STENOSIS OF CENTRAL CANAL OF SPINAL-CORD IN MAN - INCIDENCE AND PATHOLOGICAL FINDINGS IN 232 AUTOPSY CASES

The central canal of the spinal cord is generally regarded as a vestig ial structure that is obliterated after birth in 70% to 80% of the gen eral population. This report describes the first detailed histological study of the human central canal in 232 subjects ranging in age from 6 weeks' gestation to 92 years. Whole spinal cords were harvested at a utopsy and sectioned serially from the conus medullaris to the upper m edulla. Histological findings and morphometric analysis of the cross-s ectional luminal area were used to grade stenosis at seven levels of t he canal. Varying grades of stenosis were present at one or more level s in none (0%) of 60 fetuses, one (3%) of 34 infants, three (18%) of 1 7 children, 21 (88%) of 24 adolescents and young adults, 67 (96%) of 7 0 middle-aged adults, and all 27 adults aged 65 years or older (100%). The stenotic process was most pronounced in the thoracic segments of the canal and involved more levels with higher grades of stenosis in o lder individuals. Histological findings consisted of disorganization o f the ependymal epithelium, formation of ependymal rosettes or microca nals, proliferation of subependymal gliovascular buds, and intracanali cular gliosis. These features are consistent with a pathological lesio n involving ependymal injury and scarring and are less compatible with an involutional or degenerative process. Stenosis of the central cana l probably influences the anatomical features of syringomyelia and may account for variations in cavity formation such as the prevalence of holocord syrinxes in children, the formation of focal and paracentral syrinxes in adults, and the rare incidence of syrinx formation in many older individuals with acquired lesions known to produce syringomyeli a.