Internal scar tissue is fibrous tissue that forms inside your body as part of the healing process after surgery, injury, infection, or chronic inflammation. It works the same way as a scar on your skin: your body patches damaged tissue with tough, fibrous material. But because it forms between organs, around intestines, or inside joints and lungs, internal scar tissue can quietly cause problems ranging from chronic pain to infertility to bowel obstruction. The medical term you’ll often hear is “adhesions” when this scar tissue forms bands that connect organs to each other or to the walls of your abdominal cavity.
How Internal Scar Tissue Forms
Your body heals wounds in three overlapping phases. First comes inflammation, where blood clotting and immune cells rush to the injury site. Starting around day three, specialized repair cells called fibroblasts migrate to the damaged area and begin producing collagen, the protein that gives scar tissue its structure. This proliferative phase lasts roughly three weeks.
The final phase, remodeling, begins around week three and can continue for a year or longer. During this stage, your body reorganizes the collagen fibers and breaks down temporary repair proteins. In normal healing, the scar matures into a thin, relatively flexible patch. But when fibroblasts overproduce collagen or fail to shut down on schedule, the result is dense, excessive scar tissue. Some of these fibroblasts transform into a more aggressive cell type that actively contracts and stiffens the tissue, which is why internal scars can tighten around organs and pull structures out of their normal position.
Where It Develops and Why
Surgery is the most common trigger. Adhesions form after 67% to 93% of general abdominal surgeries, and rates climb as high as 97% after open gynecologic procedures. Any time a surgeon cuts, cauterizes, or handles internal tissue, the body’s healing response kicks in and can overshoot. Laparoscopic (minimally invasive) surgery produces fewer adhesions than open surgery, but doesn’t eliminate the risk.
Surgery isn’t the only cause. Internal scar tissue also develops from:
- Infections such as pelvic inflammatory disease or peritonitis, which inflame tissue and trigger the same fibroblast response
- Endometriosis, where tissue similar to the uterine lining grows outside the uterus and causes repeated cycles of inflammation and scarring
- Radiation therapy, which damages tissue and provokes fibrosis in the treatment area
- Chronic inflammation from conditions like Crohn’s disease, which can lead to scarring that narrows sections of the intestine
Internal scar tissue can form in the lungs (pulmonary fibrosis), around joints, within the uterus, throughout the abdominal cavity, or essentially anywhere tissue has been damaged and repaired.
Symptoms Depend on Location
Many people with internal scar tissue have no symptoms at all. The adhesions exist silently and never cause trouble. When symptoms do appear, chronic abdominal or pelvic pain is the most common complaint, caused by scar bands restricting the normal movement of organs.
In the abdomen, adhesions can kink or compress the intestines, creating a partial or complete bowel obstruction. When food, liquid, and gas can’t pass through, you may experience severe abdominal pain, cramping, bloating, nausea, vomiting, and an inability to pass gas or have a bowel movement. A complete obstruction that cuts off blood supply to a section of intestine is a surgical emergency.
In the pelvis or uterus, scar tissue can compress or block parts of the reproductive system. This is a recognized cause of infertility in women, particularly after gynecologic surgery or pelvic infections. Scar tissue inside the uterine cavity can also lead to abnormal or absent periods.
Why It’s Hard to Diagnose
One of the most frustrating things about internal scar tissue is that standard imaging often can’t see it. Thin adhesion bands don’t show up reliably on CT scans or X-rays. Ultrasound can help evaluate scarring around nerves, including the degree of nerve injury and the amount of scar tissue present. MRI can sometimes identify indirect signs like swelling or visualize nerves that are tethered by scar tissue, but it’s not a definitive tool for mapping adhesions throughout the abdomen.
In many cases, the only way to confirm adhesions is during surgery itself, when a surgeon can directly see and feel the scar bands. This means doctors often diagnose internal scar tissue based on a combination of your surgical history, symptom pattern, and the process of ruling out other conditions.
Treatment Options
Physical therapy is a first-line approach for managing symptoms from internal scar tissue. Techniques like scar mobilization, myofascial release, lymphatic drainage, and instrument-assisted soft tissue work aim to improve how the scar tissue fibers align and reduce the restriction on surrounding structures. These manual therapies won’t dissolve scar tissue, but they can improve mobility, reduce pain, and help prevent further tightening.
When conservative treatment isn’t enough, surgery to cut away scar tissue (called adhesiolysis) is an option. The catch is significant: surgery itself creates new opportunities for scar tissue to form. Recurrence rates after adhesiolysis range from 20% to 63%, depending on the severity of the original adhesions and the surgical approach used. For intrauterine adhesions specifically, studies have found recurrence rates from 3% to 24% for mild cases, climbing sharply for more severe ones.
Preventing Scar Tissue During Surgery
Surgeons now have barrier products designed to reduce adhesion formation. Bioresorbable membranes placed between tissues at the end of surgery create a temporary physical shield that keeps healing surfaces from sticking together. These barriers dissolve on their own over days to weeks.
Clinical data on one widely used membrane showed that 33% of treated patients developed no adhesions at all, compared to only 10% in control groups. A meta-analysis of 13 trials involving over 3,600 patients found the membrane significantly reduced the risk of small bowel obstruction and the overall severity of adhesions. Another study found it cut chronic abdominal complaints from 78% down to 35%.
These barriers aren’t perfect. Some studies have linked them to a higher rate of certain surgical complications, including leaks at intestinal reconnection sites. Your surgeon weighs this tradeoff based on your specific procedure and risk level. Minimally invasive surgical techniques, careful tissue handling, and keeping tissues moist during surgery also help reduce adhesion formation, though none of these strategies eliminates the risk entirely.