Devices and methods for the treatment of spinal disorders

Abstract

Devices and methods for treating a damaged intervertebral disc to reduce or eliminate associated back pain. Dynamic bias devices and reinforcement devices are disclosed, which may be used individually or in combination, to eliminate nerve impingement associated with the damaged disc, and/or to reinforce the damaged disc, while permitting relative movement of the vertebrae adjacent the damaged disc.

Description

FIELD OF THE INVENTION [0001] The present invention generally relates to spinal implants. Specifically, the present invention relates to implantable devices and methods for the treatment of spinal disorders associated with the intervertebral disc. BACKGROUND OF THE INVENTION [0002] Back pain is one of the most common and often debilitating conditions affecting millions of people in all walks of life. Today, it is estimated that over ten million people in the United States alone suffer from persistent back pain. Approximately half of those suffering from persistent back pain are afflicted with chronic disabling pain, which seriously compromises a person's quality of life and is the second most common cause of worker absenteeism. Further, the cost of treating chronic back pain is very high, even though the majority of sufferers do not receive treatment due to health risks, limited treatment options and inadequate therapeutic results. Thus, chronic back pain has a significantly adverse...

AI Technical Summary

Benefits of technology

[0015] As will become apparent from the following description, the improved devices and methods of the present invention reduce if not eliminate back pain while maintaining near normal anatomical motion. Specifically, the present invention provides dynamic bias devices and reinforcement devices, which may be used individually or in combination, to eliminate nerve impingement associated with a damaged disc, and / or to reinforce a damaged disc, while permitting relative movement of the vertebrae adjacent the damaged disc. The devices of the present invention are particularly well suited for minimally invasive methods of implantation.

[0016] The dynamic bias devices of the present invention basically apply a bias force to adjacent vertebrae on either side of a damaged disc, while permitting relative movement of the vertebrae. By applying a bias force, disc height may be restored, thereby reducing nerve impingement. Specifically, by restoring disc height, the dynamic bias devices of the present invention: retract disc protrusions into the normal disc space thereby reducing nerve impingement by the protrusions; reduce the load carried by the facet joints thereby eliminating nerve impingement originating at the joint; restore intervertebral spacing thereby eliminating nerve impingement by the intervertebral foramina; and reduce pressure on portions of the annulus thereby alleviating nerve impingement in disc fissures.

[0017] The reinforcement devices of the present invention basically reinforce a damaged disc, restore disc height and / or bear some or all of the load normally carried by a healthy disc, thereby reducing nerve impingement. Some embodiments of the reinforcement members of the present invention have a relatively small profile when implanted, but are very rigid, and thus serve to reinforce the disc, particularly the annulus. By reinforcing the disc, and particularly the annulus, disc protrusions may reduced or prevented, thereby eliminating nerve impingement by the protrusions. Other embodiments have a relatively large profile when implanted, and thus serve to increase disc height and / or to bear load. By increasing disc height, the advantages discussed previously may be obtained. By bearing some of the load normally carried by a healthy disc, the load may be redistributed as needed, such as when a dynamic bias device is used.

Problems solved by technology

Back pain is one of the most common and often debilitating conditions affecting millions of people in all walks of life.

Approximately half of those suffering from persistent back pain are afflicted with chronic disabling pain, which seriously compromises a person's quality of life and is the second most common cause of worker absenteeism.

Further, the cost of treating chronic back pain is very high, even though the majority of sufferers do not receive treatment due to health risks, limited treatment options and inadequate therapeutic results.

Thus, chronic back pain has a significantly adverse effect on a person's quality of life, on industrial productivity, and on heath care expenditures.

For example, some forms of lower back pain (LBP) are very common and may be caused by unusual exertion or injury.

Unusual exertion such has heavy lifting or strenuous exercise may result in back strain such as a pulled muscle, sprained muscle, sprained ligament, muscle spasm, or a combination thereof.

An injury caused by falling down or a blow to the back may cause bruising.

For example, being pregnant, obese or otherwise significantly overweight may cause LBP.

A mattress that does not provide adequate support may cause back pain in the morning.

Working in an environment lacking good ergonomic design may also cause back pain.

However, some forms of back pain are chronic and are the result of spinal disorders which are not readily treated.

Such spinal disorders may cause severe back pain, the origin of which may or may not be certain.

Another clinical theory is that damage to the disc, either from injury, degradation or otherwise, causes physical impingement of the disc nerves, which are primarily disposed about the periphery of the annulus, but may grow into fissures of a damaged disc.

Physical injury may cause damage to the annulus fibrosus which allows a portion of the disc, such as the nucleus pulposus, to protrude from the normal disc space.

In either case, the disc protrusion may impinge on a spinal nerve root causing severe pain.

Posterior protrusions are particularly problematic since the nerve roots are posteriorly positioned relative to the intervertebral discs.

However, discectomy procedures have an inherent risk since the portion of the disc to be removed is immediately adjacent the nerve root and any damage to the nerve root is clearly undesirable.

Furthermore, discectomy procedures are not always successful long term because scar tissue may form and / or additional disc material may subsequently protrude from the disc space as the disc deteriorates further.

The recurrence of a disc protrusion may necessitate a repeat discectomy procedure, along with its inherent clinical risks and less than perfect long term success rate.

Thus, a discectomy procedure, at least as a stand-alone procedure, is clearly not an optimal solution.

Discectomy is also not a viable solution for DDD when no disc protrusion is involved.

If the facet joints carry a substantial load, the joints may degrade over time and be a different cause of back pain.

Such nerve impingement is very painful and cannot be corrected by a discectomy procedure.

However, the success rate of spinal fusion procedures is certainly less than perfect for a number of different reasons, none of which are well understood.

In addition, even if spinal fusion procedures are initially successful, they may cause accelerated degeneration of adjacent discs since the adjacent discs must accommodate a greater degree of motion.

The degeneration of adjacent discs simply leads to the same problem at a different anatomical location, which is clearly not an optimal solution.

Furthermore, spinal fusion procedures are invasive to the disc, risk nerve damage and, depending on the procedural approach, either technically complicated (endoscopic anterior approach), invasive to the bowel (surgical anterior approach), or invasive to the musculature of the back (surgical posterior approach).

This procedure is also very invasive to the disc and, depending on the procedural approach, either invasive to the bowel (surgical anterior approach) or invasive to the musculature of the back (surgical posterior approach).

In addition, the procedure may actually complicate matters by creating instability in the spine, and the long term mechanical reliability of prosthetic discs has yet to be demonstrated.

However, many of the proposed procedures have not been clinically proven and some of the allegedly beneficial procedures have controversial clinical data.

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