News Category: Cervical Spine

Ever since disc replacement became available for the cervical spine (neck), research has been ongoing to compare fusion surgery to disc replacement. One of the key questions has been whether or not disc replacement reduces the risk of adjacent-level disease. This study from the Spine Institute of Louisiana and Texas Spine and Joint Institute provides some additional information on this topic.

The assumption is that a fusion procedure stops motion thus increasing stress and load on the disc at the next spinal level (above or below the fusion). Disc replacement preserves motion so, in theory, should result in less adjacent-level deterioration.

Studies done so far show that patients obtain the desired pain relief with both procedures (fusion and disc replacement). The disc replacements are newer and appear to be safe and effective. Long-term studies of adjacent-level disease following disc replacement are not available just yet. Studies like this one offer short to mid-term results (two to four years follow-up).

The patient group in this study was made up of 170 adults with symptomatic cervical degenerative disc disease. Everyone in the group had failed to receive benefit needed from six months of active conservative management. They were randomly divided into the two treatment groups and followed at regular intervals over the next 32 to 54 months.

Imaging studies (MRIs, CT scans) were used to look for any evidence of degenerative changes at the nonoperated levels next to the surgical segment. They found no significant difference between the two groups in the number of patients who developed adjacent-level disc degeneration during that period of time. About 14 to 16 per cent of the 170 patients developed problems at the next spinal level.

Only a small number (four per cent) had severe enough disease to need further surgery. Most of the patients were treated conservatively without surgery. Nonoperative care included the use of antiinflammatory medications or pain relievers, physical therapy, and epidural steroid injection.

They did examine a number of other factors as potential risk factors. These included patient age, sex (male or female), smoking habits, bone density, and previous history of back problems. Only two of these factors showed any statistical significance as factors that could predict adjacent segmental disease. Those two factors were osteopenia (decreased bone density) and current history of lumbar spine degenerative disc disease.

The authors point out that it will take time for the fairly new research on artificial disc replacement to catch up with the 10 years (or more) of outcome studies on fusion for the cervical spine. Two years is not enough to predict long-term effects on adjacent spinal segments.

The results of this mid-term study indicate there isn’t a significant difference in rates of adjacent-level disease between cervical fusion and cervical disc replacement. Other factors (besides the type of surgery performed) may have a greater impact (e.g., bone mineral density and presence of disc degeneration in the lumbar spine). The authors intend to continue following this group of patients and report again later on long-term results.

In this article, a group of surgeons from China report on 120 patients who were either treated with a cervical (neck) spine fusion or disc replacement. Everyone in the study had a diagnosis of painful cervical disc disease. They were randomly placed in one of these two treatment groups. The entire group was very similar in terms of preoperative age, level treated, and symptoms (neck and/or arm pain, loss of motion, disability).

Before giving us the details of the surgeries and results, the authors offered a brief summary of what is known so far about the use of artificial disc replacements. Most of the studies have been done in the United States and Europe. This is the first study looking at the Chinese population.

Before artificial disc replacements (also called cervical disc arthroplasty) were developed, patients with chronic neck pain and instability were treated with neck fusion. The fusion stopped motion at the diseased level and thus reduced pain. But the strain on the adjacent spinal levels contributed to further disc degeneration. This is considered a negative consequence of spinal fusion procedures.

Disc replacement preserves motion without putting increased stress on the spinal segments on either side of the disc replacement. Over the years, several companies have made different types of implants. The three major disc replacement devices currently on the market include: 1) BRYAN cervical disc, 2) ProDisc-C, and 3) Bristol Disc. Two of these products (BRYAN and Bristol Disc) are made by the same company (Medtronic).

In this study, the group receiving a cervical disc implant were given the BRYAN cervical disc. The group having a fusion were treated with the Anterior Cervical Deompression and Fusion (ACDF) technique. Results were compared over a two-year period of time. Pain, motion, and disability (measured by the Neck Disability Index) were compared between the two groups. Operation time, blood loss, and length of time in the hospital were also recorded and compared.

As expected, patients with the implant had more motion than the fusion group. Levels of pain and changes in neck disability from before to after surgery were not different between the two groups. They found the surgery to put in the disc replacement took much longer than a fusion procedure. And there were some unexpected complications in the disc replacement group including excess bone formation (called heterotopic ossification) and loss of lordosis (natural neck curve).

Overall results were similar to outcomes reported in other studies making the same comparison between artificial disc replacement and neck fusion. The authors concluded that using the BRYAN disc replacement is an acceptable alternative to neck fusion for adults with painful and unstable cervical disc disease.

Although anterior cervical decompression and fusion (ACDF) is still the most common surgical procedure used in China for this condition, more and more surgeons are considering using disc replacements. More studies like this are needed to confirm the success of the artificial implants instead of the fusion procedure.

Since this was the first study in China and results so far are only short-term (two years), the authors suggested further long-term follow-up over the next 10 years. Attention should be paid to whether the spinal motion and mechanics at the level where the disc was put in is preserved and maintained. Efforts should be made to monitor adjacent levels (above and below the artificial disc) for break down (and especially faster deterioration than expected).

Trauma to the neck and/or arm can be severe enough to pull the brachial plexus right off. This injury is called a brachial plexus avulsion. In this article, a hand surgeon reports the results of 101 patients treated for brachial plexus injuries using a specific technique called the contralateral C7 nerve (CC7) transfer.

A nerve plexus is an area where nerves branch and rejoin. The brachial plexus is a group of nerves in the cervical spine (neck) from C5 to C8-T1. This includes the lower half of the cervical nerve roots and the nerve root from the first thoracic vertebra.

The brachial plexus begins with five roots that merge or join together to form three trunks. The three trunks are upper (C5-C6), middle (C7), and lower (C8-T1). Each trunk then splits in two, to form six divisions. These divisions then regroup to become three cords (posterior, lateral, and medial).

The nerves leave the spinal cord, go through the neck, under the clavicle (collar bone) and armpit, and then down the arm. The final branches result in three nerves to the skin and muscles of the arm and hand: the median, ulnar, and radial nerves.

Brachial plexus avulsion injuries don’t just cause pain and numbness in the shoulder, arm, and hand. This injury disrupts nerve messages to the shoulder, arm, and hand so the patient’s arm becomes paralyzed. Efforts to find ways to restore nerve function have resulted in the refinement of the contralateral C7 nerve transfer.

In this procedure, a portion of the C7 nerve from the uninvolved (uninjured) side of the neck was cut and used to reattach the avulsed or ruptured nerve on the other side. This can be done without causing any sensory or motor loss on the donor side.

The CC7 nerve transfer was first tried in the early 1990s with mixed results. Up to half the patients had some improvements in one study. But other surgeons reported much poorer results making them wonder if it was worth doing this procedure. The recovery time is long and the rehab required is extensive. But this author persisted in trying to improve the technique with the thought that for someone who is paralyzed, any amount of improvement is worth it.

And from the results reported in this article, it seems the patients would agree. Most of them did not regret the extensive surgery or the long recovery and rehab. And for those who were compliant (following the surgeon and therapist’s directions), results were good.

Everyone was able to get some shoulder motion back. Depending on which nerves were transferred, rate of recovery for elbow flexion was high. The most difficult recovery was finger flexion. Regaining some sensation was common but movement was more difficult to restore. If the patient had even protective sensory recovery (ability to feel hot, cold, pressure), then the procedure was still considered a “functional” success.

