Small Intestine: Bowel Resection & Anastomosis

General Principles

• Strength Layer of Bowel: Submucosa
  • All Layers Help
  • Strongest – Esophagus Mucosa Squamous Cell Layer
• Center Side Reconstructions On:
  • Small Bowel: Antimesenteric Border (High Risk for Ischemia if Elsewhere)
  • Large Bowel: Taenia Coli (Adds Strength)
• Anastomosis Weakest Time Point: 3-5 Days (Breakdown Exceeds Production)
  • Increased Collagenase Compared to Skin

Type of Anastomosis

• End-to-End
  • The End of One Loop is Anastomosed to the End of Another Loop
  • More Physiologic in Replication of Normal Gut Motility
• End-to-Side
  • The End of One Loop is Anastomosed to the Side of Another Loop
  • Considered When There is a Size Mismatch (Small Bowel to Colon) Although Others are Still Possible
• Side-to-Side
  • Bowel Loops are Oriented Side-to-Side in an Overlapping Fashion
  • Most Common when Using a Linear Stapler
  • Types:
    • Isoperistaltic: Ends are Approximated to Maintain Similar Directions of Peristalsis
      • Technically More Difficult
    • Antiperistaltic: Ends are Approximated with Opposite Directions of Peristalsis
      • Technically Less Difficult
      • Often Referred to as “Functional End-to-End”

Method

• Hand-Sewn
  • Excise Staple Lines if Present
  • Use a Stay Suture to Approximate Both Bowel Ends
  • Create Anastomosis with Full-Thickness Bites Using Absorbable Suture – Techniques are Varied (Interrupted vs Running/Direction of Travel)
  • Consider Seromuscular Lembert Sutures to Buttress as a Second Layer
  • Close the Mesenteric Defect
• Stapled
  • Traditional Method:
    • Resect Proximal & Distal Ends
    • Sharply Excise the Antimesenteric Corner of the Resected Ends
    • Place the Two Jaws of the Linear Stapler Through Each Opening
    • Arrange the Jaws Along the Antimesenteric Border
    • Assemble & Fire the Stapler to Create a Common Channel
    • Consider Placing a Reinforcing Silk Stitch (“Crotch Stich”) at the Inner Junction – The Site of Most Tension
    • Close the Enterotomies – Either with Suture or With Another Staple Load
    • Close the Mesenteric Defect
  • Barcelona Technique (For Ileostomy Reversal):
    • Approximate Proximal & Distal Ends (Prior to Resection)
    • Make Small Enterotomies at the Ends
    • Pass Stapler into Both Ends to Create Common Channel
    • Use Another Stapler to Amputate the Specimen
    • *Benefits: Cost-Effective & Only Uses Two Staple Loads (Traditional Uses 4 Staple Loads)

Comparison

• No Significant Difference in Outcomes Between Techniques
• No Difference Between Single-Layer vs Double-Layer Hand-Sewn Anastomoses
• No Difference Between Hand-Sewn & Stapled Anastomoses
  • Possibly Higher Incidence of Radiographic Leaks When Hand-Sewn (12.2% vs 4.1%) But Not Clinical Leaks (3.2% vs 4.7%)
  • Conflicting Data on Ileocolic Anastomoses (Specifically)

Intraoperative Assessment of Anastomosis Viability

• Colorectal Anastomosis Can be Endoscopically Evaluated by an Air-Leak Test
• Assessment of Perfusion;
  • Historical Subjective Findings:
    • Bowel Color
    • Observed Pulsatile Flow at the Cut Section
  • Modern Objective Findings:
    • Indocyanine Green Fluorescence Angiography (ICG-FA/ICGA) – Best Studied
    • Doppler US – Minimal Data
    • Light Spectroscopy – Minimal Data