Creation of a gastric pouch (green) with the excluded gastric remnant (red) left in place. The mid jejunum (blue) is anastomosed with the gastric pouch (green) becoming the efferent Roux limb (blue), continuing to the distal gastrointestinal tract. The proximal jejunum (orange) is anastomosed with the efferent Roux limb (blue) with the proximal jejunum (orange) and excluded gastric remnant (red) becoming the afferent biliopancreatic limb (orange). Radiology Department, Royal Free Hospital, Royal Free Hospital - London/UK Page 26 of 35

27 Fig. 6: Axial CT study showing a contrast leak with gas containing collection. Radiology Department, Whittington Hospital, London UK Page 27 of 35

28 Fig. 7: Axial CT image of a surgically proven internal hernia with upstream small bowel dilatation and a right sided entero-enteric anastamosis (see arrow). Radiology Department, Whittington Hospital, London UK Page 28 of 35

29 Fig. 8: Fluoroscopy image showing contrast in the alimentary limb (running vertically) but also in gastric remnant (arrow) implying a fistulous connection. Radiology Department, Whittington Hospital, London UK Page 29 of 35

30 Fig. 9: Axial MDCT of a surgically proven internal hernia demonstrating CT sign of mesenteric swirling (see arrow). Radiology Department, Whittington Hospital, London UK Page 30 of 35

31 Fig. 10: Coronal CT image showing mesenteric swirling (arrow) in a surgically proven internal hernia. Radiology Department, Whittington Hospital, London UK Page 31 of 35

32 Fig. 11: Axial CT showing mesenteric swirling with mesenteric engorgement (arrow) in an internal hernia proven surgically. Radiology Department, Whittington Hospital, London UK Page 32 of 35

33 Conclusion Obesity is a growing global problem affecting patients of all ages. As a major contributor to mortality and morbidity rates it casts a huge economic burden on healthcare providers with significant implications for international health and social care. The enormity of this economic burden and the impact that excess weight has on health and well-being are beginning to raise international awareness that individuals and organisations must do more to combat obesity. (5) As the number of bariatric operations continues to rise, a basic knowledge of the surgical procedures is of vital importance to a radiologist for evaluation of potential complications in the early and late postoperative period. Page 33 of 35

34 Personal information Page 34 of 35

35 References Radiology of the laparoscopic Roux-en-Y gastric bypass procedure: Conceptualisation and precise interpretation of results. Scheirey C, et al. Radiographics 2006; 26: Normal anatomy and complications after gastric bypass surgery: Helical CT findings. Jinxing Y, Turner M, et al. Radiology 2004; 231: Imaging of bariatric surgery: normal anatomy and postoperative complications. Levine M, Carucci R. Radiology Feb; 270(2): Imaging in bariatric surgery: A guide to postsurgical anatomy and common complications. Chandler R. Gujjarrapa S, et al. AJR 2008;19; Harvard School of Public Health Obesity Prevention Source Web site: economic/ Global, regional, and national prevalence of overweight and obesity in children and adults during : a systematic analysis for the Global Burden of Disease Study Ng M, Flemming T, et al. The Lancet 2014.Volume 384; 9945: Page 35 of 35