Cervical artificial disc replacement complications
Ross Hauser, MD.
Cervical artificial disc replacement complications
In this article, we will discuss the challenges patients may face after cervical artificial disc replacement.
We generally see three types of patients when the subject is artificial disc replacement surgery.
- We see the patients who underwent surgery with less than beneficial results, still have a lot of pain or adjacent segment problems, and are looking to avoid another or revision surgery
- We see the patients who underwent a successful surgery but still have some pain and limitations that continue to hinder them.
- We see the patients who are trying to avoid the surgery altogether.
Many people have had successful cervical artificial disc replacement surgery and are happy people. These are typically not the patients that seek our help.
- “I had two consultations for surgery.”
- Artificial Disc Replacement – Who is it best for? Who is not a candidate?
- Many people have successful surgery – here are some outcomes.
- Cervical disc replacement may not recreate the normal range of cervical spine motion. This may cause problems down the road.
- The number of people who get cervical fusion surgery when the cervical disc replacement fails.
- Repeat anterior cervical discectomy and fusion or repeat cervical artificial disc group can be performed.
- Heterotopic ossification is a common complication.
- Heterotopic ossification- the growth of bone in the tendons, muscles, and soft tissue after cervical disc replacement.
- A comparison of surgical techniques – fusion vs. disc replacement – is about motion.
- The hybrid fusion disc replacement surgery option for patients who are not good candidates for disc replacement
- How cervical surgery positively or perhaps negatively affects a patient is done via a comparison of surgical techniques.
- “The complications after total disc replacement surgery are thought to be caused by inadequate natural movement restoration.”
- Surgeons ask: “Are Controversial Issues in Cervical Total Disc Replacement Resolved or Unresolved?”
- Complications in neck surgery.
- The neck just decided to fuse itself following a disc replacement.
- Cervical spinal alignment and curvature after disc replacement surgery.
- The importance of the cervical spine curve in alleviating pain.
- Surgical treatments for cervical instability – the disc may not be the problem causing pain, loss of cervical curvature, and loss of range of motion.
- CREEP – cervical degenerative ligament disease – why neck surgery fails.
- Range of motion issues is in the ligaments.
“I had two consultations for surgery”
This is the type of story patients share with us. They tell us about cortisone injections in the neck as a last attempt to avoid surgery following many months or years of typical home remedies including stretching, yoga, and traction. Someone pushing forward with these remedies and treatments has hope that these therapies will help them avoid surgery in the near future. There is a clear desire on these people’s parts to avoid surgery and they have not reached the stage of “I am just getting the surgery and will try to be done with this.” They will also tell us about multi-segment degenerative disc disease and cervical disc bulging, maybe from C3 – C7 or C2 – C5. They tell us about the surgeon who reviewed their MRI and that doctor’s suggestion of surgery because of developing bone spurs. Then they will tell us about a second opinion they got.
- In one opinion, traditional cervical fusion with multi-level disc replacement would be suggested.
- In another opinion, from a minimally invasive cervical spine specialist, the suggestion was laser surgery to burn away the bulging areas compressing the nerves. No fusion, no disc replacement but no guarantee that this surgery would prevent the need for cervical fusion later. This may often lead people to question the benefit of laser spine surgery and go ahead with artificial disc/fusion surgery.
We will now focus on artificial cervical disc replacement.
Artificial Disc Replacement – Who is it best for? Who is not a candidate?
As a compromise between stability and motion, laminoplasty and artificial disc replacement are done with ever-increasing frequency. Laminoplasty involves cutting the lamina on both sides to make a bone flap which is propped open using small wedges or pieces of bone to enlarge the spinal canal space. Artificial disc replacements and laminoplasties have the advantage of providing some stability while preserving about 80% or so of the normal motion. Unfortunately with both, the biomechanics of the spine are still altered in the adjacent segments and there are still people who do not do well after these procedures.
In a cervical artificial disc replacement surgery, the herniated or damaged disc between the vertebrae is removed. As opposed to a fusion surgery where bone and graft are inserted into the void created by the disc removal and then the vertebrae of the cervical spine are held together with rods and screws, the artificial disc replacement surgery inserts a ball and socket joint apparatus. The idea is that this ball and joint can do the job of a natural disc by maintaining disc height and preventing the vertebrae from rubbing against each other, reducing compression on the nerves, and maintaining mobility in the cervical spine and a proper range of motion.
As a lesser procedure to bone graft, surgeons hope that they can complete the procedure within 2 hours, have the patient go home the next day, and have them return to a normal lifestyle within 2 months.
The benefits of spinal fusion in discussions between surgeons are
- Patients can move right away and do not need to wear a neck brace
- Faster recovery
- Better long-term relief than cervical spinal fusion
- Restored range-of-motion is very close to the range of motion of a healthy disc.
- Cervical disc replacement may not be the best option for people with significant spinal degeneration, multilevel herniation, loss of natural spinal curve, or people with spinal cord compression. They, according to surgeon comparisons would benefit most from spinal fusion.
It is clear from multiple scientific reviews that cervical fusions, total disc replacements, laminoplasty, and laminectomy all alter spinal biomechanics, which promotes adjacent segment degeneration. Cervical fusions and total disc replacements transfer forces to the adjacent vertebral segments increasing disc and facet pressure, which can lead to cervical instability in those segments and to long-term adjacent segment degenerative disease. Laminoplasties also are associated with adjacent segment degenerative disease. When instability or fusion is present, destructive joint forces are transferred to adjacent vertebral segments.
Surgery for Cervical Discogenic Syndrome – only as last resort?
Let’s start here with a 1995 paper (20) and bring the research currently to 2022. In 1995 the suggestion of sending people to surgery for cervical disc causing pain or cervical discogenic syndrome was somewhat controversial. In this 1995 paper Dr. Bruce S. Senter an orthopedic surgeon wrote: “In patients with persistent pain of the neck, head, shoulder, and periscapular area, the diagnosis of cervical discogenic syndrome should be considered. The intervertebral disc can be a source of persistent pain and the severity of the symptoms should dictate the treatment. Surgical intervention should only be considered as a last resort in someone with significant pain who has failed prolonged conservative therapy. The success of the surgical treatment of this entity is most closely linked to adequate patient selection and rigorous patient preparation.”
