The essential bariatric surgery primer: what all radiologists need to know

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1 The essential bariatric surgery primer: what all radiologists need to know Poster No.: C-2371 Congress: ECR 2013 Type: Educational Exhibit Authors: H. Lambie, K. Harris, J. BRITTENDEN, D. Tolan ; Leeds/UK, Bishopthorpe York, no/uk Keywords: Surgery, Barium meal, Fluoroscopy, CT, Stomach (incl. Esophagus), Gastrointestinal tract, Abdomen, Abscess DOI: /ecr2013/C-2371 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 58

2 Learning objectives To outline the common bariatric procedures performed. To demonstrate normal post-operative anatomy and imaging. To illustrate the potential complications of each procedure. Background Obesity is increasing across Europe. Bariatric surgery is an effective way for patients to achieve sustainable weight loss. It has been shown to reduce overall mortality in obese patients and is associated with beneficial effects on diabetes and cardiovascular disease (1). Bariatric procedures have evolved over the past 50 years. They are based on procedures that create malabsorption, restrict volume intake or a combination of both (2). The common bariatric procedures performed include Laparoscopic adjustable gastric band (LAGB), Sleeve gastrectomy and Roux-en-Y gastric bypass. Radiologists are required to understand the surgical procedures performed to allow interpretation of postoperative imaging, recognise complications and in some instances, treat complications. An awareness of the less common procedures and historical procedures is also beneficial, as patients who have undergone these procedures in the past may present for abdominal imaging for unrelated symptoms. We illustrate the post-operative anatomy of each of these procedures. Patients undergoing bariatric procedures may suffer from general complications related to obesity in addition to complications specific to each procedure. The imaging features of these complications are reviewed. Radiologists may also be involved in the management of complications, for example draining post-operative collections under CT guidance. Imaging findings OR Procedure details General considerations for imaging post bariatric surgery Page 2 of 58

3 Weight limit/size of equipment Both the weight of the patient and the patient's girth may preclude fluoroscopic and CT examinations in very obese patients. In fluoroscopy the footrest may be removed from the table to allow the patient to stand on the floor if the patient exceeds the weight limit of the table. Serial abdominal radiographs post oral contrast are an alternative to fluoroscopy and CT if the patients girth precludes access to the CT gantry or fluoroscopy aperture. Tube limit Beam attenuation by obese patients can cause tube overloading. Using a larger field of view and single exposures rather than exposure "runs" (e.g. 2 frames/s) can avoid this. Post-operative complications Surgery in obese patients is often technically challenging and the rate of post-operative complications is higher in obese patients. The size of the patient may make radiological management of post-operative complications (e.g. length or needles for percutaneous drainage and patient positioning for stent placements) more challenging. Laparoscopic adjustable gastric band (LAGB) Surgical procedure: The laparoscopic adjustable gastric band is an inflatable synthetic band placed just below the gastro-oesophageal junction. A form of restrictive surgery, a small gastric pouch forms over time above the band. Restriction produces early satiety and reduced calorific intake. The band is connected by tubing to a port that is placed subcutaneously in the anterior abdominal wall at surgery. This port allows adjustments to be made to the band via an atraumatic needle (e.g. Huber needle). This is usually done in the surgical out-patient clinic as required. A minority of patients have adjustments performed in the radiology department (usually when the surgeon cannot feel the port to puncture it). Page 3 of 58

4 Fig. 1: Laparoscopic Adjustable Gastric Band. The inflatable gastric band is positioned just below the gastro-oesophageal junction to create a small gastric pouch just above it. The band is connected to a subcutaneous port that can be used for adjustments. References: - Leeds/UK Normal post operative imaging: The band should be just below the oesophageal hiatus at approximately a 45 angle to the horizontal. There should be an unbroken line of tubing connecting the band to the port, which is seen as a circular structure. Page 4 of 58

5 Fig. 2: An example of a well placed gastric band. Note the band lies at an angle of 45 degrees to the horizontal just below the hiatus, the port is seen as a circle and the tubing connecting them is intact. References: - Leeds/UK Knowledge of the normal appearances of a variety of different types of gastric bands is required. They also vary in the volume required to inflate the band to capacity. Page 5 of 58

