Age-Related Morphological Change of the Central Canal of the Human Spinal Cord and the Mechanism of Syrinx Formation in Syringomyelia and Hydromyelia

Summary

To elucidate the physiological and pathogenetic role of the human central spinal canal in acquired syringomyelia, we analyzed age-related morphological changes of the normal human central canal of the spinal cord and discussed the mechanism of syrinx formation in syringomyelia and hydromyelia. The subjects included 158 cases ranging in age from 1 day post gestation to 116 years. Autopsy cases of syringomyelia and hydromyelia were also examined. Microscopic images of the central canal were classified as patent or occluded at each level for each age decade. The patency rate under 1 year of age was 100% in almost all segments, which markedly decreased in the second decade, and the canals were occluded in all segments with advancing age. The occlusion of the central canal started at T6 and L5 to S2 levels. In cases of acquired syringomyelia, there was no communication between the central canal and the syrinx, in contrast to hydromyelia. From these observations, we suggest that the central canal does not function after infancy because of its occlusion and that it is not involved in the development of syringomyelia in adult patients.