Imaging of Bariatric Surgery: Normal Anatomy and Postoperative

Reviews and Commentary n State of the Art 327

urgery: S 1 © RSNA, 2014 Obesity is a disease that has reached epidemic proportions epidemic proportions that has reached Obesity is a disease During the the world. and around in the United States - an increas has become bariatric surgery past 2 decades, The for morbid obesity. of treatment ingly popular form include lap- performed procedures most common bariatric adjustable laparoscopic gastric bypass, Roux-en-Y aroscopic Fluo- gastrectomy. sleeve gastric banding, and laparoscopic and abdom- examinations gastrointestinal upper roscopic the major imaging tests are (CT) inal computed tomography forms of bar- patients after these various used to evaluate the article is to present The purpose of this iatric surgery. imaging findings and postop- and normal anatomy surgical at for these bariatric procedures complications erative after Complications CT. and examinations fluoroscopic include anastomotic leaks and gastric bypass Roux-en-Y jejunal ischemia, small bowel ulcers, marginal strictures, - intussusception, and recur obstruction, internal hernias, adjust- after laparoscopic gain. Complications weight rent malpositioned able gastric banding include stomal stenosis, gastric perforation, dilation, band slippage, pouch bands, and band- and port- band erosion, intraluminal volvulus, - gastrec complications after sleeve Finally, problems. related gastric and strictures, leaks include postoperative tomy The imaging features reflux. dilation, and gastroesophageal dis- are complications of bariatric surgery of these various cussed and illustrated.

maging of Bariatric of Bariatric maging I Normal Anatomy and Postoperative Postoperative and Anatomy Normal Complications radiology.rsna.org

). www.rsna.org/rsnarights. at us contact clients, or colleagues distribution for copies to your Note: Note: presentation-ready order To personal only. use non-commercial for your is copy This . Physicans should claim only the credit Physicans should claim . TM Volume 270: Number 2—February 2014 270: Volume Assess the imaging findings of fluoroscopic upper gastrointestinal examinations and CT for the complications associated with these three forms of bariatric surgery. Identify the major complications of these three forms of bariatric features. surgery and their relevant clinical Describe the surgical anatomy and normal imaging findings for three major forms of bariatric surgery, laparoscopic Roux-en-Y gastric bypass, including and laparoscopic sleeve adjustable gastric banding, gastrectomy. Online CME See www.rsna.org/education/search/ry

From the Department of Radiology, Hospital of the the Department of Radiology, From RSNA, 2014 RSNA,

commensurate with the extent of their participation in the activity. Statement Disclosure The ACCME requires that the RSNA, as an accredited provider of CME, obtain signed disclosure statements from the authors, editors, and reviewers for this activity. For this journal-based CME activity, author disclosures are listed at the end of this article. Accreditation and Designation Statement Accreditation Council for The RSNA is accredited by the Continuing Medical Education (ACCME) to provide continuing The RSNA designates medical education for physicians. this journal-based activity for a maximum of 1.0 AMA PRA Category 1 Credit n n Learning Objectives: the reader will the test, and taking After reading the article be able to: n Q 1 Philadelphia, 3400 Spruce St, University of Pennsylvania, VCU 19104 (M.S.L.); and Department of Radiology, PA Received December 4, (L.R.C.). VA Richmond, Medical Center, 2013; revision received January 7, requested revision 2012; 21; accepted March 24; final version accepted February Address (e-mail: March 24. correspondence to M.S.L. [email protected] Radiology: Marc S. Levine, MD MD Levine, Marc S. MD Carucci, Laura R. STATE OF THE ART: Imaging of Bariatric Surgery Levine and Carucci

besity has become a disease of ep- Obesity is measured by body mass primarily from early satiety caused by idemic proportions in the United index (BMI), a value based on a combi- the restrictive effect of a small, surgically OStates and around the world. In nation of weight and height (BMI 5 created gastric pouch rather than the 2004, the U.S. Centers for Disease Con- weight [kilograms]/height [meters]2). malabsorptive effect of small bowel by- trol and Prevention reported that 66% Overweight is defined as a BMI of pass (7). of American adults were overweight and 25–29 kg/m2, obesity is defined as a 32% suffered from obesity (1). It is the BMI of 30–35 kg/m2, and morbid obe- Surgical Anatomy second leading cause of preventable sity is defined as a BMI of greater than Roux-en-Y gastric bypass entails the death in the United States (after to- 35–40 kg/m2 (4). Bariatric surgery is by use of a stapler-cutter device to create bacco use), with more than 300 000 far the most invasive form of therapy for a staple line that partitions the stom- deaths annually (2). This epidemic obesity, so it is ideally reserved for pa- ach into a small fundal component (ie, also has enormous financial implications tients who fail to lose weight with diet, the gastric pouch) and a much larger for the United States, with obesity ac- exercise, and behavioral modification (5). excluded component (ie, the excluded counting for more than 20% of all na- Despite these guidelines, the use of bar- stomach) (Fig 1). The jejunum is then tional health expenditures (3). iatric surgery has increased dramatically, divided 25–50 cm distal to the ligament with five times as many bariatric surgi- of Treitz, and the distal limb (ie, the cal procedures performed in the United Roux limb, alimentary limb, or effer- Essentials States in 2003 as in 1998 (6). ent limb) is brought up and anasto- nn Radiologists should be familiar There are two surgical approaches mosed to the gastric pouch by means with the surgical anatomy and for achieving weight loss in obese pa- of an end-to-end or, more commonly, normal imaging findings for major tients: bypass procedures in which por- an end-to-side gastrojejunal anastomo- bariatric procedures, including tions of the gastrointestinal (GI) tract sis, creating a short, blind-ending jeju- Roux-en-Y gastric bypass, laparo- are bypassed to cause malabsorption, nal stump (8). The gastrojejunal anas- scopic adjustable gastric banding, and restrictive procedures in which tomosis can be antegastric or and laparoscopic sleeve gastric volume is decreased to induce retrogastric in location and is deliber- gastrectomy. early satiety. Jejunoileal bypass proce- ately fashioned as a small-caliber stoma dures have been largely abandoned be- (ranging 8–12 mm in diameter) to limit nn Fluoroscopic upper gastrointesti- cause of the degree of malabsorption in emptying of solid food from the gastric nal (GI) examinations with these patients (5). Proponents of bar- pouch and facilitate weight loss by water-soluble contrast agents and iatric surgery have instead advocated a means of a restrictive effect. The Roux abdominal CT are useful imaging variety of restrictive procedures (some- limb can be brought up to the gastric tests for detecting leaks after times combined with a bypass compo- pouch anterior or posterior to the Roux-en-Y gastric bypass; upper nent) to induce weight loss, including transverse colon; a posterior approach GI barium studies are better for Roux-en-Y gastric bypass, laparoscopic necessitates creation of a small defect detecting anastomotic strictures, adjustable gastric banding, and laparo- or window in the transverse mesocolon whereas CT optimizes detection scopic sleeve gastrectomy. This article through which the Roux limb passes of small bowel obstructions, reviews the most commonly performed (8–10). Finally, the proximal limb of internal hernias, and bariatric procedures, the normal imag- the divided jejunum (ie, the biliopan- intussusceptions. ing findings on fluoroscopic upper GI creatic limb or afferent limb) is anasto- nn Upper GI barium studies are and computed tomography (CT) stud- mosed to the small bowel 75–150 cm useful for showing postoperative ies, and the role of imaging studies in distal to the gastrojejunostomy to cre- complications such as stomal ste- detecting complications associated ate a common channel that continues nosis, band slippage, and gastric with these procedures. into the ileum (8–10). The jejunojeju- volvulus after laparoscopic ad- nostomy is usually created by means of justable gastric banding, and for a side-to-side anastomosis to decrease assessing routine band Laparoscopic Roux-en-Y Gastric the risk of stricture formation. adjustments. Bypass nn Fluoroscopic upper GI examina- Laparoscopic Roux-en-Y gastric bypass tions with water-soluble contrast is the most popular bariatric procedure Published online 10.1148/radiol.13122520 agents and CT are useful imaging performed in the United States because Content code: tests for detecting leaks after it is associated with greater sustained Radiology 2014; 270:327–341 sleeve gastrectomy, and barium weight loss and higher long-term success studies are also useful for rates than other forms of bariatric sur- Abbreviations: showing strictures or gastric gery. Surgical bypass of a variable GI = gastrointestinal SBO = small bowel obstruction outlet obstruction as a complica- length of small bowel is a contributing tion of this surgery. factor, but weight loss is thought to result Conflicts of interest are listed at the end of this article.

