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Gastrointestinal Complications of Laparoscopic Roux-en-Y Gastric Bypass Surgery in Patients Who Are Morbidly Obese: Findings on Radiography and CT

¹ Department of Radiology, Division of Abdominal Imaging, University of Pittsburgh Medical Center, 200 Lothrop St., Pittsburgh, PA 15213.
² Present address: Department of Radiology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.

Received March 12, 2002; accepted after revision June 23, 2002.

 
Address correspondence to M. P. Federle.

Introduction

Top Introduction Imaging of Complications of... Summary References

 
The incidence of overweight American adults is increasing; it is estimated that 6% of women and 2% of men in the United States are morbidly obese [1]. Morbid obesity is defined as a body mass index of 35 kg/m² or 40 kg/m² with and without comorbidity, respectively, which roughly equals to 100 lb (45 kg) over the ideal body weight [2]. Severe obesity is associated with a large number of morbidities and with early mortality. Results of nonsurgical treatments for obesity have been disappointing, and bariatric surgery is the only reliable method of weight reduction that allows significant weight loss, extended weight maintenance, and control or reversal of some obesity-related health problems [3].

Many bariatric procedures involving the restriction of gastric capacity, induced malabsorption, or both have been advocated over the last few decades [4,5,6,7]. The laparoscopic approach to bariatric surgery has decreased recovery time and reduced the number of complications. In laparoscopic Roux-en-Y gastric bypass surgery, a 15-30 mL gastric pouch is created and is anastomosed end-to-side to a Roux limb (Fig. 1A,1B). To create the Roux limb, the surgeon transects the jejunum at approximately 30 cm from the ligament of Treitz. The Roux limb is measured 75 cm distally, or 150 cm distally for the massively obese patient, and a stapled side-to-side anastomosis is created with the proximal jejunal limb. The enterotomy sites are stapled closed, and the mesenteric defects of the jejunum and transverse colon are sutured closed. The Roux limb can be brought to the pouch through or anterior relative to the transverse mesocolon and is either ante- or retrogastric.

View larger version (66K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1A. —Drawings of anatomy after Roux-en-Y gastric bypass surgery shows gastric pouch, excluded stomach, Roux loop, and distal jejunojejunal anastomosis (solid arrow). (Adapted with permission from [3]) In this illustration, Roux loop (R) has been passed through surgical defect in transverse mesocolon (open arrow) to lie in retrocolic retrogastric location. Sutures are used to close mesenteric defect. GP = gastric pouch, ST = excluded stomach.

View larger version (74K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1B. —Drawings of anatomy after Roux-en-Y gastric bypass surgery shows gastric pouch, excluded stomach, Roux loop, and distal jejunojejunal anastomosis (solid arrow). (Adapted with permission from [3]) In this modified illustration, no defect is created in mesocolon. Roux limb is antecolic and antegastric.

Roux-en-Y gastric bypass surgery is associated more often with sustained weight loss than other types of bariatric procedures [3] and has become the procedure of choice for the management of morbid obesity in the United States [5]. The purpose of this pictorial essay is to familiarize radiologists with the imaging findings of the gastrointestinal complications that are associated with Roux-en-Y gastric bypass surgery.

Imaging of Complications of Roux-en-Y Gastric Bypass Surgery

Top Introduction Imaging of Complications of... Summary References

 
Upper gastrointestinal radiography and CT are useful in depicting the normal anatomy after gastric bypass surgery and are complementary in detecting complications after surgery, thus allowing early diagnosis and treatment [4]. An upper gastrointestinal series with water-soluble contrast medium is usually performed within 24 hr after surgery as part of the routine follow-up (Fig. 2). If no gastrointestinal extravasation of water-soluble contrast medium is noted, barium may be given subsequently for better delineation of bowel anatomy.

View larger version (132K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 2. —44-year-old woman 24 hr after uncomplicated gastric bypass surgery. Upper gastrointestinal radiograph shows contrast material entering small gastric pouch (GP) and Roux loop (R) including "blind" end (R') to left of anastomosis. Note unopacified surgical drain (arrow).

CT is performed when an anastomotic leak is diagnosed on radiography, when an intraabdominal abscess is suspected, and when a small-bowel obstruction is suspected.

