Morphology Analysis To The Injury Of Rabbit Sciatic Nerve After Stereotactic Radiation.

BACKGROUND AND OBJECT:Peripheral nerve is a well differentiated tissue, and belongs to the late effective tissues. Previously, peripheral nerve was considered as radioresistant tissue. However, as the survival time prolonged due to the modern technique, radio-induced peripheral nerve injury became more and more important. Several authors reported the incidence rates of radio-induced cranial nerve injury in nasopharyngeal carcinoma patients treated with radiation therapy is 5%-20%. Risk of radio-induced Brachial plexus neuropathy injury is rise following survival time prolong, the percentage of patients with plexopathy was 3.9% after 5 years, 24. 5% after 10 years, 27.9% after 15 years, and 54.0% after 19 years, respectively. Intraoperative radiotherapy (IORT) delivered a single high fractionated dose to the tumor bed in a purpose to enhance local tumor control. Peripheral nerve remains a dose-limiting normal tissue since it was always not possible to be moved outside of the irradiated field. IORT is mainly applied to abdominal and pelvic tumor. In those cases, lumbosacral root inevitably received more doses.Previous studies by using of IORT showed radiation caused damage to the microvasculature and peripheral parenchyma of the nerve which resulted in hypoxia, followed by nerve fiber loss and demyelination, the ultimate result is block of nerve conduction. However, IORT technique was applied in all of these studies after dissecting of the experiment peripheral nerve. In those cases, a large volume of peripheral tissue including the blood vessel would receive high doses of irradiation.