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Figure 1 Figure 2 Figure 3

Figure 3: Normal appearance of Roux-en-Y gastric bypass at CT. Axial CT image after oral and intravenous contrast material administration shows Figure 1: Diagram shows normal surgical anatomy small gastric pouch (P) separated by staple line Figure 2: Normal imaging findings after Roux-en-Y after Roux-en-Y gastric bypass. A staple line partitions from excluded stomach (ES) laterally. Jejunal Roux gastric bypass. Supine spot image from single- the stomach into a small fundal pouch (white arrow) limb (J) is anastomosed to gastric pouch anteriorly. contrast upper GI barium study shows opacified and a much larger excluded stomach (white arrow- Note oral contrast material opacifying pouch and gastric pouch (white arrows), with barium entering head). The jejunal Roux limb is joined proximally to Roux limb, whereas excluded stomach is not Roux limb (black arrows) and blind-ending jejunal the fundal pouch via a gastrojejunal anastomosis opacified. (black arrowhead) and distally to the biliopancreatic stump (white arrowhead). Note widely patent side- limb via a jejunojejunal anastomosis (black arrow). to-side jejunojejunostomy (black arrowheads) visual- (Reprinted, with permission, from reference 12.) ized in profile. Gaseous distention of small bowel loops resulted from aerophagia (not administration ness (14,15). Identification of the of effervescent agent). gastric pouch, gastrojejunal anastomosis, jejunal Roux limb, jejunojejunal Normal Imaging Findings anastomosis, and biliopancreatic limb Upper GI examination.—The gastric copy as it passes from the esophagus into on CT scans is essential for detecting pouch typically appears on upper GI the gastric pouch and then from the potential complications such as internal studies as a small structure with a vol- pouch into the Roux limb via the gastro- hernias and small bowel obstructions. ume of 15–20 mL, though considerable jejunal anastomosis. This approach fa- Positive oral contrast material adminis- variation may be encountered. The gas- cilitates detection of staple line break- tered just prior to image acquisition trojejunal anastomosis should be visual- down as well as leaks or strictures at helps differentiate the gastric pouch ized in profile (without overlap between the gastrojejunal anastomosis that later and Roux limb from the excluded stom- the gastric pouch and jejunum) to pro- may be obscured by overlying loops of ach and biliopancreatic limb, which are vide a reasonable estimate of anasto- opacified small bowel (12). not opacified (Fig 3). The volume of ad- motic diameter. When the jejunum is When the Roux limb is retrocolic, it ministered oral contrast material will connected to the inferior aspect of the is brought up to the gastric pouch via a depend on the patient’s tolerance and pouch, the gastrojejunal anastomosis is surgically created window in the trans- symptoms. The Roux limb should be readily visualized on frontal views, but verse mesocolon. As a result, there may followed along its antecolic or retrocolic when the jejunum is connected to the be a short segment of circumferential course to the jejunojejunal anastomo- anterior or posterior aspect of the narrowing of the Roux limb where it tra- sis, typically in the left midabdomen. pouch, steep oblique or lateral views verses this window and is sutured to the The excluded stomach should be visual- may be required to visualize the anasto- surrounding transverse mesocolon (13). ized on CT images and is normally col- mosis in profile (11). In the absence of This finding should not be mistaken for lapsed in these patients (Fig 3) (14,16). obstruction, contrast material should an ischemic stricture or other cause of Failure to identify the excluded stomach pass freely into the Roux limb. The jejunal narrowing. could result in misdiagnosis of this study is not completed until the small Abdominal CT.—After gastric by- fluid-filled structure as an abscess. CT bowel is opacified beyond the jejunoje- pass surgery, CT examinations are ide- also enables visualization of fluid- and/ junostomy, so the jejunojejunal anasto- ally performed with both oral and or gas-filled loops of small bowel in the mosis can also be assessed (Fig 2). intravenous contrast agents. Because of biliopancreatic limb, which is not gen- When obtaining upper GI studies in the size and girth of bariatric patients, erally identified on barium studies be- patients with Roux-en-Y gastric bypass, it may be necessary to adjust technical cause intestinal peristalsis often it is important to follow the head of the factors such as kilovoltage, milliamper- prevents retrograde filling of this limb column of contrast material at fluoros- age, field of view, and collimation thick- with barium.