In the medical publication STAT PEARLS (21) housed at the National Center for Biotechnology Information, U.S. National Library of Medicine an update on treatment and patient selection is given with similarities in the message.
“There are many approaches to the management of cervical discogenic pain syndrome, which are dependent on the cause, severity, and clinical presentation. The initial approach is always aggressive nonsurgical treatment. This includes the use of NSAIDs, partial rest, proper posture, and body mechanics, along with home-based exercise programs. Spontaneous recovery is usually common within the first few weeks. Physical therapy should be focused on maintaining proper posture and body ergonomics. . . In some cases, patients with cervical discogenic pain syndrome may require cervical epidural injections or nerve root blocks to facilitate their participation in physical therapy. These interventions should be used as an adjunct to therapy and are not usually effective alone.
Patients who do not respond to appropriate conservative therapies and have persistent radicular pain, progressive neurologic deficits, motor weakness, or signs of cord compression may consider surgical intervention. Patients with discogenic neck pain can potentially benefit from anterior cervical discectomy and fusion surgery.”
Which surgery had a better outcome, cervical disc replacement or anterior cervical discectomy and fusion?
A March 2022 paper in the journal Clinical Spine Surgery (16) compared the clinical outcomes in patients with significant cervical spondylosis treated with cervical disc replacement compared with anterior cervical discectomy and fusion. This is what the authors wrote: “As cervical disc replacement utilization has increased over the past decade, recent studies have investigated the outcomes of cervical disc replacement in patients with more significant spondylotic changes and demonstrated improved postoperative patient-reported outcomes.” However, one question that had not been answered previously and one that should be considered important to the patients was which surgery had a better outcome, cervical disc replacement compared or anterior cervical discectomy and fusion?
The study compared patients who underwent one-level or two-level cervical disc replacement or anterior cervical discectomy and fusion with significant cervical spondylosis. A total of 66 patients were included in the present study, of which 35 (53%) were treated with cervical disc replacement and 31 (47%) with anterior cervical discectomy. At the final follow-up, there was no significant difference in the outcomes between the two groups and both groups demonstrated significant improvement.
Many people have successful surgery – here are some outcomes
A January 2021 study in the Global Spine Journal (1) examined the outcomes of 3,350 people who had elective primary Anterior Cervical Disc Arthroplasty surgery between 2008 – 2017.
- Of the 3,350 patients, 69 patients had revision surgery requiring the removal of the disc replacement.
- The most common reasons for revision surgery included cervical spondylosis or continued cervical spine degenerative disease (59.4%) and mechanical complications(27.5%).
- After removal of the disc replacement, common procedures performed included anterior cervical fusion with or without decompression(69.6%), combined anterior/posterior fusion/decompression (11.6%), and replacement of the disc replacement (7.2%).
- Patients requiring revision surgery for mechanical complications or those who underwent a combined surgical approach were at significantly higher risk for subsequent short-term complications.
But is this reflective of a successful procedure? Let’s look at more research.
Cervical disc replacement may not recreate the normal range of cervical spine motion. This may cause problems down the road.
As we will see in the research below, one of the given benefits discussed with surgical candidates for cervical disc replacement is a better range of motion in the neck compared to the traditional fusion. We will explore just how much better it is or is not in the surgical studies we are presenting here.
One of the problems that patients seek to solve with a cervical disc replacement is the abnormal motion that they are already suffering from in their neck which is causing them many challenges. They have hope that surgery will remedy this problem. For some people, this may be a false hope.
Significant posterior bone spur at C6 vertebra shortly after a C5-C6 disc replacement surgery
The caption of the below image reads Significant posterior bone spur at C6 vertebra shortly after a C5-C6 disc replacement surgery. Unfortunately for this patient, the bone spur formed because of instability after the disc replacement. This bone spur caused impingement of the anterior spinal cord and blocked CSF Cerebrospinal Fluid, causing the need for a spinal fusion.
The number of people who get cervical fusion surgery when the cervical disc replacement fails
A March 2021 paper in the journal Neurospine (18) comes from researchers at the Department of Neurosurgery, University of Campinas in Brazil and the Department of Orthopaedics, Columbia University Medical Center, The Och Spine Hospital at New York-Presbyterian. The researchers here reviewed previously published studies on the outcomes and need for revision surgeries at the index (or primary) level after cervical disc arthroplasty failure. The minimum follow-up for these studies was 5 years.
- Results: From a total of 4,087 patients, 161 patients required reoperation at the index level.
- A total of 170 surgeries were performed, as some patients required multiple surgeries.
- The most common secondary procedures were anterior cervical discectomy and fusion (ACDF) (68%, 61 patients) and posterior cervical fusion (15.5%, 14 patients), followed by other reoperation (13.3%, 12 patients). The associated outcomes for those who required revision surgery were rarely mentioned in the included literature. (The researchers noted the lack of long-term follow-up on the outcomes of the patients needing revision surgery).
The long-term revision rate at the index level of failed cervical disc arthroplasty surgery was 3.9%, with a minimum 5-year follow-up. Anterior cervical discectomy and fusion was the most commonly performed procedure to salvage a failed cervical disc arthroplasty. Some patients who required a new surgery after cervical disc arthroplasty failure may require a more extensive salvage procedure and even subsequent surgeries.
Repeat anterior cervical discectomy and fusion or repeat cervical artificial disc group can be performed
A 2021 paper (19) from surgeons at the Chang Gung Memorial Hospital at Keelung, Department of Orthopedic Surgery in Taiwan analyzed 3,957 patients who had a disc replacement surgery of which 182 underwent revision/removal of the artificial disc and 3,775 who underwent revision or removal of fusion.
- Up to 4.6% of patients in the repeat anterior cervical discectomy and fusion group had a complication, compared to 0.5% in the cervical artificial disc group.
- The 30-day readmission rate was found to be similar between the two groups (repeat-anterior cervical discectomy and fusion 3.8% vs. repeat-cervical artificial disc group, 2.2%.
- Similarly, the 30-day reoperation rate was also not found to be different between the two groups (repeat-anterior cervical discectomy and fusion, 3.9% vs. repeat-cervical artificial disc group, 2.7%).
- On multivariable analysis, removal or revision of anterior cervical discectomy and fusion was found to be only significantly associated with an increased risk of 30-day complications.
