Spinal fusion is used to hold two or more vertebrae together and prevent motion at that level of the spine. When the fusion doesn’t take and too much movement occurs, the condition is called pseudoarthrosis, which means “false joint.”
Some people aren’t able to have a fusion. For example, patients who smoke or who have diabetes are less likely to heal and form a solid fusion. Fusion may not be a good treatment choice for these patients.
Doctors are looking for ways to improve bone fusion. Electrical stimulation of the bone may be the answer. It’s been used with fractures of long bones and has only recently been tried in spinal fusions. This report summarizes the results of many studies using electrical stimulation with spinal fusion.
There are three ways to deliver an electric current to bones. Electrodes can be placed inside the body, as is done when the spine is fused. Implanted electrodes bring direct current to the bones. Two other methods can be used outside the body. One device has to be worn with a brace for eight to 10 hours each day. How well it works depends on the patient’s using it daily for six to eight months. Another external method is computer controlled and worn 24 hours a day until bone fusion occurs, which can take up to nine months.
Researchers aren’t sure how electrical signals cause bone cells to grow. They think that the electrical current sets up chemical and biologic responses that foster bone growth. More calcium appears in the cells after electrical stimulation. The authors reported the results of all three types of stimulation.
The authors conclude that many studies show promising results using electrical stimulation to improve spinal fusion. However, there are problems with the studies, and so far no one has scientifically compared all three types of stimulation. Electrical stimulation is used on a case-by-case basis and isn’t for everyone.