What is Median Arcuate Ligament Syndrome (MALS)?

From the Guidelines

MALS (Median Arcuate Ligament Syndrome) is a rare vascular compression disorder where the median arcuate ligament, a fibrous arch connecting the diaphragm sides, presses on the celiac artery, restricting blood flow to abdominal organs, and the definitive treatment is surgical release of the ligament (laparoscopic or open median arcuate ligament release) which has been associated with symptomatic relief in 84.6% of patients 1.

Key Characteristics of MALS

• Patients typically experience chronic abdominal pain, especially after eating, weight loss, nausea, and vomiting
• Diagnosis involves imaging tests like CT angiography, ultrasound, or MRI to visualize the compression
• The condition is often misdiagnosed due to its similarity to other gastrointestinal disorders, and symptoms may persist in some patients even after surgery
• MALS predominantly affects young to middle-aged women, though the exact cause remains unclear, with theories suggesting anatomical variations or growth changes may contribute to its development

Treatment Approaches

• Conservative approaches like dietary modifications and pain management may be used initially, but are often insufficient for complete symptom relief
• Surgical release of the ligament is the most effective treatment, with or without bypass, and has been rated as usually appropriate with a rating of 8 1
• Supportive measures only, such as analgesics, may be used in some cases, but are generally less effective, with only a third of patients reporting improvement in symptoms 1

Important Considerations

• The decision to reconstruct the celiac artery after surgical release of the ligament remains debatable, with some studies showing no significant difference in symptom relief or reintervention rates between patients who underwent vascular reconstruction and those who did not 1
• The use of percutaneous transluminal angioplasty with stent placement is generally considered a second-line intervention, and is usually not appropriate as a first-line treatment 1

From the Research

Definition and Pathophysiology of Median Arcuate Ligament Syndrome (MALS)

• MALS is a clinical entity characterized by the compression of the celiac artery by the median arcuate ligament, leading to symptoms of foregut ischemia 2, 3, 4, 5, 6.
• The compression of the celiac artery can cause intermittent visceral ischemia, resulting in symptoms such as postprandial epigastric pain, nausea, vomiting, and weight loss 2, 3, 4, 5, 6.
• The pathophysiology of MALS is not fully understood, but it is thought to be related to the extrinsic compression of the celiac artery by the median arcuate ligament, as well as possible neurogenic factors 2, 6.

Diagnosis of MALS

• The diagnosis of MALS is often delayed due to the non-specific nature of the symptoms and the lack of a clear diagnostic criteria 2.
• Imaging studies such as duplex ultrasound, angiography, and computed tomography angiography (CTA) can be used to diagnose MALS, with angiography being the diagnostic standard 2, 3, 4, 6.
• The diagnosis of MALS is typically made by demonstrating compression of the celiac artery on imaging studies, with characteristic respiratory variation 3, 4.

Treatment of MALS

• The primary goal of treatment for MALS is to relieve the compression of the celiac artery, which can be achieved through surgical decompression of the median arcuate ligament 2, 3, 4, 5, 6.
• Surgical techniques for treating MALS include open, laparoscopic, and robotic approaches, with the choice of technique depending on the individual patient's situation 2, 4, 5, 6.
• Endovascular treatment, such as percutaneous transluminal angioplasty and stenting, may be used as an adjuvant procedure in refractory cases with residual stenosis of the celiac trunk 4, 6.