Conclusion: Repeat anterior cervical discectomy and fusion or repeat cervical artificial disc group can be performed safely and are associated with optimal 30-day outcomes, comparable to those of index procedures. However, patients undergoing revision anterior cervical discectomy and fusion may be slightly more likely to have complications than those undergoing revision cervical artificial disc group.
Heterotopic ossification is a common complication
Heterotopic ossification is abnormal bone growth that can occur weeks after surgery. The bone grows within the cervical muscles and soft tissues including the cervical spine ligaments.
A November 2021 study in the Journal of Orthopaedic Surgery and Research (2) explains the concerns of some doctors: “Heterotopic ossification is a common complication after cervical disc replacement. Biomechanical factors including endplate coverage and intervertebral disc height change may be related to Heterotopic ossification formation. However, there is a dearth of quantitative analysis for endplate coverage, intervertebral height change, and their combined effects on Heterotopic ossification.”
What the researchers are suggesting is that the artificial disc did not provide ample coverage of the cervical vertebrae endplates. This possible degenerative wear condition may be causing changes to the disc height and instability. Where there is instability, there is typically bone overgrowth.
Here is what the researchers discussed: “Patients who underwent single-level or two-level cervical disc replacement with Prestige-LP ( a specific artificial disc were retrospectively (post-surgery) reviewed.
- A total of 138 patients with 174 surgical segments were evaluated.
- Both the prosthesis-endplate depth ratio and post-operative disc height change were predictive factors for heterotopic ossification formation.
- Conclusions: “Inadequate endplate coverage and excessive change of intervertebral height are both potential risk factors for the heterotopic ossification after cervical disc replacement. Endplate coverage of less than 93.8% of intervertebral height change of more than 1.8 mm would increase the risk of heterotopic ossification. (Comment it would not take much to cause complication). The combination of these two factors may exacerbate the non-uniform distribution of stress in the bone-implant interface and promote heterotopic ossification development.”
An October 2021 paper comes to us from the Department of Neurological Surgery, Washington University School of Medicine. It was published in the journal Neurosurgery clinics of North America. (3) This paper offers suggestions on the type of patients cervical artificial disc replacement may be most successful for. Here is what the authors wrote:
- “Cervical total disc replacement has a unique set of complications compared to anterior cervical discectomy and fusion proper patient selection and astute surgical technique can minimize the complication rate. As seen in other joint replacement procedures, heterotopic ossification and osteolysis (scar tissue formation) are common in cervical artificial disc replacement. Most of the time it is not symptomatic and only needs to be observed. Revision should be considered for complications that cause symptomatology. Oftentimes, revision motion-sparing procedures (ie, revision cervical artificial disc replacement or posterior foraminotomy) can be performed, however, revision fusion may be the best option in some cases.”
Heterotopic ossification- the growth of bone in the tendons, muscles, and soft tissue after cervical disc replacement
Heterotopic ossification is the unnatural formation of bone in the tendons, muscles, and other soft tissue. Speculation in the medical community that the acquired form of heterotopic ossification can occur when a muscle is injured. Muscle is injured during surgery. Let’s look at the research:
Doctors wrote in the journal Medicine – (9)
- The occurrence of Heterotopic ossification is an inevitable postoperative complication after cervical artificial disc replacement and can decrease the range of motion at the segment where the disc was replaced. This they note is “contrary to the fundamental goal of an artificial disc.”
- Previous studies reported various results on the occurrence of Heterotopic ossification.
- One study they cite reports 17.8% of Heterotopic ossification occurrence in studied patients at 12 months of follow-up
- Another cited study reported that 78.6% of patients exhibited Heterotopic ossification at an average follow-up period of 43.4 months.
- In this study, the results of Heterotopic ossification and severe Heterotopic ossification were grouped into different subgroups, and the pooled data showed that the prevalence of Heterotopic ossification after cervical artificial disc replacement was:
- within 1 to 2 years after surgery = 38% with a condition of severe Heterotopic ossification reported in 10.9%
- within 2 to 5 years after surgery, and = 52.6 with a condition of severe Heterotopic ossification reported in 22.2%
- within 5 to 10 years after surgery = 53.6% with a condition of severe Heterotopic ossification reported in 47.5%
What causes this?
Doctors at the Spine Institute of Louisiana wrote in a June 2018 study in the International Journal of Spine Surgery (10) that it is difficult to understand why Heterotopic ossification happens.
- Heterotopic ossification is a known risk following cervical total disc replacement surgery, but the cause and effect of Heterotopic ossification are not well understood. Reported Heterotopic ossification rates vary, (as in the research documented above) and few studies are specifically designed to report Heterotopic ossification.
- The findings (of this study) are limited for clinical decision-making because we cannot yet make causal inferences (a conclusion as to cause. The researchers concluded it happens, they are not sure why it happens. Other researchers have pointed out that even if Heterotopic ossification occurs, many times it is asymptomatic and does not bother that patient at all.)
- The rates of Heterotopic ossification were shown to progress over time, warranting further research into the relationship between Heterotopic ossification and inflammatory response.
- There remains a paucity of literature analyzing potential surgical techniques and implant-specific causes of Heterotopic ossification following cervical total disc replacement surgery. Further analysis needs to be conducted to understand the significance and relationship between each of these possible predictors, and other potential predictors, such as adjacent-level degeneration, sagittal alignment, and operative levels.
- Although spine surgeons have traditionally referred to Heterotopic ossification as clinically relevant (symptomatic) and nonrelevant (asymptomatic), this nomenclature (classification) appears to be founded on Range of Motion and not impact clinical outcomes. Based on this analysis, the largest to date, it seems clear that Heterotopic ossification terminology should be more accurately defined as motion-restricting and non–motion-restricting.
We would like to point out that possible causation is adjacent-level degeneration and possible problems with the cervical neck sagittal alignment. The cervical spine’s natural alignment or curve.
What are we seeing in this image?
Below we see an image of a neck with a series of disc replacements. As we note in the image caption: Artificial joint replacement parts, in the case of this article, artificial discs, are stiff and rigid. In the supportive research noted in this image, these stiff and rigid parts are up to 500 times stronger than osteoarthritic cartilage. While the disc replacement is much stronger than the remaining natural structures, this imbalance can cause a structural breakdown in the neck. Maybe not enough to warrant a revision surgery, but a significant impact on neck pain and structure is just the same.
