|Dr. Rick Sasso|
That's a great question. Theoretically, a fusion will lead to increase stresses and strains at the levels above and below that fusion. And the concern is that those increased stresses actually may lead to accelerated degeneration or wearing out at the levels above or below that fusion. The problem is trying to differentiate that acceleration from the natural history of disc degeneration. Obviously, if you've had a fusion it's because you've had degeneration of that disc and it's more likely that you're going to have degeneration at other levels than someone who doesn't have a lot of disc degeneration.
|Dr. Sean Salehi|
In a minority of patients it can lead to symptomatic adjacent level disc degeneration.
|Dr. Kevin Yoo|
Fusion helps with neck pain, but it also transfers the stress from motion, which the affected disc space used to withstand prior to being fused, to the adjacent vertebrae.
|Dr. Paul Saiz|
The general thinking is that there is increased stress around the adjacent discs surrounding a fusion. Over time, these discs will work harder and move more to make up for the fused segment. The general thinking is that this will eventually cause these remaining motion segments to wear out.
|Dr. Dennis G. Crandall|
Fusing the spine does increase the stress seen by the adjacent disks and joints. Whether this added stress translates into a new source of pain or instability is harder to predict.
|Dr. Jeffrey Goldstein|
New York, NY
There is some evidence that people who have an abnormal disc above or below the level of the fused segment can go on to develop problems. Although we're not sure what that risk is, it's fairly low. If the disc is very abnormal it may be included in the fusion and in the stabilization process to prevent that from happening. Although we're not sure whether that risk is 5% or 20% it's still reasonably low. But, if the disc is normal above and below the fused level, then the risk of having a problem at that level should not be significantly higher than it would if you had not had surgery.
|Dr. David S. Baskin|
This is a good question, and one that doctors discuss amongst themselves. The concern is that if one area is fused together, this may place more stress on the other discs and joints and cause them to deteriorate more rapidly. The evidence suggests that this is not usually a problem in the cervical spine, as the weight of the head is not excessive. In the low back, which bears most of the body weight, this is a concern.
|Dr. Brian Subach|
A fusion may cause additional stress at adjacent levels of the spine. Such stress may speed deterioration of the discs at these levels.
|Dr. Allan Levi|
Fusion performed at one or multiple levels does have potential to result in accelerated degeneration at cervical levels either above or below the level of fusion. While the risk of accelerated degeneration at these levels exists, it must be compared to degenerative disc disease, which tends to attack multiple levels.
|Dr. Daniel Resnick|
A fusion will eliminate the motion at a disc space. The spine was designed to have motion at each of the individual disc spaces so eliminating the motion at one disc space will cause increased motion and increased stress at adjacent disc spaces. It is thought that this increased stress can accelerate the degenerative changes seen at other levels in the cervical spine, however this theory really has not been proven to anyone's satisfaction.
|Dr. Robert S. Pashman|
Los Angeles, CA
That is an excellent question. In a single-level fusion, there is little impact on the spine. In a multi-level fusion, the major concern about performing a fusion is adjacent-segment degeneration. The discs act as shock absorbers between the vertebrae. When the spine is fused, the levels above or below the fusion may absorb the sheer force from everyday motion, and thus wear out the discs. When fusion is performed with the appropriate size bone graft, the balance of the spine is maintained and the adjacent segments are at less risk of degeneration.
|Dr. Randy Davis|
Glen Burnie, MD
The benefits of the fusion procedure are often very gratifying in terms of decreasing pain and disability. A fusion does, however, put extra stress at other levels which are not fused and it is thought that the incidence of getting degeneration at other levels next to a fusion is about 2-3% a year. Thus, 10 years after a fusion, the chance of a patient having a problem at other levels is approximately 1 in 4. The benefits of the original fusion procedure are so great that most patients are willing to take this risk of degeneration.
|Dr. Mark R. McLaughlin|
Whenever one joint is fused, it is important to remember that more stress is exerted on the adjacent joints. Some studies have suggested that the incidence of arthritis is increased above and below the level of the neck fusion. Although this is probably true, it is hard to tell the cause and effect. Because people that undergo cervical fusion tend to have arthritis of the joints in the spine, who is to say what constitutes accelerated arthritis adjacent to the fusion vs. the normal progression of a patient¹s arthritis.
