[Pathogenesis of syringomyelia]

Formation of syringomyelic cavities may be caused by known pathologic processes, e.g. neoplastic tumours, arachnitis, traumas or malformations of the cranio-vertebral junction, while pathogenesis of idiopathic, primary syringomyelia has not been established so far. This paper presents a historic review of hypotheses and theories concerning the aetiology and pathophysiology of syringomyelia and their critical discussion. It points out the importance of communication between extracellular and subarachnoid spaces through the Virchov-Robin perivascular space. Disturbance of the outflow of extracellular fluid of the spinal cord may lead to dilatation of these canals and to formation of syringomyelic cavities because of raised volume of extracellular fluid.