The imbalance of artificial components and surviving elements in the neck can cause daily joint forces to be transmitted to these weaker areas of the periarticular (the soft tissue surrounding the cervical spine) structures. This can cause the accelerated breakdown of this soft tissue and lead to neck pain and neck instability.
A September 2019 study in the journal World Neurosurgery (4) suggests that “simply understanding ranges of motion (ROMs) does not capture the quality of normal cervical motion.”
In other words, cervical disc replacement may not recreate a normal range of cervical spine motion. Remember, this comes from surgical research, it is the surgeons themselves expressing these concerns and represents the challenges some find with artificial cervical disc replacement. This research is discussed further below.
Before we go further, let’s understand again that there are many people who get a great benefit from a cervical artificial disc replacement surgery. There are a lot of people who do well with the “hybrid” surgery of anterior cervical discectomy with fusion plus cervical artificial disc replacement surgery when multiple areas of the cervical spine are causing them pain. The people who have successful surgery are, however, not typically the patients that we see in our office. But we do see a lot post-surgery:
- We see patients with new pain issues following the surgery that was supposed to resolve their old pain issues.
- We see the patient who feels that their cervical spine could be stronger and more stable following the surgery.
Generally, people who have had a successful cervical artificial disc replacement surgery will report problem situations like this:
- I feel great, the nerve pain is much less. I do have spasms in my neck and shoulders. I cannot resume my old activities yet and it is somewhat frustrating. I have been in Physical Therapy for 6 months. I may need more surgery because the other discs are now showing compression. I am looking for other options moving forward.
- I decided on hybrid surgery. I had C6/C7 fused with anterior cervical discectomy with fusion (ACDF). My surgeon recommended that to preserve a range of motion I get the artificial discs at C4 and C5. The surgery went well, I take muscle relaxants mostly, and painkillers sometimes. However, my neck does not feel strong and there is a concern that I may need more surgery.
A weakness in their ability to “hold their head up.”
The reason that these people come to our office is that they are exploring regenerative medicine treatments that may help them avoid further surgery by strengthening their cervical spine by way of addressing cervical ligament damage and weakness. We will discuss this below. They may also be in our office looking for ways to strengthen their cervical spine even after successful surgery but they feel something is not right. Some of these patients, recognize a weakness in their ability to “hold their head up.”
In this video, Ross Hauser explains how even after disc replacement surgery, cervical spine instability is not only present but has been made worse.
Again, let’s point out that many people get significant benefits from cervical disc replacement. These are the people we do not see in our office. We see the people who had disc replacement and continued or worsening problems.
A summary transcript and explanatory notes are below the video.
I’m seeing a lot more disc replacement patients with continued neck problems
- We are seeing a lot more disc replacement patients because of the popularity of the surgery. Surgeons are using disc replacement as an alternative to cervical fusion surgery.
The belief is that disc replacement can provide stability as well as a more natural motion. For some people, this did not work out.
- Some doctors believe that cervical disc replacement will be a better choice of surgery because they believe that the problem is from severe disc degeneration and what we’re finding is that, unfortunately, after they put in the disc replacement some of the time that area of the disc replacement doesn’t stabilize. What does this mean?
- When a disc replacement is performed, the surgeons have to move or stretch the cervical spine ligaments. Sometimes after the surgery, those ligaments don’t tighten back up. This is why some people who had a disc replacement come in and feel just as bad or even worse after the surgery
- Some doctors believe that cervical disc replacement will be a better choice of surgery because they believe that the problem is from severe disc degeneration and what we’re finding is that, unfortunately, after they put in the disc replacement some of the time that area of the disc replacement doesn’t stabilize. What does this mean?
At 1:10 of the video, Dr. Hauser shows on a Digital Motion X-Ray (DMX) how one patient continued to suffer from cervical spine instability
What is Dr. Hauser demonstrating with the tongue depressor?
In the video, (1:40) the patient with the disc replacement is moving their head forward. The DMX image is stopped so the cervical spine instability can be demonstrated.
- When a person moves their head forward, the cervical vertebrae should line up in an anatomically correct position. In this case, the patient’s vertebrae do not line up.
- Dr. Hauser uses the tongue depressor to show that the vertebrae do not line up in a straight line, it is a crooked line with space gaps – an unnatural distance or space between the vertebrae
DMX image of what Dr. Hauser is showing with the tongue depressor: (Note the bottom vertebrae, that is where the disc replacement is)
- The person in this DMX image did not have the disc replacement that long ago. So the cervical spine instability seen at C2 C3 C4 C5 C6 has probably been there for some time. This is why disc replacement at C6 did not help their neck problems at C2-C5
Neck pain after C5-C6 disc replacement surgery
An introductory video discussion with Ross Hauser, MD
In this video, Ross Hauser, MD, explains pain after disc replacement surgery. These are the learning points:
- The patients we see come in with cervical spine instability after cervical neck disc replacement.
- Demonstrating from a still image from a patient’s Digital Motion X-ray – a situation of offset cervical vertebrae is shown.
- In a situation of offset vertebrae, the cervical ligaments that hold the vertebrae are so loose and weak that the vertebrae float away from each other. In this video, the situation is demonstrated with problems at C5 – C6 following a disc replacement.
- The patient suffered from symptoms of clicking, grinding, and muscle tension. The muscle tension is created to help protect the spinal cord from the floating instability of C5-C6.
- The case documented in this video is very severe instability. If the patient’s muscles did not “clamp down,” on the unstable area, each time the patient looked down, the vertebrae would be pressing into the spinal cord and the nerves that pass through C5-C6.
- Prolotherapy injections which are explained below, help tighten and strengthen the spinal ligaments. In this patient’s case, 6 – 8 treatments may be required.
A comparison of surgical techniques – fusion vs. disc replacement – is about motion
If you have been recommended for a disc replacement fusion surgery, one of the main aspects of this recommendation is your need to have some type of movement in your neck and that you are a candidate for this type of surgery.
We are going to explore a June 2020 study from the Department of Neurosurgery, Medical College of Wisconsin. It was published in the Journal of the Mechanical Behavior of Biomedical Materials. (5) Let’s let the surgeons explain the differences and comparisons between anterior cervical discectomy and fusion and cervical disc arthroplasty or replacement:
“Surgical treatment for spinal disorders, such as cervical disc herniation and spondylosis, includes the removal of the intervertebral disc and replacement of biological or artificial materials. In the former case, a bone graft is used to fill the space, and this conventional procedure is termed anterior cervical discectomy and fusion. The latter surgery is termed artificial disc replacement or cervical disc arthroplasty. Surgeries are most commonly performed at one or two levels.”
