What are omentum adhesions?

What Are Omentum Adhesions?

Omentum adhesions are pathological fibrous tissue bands that abnormally connect the greater omentum to other intra-abdominal structures such as the bowel, abdominal wall, or other organs—structures that should normally remain separate. 1, 2

Definition and Pathophysiology

• Adhesions are fibrous tissue bands that connect surfaces or organs within the peritoneal cavity that are normally separated. 1, 2

• These bands may range from thin films of connective tissue to thick fibrous bridges containing blood vessels and nerve tissue, or direct organ-to-organ adhesions. 3

• The omentum specifically develops adhesions in 70.5% of patients undergoing abdominal surgery, making omental involvement extremely common in adhesive disease. 4

• Adhesions form after peritoneal injury from surgery, trauma, inflammation, or bleeding—with the combination of serosal drying plus bleeding being particularly adhesiogenic. 5

Clinical Significance and Complications

Omental adhesions transform the greater omentum from a protective immune defense organ into a source of clinical problems. 4

• Adhesions account for 55-75% of all small bowel obstructions, representing the most common cause of this life-threatening complication. 1

• Omental adhesions can cause:

  • Small bowel obstruction through direct compression or entrapment 1, 2
  • Chronic abdominal and pelvic pain 2
  • Complications during subsequent surgeries, with bowel injury rates of 6.3-26.9% during adhesiolysis 6

• The omentum plays a protective role by capturing blood clots and preventing visceral adhesions—fresh blood and preformed clots above a critical size consistently induce omental adhesions. 5

Mechanism of Formation

• Adhesions develop due to locally decreased peritoneal fibrinolytic capacity, particularly in ischemic areas of the peritoneum. 7

• They function as a "vascular graft" mechanism, helping guarantee blood supply to ischemic peritoneal areas. 7

• The omentum contains milky spots with inflammatory/immune cells expressing TGF-β3, TGF-β1, and betaglycan, which mobilize after injury and drive the adhesion formation process. 8

• TGF-β1 expression correlates with fibrous adhesion zones, while TGF-β3 is associated with adipose tissue regeneration in healing areas. 8

Clinical Management Implications

• When omental adhesions cause chronic omentitis or symptomatic adhesive disease, omental resection is indicated. 4

• For patients with omental adhesions without omentitis, omental replacement and fixation in the epigastric region anterior to the stomach should be performed. 4

• CT scan achieves 76% accuracy in determining the etiology of bowel obstruction and identifying omental involvement. 1

Key Clinical Caveat

Complete suppression of adhesion formation is not desirable because adhesions serve a protective vascular function—the goal is controlled adhesion formation through meticulous surgical technique and strategic omental placement in high-risk areas. 7