Takayasu’s Arteritis Driven Median Arcuate Ligament Syndrome: Unusual Symptoms Demand Unusual Solutions

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The patient is a young woman from overseas who was referred to the clinic for abdominal and chest pain that persisted after diagnosis and treatment of Takayasu’s Arteritis affecting her visceral (middle) aorta. A year prior to presentation, she had been having severe abdominal pain, 30 pound weight loss, and weakness. Laboratory findings included elevated inflammatory markers. CT scan showed inflammation around her celiac axis and superior mesenteric artery. She was treated with prednisone but only responded ultimately to immunosuppressives. Her pain remitted for a while and she regained weight and strength, but eventually in the months prior to consultation, symptoms of postprandial abdominal pain and nausea set in with concomitant constant midsternal chest pain which at times was incapacitating.

Examination was remarkable for a well nourished young woman in distress with epigastric tenderness. Inflammatory markers were normal and she was on methotrexate and tocilizumab. CTA (above) and duplex showed severe stenoses affecting the origins of the celiac axis and superior mesenteric artery. A composite of the centerlines through these showed the arteries to be critically narrowed at their origins (below), along with a mild to moderate stenosis of the aorta (above). No active inflammation could be seen.

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The anterior view of the 3DVR images of her CT showed an absence of collateralization via the inferior mesenteric artery and Arc of Riolan.

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This could account for her postprandial abdominal pain which was midabdominal, but the midsternal chest pain was difficult to explain. A cardiac cause had been ruled out at her home institution. It was on the lower part of the sternum and bordered the epigastrium. Through my work with median arcuate ligament syndrome, it was not unusual to have chest pain be part of the pain syndrome which comes about through the compression of the celiac plexus by the median arcuate ligament (reference), and treated effectively with the division of the median arcuate ligament and celiac plexus neurolysis.

I did feel that revascularizing the SMA was likely to improve her postprandial symptoms, given the paucity of circulation to the gut. I had a discussion about her chest pain and the thought that this was a celiac plexus neuropathy as the result of compression of the celiac plexus by her Takayasu’s disease. Typically, for younger people, I perform a bifurcated graft to the celiac axis and SMA from the distal descending thoracic aorta for younger patients, but I had no intention of replacing her aorta at this time, and wanted to reserve any definitive revascularization of her visceral vessels for a later time if it became necessary. Her pulses were full in the legs and she had no hypertension, renal insufficiency, or claudication. I therefore planned a ilio-mesenteric bypass, as it would preserve planes for a later more definitive operation if necessary, and would address her mesenteric ischemia.

I also proposed taking down the median arcuate ligament and lysing her celiac plexus to treat her chest pain symptoms. While I knew this would be fraught with some hazard because of the inflammation that had been there, it would be the best chance at treating this symptom that was debilitating her. I did not think the constant chest/epigastric pain had a vascular etiology. Normally, I would test this with a celiac plexus block, but given the likely inflammation involved, a failed block would not be helpful, and a positive one achieved with some difficulty.

The patient thought this was reasonable and agreed. She underwent a midline laparotomy and I exposed both the SMA and right common iliac artery in the retroperitoneum and tunneled a PTFE graft in a C-pattern in the retroperitoneum. The SMA was diseased proximally under the pancreas and affected by inflammatory scar tissue, and the vessel was thickened as well. The iliac pulse was normal and full and provided excellent inflow.

Going into the lesser sac, the crurae of the diaphragm were heavily scarred near the celiac axis. Division of these fiber was taken slowly and with the aid of both loupe magnification and a hook cautery (borrowed from laparoscopic surgery). The aorta was cleared of tissue first -it was also encased in scar tissue. The dissection going distally was made difficult by inflammatory scar tissue as well, but several large nerve trunks were encountered and divided. The celiac axis was atretic and small within this scar tissue, but was released down to the trifurcation.

The recovery was notable for remission of her chest pain and her ability to resume eating without pain or nausea. A CTA done before discharge showed a patent bypass.

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Followup communication has revealed continued remission of her presenting symptoms months after her operation.

