Treatment of Median Arcuate Ligament Syndrome Via Traditional and Robotic Techniques

Abstract

Median arcuate ligament syndrome (MALS) is a rare entity characterized by extrinsic compression of the celiac artery and symptoms of postprandial epigastric pain, nausea, vomiting, and weight loss mimicking mesenteric ischemia. We present two patients diagnosed with MALS, the first treated with an open laparotomy by a vascular surgeon and the second using a robot assisted laparoscopic approach by a general surgeon with a vascular surgeon on standby. This is the second ever report of this approach. Both patients recovered without complications and experienced resolution of their symptoms. A discussion of the pathophysiology, literature review, and multispecialty treatment approach are presented.

Introduction

Median arcuate ligament syndrome (MALS), also known as celiac artery compression syndrome, celiac axis syndrome or Dunbar syndrome, is often misdiagnosed due to its relative scarcity.¹ The classic triad of post-prandial abdominal pain, weight loss and epigastric bruit is likely to be incomplete. Due to a wide differential diagnosis, including peptic ulcer, gallbladder disease, appendicitis, IBD etc., most patients will have undergone multiple radiologic investigations or procedures including esophagoduodenoscopy or even diagnostic laparoscopy.¹ Once diagnosed by magnetic resonance angiography (MRA) or CT angiography (CTA) the symptomatic patient usually requires surgery. While the traditional open approach still dominates, minimally invasive techniques are increasing in frequency.²

We present two patients with MALS, one treated via open laparotomy and the other utilizing robotic technology, the second reported in the Western literature.

Case Report

Case 1

A 62-year-old previously healthy woman presented to the emergency department with abdominal pain, indigestion and hot flashes. The patient described postprandial pain without relief from antacids. The physical examination was significant for tenderness to palpation of the abdomen, without peritoneal signs or bruit. Further questioning revealed a 2.5 kg weight loss over the previous two weeks. Abdominal CT scan, electrocardiogram and laboratory values were unremarkable. The patient returned to the ED two days later with epigastric pain radiating to the left sternal area alleviated with nitroglycerin. Cardiac workup including coronary angiogram was normal. Later, a gastroenterologist ordered an MRA that identified a near obstruction of the celiac artery (Figure 1) with the typical “hook” deformity of MALS. After referral to vascular surgery, duplex ultrasound confirmed severe stenosis of the celiac artery with elevated velocities of 336 cm/s (normal <250) in the supine position.

Figure 1.

62-year-old woman with a “hook” deformity of the celiac artery caused by the median arcuate ligament.

Because the patient had previously undergone a midline laparotomy for complicated appendicitis, an open approach was undertaken. Celiac trunk vessels were identified and traced to the celiac trunk where the celiac artery was severely compressed by the MAL. The taut ligamentous tissue stretched across the cephalad portion of the celiac artery was divided and excised. Tissue extending one centimeter from the celiac trunk was circumferentially excised ensuring removal of all compressive tissue. Meticulous care was taken to remove the surrounding ganglia. Intraoperative ultrasound showed post release velocity of 180 cm/s. The patient did well post operatively, was discharged on post-operative day four and one month later had near complete resolution of her symptoms.

Case 2

A 49-year-old woman with a medical history of gastritis, colonicpolyps, and hypercholesterolemia was referred to a general surgeon with a 10-week history of postprandial epigastric pain and 2 kg weight loss. Initial management with proton pump inhibitors provided symptomatic relief. She denied any hematochezia, hematemesis, melena, nausea, vomiting, orabnormal bowel habits. After finding an abdominal bruit on physical exam, gastroenterologist ordered duplex ultrasound, MRA and CTA of the abdomen revealing a celiac artery flow velocity of >300 cm/s with poststenotic dilation and increased blood flow on expiration (Figure 2).

Figure 2.

Compression of celiac artery by the median arcuate ligament in a 49-year-old woman.

