a persistent sciatic artery ( psa ) is a rare vascular anomaly with an estimated incidence of 0.020.04% and with a high rate of complications such as aneurysm formation , thromboembolism , and ischemia , that may lead to amputation .
we present a case of a female patient with complete symptomatic ambilateral psa and with unilateral aneurysm .
the aneurysm was excised and the ptfe graft was interposed at the aneurismal sac ( femoro - popliteal bypass could not be performed because of the high degree hypoplasia of the superficial femoral artery ) .
the graft endured continuous compression and stretching during regular daily life of the patient . at check - up 18 years after the operation , the doppler ultrasound showed a patent graft and no new aneurismal dilatation of the sciatic artery .
to our knowledge the follow - up of the presented case is the longest reported so far in the literature .
the uneventful course of the patient confirms that classical aneurysmectomy still constitutes one of the treatment options of psa aneurysm .
persistent sciatic artery ( psa ) is a rare , but potentially serious vascular anomaly . in mammals , during the early fetal period , it connects the internal iliac artery with the popliteal artery and is the major blood supply to the lower limb in embryonic development . at that time the trunk runs down along with the sciatic nerve on the dorsal surface of the hip joint and the extensor muscles of the thigh . during
further fetal development ( after 6 weeks ) , due to position changes of the pelvis , which deteriorates the blood supply , the sciatic artery undergoes gradual involution . in mammals
remains of the sciatic artery take part in the formation of the inferior gluteal artery , deep femoral artery , fibular artery and the arteries of the foot . in the literature this vascular anomaly is called  persistent sciatic artery  ,  persistent axial artery  , or
are represented by a descending branch of the inferior gluteal artery , which at the level between the sciatic tuberositas and major trochanter forms a long and very thin branch called the committing artery of the sciatic nerve , which accompanies the sciatic nerve down to the popliteal fossa . in the most common (  complete  ) form of this vascular anomaly ,
the internal iliac artery and its continuity psa leave the minor pelvis and enter the thigh through the lower portion of the greater sciatic foramen , below the pyriform muscle , running down to the posterior femoral compartment and accompanying sciatic nerve .
psa has a variable relationship to the sciatic nerve , occasionally lying within the nerve sheath . at the level of the popliteal fossa
it joins the popliteal artery . the profound femoral artery is usually preserved , whereas the superficial femoral artery in most cases ( over 70% ) is hypoplastic or even aplastic and ends in the form of several small branches at the distal part of the thigh [ 13,5,7,8,10,12,13 ] .
the persistent sciatic artery usually runs a torturous course , is fragile and prone to vasculopathy , atherosclerosis , and aneurysm formation mostly due to hypertension and chronic trauma .
the potentially serious complications of psa include ischemia due to occlusive thrombosis or thromboembolization , formation and rupture of an aneurysm .
we present a rare case of the complete symptomatic bilateral psa with hypoplastic femoral arteries and unilateral aneurysm , treated successfully , with an 18-year period of uneventful follow - up .
in 1991 a 63-year - old non - smoking female was referred to the outpatient vascular service of our clinic , with a 2-year history of pain of varying intensity , localized in the left buttock , radiating down along the left thigh with concomitant paresthesias of the left foot .
she was initially treated at a neurological unit . during the second year she experienced 2 incidents of acute pain of the left toe accompanied by the symptoms of the  blue toe  syndrome .
six months before , she began to feel discomfort , compression , and pulsatile mass in her left buttock . on admission ,
ankle / brachial index ( ab / i ) on the left was 0.67 and on the right 0.86 . on physical examination ,
the initial angiograms ( figures 1 , 2 ) revealed ambilaterally enlarged internal iliac arteries which ran down the thighs in a posterior location and joined the popliteal arteries . on the left side
the superficial femoral arteries were hypoplastic , and tapered gradually , ending as small branches at the distal thighs .
it was diagnosed as psa ( with aneurysm ) , type iia , according to pillet .
the aneurysm was directly exposed and excised ( figure 3 ) . to restore the blood flow ,
a ptfe graft # 12 ( 12 cm long ) was implanted in the place of the aneurismal sac in an end - to - end way ( figure 4 ) .
the patient was discharged on the 12 postoperative day , free of symptoms and without any neurological deficit from the sciatic nerve .
however , we managed to call her for check - up on june 2009 , when she was 82 .
she did not report any complaints that could be directly attributed to the blood supply to the lower limbs .
