Collateral circulation as a possible predictor of symptomatic median arcuate ligament syndrome: a case report

Abstract

Introduction and importance:

Median arcuate ligament syndrome (MALS) is a rare and often underrecognized cause of postprandial abdominal pain resulting from extrinsic compression of the celiac artery by the median arcuate ligament. Diagnosis is challenging due to nonspecific symptoms, overlap with common gastrointestinal conditions, and dynamic anatomical variations.

Case presentation:

A 48-year-old woman with a 2-year history of postprandial epigastric pain underwent multiple evaluations across specialties without a definitive diagnosis. Contrast-enhanced computed tomography ultimately revealed focal celiac artery stenosis with post-stenotic dilatation and well-developed collateral circulation between the common hepatic artery and superior mesenteric artery, confirming MALS as the cause of her symptoms and guiding a multidisciplinary management plan.

Clinical discussion:

MALS results from extrinsic compression of the celiac artery, occasionally compounded by variations in arterial origin, ligament position, or neural plexus involvement. Its nonspecific presentation often mimics common gastrointestinal conditions, making imaging essential for diagnosis. Emerging evidence suggests that prominent collateral circulation in the setting of significant celiac artery stenosis is associated with symptom development, as demonstrated in our case.

Conclusion:

MALS should be considered as a diagnosis of exclusion in patients with persistent postprandial abdominal pain. Recognition of prominent collateral circulation alongside significant celiac artery stenosis may serve as a key indicator of disease severity and symptomatic correlation.

Introduction

Median arcuate ligament syndrome (MALS) is a rare condition caused by external compression of the celiac artery, potentially leading to foregut ischemia^[1^]. Although anatomical narrowing of the celiac artery is relatively frequent, reported in up to 24% of the population, only 3–7% of affected individuals develop clinical symptoms, indicating that arterial compression alone is insufficient to explain the syndrome^[2,3^]. Adaptive collateral circulation plays a crucial role in symptom development and represents an important diagnostic clue^[3^]. Clinical manifestations are typically nonspecific and include postprandial abdominal pain, nausea, vomiting, weight loss, or food avoidance, often leading to delayed diagnosis and repeated investigations^[4^]. While most asymptomatic cases require no intervention, treatment is reserved for patients with persistent, compatible symptoms. In such cases, surgical release of the median arcuate ligament to decompress the celiac axis remains the most commonly employed therapeutic approach^[5^]. Here, we present a case of MALS diagnosed and managed through a multidisciplinary approach. This case report has been prepared in line with the SCARE 2025 checklist and TITAN reporting standards^[6,7^].

HIGHLIGHTS

• Median arcuate ligament syndrome should be considered a diagnosis of exclusion in patients with persistent postprandial abdominal pain.

• Multidisciplinary evaluation combining clinical assessment, imaging, and surgical input is crucial for accurate diagnosis.

• Prominent collateral circulation is a key predictor of symptom correlation in MALS.

• Surgical decompression of the celiac artery can lead to significant symptom improvement.

• These findings are relevant to clinicians managing complex and unexplained abdominal pain syndromes.

Clinical presentation

Patient information

A 48-year-old woman with no significant past medical history presented to our tertiary center with a 2-year history of abdominal pain. The pain was located in the epigastric region and usually started 20–30 minutes after meals. It was associated with nausea and bloating, followed by progressive weight loss. Fatty meals worsened her symptoms, and even small amounts of food triggered nausea. Temporary bowel rest provided partial relief. She had no history of vomiting, abdominal distention, or altered bowel habits, and no family history of similar complaints.

On further questioning, she reported having made multiple visits for persistent abdominal pain. An initial upper gastrointestinal endoscopy showed antral gastritis with a positive test for Helicobacter pylori. She was treated with the standard triple regimen, followed by an additional 6 weeks of proton pump inhibitors. Despite treatment, her symptoms did not improve, leading to repeated consultations with different gastroenterologists.

Over the next 2 years, her symptoms persisted despite multiple investigations and treatments. No clear gastrointestinal cause was identified, which contributed to a delayed diagnosis. By the time she was referred to our center, she had lost approximately 10 kilograms and was increasingly limited by postprandial pain.

