Artificial Cervical Disc
September, 2007FDA-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.
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
Development or progression of disease at other cervical levels
Implants that bend, break, loosen or move
Loss of motion at the treated cervical level
Numbness of tingling in the extremities
Pain or discomfort
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.
Copyright 2007 Neurosurgerytoday.org