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Figure 4 Figure 5 blind-ending jejunal stump or jejunojejunostomy (12). Most patients with anastomotic leaks require repeat surgery, but small sealed-off leaks may be successfully treated with percutaneous drainage catheters and antibiotics. Whatever the site of origin, an extraluminal leak should be differentiated from breakdown of a gastric staple line and the development of a so-called gastrogastric fistula that has very different implications for patient management (see later Figure 5: Roux-en-Y gastric bypass with postop- section on recurrent weight gain). erative anastomotic leak at CT after oral but not Anastomotic narrowing and stric- intravenous contrast material administration. Axial tures.—Transient anastomotic narrow- CT image shows extravasated contrast material in ing and obstruction may occur during the perisplenic space (L), indicating a postoperative early postoperative period secondary to leak. Note jejunal Roux limb more medially (J). residual edema and spasm in this re- Figure 4: Roux-en-Y gastric bypass with postop- gion (8). Upper GI examinations may erative anastomotic leak. Supine spot image from reveal focal narrowing of the gastrojeju- upper GI examination with water-soluble contrast examinations with water-soluble contrast nal anastomosis and thickened, irregular material shows focal extravasation from left lateral agents 1–2 days after surgery as the pre- folds in the Roux limb abutting the anas- aspect of gastrojejunal anastomosis into two short ferred imaging test for ruling out leaks tomosis. These findings usually resolve tracks (black arrows) and adjoining extraluminal after gastric bypass surgery (12,17). within several days. collection (white arrows). Note contrast material When upper GI examinations are Strictures at the gastrojejunal anas- passing through and around drain (arrowhead) performed, scout images should be ob- tomosis have been reported in 3%–9% that communicates with inferior aspect of this of patients (20). These strictures typi- collection. tained to detect loculated or free extraluminal gas as well as radiopaque cally develop 4 weeks or more after sur- staple lines that otherwise could be gery; they may be caused by postsurgi- Complications mistaken for small leaks during the cal scarring at the anastomosis or by Leaks.—Extraluminal leak is the most fluoroscopic examination. After water- chronic ischemia resulting from tension serious early complication of Roux-en-Y soluble contrast material has been ad- on the gastrojejunostomy (21). Affected gastric bypass, occurring in up to 5% of ministered, most leaks from the gastro- individuals usually present with postpran- patients (12). Between 69% and 77% of jejunal anastomosis are best visualized dial vomiting, bloating, and upper ab- leaks involve the gastrojejunal anasto- with the patient in a supine or supine dominal pain, sometimes associated with mosis (12,17), but other less common left posterior oblique position, appear- rapid weight loss. Obstructive symptoms sites of perforation include the gastric ing as blind-ending tracks or sealed-off from strictures at the gastrojejunal anas- pouch, blind-ending jejunal stump, and collections abutting the anastomotic re- tomosis tend to develop shortly after jejunojejunostomy (12). Leaks usually gion (Fig 4) or, less frequently, as free meals, whereas vomiting associated with occur within 10 days of surgery; early leaks into the peritoneal cavity (12). small bowel adhesions, internal hernias, detection is critical because of the risk of About 75% of these leaks extend to the or strictures at the jejunojejunal anasto- abscess formation, peritonitis, and sep- left of the gastrojejunal anastomosis as mosis may occur 1 hour or more later. sis, with a mortality rate of more than extraluminal collections in the left up- Anastomotic strictures usually ap- 5% (12). Affected individuals may pre- per quadrant on upper GI studies or CT pear on upper GI studies as short seg- sent with leukocytosis, fever, abdominal scans, sometimes continuing superiorly ments of smooth narrowing at the gas- pain, and tachycardia (12). Although one into the subphrenic space (Fig 5) (12). trojejunal anastomosis (Fig 6) (18). If study found that a heart rate exceeding Subtle leaks may only be recognized in- obstruction is present, the gastric 120 beats per minute was the single directly by contrast material entering a pouch may be dilated, and emptying of most reliable sign of perforation (18), surgical drain near the gastrojejunal barium into the Roux limb may be de- the clinical symptoms are often nonspe- anastomosis. If no leak is detected with layed. Strictures at anastomoses that cific, and the physical examination may a water-soluble contrast agent, high- have an inferior location in relation to be limited by the large body habitus of density barium should be administered the gastric pouch are readily detected these patients. Because of clinical diffi- to demonstrate subtle leaks that might with patients in the frontal position, culties in diagnosing postoperative leaks, otherwise be missed (19). Less com- whereas strictures at anastomoses that some authors advocate routine upper GI monly, leaks may be detected from the have an anterior or posterior location

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Figure 6 Figure 7 Figure 8

Figure 7: Roux-en-Y gastric bypass with marginal ulcer. Supine right posterior oblique spot image from single-contrast upper GI barium study shows discrete ulcer niche (arrow) in jejunal Roux limb abut- Figure 6: Roux-en-Y gastric bypass with anasto- ting gastrojejunal anastomosis. This patient motic stricture. Steep right posterior oblique spot presented with abdominal pain and melena. image from single-contrast upper GI barium study Figure 8: Roux-en-Y gastric bypass with giant shows gastrojejunal anastomosis in profile, enabling jejunal ulcers. Supine right posterior oblique spot visualization of a tight anastomotic stricture (arrow). image from single-contrast upper GI barium study sis (Fig 7) (26). They usually occur as This stricture was not visible on supine spot images shows giant ulcer (large black arrow) in jejunal Roux solitary ulcers of varying size. Most because of overlap between lower end of gastric limb abutting gastrojejunal anastomosis (small black pouch and upper end of jejunal Roux limb that ob- marginal ulcers respond to medical arrow) and second giant ulcer (large white arrow) scured anastomotic region. therapy with antisecretory agents (ie, more distally in Roux limb. Note thickened, spiculated proton pump inhibitors) (26), though folds (small white arrows) in adjacent small bowel. surgical revision of the gastrojejunal (Reprinted, with permission, from reference 28.) can be missed on frontal views because anastomosis occasionally may be re- of overlap between the pouch and Roux quired for intractable ulcers (24). limb that obscures the anastomosis Jejunal ischemia.—Some patients (11). As a result, steep oblique or lat- develop acute ischemia of the Roux contour, tapered margins, and effaced eral views may be required to visualize limb because of tension on the surgi- or obliterated folds (27). CT may also these strictures by eliminating overlap cally mobilized jejunum that compro- reveal a long segment of jejunal narrow- and showing the anastomosis in profile mises its vascular supply (21). Affected ing with bowel wall thickening and mu- (Fig 6) (11). Patients with anastomotic individuals typically present with se- ral stratification (ie, a target sign). In strictures often have an excellent re- vere abdominal pain, upper GI some patients, surgical resection of the sponse to endoscopic dilation of the bleeding, or nausea and vomiting ischemic segment is required for treat- strictures (22), but some patients may during the early postoperative period ment of obstruction (27). require multiple dilation procedure. (27). Barium studies may reveal thick- Other patients with chronic jejunal Marginal ulcers.—Ulcers at the ened, spiculated folds or thumb ischemia may develop one or more gi- gastrojejunal anastomosis (ie, mar- printing secondary to submucosal ant (ie, 2.5 cm or larger) ulcers in the ginal ulcers) have been reported in edema and hemorrhage, and CT may Roux limb abutting the gastrojejunal 3%–13% of patients after Roux-en-Y reveal a thickened jejunal wall in the anastomosis or at a discrete distance gastric bypass (23–25). It has been ischemic segment, with edema of the from the anastomosis (Fig 8) (27,28). postulated that these ulcers develop as mesentery and engorged mesenteric These individuals are more likely to re- a result of chronic exposure of the mu- vessels. Mild jejunal ischemia is often quire resection of the diseased jejunum cosa to acid entering the Roux limb self-limited, but more severe ischemia and revision of the anastomosis than (24). Affected individuals typically pre- can lead to small bowel infarction. other patients with marginal ulcers (28). sent with epigastric pain or upper GI In contrast, chronic ischemia of the The presence of one or more giant, non- bleeding. Marginal ulcers are mani- Roux limb may cause intractable nau- healing ulcers in the Roux limb after fested on barium studies as discrete sea and vomiting secondary to the de- gastric bypass surgery should therefore ulcer niches at the gastrojejunal anas- velopment of a jejunal stricture (27). suggest chronic jejunal ischemia and the tomosis or, even more commonly, in Barium studies may reveal a segment of need for aggressive medical or even sur- the Roux limb abutting the anastomo- tubular narrowing that has a smooth gical management of these patients.