Range of motion and anterior and posterior load sharing
The question that these researchers were asking in this study was to determine the external (range of motion, ROM) and internal (anterior and posterior load sharing) responses of the spines with one-level and two-level surgeries in both models (anterior cervical discectomy and fusion and cervical disc arthroplasty/replacement).
“Results for both one-level and two-level surgeries showed that anterior cervical discectomy and fusion decreases range of motion at the index level (the surgery segments or levels), while cervical disc arthroplasty/replacement increases motions compared to the intact normal spine.
The ROM, anterior column load (pressure on the front-facing part of the cervical vertebrae), and posterior column load (pressure on the rear part of the cervical vertebrae) increased at both adjacent levels for the anterior cervical discectomy and fusion while cervical disc arthroplasty/replacement showed a decrease.”
Suspected facet joint disease after surgery
“Although two-level surgeries resulted in increased these biomechanical variables, greater changes to adjacent segment biomechanics in anterior cervical discectomy and fusion may accelerate adjacent segment disease. Decreased ROM and lower load sharing in cervical disc arthroplasty/replacement may limit adjacent segment effects such as accelerated degeneration. Their increased posterior load sharing, however, may need additional attention for patients with suspected facet joint disease.”
So to recap. The benefit of cervical disc arthroplasty/replacement surgery is a better range of motion and less risk of Cervical adjacent segment disease, as compared to traditional cervical spine fusion. However, the cervical disc arthroplasty/replacement surgery may accelerate facet joint disease. Let’s again refer to the research above. “Cervical disc replacement may not recreate a normal range of cervical spine motion.” Just having more range of motion is not beneficial if it is creating a hypermobile situation that is causing the development of osteoarthritis and bone spurs.
How cervical surgery positively or perhaps negatively affects a patient is done via a comparison of surgical techniques
We are going to return now to the 2019 research we cited above and the discussion of how cervical surgery positively or perhaps negatively affects a patient via a comparison of surgical techniques. This is demonstrated in a September 2019 study in the journal World Neurosurgery (4). Here the researchers “evaluated clinical and radiologic results as well as biomechanical changes after anterior cervical discectomy and fusion, cervical disc replacement, and posterior cervical foraminotomy. (a minimally invasive surgical procedure performed from the back) and/or discectomy in individuals with unilateral single-level cervical radiculopathy.
- A total of 97 patients received surgical treatment for unilateral intolerable radiculopathy.
- Clinical outcomes included pain scores for neck and arm pain, neck disability scores, and modified Odom’s criteria (A scoring system to assess the outcome of the cervical surgery.)
- Also measured was the cervical spine range of motion for the whole cervical (C-ROM), operated segment (S-ROM), and upper and lower adjacent segment.
- A total of:
- 55 anterior cervical discectomy and fusion,
- 21 cervical disc replacements, and
- 21 posterior cervical foraminotomies were performed.
- Clinical improvement in neck disability and pain were significant after surgery; however, there was no statistical significance among groups.
- Satisfaction rate
- posterior cervical foraminotomy (76.2%)
- anterior cervical discectomy and fusion (90.9%) and
- cervical disc replacement (90.5%) without statistical difference.
- Range of motion was reported as only slightly better in the cervical disc replacements and posterior cervical foraminotomy groups, without statistical significance. Complete range of motion significantly increased in cervical disc replacement, and slightly increased in the posterior cervical foraminotomy group as compared to the results of the anterior cervical discectomy and fusion group, where the cervical range of motion decreased.
- Anterior cervical discectomy and fusion provide the lowest reoperation rate.
- Cervical disc replacement is effective in ameliorating the cervical range of motions.
- Posterior cervical foraminotomy has a greater probability of reoperation; however, the range of motion after surgery is better than with anterior cervical discectomy.
Yet within the medical community is a debate about what is considered successful cervical artificial disc replacement, when cervical artificial disc replacement should be chosen over anterior cervical discectomy with fusion, and when patients should reconsider the surgical recommendation.
If you can make the neck move more naturally, the better the chance treatment will have in achieving success.
One of the controversial issues surrounding cervical neck surgery is the movement and range of motion, or lack thereof, of the cervical spine following neck surgery. Even in artificial disc surgery, there is a question as to how much, natural movement can be restored. In the above research and research below, a key benefit is the improved range of motion with the disc replacement.
Still a question of long-term results
A January 2022 study from the Rothman Institute at Thomas Jefferson University published in the journal World Neurosurgery (17) also assessed rates of adjacent segment degeneration, adjacent segment disease, and reoperation rates as a result of adjacent segment pathology in patients who have undergone anterior cervical discectomy and fusion (ACDF) versus cervical disc arthroplasty. This study concluded that cervical disc arthroplasty results in significantly lower adjacent segment degeneration, adjacent segment disease, and reoperation rates. Although cervical disc arthroplasty may be a viable alternative to ACDF, further long-term studies are warranted to ensure consistency and establish the longevity of our findings.
The hybrid fusion disc replacement surgery option for patients who are not good candidates for disc replacement
An October 2021 study in the Global Spine Journal (18) comes from The Spine Hospital, New York-Presbyterian/Columbia University Irving Medical Center doctors. Here they write: “Although cervical disc arthroplasty has become a well-established and effective treatment for symptomatic cervical degeneration, many patients with the multilevel disease are not good candidates for cervical disc arthroplasty at all levels. For such patients, hybrid surgery-a combination of adjacent anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty-may be more appropriate.” The researchers noted that the hybrid surgery of adjacent anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty is somewhat novel and there is not much by way of patient outcomes following the procedure. In this paper questions about the short-term morbidity profile of the hybrid surgery, differences in operative duration, length of hospital stay, and readmission and reoperation rates were gathered and compared to a 2-level ACDF alone, patient group.
In this study, 390 patients undergoing hybrid surgery were followed.
- Two-level procedures were the most common (74.9%).
- Patients undergoing hybrid surgery were more likely to be younger, male, and have fewer comorbidities.
