Persistent sciatic artery: embryology, pathology, and treatment.

PURPOSE

The purpose of this article is to describe the embryologic development and anomalous persistence of the sciatic artery, pathologic changes that may occur in the persistent sciatic artery, and management of complications related to these pathologic changes.

METHODS

Two patients with persistence of the sciatic artery treated in the authors' experience are reported. In addition, the computerized data base of the University of Mississippi Medical Center was searched for patients with other lower extremity arterial aneurysms, and their records were reviewed for possible aneurysm of a persistent sciatic artery. A review of the literature was undertaken to determine the embryologic development of the persistent sciatic artery, the pathologic changes that have been observed in the sciatic artery, clinical findings associated with these pathologic changes, and methods of treatment.

RESULTS

Two patients with persistence of the sciatic artery were treated by the authors. No other cases were identified in 43 patients with 66 lower extremity aneurysms treated at our institution. The first patient presented with acute lower extremity ischemia caused by thrombosis of a sciatic artery aneurysm and was treated successfully with intraarterial thrombolytic therapy followed by interposition graft repair. In the second case an incidental unilateral persistent sciatic artery was identified in a patient with bilateral Buerger's disease presenting with digital gangrene of the contralateral extremity in whom below-knee amputation was eventually required. Bilateral tibial artery occlusion was observed on arteriography. Histologic examination of the amputated limb confirmed findings typical of Buerger's disease, and no microemboli were seen.

DISCUSSION

The sciatic artery is a continuation of the internal iliac artery and is the primary blood supply to the lower limb bud during early fetal development. The sciatic artery normally involutes during fetal development, but remnants persist as the popliteal and peroneal arteries after the superficial femoral artery develops and establishes continuity with the popliteal artery. Persistence of the sciatic artery as the major blood supply to the lower extremity in adults is a rare vascular anomaly that may be of surgical significance. Failure to appreciate the persistent sciatic artery as the major inflow into the lower extremity may lead to inappropriate bypass of apparent occlusive disease of the superficial femoral artery. The persistent sciatic artery is also frequently aneurysmal, which may cause critical limb ischemia resulting from thrombosis or embolization of aneurysm thrombus. Options for vascular reconstruction include interposition graft replacement and standard femoropopliteal bypass grafting if the common femoral artery is sufficiently developed to provide adequate inflow. As with other peripheral arterial aneurysms resulting in thrombosis and extensive distal arterial embolization and thrombosis, intraarterial thrombolytic therapy may be useful in selected cases before definitive surgical revascularization.