FAQ Category: Cervical Spine

Both procedures are used for treatment of long term neck pain, neurological deficits, and radiculopathy stemming from the degenerative changes of the neck. Anterior cervical discectomy and fusion (ACDF), has been the gold standard for years. It involves a surgical procedure where an incision is made in the front of the neck in order to remove part of a cervical disc which lay between two vertebrae. Once the disc is removed the two vertebrae are fused together. This procedure has a very high clinical success rate for alleviating symptoms but is also associated with some negative long term side-effects including loss of cervical range of motion, increased degenerative changes at segments adjacent to the fusion level and an increased reliance on future need to solid bony fusion. A cervical disc replacement(CDR), procedure is relatively new. It involves the same approach as ACDF with an incision on the front of the neck. The disc is removed, but rather than fusing the two vertebrae, and artificial disc is implanted. This procedure also has a high clinical result in symptomatic relief, but it also helps maintain range of motion and can decrease degeneration at adjacent segments.

A group of large randomized clinical studies investigated long term outcomes comparing anterior cervical discectomy and fusion (ACDF), to cervical disc replacement (CDR). They looked at measures including perceived neck function, general health, neurologic improvement and avoidance of future secondary surgical needs. All reported improvement in all outcomes with both CDR and ACDF, with no significant difference between to two procedures. However there have been studies showing that cervical disc replacement in the long term is more effective at preserving range of motion and decreasing degeneration at adjacent segments. In 2014, a cost effectiveness review that included measuring quality-adjusted life years (QALYs)for a five year follow-up found that CDR resulted in 2.84 QALYs while ACDF generated 2.81 QALYs. The cost-effectiveness ratio using these two measures was $35,976/QALYs for cervical disc replacement and $42,618/QALYs for anterior cervical discectomy and fusion. Ultimately, CDR was found to be less costly and also more effective when compared results in a 5 year follow-up span.

This is a conversation that you first and foremost should be had with your treating physician. They will have the knowledge of what interdisciplinary care is available in your area.

Currently there are no economic studies that examine this aspect. Further studies are needed to directly compare surgical versus non-surgical techniques from a cost-effectiveness standpoint.

Only one study was found during this review, which makes it challenging to form any conclusion on which technique may be more cost-effective. Furthermore this looked at single level radiculopathy versus multi-level. Ultimately additional validation must be performed.

Yes,in a recent study printed in SPINE, March 2014, Swinkels et al. found that age does have a significant effect on active ROM of the neck.

No, in a recent study printed in SPINE, March 2014, Swinkels et al. found that gender does not have a significant influence on active ROM of the neck with age.

Problems in the neck that can cause severe pain, numbness down the arms, and sometimes even paralysis are referred to as cervical myelopathy. Cervical myelopathy can be caused by several changes that occur over time. Bone spurs along the front of the vertebrae are included in that list. Ossification (hardening) of the ligament that goes down the back of the spine (posterior longitudinal ligament or PLL) is a second potential cause of cervical myelopathy. Another is the herniation of several discs in the cervical spine (neck) with resultant spinal canal stenosis (narrowing caused by disc material pushing into the canal).

A successful treatment for this problem is laminoplasty surgery to take pressure off the spinal cord and stabilize the spine. A double-dooor laminoplasty splits the spinous process down the middle and then opens them up like french doors or two windows that open towards you. The spinous process is the bone along the back of the vertebra that you feel as a “bump” down the spine.

The effect of this procedure is to allow the spinal cord to shift backwards or “move away” from the front of the spine. The result is to take pressure off the spinal cord (called decompresson). Relief of painful (or other) symptoms with improved motion and function can be expected. This posterior approach has more advantages than disadvantages when there are protruding discs at several levels.

Likewise, this posterior laminectomy works well when there are bone spurs along the front of the vertebral bones or a stiff, tight ligament along the back of the vertebrae. With the posterior decompression, pressure is removed from the spinal cord without removing the discs, spurs, or ligaments. With this surgical approach, normal structures (ligaments, muscles) are preserved so there are fewer complications related to the operation.

You will want to ask your surgeon this question to get the clearest answer possible. But perhaps the results of a recent study will help provide some helpful information.

