Radiologic studies of cerebrospinal fluid pathways in experimental hydrocephalus-hydrosyringomyelia.

The progress of experimental hydrocephalus-hydromyelia in cats is analyzed in the present study. The animals were rendered hydrocephalic by intracisternal injections of kaolin or by operatively occluding the lateral apertures. Changes in the cerebrospinal fluid (CSF) spaces were monitored by ventriculography or computed tomography. The progress of hydrocephalus in both groups can be divided into two stages: 1) A phase of raised intracranial pressure precedes the dilatation of the central canal, and 2) a progressive phase follows the dilatation of the central canal. The canal acts as a kind of natural bypass between the ventricles and the subarachnoid spaces. Although the spontaneous shunt, the central canal, becomes dilated and pressures drop to near normal values, the disease is apparently not brought to a complete halt. Our observations suggest that the disturbance in CSF flow dynamics is an important factor causing hydrocephalus to remain progressive.