Bone Graft Substitutes for Lumbar Spine Fusion Surgery

Bone graft for spine fusion

There is a lot of interest in the spine community to develop a bone graft substitute to use during lumbar spinal fusion surgery procedures. Bone graft substitutes would eliminate the need to harvest the patient’s own bone, thus potentially reducing the risk and pain associated with the procedure and hopefully leading to a more reliable result (e.g. higher fusion rates).

Spinal fusion surgery entails stopping the motion at a painful motion segment (the joint formed by two vertebral bodies). The theory is that if the joint does not move, it will not create pain. The fusion itself is achieved placing bone along or in between the vertebral bodies. As the bone grows, it fuses the vertebrae together and eliminates the motion at that segment of the spine.

Issues with current bone graft procedures for spine fusion

The gold standard for bone graft used for lumbar spine fusion has been bone harvested from the patient’s pelvis, which is a surgical procedure performed at the time of the spine fusion surgery.

There are two main potential problems with harvesting bone from the patient’s pelvis:

• Graft site morbidity
  Taking the bone graft from the patient’s pelvis is a surgical procedure. With proper surgical techniques, bone graft site morbidity can be decreased (see surgical techniques under bone grafts). There is, however, always the potential for a complication. Some of these potential complications include bleeding, infection, and chronic pain at the donor site in the pelvis. Some statistics suggest that up to 20% of patients may continue to report ongoing pain from their bone donor site.

• Failure to fuse (pseudoarthrosis or nonunion)
  Even if the spine fusion operation is performed correctly, not every patient will obtain a solid fusion. Spinal instrumentation has to some extent reduced the risk of not getting a solid fusion, but there are some patients who are still at high risk for a pseudoarthrosis (e.g. patients who have had multiple spine surgeries, who are obese, who smoke, or who are having a multilevel spine fusion).

The above two issues, graft site morbidity and failure to fuse, are the two primary reasons there has been a great deal of interest in creating a bone graft substitute for use in a spine fusion procedure instead of using the patient’s own bone.