Exclusion o f a sciatic artery an obturator bypass

aneurysm and

Hiroshi Urayama, MD, Masaya T a m u r a , M D , H i ro sh i Ohtake , M D , and Yoh Watanabe , M D , Kanazawa, Japan

This case report describes surgical treatment in a sciatic artery aneurysm with hypoplastic external iliac and femoral arteries. An obturator bypass grafting procedure from the internal iliac artery to the distal sciatic artery was performed after aneurysmal exclusion was achieved by proximal and distal ligation. This method offers an acceptable option for surgery in some types of sciatic artery aneurysms. (J Vase Surg 1997;26:697-9.)

Sciatic artery aneurysm is a rare disease, but it may cause significant complications, such as rupture, thrombosis, distal embolism, and sciatic neuralgia. 1-a The treatments are variable due to the inconstant anatomy and different complications involved, a Previ- ously reported methods of surgical t reatment are proximal ligation only, excision with interpositional grafting, and proximal and distal ligation with femo- ropopliteal bypass grafting. 4-6 We used a new method of aneurysmal exclusion and an obturator bypass procedure for sciatic artery aneurysm with hypoplastic external iliac and femoral arteries.

CASE R E P O R T

A 64-year-old woman consulted our department with sudden onset of pain, numbness, and coldness in her left leg. Under a diagnosis of thromboembolism in the left leg artery, heparin (8000 units/day) and uroldnase (240,000 units/day) were administered intravenously for 7 days. The patient's ankle pressure index of the left leg increased from 0 to 0.27. An angiogram and a computed tomogram revealed a persistent sciatic artery aneurysm and occlusion of the popliteal artery in the left leg (Fig. 1). Because the complaints were relieved, the patient refused surgical treat- ment. She received antiplatelet drug therapy and left the hospital.

Three months later, however, the patient returned, again with buttock pain, and she then underwent surgery. Incisions were made at the lower median abdomen and at the anteromedial midthigh (Fig. 2). The left internal iliac artery and proximal sciatic artery were exposed intraperito-

From the First Department of Surgery, Kanazawa University School of Medicine.

Reprint requests: Hiroshi Urayama, MD, First Department of Surgery, Kanazawa University School of Medicine, 13-1, Takara-machi, Kanazawa 920, Japan.

Copyright © 1997 by The Society for Vascular Surgery and Inter- national Society for Cardiovascular Surgery, North American Chapter.

0741-5214/97/$,5.00 + 0 24/4/83500

neally, and the distal sciatic artery was exposed, dividing the adductor magnus. Exclusion of the aneurysm was ac- complished with proximal and distal ligation of the sciatic artery aneurysm. Because the hypoplastic external iliac ar- tery and common femoral artery were not suitable for inflow to the distal artery, we performed a bypass grafting procedure from the internal iliac artery to the distal sciatic artery. The course of the bypass graft was through the obturator foramen, and a polytetrafluoroethylene tube with rings was used as the bypass graft. Thromboembolec- tomy of the popliteal artery was also performed with the use of balloon catheters.

A postoperative angiogram and a computed tomogram showed thromboexclusion of the sciatic aneurysm and good patency of the bypass graft and popliteal artery (Fig. 3). Leg ischemia and buttock pain disappeared after the operation, and the ankle pressure index increased to 0.94. The patient is doing well 7 months later.

D I S C U S S I O N

Embryologically, the sciatic artery is derived from the umbilical artery and runs along the dorsal aspect o f the lower limb. 7 The femoral artery develops from the external iliac artery, and connects to the popliteal artery. As the femoral artery enlarges, the sciatic artery regresses. The anomaly of this process deter- mines the types of persistent sciatic artery from the incomplete type to dominant sciatic artery with ab- sent femoral artery. The incidence o f aneurysmal formation in a persistent sciatic artery has been esti- mated as 44%, and the cause has been suggested that chronic trauma such as compression and stretching causes aneurysmal formation and that there is con- genital hypoplasia of the connective tissue of the anomalous artery. 3,6

Sciatic artery aneurysm can be suggested clinically by buttock pain with or without a pulsatile mass. 2,3 Claudication or leg ischemia may also be presenting complaints. Duplex scanning aids in detection. Com-

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JOURNAL OF VASCULAR SURGERY 698 Urayama et al. October 1997

Fig. 1. Three-dimensional computed tomogram with enhancement demonstrates sciatic ar- tery aneurysm before operation (arrow). Posterior view.

puted tomography and angiography confirm the di- agnosis, demonstrating the various anatomic config- urations in the sciatic and femoral arterial systems.