A general surgeon, with a vascular surgeon on standby, undertook a robot assisted laparoscopic approach. Similar to the open technique, the celiac artery was identified and the strictures about the median arcuate ligament and surrounding nerve tissue were circumferentially cleared using hook cautery. Intraoperative laparoscopic ultrasound confirmed the location of the celiac artery prior to release and confirmed adequacy of the treatment post release. The patient was discharged the following day without complications. On follow up, after two weeks, the patient had complete resolution of her symptoms with normal flow velocity of the celiac artery (184 cm/s).

Discussion

MALS occurs most frequently in females aged 40 to 60 with duration of symptoms ranging from 3 months to 10 years. Common symptoms include nausea, vomiting, and postprandial epigastric pain leading to an aversion of food and resulting 5–10 kg weight loss.¹ Epigastric bruits increasing with expiration are reported in 83% of cases and may be the only clinical sign. Nonetheless, it is important to note that epigastric bruits can be found in 30% of normal healthy adults.^1,3

The etiology of MALS remains unknown but a case report of monozygotic twins suggests a congenital origin.⁴ Whether the pathophysiology is primarily vascular or neuropathic origin remains undetermined.³ Isolated vascular compression of the celiac artery as the sole etiologic factor seems unlikely. First, in 10%–24% of the population the MAL can cause asymptomatic compression.⁵ Second, collateral circulation by the superior mesenteric artery provides adequate blood supply; therefore, postprandial abdominal pain should not be expected with celiac artery compression alone.

The cause of MALS is likely multifactorial, including compressive effects on the celiac artery and surrounding neurogenic structures. In celiac artery compression, it has been noted that either the celiac artery is located slightly higher or the MAL is located lower than expected.⁶ In a large series, significantly higher symptomatic relief was achieved through combined release of the MAL and revascularization.⁷ If celiac artery compression alone is corrected, evidence suggests up to 53% will be asymptomatic on long-term follow up.⁷ Combined release and revascularization however increases the long-term success to 79%.⁷ Therefore some patients may require additional revascularization procedures such as mesenteric artery stenting or bypass to provide long-term symptomatic relief. Since delay of revascularization is unlikely to adversely affect outcome, most choose ligament release first, followed by revascularization via stenting or bypass if symptoms persist. Endovascular celiac artery stenting alone without release of the ligament is discouraged because of clinical failure and recurrent stenosis.⁸

The series also demonstrated resolution of postprandial pain in 81% of patients. Symptom resolution was more likely in those aged 40 to 60 and weight loss greater than 10 kilograms.⁷ Patients with atypical pain patterns, periods of remission, age over 60, history of psychiatric or alcohol abuse, or weight loss under 10 kg experienced less symptom resolution after ligament release.⁷

While historically MALS was treated primarily by vascular surgeons, the shift towards less invasive procedures has allowed general surgeons with training in minimally invasive surgery to operate more. Nonetheless, injury to the celiac artery and bleeding is a serious risk and the operating team must be prepared to intervene.⁹ In a case series of 10 patients undergoing minimally invasive repair, 8 were converted to open due to bleeding from either the aorta or a major vessel requiring the assistance of a vascular surgeon.¹⁰ Therefore, close cooperation between the general surgeon and a vascular surgeon is imperative unless the general surgeon feels comfortable dealing with potential vascular complications.

The cases presented illustrate two extremely different surgical approaches. Since the initial case report in 2007, there have been no other cases reported in literature of a robot assisted laparoscopic approach.¹¹ The benefits of a laparoscopic approach include faster recovery, discharge, and less postoperative pain.¹⁰ Compared to laparoscopic procedures the enhanced three-dimensional perception of robotics offers improved dexterity and control to divide the ligament and maneuver around the celiac artery.

Both cases illustrate how the diagnosis was reached only after multiple imaging and diagnostic procedures ruled out more common pathology and highlights how the rarity of MALS is complicated by non-specific clinical patient presentation. By combining the diagnostic skills of the vascular expert and the laparoscopic skills of the general surgeon, the precise diagnosis can be reached and treatment delivered by less invasive techniques optimally and safely. If symptoms persist, revascularization of the celiac artery by either endovascular stenting or bypass can be considered as secondary procedures.

Conflict of Interest

None of the authors identify any conflict of interest.