When symptoms are severe or debilitating, surgery may be recommended. In a laminectomy or spinal decompression, surgeons remove bone and sections of soft tissue that are pressing on the spinal nerves. Some patients also require spinal fusion to stabilize the spine. Small amounts of bone are taken from the hip and placed into the space between the two target vertebrae. Tiny screws and rods are usually implanted to hold the vertebrae in place. Over time, the bone fragments heal into a solid segment, permanently fusing the top and bottom vertebrae as a single unit.
The American Academy of Orthopaedic Surgeons estimates 325,000 spinal fusions were performed in 2005. About 162,000 of the procedures were done on the lower (lumbar) spine. Spinal fusion is successful in about 80 percent of patients. But the treatment prevents movement, or bending, between the two fused vertebrae. If only two vertebrae are fused, patients generally won't see any significant changes in mobility. However, recent research shows, over time, fusion can put more pressure on the vertebrae immediately above and below the fused section, leading to more disk degeneration.
Researchers are now testing a new type of device for patients with moderate to severe lumbar spinal stenosis. It's called the TOPS™ System, or Total Posterior Arthroplasty Implant. The TOPS system is designed to stabilize the spine after decompression without the need for fusion. It consists of two titanium plates connected by a flexible core that's covered in a polycarbonate urethane sleeve. After decompression, the TOPS device is inserted into the space between the vertebrae. Four tiny screws hold it in place.
Stephen Robbins, M.D. is an Orthopaedic Surgeon at Columbia St. Mary's Hospital in Milwaukee. He says, after placement of TOPS, patients usually have immediate relief from symptoms. They are able to stand and walk as soon as they get out of recovery. They are out of the hospital in about two days. With traditional fusion, it takes at least three months for the bones to heal and six months to a year for complete fusion. So rehabilitation is delayed. With the TOPS system, there is no need to wait for fusion to heal. Rehabilitation can begin quickly and patients get back to normal activities very quickly. In addition, the flexible core of the TOPS system enables near normal bending and range of motion in the spine. Robbins is hopeful that will take the pressure off adjacent vertebrae and reduce the risk of future deterioration of disks in upper and lower vertebrae.
TOPS is currently in a Phase III trial at 8 sites across the U.S. For more information, log onto http://www.clinicaltrials.gov. Then type the trial identification number in the search box: NCT00405691.