Experimental communicating syringomyelia in dogs after cisternal kaolin injection. Part 1. Morphology.

Intracisternal kaolin injection in dogs usually produces hydrocephalus and out of 16 such dogs 11 have shown enlargement of the central canal of the spinal cord which has proceeded to syringomyelia-like cavities in 7 instances. The morphology of the cavities is described, the absence of ischaemic changes in the cord noted and the occasional communication of the cavities with the spinal subarachnoid space at the level of the filum terminale confirmed. The similarities to human syringomyelia are noted together with important differences in the etiology. The dogs all had arachnoiditis, all had hydrocephalus and all had a radiologically demonstrable communication of the cavities with the 4th ventricle, findings which are unusual in human syringomyelia.