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7 Fig. 3: Another example of a well placed gastric band. This port has four swirled fixation anchors. The "tail" of the horizontally positioned loops point anticlockwise when correctly orientated. If the port flips over the horizontally placed loops lie so that the "tail" of the loops point clockwise. References: - Leeds/UK When performing a barium swallow, a control radiograph should be performed to assess the orientation of the band. If there is adequate restriction, a small pouch should form above the band during transit of contrast. The band channel should measure 3-4 mm in diameter and allow contrast to pass through the band with no signs of dysmotility (3). Page 7 of 58

8 Fig. 4: Normal post-operative imaging of a LAGB. A small focal gastric pouch has formed above the band from dilatation of the gastro-oesophageal junction due to restriction. References: Brittenden J, Tolan JMT eds. Radiology of the Post Surgical Abdomen. Springer 2012 Page 8 of 58

9 Post-operative complications: Band too tight On fluoroscopy there is dilatation of the oesophagus rather than a small gastric pouch and signs of dysmotility (tertiary contractions rather than a strong primary stripping wave). Chronic over restriction can result in irreversible atony of the oesophagus. Page 9 of 58

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11 Fig. 5: Over restriction of a gastric band with stasis of contrast in the oesophagus and tertiary contractions (arrowhead) indicating oesophageal dysmotility. References: Brittenden J, Tolan JMT eds. Radiology of the Post Surgical Abdomen. Springer 2012 Band too loose This is one of the causes of weight gain post surgery. Contrast passes freely through the gastric band without the formation of a gastric pouch/proximal dilatation. Band migration The band moves inferiorly from the gastro-oesophageal junction. This may be visible on a plain abdominal x-ray with the band assuming a more horizontal or vertical position then usual. The gastric fundus and body become incorporated with the pouch, which dilates eccentrically. This requires revision surgery in all cases. Page 11 of 58

12 Fig. 6: Slipped gastric band. Note the horizontal orientation of the gastric band and the large eccentric gastric pouch that has formed above it. References: - Leeds/UK Band erosion The gastric band erodes through the gastric wall in to the stomach, usually over several months. On fluoroscopy an intraluminal band segment or oral contrast/bowel gas peripheral to the band may be seen (3). This requires revision surgery in all cases. Page 12 of 58

13 Fig. 7: Gastric band erosion. The gastric band now lies in the gastric lumen and contrast can be seen outlining outside the band (arrow). References: - Leeds/UK Open band If the band in incompletely fixed at surgery it can open, producing a "C" or "U" shape on imaging with no restriction (4). This requires revision surgery in all cases. Page 13 of 58

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15 Fig. 8: Open band. The ring configuration of the gastric band is disrupted and it has assumed an open U shape. References: Brittenden J, Tolan JMT eds. Radiology of the Post Surgical Abdomen. Springer 2012 Food impaction Food impaction can occur even in optimally filled gastric bands, frequently requiring endoscopic removal of the bolus. A filling defect is seen on fluoroscopy just proximal to the gastric band. Fig. 9: Food bolus impaction. A food bolus is seen as a filling defect just proximal to the gastric band on barium swallow with barium pooling proximally. References: - Leeds/UK Page 15 of 58

16 Tube fracture or disconnection This results in lack of restriction as the fluid filling the gastric band leaks out. It is demonstrated on imaging as a discontinuity in the tubing connecting the band to the port. This requires revision surgery in all cases, which is usually quite straight forward. Page 16 of 58

17 Fig. 10: Tube fracture. The tube connecting the gastric band and post has fractured (arrow). References: Brittenden J, Tolan JMT eds. Radiology of the Post Surgical Abdomen. Springer 2012 Page 17 of 58

