[Radiation injury of the spinal cord]

The literature dealing with radiation myelopathy is reviewed. The following points are to be noticed:radiation myelopathy is a rare complication in the radiation therapy of extraspinal tumors, nevertheless the number of case reports is increasing during the last years; probably this is due to the increasing use of high energy therapy. Already a cord dose of 1000 rad may be dangerous; with an increasing dose the risk of radiation myelopathy is increasing too. Besides the total dose the incidence of radiation myelopathy depends on the rate of delivery, the over-all time of administration, the size of the individual fraction, the field size, the size of the volume irradiated, the type of irradiation, the use of hyperbaric oxygen and some other special conditions of radiation. But the incidence of radiation myelopathy depends not only on radiation technique but also on patients' variables. Individual variations in radiosensitivity are a well known fact; this may be partly due to an inherent biologic variation of response. Moreover the incidence of radiation myelopathy may be intensified by simultaneously existing diseases - above all by hypertension- and probably by some medicaments taken simultaneously. A dependence from age, sex, and the kind of the primary tumor seems not to exist. Radiation lesions of the cervical spinal cord have been reported much more frequently than lesions of the dorsal spinal cord; lesions of the lumbal spinal cord are a very rare event. There exist different conceptions of the pathogenesis: opinions differ as to whether the effect is primarily on the connective tissue and blood vessels or on nerve cells and their axons or if the different tissues are injured simultaneously; moreover an autoimmuno-hypothesis is discussed. The clinical signs of radiation myelopathy can be grouped into two major syndromes: the transient radiation myelopathy and the delayed or chronic radiation myelopathy, which usually develops gradually with a subsequent chronic progressive course but in some cases may occur acutely after the latent period; the course is not always progressive but may be undulating and remissions have been reported in some rare cases...