First of all, as you now know, problems in the neck that can cause severe pain, numbness down the arms, and sometimes even paralysis are referred to as cervical myelopathy. Cervical myelopathy can be caused by several changes that occur over time. The first is ossification (hardening) of the ligament that goes down the back of the spine (posterior longitudinal ligament or PLL). Another is the herniation of several discs in the cervical spine (neck) with resultant spinal canal stenosis (narrowing caused by disc material pushing into the canal).

A successful treatment for this problem is laminoplasty surgery to take pressure off the spinal cord and stabilize the spine. In the study we mentioned, surgeons from Korea examined the effect of doing a double-dooor laminoplasty in 58 patients diagnosed with cervical myelopathy. This type of surgery splits the spinous process down the middle and then opens them up like french doors or two windows that open toward you. The spinous process is the bone along the back of the vertebra that you feel as a “bump” down the spine.

The effect of this procedure is to allow the spinal cord to shift backwards or “move away” from the front of the spine. Many people who have cervical myelopathy have a cervical spine that is too straight referred to as kyphotic. The natural (normal) alignment of the bones in the neck is a slight backward (lordotic) curve.

With these other degenerative changes (disc herniation, ossification of the ligaments), the straighter-than-normal (kyphotic) cervical spine can put enough pressure on the spinal to cause cervical myelopathy. But not everyone has cervical kyphosis associated with symptomatic cervical myelopathy. Some patients have the more normal neck curve.

The question this group of researchers asked was whether or not this kyphotic alignment would compromise surgical results. There is less room for the spinal cord in the canal when the spine is so straight. The posterior shift made possible by the laminoplasty may place the already (posteriorly) shifted spinal cord too far back to achieve (and maintain) the positive benefit of the procedure.

They studied 58 patients with cervical myelopathy who were all treated with this double-door laminoplasty. Patients ranged in ages from 32 to 74 years old. X-rays were used to measure the amount of cervical spine curvature. The patients were divided into two groups: those with cervical lordosis (normal curvature) and those considered “nonlordotic” (abnormal curve).

Patients with 10 to 15 degrees of lordosis were in the lordotic group. Angles less than 10 degrees were nonlordotic. Anyone with more than 15 degrees of kyphosis was not included. They found that the degree of lordosis didn’t make any difference in results. In other words, preoperative cervical alignment (how straight or curved the neck was) was not a factor in how well patients maintained the benefits of the double-door laminoplasty procedure.

The authors noted that there are many different ways to perform a laminoplasty to decompress the spinal cord in the presence of cervical myelopathy. This posterior approach has more advantages than disadvantages when there are protruding discs at several levels. Likewise, this posterior laminectomy works well when there are bone spurs along the front of the vertebral bones or a stiff, tight ligament along the back of the vertebrae. With the posterior decompression, discs, spurs, and ligaments remain untouched.

Cervical nonlordosis (i.e., the presence of kyphosis or reverse cervical curve) was once considered a reason to avoid the double-door laminoplasty. The results of this study suggest preoperative alignment may not be as important as some other factors.

For now, it looks like laminoplasty can be done on patients with milder forms of cervical kyphosis. Knowing how your curve measures (i.e., how severe is the kyphosis or “straight neck”) may help explain why you may not be a candidate for this procedure.

Currently, there are three different disc replacement systems approved by the FDA and available for use in replacing diseased discs. Most surgeons are trained using one type and then they stick with that particular system in order to perfect their technique. In this way, they can also improve patient results.

The rehabilitation program after neck surgery (whether a fusion procedure is done or the alternate, the disc replacement) is not standard. You will find differences from center to center and even from surgeon to surgeon at one surgical site. The decision about whether or not to wear a soft or hard collar after surgery lies with each individual surgeon.

There are several factors that go into making this decision. The condition of your bones and surrounding soft tissues, the amount of surgery required to accomplish the disc replacement, your age, and your activity level will be reviewed. Any complications that may have occurred during the procedure will also be considered.