Clinical findings

When she presented to our center, she was conscious, cooperative, and fully oriented to time, place, and person. Her vital signs were within normal limits: pulse rate 86 beats/min, blood pressure 120/80 mmHg, respiratory rate 12/min, SpO₂ 98% on room air, and capillary refill time <3 seconds. Abdominal examination revealed no epigastric tenderness or any defects on palpation, with normal bowel sounds. Cardiovascular, respiratory, and neurological systemic examinations were unremarkable.

Diagnostic assessment

Routine laboratory tests, including complete blood count, liver and renal function tests, serum amylase and lipase, stool for H. pylori antigen and inflammatory markers, remained normal. Ultrasound of the abdomen and pelvis, upper gastrointestinal endoscopy, and echocardiography likewise failed to reveal any significant pathology. Given her chronic abdominal pain, a contrast-enhanced computed tomography (CECT) of the abdomen was performed, which revealed severe focal narrowing (>80%) at the origin of the celiac artery, with a characteristic J-shaped configuration (arrow) and associated post-stenotic dilatation of the celiac artery measuring approximately 5.6 mm (Figs. 1 and 2) with a prominent collateral vessel connecting the common hepatic artery and the superior mesenteric artery.

Figure 1.

Sagittal contrast-enhanced computed tomography (CECT) of the abdomen and pelvis demonstrates severe focal narrowing (>80%) at the origin of the celiac artery with a characteristic J-shaped configuration (arrow) and associated post-stenotic dilatation of the celiac artery measuring approximately 5.6 mm.

Figure 2.

Transverse contrast-enhanced computed tomography (CECT) of the abdomen and pelvis demonstrates severe focal narrowing (>80%) at the origin of the celiac artery.

Differential diagnosis

Given her clinical presentation, several differential diagnoses were initially considered, including peptic ulcer disease (PUD), cholelithiasis, and functional gastrointestinal disorders (functional dyspepsia). Other less common possibilities, such as mesenteric ischemia, chronic pancreatitis, and vascular causes – superior mesenteric artery syndrome and MALS – were also considered.

Final diagnosis

A careful, stepwise diagnostic approach was used. Common causes of chronic postprandial abdominal pain were evaluated and excluded. CECT showed narrowing of the celiac artery at its origin, with prominent collateral vessels. These imaging findings, along with her postprandial epigastric pain and progressive weight loss, supported the diagnosis of MALS.

Management

A multidisciplinary approach was adopted, involving the gastroenterology and surgery teams. Her symptoms, imaging findings, and overall clinical condition were carefully reviewed. The team agreed that surgical management was the most appropriate option. Preoperative planning included a discussion of the surgical approach, possible risks, and expected outcomes. The patient then underwent laparoscopic release of the median arcuate ligament to relieve compression of the celiac artery.

Intraoperatively, the right and left diaphragmatic crura were markedly thickened and caused significant external compression of the celiac trunk (Fig. 3). Post-stenotic dilatation of the vessel was noted. The crura were carefully separated, and the median arcuate ligament was divided using bipolar cautery to fully release the compression. Care was taken to preserve nearby vascular and neural structures. Hemostasis was achieved without difficulty. No intraoperative complications occurred, and the patient tolerated the procedure well (Fig. 3).

Figure 3.

Intraoperative image of the celiac artery after release of compression caused by the median arcuate ligament (arrow).

Postoperatively, her recovery was closely monitored by both the surgical and gastroenterology teams, with attention to pain management, nutritional support, and early mobilization (Table 1).

Table 1.

Postoperative course.

Postoperative Day 1: The patient tolerated sips of clear fluids without nausea or vomiting. Vital signs remained stable, and there were no immediate postoperative complications.

Postoperative Day 2: Pain was adequately controlled with oral analgesics. Oral intake was gradually advanced. No gastrointestinal symptoms were noted.

Postoperative Day 3: The patient was ambulating independently and tolerating a regular diet. She remained free of abdominal pain, nausea or food-related anxiety indicating satisfactory postoperative recovery.

Given her steady clinical improvement and stable vital parameters, she was discharged on postoperative day three with advice on gradual dietary advancement and routine outpatient follow-up.