The patients in this study who were treated with a CC7 transfer were still considered “disabled.” But they were far more functional than they would have been if the arm and hand remained totally paralyzed. After reconstructive surgery with the nerve transfer, they could use the injured hand to hold small or light objects, assist with dressing and self care, and even hold a light brief case, bag, or purse.

Right after surgery, patients should expect to be in a neck brace for the first three weeks. Physical therapy begins after that short period of immobilization. The therapist works with the patient to help them regain motor function and control.

Electrical stimulation of the involved side and modeling active movement on the uninvolved side are key parts of the rehab program. Shoulder motions on the healthy, normal side are encouraged up to 1,000 times a day for at least three years.

Patients must be told up front what to expect, including the need for an intense, focused period of rehab lasting years. Complete independent function of the arm and hand isn’t promised but improved function is possible. It can take up to four years for some patients to regain as much sensory and/or motor recovery they are going to get.

During this time, they must remain dedicated to their exercise program. As the results of this study showed, those who stuck with it were rewarded with the best results. Once there is some nerve recovery, additional surgery including muscle transfers may be needed. The author provides detailed descriptions of the surgical procedures used for these 101 patients. He offers other surgeons his decision making process for when to use the CC7 technique.

Even with complete compliance there were some patients who had poor recovery of the hand in particular. The author suggested several reasons why this may have happened. First, the distance the nerve had to regenerate was just too great to reach all the way down to the muscles of the hand.

Second, the muscles themselves might have been damaged during the injury. Extreme, prolonged swelling or bone fracture piercing the muscles could have this effect. And finally, irreparable damage to the blood vessels might account for poor results.

The surgeon concluded by saying that this innovative surgical solution to brachial plexus injuries can restore finger sensation in a previously numb arm and partial use of the shoulder, elbow, and sometimes the hand. He goes so far as to say that the CC7 transfer may be the best option for reconstructive surgery after total brachial plexus root avulsion.

When neck pain from a whiplash injury occurs and becomes chronic is it the pain that causes disability in a direct chain of events? Or is there some other indirect factor or variable that links pain with disability? In this study, researchers from the George Institute for Global health in Sydney, Australia take a closer look at fear of movement as the possible mediating (indirect link or cause) between neck pain after whiplash injury and disability.

Fear of movement (also known as fear-avoidance behavior or FAB) is fairly common after whiplash injuries. Some people respond to pain with anxiety about their pain and fear about what it might do to them. They start to catastrophize the pain (build up negative thoughts in their minds about pain).

Before you know it, they are no longer moving freely out of fear that certain movements and actions “might” cause pain. They stop moving and start avoiding activities they previously enjoyed freely. Over time they become deconditioned and even disabled.

The group of patients (205) included in this study had all been involved in a motor vehicle accident. The accident occurred within four weeks of the study. They each reported ongoing (chronic) neck pain. They each filled out four separate surveys measuring pain, function, fear levels, and questions about physical and mental health. These test measures were completed within four weeks of the accident and again three months after the accident and one final time six months after the accident.

Special surveys just to measure fear avoidance beliefs have been developed and tested. For example, the Tampa Scale of Kinesiophobia, Pictorial Fear of Activity Scale, Fear Avoidance Beliefs Questionnaire, and Photograph Series of Daily Activities are in use by many health care professionals who work with people who have chronic low back pain.

Testing patients with post-whiplash (neck) pain using these same tools is a fairly new focus of research. It is not possible to assume that neck pain after whiplash influences (fear-avoidance) behavior and leads to disability just because this relationship has been shown for low back pain. A separate analysis is necessary, which is why this study was done.

After reviewing all the data and making comparisons, they found that fear of movement can explain about 20 to 40 per cent of pain-related disability. That means in 20 to 40 per cent of the patients, relieving pain did not reduce levels of disability.

And for the remaining 60 per cent of the patients, there is either another factor responsible (besides fear of movement) or perhaps several factors present at the same time. These other factors could be things like the presence (and severity) of other physical problems, mental health issues, or social, economic, or cultural differences.

A second observation was the fact that in this group of 205 patients, there was not an increase in pain-driven disability over time. In other words, their pain and disability didn’t get worse as time went by.

A third and final conclusion from this study was the idea that there isn’t a direct cause and effect between fear-avoidance behavior and disability. It looks more like there is a relationship of some type between pain, fear of movement, and disability but the word association is a better descriptor than cause.

What are the clinical implications of these findings? Some, but not all, patients with whiplash associated disorders can be helped by therapy to reduce fear avoidance beliefs and behaviors. Knowing which patients might fall into this category will be the subject of future studies. Other studies are also needed to find out what other factors influence the pain-leading-to-disability phenomenon.

The authors also suggest there is a need to examine the different tools used to measure catastrophizing, fear-avoidance beliefs, and fear of movement. It is possible that one of the many questionnaires in use could be more accurate and reliable than others when given to neck pain patients (compared with back pain patients).

For now, we can say there is a relationship between pain and disability in patients with whiplash associated disorders, and that in a subset of these patients, fear of movement is the key factor at play. The Fear Avoidance Model used to explain pain and disability in patients with low back pain can only explain 20 to 40 per cent of pain-related disability following whiplash injuries.

Anyone who has had an accident resulting in a whiplash injury knows the neck pain, stiffness, and loss of motion that can develop afterwards. Many people recover in a few days to a few weeks. But just as many develop chronic symptoms referred to as whiplash-associated disorder (WAD). Exercise may be a useful tool in getting past these symptoms and even preventing the transition from an acute problem to a chronic one.

In this article, a physical therapist from Australia (they call them physiotherapists there) offers us a review of the research on the topic of exercise for whiplash. Understanding the impairments in movement and problems with neuromuscular control might help physical therapists develop evidence-based exercise programs.

There are two main goals for this type of research. One is to reduce the number of people who develop chronic whiplash-associated disorders. The second is to reduce the number of repeat episodes of neck pain following a whiplash injury.

Therapists are interested in finding ways to retrain muscle coordination in patients with high levels of pain and disability. It can be a challenge to change the way muscles contract and relax when pain is the main feature preventing normal patterns of muscle activation. Movement patterns that are particularly affected by whiplash injury include the ability to move the head and neck quickly (speed) and smoothly.

Both the superficial (surface) and deeper muscles are often affected. If the problem is severe enough or goes on long enough, changes in muscle behavior and movement patterns begin to affect the nearby joints as well. Over time, the neck problem can become a throat problem (voice changes, hoarseness, difficulty swallowing) and/or an arm problem, too. Any rehab program that is successful must address all of these different components of the problem.

Some studies have shown the need to avoid treating whiplash too early. There is so much variability from one patient to the next that one treatment approach doesn’t fit everyone. Research done so far suggests it’s likely that a multidisciplinary approach is needed. Physical rehabilitation combined with psychologic and behavioral training may work best.

In summary, there are known disturbances in muscle behavior and movement of the head and neck after whiplash injuries. Efforts to study the problem may eventually help physical therapists develop specific exercise programs to prevent or address these problems.

Restoring range of motion as well as normal movement patterns may help prevent transitioning from an acute (short-term) problem to a chronic (life-long) problem. The specifics and timing of such a program remain unknown. It does look like exercise prescription will need to include joint range-of-motion, activation patterns of all muscle groups, and muscle endurance. Further research is needed in this area.

