Radiation myelopathy.

Radiation myelitis has long been recognised as a sinister consequence of spinal irradiation and has limited the acceptable dose of therapeutic radiation to the cord. Over the past 10 years, the pathogenesis has been increasingly understood through the use of animal models. The importance of 'dose per fraction' and 'inter-fraction interval' have been incorporated into new mathematical models which suggest that, for small fractions, the cord may tolerate higher doses of radiation than was previously thought. Clinical recognition of the condition has improved through the description of characteristic magnetic resonance imaging changes. However little advance has been made in its treatment.