We are working on presenting a followup to our recent paper on MALS. Increasingly, it is apparent that consideration of celiac plexus compression as an etiology of epigastric abdominal pain unexplained by more common gastrointestinal causes provides solutions for patients given no explanation for their debilitating pain. This pain can also affect the chest, and flanks and back in the distal thoracic dermatomes, and mimic the some of the symptoms of mesenteric ischemia. In those with recurrent MALS after a successful ligament release and interval of symptom remission, even in the absence of celiac axis compression, a positive response to a celiac plexus block points to the presence of either remnant plexus fibers or compression by scar tissue of the cut nerve endings (neuromata) and reoperation has been successful. Extrapolating this experience to this patient with inflammatory compression of the celiac plexus secondary to Takayasu’s Arteritis made sense and celiac neurolysis appears effective.

Reference

Weber JM, Boules M, Fong K, Abraham B, Bena J, El-Hayek K, Kroh M, Park WM. Median arcuate ligament syndrome is not a vascular disease. Ann Vasc Surg. 2016 Jan;30:22-7.

Tissue from a MAL release (median arcuate ligament) is nerve

This was removed during a laparoscopic median arcuate ligament release. It was a hard white band compressed under the ligament and itself compressing the celiac axis. During the release, I grabbed a piece of these fibers and sent it for pathology under the preliminary diagnosis of celiac plexus, and it was. Described as “typical for a peripheral nerve…mostly Schwann cell nuclei in between nerve fiber.” Other micrographs in the specimen had ganglionic fibers but our pathologist wasn’t able to locate it. This is an important piece of the pathoanatomy because I believe that this is the nidus of the pain associated with median arcuate ligament syndrome, not a regional ischemia that can only occur if the celiac axis is an end artery, which can really only happen after a major exenteration like a Whipple procedure.

The Median Arcuate Ligament Compresses the Celiac Plexus -Pathoanatomy

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This is a picture from several years ago when I released the median arcuate ligament with open surgery. Seen tented up by the right angle clamp is the fibromuscular tissue over the celiac axis. You can also see a cord of celiac plexus, which gives the foregut somatic sensory innervation. It is becoming clearer that MALS is a nerve compression syndrome in the same way that carpal tunnel compression of the median nerve or thoracic outlet compression of the brachial plexus causes pain. Like nTOS, the arterial compression is a bystander, but a necessary finding in the diagnosis. The celiac axis and median arcuate ligament acts as a nerve compressor. This is why people with MALS respond to celiac plexus block and why it makes sense they don’t have mesenteric ischemia.

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Median Arcuate Ligament Syndrome (MALS) Is Not a Vascular Disease

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Median arcuate ligament syndrome has some disrepute among vascular surgeons because it does not make intrinsic sense that an isolated celiac axis stenosis, an intermittent one at that, would cause a regional mesenteric ischemia in a population that is in the literature, generally younger than the classic population seen for chronic mesenteric ischemia. And it shouldn’t, because no exceptions to the physiology and anatomy of mesenteric ischemia can be made.

The finding that some younger patients present with post prandial upper abdominal pain with associated compression of the celiac axis by the median arcuate ligament of the diaphragm dates to the 1960’s. These patients lose weight and find relief by leaning forward, standing, and crouching. They resort to small volume liquid diets in extreme cases, and more than 50 pounds of weight loss is seen.

During my fellowship, we treated these with operative release of the median arcuate ligament and there would be fibrosis and the celiac plexus, nerves mediating somatic pain from the foregut, would be ablated during the dissection. Inevitably, the celiac axis would undergo a patch or bypass because of the chronic scarring on the artery due to the compression. For the past two years, in collaboration with Drs. Matthew Kroh and Kevin El-Hayek (now in CCF Abu Dhabi), these releases have been performed laparoscopically, and celiac stents are hardly ever used.

John Weber, our vascular surgery chief resident, has prepared this data and we have submitted it to the PVSS for the meeting in February. Not thinking of this as a vascular disease, but rather a nerve compression disease, much like neurogenic thoracic outlet syndrome or carpel tunnel syndrome, the pathoanatomy and clinical presentation make far more sense. There is inflammation typically and nerves are ablated, and celiac plexus block, it turns out, is an excellent screening tool when the classic presentation is not present. It is analogous to using a scalene block in neurogenic thoracic outlet syndrome. Redo operation is feasible if the original procedure fails to relieve pain completely, if the celiac plexus block works to block the pain.

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Celiac Plexus under Median Arcuate Ligament

 

Link to article in Consult QD, CCF’s Clinical Blog