Ever have a moment when you experience a bit of dizziness? Fortunately it passes quickly and you return to normal once again. But for up to 40 per cent of people involved in car accidents, neck trauma in the form of whiplash causes persistent symptoms. Dizziness is one of three most common symptoms after whiplash trauma. Pain and postural unsteadiness are the other two common problems reported.

In this article, a physical therapist from “down under” (Australia) presents the current information available on dizziness and postural problems as these two symptoms relate to chronic whiplash. In particular, the role these two symptoms play in moving from an acute to a chronic problem is investigated.

Physical therapists often treat patients with chronic symptoms of dizziness and vestibular dysfunction (unsteadiness). Understanding the transition from acute to chronic whiplash may help therapists find better ways to treat these problems, and possibly prevent the long-term symptoms that accompany chronic whiplash.

Postural control is the ability to stay upright and move through space easily and efficiently. Head and neck alignment, vision, and balance are all components of postural control. You may not realize it but something as simple as walking across a room while carrying an object requires the complete coordination of multiple systems.

Anything (e.g., whiplash injury) that affects postural control may contribute to the development of chronic symptoms (dizziness, blurred vision, unsteadiness or loss of balance). That makes sense but what is it about a whiplash (neck) injury that can explain postural disturbances?

Sensors called receptors in the head and neck communicate with the musculoskeletal system. Together these mechanisms signal the nervous system, vestibular system, and the visual systems. The postural control that allows you to walk, see where you are going, carry objects with you, and maintain upright posture are all tied in together.

There are also reflexes between the eyes, neck, and vestibular (inner ear) system that can be altered because of damage to the cervical spine. Any change in the sensory input from the neck muscles, tendons, and joints to the postural control system can result in the common symptoms of chronic whiplash. And until the effects on the postural control system are addressed, an unending cycle occurs and the symptoms remain.

This is where physical therapy comes in. If the therapist can alter the signals to and from the cervical spine (neck), it may be possible to do more than just manage symptoms but actually put an end to them. Restoring normal sensory function in the neck and resetting the postural control system may be possible. Research so far has focused on the role of exercise, acupuncture, and manual therapy to improve postural control.

The results have been encouraging. Pain is reduced, dizziness limited, the perception of neck disability is less, and visual gaze and eye-head coordination improved. It is thought that this treatment approach improves sensitivity of the deep muscle spindle and thus improves postural control. A muscle spindle is a small cluster of specialized muscle fibers within a muscle. Also called stretch receptors, they detect stretch (changes in the length) in the muscle.

Other treatment strategies aimed at restoring normal postural control after whiplash currently under investigation include acupuncture, acupressure, vestibular rehabilitation, coordination exercises, and spinal manipulation.

Results have been variable. Some of these treatment tools improve balance and dizziness but do not alter pain. Others seem better at reducing pain but without changing coordination. Various studies combining different programs together are still underway.

In conclusion, it appears that there are multiple reasons why some people experience chronic symptoms associated with a whiplash injury. Among those reasons is the role of damage to the cervical spine as it communicates with other systems (nervous system, vestibular system, musculoskeletal system).

The effect of damage to specific receptors in the neck on postural control shows up at first as dizziness and/or unsteadiness. The role of dizziness, unsteadiness, and postural control in developing chronic whiplash syndrome is pointed out in this article.

These symptoms are not just the end result of chronic whiplash but actually part of the reason why chronic whiplash develops in the first place. The presence of dizziness early on after whiplash injury may be an indicator of (poor) prognosis. And that brings us back to the importance of finding ways to intervene early after neck injuries resulting in whiplash in order to prevent the transition from acute to chronic status.

The actual source of chronic neck pain after whiplash injuries has been a mystery for a long time. It has been difficult to sort out because there are so many possibilities within the neck structures (hemorrhage, fracture, contusion, tears). But over the last 10 years studies have started to consistently point to one area: the cervical zygapophysial joints.

A more common term for these joints is facet joints. Between each pair of vertebrae are two facet joints. These joints connect the vertebrae together in a chain but slide against one another to allow the neck to move in many directions. Except for the very top and bottom of the spinal column, each vertebra has two facet joints on each side. The ones on top connect to the vertebra above; the ones below join with the vertebra below.

Studies of humans after death called postmortem studies have really helped identify the problem areas. Animal studies and biomechanics studies have also added similar information about the possible lesions of whiplash. The agreement among all these studies called convergence has increased the validity of what were previously just theories about the physical causes of neck pain after whiplash.

The results of these studies show that tiny fractures and tears of the joint surface (called articular cartilage) and joint capsule are the main reasons for continued neck pain long after the car accident or other injury. And the key finding here is the fact that these lesions don’t show up on X-rays or MRIs. They are only seen when the neck is studied directly in postmortem analysis.

Biomechanics studies refer to research done on live humans (adults only). Volunteers willing to experience a low-speed rear impact are videotaped and X-rayed during the injury. This is how we know the sequence of events that occur within the cervical spine at the point of impact and the moments following. Correlating these cineradiography studies with postmortem examination of cadavers known to have a history of whiplash has confirmed some things.

First, compression and strain that exceeds the physiologic limits of the soft tissue structures around the facet joints has been identified. The greater the impact magnitude, the more damage is done. Low impact events seem to affect the C45 disc most often. But as the impact of the injury increases, damage extends to include C34, C56, and C67.

Tears in the anulus fibrosus (thick covering around the intervertebral discs) and tears in the joint capsules have been demonstrated. When the impact and force of injury is great enough, the anterior longitudinal ligament along the front of the cervical spine can be torn, too. Tiny meniscus cartilage in the facet joints called intraarticular meniscoids can become contused (compressed and bruised) and can even rupture.

The result of all the soft tissue damage is that the zygapophysial (facet) joints are left unprotected and can be injured as well. Animal studies have shown that stretch of the joint capsule from the injury sets off nociceptors. Nociceptors transmit messages of pain. They are located at the joints and in the muscles and tendons near the joints. Once these transmitters get started, they don’t turn off and the result can be chronic pain.

Treatment blocking the nerves to the facet joints has also added confirmation that the source of chronic post-whiplash neck pain is coming from those particular joints. Nerve blocks have become both a diagnostic test and a treatment. In other words, if the nerve block eliminates the pain, the problem is coming from the facet joint.

Radiofrequency neurotomy is another treatment that has developed out of the knowledge that blocking nerve signals to the joint can eliminate the pain. This is a neurosurgical procedure. Radiofrequency waves directed at the tiny nerve branches to the joints create enough heat to destroy the nerve endings.

The pain relief is long-lasting and works better than any other surgical or conservative approach for 70 per cent of the patients studied. And if the pain comes back, the neurotomy procedure can be repeated successfully. Ongoing relief with return to work and daily activities is reported for 60 per cent of patients who have a repeat radiofrequency neurotomy.

In summary, the certain knowledge that chronic neck pain following whiplash injuries is coming from the facet joints is helpful. Treatment directed at stopping nerve signaling pathways can provide sustained pain relief never before possible with other treatment approaches. Diagnostic nerve blocks help identify patients who might benefit from neurotomy before actually doing the procedure.

Zygapophysial (facet) joint pain is not the only cause of chronic whiplash pain. But it does account for up to half of all chronic neck pain sufferers. A 70 per cent success rate for that many patients is considered a major breakthrough in this area.

