Osteoporosis

Bones gradually become thin as they lose their calcium and mineral structure.  This process occurs with age and becomes more progressive in the presence of disuse and immobility.  The process of bone demineralization speeds up after menopause and after long-term oral steroid use. Bone density of the spine begins to decrease by age 30.  After this time, individuals are prone to lose a small amount of bone density each year.  Approximately one-half of women over 65 years of age have X-ray evidence of thinning bone and approximately 90 percent are affected by age 75.  The altered contour of bone due to failure under weight-bearing stresses leads to changes in posture and a shift in the center of gravity.  Osteoporosis is one of the primary causes of an acquired hunched-over posture in elderly individuals, particularly women. 

The bony structure of the spine changes size and shape over time due.  This process is referred to as bone modeling.  Like other tissues of the spine, the bone repairs itself in response to the stresses placed upon it. Osteophyte development (bone spurs) occurs more often along the outer border (periphery) of the vertebral body giving the characteristic appearance on X-rays.

The internal supportive elements of bone are referred to as trabeculae. They serve in function similar to steel Beams (I-beams) in a building structure.  The loss of trabecular support is sometimes referred to as “trabecular failureâ€? or microfractures.â€?  The loss of trabecular support within the body of a vertebrae renders the vertebrae more susceptible to failure under normal and abnormal weight-bearing loads. This process reduces the load bearing capacity of bone and can result in a compression fracture.  Cracks within the bone of the vertebral body grow gradually in size until critical conditions occur, at which point a sudden spontaneous fracture may occur.  In elderly individuals vertebral collapse can occur during normal activities, such as arising stairs, getting up from a sitting position or simply stepping off of a curb.

During the aging process, progressive bone loss is inevitable although the degree of bone loss can be reduced with regular weight-bearing exercise.  Development of scoliosis in elderly women is an indicator that osteoporosis and compression fractures may be developing. Osteoporosis is one of the most common causes of spinal deformity in adults.  It tends to occur after intervertebral disc degenerative change is evident.  It is one of the most common causes of back pain in elderly individuals.