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Figure 9 Figure 10

Figure 10: Roux-en-Y gastric bypass with obstruc- Figure 9: Roux-en-Y gastric bypass with obstruction of jejunal Roux limb at CT. (a, b) Axial CT images after tion of biliopancreatic limb. Axial CT image after oral oral and intravenous contrast material administration show dilated gastric pouch (P) and jejunal Roux limb (J) and intravenous contrast material administration extending into left midabdomen, with abrupt transition due to obstruction at jejunojejunal anastomosis shows a dilated, gas- and fluid-containing excluded (arrow). The excluded stomach (ES) is decompressed. stomach (ES), duodenum (D), and biliopancreatic limb (BP). The excluded stomach should be collapsed after Small bowel obstruction.—Small lapsed Roux limb (Fig 10). These find- Roux-en-Y gastric bypass. Recognition of surgical bowel obstruction (SBO), which occurs ings should be highly suggestive of a anatomy and collapsed jejunal Roux limb (arrow) is in up to 5% of patients, may be caused closed-loop obstruction. essential for establishing the diagnosis of this by adhesions, internal hernias, anterior C: Type C is SBO at the level of the closed-loop obstruction. abdominal wall hernias, strictures at the common small bowel channel distal to jejunojejunal anastomosis, and, rarely, the jejunojejunostomy, with dilation of is particularly important because the intussusceptions (29–31). An ABC clas the Roux limb and biliopancreatic limb clinical findings are often nonspecific sification system has been devised for above the jejunojejunal anastomosis. (31,34,35). three different types of SBO seen on Internal hernias.—Though adhe- The diagnosis of internal hernias on barium studies and CT scans after sions are the most common cause of imaging studies requires knowledge of Roux-en-Y gastric bypass based on the SBO after open Roux-en-Y gastric by- the postoperative anatomy and recogni- location of alterations to the GI tract pass, internal hernias are the most tion of changes in the configuration of relative to the jejunojejunal anastomo- common cause after the laparoscopic the bowel. Small bowel loops may be sis (32,33), as follows: form of surgery (29–31). The low clustered together in abnormal loca- A: Type A is SBO with a dilated ali- frequency of adhesions with laparo- tions on barium studies and CT images, mentary limb (Roux limb) and decom- scopic technique enables the small often displacing other bowel and associ- pressed biliopancreatic limb. This type is bowel to retain its mobility, increasing ated with migration of an anastomotic manifested on barium studies by a di- the susceptibility to internal hernias jejunojejunal suture line. This suture lated Roux limb obstructed at or above (34,35). This complication of Roux-en- line is most often displaced from its the jejunojejunostomy (Fig 9). Recogni- Y gastric bypass develops in about 3% typical location in the left midabdomen tion of the dilated Roux limb and col- of patients, typically occurring as a into the left upper quadrant, but it can lapsed excluded stomach and duo- late finding (35). also be displaced into the right midab- denum may be difficult on CT studies. Internal hernias after Roux-en-Y domen (31). A focal cluster of small B: Type B is SBO with a dilated bil- gastric bypass usually result from her- bowel loops is most often seen in the iopancreatic limb. This type is a closed- niation of small bowel loops through a left midabdomen (90%), but clustered loop obstruction that causes marked defect in the transverse mesocolon bowel can be located anywhere in the distention of the excluded stomach and (for a retrocolic Roux limb), a defect abdomen and pelvis (31). Barium stud- biliopancreatic limb at or above the je- in the small bowel mesentery (for a je- ies may also reveal small bowel limbs junojejunostomy. Affected individuals junojejunal anastomosis), or a defect entering and exiting the hernia with re- are at high risk for perforation unless posterior to the Roux limb (ie, Peters- tention of barium within these loops prompt therapy is instituted. Because en defect). Incarceration of small (14,31). One advantage of the barium the biliopancreatic limb and excluded bowel in an internal hernia can lead to study over CT is the ability to visualize stomach are not usually opacified on obstruction, infarction, and perfora- changes in the configuration of the barium studies, the diagnosis is more tion of strangulated loops. As a result, small bowel during the course of the ex- likely to be made at CT by visualization internal hernias can be fatal if diagno- amination. The diagnosis of an internal of a dilated, fluid-filled excluded stom- sis and treatment of this complication hernia should be suspected on CT im- ach and biliopancreatic limb with a col- are delayed. A high index of suspicion ages when a cluster of small bowel