ab / i of her left foot was 0.76 and on the right ab / i was 0.81 .
the doppler ultrasound showed a patent graft and no new aneurismal dilatation of the sciatic arteries .
it has been estimated that in approximately 0.020.04% of adults the sciatic artery persists as the main artery supplying the lower limb [ 1,4,5,8,10,1114 ] .
one needs to be especially aware of the psa presence in the case of hip surgery , since there may be a certain overlap of symptoms , or during renal transplantation .
division of the internal iliac artery for the graft renal artery anastomosis would result in limb ischemia if there was a psa .
histological study of resected sciatic artery usually demonstrates severe atherosclerotic changes , with a deficit in the collagen components of the vessel wall .
psa is a rare condition , but this artery is especially prone to develop atherosclerotic changes , embolism and aneurismal formation . whereas major arteries normally follow a course on the flexor aspects of articulations , the psa courses posteriorly in the buttock and thigh and is subjected to repeated mechanical trauma ( eg , compression against the edge of a chair while sitting or overstretching when walking ) .
this may result in aneurysmal formation ( unilateral aneurysm is found in over 40% of cases of psa , while bilateral aneurysm in more than 12% of psa cases ) , typically under the gluteus maximus muscle at the level of the greater trochanter [ 1,4,5,912 ] .
aneurysmal complications such as rupture , thrombosis or embolism constitute a high risk of acute ischemia and are still connected with a substantial rate of limb amputations , which is why early surgical intervention is increasingly regarded as preferable in case of the symptomatic psa with aneurysm .
treatment of psa depends on the type of sciatic artery involved . in a case where the sciatic artery exists as the primary arterial supply to the extremity in the so - called  complete  form of psa ( approximately two - thirds of reported cases ) revascularization of the distal extremity
multiple surgical techniques are available , including interposition grafting or femoro - popliteal bypass grafting in combination with ligation or resection of the aneurysm .
recently , endovascular techniques such as percutaneous embolization with coils have been tried , providing symptomatic improvement , especially in cases of incomplete psa where revascularization is usually unnecessary [ 5,11,1719 ] . in cases requiring continuity of the sciatic artery ,
percutaneous endovascular management of the lesion with stent - graft represents a further treatment option [ 5,11,1719 ] .
however , whether or not endovascular procedures represent a reasonable alternative to classic surgical techniques is yet to be determined , because a stent graft in this location bears the potential risk for graft dislodgment or compression over the hip joint , and its durability remains an open question . in our case , because of poor perfusion , and the fact that the left distal superficial femoral artery was hypoplastic and did not supply adequate flow to the lower extremity , we could not limit our procedure to the exclusion of the aneurismal sac , or perform a femoro - popliteal bypass . additionally , endovascular procedures were not available to us at that time .
that is why we decided to interpose the graft at the place of the excised aneurismal sac .
we were aware that , theoretically , placing the graft in the same position as the aneurysm was not the optimal solution , because such a graft could be exposed to incidents of repeated trauma or stretching , as it had been the sciatic artery .
it could increase the risk of leaks at the anastomotic sites or cause graft thrombosis .
however , in this case the graft endured continuous compression during regular daily life of the patient over a period of years . in an extensive english language review of this subject , van hooft et al noticed that presented follow - up was short ( 612 months ) and poorly described in most articles , thus therapeutic strategies could not be deduced from the available literature .
to our knowledge the follow - up of the presented case is the longest reported so far in the literature .
 summarybackgrounda persistent sciatic artery ( psa ) is a rare vascular anomaly with an estimated incidence of 0.020.04% and with a high rate of complications such as aneurysm formation , thromboembolism , and ischemia , that may lead to amputation.case reportwe present a case of a female patient with complete symptomatic ambilateral psa and with unilateral aneurysm . 
 the aneurysm was excised and the ptfe graft was interposed at the aneurismal sac ( femoro - popliteal bypass could not be performed because of the high degree hypoplasia of the superficial femoral artery ) . 
 the graft endured continuous compression and stretching during regular daily life of the patient . at check - up 18 years after the operation , the doppler ultrasound showed a patent graft and no new aneurismal dilatation of the sciatic artery.conclusionsto our knowledge the follow - up of the presented case is the longest reported so far in the literature . 
 the uneventful course of the patient confirms that classical aneurysmectomy still constitutes one of the treatment options of psa aneurysm . 
Background
Case Report
Conclusions
Background
Case Report
Discussion
Conclusions