- An iatrogenic, and thus
preventable, condition in which radiation therapy for neck, thorax, and brain
tumours injures adjacent neural tissue
- Clinical sequelae:
- typically delayed
- either a transient
myelopathy developing 3-6 months post-treatment, or, more commonly, a
delayed, progressive myelopathy that develops after a latent period of
more than 6 months
- onset is insidious,
without pain; sensory symptoms (parasthesias/dysesthesias of feet and/or
hand, depending on lesion location) precede motor weakness
- slow, irregular progression
towards corticospinal and spinothalamic signs
- Pathological features
of irradiation near the spinal cord include a focal, delayed coagulation necrosis
of the cord affecting white matter more than grey with secondary degeneration
of tracts and vascular abnormalities
- Lesions are typicaly
larger than intraspinal tumours, and hence must be accurately diagnosed to
prevent unnecessary, further irradiation