MDCT Evaluation of Early and Late Post-operative Complications of Roux en y Gastric Bypass Surgery and Vertical Sleeve Gastrectomy

Disclosures

Goals/Objectives

Surgeries

CT Protocol

RYGB Procedure

1. Creation of Gastric Pouch (P)
2. Divide jejunum 25-50cm distal to ligament of Treitz
   • Excluded stomach to this point forms biliopancreatic limb (BP)
3. From division, 75-100 cm measured distally to form roux limb (R).
4. Jejunojejunostomy (J-J) formed by side –to-side anastomosis
5. Roux limb pulled up to form gastrojejunostomy (G-J)
6. Common channel distal to J-J

Illustration by Emily Meltzer, DMD

RYGB Procedure

Gastrojejunostomy

• Antecolic vs. Retrocolic
• Laparoscopic RYGB more commonly antecolic
• Patient factors
  • Thick, fatty small bowel mesentery may not be amenable to antecolic, which requires pulling roux limb up longer distance

Diagrams in sagittal projection showing antecolic G-J (A) and retrocolic G-J (B) P: gastric pouch; R: roux limb; G-J: gastrojejunostomy



Illustration by Emily Meltzer, DMD

Approach to CT Interpretation

Early Complications (< 2 weeks)

Anastomotic Leak

• Most commonly occurs at G-J anastomosis
  • Report incidence 1-5.6%
• Serious complication
  • Leak related mortality has been reported as high as 50%
• Fluoroscopy typically initial study
  • MDCT useful for problem solving and evaluation for abscess

Axial CT image shows large subdiaphragmatic abscess (red arrows) secondary to leak from gastric pouch anastomosis (blue arrow)

Early Small Bowel Obstruction

Early Small Bowel Obstruction

Mesenteric Hematoma Post RYGB

Sagittal CT image (A) and axial CT image (B) show large mesenteric hematoma (red arrows) in left hemi-abdomen 24 hours post RYGB. Hematoma is seen just inferior to G-J anastomosis (blue arrow).

Late Complications (>2 weeks)

Late Small Bowel Obstruction

Transmesentric Internal Hernia

Internal Hernia

Most common sites for herniation

• J-J small bowel mesenteric defect (Transmesenteric)
• Petersen Hernia: space between roux limb, transverse mesocolon and jejunal mesentery
• Transmesocolic
  • Only possible with retrocolic GJ

Common sites of internal hernia post RYGB. P – Pouch, R – Roux, G-J – gastrojejunostomy, J-J- jejunojejunostomy



Illustration by Emily Meltzer, DMD

Internal Hernia

CT Findings

• Mesenteric Swirl (A)
  • Most sensitive sign, should be reported if seen!
• Mushroom sign (B)
  • Refers to shape of bowel mesentery protruding through defect
• Others:
  • Clustered bowel loops
  • SBO otherwise unexplained
  • Change in position bowel (i.e. J-J anastomosis)

Internal Hernia

• RYGB patient with chronic, intermittent abdominal pain
• Axial MIP’s from CT in 2007 and 2014
  • J-J anastomosis (red arrows) flips from left abdomen to right
  • Indirect sign of internal hernia
    • Confirmed at Laparoscopy
  • Important: J-J is almost always normally in left mid/lower abdomen

Perforated G-J Marginal Ulcer

Remote RYGB patient with severe abdominal pain. Axial CT Image shows free air in Abdomen (red arrows), with focal perforation (yellow arrow) adjacent to G-J anastomosis suture line (blue arrow). Findings confirmed at Laparoscopy.

Companion Case – G-J Ulcer

Axial CT image (A) and Coronal CT image (B) show subtle inflammatory stranding (yellow arrows) adjacent to roux limb of RYGB (red arrows), just distal to G-J anastomosis. Upper endoscopy showed deep marginal ulcer at this site.

Marginal Ulcers

• Incidence reported as high as 16%
• Most common at G-J anastomosis
  • May lead to fistula or perforation over time
• Causes:
  • Poor perfusion/ischemia at anastomosis
  • Gastric acid exposure to jejunum
  • H. Pylori
  • Foreign material such as suture/staples

Gastrogastric Fistula

Patient post remote RYGB. Axial Images from CT show excluded stomach (blue arrows) distended with wall thickening and hyperemia. High density contrast is seen layering in excluded stomach (yellow arrow) with a small focus of intraluminal air. No contrast in BP limb. Findings reflect gastrogastric fistula, confirmed at endoscopy.

Gastrogastric Fistula

• Oral contrast seen in excluded stomach in A (red arrow)
  • G-G fistula confirmed at endoscopy
• Study 3 weeks earlier (B) without oral contrast shows moderate air in exclude stomach (blue arrow)
• Air occasionally seen in excluded stomach
  • Most commonly from reflux up BP
  • Can also be secondary to G-G fistula, especially if no air seen in BP limb

Gastrogastric Fistula

• Large tract connecting gastric pouch and excluded stomach (yellow arrow)
• Be careful, sometimes reversed RYGB can look similar!

Gastric Pouch Dilatation

Gastric Pouch Dilatation

• Gastric pouch normally has volume of 25-30 cc
• Pouch can enlarge over time due to excessive food intake
• Implicated in recurrent weight gain
• Others causes of weight gain:
  • G-G fistula
  • Enlargement of G-J anastomosis orifice

Vertical Sleeve Gastrectomy (VSG)

• Remove greater curvature of stomach from angle of His to antrum
• “Sleeve” created by staple closure of stomach around bougie
  • Bougie typically 32-60 Fr
• Results in tubular stomach configuration
• Restrictive weight loss
  • Also favorable hormonal changes
    • Decreased ghrelin which is predominantly secreted at gastric fundus

Illustration by Emily Meltzer, DMD

Complications - VSG

Anastomotic Leak

Post-op day 2 with abdominal pain and fevers. Axial image from CT without oral contrast (Fig A) shows subtle fluid collection with suggestion of internal air at anteromedial margin of spleen (red arrow) suspicious for leak. Axial MIP from repeat CT with oral contrast shows leakage of contrast into this collection (blue arrows) which is outside stomach defined by surgical suture line (yellow arrows).

Anastomotic Leak

• Increased risk following VSG compared to RYGB, up to 7%
  • Longer staple line
• Most common site is angle of His
  • Relatively decreased regional perfusion increases risk of ischemia
  • Gastric wall thinner in this region
• Very early leak may undergo re-operative repair
  • Otherwise percutaneous management with drain

Axial CT image shows extraluminal air and fluid collection secondary to leak from gastric staple line (yellow arrow) at angle of His

Trocar/Port site Hernia SBO

Take Home Points

References