|Year : 2015 | Volume
| Issue : 4 | Page : 154-155
Persistent Asymptomatic Left-sided Sciatic Artery: A Rare Case Report with Review of Literature
Amit Mahajan, Anil Luther, Premjith Chandran
Department of Vascular Surgery, Christian Medical College, Ludhiana, Punjab, India
|Date of Web Publication||13-Apr-2016|
Department of Vascular Surgery, Christian Medical College, Ludhiana, Punjab
Source of Support: None, Conflict of Interest: None
Persistent sciatic artery is a very uncommon embryologic vascular anomaly, with a prevalence of 0.05% based on reported studies. Although the majority of these patients are asymptomatic, it continues to be one of the risk factors for vascular compromise to lower extremity due to the rare complications associated with it such as aneurysmal dilatation, thrombosis or embolic phenomena, and arteriovenous malformations. We present a rare case of a 45-year-old woman with severe narrowing of bilateral superficial femoral arteries, and the left inferior gluteal artery continuing as the popliteal artery.
Keywords: Inferior gluteal artery, persistent, popliteal artery, sciatic artery
|How to cite this article:|
Mahajan A, Luther A, Chandran P. Persistent Asymptomatic Left-sided Sciatic Artery: A Rare Case Report with Review of Literature. Indian J Vasc Endovasc Surg 2015;2:154-5
|How to cite this URL:|
Mahajan A, Luther A, Chandran P. Persistent Asymptomatic Left-sided Sciatic Artery: A Rare Case Report with Review of Literature. Indian J Vasc Endovasc Surg [serial online] 2015 [cited 2020 Jan 24];2:154-5. Available from: http://www.indjvascsurg.org/text.asp?2015/2/4/154/180123
| Introduction|| |
The sciatic artery is the main blood supply to the lower extremity in the human embryo prior to the development of the femoral artery. The persistent sciatic artery or arteria comitans nervi ischiadici is a rare vascular variant. It is a branch of the internal iliac artery. It leaves the pelvis in proximity with the sciatic nerve and it continues as the popliteal artery. It was first reported by Green in The Lancet in1832.  The lack of regression of embryonic axial artery leads to this anomaly. Sciatic artery is a continuation of the internal iliac artery, which communicates with popliteal artery and tibial arteries distally. Once the femoral artery starts developing, the sciatic artery starts involuting, a process which is completed by the 3 rd week of gestation, leaving behind the inferior gluteal artery. Until date <100 cases of persistent sciatic artery had been reported worldwide. We report a rare case of a woman with severe narrowing of bilateral superficial femoral arteries, and the left inferior gluteal artery continuing as the popliteal artery.
| Case Report|| |
A 45-year-old woman with no comorbidities sought for medical care at our hospital with complaints of pain right lower limb for 5 years. She describes it as a claudication type of pain with no rest pain. On physical examination, bilateral anterior tibial artery pulsations were feeble, and pulsations over dorsalis pedis were not palpable. Doppler study of bilateral lower limbs showed reduced and biphasic flow in bilateral anterior tibial arteries and dorsalis pedis arteries.
Computed tomography (CT) angiography [Figure 1] showed narrowing of bilateral superficial femoral arteries with left inferior gluteal artery coursing along the posterior aspect of the thigh and is continuing as popliteal artery in the popliteal fossa. Bilateral anterior tibial arteries are narrow in calibre, and bilateral dorsalis pedis arteries are not visualized. Since the patient was asymptomatic on the left side, medical line of treatment was offered to the patient with close follow-up.
| Discussion|| |
Persistent sciatic artery also named as an artery to sciatic nerve, accompany artery to ischiadic nerve, ischio-popliteal artery, or persistent axis artery is a rare embryologic anomaly reported in 0.025-0.04% of people.  In 50% cases, it occurs on the right and in 20% in the left and bilaterally in 30%. It affects both genders equally and can present clinically at any age. The average age of presentation is 44 years.
The sciatic artery is a branch of umbilical artery, and it is the principal arterial supply of lower limb during 6 mm stage of embryologic development. The upper portion of sciatic artery atrophies and is replaced by the femoral artery, which develops from external iliac artery by the 3 rd month. The internal iliac artery develops from the umbilical artery. The inferior gluteal artery, the distal popliteal artery, and peroneal artery are the only remnants of sciatic artery present at birth. The persistent sciatic artery may be complete or incomplete. In complete type, sciatic artery is a continuation of the large internal iliac artery and is accompanied by sciatic nerve and continues as popliteal artery. A sciatic artery that is discontinuous between pelvis and the popliteal fossa is called the incomplete type.
Pillet et al. classifies persistent sciatic artery  as:
- Type I: Complete axial artery and normal femoral artery
- Type II: Complete axial artery and incomplete femoral artery
- (IIa) A superficial femoral artery which does not, however, reach the popliteal artery
- (IIb) No superficial femoral artery
- Type III: Incomplete axial artery. Only the upper half of artery can be found, with a normal femoral network
- Type IV: Incomplete axial artery in which only the lower half can be found with the coexistence of a normal femoral network
- Type V: Sciatic artery branching from the medial sacral artery with an existing superficial femoral artery.
The clinical diagnosis of a persistent sciatic artery can be (1) An incidental finding during arteriography (2) the presence of a pulsatile gluteal mass (3) neurological symptoms resulting from sciatic compression by a dilated aneurysm (4) unusual clinical finding of absent femoral pulse with palpable popliteal or pedal pulse, Cowies sign, due to occlusion of both external iliac and femoral artery with a patent sciatic artery.  The development of an aneurysm at the level of greater trochanter in the gluteal region is the most common complication. The etiopathogenesis is not well-understood. It can be due to mechanical (traumatic) and intrinsic causes.  Sciatic nerve compression, thrombosis or embolic phenomena with limb ischemia limb hypertrophy/atrophy, varicosities of the leg, and arteriovenous malformations are the other known complications. 
Ultrasonography Doppler, CT angiography, or magnetic resonance (MR) angiography are the useful tools which aide in the diagnosis. A Doppler study is a noninvasive technique to confirm the presence of a persistent sciatic artery and its complications.  CT angiography is superior to Doppler because it helps in the assessment of whole peripheral circulation to correctly classify the disease and evaluate for possible complications. Advantage of MR angiography is that in addition to CT angiography findings it can provide a relation between sciatic nerve and artery. The treatment of persistent sciatic artery varies according to the symptoms of the patient and type of the disease. It can vary from a simple wait and watch to vascular surgical procedures to minor/major amputations. An asymptomatic patient requires only close monitoring to prevent the risk of thromboembolic complications to avoid future amputations, in symptomatic cases with an arterial aneurysm or thrombus an endovascular procedure or surgical treatment is required. Successful surgical correction of the symptomatic patients involves excluding the anomalous artery from the circulation while revascularizing the lower extremity. 
In our case, where the woman was asymptomatic on the left lower limb where the sciatic branch of the inferior gluteal artery was continuing as popliteal artery, so no active vascular surgery was done and was managed medically.
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Conflicts of interest
There are no conflicts of interest.
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