Imaging of Bariatric Surgery:Normal Anatomy and Postoperative Complications

Journal Club March 2014

Daniel Oppenheimer, M.D.

Marc S. Levine, MD and Laura R. Carucci, MDRadiology: Volume 270: Number 2—February 2014

Goals

• Describe the surgical anatomy and normal imaging findings for three major forms of bariatric surgery

• Identify the major complications of these forms of bariatric surgery and their relevant clinical features.

• Discuss the imaging findings of bariatric surgery complications on UGI and CT exams

Introduction

• BMI (kg/m2)– 25-29 kg/m2 = overweight– 30-35 kg/m2 = obesity– 35+ = morbid obesity

• Obesity Epidemic– USA Adults 2004: 66% overweight, 32% Obese

• 300,000+ deaths annually– 2nd only to tobacco in preventable deaths

• Bariatric Surgery increasing dramatically– 5x # procedures in 2003 vs. 1998

Bariatric Surgery Concepts

• Restrictive procedure– Decrease gastric volume early satiety– Laparoscopic adjustable gastric banding and

laparascopic sleeve gastrectomy

• Bypass procedure– Intentional malabsorption

Laparoscopic Roux-en-Y• Most popular procedure in the

USA– Highest long-term success and

greater weight loss– Malabsorptive and Restrictive

• Stomach divided– Small gastric pouch – restrictive

effect– Larger excluded stomach

• Jejunum divided– Roux (efferent) limb anastomosed

to gastric pouch proximally and jejunojejunostomy distally

– Biliopancreatic (afferent) limb anastomosed to jejunojejunostomy

http://www.utswmedicine.org

Roux-en-Y Normal Anatomy

Assessment of Roux-en-Y Bypass

• UGI:– Scout image!– Gastric pouch, gastrojejunal anastomosis, Roux limb and

jejunojejunal anastomosis• Leak, stricture, obstruction, ulcers• Excluded stomach and biliopancreatic limb not well evaluated

• CT:– Oral contrast right before exam– Contrast in gastric pouch, Roux limb to jejunojejunal

anastomosis– Excluded stomach collapsed and non-opacified– Leak, stricture, obstruction, ischemia, collections

Roux-en-Y Complications

• Leaks• Stricures• Marginal Ulcers• Jejunal ischemia• Small bowel obstruction• Recurrent weight gain

Leak

• Up to 5% of patients• ~3/4 at gastrojejunal

anastomosis• Usually <10 days post-op• Abscess, peritonitis, sepsis• H20 soluble UGI POD #1-2• Percutaneous drainage

and Abx vs. surgery

Anastomotic Stricture

• Transient edema and spasm post op

• 4+ weeks post-op• 3-9% of patients• Usually at gastrojejunal

anastomosis• Scarring vs. chronic

ischemia• Endoscopic dilatation

Chandler et. al, AJR 2008;190(1):122–135.

Marginal Ulcers

• At gastrojejunal anastomosis

• 3-13% of patients• Chronic exposure of

gastric acid to Roux limb

• Epigastric pain, UGIB• PPIs, surgical revision

Jejunal Ischemia

• Acute– Pain, bleeding, N/V early post-op– UGI: Thickened spiculated mucosal folds –

submucosal edema and hemorrhage– CT: Bowel wall thickening with mesenteric edema and

engorged mesenteric vessecls

• Chronic– Intractable N/V secondary to jejunal stricture– UGI: Smooth tubular narrowing, loss of mucosal folds,

non-healing giant ulcer(s) > 2.5 cm– CT: Jejunal narrowing with bowel wall thickening

Jejunal Ischemia

Small Bowel Obstruction

• Up to 5% of patients• Adhesions, internal hernias, abd wall hernias, strictures,

intussuception• Type A

– Dilated Roux limb, decompressed B-P limb and excluded stomach

• Type B– Dilated B-P limb and excluded stomach– Closed loop – risk ischemia, perforation

• Type C – SBO distal to jejunojejunostomy– Dilated Roux and B-P limbs

Type A SBO

Type B SBO

Recurrent Weight Gain• Dehiscence of gastric staple line• “Gastrogastric fistula”• Food enters excluded stomach• Restrictive effect gone• Patients no longer have early

satiety• Contrast in excluded stomach

– Must exclude reflux from B-P limb

• Dilation of gastrojejunal anastomasosis another cause recurrent weight gain

Laparoscopic Adjustable Gastric Banding

• Silicone band with inflatable balloon sutured around proximal stomach ~2 cm below GE jxn

• Creates small gastric pouch• Inflatable inner sleeve – sub q port in abd wall

– adjust band intermittently to alter degree of restrictive effect

• Early satiety decreased caloric intake• Less invasive vs. Roux-en-Y• Comparable (short-term) weight loss• Fewer complications

Laparoscopic Adjustable Gastric Banding

Chandler et. al, AJR 2008;190(1):122–135.

Normal Phi angle 4-58 deg

Lap Band Complications

• Stomal stenosis• Pouch dilation• Band slippage• Malpositioned Band

Stomal Stenosis

• Most common complication, 8-11%

• Band overinflation, edema• Excessive luminal narrowing,

obstruction • N/V, regurgitation, dysphagia, pain• Findings

– Excessive luminal narrowing at band, dilated of proximal stomach/esoph, GE reflux, slow emptying/lack of contrast through stoma

• Deflate band +/- repeat fluoro

Chandler et. al, AJR 2008;190(1):122–135.

