Stem Cells and Degenerative Disc Disease
SpineUniverse.com interviewed Kaliq Chang, MD—an anesthesiologist and pain management specialist about stem cells in the treatment of degenerative disc disease.
Q. Dr. Chang, what are stem cells?
Dr. Chang: There are several different types of stem cells that are used in the emerging field of regenerative medicine. Stem cells are attached to blood vessels and when a blood vessel is broken, such as during an injury, stem cells are released to help repair the damage and heal the body. Stem cells found in bone marrow have been used successfully for 20 years to treat certain disorders affecting the hips, knees and shoulders. Also called mesenchymal stem cells, these cells have the unique ability to orchestrate the healing and regrowth of cells that are lost through injury, aging or normal wear and tear.
Q. What is degenerative disc disease?
Dr. Chang: The spine is comprised of alternating vertebrae (bones) and discs that work to absorb and distribute pressure and stress when a body is active or at rest. The majority of the body's weight absorption and distribution is handled by the low back or lumbar spine—a common spinal region where degenerative disc disease may develop.
As a person grows older, the natural process of aging (degeneration at the cellular level) can progressively change and affect the strength and structure of one or more intervertebral discs. Discs that are normally plump with water may begin to dry out affecting their shock-absorbing capacity. Sometimes a disc may rupture (herniated disc) and release proteins that irritate fragile spinal nerve roots causing inflammation and pain.
Q. Why and how are stem cells used to treat degenerative disc disease?
Dr. Chang: Studies show that adult stem cells (also called non-embryonic stem cells) may be effective in relieving back pain caused by degenerative disc disease. Unlike other tissues in the body, the spine's discs have a very limited blood supply. In other words, a disc affected by the degenerative effects perhaps related to aging and/or wear and tear may not be able to repair itself. Stem cells are unique in their ability to help repair damage. They can be inserted (via injection) into a damaged disc to help promote healing.
Stem cells can regenerate the formation of fibrous connective tissue (eg, ligaments) making them ideal for helping to repair soft tissue damage caused by degenerative disc disease. The highest level of stem cell concentration is found in adult bone marrow (eg, hip bone).
Q. Is stem cell therapy for all patients with DDD?
Dr. Chang: Good candidates for this procedure have pain that has not responded to conservative treatment methods such as physical therapy, over-the-counter medications and epidural injections. These patients have received a diagnosis of degenerative disc disease confirmed by physical examination and MRI.
The best candidates tend to be younger patients who have experienced some sort of injury to an isolated area of the back involving one or two discs. Older patients tend to have more wide-spread DDD.
Q. How are stem cells obtained?
Dr. Chang: The process of obtaining stem cells is called harvesting. The harvesting of stem cells from the hip bone of adults is approved by the U.S. Food and Drug Administration.
Pain is controlled by administration of a local anesthetic. Sedation (eg, twilight sleep) is an option. Obtaining stem cells is a sterile procedure performed by a physician using fluoroscopy—a type of real time medical imaging. Fluoroscopy is similar to a snapshot of a specific part of the patient's spine, and is used to help guide placement of the needle into the hip bone. Once the needle is properly placed, an appropriate amount of bone marrow is extracted and placed into a centrifuge to separate the cellular components. In short, the process produces a highly-concentrated substance containing the stem cells.
Post procedure discomfort is treated using an ice pack and over-the-counter acetaminophen.
Q. How do you determine where to place the stem cells in the patient's spine?
Dr. Chang: To be sure we are repairing the right disc we first need to pinpoint the exact source of the pain through a procedure known as a provocative discography. During this sterile procedure under fluoroscopic guidance, needles are inserted through the patient's backside into the "suspect" disc. Fluid is injected into the "suspect" disc and the patient's pain responses are carefully noted. Discography may replicate the patient's pain type and pattern and can help to target the source of pain and symptoms.
Q. What are the potential risks and benefits of stem cell therapy?
Dr. Chang: The risks are the same as with any medical procedure (eg, bleeding, infection). We go to great lengths to protect the sterility of the environment because infection in the spine can be very serious.
Patients are advised that the pain following the procedure may feel worse than the pain from degenerative disc disease. That's because we're inserting volume into an area that is very sensitive. This pain is normal. Usually, about the third week after the procedure, most patients report pain relief. Progressively, more pain relief continues for about three months. Studies have shown that 75% of patients have relief for up to two years.
Treating degenerative disc disease with the patient's own stem cells takes advantage of the body's ability to heal itself naturally. Once the stem cells have been added to the disc, the disc will most likely function without pain.
Stem cell treatment may be preferred to the other DDD treatments, such as surgery to remove one or more damaged discs, replacing the damaged disc with an artificial device or fusion. However, it is important to understand that degenerative disc disease may cause spinal instability or neurological dysfunction requiring a surgical intervention.
Closing Comments by Dr. Chang
One possible long-term risk of stem cell treatment is tumor growth caused by an uncontrolled proliferation of stem cells. However, this seems more of a concern when embryonic stem cells are used. Embryonic cells can continue dividing (growing in number) and take on characteristics of cancer cells.
In some animal studies, the development of tumors has resulted. To date, the proliferation issue is less of a concern with adult stem cells, since they seem to have a preset limit to how many times they divide.
There have been no long-term adverse effects reported and the procedure may also reverse the effects of aging and wear and tear on the spine. I believe adult stem cells will soon become the gold standard in treating disc degeneration, although this is an emerging field.