18 A potential pitfall: If gas is present in the tubing, it can mimic tube fracture. Page 18 of 58

19 Fig. 11: Gas in the tubing can mimic tube fracture. On careful inspection there is a lucent line (the tube containing gas) in the expected position of the tube. References: - Leeds/UK Port rotation The port can rotate so that the membrane for puncture is no longer facing anteriorly. On imaging the port may assume an oval or linear configuration instead of its en-face circular appearance (4). Port site infection The subcutaneous port site can become infected. This may be apparent clinically or demonstrated as fat stranding around the port, tube or band on CT (5). Roux-en-Y Gastric bypass (RYGB) Roux-en-Y gastric bypass is the commonest bariatric procedure performed. It combines a restrictive effect, by the creation of a small (15-30ml) gastric pouch from the proximal stomach and a malabsorptive effect by bringing up a Roux loop and anastomosing it (usually with a side-side anastomosis) to the gastric pouch (6). The Roux loop may be placed in an antecolic position or through the transverse mesocolon in a retrocolic position. A jejunojejunostomy is created approximately cm distal from the gastrojejunostomy - bypassing a segment of small bowel gives the patient less ability to absorb nutrients, which helps with weight loss. Any visible defects in the mesentery are closed at surgery. Page 19 of 58

20 Fig. 12: Roux-en-Y gastric bypass References: - Leeds/UK Normal post-operative imaging: Water-soluble swallow may be performed post surgery to assess integrity of the gastric pouch and gastrojejunostomy. A frontal control radiograph should be performed to demonstrate the staple lines. Contrast should flow freely through the small gastric pouch and gastrojejunostomy into the roux loop. There may be a small blind ending limb created by the side to side anastomosis. Page 20 of 58

21 Fig. 13: Normal gastric pouch and gastro-jejunal anastomosis post RYGB. The white arrow indicates the direction of the roux-loop towards the distal entero-enteric anastomosis. References: - Leeds/UK Post-operative complications: Anastomotic leak Page 21 of 58

22 The commonest site of leak is from the gastrojejunostomy. On fluoroscopy, contrast is seen outside the gastric pouch and anastomosis. These may heal by resting the bowel and feeding the patient distal to the leak with nasojejunal or jejunostomy feeding. A potential pitfall on fluoroscopy: The blind end of the Roux loop can sometime be quite long and should not be misinterpreted as a contained leak. A potential pitfall on CT: The excluded stomach lies adjacent to the gastric pouch, separated from it by a staple line. It is frequently fluid filled and should not be mistaken for a collection. Page 22 of 58

23 Fig. 14: CT image showing a small left upper quadrant collection (c) following a leak from the gastojejunostomy. The excluded stomach (s) should not be mistaken for a collection, since it abuts the staple line and gastric pouch (gp). References: Brittenden J, Tolan JMT eds. Radiology of the Post Surgical Abdomen. Springer 2012 Leaks are much less common from the distal jejunojejunal anastomosis and are difficult to detect on water-soluble contrast studies due to dilution of contrast (4). Page 23 of 58

24 Fig. 15: Leak from the distal jejunojejunal anastomosis post RYGB, with gross spillage of contrast into the peritoneum (arrows). References: Brittenden J, Tolan JMT eds. Radiology of the Post Surgical Abdomen. Springer 2012 Anastomotic stricture Anastomotic strictures usually occur at the gastrojejunostomy and are rare at the jejunojejunostomy. In the early post-operative period strictures are usually caused by oedema and resolve on later fluoroscopic examinations. However strictures can also be caused by ischaemia and adhesions. Imaging appearances are of narrowing of the gastrojejunal anastomosis and enlargement of the gastric pouch. Page 24 of 58

25 Fig. 16: Gastrojejunal stricture post RYGB. Note the tight narrowing (stricture) of the gastrojejunal anastomosis and the rounded appearance of the gastric pouch. References: - Leeds/UK Fistula to the excluded stomach If disruption of the gastric staple line occurs, a fistula may develop between the gastric pouch and the excluded stomach. This may occur due to mechanical failure of staples in the early post-operative period or patients can present years post surgery with weight gain Page 25 of 58

26 or pain. On fluoroscopy contrast flows from the gastric pouch to the excluded stomach and is seen in the remnant stomach and pancreaticobiliary limb. By turning the patient obliquely it may be possible to demonstrate the fistula. Page 26 of 58

