Spondylolysis Deformans

A type of degenerative disease of the spine whose most obvious pathologic and radiographic finding is the presence of osteophytes, especially along the anterior and lateral aspects of the vertebral column. Any segment of the vertebral column may be affected. In the thoracic region the osteophytes predominate on the right side, probably because the pulsations of the descending aorta on the left side inhibit bone production.

Spondylosis deformans is believed to be initiated by abnormalities in the peripheral fibres of the anulus fibrosus. Anterior and anterolateral discal displacement may then occur and may lead to traction at the site of bone attachment of the outermost fibres of the anulus fibrosus or short perivertebral ligaments to the vertebral surfaces. At this location osteophytes develop several mm from the discovertebral junction.

Spinal osteophytes accompanying spondylosis deformans can be distinguished from the bony outgrowths of the vertebral column occurring in other pathologic conditions, such as intervertebral osteo chondrosis, diffuse idiopathic skeletal hyperostosis DISH , ankylosing spondylitis, psoriatic arthritis, Reiters syndrome, neuropathic osteoarthropathy, ochronosis, fluorosis, hypoparathyroidism and sternocostoclavicular hyperostosis.