You've probably heard that the arch is one of the strongest shapes in nature. Architects have known this for millennia. That's why arches are used in the construction of bridges, great vaulted cathedrals, and massive public buildings. Your spine is composed of a series of arches that give it strength—just like the Roman Coliseum, which has stood for nearly 2,000 years. But just as any building can fall, any bone can break. The vertebrae are no exception.
What is a vertebral fracture?
A typical vertebra is composed of a body, which is roughly the shape of a heart or a kidney, attached to a bony vertebral arch. Viewed from the top, it looks something like a crown. The vertebral arch and the back of the vertebral body together form a strong, protective ring around the spinal cord.
A vertebral fracture is a broken vertebra. Vertebral fractures fall into two broad categories: traumatic (associated with injury) and pathologic (associated with disease or degeneration).
If enough force is applied, the bony arch of a vertebra can snap like a stick, particularly if you’re injured in a fall, a motor vehicle crash, or some other accident in which the vertebrae are subjected to sudden, forceful flexion (bending forward), extension (bending backward) or rotation (bending sideways). This kind of injury is called a traumatic fracture. Traumatic fractures can also develop over time if the vertebrae are subjected to sustained or repeated mechanical stress, such as running. In this discussion, we’ll focus on pathologic fractures.
Pathologic fractures usually affect the vertebral body, rather than the vertebral arch. This kind of fracture is less dramatic than a traumatic fracture because it usually doesn’t threaten the spinal cord (although it can) and because it develops slowly. Picture a crack running through an old teacup, with smaller cracks spreading out from the main fissure.
Human bone, though, is strong and porous—more like coral than china. Cracks running through a vertebra make the bone crumble, rather than snap. As it does, the compromised portion collapses, losing height and becoming compressed. This is called a compression fracture. Loss of vertebral height is, in fact, the chief criterion by which compression fractures are diagnosed. Most pathologic fractures—those associated with osteoporosis, for example—are compression fractures.
If the vertebral body cracks all over, the loss of height will be relatively even. If the lateral (side) portion is fractured, the vertebra will collapse on the fractured side. And if a fracture occurs in the front (anterior) portion of the vertebral body, the loss of height will be in the front. An anterior fracture creates a wedge-shaped vertebra. If similar fractures occur at adjacent levels, a hunched or stooped posture will result.
How common is vertebral fracture?
Vertebral fractures are extremely common among older adults. One study places the incidence at one in six women and one in 12 men; however, most people dismiss their symptoms as being nothing more than normal aches and pains. A fracture causes only mild pain in many of those who have one. As a result, less than one-third of fractures are diagnosed when they happen.
Among older adults with osteoporosis, 700,000 vertebral fractures occur every year. After age 50, a white woman in the United States has a 40% chance of vertebral fracture during her lifetime. The risk for white men is lower than that of white women. The risk among black and Asian people in the United States is lower than the risk among white women and men. Researchers estimate that 50 years from now, the worldwide incidence of osteoporosis-related vertebral fractures among all groups will be four times the current incidence.
What causes vertebral fracture?
A cascade of events contributes to vertebral fracture. The sequence usually includes immobility and associated loss of muscle and bone mass, arthritis, degenerative disc disease, and altered body mechanics that redistribute the work of supporting your body weight and facilitating movement.
Over time, these changes produce an exaggerated curvature in the thoracic spine. This abnormal front-to-back curvature is called kyphosis (from kyphos, a Greek word meaning “bent”). Kyphosis can provoke pain, compromise respiratory function, and increase the risk of falling. Fractures often occur, however, during normal activities as the bones of the spine become weak and brittle.
Certain diseases, such as rheumatoid arthritis, Parkinson’s disease, and primary aldosteronism (an adrenal gland disorder that causes high blood pressure) are associated with a higher risk of vertebral fracture. Women are at higher risk simply because they’re much more likely to have osteoporosis. Other disorders that have been linked to a higher risk of vertebral fracture include advanced age; a history of falls or fractures; alcohol or tobacco use; dementia or depression; a deficiency of estrogen, vitamin D, or calcium; and low body mass index (BMI), particularly in women. Use of thiazide diuretics for hypertension (high blood pressure) or loop diuretics for hypertension or heart failure is a risk factor as well.
What are the symptoms of vertebral fracture?
Bone tissue contains no nerve endings. Nevertheless, a vertebral fracture can be painful because the collapsed vertebra compresses surrounding structures that do have pain receptors. For example, a vertebral fracture can compromise the spinal canal, crowding the spinal cord and causing spinal stenosis and a kind of pain called myelopathy. Or the crumbling bone can compress a spinal nerve, causing a kind of nerve pain called radiculopathy. A vertebral fracture can also reduce range of motion and limit your ability to perform your daily activities. In many people, though, vertebral fracture produces no symptoms or only low-level pain.
How is vertebral fracture diagnosed?