27 Fig. 17: A fistula (F) has formed between the gastric pouch and excluded stomach with preferential passage of contrast through the stomach and pancreaticobiliary limb rather than the through the gastrojejunal anastomosis. Page 27 of 58

28 References: Brittenden J, Tolan JMT eds. Radiology of the Post Surgical Abdomen. Springer 2012 Fig. 18: Same patient as Fig 12 demonstrating the preferential passage of contrast through the pancreaticobiliary limb. References: Brittenden J, Tolan JMT eds. Radiology of the Post Surgical Abdomen. Springer 2012 Internal hernia Page 28 of 58

29 Internal hernias typically occur at three sites: 1. Through the transverse mesocolon (in patients with retrocolic placement of the Roux loop). 2. Through a defect in the small bowel mesentery at the jejunojejunostomy. 3. Behind the Roux loop (Petersen hernia). On fluoroscopy the Roux loop is dilated - however it may be difficult to see the transition point. On CT the findings include a cluster of small bowel loops of the left side of the abdomen, multiple loops of small bowel above the transverse mesocolon (in mesocolic herniation), a swirl of engorged mesenteric vessels and "pinching" of the dilated roux loop as it passes through the mesenteric defect (4). Remember that obstruction of the biliopancreatic limb can cause dilatation of the excluded stomach - this is abnormal! Page 29 of 58

30 Fig. 19: A coronal image from a CT demonstrating obstruction of both the roux loop and the pancreaticobiliary limb. An abrupt cut-off point is seen centrally within the abdomen (*) and an internal hernia through a defect in the small bowel mesentery was confirmed at surgery. References: - Leeds/UK Other causes of obstruction Other causes of obstruction include laparoscopic port site hernias and adhesional obstruction. Page 30 of 58

31 Fig. 20: CT performed for recurrent vomiting post Laparoscopic RYGB shows dilated small bowel loops with an abrupt transition point at a port site hernia in the left anterior abdominal wall (white arrow) and a collapsed distal small bowel loop (black arrow). References: Brittenden J, Tolan JMT eds. Radiology of the Post Surgical Abdomen. Springer 2012 Infection Obese patients have an increased risk of post-operative infections particularly wound infections. Incisional hernias may develop and if repaired with mesh this is another potential site of infection. Page 31 of 58

32 Fig. 21: CT image showing a superficial anterior abdominal collection (white arrows) in a patient who has undergone a mesh hernia repair (note the mesh clips - orange arrows) for an incisional hernia post RYGB. References: - Leeds/UK Malnutrition Malnutrition is a significant risk associated with bariatric procedures, particularly those like RYGB with a malabsorptive effect. The major nutritional deficiency after bariatric surgery is protein malnutrition, however deficiencies in trace elements, essential minerals, and water-soluble and fat-soluble vitamins are also seen. Protein malnutrition leads to steatosis seen on CT as a "fatty liver" (7). Page 32 of 58

33 Fig. 22: CT image showing diffuse fatty infiltration of the liver (L) secondary to protein malnutrition. Note the suture line (arrow) separating the gastric pouch from the excluded stomach from the previous RYGB. References: - Leeds/UK Sleeve Gastrectomy Surgical procedure: A gastric tube "sleeve" of reduced capacity (approximately 100 ml) is created along the lesser curve by stapling along the length of the stomach. A bougie tube is used at surgery Page 33 of 58

34 to calibrate the size of the gastric sleeve. The excluded fundus and greater curvature are removed. This reduces the size of the stomach by about 75% and produces a restrictive effect (8). Fig. 23: Sleeve gastrectomy. A vertical staple line resects the fundus and greater curve of the stomach creating a narrow gastric tube or sleeve. References: - Leeds/UK Normal post operative imaging: On post-operative contrast studies a slender gastric tube is seen. Contrast usually passes through freely in to the duodenum, although occasionally in the early postoperative period Page 34 of 58

