May-Thurner Syndrome

Also Known As:

MTS, Iliac Vein Compression Syndrome, IVCS, Cockett's Syndrome, Iliocaval Compression Syndrome

What is May-Thurner Syndrome?

May-Thurner Syndrome occurs when the left common iliac vein is compressed against the lumbar spine by the right common iliac artery.

The common iliac arteries are the main blood vessels supplying the legs with oxygenated blood, and the common iliac veins are the main blood vessels carrying deoxygenated blood back out of the legs. As a result of the body’s anatomy, the right common iliac artery crosses the left common iliac vein. This arrangement of the blood vessels isn’t problematic under normal circumstances, except when some abnormality causes increased compression at this junction.

This compression causes the blood flow out of the left leg to be restricted (circulatory stasis) which can lead to Deep Vein Thrombosis. The compromised blood flow can also cause collateral blood vessels to form, resulting in neurological symptoms like tingling and numbness.


Factors that can increase the risk of developing May-Thurner Syndrome include:
•   Injury or trauma to the lower back
•   Surgery in the lower back
•   Old age
•   Being overweight or obese
•   Congenital condition, causing abnormal arrangement of the iliac blood vessels
•   Scoliosis
•   Pregnancy
•   Have had more than one child
•   Dehydration
•   Birth control pills or hormone replacement therapy
•   Blood-clotting disorders
•   Prolonged bed rest, such as during a long hospital stay, or paralysis


May-Thurner Syndrome has very few symptoms. Many people do not realise they have the condition until the symptoms for Deep Vein Thrombosis appear, or they’ve gone through emergency treatment for a Pulmonary Embolism.

The symptoms May-Thurner Syndrome may include:
•   Pain and swelling in the lower body
•   Tingling and numbness in the lower body

If a person notices any symptoms of May-Thurner Syndrome, it is crucial to seek immediate medical attention, because severe life-threatening complications can occur.

Diagnosis & Treatment

The lack of symptoms of May-Thurner Syndrome makes it hard for doctors to diagnose. The doctor may begin with a physical examination, blood tests and scans in order to determine complications or other underlying conditions. The doctor may also order the following tests:
•   Ultrasound
•   CT scan
•   MRI scan
•   Venogram

Treatment for May-Thurner Syndrome may include:
•   Balloon Angioplasty: To insert a stent in the vein to keep it open so blood can flow freely.
•   Bypass surgery: Blood is rerouted around the compressed part of the vein with a bypass graft.
•   Repositioning the right iliac artery: Move the right iliac artery behind the left iliac vein so it doesn’t put pressure on it.

Other treatments will be used to resolve the symptoms caused by underlying conditions, or by any associated complications that may have developed.

Additional Information

There are case reports of the inferior vena cava being compressed by the iliac arteries or right-sided compression syndromes, but the vast majority are on the left side.

Current estimates are that May-Thurner Syndrome is three times more common in women than in men.

Also see: Thrombosis, Deep Vein Thrombosis

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Published Date:

18th December 2018


Mediv8 Admin