Follow-up and outcome

At the 2-month follow-up, the patient demonstrated significant symptom resolution, tolerated a normal diet, and had gained approximately 1.25 kg of body weight. A repeat CT angiography was recommended to assess postoperative vascular changes; however, the patient declined further imaging due to concerns about additional radiation exposure in the setting of marked clinical improvement. At the 6-month follow-up, a repeat CT angiography was recommended; however, the patient declined due to financial constraints. Given this, Doppler ultrasonography was arranged as an affordable alternative to ensure vascular follow-up. Color Doppler examination demonstrated patent flow in the celiac artery with no sonographic evidence of residual stenosis or hemodynamically significant compression. Clinically, she reported marked improvement in postprandial abdominal pain and appetite at this visit (Fig. 4).

Figure 4.

Follow-up Doppler ultrasonography of the celiac artery. The grayscale image (right panel) demonstrates the abdominal aorta (white arrow) and celiac artery (black arrow), showing the vessel without significant luminal compromise. The color Doppler image (left panel) demonstrates color-flow signals in the abdominal aorta (white arrow) and the celiac artery region (black arrow); the orange/red and blue flow patterns indicate patent vessels with flow in both directions, consistent with a normal branching pattern, indicating maintained celiac artery perfusion on follow-up.

Case discussion

MALS, commonly known as celiac artery compression syndrome or Dunbar’s syndrome, is a rare clinical entity resulting from dynamic compression of the celiac artery by fibrous attachments of the diaphragmatic crura, specifically the median arcuate ligament^[1^]. It most often occurs in young adults between 20 and 40 years of age and shows a clear female predominance, with an estimated incidence of approximately 3–7%^[8^]. About 10–24% of the population have it as a normal anatomical variant^[2^] and, among them, 85% remain clinically asymptomatic^[3^]. The interplay between ligamentous compression, arterial indentation, and irritation of the surrounding neural plexus is considered central to the pathophysiology^[9,10^].

MALS often remains underrecognized, with variable symptoms and unpredictable treatment responses that complicate accurate diagnosis. Typically a diagnosis-of-exclusion, it involves a vague constellation of symptoms, including postprandial epigastric pain (80%), nausea (9.7%), progressive weight loss (48%), and diarrhea (7.5%)^[4^]. The pain is thought to result from ongoing pressure on the celiac ganglion and/or celiac artery, leading to nerve overstimulation and to reduced blood flow that causes foregut ischemia, respectively. In some patients, blood shunted through enlarged collateral vessels may further lower celiac artery perfusion, adding to the symptoms^[11^]. In others, collateral flow from the superior mesenteric artery is sufficient to maintain circulation, leaving them asymptomatic^[12^].

In our case, chronic abdominal pain was initially attributed to common conditions such as PUD, gallstones, and functional dyspepsia. She moved between departments and underwent repeated diagnostic investigations and interventions, yet none of these pointed to a definitive cause. As each likely diagnosis was ruled out, the approach shifted toward considering less common possibilities through a diagnosis-of-exclusion approach. This sequence of shifting yet inconclusive assessments reflects how the nonspecific nature of MALS can mask its true origin, delaying recognition until more familiar explanations have been excluded and a vascular cause is finally considered.

Accurate diagnosis of MALS requires careful correlation of clinical findings and imaging findings, ideally through a multidisciplinary approach. Common diagnostic tools include contrast-enhanced abdominal CT, magnetic resonance angiography, and Doppler ultrasound with a respiratory-variation protocol. Diagnosis is challenging because celiac artery compression is dynamic and varies with respiration, which may lead to underestimation if imaging is performed at an inappropriate phase^[13^]. Additionally, imaging findings commonly associated with MALS, such as the “hooked” or “J-shaped” configuration of the celiac artery, are not specific to pathological compression but may reflect normal anatomical variation^[14^]. Clinical–imaging correlation in MALS is notoriously inconsistent. Some individuals with marked celiac artery narrowing remain completely asymptomatic, while others with only modest or equivocal compression experience significant symptoms^[15,16^].

