Embolization and Transarterial Periarticular Embolization in Interventional Radiology for Tumors and Other Diseases

In embolization, special substances (medically known as embolization agents) are injected into blood vessels, thereby blocking them from the inside. Embolization can stop bleeding and shrink tumors without the need for surgery.

Specifically,

• hardening liquids (including Ethibloc, Histoacryl, and ethylene-vinyl alcohol copolymer),
• small metal coils, or
• plastic particles (Gelfoam, polyvinyl alcohol, gelatin)

as embolization agents. When alcohol-containing liquids are used, the procedure is also referred to as chemoembolization.

The injected embolization material is carried along by the bloodstream and then becomes lodged. This causes these vessels (usually arteries) to be occluded or sealed, thereby stopping the bleeding. Embolization can also be used to cut off blood supply to diseased tissue (e.g., tumors). This causes the tissue to die. 

In addition, embolization can reduce blood loss during the surgical removal of a well-vascularized tumor. To achieve this, the feeding blood vessels must be occluded beforehand.

Embolization can be used for the following conditions:

• Bleeding
• Accident-related tears in a blood vessel wall (vascular ruptures) 
• Congenital or acquired malformations (angiomas)
• Dilations of the vessel wall (aneurysms)
• abnormal connections between two blood vessels (fistulas) or in cases of
• cancerous tumors 

Embolization can be used to treat fistulas and benign uterine tumors (uterine fibroids). In these cases, embolization is a standalone treatment.

For most cancers and vascular malformations, embolization is one component of a comprehensive treatment plan. In these cases, embolization is generally used to

• improve the conditions for surgery or radiation therapy or
• minimize the number of pathologically altered blood vessels.

Similar to normal tissue, cancerous tumors also require nutrients and oxygen. These are supplied via the blood vessels. Since cancer cells divide particularly rapidly, they depend on a very good blood supply. By blocking the supplying vessels through embolization, the tumor is cut off from the blood supply and thus from nutrients.

In this way, the cancer cells are “starved.” This leads to a halt in growth and, in some cases, a significant reduction in the size of the tumor. Symptoms caused by the spread of the tumor are alleviated.

Not every tumor is a candidate for embolization. Embolization can be performed primarily for the following types of cancer:

• benign uterine cancer
• Liver cancer and metastases from other cancers in the liver
• Cancer of the vertebral bodies
• Renal cell carcinoma
• cancer-like vascular growths (hemangiomas)

In addition, embolization has shown promising results for certain forms of benign prostate enlargement (benign prostatic hyperplasia). However, this treatment is still considered experimental and is recommended only as part of clinical trials.

Aneurysms are dilations or bulges in blood vessel walls. They can rupture and cause life-threatening bleeding (e.g., in the brain). Aneurysms of the cerebral arteries (known as cerebral aneurysms) also carry a high surgical risk.

Doctors are increasingly treating aneurysms with metal coils as part of an embolization procedure. Embolization has proven particularly effective for cerebral aneurysms, which are difficult to treat surgically.

Vascular occlusion procedures can also be used for acute bleeding in the nasopharyngeal region resulting from

• severe accidents,
• following surgical procedures, or
• in cases of severe nosebleeds (epistaxis) with no identifiable cause

to temporarily or, if necessary, permanently stop the bleeding.

Embolization is

• using a catheter (thin tube) or
• by direct puncture (targeted insertion of a needle) through the skin (percutaneously)

. In catheter embolization, the femoral artery is punctured with a cannula under local anesthesia. Subsequently, under X-ray guidance, a guidewire is first inserted, followed by a catheter, and both are advanced to the blood vessel that is to be occluded.

The embolization material is then introduced through the catheter to block blood flow either temporarily or permanently. Finally, a follow-up X-ray is taken, and the catheter is removed.

In direct puncture, the vessel to be blocked is punctured directly with a hollow needle. The physician then injects the blocking substances or particles directly through the hollow needle.

A specific form of embolization is known as transarterial chemoembolization (TACE). It is used to treat liver cancer and liver metastases. In this procedure, the blood supply to the tumor is blocked after it has been exposed to local chemotherapy.

In conventional chemotherapy, the anticancer drug (known as a cytostatic agent) is administered orally or through a vein in the arm. It then spreads throughout the entire body.

In chemoembolization, the drug is injected directly into the area of the tumor. Because the tumor is isolated from the rest of the bloodstream, the drug can act on the cancer cells for a longer period of time. It is not flushed away by the circulatory system. As a result, it accumulates in the cancer cells and effectively kills them.

Embolization allows the active ingredient of chemotherapy to be confined to a specific part of the vascular system, such as here in the liver © samunella | AdobeStock

As with all invasive treatments, embolization can also lead to complications or side effects. These are primarily caused by the spread of the injected substances and their effects on other organs. The use of catheters can lead to bleeding or bruising, among other things.

A condition known as post-embolization syndrome is frequently observed. It is characterized by flu-like symptoms such as

• nausea,
• fever,
• limb pain, and
• abdominal pain

and responds well to medication. Localized pain may also occur during the procedure, which can be relieved with appropriate pain medication.

In addition, women who wish to have children are sometimes advised against undergoing embolization for uterine cancer. The long-term effects of this still relatively new treatment approach have not yet been fully clarified. Damage to healthy areas of the uterus therefore cannot be completely ruled out.

Following the treatment, 24 hours of bed rest is required. If further surgery is planned, it is performed shortly after the embolization.

Chemoembolization often needs to be repeated at regular intervals to achieve the intended treatment goal.

In cases of cancer, regular follow-up monitoring using imaging techniques such as 

• magnetic resonance imaging (MRI), 
• computed tomography (CT), or 
• ultrasound 

.

For some types of cancer (including benign uterine cancer), results are visible as early as 1 to 2 weeks after the procedure. Doctors can then determine whether the treated tumor has been destroyed.

The destruction of the cancer cells is indicated by the absence of detectable blood flow (known as devascularization).

What is embolization?

Embolization is a procedure in interventional radiology in which one or more blood vessels are selectively occluded. Special particles, coils, or other embolic materials are delivered into the affected artery via a catheter. This reduces blood flow and treats pathologically altered tissue. This treatment is used, among other things, for bleeding, tumors, aneurysms, or varicose veins.

How is embolization performed?

The embolization procedure is usually performed under local anesthesia. A thin catheter is often inserted through the groin or into the femoral artery and advanced to the desired location under angiographic guidance using contrast dye. Particles, metal coils, or other materials can then be delivered via a microcatheter. Embolization is targeted and spares surrounding tissue.

What is transarterial periarticular embolization?

Transarterial periarticular embolization is a modern procedure for treating chronic joint pain. It involves the targeted occlusion of small, pathologically altered blood vessels surrounding a joint. Particularly in cases of gonarthrosis and osteoarthritis of the knee, the targeted reduction of blood flow to inflamed areas can help relieve pain. The procedure is offered at specialized centers for interventional radiology.

For which conditions is embolization used?

Embolization is used to treat tumors, bleeding, aneurysms, varicose veins, and chronic pain. In oncology, for example, procedures such as chemoembolization are used to treat tumors. In addition, occluding blood vessels can help stop bleeding or specifically reduce the blood supply to a tumor. Chronic joint pain can also be alleviated by this treatment.

What are the benefits of embolization?

Embolization is a minimally invasive alternative to many surgical procedures. The procedure typically requires only small incisions and often allows for a quick recovery. Compared to open surgery, the burden on patients can be lower. In addition, the therapy can be applied in a highly targeted manner to relieve symptoms and improve joint function.