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Figure 11

Figure 11: Roux-en-Y gastric bypass with obstructing internal hernia. (a, b) Axial CT images after oral but not intravenous contrast material administration show a collapsed gastric pouch (P) and excluded stomach (ES). Note dilated, clustered small bowel loops displaced into left upper quadrant (arrows) with resulting SBO. (c) Overhead radiograph from small bowel follow-through in same patient also shows clustered, dilated, and displaced small bowel loops in left upper quadrant (arrows), displacing other bowel. The excluded stomach (ES) and duodenum (D) are opacified as a result of retrograde flow of barium via jejunojejunostomy. This patient had a surgically proved transmesocolic internal hernia. loops is seen in an atypical location, es- gastrogastric fistula because their odenum (Fig 13). If there is opacifica- pecially the left upper quadrant above staple line dehiscence has restored tion of the biliopancreatic limb and the transverse mesocolon (Fig 11). CT communication between the gastric duodenum, however, a barium study also enables visualization of changes in pouch and the excluded stomach. may be required to differentiate staple the mesentery, such as stretching and When there is complete surgical tran- line breakdown from retrograde filling swirling of vessels and mesenteric en- section of the pouch and separation of the excluded stomach via the bilio- gorgement (31,36–38). from the remaining stomach, commu- pancreatic limb (14,16,40). Intussusception.—Small bowel in- nication between the pouch and the Breakdown of the gastric staple tussusceptions typically occur at or excluded stomach results from the de- line with a leak into the excluded stom- near the jejunojejunal anastomosis, velopment of a leak with subsequent ach has been reported in about 3.5% with the staple line at this anastomosis fistula formation (40). of patients, occurring with equal presumably acting as the lead point for Upper GI studies may be performed frequency during the early and late the intussusception. Altered small to determine whether staple line postoperative periods (40). Early leaks bowel motility near the anastomosis breakdown is responsible for recurrent into the excluded stomach are associ- may also be a contributing factor. These weight gain. The fluoroscopist should ated with extraluminal leaks in nearly intussusceptions may be transient or carefully assess the head of the barium 90% of patients (40) and may undergo fixed and are a rare cause of SBO after column with the patient in an upright spontaneous healing, so additional sur- gastric bypass surgery (39). or semi-upright position to ascertain gery is not always required. In con- Recurrent weight gain.—The pri- whether barium has emptied from the trast, leaks into the excluded stomach mary mechanism for weight loss after gastric pouch via the gastrojejunal during the late postoperative period Roux-en-Y gastric bypass is the restric- anastomosis or whether it has tra- are more likely to be associated with tive effect created by a small gastric versed a dehisced portion of the staple recurrent weight gain and less likely to pouch, causing early satiety after in- line to enter the excluded stomach (Fig undergo spontaneous healing (40). In gestion of even small quantities of solid 12a). Later in the study or on over- the past, it has been suggested that food (7). As a result, one of the major head radiographs, barium may reflux small leaks into the excluded stomach causes of recurrent weight gain is par- into the biliopancreatic limb and ex- are of little clinical importance and tial or complete breakdown of the gas- cluded stomach, so it becomes far that only large leaks are likely to cause tric staple line that enables food to more difficult to assess whether the recurrent weight gain because of rapid enter the excluded stomach, elimi- staple line is disrupted (Fig 12b). Sta- emptying of the gastric pouch (41). nating the restrictive effect of the ple line breakdown should also be sus- However, others have found that even pouch. Affected individuals become pected on CT studies when contrast small leaks into the excluded stomach aware that they have lost the sensation material is visualized in the excluded may be associated with recurrent of early satiety created by their sur- stomach in the absence of opacifica- weight gain, necessitating surgical revi- gery. In effect, these patients have a tion of the biliopancreatic limb and du- sion (40).

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Figure 12 Laparoscopic Adjustable Gastric Banding Since its introduction by Belachew et al in 1993 (42) and its approval for use in the United States in 2001 (43), laparoscopic adjustable gastric banding has become an increasingly popular form of restrictive surgery for morbid obesity. Gastric banding is a less invasive procedure than Roux-en-Y gastric bypass that produces comparable short-term weight loss with fewer complications (44,45). The band is placed around the proximal stomach (creating a small gastric pouch), and saline is intermittently administered into or withdrawn from the band to increase or decrease its re- Figure 12: Roux-en-Y gastric bypass with breakdown of staple line. (a) Supine spot image from single- strictive effect on the stomach. Unlike contrast upper GI barium study shows focal disruption of proximal end of staple line, with barium passing other forms of bariatric surgery, this from gastric pouch laterally into excluded stomach (black arrows) via gastrogastric fistula (arrowheads). procedure therefore requires periodic (White arrow 5 gastrojejunal anastomosis.) (b) Subsequent supine spot image from same study shows adjustment of the band stoma. Stomal extensive filling of jejunal Roux limb, with barium also opacifying biliopancreatic limb and excluded stom- adjustments should ideally be made on ach (white arrows) secondary to retrograde filling via jejunojejunal anastomosis. As a result, it is difficult to the basis of the patient’s weight loss differentiate staple line disruption from retrograde filling of excluded stomach on this image. (Black arrow curve and symptoms. = barium in gastric pouch.) Surgical Anatomy Figure 13 An adjustable silicone gastric band is placed around the stomach about 2 cm below the gastroesophageal junction to create a small gastric pouch above the band (Fig 14) (9,10,46,47). The band is sutured to the adjacent wall of the stomach to decrease the chances of band slippage (10). The band has an in- flatable inner sleeve that is connected via tubing to a subcutaneous port in the right or, less commonly, left abdominal wall. This configuration enables adjustment of the band by altering the amount of fluid within the band via a needle inserted into the subcutaneous port. Per- Figure 13: Roux-en-Y gastric bypass with staple line breakdown diagnosed at CT. (a) Axial and (b) iodic adjustment of the band is per- coronal CT images after oral and intravenous contrast material administration show contrast material formed by administering small volumes opacifying gastric pouch (P) and excluded stomach (ES) without opacification of duodenum (D), findings of saline into the band in an incremen- highly suggestive of staple line breakdown. When contrast material is also identified in duodenum and tal fashion to gradually tighten the band biliopancreatic limb, however, a barium study may be required to differentiate staple line disruption from and increase its restrictive effect, pro- retrograde filling of excluded stomach (J 5 jejunal Roux limb). moting weight loss. Conversely, saline can be removed from the band if the patient experiences obstructive symp- Recurrent weight gain may also re- sis, leading to recurrent weight gain. toms because the band is too tight. sult from widening of the gastrojejunal The diameter of the gastrojejunal anastomosis with rapid emptying of anastomosis should therefore be as- Normal Imaging Features the gastric pouch, so even a small sessed when evaluating patients for Upper GI examination.—After place- pouch may no longer produce early sa- recurrent weight gain after gastric by- ment of the gastric band, an upper GI tiety if there is a widened anastomo- pass surgery. examination may be performed with an

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Figure 14 Figure 15

Figure 14: Diagram shows laparoscopic adjustable gastric band surrounding proximal stomach, producing a small gastric pouch above band. When saline is introduced into band via subcutaneous port, luminal narrowing causes early satiety and weight loss. (Reprinted, with permission, from reference 51.) Figure 15: Utility of routine barium study after gastric band adjustment to assess caliber of lumen where it traverses band. (a) Initial single-contrast upper GI barium study after administration of 2 mL of saline via subcutaneous port into band shows marked narrowing of lumen (arrow) traversing band with proximal dila- Figure 16 tion. (b) Repeat study after removal of 1 mL of saline shows only mild narrowing of lumen (arrow) with normal-caliber esophagus above band. On both studies, note normal position of band beneath medial aspect of left hemidiaphragm and oblique orientation with lateral edge superior to medial edge.

