Spine Fusion Methods and Materials Keep Getting Better and Better
Scientists are working their way through a puzzling maze of information about bone fusions. A common place for bone fusion is in the spine. A common problem is fusion failure, when spinal movement happens where the fusion should be solid. Movement at a fusion site is called pseudoarthrosis.
Fusion has changed step-by-step as researchers find out more and more. We know that bone healing is delayed by smoking, diabetes, rheumatoid arthritis, and long-term use of some drugs. We know that using your own bone for the graft usually gives a better fusion result.
A new area of study centers on growth factor (GF) found in the platelets of the blood. GF increases bone growth. In fact, scientists found that GFs make more GFs. More GFs means more bone cells. Autologous GFs (AGFs) means your own GFs are used rather than GF from someone else.
Some studies are looking at what happens when AGFs are put right on the bone fusion. Other researchers are trying AGF with bone grafts. In this study AGF was used to enhance bone growth when fusion was done with a newer way of fusing the spine.
The newer procedure is called transforaminal lumbar interbody fusion (TLIF). TLIF with AGF is done by removing the disc from between two vertebral bones. Then bone chips taken from the patient's pelvic bone and AGF, are packed into the front third of the empty disc space. A titanium mesh cage is placed behind the bone chips. The cage is filled with pieces of bone graft. Bone graft is added around the back half of the fusion site. Screws are then placed along the back of the spine.
Spinal fusion rate was 96 percent in the patients who had TLIF with AGF. Patients who had only one level fused had 100 percent fusion success. Patients with a two-level fusion had 90 percent success. The result of TLIF with AGF was compared to a group without AGF. The bone healed faster in the AGF group, but the pseudoarthrosis rate was the same. This means that spinal fusion is faster (occurs within the first six months) but not better with AGF. The authors conclude that more studies are needed before AGF is used for every spinal fusion.
Hwan T. Hee, et al. Do Autologous Growth Factors Enhance Transforaminal Lumbar Interbody Fusion? In European Spine Journal. August 2003. Vol. 12. No. 4. Pp. 400-407.