Cervical disc replacement surgery
is a treatment for problematic spinal discs in the neck that cause neck pain or other symptoms such as weakness or pain in the arm.
Replacing a single cervical disc with an artificial disc device has long been an option. But in recent years, two-level cervical disc replacement has been shown to work well for many people with two adjacent damaged or diseased cervical discs.
What is a two-level cervical disc replacement?
During cervical disc replacement surgery, a surgeon removes a damaged or diseased spinal disc in the neck (cervical spine) and replaces it with an artificial disc device.
This procedure can relieve chronic pain and other symptoms caused by pressure on the spinal nerves in the neck. The compression of the nerves may be due to a condition such as a herniated disc
or degenerative disc disease
Artificial discs provide cushioning for the vertebrae, similar to that of the spinal discs. The artificial discs are also designed to maintain more of the natural motion of the spine at that level, making it what’s called a “motion-preserving surgery.”
In a two-level cervical disc replacement surgery, two adjacent damaged or diseased discs in the neck are replaced with two artificial disc devices. This procedure is done for the same reasons as a single-level disc replacement, except at two levels.
How does the procedure work?
The artificial disc device has a metal endplate on the top and bottom, with a plastic disc-like insert between. After the device is implanted, the bone on the adjacent vertebrae grows onto the endplates, which provides stability to the device.
In order for the bone to form a stable connection with the device, a surgeon has to clean out the disc space between the vertebrae. This is done using a small blade to cut the disc and special tools to scrape the cartilage off the surface of the vertebrae.
The surgeon then selects the correct size of the artificial disc and inserts it into the disc space. X-ray imaging is used to make sure the artificial disc is in the right position. For a two-level cervical disc replacement, the same procedure is also done on the adjacent diseased or damaged disc.
Who is a candidate?
Dr. Benjamin Bjerke, a spine surgeon with Capital Orthopaedics & Sports Medicine, PC
, in Clive, Iowa, says that in general, a person who is a good candidate for a one-level cervical disc replacement would also be a good candidate for a two-level cervical disc replacement.
Two-level cervical disc replacement is usually appropriate for people who:
- Are between 20 and 70 years of age. The vertebrae must be mature in order for the device to be implanted.
- Have two damaged cervical discs next to each other (adjacent) from spinal levels C3 to C7.
- Have pain and/or neurological symptoms such as numbness or weakness in the arms. They may or may not have neck pain.
- Have symptoms due to a diseased or damaged disc. This needs to be confirmed by a surgeon using CT, MRI, or X-ray images.
- Did not respond to at least six weeks of non-surgical care such as physical therapy or medications. If the symptoms worsen even with medical treatments, a surgeon may suggest artificial disc replacement before six weeks.
Who is not a candidate?
While two-level cervical disc replacement is an option for many people, it may not work for people with certain conditions.
“In general, patients with severe neck pain, [spinal] instability, advanced degeneration, or arthritis are not good candidates for any cervical disc replacement,” says Bjerke.
In addition, two-level cervical disc replacement is not recommended for people with any of the following:
- An active infection in the body
- Weakened bones (osteoporosis or osteopenia)
- Allergy to the materials found in the artificial disc device
- Advanced spinal degeneration, including degeneration of the facet joints on the back of the spine
- Instability in the cervical spine, such as from a prior injury or surgery
- Other diseases or conditions that affect the cervical spine
What are the risks of this surgery?
The risks of two-level cervical disc replacement surgery include:
- General surgical risks, such as infection, continued bleeding after surgery, or a bad reaction to the drugs used during the surgery (such as the anesthesia)
- Hoarseness or difficulty talking or swallowing
- Numbness, tingling, or weakness in the arm
- Damage to the spinal cord or the nerves at the back of the spine
- Need for later removal of the device or a second surgery to fix a problem with the implant
- Placement of the device at the wrong level of the spine or in the wrong position
- Movement of the device after surgery
- Breakage or wearing down of the device
- Development of poor stability at the spinal level where the device was implanted, or at other levels
These risks also occur with one-level cervical disc replacement surgery, but some of the risks are higher when two discs are replaced.
“A two-level cervical disc replacement will almost double the operation time required,” says Bjerke, which can increase the risks involved.
“One of the most important [risks] is dysphagia (difficulty swallowing),” he says. “This is noted to be increased with prolonged surgery, and is generally more of a problem [after two-level cervical disc replacement].”
Which cervical artificial discs are FDA approved?
Currently, three artificial disc devices are approved by the U.S. Food and Drug Administration for use in a two-level cervical disc replacement:
- NuVasive Simplify
- Prestige LP
What is the success rate of two-level cervical disc replacement?
Two-level cervical disc replacement surgery has shown similar or better overall success rates as spinal fusion surgery. Overall success is a measure of several factors related to the safety of the device and how well it works. This includes changes in neck pain and neurological symptoms such as numbness or weakness in the arms, as well as whether there are complications after surgery or whether the device fails.
- The Prestige LP Cervical Disc, when used at two levels, had an overall success rate after 10 years of 80.4%, compared to 62.2% for spinal fusion at two levels. Two-level disc replacement also required fewer follow-up surgeries (4.7%) than spinal fusion (17.6%).
- After seven years, the Mobi-C Cervical Disc had an overall success rate of 60.8% when used at two levels, compared to 34.2% for a two-level spinal fusion. There were also fewer secondary surgeries after disc replacement (3.7%) than after spinal fusion (13.6%).
- The NuVasive Simplify Cervical Artificial Disc for two levels had an overall success rate after two years of 86.7%, compared to 77.1% for spinal fusion at two levels.
Is a two-level cervical disc replacement better than a fusion?
Two-level cervical disc replacement is a newer surgery than one-level cervical disc replacement, so fewer studies have looked at the benefits, including the longer-term benefits.
However, the data for two-level cervical disc replacement is “certainly encouraging at this point,” says Bjerke, “and the results so far are similar to a one-level disc replacement.” This includes a lower risk of problems at nearby levels, a lower need for a second surgery afterward, and improved patient satisfaction.
How long is the recovery time for two-level cervical disc replacement?
Recovery after two-level cervical disc replacement is similar to after single-level disc replacement, although it can take longer because two discs were replaced.
After a two-level disc replacement, most people will spend one or two days in the hospital recovering. They will be allowed to go home once they are able to walk up and downstairs, eat solid foods, and have a bowel movement.
Most people can resume everyday activities, such as driving and light work, within one week after surgery. A full recovery takes 6 to 12 weeks. After this point, most people will be able to lift heavy objects and do vigorous activities.
However, for some people who had severe compression of the nerve before surgery, it can take up to two years for the nerve to fully heal.
Two-level cervical disc replacement is similar to a one-level cervical disc replacement. In this case, though, two adjacent damaged or diseased discs are replaced rather than one.
Both surgeries have similar risks, although because two-level cervical disc replacement takes longer, some of these are higher than after a one-level surgery.
As with one-level cervical disc replacement, two-level replacement has been found to have a higher overall success rate than two-level spinal fusion, with a lower need for a secondary surgery.
Bjerke recommends that people who are offered a two-level spinal fusion talk with their surgeon about whether two-level disc replacement might be an option for them — or find out why the surgeon would not recommend disc replacement.
“If you are not satisfied with the answer, or believe that your surgeon may not be favorable to disc replacement surgery, a second opinion is always a good idea,” he says.
Updated: June 11, 2021