Platelet-rich plasma (PRP) (also known as blood injection therapy) is a medical treatment being used for a wide range of musculoskeletal problems. Platelet-rich plasma refers to a sample of serum (blood) plasma that has as much as four times more than the normal amount of platelets and growth factors. This treatment enhances the body’s natural ability to heal itself and is used to improve healing and shorten recovery time from acute and chronic soft tissue injuries.
Blood injection therapy of this type has been used for knee osteoarthritis, degenerative cartilage, spinal fusion, bone fractures that don’t heal, and poor wound healing. This treatment technique is fairly new in the treatment of musculoskeletal problems, but gaining popularity.
However, the use of PRP to aid spinal instability by fusing the vertebrae is still under investigation. The goal to create a bony bridge between two vertebrae has had mixed results. Most of the time, the results (measured based on how much bone growth and blood supply are stimulated) are incomplete.
Although they find some new bone growth, complete bridging of bone to form a solid fusion doesn’t occur. Signs of inflammation and some blood vessel formation are observed but not enough to consider this a successful approach to spinal instability.
Previous studies have used other materials such as stem cells, bone morphogenetic protein (BMP), and bone graft to stimulate bone bridging and fusion. But none of the studies so far have shown complete bony bridging needed for spinal fusion (including efforts to use platelet activation and release of growth factors via platelet-rich plasma injection.
Researchers have made some suggestions that might explain why PRP is not completely successful in promoting bone growth or blood supply. For example, no one really knows the ideal amount of platelets (and therefore growth factors) to use. And growth factors don’t last long before they become inactive.
Injecting them into the area is one challenge but they must also be released and activated. It is still unknown just what is the best way to deliver and activate them. Should they be “preactivated” or will they start up on their own once they reach the intended destination? Is there a way to create a “time-release” effect? These are just some of the questions that remain to be answered before platelet-rich plasma can be used routinely to enhance spinal fusion.