Stenosis of the spinal canal in achondroplasia.

Stenosis of the spinal canal is a very frequent finding in achondroplastic patients. It is secondary to abnormalities of endochondrial ossification, which is responsible for formation of the vertebral bone structures, and, subsequently, to bone degeneration. Cervical stenosis (most frequently involving the first metameres and the craniospinal junction) is more common in children while thoraco-lumbar stenosis favors adults. The surgical indications for cervical stenosis depend mainly on the clinical evolution but also on neurophysiological data. In thoraco lumbar stenosis too, clinical data determine the surgical indications and the route of attack depends on the type of anatomical alteration affecting the spine.