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NeuroCare Brain & Spine Center™ - Research
Artificial disc technology, or disc replacement is the subject of many research
studies throughout the scientific world at this time.
It is well documented that the spine undergoes aging changes throughout a
lifetime. Over time, both the vertebrae (bones of the spine) and discs (cushions
between the vertebrae) accept the effects of weight bearing. The result is often
what is called a degenerative condition of the discs.
As a disc degenerates the vertebrae move closer together. This changes the way
that the disc and the vertebrae share the load of spinal motion. As the body
works to heal from this shift of load, bone spurs called ostephytes form.
Degenerative Disc Disease (DDD) thus describes a normal process of aging, and is
not really a true “disease”. But, nevertheless it can be a painful and
debilitating process.
In the cervical spine, degenerative changes of the discs and the formation of
osteophytes can cause compression of the nerves or spinal cord. The symptoms
from this compression are called radiculopathy (nerve root compression) or
myelopathy (spinal cord compression).
Radiculopathy is a set of symptoms associated with a specific nerve root path.
In the cervical spine it includes arm pain, weakness, and changes such as
numbness and/or tingling in the arm or hand. Fortunately for most patients with
radiculopathy, there is usually improvement over time and devastating
consequences are rare. For those that do not improve with time, indications for
surgical treatment are pain that cannot be controlled with medications or
therapy or weakness that gets worse instead of better within a reasonable period
of time without surgery.
 Myelopathy,
the symptoms of spinal cord compression, usually appears gradually with
progression over a prolonged period of time. Patients rarely improve without
treatment and the symptoms usually continue to get worse. For this reason, early
surgery to decompress the spinal cord is recommended to stop disease
progression.
One surgical procedure used to treat cervical radiculopathy or myelopathy is
called an Anterior Cervical Discectomy and Fusion. (ACDF) It has been a
well-accepted procedure for the treatment of disc disease in the cervical spine
since the 1950s.
In ACDF, compression of the nerves or spinal cord is relieved at the involved
level as the disc is removed (discectomy). Any bone spurs are also removed. Bone
or synthetic material is placed as a graft for fusion between the vertebrae to
maintain spacing between them. Maintaining spacing prevents narrowing of the
exit paths for the nerves leaving the spine. As added stability while the body
“fuses” the graft, an ACDF can include internal fixation (plating). Plating
provides immediate stability and allows the patient to begin light activities
soon after surgery.
Each year in the United States, approximately 175,000 anterior cervical
discectomy and fusion surgeries for disc disease are performed. Although these
procedures are very effective at alleviating symptoms and improving neurological
function they also bring an unwanted side effect of shifting additional burden
in the spine to the adjacent, un-fused spinal levels. This shift can increase
the rate of degeneration of other discs in the spine. This shift of burden has
been linked to the need for additional surgeries in the future for patients.
The suggestion that having a spinal fusion will increase the likelihood of
additional surgery in the future has spurred an interest in what is called
motion preservation surgery. In motion preservation surgery, a disc and
osteophytes are removed to take pressure off of the nerves or spinal cord, and
instead of a fusion that stops motion, another technique is used to allow
continued motion of the spine. One option for motion preservation is what is
called disc replacement or artificial disc technology (disc arthroplasty).
Disc arthroplasty for the lumbar spine (low back) has been used in Europe since
the 1980s and was recently approved for use in the U.S. Enthusiasm for disc
replacement in the cervical spine came about in the late 1990s.
Aurora BayCare Medical Center is preparing for a research study involving disc
arthroplasty for the cervical spine and the
Wallis System designed to treat the pain caused by degenerative disc
disease.
NeuroCare Brain and Spine Center™
(920) 288-8020
Toll-free (877) 577-5800
2845 Greenbrier Road
P.O. Box 8900
Green Bay, WI 54308-8900
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