Compression fractures in people with weakened vertebrae are usually caused either by falling or by placing a load on outstretched arms (for example, by raising a window or lifting a small child or bag of groceries). Such spinal fractures typically cause the front of the vertebrae to collapse.
Bone loss in the spine takes place rapidly around the time of menopause, and an estimated 25 percent of American women over the age of 50 experience one or more compression fractures of their vertebrae in their lifetime. Men account for approximately one seventh of the vertebral compression fractures associated with osteoporosis.
A vertebral compression fracture due to osteoporosis is accompanied by intense, localized back pain in about 80 percent of cases, although there may be no pain until a few days after the fracture. When pain does develop, it can be severe enough to incapacitate a person for several weeks. The pain worsens during activities that involve twisting or bending and initially does not ease up, even with bed rest.
Typically, the pain will resolve after several weeks with the use of mild analgesics and rest. The pain may continue and get worse, however, if the bone fails to heal because of a loss of blood supply or if the vertebral deformity that results from the fracture either accelerates degenerative changes in the facet joints or compresses a nerve root.
A frequent problem immediately following a fracture in the lower lumbar region is difficulty with urination and bowel movements. Fortunately, this is temporary.
Longer-term repercussions include stooped posture as well as loss of height. These structural changes reduce the amount of space available for vital organs such as the stomach and lungs. Compression of the stomach causes the abdomen to protrude and creates a sensation of indigestion or fullness that may lead to weight loss, while compression of the chest cavity leads to a reduction in lung capacity that can contribute to breathlessness or lung disease.
Structural changes caused by vertebral compression fractures also weaken the spinal extensor muscles, leading to fatigue. In addition, they can cause concerns about physical appearance and make it difficult to find clothes that fit properly. All of these problems may lead to depression as well as difficulty sitting or sleeping. Rarely, a severe vertebral collapse may cause paralysis by exerting pressure on the spinal cord.