- There were no differences between hybrid surgery and 2-level ACDF in rates of any postoperative complication, transfusion, readmissions, and operative duration. However, hybrid surgery had a decreased length of hospital stay (one-half day on average), relative to a 2-level ACDF.
- Hybrid surgery patients had low rates of reoperation (1.28%).
“The complications after total disc replacement surgery are thought to be caused by inadequate natural movement restoration.”
In research from the Department of Orthopedic Surgery, Newton-Wellesley Hospital/Harvard Medical School, published in the Journal of Orthopaedic Translation, July 2019, (6) doctors wrote: “The subaxial cervical spine (C3, C4, C5, C6, C7) is the most mobile region of the cervical spine, allowing positioning of the head in a multitude of positions for various activities of daily living. As the discs degenerate, the relationship between alteration in kinematics (natural motion), resting alignment, and symptom development are not clear.”
(Explanatory note: As cervical degenerative disease occurs, it is not clear what causes the development of the person’s pain challenges or what causes one person to have symptoms of cervical spine degenerative disease, and why another person with a similar degenerative disease will have no symptoms.)
- The research continues: “Surgical treatment of disc degeneration not responding to conservative measures with anterior cervical discectomy with fusion has been the gold standard although concern remains regarding the development of adjacent segment disease. Although total disc replacement (TDR) and other motion-preserving technologies are becoming popular alternatives that are capable of restoring the cervical spine motion, recent follow-up studies indicated that symptomatic adjacent segment degeneration is not eliminated and reoperation rates of approximately 9% were reported at 24 months after surgery. The complications after total disc replacement surgery are thought to be caused by the inadequate restoration of the in vivo (within) intervertebral kinematics of the affected segments.” (Note: How the c3-c7 segment moves after surgery).
Again, what the research suggests is that:
- For some patients, symptomatic adjacent segment degeneration is not eliminated and reoperation rates of approximately 9% were reported 24 months after surgery.
- The complications after total disc replacement surgery are thought to be caused by inadequate natural movement restoration
Returning to the research:
- “Simply understanding ranges of motion (ROMs) does not capture the quality of normal cervical motion, nor does it allow appreciation for the change in the quality of motion associated with disease development and restoration of quality motion through surgical treatment.”
The researchers of this study concluded that: “the subaxial cervical intervertebral center of rotation (the place where the vertebra anchors itself to support rotation) and range of motions were segment level- and neck motion-dependent. (Each vertebra had its own unique rotation and motions and fusing or replacing one or multiple segments will impact other non-surgical treated segments). This may help to improve the artificial disc design as well as a surgical technique by which the neck functional motion is restored following the cervical arthroplasty.”
In other words, there is a concern that cervical spine disc replacement surgery does not restore the normal motion of the cervical spine in some patients and that this lack of normal motion can cause post-surgical complications and complaints. Doctors should look for ways to make the neck move more naturally. If they can, the better the chance the surgery, or any treatment will have in achieving better success.
Surgeons ask: “Are Controversial Issues in Cervical Total Disc Replacement Resolved or Unresolved?”
In the February 2018 issue of the Asian Spine Journal, (7) Neurologists in Korea published these findings in their paper: Are Controversial Issues in Cervical Total Disc Replacement Resolved or Unresolved?: A Review of Literature and Recent Updates.
Here are the summary findings and learning points:
- Since the launch of cervical total disc replacement in the early 2000s, many clinical studies have reported better outcomes of cervical total disc replacement compared to those of anterior cervical discectomy and fusion.
- However, cervical total disc replacement is still a new and innovative procedure with limited indications for clinical application in spinal surgery, particularly, for young patients presenting with soft disc herniation with radiculopathy and/or myelopathy.
- In addition, some controversial issues related to the assessment of clinical outcomes of cervical total disc replacement remain unresolved.
- These issues, including surgical outcomes, adjacent segment degeneration, heterotopic ossification, wear debris and tissue reaction, and multilevel total disc replacement and hybrid surgeries are common concerns of spine surgeons and need to be resolved. Among them, the effect of cervical total disc replacement on patient outcomes and adjacent segment disease is theoretically and clinically important; however, this issue remains disputable.
Complications in neck surgery.
It is likely that you are like many people. You want someone experienced in the challenges you are facing to help you. This would be especially true in choosing a surgeon. Many people do ask their surgeon, “how many of these surgeries have you done?” It is human nature to feel better when the surgeon reports more rather than less.
A February 2021 study published in the Surgical Neurology International (8) examined the experience of cervical spine surgery as being a factor in reduced complication rates. What the study found was the experience of the surgeon did not matter. This study is here in this article not to question the surgeon’s experience, but because it gives the most recent list of complications and rates. The complications were examined for anterior cervical discectomy without fusion, anterior cervical discectomy and fusion, and anterior cervical disc arthroplasty and noted as:
- Dysphagia (swallowing difficulties).
- Dysphonia (difficulty speaking)
- Unintended durotomy (puncture of dura matter).
- Hyposthenia (extreme neck weakness)
- Hypoesthesia (Strange sensations to the sense of touch, numbness)
- Horner’s syndrome (constriction of the pupil caused by injury to the facial nerves)
The neck just decided to fuse itself following a disc replacement
Spontaneous fusion is considered a somewhat rare phenomenon following a cervical disc replacement. But it happens. The point that we stress in our patients is that the neck is always trying to stabilize itself. One way it does this is by the formation of bone spurs. Here in this patient, a patient who had cervical disc replacement, his neck decided that the disc replacement was not providing enough stability so the neck fused over it.
Let’s take a look at a case history presented in June 2020 in the Journal of Pain Research (11) by the attending physicians of a patient whose neck decided to fuse itself.
A 63-year-old man presented to the case authors with a 6-month history of progressive neck pain and developed left C-7 radiculopathy 4 years ago. Magnetic resonance imaging revealed disc herniation at the C6–C7 levels resulting in compression of the left C-7 nerve root.
The patient underwent cervical disc replacement at the C6–C7 levels. He failed to follow up regularly as recommended postoperatively because he was completely free from the pain in his neck and left upper limb.
Four years later, he was readmitted with a 2-month history of occasional neck stiffness. Plain radiographs indicated complete radiographic fusion of the C6–C7 levels with trabecular bone bridging surrounding the cervical disc prosthesis, and dynamic imaging showed no motion.
He was seen at regular follow-up visits for up to 60 months without special treatment, as his symptoms of neck stiffness were minor and his symptom has not worsened since then.