Most patients leave the hospital after this surgery under their own steam. They get up and walk on the same day. The surgeon is really the one to make this decision knowing what was done and the condition of your neck. You can always bring your collars with you to your preoperative visit and bring up this question at that time. But the final decision may not be made until after the procedure has been done.

There are many ways to evaluate the pros and cons (and results) when comparing cervical fusion or disc replacement for severe neck pain and instability. Change in symptoms (numbness, pain, loss of motion, loss of function) is a common source of information about what works well and what doesn’t (and therefore, which way to go).

A recent study was done that might add some helpful information for you. The surgeons chose the rate of reoperation after five years as the main means of evaluating and comparing results between disc replacement and neck fusion. The type of disc replacement system they used was the ProDisc-C.

The type of fusion procedure was the anterior cervical discectomy and fusion (ACDF). ACDF involves removal of the diseased disc with a bone-packed spacer (bone graft) placed in the space left by the missing disc. The use of hardware (plate and screws) along the front of the spine provided support and stability until healing took place.

Just over 200 patients with single-level disc disease between C3 and C7 were randomly divided into two separate treatment groups. Half (103 patients) received the disc replacement. The other half (106 patients) had the fusion procedure. As you probably know, the main difference between these two treatment types is the effect on neck motion. Fusion prevents movement at the level that was grafted together. Disc replacement allows for motion (though not usually completely full, anatomic motion).

Besides the five-year reoperation rate, they also took a look at the effect of the two procedures on the next vertebra. The incidence of adjacent segment disease (ASD) has been known to be increased after fusion compared with disc replacement. ASD refers to increased pressure in the disc spaces next to the fusion site. There can also be increased motion at those levels observed with ASD.

The concern is that fusion (or perhaps disc replacement) will increase the speed at which the next disc/vertebra starts to degenerate and break down. By comparing the five-year results in two groups of matched patients, it is possible to compare the durability of the disc replacement and the rate of adjacent segment disease with both procedures.

Although disc replacements help maintain spinal motion, they are devices that can break, shift, or sink down. Any of these problems can result in return of painful neck and/or arm symptoms and the need for a second surgery (referred to as a reoperation). Other studies have shown that the fusion procedure does have a much higher (two to six times higher) rate of reoperation compared with disc replacement.

Let’s look at what happened with these 200+ patients. Data was collected at six weeks after the surgery and again after six and 12 months. The last collection point was after five years, although the authors intend to recheck everyone seven years after the primary (first) surgery.

A dozen patients in the fusion group had at least one additional surgery (three of those 12 had more than one reoperation). There were problems with pseudoarthrosis (movement at the fusion site creating a “false joint”) and movement of the hardware (plate) lifting off the spine. This “lift-off” of the plate then caused pressure on the esophagus resulting in difficulty swallowing.

Only three of the ProDisc-C had revision surgeries. Two of those three had the disc replacement removed and the neck fused after all. None of the implanted discs broke or failed. Overall, fusion procedures had a much higher reoperation rate (five times more reoperations). The two main reasons for reoperations in either group were persistent pain and significant adjacent-segment disease (ASD).

The authors concluded that the advantages of disc replacement continue to exceed those of the fusion procedure, which has always been the “gold standard” for treatment of degenerative disc disease. In time, if motion is spared with the disc replacement and there is less adjacent segment disease and lower reoperation rates, then disc replacement may replace fusion as the “gold standard” treatment.

These results support similar findings in other studies comparing these two treatment approaches for degenerative disc disease in the cervical spine (neck). If you are still deliberating and debating in two more years, watch here for continued (the seven-year) results of this study.

If you look at the average person from the side as they look forward, the neck appears straight up and down. But, in fact, there is a backward curve called lordosis that helps keep the head and neck in perfect alignment. Injury such as you described for your grandson can change this head-neck relationship causing a condition referred to as swan neck deformity.

Ligamentous damage causing laxity looseness) can lead to instability and even dislocation of the cranium (head or C0) on the first cervical vertebra (C1). This is also known as atlantoaxial dislocation (again, referring to the abnormal movement of the head (skull) over the first cervical vertebra).

As a result of these cervical spine changes, the upper portion of the neck becomes kyphotic (develops a forward curve of the neck opposite of lordosis). The lower portion of the cervical spine then compensates by becoming hyperlordotic. The resulting changes in alignment are referred to as a swan neck deformity.