Gastrointestinal complications after gastric bypass surgery are classified into major complications that are life-threatening or that require intervention and minor complications that resolve spontaneously. Major complications include small-bowel obstruction, large anastomotic leaks and strictures, and gastrogastric and gastroenteric fistulas. Minor complications include small leaks, marginal ulcers, pancreatitis, esophagitis, and cholelithiasis.

Anastomotic Leaks
Enteric content leak is a serious complication that may result in sepsis and even death if diagnosis and treatment are delayed. The incidence of leaks after laparoscopic Roux-en-Y bypass surgery is 1-6% [3,4,5,6,7,8,9]. Patients may present with only tachycardia and abdominal discomfort, with no signs of peritonitis or fever; performing a physical examination is difficult, and the findings may be misleading because of the patient's size. Leaks usually occur within the first 10 days of surgery, most commonly at the gastrojejunal anastomosis and less commonly at the distal Roux anastomosis.

CT and upper gastrointestinal radiographic series are reliable in revealing leaks: contrast material spills into the peritoneal cavity (Fig. 3,4,5A,5B,6,7A,7B,8A,8B) and fills the surgical drains that are often placed adjacent to the anastomosis at surgery (Fig. 4). Contrast material that refluxes up the proximal jejunum and duodenum into the distal excluded stomach may simulate a leak (Fig. 9). Even small leaks may result in a fluid collection or fistulous tract formation. If a leak seals off after a fluid collection has formed, neither may be evident on radiography after the administration of oral contrast medium (Fig. 10A,10B).

View larger version (109K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 3. —42-year-old woman 1 day after bypass surgery with small leak that resolved spontaneously in 10 days. Upper gastrointestinal radiograph shows extravasation of small amount of contrast medium (straight arrow) from gastrojejunal anastomosis. Note opacification of surgical drain (curved arrow). R = Roux loop, GP = gastric pouch.

View larger version (116K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 4. —37-year-old woman 1 day after bypass surgery with small leak that required surgical repair. Upper gastrointestinal radiograph shows minimal pocket of extravasated contrast medium (open arrow) originating from gastric pouch (GP) or anastomosis with definite opacification of surgical drain (solid arrow).

View larger version (112K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 5A. —42-year-old woman with abdominal pain and fever 4 days after bypass surgery. Imaging revealed large leak from gastrointestinal anastomosis that required surgical treatment. Upper gastrointestinal radiograph shows extravasation of contrast medium (solid arrows) from anastomosis (open arrow). R = Roux loop, GP = gastric pouch.

View larger version (161K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 5B. —42-year-old woman with abdominal pain and fever 4 days after bypass surgery. Imaging revealed large leak from gastrointestinal anastomosis that required surgical treatment. Contrast-enhanced transverse CT scan reveals enteric contrast material extravasating (arrows) from gastric pouch (GP) and surrounding spleen.

View larger version (154K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 6. —61-year-old woman with abdominal pain 1 day after bypass surgery. Transverse unenhanced CT scan shows distal excluded stomach (ST), barium-filled small-bowel loop, and extraluminal contrast material outlining inferior liver border (solid arrows) and peritoneum (open arrow).

View larger version (146K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 7A. —32-year-old woman with fever and abdominal pain 10 days after bypass surgery. Imaging showed large gastrojejunal anastomotic leak and abscess. Abscess was drained with CT guidance. Upper gastrointestinal radiograph shows extravasation of contrast material (solid arrows) from gastrojejunal anastomosis with large amount of loculated extraluminal air (open arrow) adjacent to it. R = Roux loop, GP = gastric pouch.

View larger version (164K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 7B. —32-year-old woman with fever and abdominal pain 10 days after bypass surgery. Imaging showed large gastrojejunal anastomotic leak and abscess. Abscess was drained with CT guidance. Unenhanced transverse CT scan shows contrast material in gastric pouch (GP) and large abscess (Ab) of lesser sac with small amount of contrast material lining its border (arrow).

View larger version (140K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 8A. —60-year-old woman with abdominal pain and fever 18 days after bypass surgery. Small leak and fluid collection were seen on imaging. Both resolved spontaneously within 6 days. Upper gastrointestinal radiograph depicts contrast extravasation (arrow) from gastric pouch (GP) and formation of fluid collection containing air—fluid—contrast level (C). R = Roux loop.

View larger version (144K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 8B. —60-year-old woman with abdominal pain and fever 18 days after bypass surgery. Small leak and fluid collection were seen on imaging. Both resolved spontaneously within 6 days. Transverse contrast-enhanced CT scan shows gastrojejunal anastomotic staple line (curved arrow) with adjacent fluid collection containing air—fluid level (straight arrow). ST = distal excluded stomach.

