Effects Of Postoperative Irradiation Research Articles

Effects of Irradiation on Nerve Graft Vasculature

Increasing doses of therapeutic irradiation are known to impair nerve regeneration after grafting. One possible factor is the effect of irradiation on the endoneurial vasculature. This study investigates the effects of postoperative irradiation on the size, number, and cross-sectional area of endoneurial vessels in the rat posterior tibial nerve graft model. Sixty-five Sprague-Dawley rats underwent 1.5-cm interposition grafts to the tibial nerve. Postoperatively, they were assigned to one of five groups. The animals in Group 1 were unirradiated controls. Groups 2 to 5 received postoperative irradiation in the amounts of 46, 66, 86, and 106 Gy, respectively. One hundred and twenty days after grafting, sections of the proximal, grafted, and distal nerve were harvested and analyzed with digital morphometry. Statistical analysis of the average vessel area, number of vessels, and total vascular area was performed. The grafted segments of Groups 4 and 5 and the distal segments of all irradiated groups showed a statistically significant decrease in the number of vessels, compared to controls. The average size of the vessel was smaller in the proximal segment of the irradiated groups, compared to controls. There was no difference in size in either the grafted or distal segments of the irradiated groups, compared to controls. The observed changes in the endoneurial vasculature resulted from both the action of regeneration and the effects of irradiation. The irradiation effects appear to be dose-dependent.

Long-term cardiac side effects of post operative irradiation studied with myocardial scintigraphy

Long-term cardiac side effects of post operative irradiation studied with myocardial scintigraphy

Periphneral nerve regeneration: The effects of postoperative irradiation: Evans GRD, Brandt K, Ang K, et al. Plast Reconstr Surg 100:375, 1997

Periphneral nerve regeneration: The effects of postoperative irradiation: Evans GRD, Brandt K, Ang K, et al. Plast Reconstr Surg 100:375, 1997

Peripheral nerve regeneration: the effects of postoperative irradiation.

The purpose of this study was to evaluate the effects of postoperative external cobalt-60 beam irradiation on nerve regeneration. Sixty-five 250-gm male Sprague-Dawley rats were studied. Peripheral nerve regeneration was measured by walking track analysis and histomorphology of the proximal, graft, and distal nerve segments. These 65 animals underwent a 1.5-cm interpositional nerve graft into the right posterior tibial nerve. The left leg served as a control. Each animal was then randomly allocated into one of four groups. Group 1 served as control. Groups 2 through 4 were subjected to external cobalt-60 gamma-ray irradiation through a 2.5-cm circular portal for a total fractionated dose of 30, 50, and 70 Gy beginning on postoperative day 3. Radiation was administered in 2-Gy fractions, 5 fractions per week, with a top-up dose of 16 Gy given at the end of the fractionated irradiation. Walking track analysis was performed at 30, 60, 90, and 120 days after nerve grafting. At the conclusion of 120 days, sections of the proximal, grafted, and distal nerve were harvested, stained, and examined histomorphologically. Hematoxylin and eosin stains also were obtained. Evaluation of the print-length index demonstrated no statistical difference between the unirradiated controls and the irradiated groups. The total number of axons per square millimeter and nerve fiber density per square millimeter were significantly decreased in the distal segment of all the irradiated groups when compared with controls. Despite the reduction in myelinated regenerating fibers, no reduction in function was observed, as measured by walking track analysis. We would therefore recommend immediate reconstruction of peripheral nerve defects in the face of postoperative irradiation.

2134 The effects of postoperative irradiation on loco-regional tumor control and survival in patients with head and neck carcinomas by tumor subsites and relative risk factors for recurrence

2134 The effects of postoperative irradiation on loco-regional tumor control and survival in patients with head and neck carcinomas by tumor subsites and relative risk factors for recurrence