Median Arcuate Ligament Syndrome (MALS)

Overview

What is median arcuate ligament syndrome?

Median arcuate ligament syndrome (MALS) is a condition in which the median arcuate ligament presses too tightly on the celiac artery (a major branch of the aorta that delivers blood to the stomach, liver, and other organs) and the nerves in the area (celiac plexus).

median arcuate ligament | Cleveland Clinic

Ligaments are bands of tissue that connect one bone or cartilage to another. The median arcuate ligament is shaped like an arch and goes around the aorta (the artery in the heart that carries blood throughout the body) to connect the diaphragm to the spine.

In a patient with MALS, the median arcuate ligament essentially acts like a hammer and the celiac axis acts like an anvil, compressing (squeezing) the nerves in between. This causes a number of symptoms, such as pain in the abdomen that can be made worse by eating or activity.

It is important to differentiate median arcuate ligament syndrome (MALS) from median arcuate ligament compression. Median arcuate ligament compression occurs in about 10-25% of the population and does not cause any symptoms. In a very small number of these individuals, MALS is present, and patients will have the symptoms listed below.

MALS occurs most often in thin, younger women. It is a very rare condition.

Symptoms and Causes

What are the signs and symptoms of median arcuate ligament syndrome?

The first sign of MALS is pain in the upper abdomen after eating. The pain causes patients to avoid eating, which can lead to weight loss (often more than 20 pounds).Other associated symptoms may include:

  • Nausea
  • Diarrhea
  • Vomiting
  • Delayed gastric emptying (a delay in food moving from the stomach into the small intestine)

What causes median arcuate ligament syndrome?

It is believed that MALS is caused by the median arcuate ligament compressing, or pinching the celiac plexus nerves over the celiac artery. The squeezing of these nerves can cause a pain similar to the pain patients with carpal tunnel syndrome feel in their hands. Another cause may be the lack of blood flow to the organs supplied by the celiac artery, though this theory is controversial.

Diagnosis and Tests

How is median arcuate ligament syndrome diagnosed?

If your doctor thinks you may have MALS, he or she will review your medical history and perform a physical examination. The doctor may also order certain tests, including blood work and imaging tests, to help rule out more common causes of your symptoms, such as gastroesophageal reflux disease (GERD), gastritis, gastroparesis, or problems with your pancreas, liver, gallbladder, spleen, or intestines.

Once these conditions are ruled out, your doctor may order a test called a mesenteric duplex ultrasound to check blood flow through the celiac artery and compression of the celiac plexus. Another helpful imaging test would be a CT or MRI angiogram, which can give a better picture of your celiac artery and aorta.

Once the diagnosis of MALS is suspected, our protocol at the Cleveland Clinic includes a three-step process:

  1. Your records will be reviewed and any additional imaging tests will be repeated or ordered (such as a mesenteric ultrasound of the celiac axis or a CT/MRI angiogram).
  2. You will be examined by one of our minimally invasive surgery specialists in the Section of Surgical Endoscopy of the Digestive Disease and Surgery Institute. A vascular surgeon in the Heart and Vascular Surgery Institute will also be available for consultation in more complex cases, if needed.
  3. You will also be evaluated by one of our pain management specialists for a potential celiac plexus block procedure. This offers temporary relief from the symptoms of MALS, and helps to confirm the diagnosis for the patient and the entire medical team.

What is a celiac plexus block?

A celiac plexus block is an injection of medication to help relieve pain in the abdomen.

celiac plexus block | Cleveland Clinic

Median arcuate ligament release

If you have a celiac plexus block, you will be given an intravenous medication to relax you. Then you will lie on your stomach on an x-ray table. The doctor will numb an area of skin on your back with a local anesthetic. Then, guided by an x-ray, the doctor will:

  • Insert a thin needle into your back, next to your spine, and inject an anesthetic.
  • Insert a second needle on the other side of your spine.
  • Inject dye to make sure the medication goes to the correct spot.
  • Inject pain medication, such as epinephrine, clonidine, or a steroid. Alcohol or phenol also may be injected to destroy the nerves.

The procedure usually takes less than 30 minutes, and you can go home the same day. Your abdomen may feel warm, and you may begin to feel less abdominal pain.