There is one drawback to this information. There aren’t specially trained neurosurgeons who can do this procedure in every community. That means the most successful treatment isn’t widely available. The answer to this dilemma isn’t clear.

It sounds simple that more neurosurgeons should train to become skilled in this technique. But even with more training, there’s no guarantee the procedures will be performed properly according to the practice guidelines already identified. And with 50 per cent of patients who have some other source of neck pain, other means of successful treatment must be determined. There is a need for additional study of this problem.

Dysphagia (difficulty swallowing) and airway obstruction can be caused by a problem known as Diffuse Idiopathic Skeletal Hyperostosis or DISH. Until now, it was believed that DISH was a rare cause of compression of the esophagus and trachea. But thanks to the efforts of researchers in the Netherlands, we have found out that this condition is on the rise around the world.

Diffuse Idiopathic Skeletal Hyperostosis (DISH) causes ligaments along the front and back of the vertebrae (spine) to turn into bone. It is also known as Forestier’s disease, after the name of the physician who recognized it. DISH more commonly affects older males.

It is usually associated with stiffness and back pain, but often it causes no signs or symptoms. When the cervical spine (neck) is affected, other symptoms may occur such as stiff neck with loss of motion, difficulty swallowing, painful swallowing, choking, and snoring.

The condition is most often confirmed by X-ray when there are at least four vertebral segments in a row ossified (hardened into bone). Other imaging tests used in the differential diagnosis include barium swallow radiography, CT scan, laryngoscopy, and MRI.

By performing a literature review called a systematic review, the authors of this article found 95 individual patient case reports and another 23 case series. A total of 204 people have been reported with this condition of difficulty swallowing, talking, and/or breathing because of the effects of DISH in the cervical spine (neck) and throat area.

The most significant finding of this systematic review is the fact that between 1980 and 2009, the number of cases reported has continued to rise. What’s behind this increase in neck and throat problems from DISH? Scientists aren’t sure yet but they do have some ideas.

First, it has been observed that adults who develop DISH are more likely to also have type 2 diabetes and be obese. Both of those conditions are abnormalities in metabolism. Since the formation of bone depends on growth factors such as insulin-like Growth Factor, it’s possible there is an underlying metabolic component to the disease. With more and more people who are obese and developing diabetes, it’s expected that the number of individuals affected by DISH will also increase in the coming years.

Second, with improved imaging technology, it’s possible that physicians are able to detect the condition more readily than in the past. This suggests that perhaps the incidence isn’t rising as much as the diagnosis is being accurately made more often. And the fact that many people have DISH and don’t know it (they have no symptoms) has kept some people from being diagnosed early on or at all.

Third, an association between heart disease and DISH may be a new discovery made by this study. By looking at these 204 cases and examining reported comorbidities (other medical problems people with DISH have), they found a higher rate of high blood pressure and coronary artery disease than previously appreciated.

The authors concluded from their study that dysphagia and airway obstruction as a result of DISH are not as rare as was once thought. The problem is not confined to one group of people or country either. Although Japanese people develop ossification of the posterior ligament of the spine more often than other groups, the case series came from around the world.

It is believed that there is a “gross underestimation” (author’s words) of the real number of cases of this problem. They further stated that the DISH condition of the cervical spine is not a “radiologic oddity” as some radiologists claim, but rather something that causes real problems. The changes observed on X-rays just are’t recognized for what they really are.

And finally, once radiologists are trained to recognize DISH when they see it, the authors believe the number of reported cases will increase even more. Physicians should get ready to see a steady increase in the number of cases of DISH. Likewise, the number of individuals with DISH affecting the neck will also increase as people live longer and develop more heart conditions, and metabolic problems such as insulin resistance, obesity, and diabetes.

Is it possible to get too much medical help too soon after a whiplash injury? That’s the question posed by the authors of this article. By examining the results of studies reporting results of early treatment for whiplash, they found a surprising amount of evidence that iatrogenic disability is possible.

Iatrogenic disability refers to the development of problems caused by the treatment. Chronic pain is one of those problems. Studies consistently showed that too much treatment too soon actually increases the risk of chronic pain and disability. How do they explain this finding? And what kind of “treatment” are they talking about?

First, let’s look at the types of treatment studied. Fitness training, chiropractic care, and physical therapy during the early stages of recovery from whiplash were linked with slower recovery. The reason? Possibly too much attention creates illness behaviors. Calling the problem a “whiplash” injury instead of a “neck strain” may be a way health care providers cause or extend the sick-role. Not enough focus on self-care may encourage passive coping behaviors.

These findings prompt the next most logical question: how should whiplash injuries be handled early on? Efforts are made to help reduce patient’s pain and improve their function towards a goal of preventing chronic whiplash-associated disorders (WADs).

There is plenty of evidence that education, home exercise, and returning to normal activities as soon as possible is the most successful approach to this problem. Reducing patients’ fear and anxiety about their condition seems to be a big help (and more successful than other hands-on treatments).

Many people wonder whether or not they should wear one of those soft neck collars after the accident. Others are quick to visit their chiropractor. The fact is a one-hour education session focused on fear reduction and staying active outperformed specialized exercises (McKenzie exercises) or wearing a collar.

And more than six visits to the chiropractor lengthened the time to recovery when compared with patients who did not see a chiropractor. Several studies did support the use of neck mobilization exercises provided by physical therapists. The exercise program was done at home by the patients.

All of these findings are the same thing the special Neck Pain Task Force has been recommending for years. Early treatment of whiplash with rest, soft collars, heat, cold, or exercise just isn’t evidence-based. Other approaches such as steroid injections, traction, and medications haven’t been studied enough to know for sure if they help or hurt recovery.

The authors say the bottom-line is that health care providers need to pay attention to the evidence and stop providing treatments that have been proven ineffective for whiplash. They say whiplash is a fairly benign problem that requires prevention management. Education, reassurance, and encouragement to get back to normal daily living is the number one effective approach to whiplash injuries.

For people with severe neck pain from disc degeneration, it is possible to have a disc replacement now instead of a neck fusion procedure. It’s a new enough treatment that surgeons are continuing to conduct studies of fusion versus disc replacement.

There is particular interest in what happens to the adjacent spinal level. In other words, does the vertebral unit above and/or below the fusion develop problems because of faster degeneration? Does using a disc replacement instead of a fusion procedure improve outcomes with less adjacent segment disease? What happens to neck motion if a fusion is reversed (removed and replace with a disc replacement)?

In this study, cadavers (human bodies preserved after death) were used. The surgeon fused some necks and compared cervical spine (neck) movement with other necks that had a one-level fusion plus a one-level disc replacement. The fusion and disc replacement were at adjacent levels.

The combination fusion-disc replacement is referred to as a hybrid. As part of the study, they did perform a fusion at one level and then reversed the procedure. This involved removing the fusion and replacing it with a disc replacement.

There were three significant findings from this study:

Imagine severe neck pain that is constant. Now add shooting pains down the arms and/or numbness down to the fingers. Now try to imagine working, dressing, answering emails, or sleeping under those conditions. That’s what patients with cervical radiculopathy experience every day.

Cervical radiculopathy refers to symptoms that come from pressure on the nerve roots as they exit the spinal column. People sometimes refer to this problem as a “pinched nerve”. Cervical radiculopathy is caused by any condition that puts pressure on the nerves where they leave the spinal column. The main causes of cervical radiculopathy include degeneration, disc herniation, and spinal instability.

