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median arcuate ligament syndrome MALS

What is MALS?

Median Arcuate Ligament Syndrome is also known as: MALS, Celiac Artery Compression Syndrome (CACS), Dunbar Syndrome and Harjola-Marable Syndrome


Benjamin Lipshultz, M.D. wrote the first composite study in 1917 on the anatomical variations of the celiac artery seen during dissections. Contributing to the findings was Dr. PT Harjola who first described MALS in 1963 as a combination of both clinical and radiologic images in a patient with mesenteric ischemia from extrinsic compression of the celiac artery. In 1965, Dr. J. David Dunbar reported successful surgical repair, division of the MAL resulting in decompression of the celiac artery in 15 patients which validated the clinical syndrome.   

What is MALS?

The Median Arcuate Ligament (MAL) is the center fibrous muscular band of the diaphragm that attaches the right and left crura; it is positioned at Thoracic T12/Lumbar L1-2 of the spine. MALS is caused when the ligament descends lower or the celiac artery is anatomically positioned higher on the Aorta causing the ligament to cross over and compress the celiac artery and surrounding tissue which can include the celiac plexus nerves. As of right now there are multiple theories of why MALS occurs within the body. Some of those theories are that this structural anomaly could be congenital, meaning from birth or develop after spinal surgery, abdominal surgery or due to abdominal trauma. While some degree of compression can be seen in the general population without symptoms, these people should be followed closely as people can become symptomatic at any age. Compromised blood flow and inflammation results in changes in oxygen levels (hypoxia/HIF factor and oxidative stress) and nutrients to the abdominal organs and nerves which can result in consequential damage. Nerve irritation and or damage can cause disturbances with myenteric electrical activity to the stomach resulting in the symptoms.


MALS symptoms manifest as numerous gastrointestinal complaints and can range from intermittent mild to chronic debilitating that are triggered after eating or exercise. It is still commonly considered a diagnosis of exclusion, so patients are usually sent for many tests most of which turn out “normal.” Unfortunately, MALS symptoms can all too often be dismissed by clinicians as non-specific, psychosomatic, or psychiatric, leaving many patients to suffer for months and years longer than they need to. Clinical presentation varies and is case specific to each person's symptoms.   

 Common Symptoms associated after eating, exercise, positional movement:

  • Epigastric Pain or Pressure

  • Postprandial Pain or Pressure

  • Chest Pain or Pressure

  • Nausea

  • Diarrhea

  • Constipation

  • Lightheaded

  • Dizziness

  • Bloating

  • Vomiting

  • Weight loss

  • Radiating right or left flank and or back pain

  • Blood Pressure and Pulse issues

  • Near Fainting with Position Changes

  • Orthostasis

Clinical Presentation & Diagnostic Workup

A History & Physical (H&P) are important tools helpful in the diagnosis process. Physical examination may activate tenderness in the epigastric region when palpated. The Doctor may hear a whooshing sound known as an abdominal bruit or thrill in the same epigastric area along with listening for bowel sounds. Observations may include weight loss and malnutrition may be evident. Once MALS is suspected, a diagnostic workup is initiated to include various tests indicative of a diagnosis of MALS and rule out cardiovascular and gastrointestinal issues.  

  • Duplex or Doppler Mesenteric Ultrasound with breathing protocol

  • Computed Tomography Angiography (CTA) with breathing protocol

  • Catheter Abdominal Angiography with contrast dye   

  • Magnetic Resonance Angiography (MRA)

  • CT scan with or without contrast dye chest, abdomen and pelvis

  • Gastric Emptying Transit Motility Study with Small Bowel Follow Through

  • HIDA scan of gallbladder

  • Endoscopy (EGD) and Colonoscopy with Biopsies

Management & Surgical Treatment

The standard treatment is surgical release of the celiac artery by division of the median arcuate ligament (MAL) including overlying lymphatics and soft tissue with or without neurolysis of the compressed nerves and removal of scar tissue. Ultrasound may be used to show restoration of normal blood flow which verifies adequate release of the artery at the time of surgery. Vascular reconstruction of the celiac artery may be decided at the time of surgery or be needed at a later time. In some cases, an omentum fat wrap may be used during surgery to assist with keeping the artery in the correct anatomical position and reduce scar tissue development. For patients with recurrent or persistent abdominal pain re-evaluation for possible narrowing of the celiac artery either due to the formation of scar tissue within the artery wall (intravascular web) or the integrity of the vessel wall has been compromised due to the mechanical compression. Additional procedure/s may include balloon angioplasty, brachial or femoral artery catheter stent placement, patch angioplasty graft or Superaceliac Aorta-to-Celiac Bypass with Dacron graft or saphenous vein. Splanchnic nerve or Celiac Plexus Block is advised if pain continues and vascular studies show open vessels. Percutaneous Transluminal Angioplasty (PTA) or endovascular stent placement is not recommended before surgical division of the MAL due to failure from the external compression crushing the stent which can add increased risk for artery wall damage and or dissection.  

Currently, there are three types of surgery offered for MALS:

  • Open surgery - Laparotomy Thoracoabdominal or Transthoracic approach

  • Laparoscopic surgery - Laparoscopic Three Dimensional High Definition Trans - peritoneal Retrograde or Antegrade or Retroperitoneal endoscopic lysis  

  • Robotic/Hybrid surgery      

Additional Intervention offered after surgical release:

  • Balloon Angioplasty

  • Stent Placement    

Recommended Follow Up Care

Short and Long term follow up is recommended with vascular studies to reinforce continuity of care in the event of recurrence.

Consequential Cascade of the Disease Process

Important for people to receive prompt accurate testing and initiate treatment plan to resolve or help reduce short or long term effects afflicted or inflicted by MALS.

  • Chronic Mesenteric Ischemia can result in breakdown of the epithelial barrier tight junctions

  • Dissection of the Celiac Artery

  • Pancreaticoduodenal and Splenic Artery Aneurysms

  • Exocrine Pancreatic Insufficiency (EPI)

  • Gallbladder and Biliary (Sphincter of Oddi/SOD) Dyskinesia 

  • Gastroparesis

  • Splenomegaly (enlarged spleen)

  • Lymphadenopathy

  • Liver Ascites/benign tumors

  • Enlarged Liver/Fatty Liver

  • Small Intestinal Bacterial Overgrowth (SIBO)

  • Reflux acid, nonacid, bile

  • Postural Orthostatic Tachycardia

  • Hypersensitized pain transmission

  • Acute, Chronic, or Minimal Change Pancreatitis

Looking for more information on MALS?

Follow the link below to our resources page.

What is MALS
Clinical Presentation & Diagnostic Workup
  • 24 hr pH Impedance Probe

  • Esophageal Manometry

  • Gastric Tonometry

  • Blood work panels

  • Chest x-ray

  • Electrocardiogram (EKG)

  • Splanchnic Nerve (SNB) or Celiac Plexus Block (CPB)

  • Autonomic Testing

Management & Surgical Treatment
Recommended Follow Up Care
Consequential Cascade of the Disease Process
Additional MALS Resource Information
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