What is ileal resection and anastomosis?

What is Ileal Resection and Anastomosis?

Ileal resection and anastomosis is a surgical procedure where a diseased segment of the ileum (the final portion of the small intestine) is removed and the remaining healthy ends of bowel are reconnected to restore intestinal continuity.

Anatomical Context

The ileum is the terminal portion of the small intestine, extending from the jejunum to the ileocecal valve where it connects to the colon 1. When disease affects this segment, surgical removal becomes necessary, followed by reconnection of the bowel ends.

The Two Components of the Procedure

Resection (Removal)

• The surgeon removes the diseased segment of ileum along with its associated mesentery (the tissue containing blood vessels and lymphatics) 1
• Margins of disease-free bowel are identified and the bowel is transected at these points 1
• The length of remaining small bowel is carefully measured, as this has critical implications for absorption and risk of short bowel syndrome 1

Anastomosis (Reconnection)

• The two healthy ends of bowel are surgically joined together to restore intestinal continuity 1
• Multiple anastomotic techniques exist, including:
  • End-to-end: Direct connection of the two cut ends 2
  • Side-to-side: The sides of two bowel segments are connected, creating a wider opening 1
  • End-to-side: One end is connected to the side of another segment 1

Common Clinical Scenarios

Crohn's Disease

For ileocolic Crohn's disease, wide lumen stapled ileocolic side-to-side (functional end-to-end) anastomosis is the preferred technique 1. This approach:

• Creates a larger anastomotic opening that reduces stricture risk
• Is associated with lower recurrence rates compared to other techniques
• Can be performed laparoscopically in appropriate cases 1

Ulcerative Colitis

When the terminal ileum is preserved after colectomy, it may be anastomosed to the rectum (ileorectal anastomosis) or fashioned into a pouch and connected to the anus (ileal pouch-anal anastomosis) 3, 4, 5.

Cancer

For colon cancer involving the terminal ileum, resection includes at least 5 cm margins on either side of the tumor with removal of the lymphatic drainage 1.

Critical Postoperative Considerations

Short Bowel Syndrome Risk

• Risk increases dramatically when remaining small bowel approaches 100 cm with an ileostomy or 50 cm with colon intact 1
• The length of healthy remaining small bowel must be documented during surgery 1

Bile Acid Malabsorption

• Occurs in more than 80% of patients following ileal resection 6
• Resections as short as 5 cm of terminal ileum can cause bile acid malabsorption 6
• Results in diarrhea, steatorrhea, and altered stool characteristics 6

Small Intestinal Bacterial Overgrowth (SIBO)

• Occurs in approximately 30% of patients after bowel resection, particularly when the ileocecal valve is removed 6
• Loss of the ileocecal valve allows retrograde bacterial migration from colon to small intestine 6

Surgical Approach Options

Laparoscopic approach is preferred for ileocolic resections where appropriate expertise is available 1. Benefits include:

• Reduced postoperative pain
• Shorter hospital stay
• Reduced duration of ileus 1
• Similar long-term oncological outcomes to open surgery 1

However, in complex cases or recurrent resections, there is insufficient evidence to recommend laparoscopy as first choice 1.

Common Pitfalls to Avoid

• Tension on the anastomosis: Both bowel segments must be adequately mobilized to ensure tension-free connection 2
• Inadequate blood supply: Vascular structures must be preserved to ensure viability of the anastomotic ends 2
• Failure to measure remaining bowel length: This measurement is critical for predicting malabsorption risk 1
• Ignoring postoperative symptoms: New diarrhea, steatorrhea, or malnutrition warrant investigation for bile acid malabsorption or SIBO 6