Editing Median arcuate ligament syndrome

Compression of the coeliac artery by the median arcuate ligament

* Also known as coeliac artery     compression syndrome and Dunbar syndrome

== Anatomy ==

* MAL formed from the diaphragm     - composed of the fibrous edge of the diaphragmatic crura, crossing the     aorta at the level of the coeliac artery and extending laterally toward     the suspensory ligament of the fourth part of the duodenum
* MAL is normally just above     the coeliac artery take-off
* Compression of the celiac     artery by the median arcuate ligament is accentuated during expiration (as     the median arcuate ligament moves cranially), and relieved during     inspiration

== Pathophysiology ==

* Multiple theories exist as to     the reason for pain
** Increased blood demand      through a compressed coeliac artery - but mucosal oxygen delivery does      not correlate with either degree of compression or clinical findings, and      MALS is not associated with gastric ischaemia/necrosis on endoscopy
** Pain could be from midgut      ischaemia, after that blood is stolen by collaterals
** Pain could be from      overstimulation of the coeliac plexus with subsequent splanchnic      vasoconstriction and ischaemia

== Epidemiology ==

* Up to 24% of the population     may have some degree of MAL compression
* Less than 1% of the patients     with compression are symptomatic
* Occurs 2nd to 6th decades of     life, mostly 30-50yo
* F:M 3:1

== Presentation: ==

* Common:
** Post-prandial and      exercise-induced epigastric pain
** Nausea/vomiting
** Food fear/weight loss
** Bruit, particularly with      expiration
* Uncommon:
** Autonomic dysfunction
** Fibromyalgia
** POTS
** Coeliac bruit with maximal      expiration
* Many patients have had     extensive workup with multiple investigations and procedures before this     diagnosis is arrived at

== Work-up ==

* Some authors suggest routine     CT, biliary US, gastroscopy and maybe HIDA scan prior to intervention for     MALS, with abnormalities being treated
* If nothing found, perform CA     duplex, proceeding to CTA if abnormalities
* Proceed to intervention with     typical history and supportive imaging with no alternative diagnosis

== Imaging ==

* DUS can be good because it's     easy to apply dynamic techniques, but operator-dependent
** Look for turbulent flow with      increased PSV on expiration, which normalises with inspiration
** PSV should be >200cm/s to      consider the diagnosis
** Can also see abnormal      origins of the coeliac and SMA, post-stenotic bulbar dilatation, and      reverse flow in hepatic artery
** Gruber criteria: CA end      diastolic velocity >350cm/s, 210% change in pulse volume amplitude      during respiration, and a CA deflection angle of 50 degrees
* CTA
** Asymmetric focal narrowing      of the proximal coeliac axis with post-stenotic dilation
** Narrowing accentuated on      expiration, relieved on inspiration
** Increased collaterals in CA      distribution

== Management ==

* Endovascular
** Won't be successful unless      the MAL is also released - PTA/stenting is contra-indicated in presence      MALS, as the stent will get crushed or obstructed
* Laparoscopic
** Standard 5-port technique
**
** Retract liver cephalad and      enter lesser sac
** Expose left gastric artery      and coronary vein, then retract to right to see towards the CA origin
** Dissect CHA, left gastric      artery and splenic artery 4cm distal to the CA bifurcation in order to      divide all the neurovascular bundles surrounding the three vessels
** Crural and MAL fibres      divided from the overlying aorta using hook cautery
** Extend aortic dissection 5cm      proximal to the origin of CA to ensure complete division of the coeliac      plexus
** Dissection extends to the      prevertebral fascia on the right of the aorta and to the suspensory      ligament of D4 on the left, with all ganglionic fibres being divided

== Results ==

* Nearly 30% of patients will     remain symptomatic post-op, with some requiring further endovascular     interventions to the CA trunk


[[Category:UGIS]]