Many times this problem can be treated conservatively with antiinflammatory medications and physical therapy. But when there is no relief from the symptoms after many months, then surgery is considered. Surgeons are still trying to sort out the best way to surgically treat cervical radiculopathy. There are two main choices: discectomy and fusion or disc replacement.

But the treatment options don’t end there because fusions can be done from the front of the spine (anterior approach) or from the back (posterior). With both approaches, the fusion is accomplished with bone grafts or titanium cages. And leads to another set of choices: between bone grafts from the patient (autografts) or from a donor bank (allograft).

Each of these choices has positives and negatives associated with it. Weighing the benefits against the disadvantages doesn’t always give a clear picture of how the results from each of these approaches compares. That’s where this study comes in. This is the first study to compare the results of all four choices: 1) anterior cervical discectomy and fusion (ACDF) with allograft, 2) ACDF with autograft, 3) ACDF with cages, and 4) disc replacement called arthroplasty.

The authors of the article didn’t actually treat patients with these four methods and then compare the results. Instead, they reviewed all of the published studies on these topics and analyzed the data to get a general idea of how they compared.

Results were measured based on patient outcomes of neck and arm pain, neck disability, physical and mental function, and fusion rate (based on X-rays). Neck disability was measured using a special patient survey called neck disability index (NDI). There was one other measure used to compare the groups and that was adverse events (complications or problems) during or after surgery.

There wasn’t much difference in the final results among all of these surgical treatments. It seems that no matter how it’s done, removing the disc and any bone spurs that are pressing on the spinal nerve(s) gives immediate pain relief. But just removing these tissues would leave the spinal segment unstable. That’s why the affected spinal segment is supported with fusion or disc replacement.

So the question is still: which one of these approaches to fusion or disc replacement is best? With similar results in pain relief and function, other factors must be considered. For example, autografts require the harvesting of bone from the pelvic bone.

This procedure means a longer time in the operating room under anesthesia. Many studies have shown that the donor site can become a new source of pain or discomfort. There are no such side effects with allograft. The main concern with bone from a donor bank is rejection (rare). The major downside of fusion (no matter how it’s done) is the loss of neck motion.

Disc removal and replacement with an implant restores neck motion but is a much more expensive procedure. The surgery is much more complicated and takes much longer. The high cost of the disc implant must be factored in too. And since cervical disc replacements have only been around for the last five years, we don’t have long-term studies to see how well they hold up or if there are any problems down the road.

The authors concluded that with the improvements that have been made in preparation of allografts (from the bone bank) the advantages of allograft over autograft are clear. Eliminating the donor site pain that often interferes with daily activities is a big benefit of allograft fusion. The ACDF procedure with allograft costs half that of autografts. Allograft safety record is well-documented making this an excellent choice for anterior discectomy and fusion.

You may have heard the statistic that 80 per cent of all adults will experience back pain sometime in their life. Would it surprise you to know neck pain affects up to half of all adults? In both cases (back and neck pain), the condition is referred to as mechanical pain.

Mechanical back or neck pain describes pain that usually occurs with movement and is not caused by fracture, inflammation, tumors, nerve problems, or other known systemic causes. Most of the time the underlying cause remains unknown. Whether it’s a ligamentous problem, muscle tension, an issue with spinal alignment, or some other factor, no one knows for sure.

Even when we don’t know what is causing the neck pain, treatment can still be effective. The usual treatment goals are to reduce pain and increase neck motion. The natural result of achieving both these outcomes is improved function.

So the question naturally arises, what treatment works best? That’s the rub — we don’t know yet. Neck pain is one condition for which there is no gold standard treatment. Gold standard treatment refers to the best known treatment with best results based on evidence from clinical research.

But all is not lost! Research is ongoing to compare current treatments against each other. In a recent systematic review, the results of thoracic spine thrust manipulation was compared to some other type of treatment. Neck pain and neck motion were used in all studies to measure the outcomes.

Thoracic spine thrust manipulation refers to a hands-on treatment of the mid-back (thoracic spine). A physical therapist or chiropractor places the patient’s body in a specific position and then applies a force through the joint. This type of thrust manipulation helps realign the spinal joints, takes pressure off the discs, and allows the nearby muscles to relax.

When researchers conduct a systematic review, it means they look at all the studies already published on a single topic, condition, or treatment. They choose the studies with the highest quality that are consistent with one another and then combine all the results.

In the case of this topic, there were six studies that met the test for high-quality. A total of 173 patients were included. The thoracic spine manipulations were all done by physical therapists trained in this type of manipulative treatment referred to as manual therapy.

After examining all of the data, it seems that thrust manipulation of the midback can help improve the neck. The benefits of manipulating the upper-mid back to reduce neck pain were observed right away but the results may not last. The studies only followed patients for six months, so there isn’t a long-term effect reported.

The studies contained in this systematic review did not compare the results of manipulation against multiple treatment techniques (exercise, manipulation, neck brace, stretching and so forth). It is possible that patients would get better faster and stay well longer if treatment consisted of two or more treatment techniques combined together.

It is also possible that there is one type of thrust manipulation (i.e., specific technique) that works better than another. In addition, the differences in treatment outcomes may be based on the location of the problem within the spine. Perhaps the position the patient is in (sitting, lying down) when the manipulation is done makes a difference.

The authors of this systematic literature review on thoracic manipulation to treat neck pain say the results can’t be applied to everyone. There are too many missing variables and different factors to take into consideration. Further investigation is recommended.

It makes sense that patients having anterior cervical spine surgery (from the front of the neck) might experience difficulty swallowing for a few weeks after the procedure. This symptom of painful swallowing is called dysphagia. But how come some patients develop this transient (temporary) symptom and others don’t? And how often does it happen?

These are the questions posed in this study by surgeons from the University of Pittsburgh. They compared a small number of patients who had an anterior cervical discectomy and fusion (ACDF) with a similar-sized group of patients who had a lumbar spine (low back) fusion.

ACDF refers to the surgical removal of a damaged disc from between two vertebrae with fusion of those two vertebrae to each other using bone grafts, titanium cages, or other similar fixation devices. The word anterior in the name tells us the surgeon made the incision and performed the procedure from the front of the spine.

The lumbar procedure was done from the back or posterior aspect of the spine. For some patients it was just a matter of removing the damaged disc while others had a disc removal and fusion. They used lumbar spine patients as the comparison group to see if the swallowing difficulty is a leftover effect of intubation (breathing tube placed down the throat during anesthesia).

Post-operative dysphagia seems to be a fairly common problem. As many as 60 per cent of all patients having the anterior cervical discectomy and fusion (ACDF) procedure report this as an annoying and sometimes disabling symptom. Although the dysphagia usually goes away in the first three weeks after ACDF, there are cases of chronic (permanent) dysphagia.

A special questionnaire called the Swallowing-Quality of Life Questionnaire (SWAL-QOL) was used to measure dysphagia. This survey helps determine the type of symptoms, frequency of symptoms, and effect of dysphagia on the patient’s life.

Patients ranked the presence of symptoms such as coughing, choking when eating, gagging, drooling, and problems chewing from never present to almost always present. Other symptoms on the survey include food sticking in the throat or mouth, food or liquid dribbling out of the mouth, and having excess saliva or phlegm in the throat.