From the side view, the neck looks like the curve of a swan’s neck. These changes occur as the head, neck, body complex attempts to keep the head balanced over the neck and the eyes on a straight plane to protect vision. A similar curvature and reverse curvature of the fingers can occur in people with severe rheumatoid arthritis of the hands. Swan neck deformity of the hands is far more common than the swan neck deformity of the head and neck.

Surgery can be done to fuse the head and neck (C0-C2) and stop the abnormal movement of the atlantoaxial junction. Recently, a report was published for a series of patients (total of 68 people ages four to 68) who had this procedure under the care of one single surgeon. The goal was to see (and report on) changes in overall neck alignment with this procedure. X-rays viewing the cranium (skull) and neck and change in function and neurologic status were used to measure before and after results.

The surgery was successful for all but two patients who continued to have painful and neurologic symptoms that continued to get worse over time. In all the other patients, posterior fusion of the upper cervical spine actually resulted in the body auto-correcting the lower (subaxial) cervical spine (below the level of the fusion). This was a hoped for but uncertain favorable outcome.

The authors concluded that reversal of subaxial cervical alignment does occur in patients of all ages who have atlantoaxial dislocation that is stabilized with posterior fusion of C0 to C2. The amount of change in the lower cervical spine (C2-C7) was significantly and directly linked with the amount of change at the C0-C2 levels.

This was the first study to report on the effect of such a correction in patients with this complex swan neck deformity. The type of fusion hardware used (screw and plate system) has been approved in China but not by the United States Food and Drug Administration (FDA). This may be why you were unable to find more information about thisp problem. We hope this information helps you.

Abnormal movement of the head (skull) over the first cervical vertebra is referred to as atlantoaxial (A-A) dislocation. Ligamentous damage causing laxity (looseness), vertebral fracture, or deformity from rheumatoid arthritis can lead to this type of instability.

If you look at the average person from the side, the neck appears straight up and down. But, in fact, there is a backward curve called lordosis that helps keep the head and neck in perfect alignment. Injury, deformity, or arthritis can change this head-neck relationship causing a condition referred to as swan neck deformity.

As a result of the cervical spine changes associated with a swan neck deformity, the upper portion of the neck becomes kyphotic (develops a forward curve of the neck opposite of lordosis). The lower portion of the cervical spine then compensates by becoming hyperlordotic. These changes occur as the head, neck, body complex attempts to keep the head balanced over the neck and the eyes on a straight plane to protect vision.

Surgery to fuse the head and neck (C0-C2) is done to stop the abnormal movement of the atlantoaxial junction. Recently, a report was published for a series of patients (total of 68 people ages four to 68) who had this procedure under the care of one single surgeon. The goal was to see (and report on) changes in overall neck alignment with this procedure. X-rays viewing the cranium (skull) and neck and change in function and neurologic status were used to measure before and after results.

The surgery was successful for all but two patients who continued to have painful and neurologic symptoms that continued to get worse over time. In all the other patients, posterior fusion of the upper cervical spine actually resulted in the body auto-correcting the lower (subaxial) cervical spine (below the level of the fusion). This was a hoped for but uncertain favorable outcome.

The surgeons concluded that reversal of subaxial cervical alignment does occur in patients with atlantoaxial dislocation that is stabilized with posterior fusion of C0 to C2. The amount of change in the lower cervical spine (C2-C7) was significantly and directly linked with the amount of change at the C0-C2 levels.

This was the first study to report on the effect of such a correction in patients with this complex swan neck deformity. Auto correction and reversal of the swan neck deformity in these severe and complex cervical spine deformities may occur as a result of the body attempting to achieve global (overall) alignment or to maintain visual orientation required for upright posture. Future studies are needed to determine the exact mechanism by which the subaxial alignment of the lower cervical spine improves when the upper cervical area is surgically fused.

Neck pain and carpal tunnel syndrome may have a common cause. They could be coming from damage, injury, or compression of the same spinal nerve root. In fact, compression in one region has been shown to increase the likelihood of damage at another location along the nerve. Studies have shown that the nerves in the wrist are actually more susceptible to problems when there is compression in the neck.