So how do you know if you even have a fracture? Diagnosing vertebral compression fracture is surprisingly difficult. Since diagnosis is based on a loss of vertebral height, adult degenerative scoliosis (ADS) and other spinal diseases that affect vertebral height are often misdiagnosed as fractures.
Magnetic resonance imaging (MRI) is more sensitive than either radiographs (x-rays) or computed tomography (CT) studies in detecting fractured vertebrae. Because MRI is expensive, however, most fractures are diagnosed with a simple x-ray.
Fractures are usually graded as follows:
- Mild (1) = 20–25% vertebral height reduction
- Moderate (2) = More than 25% but less than 40% reduction
- Severe (3) = Greater than a 40% reduction in vertebral height
Your doctor will also ask about your general medical history, including your medications and any past surgeries. The physician will want to know when your pain began, what it feels like (sharp, dull, burning, etc.), what (if anything) brought it on, whether it’s constant or intermittent, and which activities (such as walking) make it hurt more or less. A thorough physical examination will help your doctor spot any neurologic deficits (loss of strength, sensation, or functioning) that might be attributable to a fracture.
How is vertebral fracture treated?
For most spine disorders, physicians like to let several weeks elapse before pursuing definitive treatment or diagnostic testing, since most back pain resolves on its own. But new evidence suggests that this watch-and-wait approach may not be the best course of action in patients with vertebral fractures.
More aggressive treatment might be appropriate as soon as a diagnosis of vertebral fracture is confirmed. Conservative management—physical therapy and pain management, for example—might still be useful instead of or in addition to surgery in some patients. Be sure to discuss all the options with your doctor, and ask questions about anything that’s not clear.
Physical therapy is often used in the management of spinal conditions. The goal of therapy is usually to strengthen the musculature surrounding the spine, thereby strategically redistributing some of the spine’s workload.
In patients with fractures, however, that’s not the only endpoint. Other aims of therapy are to improve your gait (walking pattern) and body mechanics. A physical therapist can even teach you how to perform preoperative exercises that make it easier for you to tolerate surgery under conscious sedation (local anesthesia), thereby eliminating the risks associated with general anesthesia.
For pain relief, your doctor can recommend over-the-counter pain relievers or prescribe effective nonopioid medications such as nonsteroidal anti-inflammatory drugs (NSAIDs). In addition, certain antidepressant agents are useful for pain management even in patients without depression. Opioid (narcotic) pain relievers may be prescribed if necessary, depending on your diagnosis and medical history.
If your fracture is osteoporosis related, your doctor may also recommend one or more of the following to maintain bone mass, build bone mineral density, prevent future fractures, and/or relieve pain:
- Vitamin D
- Bisphosphonates such as Fosamax
- Hormone replacement therapy (HRT) (in women)
- Synthetic calcitonin, a naturally occurring hormone produced by the human thyroid gland
- Teriparatide, a recombinant form of parathyroid hormone (PTH)
Little reliable scientific research is available on the effectiveness of using a brace to treat vertebral fracture. In addition, if a brace is used, it’s not clear whether a rigid brace or a soft one is more effective. Some limited evidence indicates that use of a hard brace might reduce pain by immobilizing the spine and supporting trunk muscles. But no brace can help if the patient doesn’t wear it, and compliance — that is, the patient’s willingness to comply with doctor’s orders to wear the brace — can be lacking.
Two surgical procedures have been used to treat vertebral fracture: vertebroplasty and kyphoplasty.
Vertebroplasty is a procedure in which a cement-like substance is injected into the vertebral body in order to stabilize the spine and relieve pain. Recent evidence, however, suggests that this procedure is no more effective than a sham procedure. A sham procedure is the surgical equivalent of a placebo pill. In this case, study participants all underwent a surgical procedure. Some of them were injected with the vertebral cement, and others were simply anesthetized, opened up, and stitched right back up again. Neither group knew whether they’d received the treatment. Since research has been unable to demonstrate the benefit of vertebroplasty, the American Association of Orthopedic Surgeons no longer recommends it.
The other surgical procedure used to treat vertebral fracture is called kyphoplasty. This procedure is a lot like vertebroplasty, but with one key difference: instead of simply injecting cement into the collapsed disc space, the surgeon first uses a balloon or coil to create a chamber, of sorts. This chamber is then filled in order to restore disc height. Sometimes bone cement is used, and in other procedures the newly opened disc space is filled with a small implant.
This procedure can be performed using a keyhole technique called percutaneous kyphoplasty (PKP). (Percutaneous simply means “through the skin.”) This procedure reduces time under anesthesia, minimizes blood loss, lowers the risk of infection, shortens recovery time, and makes recovery much easier and less painful. A wealth of evidence, including a high rate of patient satisfaction, shows that kyphoplasty is effective in relieving pain and reducing the risk of subsequent vertebral fracture even in patients with a compromised spinal canal.