Mönckeberg’s arteriosclerosis: vascular calcification complicating microvascular surgery

Abstract

Mönckeberg’s arteriosclerosis is often an incidental finding, identified either clinically or on plain radiography. It can occasionally be associated with diabetes mellitus or chronic kidney disease. It differs from the more common atherosclerosis in that the tunica intima remains largely unaffected and the diameter of the vessel lumen is preserved. Despite such vessels appearing hard and pulseless throughout their affected length, they deliver relatively normal distal perfusion, indeed there is often a bounding pulse at the end of the calcified zone. They appear unremarkable on magnetic resonance angiography but visibly calcified on plain radiography. Mönckeberg’s arteriosclerosis has a prevalence of < 1% of the population, but when it does occur it can cause consternation at the prospect of using these vessels for microvascular anastamosis. We report our experience of deliberately using these vessels in an osseocutaneous radial forearm free flap reconstruction. Although there are some technical considerations to bear in mind, we would suggest that unlike vessels affected by atherosclerosis, anastomosis of arteries affected by Mönckeberg’s arteriosclerosis has little or no impact on free flap survival.

Mönckeberg’s arteriosclerosis is a form of vessel hardening in small- and medium-sized arteries as a result of tunica media calcification ( Fig. 1 ). It is often an incidental finding, identified either clinically or on plain radiography, and can occasionally be associated with diabetes mellitus or chronic kidney disease. Its distinctions from atherosclerosis are the striking calcification of the tunica media of small- and medium-sized arteries, particularly in the forearms and legs, together with an absence of lumenal narrowing and intimal disruption. The venous system, lacking a thick muscular media, remains unaffected. Although clinically asymptomatic it presents strikingly as hard, pulseless calcification, often throughout the length of the affected vessel. Despite this, such vessels deliver relatively normal distal perfusion, indeed there is often a bounding pulse at the end of the calcified zone. Described clinically as ‘pipe-stem’ arteries, this is visible on plain radiographs as ‘rail-tracking’ of the vessel. They appear unremarkable on magnetic resonance angiography. This condition although relatively rare (0.6% of the population) has and will dissuade microvascular surgeons from using such vessels for free flap reconstruction. We present our experience of such a case and a review of the literature.

Fig. 1
Cross-section through a medium-sized artery, showing calcification (dark purple) in the tunica media and an intact tunica intima. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Case report

A 64-year-old man presented with a T4N0 squamous cell carcinoma of the alveolus of the left body of the mandible. He was a non-smoker and was diagnosed with atrial fibrillation in the surgical work-up. He had had previous lower spinal surgery through an anterior trans-iliac approach. His lower legs were cold and hairless, with diminution of the pedal pulses and mild pitting oedema. A surgical plan of segmental resection was planned and a magnetic resonance angiogram of his lower legs arranged. This showed bilateral stenosis of the anterior tibial vessels and taken with the clinical findings precluded a fibula free flap. In consultation with the anaesthetic team we planned for an osseocutaneous radial forearm free flap. Although the patient had a positive bilateral Allen’s test, the radial arteries were bony hard and could be palpated throughout their forearm course. Plain radiographs of the forearm confirmed ‘rail-tracking’ calcification of these vessels, consistent with a diagnosis of Mönckeberg’s arteriosclerosis ( Fig. 2 ). The anaesthetist did not feel that the radial arteries could be cannulated for the arterial line and sought an alternative site. Supported by the positive Allen’s test we opted to use the non-dominant forearm for our flap.

Jan 17, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Mönckeberg’s arteriosclerosis: vascular calcification complicating microvascular surgery
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