Aortoiliac arteriovenous fistula simulating iliac vein thrombosis following intervertebral disc surgery.

This report describes an unusual presentation of arteriovenous fistula secondary to intervertebral disc surgery. A 61-year-old obese woman underwent operation for a herniated intervertebral disc. One month later she was readmitted with painful swelling of the left calf. The condition progressed to include pigmentation of the whole extremity with varicosities and ulcerations. The femoral vein was found to be occluded and there were multiple collateral vessels in the thigh. Initially, phlebitis was diagnosed, then iliac vein thrombosis. Her symptoms improved slightly with rest and anticoagulant therapy. Finally, after 2 years, an arteriovenous fistula was suspected because of a bruit in the presacral region and oxygen saturation of venous blood in the thigh. The diagnosis was confirmed by aortography. The fistula was transected and the artery and vein individually sutured, producing immediate improvement. The patient was symptom-free 3 years later. When chronic venous obstruction, unusual distribution of collateral circulation and pigmentation of a lower extremity are found after disc surgery, an arteriovenous fistula should be suspected. The diagnostic procedures should include auscultation of the abdomen and back, venography, measurement of blood oxygen levels in the collateral venous circulation and aortography.