Median arcuate ligament syndrome (Dunbar syndrome)

Abstract

Median arcuate ligament syndrome (MALS) is a rare condition which is due to the compression of celiac trunk by low riding of fibrous attachments of median arcuate ligament and diaphragmatic crura. Technically, MALS is a diagnosis of exclusion, consisting of vague symptoms comprising of postprandial epigastric pain, nausea, vomiting and unexplained weight loss. Different imaging modalities like Doppler ultrasound, computed tomography, magnetic resonance imaging and mesenteric angiogram are helpful to demonstrate celiac axis compression. The goal of treatment is decompression of celiac trunk either by open, laparoscopic or robotic method along with adjuvant interventional procedures like percutaneous transluminal angioplasty (PTA) and stenting. Surgical is the mainstay of treatment. This approach is based on open, laparoscopic or robotic release of compressed ligament along with celiac ganglionectomy and celiac artery revascularization. The role of interventional radiology is limited to angioplasty and stenting to open the stenosis rather than addressing the underlying compression of celiac trunk which has resulted in the symptoms. However, both the diagnosis and therapeutic intervention remains challenging. Extensive evaluation of etiology and pathophysiology of MALS and addressing the same through minimally invasivetechniques may yield best prognosis in future. In this review article, we discuss briefly about the MALS in terms of etiology, diagnosis and its management including the role of interventional radiology.

Trans-Esophageal Echocardiography of the Descending Aorta and Celiac Trunk as an Intraoperative Monitoring for Median Arcuate Ligament Syndrome (MALS) Treatment: Technique Proposal and Two Case Reports

“…Dunbar syndrome, also known as median arcuate ligament syndrome (MALS), is caused by the compression of the celiac artery by the median arcuate ligament (MAL) and the diaphragmatic crura. The MAL is a band of fibrous tissue anteriorly connecting the diaphragmatic crura surrounding the aortic hiatus; the position of the MAL may vary, leading to extrinsic compression of the celiac artery, while an abnormal origin of the celiac artery is less common [1,2]. MALS is characterized by symptoms of foregut ischemia, such as abdominal postprandial or exercise-induced pain, often located in the epigastrium, and unexplained weight loss; other signs and symptoms are nausea and abdominal bruits.…”

“…The most probable hypothesis is that during digestion, an increased demand for intestinal blood flow cannot be supplied by a compressed artery, causing transient intestinal ischemia. Moreover, the chronic compressing of the celiac ganglion MAL may lead to the irritation of sympathetic pain fibers, causing the development of neuropathic pain [1,2]. However, most of the patients with compression of the artery have no symptoms, probably due to the development of collateral circulation which compensates for the insufficient blood flow in the celiac trunk [2,4].…”

“…The treatment is surgical, both open and laparoscopic, with the aim of dissecting and separating the diaphragmatic crura from the celiac axis, thus restoring safe blood flow in the celiac trunk [2,[4][5][6]; endovascular intervention is not suitable because it does not solve the extrinsic compression, and it has thus been proven ineffective [1]. Successful treatment has been confirmed by Doppler ultrasound follow-up, showing the presence of a normal flow in the celiac artery after laparoscopy [7].…”

Gabapentin as a Symptomatic Modifier in Median Arcuate Ligament Syndrome: A Case Report and Assessment of Treatment Modalities

“…Current evidence suggests that duplex abdominal ultrasound during inspiration and deep expiration should be used as an initial assessment for compression of the celiac trunk [10][11][12]. Additional studies that may be useful in diagnosis include computed tomography (CT) angiography and magnetic resonance angiography [4,13]. Once diagnosed, percutaneous celiac plexus/ganglion block should be used to simulate decompression and determine potential surgical candidates [2,14].…”

“…First described by Harjola et al in 1963, the open release of the median arcuate ligament with removal and neurolysis of the celiac plexus/ganglion is the conventional approach to surgical intervention for MALS [15,16]. In recent years, however, laparoscopic decompression and neurolysis have become the accepted standard of care [13]. Not surprisingly, robotic-assisted release and decompression with neurolysis are now showing excellent promise given the ability for enhanced microdissection at the base of the celiac trunk [17,18].…”