The spine is made up of strong bones called vertebrae. A vertebra can break, however, just like any other bone in the body. When a vertebra breaks and then collapses, it is called a vertebral compression fracture. Compression fractures happen most commonly in the thoracic spine (the middle portion of the spine). In the worst cases, such fractures and the resulting compression of the spine can put pressure on the spinal cord and nerves, either from the compression itself or from the protrusion of bone into the nerves of the spinal cord.
Vertebral fractures most often result from a very hard fall or another type of injury. Most healthy bones can withstand pressure, and the spine is able to absorb the shock of sudden force. However, if the force is too strong or the spine is too weak (most often due to osteoporosis), one or more vertebrae may fracture.
Fracturing becomes more likely when the spine bends forward at the same time that downward pressure impacts the spine. For example, falling to the floor in a sitting position simultaneously bends the spine and thrusts the head forward. This posture, combined with the traumatic impact on the buttocks, concentrates pressure on the front part of the spine, and this pressure can cause a fracture. Compression fractures due to trauma can come from a fall, a forceful jump, a car accident, or any other event that stresses the spine past its breaking point.
Osteoporosis often acts as an underlying cause of compression fractures. As osteoporosis thins bones, they can become too weak to bear normal pressure. And when a vertebra becomes too weak to withstand normal pressure, it may take very little additional pressure to cause it to collapse. Eventually, even normal activity can cause a compression fracture in a spine already weakened by osteoporosis. Bending forward, for example, can be enough to cause a "crush fracture" in a weakened vertebra. This type of fracture causes the loss of body height and a humped back (kyphosis), especially in elderly women. Forty percent of all women will have at least one spinal compression fracture by the time they turn 80 years old, making it the most common type of fracture associated with osteoporosis.
Finally, cancer that spreads to the spine may also contribute to a compression fracture. Cancer can weaken the spine's supportive structure and cause destruction of part of a vertebra, weakening the bone until it collapses.
WHERE DOES IT HURT?
A fracture caused by a sudden, forceful injury will probably produce severe pain in the back, legs, and arms. If the fracture also injures the nerves of the spine, it may result in feelings of numbness or weakness.
If the bone fractures and collapses more gradually--as a result of bone thinning, for example--the pain will usually be milder. In fact, there might be no pain at all until the bone actually breaks. In severe compression fractures, parts of the back of the vertebral body may actually protrude into the spinal canal and put pressure on the spinal cord.
Your doctor will take a history of the problem, and may recommend certain diagnostic tests. The most common diagnostic tool for this problem is an X-ray, which can quickly show where any vertebrae have been broken. If your doctor has any concerns about possible damage to the spinal cord, he or she may also suggest a CT scan and a myelogram. A neurological exam may also be given.
The most common treatments for a thoracic compression fracture are bracing, decreasing activity, and mild pain medications. Remember that medications will not help the fracture to heal, but they can help control pain. Vertebral fractures usually take about three months to heal fully. Non-surgical, minimally-invasive procedures, such as kyphoplasty, can also be used to treat compression fractures.
Surgery might be necessary to prevent the bone from collapsing onto spinal nerves and causing more serious damage. Your doctor may suggest some type of internal fixation to hold the vertebra in the proper position while it heals. In addition, the surgeon may need to remove any bone fragments that put too much pressure on the spinal cord.