Here again, we have a successful cervical disc replacement. The patient developed fusion and lost range of motion but had no significant pain. His body decided to just fuse itself and save him from another procedure.
In this video, Danielle R. Steilen-Matias, MMS, PA-C explains the challenges of adjacent segment disease
- We often get calls from patients who already had a cervical spine fusion or neck fusion surgery and are still suffering from the symptoms that sent them to the surgery in the first place, or, from patients for whom the cervical fusion helped initially, but the pain relief did not last and any relief was temporary.
- Some patients did not have a full understanding of what the fusion outcome will be. The segment that is fused does not move. Yet the patient still has to do their best to have normal neck movement. They have to move their head. They want to look down and look up and move their heads in a normal way.
- When you have had a neck segment fused, the segments above and below the fusion have to take on the extra stress of providing as normal neck movement as possible and they are overworked and develop adjacent segment disease, a rapid deterioration of the cervical spine.
A case presented
- A female patient came in whom I treated. She had undergone two cervical fusions into the lower cervical spine. We did a DMX or digital motion x-ray which is explained and illustrated below to look at how unstable her neck was and we could see that the segment above her fusion was unnaturally moving all over the place. She had fusion surgery 8 years ago, so this constant strain and degenerative wear and tear condition have been going on for some time. When she came in for her treatments, the symptoms she described were similar to the symptoms she had experienced 8 years prior that lead to her initial fusion surgery. A lot of neck pain, muscle tightness from muscle spasms, pain running down her arm from the vertebrae pinching on the cervical nerves.
- In her case, we determined that she would likely respond very favorably to Prolotherapy injections to stabilize the segment of her cervical spine instability.
Cervical spinal alignment and curvature after disc replacement surgery
Let’s point out again that people have good success with cervical disc replacement. In some instances, documented in the studies we will cite below, the disc replacement helped restore, in part, the natural alignment of the neck. In others, the artificial disc caused an unnatural curve and alignment in the neck that caused complications.
This is the progression of cervical neck instability. The neck has a natural “backward C” shape. Cervical instability causes a normal lordotic curve to end up as an “S” or “Snake” curve, or cervical dysstructure.
In the European Spine Journal (12), medical university researchers in Italy researchers examined alignment at the cervical spine in patients following cervical disc replacement surgery.
Here is what they wrote:
“The alignment at the cervical spine has been considered a determinant of degeneration at the adjacent disc, but this issue in cervical disc replacement surgery is poorly explored and discussed in this patient population. The aim of this systematic review is to compare anterior cervical fusion and total disc replacement in terms of preservation of the overall cervical alignment and complications.”
“In most of the retrieved studies, a tendency towards a more postoperative kyphotic alignment in total disc replacement was reported. The reported mean (average) complication rate was 12.5 % (0% in some research up to 66.2 % in other research). Complications associated with cervical prosthesis included heterotopic ossification, device migration, mechanical instability, failure, implant removal, operations, and revision.
“Even though cervical disc arthroplasty (replacement) leads to similar outcomes compared to arthrodesis (fusion) in the middle term follow-up, no evidence of the superiority of cervical total disc replacement is available up to date. We understand that the overall cervical alignment after total disc replacement tends towards the loss of lordosis, but only longer follow-up can determine its influence on the clinical results.”
The importance of the cervical spine curve in alleviating pain
- In this video, Dr. Hauser presents a case of one of our patients that came over from Europe. This case will illustrate how important the cervical curve is.
- In many patients, we see the destruction of the cervical curve is just as challenging a problem as severe cervical spine instability.
- This particular patient demonstrated symptoms following an airline flight 2 years ago.
- Symptoms included Tinnitus, feeling that her head was in a vice, nasal stuffiness, and extreme sensitivity to light.
- At 1:12 Dr. Hauser demonstrates a still image from the patient’s Digital Motion X-Ray. We see the loss of the cervical curve. This causes pressure and stretching of her spinal cord. This also alters the balance of her head on her neck and distributes the weight of the head in an unnatural manner. Further worsening symptoms. Dr. Hauser points out that the weight of the head will now stretch the cervical spine ligaments causing further cervical spine instability. The patient is in a significant degenerative condition.
- At 3:07 of the video, you can see the patient’s neck motion under DMX x-ray.
- The patient has severe cervical instability. The patient will require many Prolotherapy injections and help to correct the loss of her cervical curve.
- Prolotherapy is an injection therapy given over many sessions. Normally we see patients every 4 to 6 weeks.
Surgical treatments for Cervical Instability – the disc may not be the problem causing pain, loss of cervical curvature, and loss or range of motion
In our practice, we see many patients, not only with neck pain and radiating pain into the back, shoulders, arms, and hands but also with a myriad of symptoms related to cervical neck problems that doctors feel an artificial disc may help remedy, those related to degenerative cervical disc disease including problems of pinched nerves.
CREEP – cervical degenerative ligament disease – why neck surgery fails
Some of the most debilitating conditions attributed to problems in the neck are those due to cervical instability caused by ligament laxity. What does this mean? It means that surgery may not address the problems you are experiencing in your neck.
When spinal ligaments are exposed to continued compression or stress, they “Creep.” Creep is a medical condition that results from the deformity or elongation of the ligaments that hold the cervical spinal vertebrae in place. This is cervical spine instability.
- The surgery that cuts away the cervical vertebrae bone that is pressing on the nerves – does not correct or prevent CREEP recurrence
- The surgery that will fuse the cervical vertebrae in place so the vertebrae do not shift out of place and press on the nerves again, MAY NOT be needed at all if CREEP can be repaired and prevented by the use of non-surgical regenerative medicine techniques.
- Regenerative medicine injection techniques such as Prolotherapy explained below, work on the same understanding as fusion surgery, but with big differences.
- The regenerative injections repair the ligaments.
- The injections strengthen the ligaments’ ability to hold the vertebrae in their natural position. Which is what the fusion seeks to do.
- The big difference is that with fusion surgery you will lose a great amount of ability to turn your head from side to side and up and down. In Regenerative medicine injections the treatment repairs and allows for this natural movement of your head.
