By W. Michael Park, MD; Kevin M. El-Hayek, MD; and Matthew Kroh, MD
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Ms. A is a 28-year-old woman who had upper abdominal pain of 18 months’ duration and an associated 70-pound weight loss. The pain was intense and triggered by eating.
She underwent an extensive gastroenterology workup — including esophagogastroduodenoscopy, endoscopic ultrasound, capsule enteroscopy, hepatobiliary iminodiacetic acid (HIDA) scan, CT and MRI — which suggested compression of her celiac axis by her median arcuate ligament. Vascular ultrasound confirmed this and showed velocities in the celiac axis of 450 cm/sec without inspiration and 215 cm/sec with inspiration. Flows were normal in the superior mesenteric artery.
Vascular surgery and general surgery consultation confirmed that she would benefit from laparoscopic release of the median arcuate ligament. Surgery was performed by the combined team, and a full release of the ligament (Figures 1 and 2) and lysis of the celiac plexus were performed. She recovered well and was discharged on postoperative day 2, tolerating a regular diet without pain for the first time in over a year.
MALS: Often the end of a long diagnostic road
For many patients, median arcuate ligament syndrome (MALS) is the final diagnosis of a medical journey. It usually starts with abdominal pain that soon becomes incapacitating. Food may trigger or exacerbate it, and meals are avoided, resulting in weight loss. Some will lose more than 50 pounds, but average loss is about 20 pounds. Lying facedown or crouching will sometimes relieve the pain, which occurs in the upper abdomen.
Because of the pain’s location, coincidence with eating and associated weight loss, an extensive workup including blood tests and wide-ranging imaging studies (radiographic, magnetic resonance, ultrasound, nuclear and endoscopic) is typically done. Not infrequently, the gallbladder is removed without pain relief. A referral is made when compression of the celiac axis by the median arcuate ligament of the diaphragm is diagnosed.
Why MALS is controversial
Controversy surrounds this diagnosis because of the lack of proved mechanism. Some surgeons do not believe this malady exists, noting justifiably that for the great majority of patients without atherosclerotic occlusive disease, intermittent occlusion of the celiac axis should not cause mesenteric ischemia because of the usually excellent collateral circulation present between the celiac axis and superior mesenteric artery beds.
A diagnosis of exclusion
The evidence lies primarily in the relief patients get from release of the median arcuate ligament when more common and potentially deadly diagnoses are ruled out. MALS is therefore a diagnosis of exclusion. This means many more common diagnoses (gastroesophageal reflux disease, gastritis, gastroparesis, hepatobiliary disease, and disorders of the pancreas, liver, gallbladder, spleen and intestine) are considered and worked up before the patient is referred to a center that treats MALS.
MALS shares some characteristics with mesenteric ischemia, but it affects a younger population, generally women. It is related to compression of the celiac axis by the median arcuate ligament of the diaphragm, resulting in stenosis of the celiac axis. The pain may be due to regional ischemia brought on by increases in postprandial demand, but it may also result from pathologic compression, inflammation and fibrosis of the nerve fibers of the celiac plexus. Sometimes a celiac plexus block is used to help refine the diagnosis in cases that do not present with classic symptoms.
Weighing surgical risks and outcomes
The decision to proceed with surgery balances risk of harm against likelihood of success. The latter is related to the presence of weight loss, being younger to middle age, the absence of significant atherosclerosis and the absence of significant foregut pathology. The risk of conversion to open repair for bleeding or other reasons is about 5 percent.
When laparoscopic release alone fails to relieve symptoms, treatment of any residual stenosis involving the celiac axis is considered. As we recently reported, the vast majority of patients report improvement in pain after treatment.
Traditionally, open surgical release of the median arcuate ligament and, if necessary, reconstruction of the celiac axis were the gold standard, but laparoscopic release and subsequent endovascular repair, if necessary, offer a minimally invasive set of options for potential relief.
At Cleveland Clinic, a multidisciplinary team including members from vascular surgery and general surgery is engaged in the evaluation and treatment of MALS. This collaboration and combined institutional experience enhance the safety and outcomes of patients with this relatively rare but debilitating disease.