intersecting lines through the spinal band. The anterior abdominal wall should column and horizontal axis of the band be included in the field of view to assess (ie, the phi angle) has a normal range the soft tissues surrounding the subcu- between 4° and 58° (47). The band is taneous port. connected by contiguous tubing to the The radiopaque band can be identi- subcutaneous port. fied around the proximal stomach on Administration of contrast material CT images (Fig 16), and the attached typically reveals a small gastric pouch tubing can be seen extending through above the band with tapered narrowing the peritoneal space and rectus muscles of the lumen where it traverses the band before connecting to the subcutaneous Figure 16: Expected appearance of laparoscopic stoma and free passage of contrast ma- port along the anterior rectus sheath. gastric band at CT. Axial CT image after oral and terial into the larger portion of the All components of the device and adja- intravenous contrast material administration shows stomach below the band (Fig 15b). It is cent soft tissues should be assessed. CT band device (arrowhead) positioned around proximal important to place the patient in a frontal may be helpful in evaluating for a source stomach. The band is connected via tubing (arrow) or slightly right posterior oblique posi- of infection and in assessing soft tissue to an injectable port (not see on this image) along tion at fluoroscopy, so the stoma can be changes related to the tubing and reser- anterior rectus sheath. assessed in profile without being ob- voir (17,48). scured by the opacified fundus (17,41). orally administered water-soluble contrast The normal diameter of the gastric pouch Complications agent to confirm the location of the band is usually about 4 cm, corresponding to Stomal stenosis.—The most common in relation to the stomach, assess the a volume of 15–20 mL (10). complication after gastric banding is caliber of the lumen through the band, Abdominal CT.—CT is ideally per- stomal stenosis (46). This complication and evaluate for postoperative leaks. formed with both positive oral and in- occurs when the band is too tight, causing A scout image should be obtained to doc- travenous contrast material. CT technical excessive luminal narrowing and obstruc- ument the location of the band, which factors may be adjusted to accommo- tion. Affected individuals usually present normally has an oblique orientation with date for the patient’s large body habitus with nausea and vomiting, regurgitation, its lateral side above its medial side just (15). Coronal, sagittal, and oblique mul- dysphagia, or upper abdominal pain. beneath the medial aspect of the left tiplanar reformatted images are benefi- Barium studies may reveal excessive hemidiaphragm. The angle formed by cial for evaluating the gastric pouch and narrowing of the lumen where it tra-

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verses the band, with dilation of the been adequately adjusted (Fig 15b). instead surrounds the stomach more proximal stomach, pouch-esophageal Swenson et al (51) found that a barium distally, with herniation of the gastric reflux, and slow emptying of barium study after band adjustment yielded fundus above the band. Band slippage through the band into the remaining useful information leading to readjust- is often associated with luminal nar- stomach (Fig 15a) (46). In extreme ment of the band after 7% of routine rowing and obstruction by the band. cases, there may be high-grade lu- band adjustments. As a result, affected individuals may minal obstruction by the band. If stomal Malpositioned band.—Malpositioning present with vomiting, regurgitation, and stenosis causes a food impaction above of the band is an unusual complication food intolerance (46). Severe band slip- the band, the patient may present with that occurs at the time of surgical place- page occasionally may be complicated abrupt onset of severe vomiting and ment, most often when this procedure is by the development of gastric volvulus regurgitation and an inability to tol- performed by an inexperienced surgeon. with infarction and perforation of the erate solids or even liquids by mouth. If the band is placed in the perigastric fat, stomach, a potentially life-threatening In such cases, the impacted food may it fails to encompass the stomach, so there condition (see later section, Gastric be recognized on barium studies as a is no restrictive effect on the lumen. In Volvulus). radiolucent defect above the band. other patients, the band inadvertently may Band slippage is often recognized on When stomal stenosis is found on be placed inferiorly around the lower abdominal radiographs by increased sep- barium studies in patients with obstruc- stomach, causing gastric outlet ob- aration between the gastric band and tive symptoms, the band should be de- struction. the medial aspect of the left hemidia- flated to increase luminal caliber and re- Pouch dilation.—Acute pouch dilation phragm. The slipped band also tends to lieve the patient’s symptoms. A usually results from marked stomal nar- have a more horizontal orientation, with follow-up study should be obtained im- rowing secondary to overfilling of the a phi angle greater than 58° (Fig 17a) mediately after band adjustment to band or from distal band slippage and (47). As the stomach herniates superi- document that luminal caliber has in- obstruction (see next section). In this orly through a slipped gastric band, the creased adequately and that barium setting, the band should be deflated to weight of the herniated stomach some- passes freely through the band. If a prevent further complications, including times causes the band to tilt along its food impaction is present above the irreversible pouch dilation and progres- horizontal axis, so the anterior and pos- band, deflation of the band may cause the sive band slippage (17,48,52). Chronic terior sides of the band are no longer impaction to resolve spontaneously, but pouch dilation may also develop in the superimposed, producing an O-shaped endoscopic retrieval of this food is re- presence of a normal stomal diameter and configuration (also known as the O sign), quired if the impaction persists is usually secondary to chronic volume a finding highly suggestive of distal band following band deflation. overload of the pouch in patients who fail slippage (55). If the slipped band is caus- It is important to remember that to modify their eating habits after band ing obstruction, an air-fluid level may be weight loss results from the restrictive placement (46,49). This complication has present in a dilated gastric pouch above effect of the band, so some degree of been reported in 3%–8% of patients the band (Fig 17a). stomal narrowing is required for the (52,53). Barium studies may show con- Barium studies can readily demon- patient to experience early satiety centric dilation of the gastric pouch with strate distal slippage of the band, with and weight loss. Nevertheless, there is retained food in the pouch, esophageal the band surrounding the lower gastric disagreement about the optimal degree dilation above the pouch, and a normal fundus, body, or even antrum. This com- of stomal narrowing after band place- to widened stoma (46). In this setting, plication is often associated with stomal ment, with some authors favoring a lu- nutritional counseling is required (48). narrowing and obstruction manifested minal diameter of only 3–5 mm (49,50). Distal band slippage.—Distal band by eccentric dilation of the gastric pouch Though some surgeons routinely ad- slippage is a relatively common compli- and delayed emptying of barium just gastric bands in their office without cation of band placement, occurring in through the band (Fig 17b). The di- benefit of fluoroscopy or a barium 4%–13% of patients (46). This compli- lated gastric pouch is usually posterior study, others perform the adjustments cation is thought to result from recurrent and inferior in patients with posterior in conjunction with a radiologist in the vomiting, overinflation of the band, or slippage and anterior and superior in fluoroscopy suite, not only to utilize faulty surgical technique and can be pos- patients with anterior slippage (46). fluoroscopy for accessing the subcutane- terior or anterior (54). Posterior slip- When band slippage is documented ous port, but also to obtain barium page is associated with upward herniation on barium studies, all residual fluid is usu- studies immediately after each adjust- of the posterior gastric wall through the ally removed from the band to decrease ment. If there is excessive luminal nar- band, whereas anterior slippage is asso- luminal narrowing and alleviate or pre- rowing or obstruction (Fig 15a), some of ciated with downward displacement of vent obstruction. The barium study the administered saline can be with- the band over the anterior aspect of the should be repeated immediately after drawn from the band via the subcutane- stomach (46). With both forms of slip- band adjustment to document that the ous port before repeating the barium page, the band is no longer positioned band stoma is now patent. If not, surgical study to document that the band has near the gastroesophageal junction, but removal of the band may be required. If

