Bilateral persistent sciatic arteries complicated by unilateral acute lower limb ischaemia

Abstract

We present a case of a middle-aged Caucasian woman who developed acuteon top of chronic limb ischaemia secondary to thrombotic occlusion of a persistent sciatic artery (PSA). Timely investigation and treatment were instituted resulting in a favourable outcome. PSA is an uncommon congenital, developmental, arterial anomaly which can cause serious lower limb complications such as acute or critical limb ischaemia and amputation. As this condition is rarely encountered in regular clinical practice, and has a limb-threatening potential, it is important to be aware of its cause, presentation and management. We describe the embryologic aetiology of PSA and discuss different investigation modalities and treatment options.

Arteries of the Lower Limb—Embryology, Variations, and Clinical Significance

“…The persistent sciatic artery (PSA) occurs when the embryological sciatic artery fails to regress (Figures 2 and 3). [26][27][28] This occurs when there is hypoplasia or incomplete formation of the femoral artery. The reasons for insufficient femoral artery development are not well understood, but likely based on failure of complex molecular interactions.…”

“…The reasons for insufficient femoral artery development are not well understood, but likely based on failure of complex molecular interactions. 27 The PSA occurs with an estimated incidence of 0.03-0.06%. 26 It begins as a branch of the internal iliac artery and passes through the greater sciatic foramen.…”

“…This results in vessel wall weakness by destruction of the media/adventitia and aneurysm formation. 26,27 A third theory is that congenital alterations lead to reduced elasticity in the arterial wall and lead to aneurysm formation. 29 However, aberrant molecular signaling, e.g.…”

Incidental Finding of Complete Bilateral Persistent Sciatic Arteries

“…The PSA is due to failure of regression and may be associated with hypoplasia of the femoral arterial system in some cases (7). Some authors have postulated that the sciatic artery persists in cases when the femoral arteries do not develop completely, however, the reasons for abnormal development are unknown (3). A genetic mutation or vascular event triggered by the in utero environment has been suggested as a possible cause (6).…”

“…Persistence of bilateral sciatic arteries is exceptionally rare, occurring in 12-32% of cases (1). The PSA anomaly was first described as a post-mortem finding by Green in 1832 (2) and has since been reported in fewer than 200 cases (3). The majority of cases are asymptomatic and found incidentally, particularly in young patients, but may later go on to present with symptoms of claudication and rarely, sciatica (4,5).…”