35 there can be hold up of contrast in the proximal sleeve, thought to be due to antral malfunction (8). Fig. 24: A contrast examination demonstrating a normal slender gastric tube following a sleeve gastrectomy. References: Brittenden J, Tolan JMT eds. Radiology of the Post Surgical Abdomen. Springer 2012 Post-operative complications: Page 35 of 58

36 Gastric dilatation Gastric dilatation is seen as increased diameter of the sleeve with loss of the normal tubular appearance. Patients present with inadequate weight loss or weight gain and 4.5% of patients undergoing sleeve gastrectomy require further surgery for this reason (8). Gastric Leak Gastric leaks post sleeve gastrectomy most commonly occur from the proximal end of the gastric staple line, close to the gastrooesophageal junction, although leaks can occur at any point along the length of the staple line. Page 36 of 58

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38 Fig. 25: Contrast swallow shortly after sleeve gastrectomy with a nasojejunal tube in situ. A leak from the proximal end of the gastric tube is demonstrated. References: - Leeds/UK Gastric tube stricture Strictures can occur at any point along the gastric tube, but are most common at the incisura due to intra-operative stapling (8). Page 38 of 58

39 Fig. 26: A mid-gastric stricture (white arrow) 4 years post sleeve gastrectomy with formation of a proximal pouch (P). This was unresponsive to endoscopic dilation but sustained dilatation was achieved by temporary placement of a retrievable stent (not shown). References: Brittenden J, Tolan JMT eds. Radiology of the Post Surgical Abdomen. Springer 2012 Less commonly performed procedures: Radiologists should be aware of procedures that are either performed uncommonly or those that are no longer performed, since these patients still present for imaging and the normal post operative appearances and complications of these should be understood. Magenstrasse and Mill Procedure (M&M) This is an older procedure that is no longer frequently performed since the advent of the newer techniques described above. The "Magenstrasse" (or street of the stomach) is a narrow gastric tube created from the lesser curvature by stapling from the antrum up to the fundus. Although the fundus and greater curve remain in situ, they are functionally excluded. The Magenstrasse conveys food from the esophagus to the antral "Mill". Gastric juices can exit the excluded stomach into the small common distal antrum (4). Page 39 of 58

40 Fig. 27: Magenstrasse and Mill. A "Magenstrasse" (street of the stomach) is the narrow gastric tube created by stapling from the antrum to the fundus. This conveys food to the antral "Mill". Gastric juices can exit the excluded stomach into the small common distal antrum. References: - Leeds/UK Normal post operative imaging: On fluoroscopy a slender gastric tube is seen emptying into the common antrum. If the procedure is performed supine, contrast may reflux into the excluded stomach from the antrum. Page 40 of 58

41 Fig. 28: Normal post operative appearances of a Magenstrasse and Mill procedure. Contrast passes down the narrow gastric tube to the common antrum with a small amount of contrast refluxing into the "excluded" stomach. References: - Leeds/UK Post-operative complications: Magenstrasse dilatation The Magenstrasse may dilate over time, removing the restriction and resulting in weight gain (4). Fistula to the excluded stomach Page 41 of 58

42 A fistula may develop between the Magenstrasse and the excluded stomach due to staple line dehiscence. On barium swallow there is early filling of the excluded stomach prior to filling of the antrum. Oblique views may help to delineate the fistula. Fig. 29: A fistula (F) has formed between the Magenstrasse gastric tube and the excluded gastric fundus, with contrast filling both the Magenstrasse and the excluded stomach. References: - Leeds/UK Stricture Page 42 of 58

43 A stricture in the Magenstrasse is demonstrated by a tight channel, with dilatation of the gastric tube proximal to the narrowing. Page 43 of 58

44 Fig. 30: A tight stricture has formed in the Magenstrasse with significant proximal dilatation. Page 44 of 58

45 References: - Leeds/UK Vertical Banded Gastroplasty (VBG) Similar to the Magenstrasse and Mill procedure, the vertical banded gastroplasty is another purely restrictive procedure that has been superseded by newer techniques. Like the M&M a vertical staple line partitions the stomach to create a small gastric pouch on the lesser curve. A circular window is made the distal end of the staple line and a synthetic band or mesh is wrapped around the distal end of the gastric pouch producing a stoma into the remainder of the stomach (8). Page 45 of 58

