Anecdotally, I’ve seen more publications recently regarding median arcuate ligament syndrome (MALS). A recent study (JP Moak et al. J Pediatr 2021; 231: 141-147. Median Arcuate Ligament Syndrome with Orthostatic Intolerance: Intermediate-Term Outcomes following Surgical Intervention) prospectively examines the outcomes in patients with MALS and with orthostatic intolerance (OI).
Background: MALS is generally considered after other more common conditions. Typical symptoms include abdominal pain after eating or exercise and often weight loss due to fear of eating. The pain is often positional and may improve with leaning forward. The diagnostic finding of celiac artery compression may be identified in many healthy individuals (10-24% of population); thus, only severe compression, which is seen in a small number, can result in symptomatic MALS.
In this study, the key findings:
- 31 patients with both MALS and OI were identified from 2014-2019. Median f/u after surgery was 22 months.
- Based on questionnaires, gastrointestinal symptoms of abdominal pain, nausea, and vomiting improved in 63% (P = .007), 53% (P = .040), and 62% (P = .014) of patients, respectively.
- Based on questionnaires, cardiovascular symptoms of dizziness, syncope, chest pain, and palpitations improved in 45% (P = not significant), 50% (P = not significant), 54% (P = .043), and 54% (P = .037) of patients, respectively.
- Importantly, the authors could not demonstrate a “statistical relationship between a postoperative decrease in celiac artery Doppler velocity and improvement in clinical symptoms.”
- In an effort to gauge for a potential post-surgical placebo effect, the authors determined the degree of improvement in musculoskeletal symptoms. There was a 24% improvement which was much less than the improvement in GI symptoms.
One useful feature of this article is that the authors explicitly state how they arrive at the diagnosis of MALS. They start with an abdominal ultrasound with doppler. Criteria for suspected MALS include supine celiac artery peak systolic velocity of >300 cm/s, celiac artery/aoritic peak systolic ratio of >3:1, neutral position celiac artery peak systolic velocity of >200 cm/s, and a change in the celiac artery deflection angle of >50 degrees between inspiration and expiration. If ultrasound is abnormal, the authors obtained an enhanced CT to image inspiratory and expiratory changes in the celiac artery deflection angle, the area of stenosis, poststenotic dilation, and the collateral blood vessels. If there are discrepancies between U/S and CT, a celiac arterial angiogram is obtained.
The authors conclude that there “were minimal improvements in neurologic or psychological symptoms after MALS surgery, despite their common occurrence among patients with POTS.”
My take: This study, in agreement with others, showed that about 60% had improvement in GI symptoms including pain, nausea and vomiting. In those with OI, most continued with impaired health. Overall, MALS as a clinical entity remains a ‘needle in a haystack.’
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