Adhesions are fibrous bands of internal scar tissue that form between organs or tissues that are normally separate, causing them to stick together. They are the body’s natural response to trauma, serving as an internal repair mechanism following tissue injury or inflammation. These bands can range in appearance from thin, veil-like sheets to thick, dense, and even vascularized structures.
Defining Adhesions: Formation and Types
The vast majority of adhesions develop after abdominal or pelvic surgery, with nearly all patients who undergo open abdominal procedures developing some degree of them. They form when the protective lining of the abdomen, the peritoneum, is damaged by surgical incisions, handling of organs, or internal bleeding. This damage triggers an inflammatory response, leading to the deposition of fibrin, a protein that acts like biological glue.
If the body’s natural process for dissolving this fibrin is overwhelmed, the initial fibrinous bands are then infiltrated by fibroblasts and collagen, which mature into permanent, fibrous adhesions. Adhesions are often classified by their location, such as abdominal (involving the intestines), or pelvic (involving reproductive organs like the fallopian tubes or ovaries). They are also categorized by their composition, ranging from early, transient fibrinous types to more permanent, scarred adhesions made primarily of collagen.
Ultrasound’s Limited View: Addressing the Core Question
Directly visualizing fine, fibrous adhesions with standard ultrasound technology is generally very difficult or impossible. This is because adhesions are made of thin, dense tissue that lacks distinct acoustic properties, preventing them from creating enough contrast against surrounding soft tissues. The presence of intestinal gas can also significantly obscure the view of deeper abdominal structures, further limiting the effectiveness of ultrasound for direct detection.
While the adhesions themselves may be invisible, ultrasound is valuable for detecting the indirect signs of complications they cause. The most common and serious complication is small bowel obstruction (SBO), where an adhesion wraps around or pinches the intestine. An ultrasound technician will look for tell-tale signs of SBO, such as dilated loops of the small bowel that are filled with fluid and the presence of abnormal, reduced, or increased peristalsis. In some cases, ultrasound may show a lack of “visceral slide,” which is the normal gliding movement between adjacent organs, suggesting they are tethered together by adhesive bands.
Advanced Imaging and Definitive Diagnosis
Because non-invasive imaging struggles to directly visualize the fibrous bands, a definitive diagnosis of adhesions often requires a stepwise approach using other methods when complications are suspected. When small bowel obstruction is the concern, Computed Tomography (CT) scans are typically the preferred initial imaging choice. CT scans excel at locating the “transition point,” which is the abrupt change in bowel caliber from a dilated, fluid-filled segment to a collapsed segment, strongly suggesting an external compression like an adhesion is the cause.
For pelvic adhesions, Magnetic Resonance Imaging (MRI) offers superior soft tissue contrast compared to CT, and can sometimes suggest the presence of adhesions, particularly in cases of endometriosis. Even with MRI, very thin adhesions can be missed, making it a highly specific but less sensitive tool for thin adhesive disease. Ultimately, the gold standard for both diagnosing and definitively mapping the extent of adhesive disease is diagnostic laparoscopy, a minimally invasive surgical procedure where a camera is inserted into the abdomen for direct visual inspection.
When Adhesions Require Intervention
Most adhesions do not cause symptoms and do not require any treatment; intervention is reserved for cases where they lead to significant health issues. The most common indications for intervention are recurrent small bowel obstruction, chronic abdominal or pelvic pain that impacts quality of life, and infertility due to pelvic adhesive disease. A complete bowel obstruction is considered a medical emergency that requires immediate attention, often involving surgery.
The surgical procedure to remove or divide adhesions is called adhesiolysis, which can be performed using open surgery or a minimally invasive laparoscopic technique. Laparoscopy is often favored due to lower morbidity and a reduced risk of forming new adhesions. However, the procedure itself carries risks, primarily the potential for new adhesion formation, as surgery can trigger the same healing response. Therefore, the decision to proceed with adhesiolysis involves carefully weighing the potential benefits against the risk of surgical complications and recurrence.