Although the link between cervical spine arthritis and carpal tunnel syndrome has been proven, the exact mechanism by which this comes about remains unknown. The condition is referred to as double crush syndrome (DCS). Many experts have suggested various different ways in which this syndrome develops.

It could have to do with the damaged nerve’s ability to transport information further down. Perhaps there is a loss of blood supply. Or maybe the initial nerve damage leaves it stiff and no longer elastic enough to transmit messages along its length. Sometimes, another condition such as diabetes or thyroid disease is the missing link. But again, the exact mechanism by which carpal tunnel syndrome follows the initial neck pain remains a mystery.

Physicians have found that electrodiagnostic testing is the most valid and reliable way to document nerve impairment linked with carpal tunnel syndrome. The same type of testing is not as reliable for documenting a double crush syndrome. Commonly used tests (e.g., Phalen’s, Tinel’s) that point to carpal tunnel syndrome and are confirmed with electrodiagnostic tests cannot be used reliably to diagnose a double crush syndrome.

Sometimes the diagnosis is confirmed when treatment is/is not successful. If decompressive surgery of the neck doesn’t change the carpal tunnel symptoms but carpal tunnel release does, then the problem was located in the wrist. But choosing whether to start with treatment distally (at the wrist and hand) versus more proximally (treating the neck) is sometimes just a judgment call without firm evidence of which way is best to go.

If and when a clearer understanding of the mechanism underlying double crush syndrome is discovered, patient management can be re-visited. More appropriate and more consistently successful treatment can be developed.

One way to measure the economic value of any surgical (or medical) procedure is to calculate the cost per quality-adjusted life year (cost/QALY) gained. It sounds like this is the concept your surgeon was referring to. Proving cost-effectiveness is necessary in order to justify payment for these procedures — especially for patients on Medicare.

Here’s what cost per quality of life year (cost/QALY) really means. The actual cost of the procedure is the $15,000. But if the procedure works and you are pain free and able to return to work and/or regular daily activities, then there is a clinical benefit of the procedure each year following the surgery. That value can be measured in dollars and cents.

If there are no additional surgeries or added costs, then even a high-cost procedure like cervical spine fusion can gain even more value over time. And any surgical procedure that gains between $50,000 and $100,000 is considered “worth it” (cost-effective). You don’t actually receive that money in hard cold cash.

In a recent study, surgeons calculated the cost/QALY over a five-year period for 352 patients who had a single-level instrumented anterior cervical discectomy and fusion (ACDF) procedure. Instrumented means that hardware such as metal plates and screws were used. Bone graft material was also used to help create a solid spinal fusion.

After analyzing all the data for these 352 patients (including direct costs for additional medical procedures for complications), they found the cost/QALY gained in the first year was $106,000. That figure meets the cost-effective criteria. In the next four years, there was a continued added benefit though it wasn’t as high as the first year. For example, in the second year after the surgery, the cost/QALY gained was $54,000. In the third year, it was $38,800 and in the fourth and fifth years, it was between $24,000 (fourth year) and $29,000 (third year).

The conclusion of the study was that single-level neck fusion using the instrumented anterior cervical discectomy and fusion (ACDF) approach has lasting clinical benefit. The five-year favorable cost/QALY provides evidence that the ACDF is cost-effective and durable. In other words, the gains in health benefit are maintained over time adding value with each additional year without problems.

The average single-level cervical spine (neck) fusion costs around $15,700 so that $20,000 figure is in the ball park. With the rising costs of health care, the question does come up: is this surgery really worth that much money? One way to measure the economic value of any medical or surgical procedure is to calculate the cost per quality-adjusted life year (cost/QALY) gained. Proving cost-effectiveness is necessary in order to justify payment for these procedures — especially for patients on Medicare.

Here’s what cost per quality of life year (cost/QALY) really means. The actual cost of the procedure for your cousin was $20,000. But if the procedure works and he is pain free and able to return to work and regular daily activities, then there is a clinical benefit of the procedure each year following the surgery. That value can be measured in dollars and cents.