They found that the anterior cervical discectomy and fusion group were much more likely to experience dysphagia after surgery than the lumbar surgical group. When all the data was analyzed, it wasn’t the patient’s age, length of surgery (intubation), history of diabetes or rheumatoid arthritis or even body size that put patients at risk of dysphagia. This symptom was more likely to develop in women and in patients who had a history of smoking and especially those who had a history of chronic obstructive pulmonary disease (COPD).

The authors concluded that post-operative dysphagia is related to the anterior cervical spine surgery and not the intubation process. Although they did not assess specific causes of the dysphagia, other researchers have commented on this problem. For example, it has been suggested that moving the esophagus to one side during the anterior neck surgery may be a factor in the development of dysphagia.

It’s possible that bone spurs present even before the cervical spine surgical procedure is done may contribute to the problem after surgery. Other studies have pointed to older age as a possible risk factor for dysphagia after cervical discectomy and fusion but not all study results agree on this one. Vertebral fusion at more than one level may also be a risk factor for dysphagia.

In summary, it appears from this study that difficulty swallowing after spinal surgery is an effect associated with anterior cervical spine (neck) surgery much more often than with lumbar (low back) spine surgery. Although having a tube down the throat may aggravate the problem, it’s not the primary (main) problem. At least for this group of patients, the effects didn’t last past three months. Everyone was able to recover without permanent or disabling dysphagia.

Anyone with chronic neck and shoulder pain following a car accident may be diagnosed as having fibromyalgia when in fact, they are simply experiencing long-term symptoms of whiplash. How can we tell the difference?

Fibromyalgia, a common painful disorder among women in their middle years (40 to 60 years old) is no longer considered a “disease” but rather a syndrome. The term syndrome is used to represent a group of symptoms that tend to occur together either at the same time or in close proximity to one another. Sometimes fibromyalgia is referred to as fibromyalgia syndrome (FMS).

The most common symptom is widespread pain throughout the body, with especially tender spots near certain joints. The pain stops people with fibromyalgia from functioning normally, partly because they feel exhausted most of the time.

Fibromyalgia is a chronic (meaning long-lasting) condition that usually requires many years of treatment. It can occur along with other forms of arthritis or all by itself. It can occur after an injury or out of the blue.

The history of an injury like a car accident is where the long-term effects of whiplash (called whiplash associated disorder or WAD) can get confused with fibromyalgia. With both conditions, there are tender points (TPs) in the neck and shoulder region.

According to a recent study, using tender points as the test in people who have chronic pain after a motor vehicle accident will often yield a diagnosis of fibromyalgia. Yet when retested six months later, the symptoms are gone for many people. The majority no longer have fibromyalgia.

What’s wrong with this picture? As we mentioned, fibromyalgia is usually a long-lasting problem that doesn’t just go away six months later — not even after treatment. And it is characterized by tender points all over the body, not just in the neck and shoulder areas. As a general rule, people with whiplash associated disorder tend to have local tender points (i.e., just in the neck and shoulder and not anywhere else).

The research was conducted at the University of Washington in Seattle. The authors examined over 300 patients with continued neck and shoulder pain more than three months after a motor vehicle accident.

They tested everyone using two sets of tests: one was the standard, full test for fibromyalgia developed by the American College of Rheumatology (ACR). The second was a modified test leaving out the tender points in the neck and shoulder areas.

As it turns out, there was an inflated number of patients diagnosed with fibromyalgia when the neck and shoulder points were included. The results of this study support findings from some other studies but there is still some disagreement in results from study-to-study.

For example, one study compared the number of patients with what looked like fibromyalgia after injuries of the neck versus injuries (fractures) of the leg. The patients with neck injuries were 13 times more likely to have fibromyalgia than the group with leg fractures.

In another study, it was discovered that the patients with whiplash who also developed fibromyalgia didn’t really have widespread pain (a hallmark finding with fibromyalgia) on a consistent basis. When tested every month for a year, it became clear that the symptoms were transient (came and went) after a car accident.

What is the general trend here? Just because patients with whiplash associated disorder continue to have neck and shoulder pain doesn’t mean: a) now they have fibromyalgia or b) the symptoms of fibromyalgia are permanent.

In this particular study, patients were treated after their neck injuries with a combination of behavioral therapy and physical therapy. The behavioral therapy was to help keep them moving and not allow fear of reinjury to get in the way of recovery.

The results were compared to patients with fibromyalgia treated in a similar fashion. This comparison was to make sure the difference in results wasn’t because of the fact that the whiplash group had this type of treatment. But again, the whiplash group did not end up with permanent symptoms of fibromyalgia so it wasn’t the treatment that made the difference.

It should not be assumed that patients suffering from chronic whiplash associated disorder (WAD) have fibromyalgia syndrome (FMS) — even when they test positive for it.

Most patients with chronic neck and/or shoulder pain following a whiplash injury don’t have widespread tender points. If they do, these points are not consistently tender when tested over time. The fluctuating symptoms are an indicator that fibromyalgia is not the underlying problem.

Surgeons are actively studying the advantages and disadvantages of neck fusion compared with disc replacement. In this study, they take a closer look at the amount of ossification of the surrounding ligaments in two groups of patients after surgery. Ossification refers to the formation of bone within soft tissue structures such as muscles and ligaments.

The exact cause of ossification isn’t quite clear. It could be part of the healing response of the soft tissues after being cut and moved away from the bones. There is some thought that the pins used in the procedure might generate this type of response. Not everyone develops ossification. When they do, there aren’t always any symptoms (such as pain) or obvious effects (further loss of motion). So just how much of a problem this problem is remains under investigation.

In this study comparing the amount of ossification between neck fusion and disc replacement, each patient had the selected procedure at one level in the cervical spine (neck). Everyone had tried conservative care first before resorting to surgery. The first group had an anterior cervical discectomy and fusion (ACDF). In this procedure, the surgeon comes in from the front of the neck (anterior) and removes the disc (discectomy). Then the two vertebrae (one above the disc and one below the disc) are held together (fused) with a metal plate and screws (also called pins). Only one level (between C3 and C7) of the cervical spine was operated on.

The second group had a disc replacement with a particular disc replacement product (the Bryan disc) made by the Medtronic Company in Memphis, Tennessee. As with the fusion procedure, only one cervical level was replaced in the disc replacement group. For both groups, X-rays were taken two years after the initial surgery. X-rays were repeated four years after the procedures. The location and amount of ossification were recorded. No one had any signs of ossification before the surgeries and no effort was made to prevent ossification after surgery.

As it turns out, patients in both groups developed some ossification. But the fusion group had significantly more ossification when compared with the implant (artificial disc) group. Here are a few statistical details to give you an idea of the differences between the two groups. At the end of two years, 64 per cent of the fusion group had ossification of the anterior longitudinal ligament at the levels adjacent (above and below) the fusion segment. By comparison, only 25 per cent of the artificial disc group developed ossification at the two-year check-up point.

At the end of the study (four years after the surgery), 84 per cent of the fusion group showed signs of ossification. This compared with 52 per cent in the disc replacement group. In both groups, there were patients who didn’t develop any ossification at all. That finding (and those patients) is the focus of future research. If scientists can identify why some patients don’t develop this problem at all, it might be possible to prevent it in everyone.

Scientists have thought that perhaps the closeness of the metal plate to the next disc space might be a cause of the ossification. There was one previous study where it looked like placement of the metal plate less than five millimeters away from the disc resulted in more cases of ossification. But the results of this new study did not support that finding. The authors of this study are still thinking it’s more likely that preserving motion with a disc replacement is the key factor in preventing (and possibly delaying) ossification.

