Spine Specialists On-Call: Biologic Materials -- Dawn of a New Era in Spine Surgery

One of the leaders in this field is Jeffrey C. Wang, M.D. Dr. Wang is based at UCLA and, in addition to his busy practice, runs a basic science laboratory where he is constantly developing and testing new methods to treat spinal disorders.

Recently, Dr. Wang gave SpineUniverse some of his time to help us better understand new biologic materials and the impact they will have on the future of spine surgery.

SpU: Dr. Wang, to begin, what does the term 'biologic material' mean?
Dr. Wang:
A biological material is any substance that actively alters the surrounding environment and effects a change in the environment that progresses through an active, biological process. In other words, the effects are seen through increased cellular activity, growth, and differentiation.

For example, a piece of metal that is often used in a spine fusion procedure, provides stabilization which promotes fusion but, that piece of metal does not stimulate or activate cellular growth or alter cellular function; the metal is an inert material. On the other hand, a protein that attracts more cells to spine fusion can actively increase bone formation and stimulate a spinal fusion. This protein would be considered a biological material.

SpU: Are any biologics currently being used in spine surgery?
Dr. Wang:
Currently, there are many biologics being used in spine surgery. This is probably the most exciting and fascinating development that has occurred in spine surgery. Common biologics in use are the demineralized bone matrices, which are extracts of human bones that biologically help to stimulate bone growth and promote spinal fusion.

Perhaps the most exciting biologics are the bone morphogenetic proteins or BMPs. These proteins are very powerful differentiation factors that can stimulate bone growth and spinal fusion. They are so effective that they can be used instead of the patient's own bone. This spares the patient significant pain, recovery time, and risks of an added procedure.

SpU: Patients are hearing a lot about BMPs. Are any being used by surgeons yet? Are the results encouraging?
Dr. Wang:
BMPs are being used in human spine surgery. The FDA has approved them for use in single-level, anterior spinal fusions, when placed inside of a titanium cage.

Current studies are looking at the use of BMPs in other areas of spinal fusion. The early results of these studies are very encouraging. Since BMPs are so powerful in promoting bone formation, they are being studied for use in all areas of spinal fusion, from the neck to the lower back, and for posterior and even interbody fusions.

SpU: If my doctor plans to use autograft or allograft rather than BMP during my surgery, should I be concerned?
Dr. Wang:
Patients should not be concerned if their surgeon is using allograft or autograft for their surgery. Currently, BMP is not approved for use in many areas of the spine, so the physician is actually providing the best in the standard of care. Allograft bone, especially in the cervical spine, works quite well.

Autograft bone is considered the "gold standard" and is the most commonly used graft for spinal fusion. As we study the results of BMP and other graft replacements, the use of autograft will most likely diminish, being replaced by bone graft substitutes.

SpU: Are there other biologics currently in use that you believe to be significant breakthroughs?
Dr. Wang:
Definitely. Other advances that have enormous potential are the use of stem cells from a patients own bone marrow. Bone marrow cells are removed from the patient and concentrated, applied to a biologically active matrix, and then used as bone graft replacements. This synthetic, biologically active bone can be used for spinal fusion and can replace the need for taking the patient's own bone.

Gene therapy techniques are also being refined for spinal fusion and for disc regeneration. As we advance our knowledge and understanding of the biological processes that are involved in bone formation and disc degeneration, novel biological treatments are being formulated that can provide a better way to treat these spinal disorders, and treat them with less morbidity to our patients.

SpU: During the next 5 years, what other new biologic material developments do you envision?
Dr. Wang:
Over the next 5-6 years, I see several biological material advances that will improve the treatment of spinal disorders. The first area lies in the newer materials that are currently being refined to replace our older, standard materials that we use today. Better metals, stronger metals, and even resorbably bioactive substances will replace current materials. New materials will be used along with some of the biological products that work in conjunction with the newer biologicals.

The next area will come with improved delivery systems for the biological materials. Because they work so well, I envision them being delivered using more minimally invasive techniques with smaller incisions, less pain, and faster recovery periods. In our laboratory, we are using image guidance and minimally invasive techniques to deliver the biological materials. The early results are very encouraging.

The last exciting development lies in extending our therapies into disc regeneration and the refinement of gene therapy techniques. Gene therapy will allow us to overcome many of the limitations of current biological restrictions and allow us to avoid fusions and preserve motion. I think this will be an exciting time for both patients and spine surgeons.

SpU: Thank you for your insights Dr. Wang. We appreciate your time.

Dr. Wang:
You are most welcome.

For information about Dr. Wang’s practice: Click Here