If there are no additional surgeries or added costs, then even a high-cost procedure like cervical spine fusion can gain even more value over time. And any surgical procedure that gains between $50,000 and $100,000 is considered “worth it” (cost-effective).

In a recent study, surgeons calculated the cost/QALY for neck fusion (ACDF) over a five-year period. There were 352 men and women between the ages of 22 and 73 years old in the study. They each had a single-level instrumented anterior cervical discectomy and fusion (ACDF) procedure. Instrumented means that hardware such as metal plates and screws were used. Bone graft material was also used to help create a solid spinal fusion.

After analyzing all the data for these 352 patients (including direct costs for additional medical procedures for complications), they found the cost/QALY gained in the first year was $106,000. That figure meets the cost-effective criteria. In the next four years, there was a continued added benefit though it wasn’t as high as the first year. For example, in the second year after the surgery, the cost/QALY gained was $54,000. In the third year, it was $38,800 and in the fourth and fifth years, it was between $24,000 (fourth year) and $29,000 (third year).

The conclusion of the study was that single-level neck fusion using the instrumented anterior cervical discectomy and fusion (ACDF) approach has lasting clinical benefit. The five-year favorable cost/QALY provided evidence that the ACDF is cost-effective and durable. In other words, the gains in health benefit are maintained over time adding value with each additional year without problems.

About 18% of the group needed follow-up care. The types of additional surgeries needed by some patients included implant removal, fusion revision, adding a posterior fusion, and removing hematomas (pocket of blood collected in the surgical area). The cost of these procedures was calculated as $20,000 per patient. But even with these added costs, the value added was greater than the additional costs, so the ACDF procedure was still considered cost-effective.

As you have discovered, patients with painful, unstable necks from degenerative disease have two surgical options when conservative (nonoperative) care fails to help. The first is still considered the gold standard (preferred choice): anterior cervical discectomy and fusion or ACDF. The second is a total disc arthroplasty or disc replacement. And as you said, disc implants have been around for about 10 years now. That means we are starting to get some study results with long-term outcomes.

In a recent report, the five-year results were provided for patients who were in a two-part study using one particular disc implant (the ProDisc-C). Spine surgeons from 13 different centers randomly placed patients with single-level painful disc degeneration into one of two groups. Group one had the anterior cervical discectomy and fusion (ACDF) and group two received the disc implant. The first report came out after two years. Now we have the five-year results.

At the end of two years, it was reported that the ProDisc-C implant was equal to cervical (neck) fusion in terms of pain relief and function. After five years, patients in both groups continued to report high levels of satisfaction. There have been no failures of the ProDisc-C implants so far.

The two significant findings showing the disc implant superior to fusion include: 1) patients with the ProDisc-C have less neck pain (less intense and less often) compared with patients in the fusion group and 2) the reoperation rate is lower among patients with the implant. All other measures (e.g., complications, failures, X-ray results of bone bridging) were equal between the two groups.

The authors conclude that the ProDisc-C implant provides just as good, if not better, results compared with the “gold standard” of spine fusion. Certainly, the disc implant group did no worse than the fusion group. And these results were fairly comparable with reports of studies investigating the two other types of implants currently on the market.

The surgeons say they expect in time that the value and benefit of disc replacement will be proven. They predict better outcomes for cervical disc replacement compared with ACDF with better motion and less chance of developing adjacent segment disease. And the risk of reoperation will remain significantly lower compared with neck fusion.

We hope this information helps when you talk with your surgeon. He or she is really the best one to advise you concerning your best option. Many patient and surgeon factors come into play when making this decision (e.g., your age, your general health, the overall condition of your spine, the condition of your bones, surgeon preference and experience).

People with painful, unstable necks from degenerative disease have two surgical options when conservative (nonoperative) care fails to help. The first is still considered the gold standard (preferred choice) : anterior cervical discectomy and fusion or ACDF. The second is a total disc arthroplasty or disc replacement.

There are several reasons why surgeons even started looking for an alternative treatment approach to replace ACDF. ACDF had been around since the 1950s. Disc implants have been around for about 10 years now, so we are starting to get some study results with long-term outcomes.

