An estimated 10 million Americans have osteoporosis, and an additional 34 million are estimated to have low bone mass, placing them at increased risk for developing this condition.
Of the 10 million Americans with osteoporosis, 8 million women have the condition and 2 million men. Along with hip and wrist fractures, severe osteoporosis can cause compression fractures in the spine. This occurs when the bony block or vertebral body in the spine collapses, which can lead to severe pain, deformity and loss of height. While osteoporosis is the most common cause, these fractures may also be caused by trauma or metastatic tumors. "In the past, people with severe pain from vertebral compression fractures (VCFs) were treated with bed rest, medications, bracing, or invasive spinal surgery, usually with limited effectiveness," said Christopher Shaffrey, MD, a spine surgeon and American Association of Neurological Surgeons (AANS) spokesperson.
Vertebroplasty for the treatment of VCFs was introduced in the United States in the early 1990s. The procedure is usually done on an outpatient basis, although some patients stay in the hospital overnight. Vertebroplasty takes from one to two hours to perform, depending on the number of vertebrae being treated. The procedure may be performed with a local anesthetic and intravenous sedation or general anesthesia. Using x-ray guidance, a small needle containing specially formulated acrylic bone cement is injected into the collapsed vertebra. The cement hardens within minutes, strengthening and stabilizing the fractured vertebra. Most experts believe that pain relief is achieved through mechanical support and stability provided by the bone cement.
A newer procedure, called kyphoplasty, involves an added procedure performed before the cement is injected into the vertebra. First, two small incisions are made and a probe is placed into the vertebral space where the fracture is located. The bone is drilled and one balloon (called a bone tamp) is inserted on each side. The two balloons are then inflated with contrast medium (which are visualized using image guidance x-rays) until they expand to the desired height and removed. The spaces created by the balloons are then filled with the cement. Kyphoplasty has the added benefit of restoring height to the spine.
Patients with the following criteria may be considered candidates for vertebroplasty or kyphoplasty:
•Osteoporotic VCFs in any area of the spine that have been present for more than two weeks, causing moderate to severe pain, and unresponsive to conservative therapy
•Painful metastases and multiple myelomas
•Painful vertebral hemangiomas (benign, malformed vascular tumors composed of newly formed blood vessels)
•Vertebral osteonecrosis (a condition resulting from poor blood supply to an area of bone, which causes bone death)
•Reinforcement of a pathologically weak vertebral body before a surgical stabilization procedure
Patients with any of the following criteria should not undergo these procedures:
•A VCF that is completely healed or is responding effectively to conservative therapy
•A VCF that has been present for more than one year
•Greater than 80 to 90 percent collapse of the vertebral body
•Spinal curvature such as scoliosis or kyphosis that is due to causes other than osteoporosis
•Spinal stenosis or herniated discs with nerve or spinal cord compression and loss of neurological function not associated with a VCF
•Untreated coagulopathy (a disease or condition affecting the blood's ability to coagulate)
•Osteomyelitis (an inflammation of the bone and bone marrow, usually caused by bacterial infection)
•Discitis (nonbacterial inflammation of an intervertebral disc or disc space)
•Significant compromise of the spinal canal caused by impeding bone fragment or tumor
Complication rates for vertebroplasty and kyphoplasty have been estimated at less than 2 percent for osteoporotic VCFs and up to 10 percent for malignant tumor-related VCFs. The benefits of surgery should always be weighed carefully against its risks. "Although a large percentage of patients report significant pain relief after these two procedures, there is no guarantee that surgery will help every individual," stated Dr. Shaffrey.