Bariatric Surgery

Michael P. Federle, MD, FACR

Key Facts

Imaging

Laparoscopic adjustable gastric banding (LAGB) procedure (a.k.a. “lap band”)
- Complications: Less common and less varied
- May be too tight or too loose
- May erode into stomach or esophagus
- → leak of contrast material on UGI or CT
Laparoscopic Roux-en-Y gastric bypass procedure; bariatric procedure of choice in North America
- Gastrointestinal complications occur in about 10%
Anastomotic leaks
- Most commonly at gastrojejunal anastomosis
- CT may demonstrate major and minor leaks; fluid collections not evident on UGI series
- 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
Anastomotic stricture
- Dilatation of gastric pouch; spherical shape; air-fluid-contrast material levels
- Usually responds to balloon dilation
Obstruction and perforation of distal stomach
- Cannot be diagnosed with UGI series; CT is key
- May progress to perforation (often fatal)
Marginal ulcers; rate of 0.5-1.4% after RYGB
- Usually result of ischemia
CT and UGI radiography; complementary roles

Top Differential Diagnoses

Ileus
Reflux into excluded stomach

(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

that can be accessed and inflated or deflated with injections of fluid. (Right) Upper GI series shows a leak

of gas and contrast medium following placement of a gastric band

around the gastric fundus.

(Left) Graphic shows the typical procedure for a Rouxen-Y gastric bypass procedure, with a small gastric pouch anastomosed to a Roux limb that is 75-150 cm long, and which is anastomosed side-to-side with the “biliopancreatic” limb about 35-45 cm beyond the ligament of Treitz. (Right) RYGB procedure. Upper GI series shows minor anastomotic leak, evident only as opacification of the surgical drain

that was placed near the gastric pouch

; the “pouch-enteric” anastomosis is noted

TERMINOLOGY

Definitions

Complications of surgical procedures meant to induce weight loss

IMAGING

General Features

Morphology
- Laparoscopic adjustable gastric banding (LAGB) procedure (a.k.a. “lap band”)
  - Silicone band with inflatable cuff is looped around fundus, about 3 cm below GE junction
  - Opening (stoma) is adjustable by accessing subcutaneous port connected to inflatable cuff
    - Fluid is injected into or removed from port to inflate or deflate cuff
  - Complications: Less common and less varied than in laparoscopic Roux-en-Y gastric bypass (RYGB) procedure
  - Twisting or displacement of band
    - Should lie at an angle; cephalic side at about 1-2 o’clock position; caudal at about 7-8 o’clock
    - May slip down, leaving excessively large pouch, or slip up, leaving excessively small pouch
  - May be too tight (→ nausea, dehydration, excessive weight loss) or too loose (→ insufficient restriction of food intake)
  - May erode into stomach or esophagus
    - Leads to leak of contrast material on UGI or CT
Laparoscopic Roux-en-Y gastric bypass procedure; bariatric procedure of choice in North America
RYGB procedure
- Gastric pouch: 15-30 mL; excluded from distal stomach
  - Anastomosed end to side to Roux-en-Y limb
  - Distal gastric remnant (excluded stomach) left in its normal anatomic position
- Roux-en-Y limb; created by transection of jejunum at 35-45 cm distal to ligament of Treitz
  - Roux limb is 75-150 cm long
  - Anastomosed side-to-side with proximal jejunum
- Roux limb may be brought through transverse mesocolon to be placed in retrocolic position
  - Or anterior to transverse colon (and stomach)