The lower part of the human spine consists of the lumbar vertebrae (usually five), the triangular shaped sacrum and the coccyx. Degeneration of the bone takes place in these areas in a sense, but as Nathan Wei, M.D. points out, the degeneration that primarily occurs involves the joints between the bones. Osteoporosis and Paget's disease are the two main conditions which affect the vertebral bodies, whereas spondylosis, ankylosing spondylitis, diffuse idiopathic skeletal hyperostosis and Reiter's syndrome are the main conditions degenerating the joints of the lower spine.
Osteoporosis
Osteoporosis is a common bone degeneration disease characterized by decreased bone density, especially in thin, elderly Caucasian women. General aging, lack of exercise and nutritional deficiencies are the most common causes. The entire lower spine can be affected and compression fractures can result with progression. According to the National Osteoporosis Foundation, 10 million Americans are estimated to have osteoporosis, 80 percent of which are women.
Paget's Disease
Paget's might also be considered a degenerative bone disease as it results in fragile bones, especially in the elderly. It's a progressive disorder of bone recycling, in which normal bone is removed and replaced with abnormal bone. Paget's is estimated to occur in 2 to 3 percent of persons older than 60 in the United States. The risk is increased about sevenfold in close relatives of patients with Paget's, although its cause is unknown. In the lower spine, the fourth lumbar segment is often affected and becomes larger and sclerotic.
Spondylosis
Spondylosis is a progressive degenerative arthritis of the vertebral bodies and discs of the spine. It affects the entire spine and is considered common among both sexes beyond the age of 45. It frequently occurs in the fourth and fifth lumbar segments because of the increased weight bearing in that region. Trauma and poor posture are additional causes. Early signs include wearing down of the discs and formation of bone spurs. Stiffness is common initially, but as it progresses over many years, compression of nerve roots (leading to sciatica) or of the spinal cord may result.
Ankylosis Spondylitis
Ankylosing spondylitis is a chronic inflammatory disorder of the spine and axial skeleton affecting mainly younger adult males. It creates bone spurs and causes degeneration in the entire lumbar spine and sacroiliac joints, which connect the sacrum to the pelvis. Chronic low back pain and increasing stiffness are common clinical signs. As it progresses, spinal fusion can occur, which is sometimes called "bamboo spine." Its cause remains unknown.
Diffuse Idiopathic Skeletal Hyperostosis (DISH)
DISH is a spinal and joint disorder characterized by calcification and ossification (turning to bone) of the ligaments which surround the vertebral bodies of the spine. An incidence of 12 percent of middle-aged and elderly Americans is estimated. In the lower spine, the first and secondnd lumbar segments are the areas affected. Stiffness, loss of normal lumbar curvature, and a "dripping candle wax" appearance on X-ray are the most common clinical features.
Reiter's Syndrome
Reiter's is defined as a triad of complications stemming from venereal disease and sexual exposure, primarily infection of the urethra, conjunctivitis, and joint inflammation and degeneration. The sacroiliac area is most commonly affected, but the upper lumbar regions are susceptible. Swelling, tenderness, and eventually erosion of the bone occurs.
References
- Arthritis Treatments: Dr. Nathan Wei, M.D.
- "Essentials of Skeletal Radiology;" Terry R. Yochum, D.C.; 2004
- National Osteoporosis Foundation