Band Slippage

• 4-13%• Band overinflation, recurrent

emesis, poor surgical technique• Herniation of fundus above

band• Luminal narrowing, obstruction• Increased Phi angle, “O” sign,

air-fluid level in gastric pouch• Deflate band +/- surgical

correction

Malpositioned Band

• Inexperienced surgeon• Band placed in perigastric fat – no

restrictive effect• Band placed in lower stomach - gastric

outlet obstruction

Perforation

• <1%• Traumatic injury to gastric wall at surgery• Pain, fever, leukocytosis• UGI: Contained or free extravasation of

contrast• CT: Contrast extravasation, extraluminal

gas, fluid collections

Gastric Volvulus

• Rare• Band slippage with twisting of

stomach around band• Closed loop obstruction

– Strangulation, ischemia, infarction

• UGI: converging gastric folds, stomach rotated upwards to left above fundus, luminal obstruction

• CT: Gastric wall thickening, pneumatosis

• Urgent surgical removal

Intraluminal Band Erosion

• Late complication, <2%• Pressure necrosis from

inflated band• Usually incomplete erosion• Rarely complete erosion

– migrate distally in antrum, duodenum, or proximal jejunum or proximally to GE jxn

– mechanical obstruction

• Contrast surrounding band• Surgical removal

Port and Band-related complications

• Port infection and port eversion• Port, tubing or band kink or disruption• Tube erosion into stomach or bowel

Chandler et. al, AJR 2008;190(1):122–135.

Port and Band-related complications

Chandler et. al, AJR 2008;190(1):122–135.

Laparoscopic Sleeve Gastrectomy

• Newer technique - ~5% of bariatric surgeries in 2008

• Stomach divided along long axis

• ~75% stomach removed – Banana shaped pouch created – restrictive effect

• ~100 cc total volume• No need for periodic

adjustments• Irreversible

http://www.massgeneral.org

Kiriakopolus et. al, Hormones 2009, 8(2):138-143

Laparscopic Sleeve Gastrectomy Complications

• Gastric Leak• Gastric Stricture/Gastric outlet obstruction• Gastric Dilation• Gastroesophageal Reflux

Gastric Leak

• <1%• Long staple line along greater curvature• Most commonly at proximal end of staple

line laterally near GE jxn• Pain, fever, leukocytosis• Extravasation of contrast, extraluminal

collections/abscesses

Gastric Leak

Gastric Stricture/Gastric Outlet Obstruction

• Scarring along greater curvature staple line– Narrowing of pouch

• Focal strictures or long segment narrowing

• Delayed emptying of contrast from residual stomach

• Dilated proximal stomach and esophagus

• Endoscopic dilatation +/- surgical revision

Gastric Dilation

• ~4.5%• Inadequate weight loss, recurrent weight

gain• Widening of gastric sleeve, loss of

tubular/banana shape

Gastroesophageal Reflux

• Increased incidence of GE reflux– up to 20%– Altered gastric anatomy, stasis

• Reflux on UGI studies• Esophagitis, Barrett’s esophagus, carcinoma

Question #1

Which of the following anatomic regions usually is NOT opacified with oral contrast material on CT images after Roux-en-Y gastric bypass?

a. Gastric pouch b. *Excluded stomach c. Jejunal Roux limb d. Common small bowel channel (distal to jejunojejunostomy)

Question #2

What is the most common site of leak after Roux-en-Y gastric bypass?

a. Gastric pouch b. *Gastrojejunal anastomosis c. Blind-ending jejunal stump d. Jejunojejunal anastomosis

Question #3

Which set of findings is most likely to be associated with small bowel obstruction distal to the site of the jejunojejunostomy after Roux-en-Y gastric bypass?

a. Collapsed Roux limb and collapsed biliopancreatic limb b. Dilated Roux limb and collapsed biliopancreatic limb c. Collapsed Roux limb and dilated biliopancreatic limb d. *Dilated Roux limb and dilated biliopancreatic limb

Question #4

7. Which of the following is LEAST likely to be a sign of distal band slippage on abdominal radiographs after laparoscopic adjustable gastric banding?

a. Increased Phi angleb. Dilated gastric pouch above band c. *More vertical orientation of band than usual d. O-shaped configuration of band

Question #5

Leaks from the gastric sleeve after sleeve gastrectomy most commonly involve which of the following portions of the gastric staple line?

a. *The proximal end of the staple line laterally b. The proximal end of the staple line medially c. The distal end of the staple line laterally d. The distal end of the staple line medially

References

• Chandler RC, Srinivas G, Chintapalli KN, Schwesinger WH, Prasad SR. Imaging in bariatric surgery: a guide to postsurgical anatomy and common complications. AJR Am J Roentgenol 2008;190(1):122–135.

• Kiriakopoulos A, Varounis C, Tsakayannis D, Linos D. Laparoscopic sleeve gastrectomy in morbidly obese patients. Technique and short term results. Hormones (Athens) 2009; 8: 138-43.

• http://www.massgeneral.org• http://www.utswmedicine.org

Thank You Dr. Sidhu