Artificial Cervical Disc
September, 2007
FDA-Approved Artificial Cervical Disc
The PRESTIGE® cervical disc, a product of Medtronic, is the
first and only artificial disc to be approved by the Food and Drug
Administration (FDA) for use in the cervical spine, as of July 2007. The
PRESTIGE disc is indicated for spinal arthroplasty in skeletally mature
patients with degenerative disc disease at one level from C3 to C7, for
intractable radiculopathy and/or myelopathy. This is a stainless-steel
device with a ball-in-trough design, held in place with bone screws.
The BRYAN® cervical disc, also a product of Medtronic,
has undergone clinical trials, and is currently progressing through the
various FDA panel discussions required prior to approval. In general,
the pre-approval process can take several years.
Artificial Disc Surgery
Currently, the most common form of surgery for treating
cervical degenerative disc disease is an anterior cervical discectomy
and fusion (ACDF). More than 200,000 cervical procedures are performed
each year to relieve compression on the spinal cord or nerve roots.
Spinal fusion surgery creates a solid union between two or more
vertebrae to help strengthen the spine and alleviate chronic neck pain.
There are several types of spinal fusion surgery, as well as varied
instrumentation used to secure the fusion.
The goals of artificial cervical disc surgery are to:
1) Remove the diseased disc; 2) Restore normal disc height; 4) Decrease
discogenic neck pain and associated arm pain/weakness; 4) Preserve
motion in the affected vertebral segment; and 5) Improve patient
function. In comparison to spinal fusion surgery, potential benefits of
artificial disc technology may include more spine mobility after surgery
and less stress on adjacent discs. While cervical artificial discs have
been shown to preserve motion at the operated segment in most patients,
their effectiveness in reducing the rate symptomatic adjacent disc
problems has not been established.
To be considered a candidate for artificial cervical
disc, you must meet the following specific criteria:
- Disc degeneration in only one disc in the cervical
spine.
- A minimum of six months of conservative treatment,
such as physical therapy, pain medication, or neck bracing, without
showing improvement.
- Overall good health with no signs of infection,
osteoporosis, arthritis, or osteomalacia
- No known allergies to stainless steel.
If you have degeneration affecting more than one disc,
segmental instability, any type of metabolic or hereditary/acquired
bone disease, you are not a candidate for this surgery. This surgery is
not recommended in patients who have undergone prior spinal
fusion/surgical procedures at the same or adjacent cervical levels.
During surgery, the patient is under general
anesthesia and a small incision is made in the front of the neck.
Through this opening, the affected disc is removed and replaced. The
average hospital stay postoperatively is about 1-2 days. Although a
similar artificial cervical disc has been used in Europe since 2004,
there is very little information available on the number of surgeries
performed to date.
Potential complications
Need for additional surgery
Allergic reaction to the
implant materials
Altered mental state
Bleeding; may require a
blood transfusion
Blood vessel problems other than bleeding
Death
Development
or progression of disease at other cervical levels
Implants that
bend, break, loosen or move
Incision problems
Infection
Loss
of motion at the treated cervical level
Numbness of tingling in the
extremities
Pain or discomfort
Paralysis
Side effects from
anesthesia
Spinal cord or nerve damage
Spinal fluid leakage
Tears
of the dura (a layer of tissue covering the spinal cord)
Outcome
Some of the
potential risks of artificial disc surgery are common to many other
types of surgery, in particular spine surgeries. Although some patients
who have undergone spinal fusion surgeries need revision surgeries, they
are generally less problematic than those after artificial disc
surgery. There is much debate among the medical community about the
efficacy of artificial cervical disc surgery.
In the largest clinical trial study ever completed in
the cervical spine involving 541 patients, results demonstrated that the
PRESTIGE cervical disc had comparable outcomes to the current standard
treatment of spinal fusion.
As part of the FDA approval conditions, Medtronic
agreed to conduct a seven-year post approval study to evaluate long-term
safety and effectiveness. Medtronic will also be performing a five-year
enhanced surveillance study.
Implanted metal alloys release metallic ions into the
body (especially those devices with metal-on-metal articulating
surfaces). The long-term effect of these ions on the spine is currently
unknown. Long-term patient monitoring is essential to properly assess
how effective and safe artificial disc surgery is in comparison to
spinal fusion surgery. While the artificial disc is groundbreaking, new
technologies are in development that may have the potential to improve
upon this surgical technique.