View larger version (130K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 9. —45-year-old woman 1 day after uncomplicated bypass surgery. Oral contrast medium that refluxed up proximal jejunum into bypassed stomach (arrows) simulates leak. Only by positioning patient and observing flow of contrast material within stomach and duodenum could this complication be identified correctly. R = Roux loop, GP = gastric pouch.

View larger version (119K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 10A. —52-year-old woman with abdominal pain and fever 4 days after bypass surgery. Intraabdominal abscess was detected at imaging. Upper gastrointestinal radiograph shows normal passage of contrast material through gastric pouch and gastrojejunal anastomosis. Air—fluid level (arrow) is seen lateral to gastric pouch (GP) with no evident extravasation of contrast material. R = Roux loop.

View larger version (155K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 10B. —52-year-old woman with abdominal pain and fever 4 days after bypass surgery. Intraabdominal abscess was detected at imaging. Unenhanced transverse CT scan shows large fluid collection (Ab) adjacent to gastrojejunal anastomosis (arrowhead). Only by following anatomy on sequential images (not shown) could abscess be distinguished from excluded stomach.

Fluid collections are most commonly located in the left upper quadrant, especially in the perisplenic area, and may evolve into abscesses. The collections are often loculated with a contrast-enhancing rim and gas suspended in or above the fluid (Figs. 6,7A,7B,8A,8B and 10A,10B). CT plays an important role in the diagnosis of leaks and fluid collections and can be used to guide placement of a drainage catheter, obviating surgery in many cases [3] (Fig. 11A,11B).

View larger version (164K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 11A. —59-year-old man with pain and fever 2 weeks after bypass surgery. Multiple abscesses, caused by leak, were successfully drained using percutaneous catheters. Unenhanced CT scan shows perihepatic fluid collection (Ab) containing air—fluid level. Second smaller collection (curved arrow) can be seen adjacent to gastrojejunal anastomosis (straight arrow).

View larger version (184K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 11B. —59-year-old man with pain and fever 2 weeks after bypass surgery. Multiple abscesses, caused by leak, were successfully drained using percutaneous catheters. CT scan was obtained while large perihepatic collection was being drained, thus obviating surgery, with pigtail catheter (white arrow), which was placed using CT guidance. Second collection (C) is larger and was also drained using CT guidance (not shown). Black arrow indicates free intraperitoneal air.

Anastomotic Stricture
Stenosis of the gastric pouch outlet after laparoscopic bypass surgery is reported in as many as 27% of patients [3,4,5,6,7,8,9]. Patients present with dysphagia, vomiting, dehydration, and excessive weight loss. Diagnosis is most commonly made with endoscopy that also allows treatment (dilatation). Contrast-enhanced radiography depicts the delay in the passage of contrast material through the anastomosis as well as the degree of the anastomotic stricture. A spherical shape of the pouch and air—fluid—contrast material levels are common features on radiography (Fig. 12). Endoscopic balloon dilatation is usually successful. Stenosis at the jejunojejunal anastomosis is rare (0.9%) and is amenable only to surgical correction.

View larger version (94K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 12. —35-year-old woman with dysphagia and retching 2 months after bypass surgery. Upper gastrointestinal radiograph shows stricture (arrow) at gastrojejunal anastomosis with markedly dilated spherical gastric pouch (GP) but with passage of contrast material into Roux loop (R). Stricture was managed successfully with endoscopic balloon dilatation. E = esophagus.

Small-Bowel Obstruction
Small-bowel obstruction after laparoscopic bypass surgery is reported in 4-5% [3,4,5,6,7,8,9] of patients and is usually caused by internal hernias or adhesions, although bezoar formation in the gastric pouch and intussusception have also been documented [3, 4]. The laparoscopic approach has reduced the prevalence of adhesions but has led to an increase in the prevalence of internal hernia formation, which was rarely seen with "open" procedures. Adhesions are more common during the first month after surgery, whereas internal hernias usually develop later.

Noting the prevalence of transmesenteric internal hernias among patients who had the Roux limb placed through the transverse mesocolon, our surgeons now place the Roux limb in an antecolic position. This strategy seems to have decreased the prevalence of internal hernias.