46 Fig. 31: Vertical Banded Gastroplasty (VBG). This is similar to the Magenstrasse and Mill procedure, but in addition a synthetic band is placed around the gastric tube to augment restriction. References: - Leeds/UK Normal post operative imaging: On barium swallow a small gastric pouch is seen, with contrast passing through a narrow stoma (the band) into the remainder of the stomach. Post-operative complications: Stomal narrowing/stenosis Like RYGB, stomal narrowing is usually due to oedema in the immediate post-operative period, which often settles spontaneously. Fluoroscopy demonstrates narrowing of the gastric stoma, delayed outflow from the gastric pouch, and varying degrees of pouch dilatation and gastro-oesophageal reflux. Late stomal stenosis may respond to balloon dilatation (9). Page 46 of 58

47 Fig. 37: Recurrent vomiting 10 years after VBG. The band is causing over restriction and gross dilatation of the pouch (*). The band had eroded into the gastric wall requiring partial gastrectomy and RYGB reconstruction. References: Brittenden J, Tolan JMT eds. Radiology of the Post Surgical Abdomen. Springer 2012 Gastric leak Leaks can occur from either the vertical or circular staple lines. Fistula to the excluded stomach Resulting from disruption of the staple line. On fluoroscopy contrast flows in the direction of least resistance, usually through the fistula into the excluded fundus rather than through the stoma. Page 47 of 58

48 Fig. 32: Disruption of the suture line superiorly with a fistula (F) forming between the gastric pouch and the excluded gastric fundus. References: Brittenden J, Tolan JMT eds. Radiology of the Post Surgical Abdomen. Springer 2012 Pouch enlargement Page 48 of 58

49 The lesser curvature is used to create the pouch because it is thicker and less resistant to stretching than the greater curvature, however pouch enlargement can occur overtime and limit weight loss (9). Food impaction This typically occurs when patients do not adhere to strict dietary measures. Patients with stomal stenosis are at increased risk, but it can occur with normal stomal diameter (9). Duodenal Switch with Biliopancreatic Diversion The duodenal switch is usually performed in conjunction with a sleeve gastrectomy to produce both a restrictive and a malabsorptive affect. Following the sleeve gastrectomy, the duodenum is resected and the distal small bowel anastomosed onto the disconnected duodenum. The remainder of the small bowel is reanastomosed distally. This produces a 150cm Roux limb and a 100cm common channel (shorter than in RYGB) (3). This is usually reserved only for superobese patients and is performed in a very limited number of centres. Page 49 of 58

50 Fig. 33: Duodenal Switch with Biliopancreatic Diversion. The duodenum is divided and the distal small bowel anastomosed to the proximal duodenum. The divided pancreaticobiliary limb is then reanastomosed distally. This procedure is often combined with a sleeve gastrectomy to add a restrictive component to the largely malabsorptive procedure. References: - Leeds/UK Normal post operative imaging: Fluoroscopic examinations demonstrate a slender gastric tube, with contrast flowing through the duodenoenteric anastomosis into the Roux loop. Post-operative complications: Post-operative complications for duodenal switch are similar to those for RYGB, but occur with increased frequency. Anastomotic leak Page 50 of 58

51 Anastomotic leaks may occur at the gastric staple line, the duodenal stump, the duodenoenteric anastomosis or the ileoileostomy. The duodenoenteric anastomosis fashioned in a duodenal switch has a lower leak rate than the gastrojejunostomy formed in RYGB due to reduced tension in the duodenoenteric anastomosis (3). Anastomotic strictures As in RYBG anastomotic strictures are more common at the proximal anastomosis and can be demonstrated on fluoroscopy. Internal hernia Internal hernias occur through the small bowel mesentery into Peterson's space. Mesocolic herniation does not occur as no transverse mesocolon defect is made (3). Combined procedures If inadequate weight loss is obtained following primary bariatric surgery or if there is a complication such as gastric pouch dilatation the surgeon may consider a second procedure. For example a gastric band may be used for a dilated gastric pouch when there is loss of restriction post RYGB. Page 51 of 58