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Figure 17 Figure 18

Figure 18: Distal band slippage with gastric volvulus. Supine spot image from single-contrast upper Figure 17: Distal band slippage with obstruction. (a) Upright scout image of upper abdomen shows GI barium study shows marked distal slippage of abnormal position of band (black arrow), which is located more inferiorly than usual and has a transverse band (white arrow), with converging gastric folds orientation (with phi angle of about 90°). Also note air-fluid level within gastric pouch (white arrow) above (black arrow) due to twisting of dilated stomach band. (b) Upright frontal spot image from single-contrast upper GI barium study shows marked narrowing above band. Also note high-grade obstruction with and high-grade obstruction of lumen (arrow) by slipped band, with markedly dilated gastric pouch above no barium entering stomach distal to band and band. This obstruction resolved after removal of all fluid from band. dilated, fluid-filled esophagus proximally (arrowheads). This patient made a complete recovery after the band stoma is patent, a follow-up bar- with twisting of the prolapsed proximal the band was removed surgically. ium study should be performed 7–14 stomach around the band, causing days later to determine whether the closed-loop obstruction (57). This con- deflated band has returned to its usual dition is potentially life-threatening be- but late complication of laparoscopic ad- location beneath the left hemidia- cause the torsed stomach is at risk for justable gastric banding that occurs in phragm and whether pouch dilation strangulation, ischemia, and infarction. less than 2% of patients (58). This com- has resolved. If so, additional saline can When high-grade obstruction is pre- plication may result from high pres- be administered incrementally into the sent, affected individuals are likely to sures generated by the inflated band, band through a new series of periodic present with severe nausea and vomit- with pressure necrosis of the adjacent adjustments to promote further ing (57). Barium studies may reveal gastric wall and subsequent erosion of weight loss. If band slippage persists twisting of the prolapsed stomach the band into the lumen. There usu- on one or more follow-up barium stud- around the band, causing the body of ally is incomplete erosion of the band ies, however, the band should be surgi- the stomach to rotate upwards and to into the stomach (58), but the entire cally repositioned, removed, or re- the left, so it is located above the fundus band occasionally may erode into the placed. (57). This is often associated with lumen (59). With complete intraluminal Perforation.—Acute gastric perfora- marked narrowing and high-grade ob- erosion, the band can migrate distally tion is a rare complication of laparoscopic struction of the lumen where it tra- and become lodged in the gastric an- gastric banding, occurring in less than verses the band (Fig 18) (57). If ischemia trum, duodenum, or proximal jejunum, 1% of patients (46,56). This complica- and/or infarction of the stomach are causing mechanical obstruction (60–62). tion presumably results from trauma to present, CT scans may show thickening Rarely, the intraluminal band can even the gastric wall at surgery. Affected in- of the gastric wall and gastric pneu- migrate in a retrograde fashion to the dividuals typically present with upper matosis. Even in patients with severe gastroesophageal junction, causing ob- abdominal pain, fever, leukocytosis, vascular compromise, however, this struction at the cardia (59). Intraluminal and tachychardia. Upper GI studies gastric ischemia often resolves after the erosion of the band usually warrants may reveal contained or even free extrav- band is removed and the normal vas- band removal because of the risk of ob- asation of water-soluble contrast mate- cular supply to the stomach is re- struction, severe upper GI bleeding, or rial from the site of perforation, and stored. Gastric volvulus therefore perforation (49,58). CT images may show extraluminal gas represents an indication for immediate Intraluminal band erosion into the or fluid collections in the left upper surgery and urgent removal of the band stomach may be manifested on upper quadrant (10). before the development of gastric in- GI examination or CT scan by passage of Gastric volvulus.—Gastric volvulus is farction and perforation (57). barium around the intraluminal portion a rare complication of gastric banding Intraluminal band erosion.—Band of the band (Fig 19) (63) or around all that occurs when there is band slippage erosion into the gastric lumen is a rare sides of the band if it has eroded com-

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Figure 19 Figure 20 Figure 21

Figure 19: Gastric band partially eroding into gastric lumen. Axial CT image after oral and intravenous contrast material administration shows that lateral aspect of band device has eroded into lumen of stomach. Note contrast material (arrow) and a tiny Figure 21: Diagram shows normal surgical focus of gas medial to eroded portion of band. anatomy after laparoscopic sleeve gastrectomy. Note how stomach is resected along greater curvature of fundus, body, and proximal antrum, pro- Gastric band completely eroding into Figure 20: ducing a narrow, banana-shaped pouch along lesser gastric lumen with partial obstruction. Lateral spot pletely into the lumen (Fig 20) (59). curvature. When an intraluminal band migrates image from single-contrast upper GI barium study distally into the antrum or small bowel shows barium completely surrounding band (black or proximally to the cardia, barium stud arrows), which has migrated to cardia and is Figure 22 ies may reveal high-grade obstruction causing partial obstruction with dilated, fluid-filled (Fig 20) (59), necessitating immediate esophagus (white arrows) above band. The band removal of the band. was removed surgically. (Reprinted, with permission, from reference 59.) Port- and band-related complications.—Port-related complications of laparoscopic gastric banding include in- Sleeve gastrectomy is a procedure in fections and port eversion. The band which a long, narrow gastric pouch is system can also fail if the port, tubing, created by removing about 75% of the or band becomes disconnected or if the stomach, promoting weight loss by means tubing is kinked or disrupted (49). of the restrictive effect of the pouch (10). The latter complications are readily Unlike gastric banding, there is no need detected on abdominal radiographs. for periodic adjustments with sleeve Rarely, the tubing can erode into the gastrectomy (67), but this procedure Figure 22: Normal imaging findings after sleeve lumen of the stomach, duodenum, or is irreversible. gastrectomy. Supine spot image from single-con- even the colon, causing recurrent port trast upper GI barium study shows tubular narrowing Surgical Anatomy site infections (64). This complication of gastric pouch (arrows) secondary to resection of can be diagnosed on barium studies or Sleeve gastrectomy is performed by greater curvature of proximal and mid stomach. CT scans by documenting the intralu- laparoscopically dividing the stomach Note relatively abrupt widening of gastric antrum, minal location of the tubing (64). Con- along its long axis and resecting the which is preserved. firmed intraluminal erosion of the greater curvature of the fundus, body, tubing necessitates surgical removal of and proximal antrum, producing a nar- the tubing to prevent continued infec- row, banana-shaped gastric pouch bular gastric pouch in patients with a tions (64). along the lesser curvature (Fig 21) (10). laparoscopic sleeve gastrectomy (Fig 22) The remaining stomach has a residual (67). Because the distal gastric antrum volume of only about 100 mL, causing is preserved, there may be a relatively Laparoscopic Sleeve Gastrectomy the patient to experience early satiety abrupt segment of widening at the dis- Laparoscopic sleeve gastrectomy is a and weight loss (10). tal end of the pouch. Some patients may relatively recent surgical technique in- have transient retention of barium in the troduced in 1999 (65). This procedure Normal Imaging Features proximal end of the pouch because of was estimated to account for about 5% Upper GI examination.—Upper GI loss of peristalsis during the early post- of all bariatric surgery in 2008 (66). examinations typically reveal a long, tu- operative period (68). Occasionally, a