Patients usually need a series of injections (between two and 10) to continue the pain relief. For some people, a celiac plexus block can relieve pain for weeks. For others, the relief can last years. Many can return to their normal activities.

Management and Treatment

How is median arcuate ligament syndrome treated?

Once the diagnosis of MALS is confirmed, most patients will be offered a minimally invasive (laparoscopic/robotic) approach to relieving the compression of the median arcuate ligament on the aorta. In this technique, the surgeon makes five to six small (approximately 1/2 inch) incisions (cuts) and inserts instruments to separate the median arcuate ligament and divide the nerves (neurolysis).

Most patients who have laparoscopic surgery for MALS stay overnight in the hospital and begin eating a normal diet the next morning. Patients will have some discomfort and pain from the incisions, and will receive medications to relieve the pain. Most patients say that their MALS symptoms, such as pain with eating, improve after the surgery. Most patients are able to return to normal activities within two to four weeks.

About 10% of patients have a traditional “open” operation, in which a large incision is made down the middle of the abdomen, often with the assistance of one of the vascular surgeons. Patients who have this procedure may need to stay in the hospital for three to five days for recovery, and can usually return to normal activities within four to six weeks.

What is a celiac plexus block?

A celiac plexus block is an injection of medication to help relieve pain in the abdomen.

celiac plexus block | Cleveland Clinic

Median arcuate ligament release

If you have a celiac plexus block, you will be given an intravenous medication to relax you. Then you will lie on your stomach on an x-ray table. The doctor will numb an area of skin on your back with a local anesthetic. Then, guided by an x-ray, the doctor will:

  • Insert a thin needle into your back, next to your spine, and inject an anesthetic.
  • Insert a second needle on the other side of your spine.
  • Inject dye to make sure the medication goes to the correct spot.
  • Inject pain medication, such as epinephrine, clonidine, or a steroid. Alcohol or phenol also may be injected to destroy the nerves.

The procedure usually takes less than 30 minutes, and you can go home the same day. Your abdomen may feel warm, and you may begin to feel less abdominal pain.

Patients usually need a series of injections (between two and 10) to continue the pain relief. For some people, a celiac plexus block can relieve pain for weeks. For others, the relief can last years. Many can return to their normal activities.

Outlook / Prognosis

What type of follow-up care is needed after median arcuate ligament syndrome surgery?

Most patients have a duplex ultrasound one month after surgery to make sure that there is no further compression of the median arcuate ligament. Some patients continue to have narrowing of the celiac artery because of scar tissue that has built up. This usually does not cause symptoms after surgery and can be treated with non-surgical techniques such as medications or, in rare cases, another celiac plexus block. Occasionally, other endovascular therapies may be needed. A small group of patients who have repeated episodes of MALS may be candidates for a second attempt at the release of the scar tissue. These patients, however, are at much higher risk (greater than 50%) of needing an open operation (with the assistance of a vascular surgeon).

Resources

Cleveland Clinic’s MALS Team

At Cleveland Clinic, a multidisciplinary team works together to evaluate and treat patients with MALS.

Specialists from the Digestive Disease & Surgery Institute work with other specialists such as vascular surgeons when necessary to provide optimal care to patients with MALS.

Last reviewed by a Cleveland Clinic medical professional on 09/27/2017.

References

  • El-Hayek KM, Titus J, Bui A, Mastracci T, Kroh M. Laparoscopic median arcuate ligament release: are we improving symptoms? J Am Coll Surg 2013 Feb;216(2):272-9. doi: 10.1016/j.jamcollsurg.2012.10.004. Epub 2012 Nov 21.
  • Weber JM, Boules M, Fong K, Abraham B, Bena J, El-Hayek K, Kroh M, Park WM. Median Arcuate Ligament Syndrome Is Not a Vascular Disease. Ann Vasc Surg 2016 Jan;30:22-7. doi: 10.1016/j.avsg.2015.07.013. Epub 2015 Sep 10.
  • Genetic and Rare Diseases Information Center. Celiac artery compression syndrome Accessed 9/28/2017.
  • Jimenez JC, Harlander-Locke M, Dutson EP. Open and laparoscopic treatment of median arcuate ligament syndrome. J Vasc Surg. 2012 Sep;56(3):869-73.

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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy