medicine Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care pract ...

, the median arcuate ligament syndrome (MALS, also known as celiac artery compression syndrome, celiac axis syndrome, celiac trunk compression syndrome or Dunbar syndrome) is a rare condition characterized by

abdominal pain Abdominal pain, also known as a stomach ache, is a symptom Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than ...

attributed to compression of the

celiac artery The celiac () artery (also spelled ''coeliac''), also known as the celiac trunk or truncus coeliacus, is the first major branch of the abdominal aorta. It is about 1.25 cm in length. Branching from the aorta at thoracic vertebra 12 (T12) in ...

and the

celiac ganglia The celiac ganglia or coeliac ganglia are two large irregularly shaped masses of nerve tissue in the upper abdomen. Part of the sympathetic subdivision of the autonomic nervous system (ANS), the two celiac ganglia are the largest ganglia in ...

by the

median arcuate ligament The median arcuate ligament is a ligament under the diaphragm that connects the right and left crura of diaphragm. Structure The median arcuate ligament is formed by the right and left crura of the diaphragm. The crura connect to form an ar ...

. The abdominal pain may be related to meals, may be accompanied by weight loss, and may be associated with an abdominal

bruit Bruit, also called vascular murmur, is the abnormal sound generated by turbulent flow of blood in an artery due to either an area of partial obstruction or a localized high rate of blood flow through an unobstructed artery. The bruit may be hear ...

heard by a clinician. The diagnosis of MALS is one of exclusion, as many healthy patients demonstrate some degree of celiac artery compression in the absence of symptoms. Consequently, a diagnosis of MALS is typically only entertained after more common conditions have been ruled out. Once suspected, screening for MALS can be done with

ultrasonography Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies fr ...

and confirmed with computed tomography (CT) or

magnetic resonance Magnetic resonance is a process by which a physical excitation (resonance) is set up via magnetism. This process was used to develop magnetic resonance imaging and Nuclear magnetic resonance spectroscopy technology. It is also being used to ...

(MR)

angiography Angiography or arteriography is a medical imaging technique used to visualize the inside, or lumen, of blood vessels and organs of the body, with particular interest in the arteries, veins, and the heart chambers. Modern angiography is performe ...

. Treatment is generally surgical, the mainstay being

open Open or OPEN may refer to: Music * Open (band), Australian pop/rock band * The Open (band), English indie rock band * ''Open'' (Blues Image album), 1969 * ''Open'' (Gotthard album), 1999 * ''Open'' (Cowboy Junkies album), 2001 * ''Open'' (YF ...

laparoscopic Laparoscopy () is an operation performed in the abdomen or pelvis using small incisions (usually 0.5–1.5 cm) with the aid of a camera. The laparoscope aids diagnosis or therapeutic interventions with a few small cuts in the abdomen.Medli ...

division, or separation, of the median arcuate ligament combined with removal of the

. The majority of patients benefit from surgical intervention. Poorer responses to treatment tend to occur in patients of older age, those with a

psychiatric condition A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitti ...

or who use alcohol, have abdominal pain unrelated to meals, or who have not experienced weight loss.

Signs and symptoms

Patients with MALS reportedly experience

, particularly in the

epigastrium In anatomy, the epigastrium (or epigastric region) is the upper central region of the abdomen. It is located between the costal margins and the subcostal plane. Pain may be referred to the epigastrium from damage to structures derived from the fo ...

, which may be associated with eating and which may result in

anorexia Anorexia nervosa, often referred to simply as anorexia, is an eating disorder characterized by low weight, food restriction, body image disturbance, fear of gaining weight, and an overpowering desire to be thin. ''Anorexia'' is a term of Gre ...

and

weight loss Weight loss, in the context of medicine, health, or physical fitness, refers to a reduction of the total body mass, by a mean loss of fluid, body fat (adipose tissue), or lean mass (namely bone mineral deposits, muscle, tendon, and other conn ...

. The pain can be in the left or right side, but usually where the ribs meet. Other signs are persistent nausea, lassitude (especially after a heavy meal) and exercise intolerance. Diarrhea is a common symptom, some experience constipation. While some experience vomiting, not everyone does. Exercise or certain postures can aggravate the symptoms. Occasionally,

physical examination In a physical examination, medical examination, or clinical examination, a medical practitioner examines a patient for any possible medical signs or symptoms of a medical condition. It generally consists of a series of questions about the patien ...

reveals an abdominal

in the mid-epigastrium. Complications of MALS result from chronic compression of the celiac artery. They include

gastroparesis Gastroparesis (gastro- from Ancient Greek γαστήρ – gaster, "stomach"; and -paresis, πάρεσις – "partial paralysis"), also called delayed gastric emptying, is a medical disorder consisting of weak muscular contractions (peristalsis) ...

and

aneurysm An aneurysm is an outward bulging, likened to a bubble or balloon, caused by a localized, abnormal, weak spot on a blood vessel wall. Aneurysms may be a result of a hereditary condition or an acquired disease. Aneurysms can also be a nidus (s ...

of the superior and inferior pancreaticoduodenal arteries.

Anatomy

Side views (sagittal plane) of the descending aorta and two of its branches, the

celiac trunk The celiac () artery (also spelled ''coeliac''), also known as the celiac trunk or truncus coeliacus, is the first major branch of the abdominal aorta. It is about 1.25 cm in length. Branching from the aorta at thoracic vertebra 12 (T12) i ...

and

superior mesenteric artery In human anatomy, the superior mesenteric artery (SMA) is an artery which arises from the anterior surface of the abdominal aorta, just inferior to the origin of the celiac trunk, and supplies blood to the intestine from the lower part of the ...

, demonstrate normal and MALS anatomy. ''Left'' The

is normally several millimeters to centimeters superior to the origin of the

. ''Right'' In MALS, the ligament is anterior, rather than superior, to the celiac artery, resulting in compression of the vessel and a characteristic hook-shaped contour.

The

is a

ligament A ligament is the fibrous connective tissue that connects bones to other bones. It is also known as ''articular ligament'', ''articular larua'', ''fibrous ligament'', or ''true ligament''. Other ligaments in the body include the: * Peritoneal li ...

formed at the base of the diaphragm where the left and right diaphragmatic crura join near the 12th

thoracic vertebra In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, there are twelve thoracic vertebrae and they are intermediate in size between the cervical ...

. This fibrous arch forms the anterior aspect of the

aortic hiatus The aortic hiatus is a hole in the diaphragm. It is the lowest and most posterior of the large apertures. It is located approximately at the level of the twelfth thoracic vertebra (T12). Structure Strictly speaking, it is not an aperture in th ...

, through which the

aorta The aorta ( ) is the main and largest artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries (the common iliac arteries). The aorta distributes ...

thoracic duct In human anatomy, the thoracic duct is the larger of the two lymph ducts of the lymphatic system. It is also known as the ''left lymphatic duct'', ''alimentary duct'', ''chyliferous duct'', and ''Van Hoorne's canal''. The other duct is the right ...

, and

azygos vein The azygos vein is a vein running up the right side of the thoracic vertebral column draining itself towards the superior vena cava. It connects the systems of superior vena cava and inferior vena cava and can provide an alternative path for blood ...

pass. The median arcuate ligament usually comes into contact with the aorta above the branch point of the

. However, in up to one quarter of normal individuals, the median arcuate ligament passes in front of the celiac artery, compressing the celiac artery and nearby structures such as the

. In some of these individuals, this compression is pathologic and leads to the median arcuate ligament syndrome.

Mechanism

Several theories attempt to explain the origin of pain caused by compression of the celiac artery. One proposes that compression of the celiac artery causes

ischemia Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems wi ...

, or decreased blood flow, to abdominal organs, leading to pain. Another hypothesizes that there is compression not only of the celiac artery but also of the celiac ganglia, and that pain results from compression of the latter.

Diagnosis

Median arcuate ligament syndrome is a diagnosis of exclusion. That is, the diagnosis of MALS is generally considered only after patients have undergone an extensive evaluation of their

gastrointestinal tract The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organ (biology), organs of the digestive syste ...

including

upper endoscopy Esophagogastroduodenoscopy (EGD) or oesophagogastroduodenoscopy (OGD), also called by various other names, is a diagnostic endoscopic procedure that visualizes the upper part of the gastrointestinal tract down to the duodenum. It is considered ...

colonoscopy Colonoscopy () or coloscopy () is the endoscopic examination of the large bowel and the distal part of the small bowel with a CCD camera or a fiber optic camera on a flexible tube passed through the anus. It can provide a visual diagnosis (''e. ...

, and evaluation for

gallbladder disease Gallbladder diseases are diseases involving the gallbladder and is closely linked to biliary disease, with the most common cause being gallstones (cholelithiasis). The gallbladder is designed to aid in the digestion of fats by concentrating and ...

and

gastroesophageal reflux disease Gastroesophageal reflux disease (GERD) or gastro-oesophageal reflux disease (GORD) is one of the upper gastrointestinal chronic diseases where stomach content persistently and regularly flows up into the esophagus, resulting in symptoms and/ ...

(GERD). The diagnosis of MALS relies on a combination of clinical features and findings on

medical imaging Medical imaging is the technique and process of imaging the interior of a body for clinical analysis and medical intervention, as well as visual representation of the function of some organs or tissues (physiology). Medical imaging seeks to rev ...

. Clinical features include those signs and symptoms mentioned above; classically, MALS involves a triad of abdominal pain after eating, weight loss, and an abdominal

, although the classic triad is found in only a minority of individuals that carry a MALS diagnosis. Diagnostic imaging for MALS is divided into screening and confirmatory tests. A reasonable screening test for patients with suspected MALS is

duplex ultrasonography Doppler ultrasonography is medical ultrasonography that employs the Doppler effect to perform imaging of the movement of tissues and body fluids (usually blood), and their relative velocity to the probe. By calculating the frequency shift of a ...

to measure blood flow through the

. Peak systolic velocities greater than 200 cm/s are suggestive of celiac artery stenosis associated with MALS. Coeliacus compression cta

Further evaluation and confirmation can be obtained via

to investigate the anatomy of the celiac artery. Historically, conventional angiography was used, although this has been largely replaced by less invasive techniques such as computed tomography (CT) and

(MR) angiography. Because it provides better visualization of intra-abdominal structures, CT angiography is preferred to MR angiography in this setting. The findings of focal narrowing of the proximal celiac artery with poststenotic dilatation, indentation on the superior aspect of the celiac artery, and a hook-shaped contour of the celiac artery support a diagnosis of MALS. These imaging features are exaggerated on expiration, even in normal asymptomatic individuals without the syndrome. Proximal celiac artery stenosis with poststenotic dilatation can be seen in other conditions affecting the celiac artery. The hook-shaped contour of the celiac artery is characteristic of the anatomy in MALS and helps distinguish it from other causes of celiac artery stenosis such as

atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis in which the wall of the artery develops abnormalities, called lesions. These lesions may lead to narrowing due to the buildup of atheroma, atheromatous plaque. At onset there are usu ...

. This hooked contour is not entirely specific for MALS however, given that 10–24% of normal asymptomatic individuals have this anatomy.

Treatment

Decompression of the celiac artery is the general approach to treatment of MALS. The mainstay of treatment involves an

surgery Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...

approaches to divide, or separate, the median arcuate ligament to relieve the compression of the celiac artery. This is combined with removal of the

and evaluation of blood flow through the celiac artery, for example by intraoperative duplex ultrasound. If blood flow is poor, celiac artery

revascularization In medical and surgical therapy, revascularization is the restoration of perfusion to a body part or organ that has had ischemia. It is typically accomplished by surgical means. Vascular bypass and angioplasty are the two primary means of reva ...

is usually attempted; methods of revascularization include aortoceliac bypass, patch angioplasty, and others. In recent, a laparoscopic approach used to achieve celiac artery decompression; however, should the celiac artery require revascularization, the procedure would require conversion to an open approach.

Endovascular Interventional radiology (IR) is a medical specialty that performs various minimally-invasive procedures using medical imaging guidance, such as Fluoroscopy, x-ray fluoroscopy, CT scan, computed tomography, magnetic resonance imaging, or ultraso ...

methods such as

percutaneous transluminal angioplasty Angioplasty, is also known as balloon angioplasty and percutaneous transluminal angioplasty (PTA), is a minimally invasive endovascular procedure used to widen narrowed or obstructed arteries or veins, typically to treat arterial atheroscler ...

(PTA) have been used in patients who have failed open and/or laparoscopic intervention. PTA alone, without decompression of the celiac artery, may not be of benefit.

Prognosis

There are few studies of the long-term outcomes of patients treated for MALS. According to Duncan, the largest and more relevant late outcomes data come from a study of 51 patients who underwent open surgical treatment for MALS, 44 of whom were available for long-term follow-up at an average of nine years following therapy. The investigators reported that among patients who underwent celiac artery decompression and revascularization, 75% remained asymptomatic at follow-up. In this study, predictors of favorable outcome included: * Age from 40 to 60 years * Lack of

or alcohol use * Abdominal pain that was worse after meals * Weight loss greater than 20 lb (9.1 kg)

Epidemiology

It is estimated that in 10–24% of normal, asymptomatic individuals the median arcuate ligament crosses in front of (anterior to) the celiac artery, causing some degree of compression. Approximately 1% of these individuals exhibit severe compression associated with symptoms of MALS. The syndrome most commonly affects individuals between 20 and 40 years old, and is more common in women, particularly thin women.

History

Celiac artery compression was first observed by Benjamin Lipshutz in 1917. MALS was first described by Pekka-Tapani Harjola in 1963 and subsequently by J. David Dunbar and Samuel Marable in 1965. It has also been called Harjola-Marable syndrome and Marable syndrome.

References

External links

{{Medical resources , eMedicineSubj = article , eMedicineTopic = 188618 , ICD9 = {{ICD9, 447.4 , ICD10 = {{ICD10, I, 77, 4, i, 70 , SNOMED CT = 9250002 Diseases of arteries, arterioles and capillaries Syndromes affecting the vascular system