Patent Application
20140276591
1. Field of the Invention
This invention relates generally to a device and method for providing annular fibrosus regeneration of an intervertebral disc and, more particularly, to a device and method for providing annular fibrosus regeneration of an intervertebral disc using a biochemical, biological and/or synthetic material provided between the nucleus pulposus and the annulus fibrosus to seal annular tears.
2. Discussion of the Related Art
An intervertebral disc is a layer of cartilaginous material that stabilizes the spine and distributes forces between vertebrae. The intervertebral disc consists of an outer annulus fibrosus and an inner nucleus pulposus. The annulus fibrosus is made of strong lamellar layers of collagen fibers woven together at different angles, which provide withholding structures to the disc to keep the inner nucleus pulposis from herniating and allow for even force distribution among the surrounding vertebrae. The annulus fibrosus contains and protects the fluid, gel-like nucleus pulposus inside the disc. On the other hand, the nucleus pulposus consists of chondrocytes, collagen fibrils, and proteoglycan aggrecans which provide the capacity to bind water and support the adjacent vertebrae. The nucleus pulposus acts as a shock absorber, absorbing the impact of the body's daily activities while allowing movement of the adjacent vertebrae.
An intervertebral disc may be displaced or damaged due to trauma, disease, general wear and tear, or even age. Over time, the annulus fibrosus loses flexibility and elasticity; and the nucleus pulposus loses hydration, thus causing the interverterbral disc to lose height and leading to instability, tear or rupture. When a disc tears or ruptures, the disruption of the annulus fibrosis may allow the nucleus pulposus to bulge out into the vertebral canal, a condition commonly referred to as a herniated disc (also known as ruptured disc or slipped disc). The bulged out nucleus pulposus may press onto the spinal nerve and release inflammatory chemical mediators, which may result in nerve damage, pain, numbness, muscle weakness, and paralysis. If the herniated disc is in the lumbar region, the patient has a high possibility of experiencing sciatica that involves lower back and leg pain. Sciatica is the most common symptom of a lower back herniated disc, due to irritation of one of the nerve roots of the sciatic nerve while allowing movement of the adjacent vertebrae. Additionally, discogenic pain, i.e., pain originating from the intervertebral disc, can result in debilitating back pain even in a situation where there is no significant disc bulge or herniation. Patient's with discogenic back pain often experience debilitating pain and cannot work or perform activities of daily living.
A method that can be used to identify the source of intervertebral discogenic pain is a discography. In this procedure, dye is injected into the disc and the patient is asked whether he or she is experiencing a similar sort of back pain or not. This is followed by a computer tomography (CT) scan that shows if the injected dye is leaking out into the spinal canal. The leakage of dye is through tears in the annulus fibrosis. In many cases the patient's origin of pain is from the intervertebral disc level with concordant pain and annular tears, reflected by the egress of dye into the spinal canal as seen on the CT scan. These levels are usually treated by spinal fusion with removal of the intervertebral disc. In contrast, normal appearing discs do not generate much pain with injection of the dye, and show an intact annulus fibrosis, i.e., the dye stays within the center of the disc. It is believed that annular tears allow inflammatory factors to exit through the annulus and irritate the adjacent neural elements, and thus result in the back pain symptoms.
Herniated discs can occur in any part of the spine, but the majority of herniated disc occur in the lumbar region (lower back), while the second most common site is the cervical region (neck), and then the thoracic region (upper back) only accounts for a small percentage.
A herniated disc is often diagnosed through imaging, such as a magnetic resonance imaging (MRI) or a CT scan. In most cases, a herniated disc does not require surgery because it will heal on its own over time with rest. Approximately about half of the people with a herniated disc will improve within one month, while others will see improvement within six month. Despite the high improvement rates, about one in ten patients still requires surgery.
Initial non-surgical treatment serves to reduce pain and inflammation, and usually consists of non-steroidal anti-inflammatory pain medication; however, the long-term use of such medication may result in cardiovascular and gastrointestinal toxicity. An alternative treatment is to inject cortisone, a steroid hormone, into the spine to ease the pain. Nevertheless, these types of injection may still result in serious complications with long-term use. Other non-surgical treatments include physical therapy, chiropractic manipulation, anti-depressant, and other exercise programs.
If the condition continues to deteriorate, the last resort is surgery. The most common and effective surgery for herniated disc is a discectomy. A discectomy is the surgical removal of the herniated disc and more specifically, the nucleus pulposus that presses the nerve root or the spinal cord. Aside from the common surgical risks involving infection, anesthesia, and damages to the spine or nerves, the removal of the herniated disc may allow the disc space to collapse. A collapsed disc space will lead to instability of the spine, abnormal joint mechanics, nerve damage, and severe pain.
In recent years, intradiscal electrothermal annuloplasty (IDET), a minimally invasive form of herniated disc treatment, has been introduced. IDET includes the process of inserting a percutaneous threading of a flexible catheter into the herniated disc under fluoroscopic guidance. The catheter is composed of thermal resistive coil. Once the percutaneous catheter has reached the disc, the thermal resistive coil is heated to about 90° C. The heat shrinks and thickens the disc wall's collagen fibers for sealing any ruptures in the disc wall, and the heated coil may also used for burning nerve endings, which reduces pain by making the area less sensitive to pain. Studies have shown that IDET can relieve pain and improve mobility with an approximately 55% success rate, but the healing process takes time. Furthermore, the efficacy of IDET has not been assessed in randomized controlled clinical trials. This treatment technique has largely been abandoned due to poor clinical outcomes and non-reimbursement by insurance companies.
There is a need for treating a herniated disc less invasively and with a higher success rate while restoring the integrity of the annulus fibrosis and maintaining the nucleus pulposus.
In accordance with the teachings of the present invention, a regeneration device and method for sealing annular tears between the nucleus pulposus and the annulus fibrosus of an intervertebral disc is disclosed. The regeneration device includes a trocar having a sharp tip at a distal end, an inner cavity, and a handle portion attached to a proximal end of the trocar. The device further includes a plunger coupled to a catheter that extends through the inner cavity. The regeneration method includes inserting the trocar into an intervertebral disc via Kambin's triangle, and once the trocar reaches the nucleus pulposus, the catheter is extended alongside the annulus fibrosus wall to surround the nucleus pulposus. A syringe is mounted to the plunger and injects a biochemical, biological and/or synthetic material through multiple ports in the catheter to form a collagen or collagen like barrier that prevents the nucleus pulposus from protruding through the annulus fibrosus.
Additional features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.
The following discussion of the embodiments of the invention directed to a device and method for providing annular regeneration is merely exemplary in nature, and is in no way intended to limit the invention or its application or uses.
The foregoing discussion discloses and describes merely exemplary embodiments of the present invention. One skilled in the art will readily recognize from such discussion and from the accompanying drawings and claims that various changes, modifications and variations can be made therein without departing from the spirit and scope of the invention as defined in the following claims.
This application claims the benefit of the priority date of U.S. Provisional Patent Application No. 61/783,935, titled Percutaneous Intervertebral Annular Regeneration, filed Mar. 14, 2013.
| Number | Date | Country | |
|---|---|---|---|
| 61783935 | Mar 2013 | US |