52 Fig. 34: Control film prior to a barium swallow to assess gastric band placement. Note that the gastric band is in a horizontal position which would suggest band migration post a primary gastric band procedure. However there are staple lines evident - the Page 52 of 58

53 patient has had a previous RYGB and the stent has been placed over the residual gastric pouch to improve the restrictive effect. References: - Leeds/UK Page 53 of 58

54 Fig. 35: Barium swallow on same patient as fig 37 demonstrating the gastric band providing a restrictive effect on the gastric pouch from the previous RYGB. Page 54 of 58

55 References: - Leeds/UK Radiologists Treating Complications Radiologists are increasingly asked to treat post-operative complications in a minimally invasive way to avoid revisional surgery. The procedures commonly requested include: Laparoscopic gastric band adjustment The port site for LGB is placed subcutaneously and is usually palpable allowing adjustments to the fluid content and the restrictive effect to be made in the surgical outpatient clinic. However if there is a difficultly the port can be located fluoroscopically and adjustments made by the radiologist using fluoroscopic guidance. Contrast can be used instead of saline to assess filling and detect leakage from the tubing. This also allows a contrast swallow to be performed at the same time to assess the degree of restriction. Anastomotic strictures If anastomotic strictures are resistant to endoscopic dilatation, biodegradable or retrievable stents may be used often with good effect. Page 55 of 58

56 Fig. 36: A stent (black arrows) has been placed to treat a post RYGB stricture. The post-procedure contrast swallow shows a good result with free flow of contrast through the patent stent with no hold up at the stricture. References: - Leeds/UK Page 56 of 58

57 Anastomotic leaks Covered stents can occasionally be used for treating anastomotic leaks post bariatric surgery, however in the authors' experience the results have been disappointing and stent migration often occurs. Collections Although percutaneous CT drainage of collections does not address the underlying cause of the collection, it drains the acute sepsis and with appropriate gut rest can allow the source an opportunity to heal. Conclusion Obesity and rates of bariatric surgery are increasing. Knowledge of the common surgical procedures, post-operative anatomy and potential complications is essential for interpretation of post-operative imaging. CT and fluoroscopy are the mainstay techniques for assessment. Remember what complications you are looking for to allow you to decide on the best modality. Think about the restrictions on your equipment when agreeing to which examination you are doing. Radiology is VERY important in assessing these patients, as clinical assessment is difficult. References (1) Sjöström L, Narbro K, Sjöström CD et al. Effects of Bariatric Surgery on Mortality in Swedish Obese Subjects. N Engl J Med. 2007;23(357): (2) Baker MT. The history and evolution of bariatric surgical procedures. Surg Clin North Am 2011;91(6): (3) Quigley S, Colledge J, Mukerjee S et al. Bariatric Surgery: a review of normal postoperative anatomy and complications. Clin Radiol. 2011;66(10): (4) Brittenden J, Tolan DJM (eds.) (2012) Radiology of the Post Surgical Abdomen. London: Springer. Page 57 of 58

58 (5) Mehanna MJ, Birjawi G, Moukaddam HA et al. Complications of adjustable gastric banding, a radiological pictorial review. Am J Roentgenol. 2006;186: (6) Scheirey CD, Scholz FJ, Shah PC et al. Radiology of the laparoscopic Roux-enY gastric bypass procedure: conceptualization and precise interpretation of results. Radiographics 2006;26: (7) Bal BS, Finelli FC, Shope TR, Koch TR. Nutritional deficiencies after bariatric surgery. Nat Rev Endocrinol. 2012;8(9): (8) Shah S, Shah V, Ahmed AR, Blunt DM. Imaging in bariatric surgery: service set-up, post-operative anatomy and complications. Br J Radiolo 2011;84: (9) Chandler RC, Srinivas, Chintapalli KN et al. Imaging in Bariatric Surgery: A Guide to Postsurgical Anatomy and Common Complications. Am J Roentgenol. 2008; 190: Personal Information Page 58 of 58