The human spinal column is a series of 33 individual bones or vertebra stacked on top of one another. This unique structure is charged with the important task of providing structural support for the torso, head, and neck. Osteoporosis (and some types of cancer) can cause one or more of these bones to degenerate — the spinal bone then collapses under the body’s weight. A vertebral compression fracture, as it is called, can be incredibly painful and lead to pronounced changes in posture, height, and mobility. Fortunately there are two procedures, vertebroplasty and kyphoplasty, that can rapidly repair a vertebral compression fracture and restore function and quality of life.
In both vertebroplasty and kyphoplasty, a needle is advanced into the diseased vertebra, usually under fluoroscopic guidance. A fluoroscope is a real time X-ray system that allows the physician to visualize the vertebral column and needle without opening the spine surgically. Vertebroplasty and kyphoplasty involve the injection of an acrylic cement, methylmethacrylate, into the center of the collapsed vertebra. This substance stabilizes the fracture and fuses the bone fragments together. The polymethylmethacrylate cement has some disadvantages (it rises in temperature inside the body when it hardens, which can occasionally causes problems and doesn't mesh with the body tissue as well as some newer materials). (More on synthetic bone materials.)
These procedures are found great success in relieving pain and allowing the patient to have more mobility. They also helped prevent further complications from kyphosis. Vertebroplasty, sometimes referred to as percutaneous vertebroplasty, was introduced in the 1980s. It can result in increased compressive and bending stiffness in the spine.
Kyphoplasty, the newer procedure and one considered superior to vertebroplasty for severely compressed vertebra, employs one or more balloons to restore the original height of the vertebra. In an action similar to a car jack, a kyphoplasty balloon is inserted into the center of the compressed disk and inflated, thereby providing separation between the upper and lower borders of the vertebra and raising the spinal column overall. Once the balloon restores height to the vertebra, the kyphoplasty balloon is withdrawn and the space is filled with the acrylic cement.
Both vertebroplasty and kyphoplasty are performed under local anesthesia and are not strictly surgical procedures. They are often performed either by interventional radiologists or orthopedic surgeons. Vertebroplasty can be performed on an outpatient basis though most kyphoplasty procedures require an inpatient hospital stay of at least one day. Ideal candidates for vertebroplasty and kyphoplasty are patients that have pain localized to a vertebral compression fracture that is less than 12 months old.
Approximately 85-90% of patients enjoy almost immediate relief of their fracture pain after either vertebroplasty or kyphoplasty. The procedures are very satisfying from a physician’s perspective because patients that had been suffering from months of intractable back pain leave the hospital or office pain-free in just a few hours. In both procedures, mobility is greatly improved and in kyphoplasty, a partial restoration of overall spinal column height is achieved.
Complications, which occur in fewer than ten percent of patients include local pain, a narrowing of the space in which the spinal cord rests, acrylic cement entering the nearby blood vessels, and compression of some of the nerves as they leave the spinal region. Less than one percent of patients get non-cancerous bone lesions. Doctors follow up with patients after the procedures to check for problems.
Sometimes revision procedures are required, if an infection occurs or kyphosis continues.
While these procedures can correct fractures, they cannot prevent future compression fractures in other vertebra. Neither vertebroplasty nor kyphoplasty is considered a replacement for aggressive medical treatment of the medical cause of the vertebral compression fracture. Medical treatment may include osteoporosis medications or chemotherapeutics for multiple myeloma.
Synthetic and biosynthetic
materials now available to orthopedic and spinal surgeons include collagen,
ceramics, cements, and polymers. These materials can serve as a structure
on which new bone can grow. Over time some or all of the starter materials
may dissolve, leaving only new bone behind. The benefits of these synthetic
graft materials include sterility, availability and lower morbidity