Omental adhesions are bands of scar tissue that form when the omentum, a large sheet of fatty tissue hanging inside your abdomen, sticks to nearby organs, the abdominal wall, or surgical sites. The omentum normally drapes freely from the lower edge of your stomach down to your colon, acting as a kind of internal apron. When injury, surgery, or inflammation disrupts this area, the healing process can cause the omentum to fuse to surfaces it shouldn’t be attached to. These adhesions are extremely common: they develop after up to 93% of general abdominal surgeries and up to 97% of open gynecologic procedures.
What the Omentum Does Normally
The greater omentum is a two-layered hammock of fibrous, fatty tissue that stretches from the greater curvature of the stomach to the transverse colon. It has long been called the “policeman of the abdomen” because it migrates toward sites of injury or infection, physically wrapping around inflamed tissue to contain the problem. If your appendix perforates, for example, the omentum often plugs the hole before a surgeon even gets there.
This protective behavior involves fibrin, a protein the body uses to form clots and seal wounds. During normal healing, fibrin is deposited and then broken down in a balanced cycle. When that balance is disrupted by surgery, infection, or chronic inflammation, fibrin deposits persist and harden into permanent adhesive bands. That is how the omentum’s natural healing response becomes the source of adhesions.
What Causes Omental Adhesions
Prior abdominal surgery is the most common cause by a wide margin. Nearly 90% of abdominal adhesions form after surgery, with open procedures (laparotomy) carrying a far higher risk than laparoscopic ones. In one study, 95% of patients who had previously undergone open abdominal surgery were found to have adhesions when surgeons looked during a later operation. The type of initial surgery varied widely, from cancer removal and bowel operations to appendectomies, gallbladder removal, and hysterectomies.
Surgery isn’t the only trigger. Several inflammatory and infectious conditions cause adhesions without any prior operation:
- Endometriosis and pelvic inflammatory disease are the most common non-surgical causes in women.
- Crohn’s disease and diverticular disease can produce adhesions through chronic bowel inflammation.
- Peritonitis, an infection of the abdominal lining, disrupts the normal fibrin cycle and promotes tissue fusion.
- Radiation therapy to the abdomen or pelvis can cause adhesions as a delayed side effect, with severity depending on the radiation dose and the area treated.
- Long-term peritoneal dialysis for kidney failure is another recognized cause.
In some cases, people are born with abdominal adhesions that were never triggered by surgery or illness.
Symptoms and When They Cause Problems
Most omental adhesions cause no symptoms at all. Many people live their entire lives unaware they have them. When adhesions do cause trouble, the symptoms typically fall into two categories: chronic pain and bowel obstruction.
Chronic pain develops when adhesions restrict the normal movement of your organs. Your intestines, stomach, and other structures need to shift and slide as you move, breathe, and digest food. Adhesions can tether them in place, creating a persistent pulling or aching sensation in the abdomen or pelvis. This visceral pain can be difficult to pinpoint and often worsens with certain movements or after eating.
Bowel obstruction is the more serious concern. Adhesive bands can kink or squeeze loops of the small intestine, similar to the way a garden hose gets kinked. About 60% of small bowel obstructions are caused by adhesions, mostly in people with a history of open abdominal surgery. Obstruction from omental bands specifically is rare compared to other adhesion types, but it does occur. The symptoms of obstruction are hard to miss: severe abdominal pain, cramping, bloating, nausea, vomiting, and the inability to pass gas or stool. This can happen weeks after surgery or decades later, and it requires emergency medical attention because an untreated obstruction can lead to tissue death and life-threatening infection.
A Rarer Complication: Omental Torsion
Adhesions can also set the stage for omental torsion, a condition where the omentum twists around a fixed point. The twist compresses veins first, causing the tissue to swell and become congested with blood. If it progresses, arterial blood flow is cut off, leading to tissue death. Half of patients with omental torsion develop a low-grade fever, and about half have a palpable abdominal mass along with localized tenderness.
The pain typically starts suddenly in the lower right abdomen, which makes it easy to confuse with appendicitis. Nausea, vomiting, and worsening pain over hours are common. CT scans can show a characteristic “whirl sign,” a fatty mass with twisted blood vessels spiraling around a central point. Treatment usually requires surgery to remove the affected tissue.
How Omental Adhesions Are Diagnosed
Diagnosing adhesions is notoriously difficult because the adhesions themselves are not usually visible on standard imaging. Ultrasound has historically been unreliable for detecting them, since intestinal gas and abdominal fat interfere with the signal. MRI performs better for detecting adhesions between organs and the abdominal wall, with a reported sensitivity of about 88% and specificity of 93%. CT scans are most useful when adhesions have already caused a bowel obstruction, since the blocked, dilated intestine shows up clearly even if the adhesive band itself does not.
In practice, many adhesions are discovered incidentally during surgery for another reason, or they are suspected based on symptoms in someone with a known history of abdominal surgery. Direct visualization during laparoscopy remains the most definitive way to confirm their presence.
Treatment Options
Asymptomatic adhesions don’t require treatment. If you learn you have them incidentally, there’s typically nothing that needs to be done unless symptoms develop.
When adhesions cause chronic pain or bowel obstruction, surgical division of the scar bands (called adhesiolysis) is the standard treatment. This can be done through minimally invasive laparoscopic or robotic surgery, or through traditional open surgery. Laparoscopic approaches generally result in less pain afterward, shorter hospital stays, and a lower risk of forming new adhesions. However, the conversion rate from laparoscopic to open surgery is significant, running between 32% and 38% in published studies, because dense or widespread adhesions can make the minimally invasive approach too risky.
Open surgery remains necessary when adhesions are very dense or matted together, when the bowel is significantly swollen, or when there are signs of tissue death or perforation. The tradeoff is more postoperative pain, a longer recovery, and a higher chance of new adhesions forming in the future. The decision between approaches depends on the extent and location of the adhesions, your surgical history, and your surgeon’s experience.
Preventing Adhesions During Surgery
Because adhesions are so common after abdominal surgery, several barrier products have been developed to reduce their formation. These are placed between tissues during surgery to physically keep healing surfaces from sticking together while the body completes its repair process.
A bioresorbable film made from hyaluronic acid and carboxymethylcellulose (sold as Seprafilm) has been shown to reduce the risk of small bowel obstruction and the severity of adhesions that do form. In one study, 33% of patients treated with a similar membrane had no adhesions at all, compared to just 10% in the untreated group. Liquid barriers, such as a 4% icodextrin solution bathed over surgical sites, have also shown promise, reducing the recurrence rate of adhesion-related bowel obstruction from about 11% to roughly 2% in one trial.
No barrier eliminates adhesion risk entirely. Minimally invasive surgical techniques themselves are one of the most effective prevention strategies, since smaller incisions mean less tissue disruption and a lower likelihood of scar tissue forming in the first place.