As highlighted by recent studies, the severity of celiac artery stenosis and the presence and prominence of collateral circulation are key predictors of symptomatic correlation, providing an explanation for why some patients develop significant symptoms while others remain asymptomatic. Although earlier studies proposed that collateral circulation reduces symptoms^[3,17^], a 2024 retrospective study by Xu et al reported contrasting results. In that study, all patients with severe celiac artery stenosis and well-developed collateral vessels developed symptoms consistent with MALS^[15^]. This suggests that even robust collateral circulation may not lead to symptomatic relief. Instead, the authors proposed that the presence of collaterals in the setting of severe celiac artery stenosis may actually serve as a clue toward symptomatic MALS. Our case supports this observation, as significant celiac artery stenosis was accompanied by prominent collateral circulation and clear postprandial symptoms. The coexistence of well-developed collaterals with a significant symptomatic profile therefore pointed toward symptomatic MALS as a likely cause of abdominal pain in a setting of diagnostic uncertainty.

This case puts forward the concept that, in situations of diagnostic uncertainty, careful correlation of clinical symptoms with the degree of stenosis and the extent of collateral circulation can help anticipate the likely diagnosis. Surgical and endovascular strategies for MALS range from isolated division of the median arcuate ligament (with or without celiac ganglionectomy) performed via open, laparoscopic, or robotic approaches to adjunctive vascular procedures such as endovascular angioplasty/stenting and formal arterial reconstruction or bypass when flow remains inadequate after decompression^[18–20^]. Recent reviews and multicenter studies show most patients improve symptomatically after intervention; however, a substantial minority may later require reintervention^[21,22^]. About 90% of patients remained pain-free at 1-year follow-up under a standardized management protocol^[19,20^]. Various studies show laparoscopic release offers shorter hospital stays and lower early morbidity than open surgery, whereas arterial revascularization remains an adjunct for patients with severe residual celiac stenosis^[22^]. Endovascular stenting, often used after decompression when residual stenosis persists or as a bridge in staged management, is less invasive but may fail if external compression is not fully relieved^[18^]. Hybrid approaches combining laparoscopic release with endovascular intervention have been shown to be feasible and safe, particularly for patients with demonstrable persistent hemodynamic compromise or limited collateral circulation^[5^].

Conclusion

This case emphasizes the importance of considering MALS as a diagnosis of exclusion in patients with persistent, unexplained postprandial abdominal pain. The identification of significant celiac artery compression, together with prominent collateral circulation, was central to establishing the diagnosis and reflected disease severity. These findings support emerging evidence that collateral vessels are not merely adaptive but may also correlate with symptomatic burden.

Limitation

While this case supports a possible association between collateral circulation and symptomatic MALS, the absence of postoperative CT angiography and the potential contribution of celiac plexus disruption to symptom relief prevent definitive conclusions. Further studies with larger cohorts and standardized postoperative vascular imaging are required to validate this hypothesis and clarify the role of collateral circulation in symptom generation and disease severity.

Ethical approval

Ethical approval was not required for the study involving humans, in accordance with local legislation and institutional requirements. Written informed consent was obtained from all patients for publication of the data included in this article.

Consent

Written informed consent was obtained from the patient for publication and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Sources of funding

The author(s) declare that financial support was not received for the research, authorship, and/or publication of this article.

Author contributions

P.W.: Manuscript preparation, manuscript review, literature review, and editing. B.B..: Manuscript preparation, manuscript review, literature review, and editing. S.S.: Case management, literature review, and editing. R.B.: Case management, literature review, and editing. R.J.: Literature review and editing.

Conflicts of interest disclosure

The authors declare that the research was conducted in the absence of any commercial or financial relationships.

Research registration unique identifying number (UIN)

Not applicable.

Guarantor

Dr. Sujan Shrestha.

Provenance and peer review

Not commissioned; internally peer-reviewed.

Data availability statement

The raw data supporting the conclusions of this article will be made available by the authors without undue reservation.

Declaration on generative AI and AI-assisted technologies

During the preparation of this work, the authors used ChatGPT to polish the language and make it more reader-friendly. After using this tool or service, the authors reviewed and edited the content as needed and take full responsibility for the published article.

Acknowledgements

Not applicable.