H. Yamada et al., MORPHOLOGICAL-STUDY OF EXPERIMENTAL SYRINGOMYELIA WITH KAOLIN-INDUCEDHYDROCEPHALUS IN A CANINE MODEL, Journal of neurosurgery, 84(6), 1996, pp. 999-1005
In this morphological study the authors investigated whether spinal co
rd cavitation, produced in young mongrel dogs that had been rendered h
ydrocephalic by cisternal injection of kaolin, consists of a dilated c
entral canal or intramedullary cavities. Hydrocephalus was noted in 50
of 56 dogs treated with kaolin. Of the 50 hydrocephalic young dogs, 2
9 were shown to have central canal dilation that was prominent at the
thoracic level and 21 to have cervical intramedullary cavities in the
posterior column and/or the posterior hem. In 11 dogs from the latter
group these cavities were demonstrated to have no communication with t
he central canal. This finding could not be explained by the hydrodyna
mic theory. On histopathological examination, myelomalacia and hemorrh
agic infarction following ventricular shunting were noted adjacent to
the cervical cavities, which suggested vascular impairment. A perfusio
n study revealed insufficient blood flow within the cervical cord at t
he level of the intramedullary cavities. A close correlation between t
he vascular insufficiency of the cervical cord and the pressure cone r
esulting from significant hydrocephalus was observed. The latter may c
ause cervicomedullary compression at the foramen magnum, affecting the
venous drainage of the cervical cord below that level, resulting in i
ntramedullary cavitation. Accordingly, vascular impairment was thought
to play a significant role in the development of cervical syrinx form
ation in our kaolin model. The current results may provide a reasonabl
e explanation for the formation of noncommunicating cervical syringomy
elia in Chiari I malformation.