|Dr. Sebastian Lattuga|
Rockville Centre, NY
In general, if the spine is healthy, then a fusion does not have a significant effect on the spine. If however, there is a significant adjacent level disease, then surgery of the spine might increase the rate of degeneration of these other levels. Therefore, my recommendation is to treat all the affected levels.
|Dr. Mark Testaiuti|
A fusion causes a "stress riser" above and below the fused level and may lead to or accelerate degenerative changes in those levels anywhere from about 2 to 20 or more years later. This is a risk/benefit ratio that each patient must decide upon for himself or herself depending on how severe their problem is at time of consideration for surgery.
|Dr. Timothy C. Ryken|
Iowa City, IA
The main concern is that a fusion in one area can increase the need for motion at adjacent levels.
|Dr. Jeffrey C. Wang|
Los Angeles, CA
There are theoretical effects of a fusion which may increase the stress on the adjacent levels in the cervical spine. Long-term medical studies have shown that having a cervical fusion does not increase the chance of needing a second fusion in another area of the spine.
|Dr. Theodore A. Belanger|
The answer to this question is largely unknown. Many surgeons will tell you that a fusion can cause adjacent levels to wear out more easily, but it is unknown how many of those levels may have worn out if a fusion had not been performed. Overall, I would say that a single-level fusion probably has no significant effect on the rest of the spine, but a multi-level fusion may cause adjacent levels to degenerate more rapidly. Whether or not that means a fusion will result in a greater chance of future surgery is not at all clearly established, and opinions differ on this issue.
|Dr. Moe R. Lim|
Chapel Hill, NC
Fusions can lead to the transfer of stress to the adjacent levels. This can theoretically lead to arthritis at these adjacent levels. However, it is not known whether it is the effects of the fusion or just the natural history of degenerative cervical spine disease that causes adjacent arthritis.
|Dr. B. Theo Mellion|
There is some evidence that people who have an abnormal disc above or below the level of the fused segment can go on to develop problems. Though we are not sure what that risk is, it is fairly low. If the disc is very abnormal it is usually included in the fusion and stabilization process to prevent that from happening. But if the disc is normal above and below the fused level than the risk of having a problem at that level should not be significantly higher than it would if you had not had surgery.
|Dr. Douglas Slaughter|
Fusion in any area of the spine will cause increased stress on the levels right next to it. To that end, those levels will wear out slightly more quickly than if you did not have a fusion.
|Dr. W. Christopher Urban|
Glen Burnie, MD
Fusion surgery does not directly harm adjacent areas of the spine. It is a very focused operation that is targeted at the specific levels being fused. Great care is taken to avoid damaging the uninvolved levels of the spine. However, as the patient ages, spinal levels above or below the fusion may degenerate. Some studies indicate that this may be caused by the same factors that caused the original level to break down. Genetics, trauma, smoking or aging are all contributing factors. Other studies have shown that fusing one level puts additional stress on adjacent levels. This added mechanical stress could accelerate degeneration of adjacent levels. These levels are approached in the same manner that the original one was treated.
|Dr. Joseph Alexander|
The effect that a fusion would have on the rest of the cervical spine depends on what level of the spine is fused and how many levels are fused. Most of the nodding and turning of the head occur at the uppermost cervical levels, which are relatively rarely involved in cervical fusion operations. The most common fusions are performed in the middle of the cervical spine. By causing the bones to grow together at one or more levels, certainly some of the stress of movement of the head will be transferred to adjacent cervical spinal levels. There is a suggestion that this may cause accelerated breakdown at the adjacent spinal levels, although at this point in time, this has not been proven. Once again, however, one should not have a cervical fusion unless it is considered necessary. At that point, the risk of degeneration at adjacent segment levels may be worth taking.
|Dr. Kambiz Hannani|
Los Angeles, CA
Fusing the spine can lead to increased pressure above and below the fused area. However, newer technology is available to minimize the risk of experiencing problems in these adjacent areas. Your spine surgeon will discuss the risks of fusion versus newer technology. Disc replacement without fusion has become available recently and might be an alternative.
The commentary above recounts the experiences of these physicians. Medtronic invited them to share their stories candidly. Keep in mind that results vary; not every patient's response is the same. Talk with your doctor to learn more about any products that are mentioned above.
It is important that you discuss the potential risks, complications and benefits of spinal surgery with your doctor prior to receiving treatment, and that you rely on your doctor's judgment. Only your doctor can determine whether you are a suitable candidate for this treatment.