Popliteal Aneursym

Pathophysiology

1) pathologic focal enlargement of the popliteal artery in the popliteal fossa 2) prone to thrombosis and distal ischemia 3) rupture is rare 4) underlying cause is atherosclerotic disease

Signs and Symptoms

1) pulsatile mass in popliteal fossa 2) prominent pulse in distal medial thigh 3) arterial ischemia in affected leg, ranging from mild claudication to gangrene (secondary to local thrombosis or embolism to tibial or pedal arteries 4) compression of popliteal vein with limb swelling 5) compression of tibial or common peroneal nerve with pain or motor-sensory deficits

Characteristic Test Findings

Radiology – color flow duplex scanning is the diagnostic test of choice

Histology/Gross Pathology

1) true aneurysm, affecting all layers of vessel 2) significant mural thombus

Associated Conditions

1) commonly bilateral 2) 50% of popliteal aneurysms accompanied by aortic aneurysm 3) associated wtih iliac artery aneurysm

Inheritance/Epidemiology

1) most common in elderly men 2) most common peripheral aneurysm 3) bilateral in 50% of cases

Treatment

1) bypass of aneurysm with saphenous vein graft 2) surgical ligation proximal to aneurysm (even if asymptomatic) to prevent distal embolus 3) intra-arterial thrombolytic agents if acute thrombosis or embolism 4) if large aneurysm or compressive symptoms are present, the aneurysm sac is opened and thrombus is removed with ligation of all geniculate artery branches feeding the sac 5) percutaneously placed endoluminal stents are effective

Tips for USMLE

1) most common peripheral (nonaortic) aneurysm 2) often confused with a Baker’s cyst