Persistent Sciatic Artery with Monoplegia in Right Lower Leg Without Vascular Complication Symptoms in an Obese Woman

A rare case of a persistent sciatic artery (PSA) in a patient with monoplegia of the right lower leg without vascular complication symptoms is presented. A 44-year-old nervous and obese woman was referred with monoplegia of the right lower extremity. She was referred with an impression of a peripheral neuropathy due to nerve compression by a large uterine cyst. This impression was derived from a computed tomography (CT) scan that had been performed at the referring hospital the day before. On admission to our hospital, we repeated the CT scan and also obtained angiography that demonstrated that the problem was due to a persistent sciatic artery (PSA). The cyst was proved not to compress any vessels or nerves. The PSA was an aneurysmal dilatation from the internal iliac artery to the popliteal artery. It intermittently compressed the sciatic nerve. A persistent sciatic artery was noted to be the dominant blood supply to the right lower extremity. A right ilio-popliteal artery bypass using a 6-mm ringed ePTFE graft was performed. After arterial reconstruction, she recovered completely.