James Randolph Urbaniak

My current research interests involve two areas:

A. Blood No Reflow in Skeletal Muscle after Replantation
For the past fifteen years, we have utilized direct videomicroscopy of the microcirculation of the rat cremaster muscle supplemented by animal models of replantation, vascular crushing, and muscle function following injury and recovery in an effort to understand the mechanism of the no reflow phenomenon in microvascular reconstruction. Experimentally induced prolonged ischemia in an animal model has enabled us to document the dynamic changes and histopathology of small arteries, including vasospasm, venous dilation, and vessel wall failure. With reperfusion after prolonged ischemia, disturbances in the microcirculation include vasospasm, vortex formation, regional stasis, interstitial edema and hemorrhage, and white blood cell and platelet aggregation. The deleterious effects of systemic acidosis, interstitial hemorrhage, denervation, and prolonged venous occlusion have been documented. A major effort must be directed toward preventing the no reflow phenomenon, as we have yet to find a reliable means to reverse it. Most of our fifteen years study of the no reflow phenomenon has focused on direct, highly magnified visualization of the muscle microcirculation under a variety of conditions. The application of the information gained from these laboratory experiments has resulted in continued improvement of our success rate in clinical microvascular surgery, especially in traumatic replantation of amputated limbs.

B. The second major area of interest is in the treatment of avascular necrosis of the femoral head. We have created an animal model of avascular necrosis of the femoral head and have demonstrated that vascularized fibular bone grafting is superior to core decompression or nonvascularized bone.

For the past seventeen years, we have been following over 1,000 patients who have been treated with vascularized fibular graft to the femoral head. On long term follow-up studies, that is greater than five years, has demonstrated success of the procedure in more than 75 per cent of the patients. Outcome studies have demonstrated greater than 85 per cent patient satisfaction.