Range of motion issues are in the ligaments
A study came out of the University of Waterloo in Canada and was published in the November 2017 edition of the Spine Journal. (13) Briefly here was the problem and the goal of the study:
Loose ligaments are not normal
- Predicting the physiological (normal) range of motion (ROM) using a finite element (FE) model (a numeric scoring system) of the upper cervical spine requires the incorporation of ligament laxity.
- COMMENT: The doctors understand that ligament laxity (CREEP) is a problem of stability and instability To come up with a scoring system to define the normal range of neck motion, you need to understand how loose ligaments are not normal.
Patients suffer from big problems caused by little damage to the ligaments
- The effect of ligament laxity can be observed only on a macro level of joint motion and is lost once ligaments have been dissected and preconditioned for experimental testing.
- COMMENT: It is hard on any level to accurately determine the amount of ligament damage to the amount of instability because even small injuries or damage, sometimes undetectable, cause big problems. This is what we call cervical ligament microinstability.
Patients suffer because Ligament laxity is a mystery
- As a result, although ligament laxity values are recognized to exist, specific values are not directly available in the literature for use in finite element models.
- COMMENT: Ligament laxity is a mystery, defining it within mathematical equations for the scoring system is difficult. This is why cervical neck pain patients have a difficult time finding the right medical care. Their conditions if based on degenerative ligament disease are a mystery.
Patients suffer because cervical ligament laxity is a mystery
In this video, a demonstration of treatment is given
Prolotherapy is referred to as a regenerative injection technique (RIT) because it is based on the premise that the regenerative healing process can rebuild and repair damaged soft tissue structures. It is a simple injection treatment that addresses very complex issues.
This video jumps to 1:05 where the actual treatment begins.
This patient is having C1-C2 areas treated. Ross Hauser, MD, is giving the injections.
Treating cervical ligaments – published research from Caring Medical
In 2014 headed by Danielle R. Steilen-Matias, PA-C, our Caring Medical team published these findings in The Open Orthopaedics Journal. (14)
The capsular ligaments (the ligaments of the joint capsule) are the main stabilizing structures of the facet joints in the cervical spine and have been implicated as a major source of chronic neck pain. Such pain often reflects a state of instability in the cervical spine and is a symptom common to a number of conditions such as disc herniation, cervical spondylosis, whiplash injury, whiplash-associated disorder, post-concussion syndrome, vertebrobasilar insufficiency, and Barré-Liéou syndrome.
When the capsular ligaments are injured, they become elongated and exhibit laxity, which causes excessive movement of the cervical vertebrae.
- In the upper cervical spine (C0-C2), this can cause symptoms such as nerve irritation and vertebrobasilar insufficiency with associated vertigo, tinnitus, dizziness, facial pain, arm pain, and migraine headaches.
- In the lower cervical spine (C3-C7), this can cause muscle spasms, crepitation, and/or paresthesia in addition to chronic neck pain.
- In either case, the presence of excessive motion between two adjacent cervical vertebrae and these associated symptoms is described as cervical instability.
Therefore, we propose that in many cases of chronic neck pain, the cause may be underlying joint instability due to capsular ligament laxity. Furthermore, we contend that the use of comprehensive Prolotherapy appears to be an effective treatment for chronic neck pain and cervical instability, especially when due to ligament laxity. The technique is safe and relatively non-invasive as well as efficacious in relieving chronic neck pain and its associated symptoms.
Stabilizing the unstable neck – the case for treating ligaments with Prolotherapy
Back to our 2014 research headed by Danielle R. Steilen-Matias, PA-C, published in The Open Orthopaedics Journal. Here we outline that the problems of the cervical neck are not always problems of degenerative disc disease but problems of degenerative ligament disease. This explains why traditional treatments focused on the discs will not be successful in the long term.
The use of conventional modalities for chronic neck pain remains debatable, primarily because most treatments have had limited success. We conducted a review of the literature published up to December 2013 on the diagnostic and treatment modalities of disorders related to chronic neck pain and concluded that, despite providing temporary relief of symptoms, these treatments do not address the specific problems of healing and are not likely to offer long-term cures.
The objectives of this study are to provide an overview of chronic neck pain as it relates to cervical instability, to describe the anatomical features of the cervical spine and the impact of capsular ligament laxity, to discuss the disorders causing chronic neck pain and their current treatments, and lastly, to present Prolotherapy as a viable treatment option that heals injured ligaments, restores stability to the spine, and resolves chronic neck pain.
There are a number of treatment modalities for the management of chronic neck pain and cervical instability, including injection therapy, nerve blocks, mobilization, manipulation, alternative medicine, behavioral therapy, fusion, and pharmacologic agents such as NSAIDs and opiates. However, these treatments do not address stabilizing the cervical spine or healing ligament injuries, and thus, do not offer long-term curative options. In fact, cortisone injections are known to inhabit, rather than promote, healing.
Research on 21 patients with cervical instability and chronic neck pain
In our research published in the European Journal of Preventive Medicine we presented the following findings:
- Ninety-five percent of patients reported that Prolotherapy met their expectations in regard to pain relief and functionality. Significant reductions in pain at rest, during normal activity, and during exercise were reported.
- Eighty-six percent of patients reported overall sustained improvement, while 33 percent reported complete functional recovery.
- Thirty-one percent of patients reported complete relief of all recorded symptoms. No adverse events were reported.
We concluded that statistically significant reductions in pain and functionality, indicate the safety and viability of Prolotherapy for cervical spine instability. (15)
Summary and contact us. Can we help you? How do I know if I’m a good candidate?
Please see related articles:
- Ross Hauser, MD. Reviews of Diagnostic Imaging Technology for Cervical Spine Instability the diagnosis of cervical spine instability, and the ability to get to the root cause of the patient’s problems is still perplexing to many health care providers.
- Dynamic Structural Medicine Ross Hauser MD Review of Treatments for Cervical Spine Instability. Without normal spinal alignment and movement, neurologic structures that travel through the neck are at risk. Once alignment, curve, or stability are compromised, the body starts making compensatory changes down the spinal kinetic chain and symptoms develop.
We hope you found this article informative and that it helped answer many of the questions you may have surrounding your neck pain. Just like you, we want to make sure you are a good fit for our clinic prior to accepting your case. While our mission is to help as many people with chronic pain as we can, sadly, we cannot accept all cases. We have a multi-step process so our team can really get to know you and your case to ensure that it sounds like you are a good fit for the unique testing and treatments that we offer here.
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This article was updated April 14, 2022