There are three potential locations for internal hernias: the opening in the transverse mesocolon through which the Roux limb is brought to the gastric pouch (most common type), the small-bowel mesenteric defect at the jejunojejunostomy site, and the space behind the Roux limb (Peterson type). The herniated bowel is usually the Roux limb itself with a varying amount of additional small-bowel loops [3]. There is a risk for volvulus of the herniated small bowel with resultant ischemia.

On upper gastrointestinal radiography, a cluster of small-bowel loops is often seen in the left upper or mid abdomen. The cluster is relatively fixed, remaining high on erect radiographs and revealing stasis and delay in passage of contrast material [3] (Fig. 13). The CT appearance of internal hernias depends on their location, although clustering of dilated small-bowel loops and crowding and congestion of the mesenteric vessels are seen in all cases [3] (Figs. 14A,14B and 15). In cases of herniation through the transverse mesocolon, the herniated cluster of bowel is located posterior relative to the stomach and may exert mass effect on its posterior wall (Fig. 14A,14B). In herniations through the small-bowel mesentery, the clustered bowel is pressed against the abdominal wall with no overlying omental fat, causing central displacement of the colon [3] (Fig. 15). The Peterson-type hernia is difficult to diagnose because it has neither a confining sac nor a characteristic location, and the only clues to its presence may be engorgement and crowding of the mesenteric vessels and evidence of small-bowel obstruction.

View larger version (100K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 13. —50-year-old woman with abdominal pain and distention 3 days after bypass surgery. Upper gastrointestinal radiograph shows cluster of dilated small-bowel loops in left upper abdomen (arrowheads). Large internal hernia through transverse mesocolon that was causing small-bowel obstruction was found at surgery.

View larger version (137K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 14A. —41-year-old woman with abdominal pain and distention 34 days after bypass surgery. Bowel obstruction caused by transmesenteric internal hernia was detected on CT. Unenhanced CT scan shows dilated Roux loop (R) posterior relative to distal excluded stomach (ST). P = pancreatic head.

View larger version (130K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 14B. —41-year-old woman with abdominal pain and distention 34 days after bypass surgery. Bowel obstruction caused by transmesenteric internal hernia was detected on CT. CT scan obtained more caudal than A shows herniated small-bowel cluster (SB) and engorged mesenteric vessels (arrows).

View larger version (105K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 15. —46-year-old woman with pain and distention 18 months after bypass surgery. Transverse CT scan shows cluster of mildly dilated small-bowel segments (S) adjacent to left abdominal wall anterior to jejunojejunal anastomosis (curved arrow) with engorgement and crowding of mesenteric vessels (straight arrow). Internal hernia through small-bowel mesentery was diagnosis. More caudal section (not shown) revealed no omental fat between small-bowel cluster and abdominal wall.

Other Less Common Complications
Obstruction and perforation of the distal stomach were fatal complications associated with the older gastric bypass surgical procedures but are rarely seen with laparoscopic Roux-en-Y bypass surgery. If obstructed, the distal stomach may dilate markedly and if a perforation occurs, free intraperitoneal air is seen (Fig. 16). Gastrogastric and gastrocutaneous fistulas may develop rarely, especially in cases with leakage of enteric contents, and usually require surgical repair. Marginal ulcers are uncommon with Roux-en-Y bypass surgery with a reported rate of 0.5-1.4% of patients [3, 4, 9]. These ulcers are the result of exposure of the gastrojejunal anastomosis to gastric acid and respond well to medical treatment.

View larger version (135K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 16. —54-year-old woman with abdominal pain 9 days after bypass surgery. Unenhanced CT scan shows free intraperitoneal air (arrows) and markedly dilated distal stomach (ST). Perforation of distal stomach was repaired laparoscopically.

Incisional and ventral hernias and infection of an abdominal wall wound, which were frequent and serious complications in "open" procedures, are uncommon with the laparoscopic approach.

Summary

Top Introduction Imaging of Complications of... Summary References

 
Radiologists play an important role in the diagnosis of gastrointestinal complications of Roux-en-Y gastric bypass surgery, especially given the nonspecific clinical presentation of some of these complications. CT and upper gastrointestinal radiography are complementary in the evaluation of these complications, allowing early treatment.

References

Top Introduction Imaging of Complications of... Summary References

 

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This Article Figures Only Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Blachar, A. Articles by Federle, M. P. Search for Related Content PubMed PubMed Citation Articles by Blachar, A. Articles by Federle, M. P. Social Bookmarking                      What's this?