When is back pain a fracture?

Compression fractures of the spine
Spinal fractures that occur as a result of osteoporosis are actually quite common, occurring in approximately 750,000 people in the U.S. each year. The problem is that the fracture is not always diagnosed—instead, the problem is often just thought of as general back pain, such as from a muscle strain or other soft tissue injury, or as a common part of aging. Because of this, approximately two thirds—or 500,000—of the vertebral fractures that occur each year are not diagnosed and therefore not treated.

Spinal fractures due to osteoporosis often occur while doing something that causes relatively minor trauma to the spine, such as opening a window, an insignificant fall, or twisting while lifting. Advanced cases of osteoporosis can even lead to a vertebral fracture with routine activities that would normally not cause any trauma, such as sneezing, coughing or turning over in bed.

Vertebral fractures are usually followed by acute back pain, and may lead to chronic pain, deformity (thoracic kyphosis, commonly referred to as a dowager's hump), loss of height, crowding of internal organs, and loss of muscle and aerobic conditioning due to lack of activities and exercise. A combination of the above problems from vertebral fractures can also lead to changes in the individual’s self-image, which in turn can adversely affect self esteem and ability to carry on the activities of daily living.

It’s important to note that fractures from osteoporosis don’t just occur in the elderly, they can also occur in people as young as 40 or 50 years old. Because osteoporosis is a “silent” disease, meaning that there are typically no symptoms until a fracture occurs, it is not uncommon for someone with back pain to be unaware of the fact that she has actually fractured a vertebra (or multiple vertebrae) in her spine.

This article provides an overview of vertebral compression fractures caused by osteoporosis, including symptoms and diagnosis.

Osteoporosis is the main cause of vertebral fractures
Osteoporosis is fairly common disease, and is especially common in postmenopausal women. In fact, it is estimated that approximately 25 percent of all postmenopausal women in the United States have had a vertebral compression fracture.¹ Osteoporosis also occurs in men, but is far more prevalent in women—approximately four times as many women have low bone mass, or osteoporosis, as men.

Osteoporosis causes bones to thin and become more brittle and weak. When the bones in the spine weaken they can break or cave in under normal pressure. The thinning bones can collapse during normal activity, leading to a spinal fracture. These compression fractures can cause a great deal of pain and can permanently alter the shape and strength of the spine.

The type of break in the spine that is typically caused by osteoporosis is called a compression fracture, usually defined as a vertebral bone in the spine that has decreased at least 15 to 20% in height due to fracture (as seen on an x-ray). These compression fractures can occur in vertebrae anywhere in the spine, but they tend to occur most commonly in the upper back (thoracic spine), particularly in the lower vertebrae of that section of the spine (e.g. T10, T11, T12). They rarely occur above the T7 level of the spine.

With a compression fracture caused by osteoporosis, the fracture usually occurs in the front of the vertebra, collapsing the bone in the front of the spine and leaving the back of the same bone unchanged. This results in a wedge shaped vertebra. Because the majority of damage is limited to the front of the vertebral column, the fracture is usually stable and rarely associated with any nerve or spinal cord damage.

Unlike many other conditions that can be treated before a serious complication develops, usually a fracture is the first sign that someone has osteoporosis. By the time a fracture occurs, the osteoporosis is usually advanced and the individual is then susceptible to more vertebral fractures.

Reference:

Melton LJ 3d. Epidemiology of spinal osteoporosis. Spine. 1997;22:2S-11S.