Developmental disorders

II./4.3.: Natural history

Occult dysraphisms can stay completely asymptomatic, or added to a usual degenerative spine disease it may cause localized pain. Progressive lower extremity paresis, sensory deficit, or signs of damaged cauda fibers or the lower part of the spinal cord, arise the suspicion of tethered cord (tethered spinal cord) syndrome. This is a variant of the developmental disorder, in which a part of the lower end of the spinal cord is anchored to the spinal canal by a specific type of connective tissue called filum terminale. In healthy individuals the growth of the spinal cord does not follow the growth of the spinal canal, resulting in that the level of the conus moves gradually higher and higher in the canal during intrauterine growth and after birth. In healthy adults the conus is located at the altitude of the first lumbar vertebra, while with tethered cord it can stay as low as LV or SI. However, if the tethered spinal cord keeps being stretched inside the spinal canal its function will be severely damaged, causing slowly progressing neurological symptoms.