Imaging of Bariatric Surgery

 Complications: Less common and less varied


image May be too tight or too loose

image May erode into stomach or esophagus


• Sleeve gastrectomy (gastric sleeve)
image 75% of stomach is removed by dividing stomach along its long axis
– Complications: Less or comparable to LAGB, less than Roux-en-Y gastric bypass (RYGB)

– Leak: Early complication seen in < 1%

– Stricture in mid stomach (transient or persistent)

• RYGB  procedure
image Gastrointestinal complications occur in ∼ 10%

image Anastomotic stricture
– Dilatation of gastric pouch, spherical shape, air-fluid-contrast material levels, delayed emptying

image Anastomotic leaks
– Most commonly at gastrojejunal anastomosis

– CT may demonstrate major and minor leaks; fluid collections not evident on upper GI series

image Marginal ulcers; rate of 0.5-1.4% after RYGB
– Usually result of ischemia

image Small bowel obstruction (SBO)
– Most common etiology: Internal hernias (IH) and adhesions

– IH: CT appearance depends on location

– Clustering of SB loops; congestion, crowding, twisting of mesenteric vessels

image Obstruction of excluded stomach and biliopancreatic limb
– Cannot be diagnosed with upper GI series; CT is key

– May progress to perforation (often fatal)

• CT and upper GI radiography have complementary roles



image
(Left) Graphic depicts the gastric banding procedure in which a silicone band is looped around the proximal stomach. A tube connects the inflatable liner of the band to a subcutaneously placed port image that can be accessed and inflated or deflated with injections of fluid.


image
(Right) Spot film from an esophagram shows the gastric band image in its expected position with a “Phi” angle of ∼ 45° (normal). The dilated, slowly emptying esophagus image indicates that the band is too tight and fluid will be removed from the access port image.

image
(Left) Radiograph shows an abnormal position of the gastric band image, which has slipped inferiorly and rotated clockwise. The connecting tubing image has also migrated into a more rightward position than expected.


image
(Right) An upright film from an esophagram in the same patient shows dilation of a larger than expected portion of the proximal stomach image with air-fluid-contrast levels, indicating stasis. Slip and rotation of the band often result in obstruction and require revision.


TERMINOLOGY


Definitions




• Imaging techniques and findings used to evaluate possible complications of surgical procedures meant to induce weight loss


IMAGING


General Features




• Morphology
image Laparoscopic adjustable gastric banding (LAGB) procedure
– Silicone band with inflatable cuff is looped around fundus, 2-3 cm below gastroesophageal (GE) junction

– Opening (stoma) is adjustable by accessing subcutaneous port connected to inflatable cuff
image Fluid is injected into or removed from port to inflate or deflate cuff

– Complications: Less common and less varied than in laparoscopic R oux-en- Y g astric b ypass (RYGB) procedure

– May be too tight (→ nausea, dehydration, excessive weight loss) or too loose (→ insufficient restriction of food intake)

– Twisting or displacement of band  (4-13% of patients)
image Should lie at a “phi” angle (between vertical line and horizontal axis of band) between 30 and 60 degrees

image May slip down and twist, partially obstructing gastric lumen through band

image Signs of slip: Phi angle > 60 degrees
image Distended stomach above band with slow emptying (air-fluid levels)

image “O” sign: On frontal image, gastric band is en face seen as an “O” rather than seen in profile

– May erode into stomach (1-14% of patients)
image Partial erosion: May have  nonspecific symptoms
image Oral contrast coats intragastric band; may not extravasate beyond stomach

image Complete erosion: May see intraperitoneal spill of contrast medium (CT or upper GI)

– Leak from stomach may occur even without erosion of band into stomach (early complication)

image Sleeve gastrectomy (gastric sleeve)
– 75% of stomach is removed by dividing stomach along its long axis
image Removes the greater curvature portion of fundus, body, and proximal antrum

image Remaining stomach only holds volume of ∼ 100 mL

– Complications: Less or comparable to LAGB, less than RYGB
image Leak: Early complication seen in < 1%
image Usually along proximal end of staple line

image Extends laterally from greater curvature

image Stricture: Early or late complication
image Focal narrowing in mid gastric pouch, at end of staple line

image May be transient or require stent or revision

image Gastroesophageal reflux (in 20% of patients)

image Laparoscopic Roux-en-Y gastric bypass procedure (RYGB)
– Surgeon divides stomach into small (∼ 30 mL) gastric pouch (parts of cardia and fundus) and much larger excluded stomach

– Excluded stomach empties into duodenum as usual, now referred to as biliopancreatic limb

– Pouch is anastomosed to roux limb of jejunum (alimentary limb) that is 75-150 cm long
image Roux limb is usually placed in antegastric and antecolic location

– Roux (alimentary) and biliopancreatic limbs are joined side-to-side (J-J anastomosis)

– Normal post-op upper GI study
image Usually performed within 48 hours of surgery to exclude leak or obstruction

image Esophagus and pouch should empty rapidly into roux limb

image Blind end of roux limb should not be mistaken for leak or ulcer

image Enteric contrast usually opacifies intestine to and beyond jejunojejunal (J-J) anastomosis
image Helps to exclude stricture at or near J-J anastomosis

– Complications: More varied and common than with other bariatric procedures
image Spasm or stricture at pouch-enteric anastomosis
image Early (spasm) or late (stricture) complication

image Recognized by dilated pouch with air-fluid level and slow emptying

image Fairly common but may resolve or respond to balloon dilation

– Leak: Usually at pouch-enteric anastomosis (up to 5% of cases)
image Early (within 10 days) complication

image Detected with upper GI or CT (complementary) by extravasation of water-soluble contrast medium

image May be contained; look for opacification of surgical drain lumen

image May extend into larger spaces, usually left subphrenic and around spleen

– Marginal ulcer
image Reported in 3-10% (more common after revision of prior gastric surgery)

image May result from reflux of acid up roux limb or ischemic injury

image Usually appears as fixed collection of barium with adjacent fold thickening

image Near pouch-enteric anastomosis

– Gastro-gastric fistula
image Opening of staple line meant to divide gastric pouch from excluded stomach

image Evident by orally administered contrast material entering excluded stomach

image May account for failure to lose expected weight, but this is relatively rare complication

– Small bowel obstruction (affects 5-10% of RYGB patients)
image Any site of obstruction may be due to adhesions or internal hernia

image Think “ABC”

image “A” = Alimentary (roux) limb is dilated
image Often down to near J-J anastomosis

image “B” = biliopancreatic limb (excluded stomach, duodenum, and proximal jejunum)
–  
image This is a closed loop obstruction and will not be detected by upper GI series (CT is essential)

image Risk of perforation of stomach or duodenum; usually constitutes surgical emergency

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Nov 16, 2016 | Posted by in GASTROINTESTINAL IMAGING | Comments Off on Imaging of Bariatric Surgery

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