Chronic Lower Back Pain afflicts an estimated 33 million people annually in the U.S. Over 7 million of those people suffer from Degenerative Disc Disease. Aging baby boomers may double those numbers in the next two decades.
Back pain is strongly associated with degeneration of the intervertebral disc. Disc degeneration, although in many cases asymptomatic, is also associated with sciatica and disc herniation or prolapse. It alters disc height and the mechanics of the rest of the spinal column, adversely affecting the behavior of other spinal structures such as muscles and ligaments. In the long term, it can lead to spinal stenosis, a major cause of pain and disability in the elderly. Degenerated disc incidence is rising with current demographic changes and an increased aged population.
The original treatment for correcting degenerated disc is either to perform a discectomy or spinal fusion. Discectomy is surgery to remove one or more discs from the spine. Usually, a discectomy is combined with a fusion of the two vertebrae that are separated by the disc. In some cases, this procedure is done without a fusion. Discectomy is an appropriate procedure and is routinely performed to remove the degenerated nucleus. Although this procedure is ideal for decompressing and relieving the nervous system, it can be a poor long-term solution for the spine, because it creates a potentially disabling condition that leads to a degenerative cascade which may require an additional invasive surgical procedure, like fusion or arthroplasty. Discectomy brings a good short-term effect in relieving radicular pain, but it causes disc height reduction with neuro-foramen stenosis, creating instability of the treated level, and an eventual increase in back pain, and/or complications, such as spinal stenosis or facet pain.
Those patients who go through these procedures are usually on painkillers for weeks and have at least three to six months of recovery time. Therefore, the medical community has been investigating efforts to find a less painful, less invasive and more effective method.
Current temporary treatments attempt to reduce pain rather than repair the degenerated disc. The treatments used presently are mainly conservative and palliative, and are aimed at returning patients to work. Legacy treatments range from bed rest (no longer recommended) to analgesia, the use of muscle relaxants or injection of corticosteroids, or local anesthetic and manipulation therapies. Various interventions (e.g. intradiscal electrotherapy) are also used, but despite anecdotal statements of successful trials, have thus far found their use to be of little direct benefit. Disc degeneration-related pain is also treated surgically long-term by immobilization of the affected vertebrae, using implantable mechanical devices. These devices have a distinct disadvantage since they are not autologous (patient generated) and can create undue stress above and below the implanted disc.
Typically, disc damage and articular cartilage are not naturally regenerated once damaged. The failure of the current treatment procedures with immobility devices has led to a search for non-fusion technologies, such as disc or disc nucleus prosthesis. Disc arthroplasty with an artificial disc is an emerging treatment. Its advantages are to maintain motion, decrease incidence of adjacent segment degeneration, avoid complications related to fusion, and allow early return to function. Today, two kinds of devices are marketed: the total disc replacement and the nuclear replacement, but both have major pitfalls.
Our invention provides a new and uniquely patented regenerative device and alternative method for repairing the cartilage of the intervertebral disc (or any other articular cartilage). The method is based on using Human Dermal Fibroblasts (HDFs) that are forced to differentiate into chondrocyte-like cells in vivo through mechanical force, and the Intermittent Hydrostatic Pressure (IHP) critical for chondrogenic differentiation of fibroblasts.
Recently, efforts have been made to reconstruct damaged biological tissues by regenerating a portion of the damaged tissues in laboratories. This approach, defined as “tissue engineering” has raised tremendous attention, and is the core focus of our invention.