One other aspect that remains a mystery is the fact that if patients don’t develop adjacent-level ossification 12 to 24 months after a disc replacement, then they aren’t likely to develop it later. Other causative factors being considered include whether it’s the plates that stimulate the ossification, the pins holding the plates in place, neither, or both. Alternately, it could be just a matter of changing the biomechanics of the cervical spine that is really the start of the ossification process.

For now, this study doesn’t answer the question of why ossification develops. But it is an important study because it’s the first time anyone has looked at the Bryan implant and compared it to anterior cervical discectomy and fusion (ACDF) in relation to ossification. There’s plenty of room for follow-up studies to identify cause and effect in an effort to prevent ossification after fusion and/or after disc replacement. For now we can say there is much more ossification with cervical fusion compared with the Bryan disc replacement.

Twenty-five patients treated with the new Discover disc replacement for the cervical spine (neck) provide some early results from this study. The implant (manufactured by DePuy) is made of titanium with a polyethylene (plastic) insert to mimic the natural disc. It is designed to restore full motion and even incorporates the lordotic angle (curvature) of the natural spine.

The patients could have had the more traditional procedure called anterior cervical discectomy and fusion (ACDF). With ACDF, the surgeon removes the degenerative disc and fuses the two vertebral bones on either side of the disc together. Patients in this study were offered either the ACDF or disc replacement (called cervical arthroplasty).

They chose the arthroplasty. After the disc was removed, the ends of the vertebral bodies (called endplates) were smoothed down. The Discover implant was inserted into the empty disc space and positioned properly using fluoroscopy (special three-dimensional, real-time X-ray).

The surgeon was careful to choose the correct size of implant for each patient and to maintain the proper disc height. Special “teeth” built in to the implant help hold it in place until bone fills in around it. There is no need for a bone graft.

Each patient had a disc herniation with pressure on the spinal cord or spinal nerve roots. Conservative (nonoperative) care was unsuccessful in changing their symptoms. They went into the surgery knowing that if disc replacement was not possible, the surgeon would do a fusion procedure instead.

Results were assessed 12 to 18 months later using a variety of different measures. For example, before and after X-rays were compared. Pain levels, neck range-of-motion, and function were evaluated. Special tests used included the Neck Disability Index, the Japanese Orthopedic Association (JOA) scale, and Odom’s Scale.

Pain relief was good-to-excellent. Motion was improved and both measures (pain relief and motion) stayed improved throughout the follow-up period. The implants remained in good position with no evidence of subsidence (sinking down into the bone).

Careful preparation of the endplates helps ensure good spinal alignment. Good contact between the implant “teeth” and the vertebral bone holds the implant in place. This placement is important to keep it from sliding too far back where it could put pressure on the spinal cord.

There were no major complications such as death. Adjacent degenerative disease (break down at the level above or below the implant) was not observed. This was the first study published with results from the new Discover artificial disc replacement device. The study was small and reported early results but the outcomes were encouraging.

The editors of the journal in which this article was published made a few concluding comments. They point out that this was a small study with many limitations. More studies of higher quality are needed before the Discover implant can be deemed safe and effective. Studies comparing results between the Discover arthroplasty and the anterior cervical discectomy and fusion (ACDF) procedure will be important as well.

If you are any kind of football fan, you’ve probably heard the term stinger. Simply put, a stinger is an injury to a nerve in the neck. It’s a common injury among players involved in contact sports. Getting hit on the head from one side is usually enough to do it. A cervical nerve (coming from the spinal cord to the arm in the neck) gets stretched or pinched.

Burning pain down the arm after getting hit is the main symptom. There may be additional symptoms of arm weakness and numbness. The symptoms are usually transient (temporary) and go away within 24-hours. But repeated stingers over time can eventually lead to a chronic stinger syndrome. With a chronic stinger, symptoms of neck and shoulder pain with numbness, tingling, and weakness don’t go away.

Having a means of predicting who might develop a chronic stinger syndrome would be helpful. With this information, athletes could be advised on the risks associated with repeated stingers. This is important because many athletes who suffer from one stinger will have more than one. And given the fact that up to 65 per cent of all football players get at least one stinger, the number of players affected is pretty high.

Imaging studies are used to help predict who might develop a chronic stinger syndrome. In the past, a ratio called the Torg ratio was used. This is a way of using X-rays to assess the diameter of the opening for the spinal cord and spinal nerve(s). Narrowing of the spinal canal (where the spinal cord is located) causes a condition called stenosis. It’s the stenosis that puts pressure on the cord or nerves causing symptoms.

It turns out that the Torg ratio is highly sensitive (it accurately tells who has the problem). But it has a poor positive predictive value, which means it doesn’t predict who (with stenosis) will develop actual neurologic symptoms. The Torg ratio doesn’t account for the effect of the surrounding soft tissues. In using statistical measurements like this, positive predictive values are more clinically meaningful than sensitivity.

So, surgeons have turned to the mean subaxial cervical space available for the cord (MSCSAC) index to predict chronic stinger syndrome. This is a measurement made using MRIs that looks at the diameter of the spinal cord in comparison to the diameter of the spinal canal. It gives a much more accurate picture of what’s going on and who might develop a chronic stinger syndrome.

Most players who do experience persistent symptoms from a chronic stinger recover. With conservative care, they are able to return to 100 per cent participation in their sport. Anyone suffering an acute stinger should be advised to rest and avoid contact sports (anything that could cause traction, compression, or direct blow to the head/neck).

Some players use a special collar called a cowboy collar to protect the neck. This is worn during play and practice. Some players use a special collar called a Cowboy Collar to protect the neck. This is worn during play and practice. It is a cervical collar (fits around the neck) underneath the shoulder pads. The Cowboy Collar fills the gap between the helmet and the shoulder pads. When worn with regular shoulder pads, the Cowboy Collar helps absorb shock.

Special exercises to help stabilize the head and neck are encouraged. Players should be told that multiple stingers and chronic stinger syndrome are linked with degenerative changes in the spine that can cause problems much later in life.

The use of cervical artificial disc replacements (CADR) is still in the first decade (10 years) of study. Before conducting studies on humans, computer simulation can be used to assess the biomechanical effects on movement. This concept is referred to as kinematics.

Computer Aided Design (referred to as CAD models) is widely used for many areas of study from theatre lighting to engineering bridges and now surgical procedures like the cervical artificial disc replacement (CADR).

In this study, mathematicians joined mechanical engineers and orthopedic surgeons to compare different types of cervical disc implants using a computer aided design model. They used the CT scans of a young, healthy 21-year-old man to build the spinal model. With a computer-aided model, everything is done in three-dimensions. The effect of force and load with motion is calculated by the computer rather than on a live subject.

Two different types of artificial disc implants were compared. Both were made of cobalt-crome with a polypropylene (plastic) core (inner piece). The artificial device mimicked the natural anatomy of a disc with its outer layer (annulus fibrosus) and the inner core (nucleus propulsus). Placement was at the C56 level where the majority of disc implants are currently placed.

The first implant was a fixed-core type. This means the inner piece did not move, shift, slide, or glide intentionally. The second implant type was a mobile core unit meaning the inner plastic core could move above the lower plate that formed the bottom half of the device.