However, more than half a century of data on ACDF has shown us that despite improvements in the procedure, patients still have problems. There is measurable increased pressure on the remaining discs. Degenerative disease (called adjacent segment degeneration or ASD) on either side of the fusion site is common. Patients end up having a second surgery more often than expected.

Other problems develop after neck fusion such as stiffness, nonunion of the bone, and broken hardware (plates, screws, pins) used to aid the fusion process. Complications of the surgery can also include difficulty swallowing or speaking due to nerve damage.

In the early part of the 21st century (2002), European surgeons started using cervical arthroplasty devices. A year later, the United States Food and Drug Administration (FDA) approved the use of these implants on a trial basis. Three separate implants are now available on the market: the Bryan Cervical Disc System, the Prestige-ST Cervical Disc, and the ProDisc-C.

Studies published so far show that disc replacements (also referred to as implant devices) provide equal results to cervical (neck) fusion in terms of pain relief and function. Studies comparing these two treatment approaches providing data up to five years after surgery, show that patients in both groups continue to report high levels of satisfaction.

With either surgery (fusion or replacement), there are potential problems. Bone bridging needed to complete the fusion or to hold the disc implant in place doesn’t always happen. The absence of bone bridging across the surgical site is called nonunion. Post-operative complications and problems are still reported with either procedure. These can include difficulty swallowing, swelling, neck pain, and the need for another (second or revision) surgery.

In the case of disc implantation, the device can sink down into the bone (called subsidence). When this happens, the affected neck segment may lose motion and the patient may experience painful symptoms. Disc devices can also break or shift out of position. But when the disc replacement works well, it does maintain neck motion, which is something a fusion eliminates.

At the present time, researchers conclude by saying that disc replacements provide just as good, if not better, results compared with the “gold standard” of spine fusion. Certainly, patients with disc replacements do no worse than those with a neck fusion.

Surgeons say they expect in time that the value and benefit of disc replacement will be proven. They predict better outcomes than with neck fusion and better motion with less chance of developing adjacent segment disease. And the risk of reoperation will remain significantly lower compared with neck fusion.

Your surgeon, of course, will review all of the potential problems and complications that can occur — some from any type of surgery and others related to this specific type of procedure. Not everyone is a good candidate for this approach, so you will have to find out from your surgeon (if you haven’t already) whether or not you qualify.

The goals of a good fitting design are first to maintain the space between two vertebra (in other words maintain disc height). Preserving motion at that segment is equally important. And providing shock absorption while keeping the proper spinal alignment is important, too. The implant should be durable (last a long time) with few (hopefully no) complications or problems.

A good fit can depend on how the device sits in-between the two vertebral bones. Different shapes of implants have been tried and different methods of “fixation.” Implants can be round, square, saddle-shaped, triangular, and square with rounded edges. Some implants are serrated while others have teeth or keels to help them grab hold of the bone and stay where placed. Screws and cement have been used to aid fixation.

But the method with the best results (fewest complications, minimal debris, lowest rate of adjacent segmental disease) has yet to be determined. Studies are ongoing comparing cervical disc replacement with the standard treatment (anterior cervical discectomy and fusion or ACDF). And now with five CDR devices to choose from, research is being done to compare the results among the currently available implants.

Overall, research results show that patients who are treated with either fusion (the ACDF procedure) or cervical disc replacement (CDR) all get better. They all have less neck and arm pain and fewer neurologic symptoms (e.g., pain, numbness, or tingling down the arm).

There is always a concern for adjacent segment disease or ASD as the most likely complication. ASD is defined as degeneration of the disc at the level next to the fusion or disc implant. This seems to be improving with cervical disc replacements. These results may be explained by the fact that the implant preserves motion, so there is less pressure on the discs above and below the surgical level.

Reported complications with either procedure (disc replacement or fusion) include difficulty swallowing, vocal cord paralysis, penetration of the esophagus or dura (lining around the spinal cord), infection, and hardware failure. In the case of disc replacement, there have been rare episodes of device migration (disc implant shifts or moves significantly), spinal cord compression, and bone spur formation around the implant. Some of these problems required removal of the disc implant.

