In 2002, the US Food and Drug Administration (FDA) approved the InFUSE Bone Graft/LT-CAGE lumbar tapered fusion device. This device is used in the lower region of the spine as a treatment for degenerative disc disease. Its arrival has been welcome news for many older Americans. By the age of 50, approximately 85% of adults show some evidence of disc degeneration.
Degenerative disc disease (DDD), a significant cause of back pain in adults, is a disorder of the spine that can be quite debilitating. The spine is formed from 26 bones or vertebrae that are separated by intervertebral discs. These discs, which are cushion-like pads, act as shock absorbers during activity. In DDD, the discs become damaged, and may lead to back and leg pain. Spinal fusion surgery is sometimes used to treat DDD. Most people with DDD are never operated upon. Yet, more than 190,000 Americans are expected to have spinal fusion surgeries in 2002.
What Happens in Spinal Fusion Surgery
In spinal fusion surgery, two or more vertebrae are "welded" together to eliminate the pain caused by the damaged disc in the spine. To do this, a surgeon inserts pieces of the patient's own bone (usually harvested from the hip) between the vertebrae to prompt the body to grow new bone. This process requires two steps. The implanting the bone in the spine, and removing the small pieces of bone from the patient's hip. Some studies have shown that the bone-harvesting surgery can be more painful than the fusion surgery itself. Nearly one-third of patients experience hip pain two years following surgery. The InFUSE Bone Graft eliminates the need for this bone-harvesting surgery.
How the New Device Works
The device consists of three components split between two parts: a metallic tapered spinal fusion cage (LT-CAGE lumbar tapered fusion device) and a bone graft substitute (InFUSE Bone Graft). The InFUSE Bone Graft consists of a protein (rhBMP-2) and a carrier for the protein. These two components are placed inside the fusion cage.
rhBMP-2 is a genetically engineered version of a naturally occurring protein that is capable of initiating bone growth or bone regeneration in specific, targeted areas in the spine. The LT-CAGE stabilizes the spine, while the rhBMP-2 stimulates bone growth and the spine fuses.
What the Evidence Says
A multicenter, randomized, two-year study was conducted with 279 people with DDD. All the participants received the LT-CAGE device. Approximately half of the people received autograft bone, and the rest received InFUSE Bone Graft. The study demonstrated that the use of the LT-CAGE device with InFUSE Bone Graft was effective for promoting spinal fusion. Both groups in the study received similar levels of low back pain relief. Since the InFUSE group did not have the hip surgery, they experienced no additional hip pain and spent less time in the operating room. However, because only one study has evaluated this device, and no long term safety or efficacy data has been published, a thorough discussion with your doctor is necessary before undertaking ths procedure. While the procedure appears promising it is some time away from being considered standard medical practice.
The InFUSE Bone Graft /LT-CAGE lumbar tapered fusion device should not be used if you are pregnant or are suspected to be pregnant.