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Figure 23 Figure 24 Figure 25

Figure 23: Normal appearance of sleeve gastrectomy at CT. Axial CT image after oral and intravenous contrast material administration show a small-caliber, tubular stomach after resection along greater curvature. Note surgical suture line (arrow). There is prominent fat attenuation in surgical bed.

Figure 25: Sleeve gastrectomy with stricture and linear outpouching or surgical placation obstruction. Supine spot image from single-contrast defect in a residual portion of nonexcised upper GI barium study shows short segment of gastric fundus can mimic the appearance marked narrowing (black arrow) in gastric pouch. of an extraluminal leak (10). Also note dilation of stomach and esophagus proxi- Abdominal CT.—CT may be performed mally. (White arrows = staple line abutting greater after laparoscopic sleeve gastrectomy to curvature.) assess for abscesses, perforation, staple line dehiscence, and other complications such as splenic injury or infarction. CT typically reveals a narrowed, tubular Figure 24: Sleeve gastrectomy with postoperative CT scans may demonstrate the site of stomach that has a smaller caliber leak. (a) Supine spot image from upper GI examina- leakage as well as localized extraluminal along its long axis. A staple line is typ- tion with water-soluble contrast material shows focal collections or abscesses in this region ically identified along the greater curva- leak (arrow) from proximal stomach laterally into (Fig 24b). ture of the residual stomach (Fig 23), extraluminal collection in left upper quadrant (C). (S Gastric strictures and gastric outlet but no Roux limb is seen when a 5 gastric sleeve.) (b) Axial CT image after oral and obstruction.—Some patients develop intravenous contrast material administration shows sleeve gastrectomy is performed as a symptoms of gastric outlet obstruction tubular stomach (S), with extraluminal collection (C) stand-alone surgical procedure. In con- when scarring along the greater curva- of gas and extravasated contrast material (arrows) in trast, a jejunal Roux limb may be visual- ture staple line causes marked narrowing left upper quadrant due to postoperative leak. ized in the left upper quadrant when a of the pouch. Barium studies may reveal sleeve gastrectomy is performed as the focal strictures or long segments of nar- restrictive component in conjunction individuals typically present with pain, rowing with delayed emptying of barium with a Roux-en-Y gastric bypass. Abun- fever, and leukocytosis. Leaks most com from the residual stomach (Fig 25). Focal dant mesenteric fat is often identified in monly occur from the proximal end of strictures may respond to endoscopic di- the expected location of the resected the staple line near the gastroesopha- lation, but longer segments of narrowing portion of the stomach (Fig 23). geal junction (69), often extending lat- occasionally necessitate surgical revision erally from the greater curvature staple or resection of the pouch. Complications line, and are usually manifested on upper Gastric dilation.—Gastric dilation is Gastric leaks.—Gastric leaks are a GI examinations by extravasation of another complication of sleeve gastrec- potential concern after laparoscopic water-soluble contrast material into ex- tomy, necessitating surgical revision of sleeve gastrectomy because of the length traluminal tracks or collections in the the pouch in about 4.5% of patients of the staple line along the greater cur- left upper quadrant (Fig 24a). If no leak (65). Affected individuals present with vature of the gastric pouch. Surprisingly, is detected with a water-soluble contrast inadequate weight loss or recurrent weight however, postoperative leaks have been agent, high-density barium should be gain. Barium studies may reveal wid- reported in less than 1% of patients administered to rule out subtle leaks ening of the gastric sleeve, which no after this form of surgery (65). Affected that might otherwise be missed (19). longer has a tubular appearance.

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Gastroesophageal reflux.—Sleeve gas 10. Shah S, Shah V, Ahmed AR, Blunt DM. Im- aroscopic gastric bypass. Endoscopy 2003; trectomy is thought to predispose to the aging in bariatric surgery: service set-up, 35(9):725–728. post-operative anatomy and complications. development of postoperative gastro- 23. Sanyal AJ, Sugerman HJ, Kellum JM, Engle Br J Radiol 2011;84(998):101–111. esophageal reflux, possibly because of KM, Wolfe L. Stomal complications of gas- the distorted gastric anatomy and stasis 11. Jha S, Levine MS, Rubesin SE, et al. Detec- tric bypass: incidence and outcome of therapy. caused by the procedure. The frequency tion of strictures on upper gastrointestinal Am J Gastroenterol 1992;87(9):1165–1169. tract radiographic examinations after lapa- of reflux symptoms 1 year after surgery 24. Rasmussen JJ, Fuller W, Ali MR. Marginal roscopic Roux-en-Y gastric bypass surgery: ulceration after laparoscopic gastric bypass: may be as high as 20% (70). Such reflux importance of projection. AJR Am J Roent- an analysis of predisposing factors in 260 can be detected on barium studies. genol 2006;186(4):1090–1093. patients. Surg Endosc 2007;21(7):1090–1094. Disclosures of Conflicts of Interest: M.S.L. Fi- 12. Carucci LR, Turner MA, Conklin RC, DeMaria 25. Dallal RM, Bailey LA. Ulcer disease after nancial activities related to the present article: EJ, Kellum JM, Sugerman HJ. Roux-en-Y gastric bypass surgery. Surg Obes Relat Dis author is a consultant to Bracco Diagnostics. Fi- gastric bypass surgery for morbid obesity: 2006;2(4):455–459. nancial activities not related to the present arti- evaluation of postoperative extraluminal leaks cle: author has received royalties for GI radiology with upper gastrointestinal series. Radiology 26. Sapala JA, Wood MH, Sapala MA, Flake texts and payments for development of educa- 2006;238(1):119–127. tional presentations (visiting professorships). 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