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a 61-year - old man , with no previous history of trauma , was referred to ewha womans university mokdong hospital for further evaluation of left claudication which was appeared a month prior to admission . on physical examination ,
absence of pulsation at left dorsalis pedis was noted with relatively intact pulsation at left popliteal artery and left femoral artery .
1 ) , performed to evaluate the whole vascular bed of lower extremity , revealed the presence of complete persistent sciatic artery ( psa ) with incompletely developed superficial femoral artery ( sfa ) ( type 2a persistent sciatic artery ) , and the complete obstruction of distal popliteal artery by thrombus was also noted . despite of the complete obstruction of the distal portion , patency from internal iliac artery to proximal portion of popliteal artery through the psa
the patient was placed in prone position and a vertical incision was made over the popliteal fossa .
exposure of the popliteal artery was followed by arteriotomy and distal embolectomy using a fogarty catheter .
although mild calcification of arterial wall was found , another bypass surgery was not considered because of the relatively good arterial bed .
patient made uneventful recovery and postoperative follow - up ct angiogram showed no residual thrombus in popliteal artery ( fig .
the finding in ct angiogram was similar to the preoperative one without any interval aggravation of arteriosclerosis or aneurysmal change ( fig .
the postoperative recovery was uneventful and discharged without any complications . during the 6-year follow - up period
, he was supposed to take aspirin and warfarin for 3 years and aspirin only after that .
the sciatic artery , a branch of umbilical artery , is the main arterial supply of the developing lower limb during 6 mm stage of embryonic development . with the development of femoral artery from the external iliac artery , the sciatic artery regresses with time [ 1 - 5 ] .
the psa originated from the failure of sciatic arterial involution process , with low incidence of between 0.025% and 0.04% [ 1,3 - 5 ] .
the anomaly of this process determines the types of psa from the incomplete type to complete type with relative hypoplastic femoral artery .
pillet et al .   has suggested four different types of psa according to the result of angiogram . for the complete type ( type 1 and 2 ) psa , which has continuation with popliteal artery , the presence of normal femoral artery determines the psa type .
different from type 1 psa with normal femoral artery , type 2 represents a complete psa with relatively under - developed femoral artery .
type 2 can be subtyped again into type 2a ( presence of incomplete sfa ) and type 2b ( absence of sfa ) , according to the presence of sfa . for incomplete psa , which has partial remnant of psa and normal sfa ,
the anatomical location of spa determines the type : type 3 psa with only upper remnant of psa and type 4 with lower remnant .
the psa , which is more prone to arteriosclerosis and vessel wall degeneration , can present with combined vascular complication : aneurysmal change with or without thromboembolism . in spite of low incidence rate ,
46.1% to 47% of psa patients present combined aneurismal change with or without thromboembolism . except for asymptomatic patients ( 40% ) ,
common manifestations can be summarized as pulsatile , painful buttock mass and lower limb ischemia .
different from other peripheral obstructive disease , intact popliteal and distal pulsations with relatively weak or absent femoral pulsation can suggest psa .
the tentative diagnosis can be achieved by ct angiogram of lower extremity , which allows demonstration of the various anatomic configurations both in the sciatic and femoral arterial systems .
the choice of treatment is mainly dependent on the presence of symptoms , classification of psa ( anatomy of the sciatic artery and the iliofemoral system ) , the presence of concurrent vascular complication ( vascular occlusive disease or aneurysm ) .
asymptomatic patients with incidental findings of psa require close follow - up observation only rather than surgical intervention .
symptomatic patients are surgical candidates , and the type of surgery can be specified according to the presence of complication and classification of psa .
incomplete psa with aneurismal change , with or without vascular occlusive disease , can be obliterated by exclusion , endovascular embolization , or resection .
complete psa with aneurismal change requires concurrent revascularization procedure to prevent aggravation of lower extremity ischemia .
non - aneurismal psa with symptomatic thromboembolism can be managed with embolectomy , either by endovascular intervention or open surgical approach .
our patient showed type 2a psa ( complete psa with incompletely developed sfa system ) with distal popliteal thromboembolism .
although there would be persistent and repetitive risk of thromboembolism and aneurysmal change , we decided to perform thromboembolectomy only .
it 's because of relatively good psa without arteriosclerosis and aneurysm . by eliminating complicated operative procedures for exclusion of psa and bypass ,
treatment of symptomatic psa should be tailored to its anatomy and presentations and thromboembolectomy without bypass surgery should be considered as one of strategies in the treatment of symptomatic psa .
a persistent sciatic artery ( psa ) is very rare congenital vascular anomaly which is present in 0.025% to 0.04% of the population by an angiographic study . 
 a psa is usually combined with aneurismal disease or thromboembolic events because of its arteriosclerosis and vessel wall degeneration . 
 the treatments of symptomatic psa are comprised of exclusion of psa from circulation and bypass surgery for the lower limb . 
 however , surgical treatment should be tailored to its anatomy and presentation . 
 we report a successful treatment of psa with distal thromboembolism by thromboembolectomy without bypass surgery .