Adhesions are bands of scar tissue that form between internal organs or between organs and the abdominal wall. They range from thin, translucent films that look almost like cobwebs to thick, rope-like bridges of white or pinkish tissue with their own blood supply. Because they form inside the body, most people never see their own adhesions directly, but understanding what they look like helps make sense of how they’re detected, graded, and treated.
How Adhesions Appear During Surgery
The only way to see adhesions directly is during surgery, typically laparoscopy, when a camera is inserted into the abdomen. At their mildest, adhesions appear as thin, nearly see-through sheets of tissue connecting two surfaces that should be separate. These filmy adhesions are sometimes compared to plastic wrap or wet tissue paper stretched between organs. They’re usually pale, whitish, or slightly translucent and can be separated with gentle pressure.
At the other end of the spectrum, adhesions can look like thick, dense cords or broad mats of fibrous tissue. These are opaque, white to yellowish, and sometimes contain visible blood vessels running through them. Mature, well-established adhesions closely resemble tendons or ligament tissue. They can bind the intestines into fixed clumps, tether the uterus to the pelvic wall, or fuse loops of bowel to each other so tightly that separating them risks damaging the organs themselves.
The Spectrum From Filmy to Dense
Surgeons use a grading system (the Zühlke classification) to describe adhesion severity based on their physical characteristics:
- Grade 1 (filmy): Thin, transparent tissue that can be separated with gentle blunt pressure. These look like fine cobwebs or membranes.
- Grade 2 (mild): Slightly thicker bands that still lack significant blood vessels but require more forceful separation.
- Grade 3 (moderate): Dense, clearly visible fibrous tissue that can only be cut apart with a blade or scissors. These often appear white and cord-like.
- Grade 4 (severe): Thick, vascularized tissue so firmly attached that it cannot be separated without damaging the organs involved. These bands contain blood vessels and sometimes nerve fibers.
The transition between grades isn’t always clear-cut. A single patient can have filmy adhesions in one area and dense, vascularized bands in another, depending on the severity of the original injury at each site.
What Adhesions Are Made Of
Understanding their composition explains why they look the way they do. Adhesions begin as a sticky coating of fibrin, the same protein your body uses to form blood clots. After surgery or infection, damaged tissue releases fibrin as part of the healing process. Normally, the body breaks down this fibrin within five to seven days. When it doesn’t get fully reabsorbed, the fibrin acts as a scaffold where scar-forming cells (fibroblasts) move in and start depositing collagen.
By about a week after the initial injury, the adhesion has transformed from a soft, gel-like fibrin deposit into a more structured band of collagen fibers, smooth muscle cells, and a lining of the same tissue that coats abdominal organs. Over time, new blood vessels grow into thicker adhesions, giving them a pinkish or reddish tinge compared to the pale white of simple collagen bands. Some adhesions even develop nerve endings, which is why they can cause pain.
Why You Can’t See Them on Standard Imaging
One of the frustrating realities of adhesions is that they’re largely invisible on standard X-rays and CT scans. The tissue blends in with surrounding soft tissue, making it nearly impossible to distinguish on a still image. This is a major reason adhesions are often diagnosed only when symptoms become severe or during surgery for another reason.
Two imaging techniques can detect adhesions indirectly by looking for their effects on organ movement. Ultrasound uses something called the “visceral slide sign,” where a technician watches whether organs glide freely beneath the abdominal wall as you breathe. Healthy organs slide smoothly. When adhesions are present, the affected area stays fixed or moves sluggishly. This technique helps surgeons identify adhesion-free areas before operating, reducing the risk of accidentally cutting into stuck-together tissue.
A specialized form of MRI called cine-MRI takes a similar approach using video-like sequences. Organs are classified by how much they move: sliding freely (1 cm or more of movement), fine independent motion (less than 1 cm but still moving on their own), synchronous motion (moving only because an adjacent stuck organ pulls them along), or no motion at all. When two organs move in lockstep or don’t move at all, adhesions are the likely cause. This method has about 72% sensitivity and 87% specificity for detecting pelvic adhesions.
How Location Affects Appearance
Adhesions look somewhat different depending on where they form. Bowel adhesions commonly appear as bands or sheets connecting loops of intestine to each other or to the abdominal wall. Because the intestines are constantly moving with digestion, these adhesions tend to form as distinct cords that stretch between two anchor points, sometimes creating a “bridge” that other bowel loops can slide under and become trapped, leading to obstruction.
Pelvic adhesions, which often develop after gynecological surgery, endometriosis, or pelvic infections, tend to form as broader sheets of tissue. The relatively confined space of the pelvis means adhesions can blanket entire organ surfaces, making the uterus, ovaries, and fallopian tubes appear fused together into a single mass. On imaging, these organs move synchronously rather than independently, a hallmark sign of pelvic adhesion disease.
How Common They Are
Adhesions form in a significant number of people who undergo abdominal surgery. In one study, postoperative adhesions were detected in about 36% of patients. Open surgery carries a notably higher adhesion rate than laparoscopic procedures, largely because open surgery involves more tissue handling, larger incisions, and greater exposure of internal surfaces to air. The smaller incisions and gentler tissue manipulation of laparoscopic surgery reduce, but don’t eliminate, the risk.
Not all adhesions cause problems. Many people have adhesions and never know it because the bands are thin enough or located in areas where they don’t interfere with organ function. Adhesions become a clinical concern when they cause chronic pain, pull organs out of position, block the intestines, or contribute to infertility by distorting the anatomy of the fallopian tubes and ovaries.