When conservative treatments fail to relieve symptoms, doctors may refer a patient for surgery. In decompression surgery (also known as a laminectomy), doctors relieve pressure on the spinal nerves by opening up the narrowed area of the spinal canal. The procedure involves removing small areas of bone or protruding material from a herniated intervertebral disk. In some cases, patients may also require fusion to stabilize the affected area of the spine. A small amount of bone is taken from elsewhere in the body (often the hip) and placed into the space between the vertebrae. Rods and screws may be inserted into the bones to hold the vertebrae in place. Once the site heals, the upper and lower vertebrae in the affected space are permanently fused into one unit to stabilize the spine (i.e., prevent the vertebrae from slipping out of position and pressing on the spinal nerves).
According to the American Academy of Orthopaedic Surgeons, more than 325,000 spinal fusions were done in 2003. About 162,000 were on the lower spine. While the treatment is usually very successful, it has a limitation. Since the affected vertebrae are fused into one unit, the patient loses mobility in that area of the spine.
Researchers are now testing new devices for patients with spinal stenosis, called the Total Facet Arthroplasty System® (TFAS®) (made by Archus® Orthopedics). TFAS replaces the facet joints in the spine (the tiny joints between the vertebrae that enable the spine to bend). Patients still have decompression surgery. But instead of fusion, the TFAS is inserted between the vertebrae. The system stabilizes the spine and enables patients to maintain near-normal bending motion.
Barton Sachs, M.D., an Orthopedic Surgeon with Texas Back Institute, says recovery time after TFAS is quick. Patients are able to get back to normal activity in about half the time of a spinal fusion because they don't need to wait for a fusion to heal. Currently, TFAS is in clinical trials and is not yet approved for general use.
To be considered for the trial, patients must have moderate to severe spinal stenosis at a single level in a section of the lower spine. Participants will be divided into two groups. All will receive decompression surgery. Then, one-third will have standard fusion and two-thirds will receive the TFAS. Patients with osteoporosis or metabolic bone disease are not eligible for the trial. See the company's website for the most up-to-date information: http://www.facetjointreplacement.com.