Long-term concerns include adjacent segment degeneration and wear debris from tiny flecks of metal getting into the area from the implant. There have been some questions raised about the long-term safety of disc implants from studies that showed chronic inflammation around the implant and in the spinal cord. All metal implants have an increased risk of a hypersensitivity (serious allergic) reaction.

Disc replacements were first designed for the low back (lumbar spine). Their success in restoring pain free motion led to the development of a similar device for the neck (cervical spine). Although not everyone qualifies for a cervical intervertebral disc replacement, they seem to work well for those patients who are good candidates.

In doing a literature search, we did find a recent review of cervical disc replacements (CDRs) by two surgeons at the William Beaumont Hospital in Michigan. Their intent was to bring surgeons up-to-date on the current status of these implants but much of the information they provided will be of interest to you (and other potential patients).

There are now five different models and designs to choose from. Some are made of a titanium-ceramic material. Others are a titanium-alloy outer part with a polyurethane (plastic) core. Shapes vary and include saddle-shaped, triangular, round, square, and square with rounded edges.

The goals of a good fitting design are first to maintain the space between two vertebra (in other words maintain disc height). Preserving motion at that segment is equally important. And providing shock absorption while keeping the proper spinal alignment is important, too. The implant should be durable (last a long time) with few (hopefully no) complications or problems.

A good fit can depend on how the device sits in-between the two vertebral bones. Different methods of “fixation” have been tried. Some implants are serrated while others have teeth or keels to help them grab hold of the bone and stay where placed. Screws and cement have been used to aid fixation.

But the method with the best results (fewest complications, minimal debris, lowest rate of adjacent segmental disease) has yet to be determined. Studies are ongoing comparing cervical disc replacement with the standard treatment (anterior cervical discectomy and fusion or ACDF). And now with five CDR devices to choose from, research is being done to compare the results among the currently available implants.

Overall, research results show that patients who are treated with either fusion (the ACDF procedure) or cervical disc replacement (CDR) all get better. They all have less pain and fewer neurologic symptoms (e.g., neck and arm pain, numbness, or tingling down the arm).

There is always a concern for adjacent segment disease or ASD. ASD is defined as degeneration of the disc at the level next to the fusion or disc implant. This seems to be improving with cervical disc replacements. These results may be explained by the fact that the implant preserves motion, so there is less pressure on the discs above and below the surgical level.

Other benefits of the cervical disc replacement (CDR) (over fusion) include fewer revision (second) surgeries, faster return to work, overall greater improved function, and maintenance of the improvements in pain and function over time. Longer-term studies (two years or more) tend to show fairly equal results between fusion and CDR as time goes by.

At first, cervical disc replacement was only done at one level. But now, with improved implant design and increased surgeon experience, multilevel procedures (up to three levels) are being done. Even with the increased risk of complications with multiple level implants, survivorship of the devices and patient satisfaction are high (95 per cent).

Reported complications with either procedure include difficulty swallowing, vocal cord paralysis, penetration of the esophagus or dura (lining around the spinal cord), infection, and hardware failure. In the case of disc replacement, there have been rare episodes of device migration (disc implant shifts or moves significantly), spinal cord compression, and bone spur formation around the implant. Some of these problems required removal of the disc implant.

Long-term concerns include adjacent segment degeneration and wear debris from tiny flecks of metal getting into the area from the implant. There have been some questions raised about the long-term safety of disc implants from studies that showed chronic inflammation around the implant and in the spinal cord. All metal implants have an increased risk of a hypersensitivity (serious allergic) reaction.

One final area the authors of this review article considered was the cost of cervical disc replacement (CDR) versus the fusion (anterior cervical discectomy and fusion or ACDF). At $2500 for a fusion compared with $4000 for the implant, fusion surgery is less expensive in the short-term. But if a second surgery after fusion is needed later because of increased wear and degeneration at the next segment, then in the long-run, disc replacement is less expensive.

Some insurance companies are refusing to pay for the implant surgery until the benefits of disc replacement (over fusion) are clearly proven. Long-term studies are needed to evaluate all factors related to these two very different treatment approaches to disc degeneration. In time, it may become clear which treatment will provide the most treatment benefit.