For surgical treatment o f sciatic artery aneurysms, proximal ligation causes ischemia of the leg; there- fore, some form of bypass procedure should be per- formed, s Excision with interpositional grafting car- ries the risk o f sciatic nerve injury at dissection, and graft occlusion may occur when the patient is seat- ed. 2 Recently, proximal and distal ligation of the aneurysm with simultaneous femoropopliteal bypass grafting is preferred.5 However, the patency rate of a femoropopliteal bypass graft is lower than that of an iliofemoral bypass graft, and the hypoplastic femoral artery is sometimes inadequate for bypass inflow. 9,1° An obturator bypass, which we used in this patient, is generally performed when a bypass graft can not be placed at the groin because of infection, cancer inva- sion, or radiation necrosis, n The course through the obturator foramen is the shortest among the bypass routes from the internal iliac artery to the distal sciatic artery, and using this route decreases the inci- dence of graft compression and ldnking when the patient moves.

Fig. 2. Diagram illustrates surgical procedures. External iliac and femoral arteries were hypoplastic. Sciatic artery aneurysm (dashed line) was excluded, and obturator bypass was performed from internal iliac artery to distal sciatic artery.

JOURNAL OF VASCULAR SURGERY Volume 26, Number 4 Urayama et al. 699

Fig. 3. Three-dimensional computed tomogram with enhancement demonstrates obturator bypass after operation (arrow). Posterior view.

W e c o n s i d e r aneu rysma l exc lus ion w i t h an o b t u -

r a to r bypass avai lable as an a l te rna t ive surgical t rea t -

m e n t for pa t i en t s w i t h sciatic ar tery a n e u r y s m , espe-

cially w h e n associated wi th hypoplasia o f the proximal

f e m o r a l ar tery.

R E F E R E N C E S

1. Pignoli P, Inzaghi A, Marconato R, Longo T. Acute ischemia of the lower limb in a case of persistence of the primitive sciatic artery. J Cardiovasc Snrg (Torino) 1980;21:493-7.

2. McLeilan GL, Morettin LB. Persistent sciatic artery: clinical, surgical, and angiographic aspects. Arch Surg 1982;117:817- 22.

3. Williams LR, Flanigan DP, O'Connor RJA, Schuler JJ. Persis- tent sciatic artery: clinical aspect and operative management. Am J Surg 1983;145:687-93.

4. Hutchinson JE, Cordice JWV, McAllister FF. The surgical management of an aneurysm of a primitive persistent sciatic artery. Ann Surg 1968;167:277-81.

5. Martin KW, Hyde GL, McCready RA, Hull DA. Sciatic artery aneurysms: report of three cases and review of the literature. J Vasc Surg 1986;4:365-71.

6. Branrley SK, Rigdon EE, Raju S. Persistent sciatic artery: embuology , pathology, and treatment. J Vasc Surg 1993;18: 242-8.

7. Greebe J. Congenital anomalies of the iliofemoral artery. J Cardiovasc Surg (Torino) 1977;18:317-23.

8. Mayshak DT, Flye MW. Treatment of the persistent sciatic artery. Ann Surg 1984;199:69-74.

9. Johnston ICW, Kalman PG, Baird RJ. Aortoiliofemoral occlu- sive disease. In: Veith FJ, Hobson RW, Williams RA, Wilson SE, editors. Vascular surgery. 2nd ed. New York: McGraw- Hill, 1994:409-20.

10. Veith FJ, Panetta TF, Wengerter KR, Marin ML, Rivers SP, Suggs WD, et al. Femoro-popliteal-tibial occlusive disease. In: Veith FJ, Hobson RW, Williams RA, Wilson SE, editors. Vascular surgery. 2nd ed. New York: McGraw-Hill, 1994: 421-46.

i1. Guida PM, Moore SW. Obturator bypass technique. Surg Gynecol Obstet 1969;128:1307-16.

Submitted Feb. i9, 1997; accepted May 7, i997.