All material and mechanical properties of the implanted device were programmed into the computer aided design model. Likewise, force, load, friction, tension, and angles were included in the model. In this way, the model could be put through thousands of spinal movements normally available in the human body and the results could be studied without subjecting a live human to that kind of experimentation.

Range-of-motion and load placed on the facet (spinal) joints were measured. The effects of load on spinal flexion-extension were evaluated. Data was also collected on the effects of side-bending load, rotational (twisting) load, force on the spinal (facet) joints, and stress on the spinal ligaments. Tension on the polyethylene core was also measured.

In general, range-of-motion increases are observed with all types of artificial disc implants. The reason for this is the fact that the anterior longitudinal ligament (down the front of the spine) is cut away in order to remove the disc. In this study, they found that range-of-motion was greater in all directions with the more mobile disc implant. There was more load and force on the spinal joints at the level of disc replacement (but not above or below that level).

Stress applied to the six spinal ligaments was tested and compared with and without the implant. There were significant increases in tension on the posterior longitudinal ligament (PLL), posterior capsule, and ligamentum flavum during flexion (forward bending motion) of the spine. These are soft tissue structures along the back of the spine. There was no significant change in the motion of segments above or below the artificial level.

In summary, the use of this newly developed model (computer-aided design (CAD) for the cervical artificial disc) provides a biomechanical comparison between two different types of implants.

That’s helpful because comparing prostheses with fixed versus mobile core structures is a little bit like comparing apples to oranges. The differences in design create a slightly different center point for the implant. These mechanical differences could affect load and pressure both on the implant as well as on the facet (spinal) joints.

And as it turned out, the fixed core with its smaller motion and lower pressure on the joints and ligaments did put more pressure on the core itself. On the other hand, with less pressure on the mobile core, it may hold up better while still providing good motion. Long-term human studies will be needed to know for sure.

When you think of someone with severe inflammatory rheumatoid arthritis (RA) what picture comes to mind? Knobby, gnarled hands is the first thought that many people associate with RA. Although RA seems to target the small joints of the hands and feet, in fact, it can affect any joint in the body.

In this report, orthopedic surgeons from the Kobe University School of Medicine in Japan discuss the natural history of rheumatoid arthritis (RA) affecting the cervical spine (neck). They followed a group of patients (267 total) over a period of five years to see what happens over time. They hoped to see if it’s possible to predict who will develop cervical spine instability from RA.

Cervical spine instability is defined as movement, translation, or “slippage” of one cervical vertebra over the vertebra below it. Two other words used to describe this problem are translation and subluxation.

To form a true subluxation (partial dislocation), the vertebra has to slide at least two millimeters (as measured on X-rays). This measurement refers to the reducible difference.

In other words, when the bone is shifted and lined up as much as possible, there is still at least two millimeters of displacement. The shift can be in any direction (forward, backward, rotation, sideways). Most of the time, the displacement is anterior or forward.

Three types of cervical spine instabilities were studied: atlantoaxial subluxation (AAS), vertical subluxation (VS), and subaxial subluxation (SAS). The names were given based on the location or type of the displacement.

For example, the atlantoaxial (AO) joint is where the first cervical vertebra (C1 — the one just under your skull) sits on top of the second cervical vertebra (C2). Displacement of C1 over C2 is referred to as atlantoaxial subluxation (location of subluxation).

Upward movement of C2 toward C1 (type of displacement) is what is meant by vertical subluxation (VS). Subaxial subluxation (SAS) refers to location (subluxation of any cervical vertebra below C1-C2).

Patients with these types of cervical instabilities often report head, neck, and/or arm pain. There may be numbness and tingling or an electric shock sensation (called Lhermitte sign) down the arms if there is pressure on the spinal cord. Muscle weakness and atrophy are further neurological signs observed with this problem. The diagnosis is made using X-rays to confirm the location and position of the vertebra.

By performing serial (repeated) X-rays, the authors were able to observe progression of disease over time. They compared erosive joint destruction of the fingers with changes in the cervical spine.

Analysis of the data showed that early signs of cervical instabilities and worsening of hand involvement were two predictive factors for progression of cervical spine instability. In particular, vertebral subluxation (VS) and subaxial subluxation (SAS) followed the same pathway of worsening observed in the hands. As the hands got worse, the neck got worse.

In summary, the authors of this study refer to cervical instabilities as the most serious problem associated with rheumatoid arthritis (RA). Understanding and preventing cervical instabilities in this patient population is extremely important. A sudden shift of the vertebra putting pressure on the spinal cord can cause difficulty breathing and even death.

By observing early changes (as seen on X-rays) in the neck and hands, it is possible to target patients most likely to develop cervical spine degeneration. Preventing the risks associated with this problem is a more attainable goal now with the new disease modifying antirheumatic drugs (DMARDs) and biologic agents currently available.

The first report of long-term results with disc replacement for the cervical spine (neck) is now available. Patients in France treated with the Bryan Cervical Disc Arthroplasty were followed for at least eight years after surgery. This report gives us an idea of how well those 21 patients did past the first two to four years (which is the time period most other studies have reported on).

Artificial disc replacements were developed to avoid neck fusions and thus preserve neck motion. The idea came about when studies showed that cervical spine fusion often resulted in added wear and tear and degeneration of the adjacent (next level above or below) segment.

But there are concerns with the disc implants. They can migrate or move backwards in the spine. A position too far back can increase the risk of spinal cord or spinal nerve root compression. There is the possibility of subsidence (disc sinks down into the vertebral bone). Loosening of the implant and adjacent segment degeneration round out the list of possible problems or complications that can occur.

The disc system used (Bryan cervical disc arthroplasty) mimics the normal protective disc that acts like a cushion between two vertebral bodies. It is made of titanium on the outside with a plastic inside. The titanium endplate shells are covered in a double layer of porous coating to allow for better grip between the vertebrae.

Everyone in the study had good spinal alignment without any sign of instability. They had all tried conservative care without good enough results to bypass surgery. Patients ranged in age from 26 to 65 years old.

Results were measured using a variety of outcomes such as work status, activity level, symptoms (neck and/or arm pain), and neck motion. X-rays were used to assess the position of the device and to look for heterotopic ossification (HO).

With heterotopic ossification, there is additional bone formed outside the skeletal system. The extra bone usually forms in the surrounding soft tissues, especially the nearby muscles. It’s a problem because the artificial disc replacement (ADR) is designed to maintain joint motion. The heterotopic ossification reduces soft tissue mobility and causes increased stiffness.

The eight-year results were excellent. Three-fourths of the patients (18 of the 21) were free of neck and/or arm pain. They could perform all daily activities and chores without any problems. There were no neurological symptoms (e.g., no numbness or tingling down the arms, no change in deep tendon reflexes or sensation).

Heterotopic ossification (HO) was a problem in almost half of the patients. More HO seems to develop as time goes by. Not only do more patients show evidence of HO in time, those who develop it early start to progress to more severe cases. Having a two-level disc replacement is also a risk factor for HO.

Increased pain and decreased neck motion were linked with HO. The authors suggest several reasons why there was so much heterotopic ossification in these patients. First, the disruption of soft tissues and damage to the muscles is greater when more than one level is involved.

Second, patients in this study were not given antiinflammatory medications, which are known to reduce the risk of HO. And third, removing the diseased disc and damaged bone involves a special milling process, which may contribute to the body’s response making more bone.

As far as the other common complications developing (loosening, migration, subsidence, implant failure), there were none! There were three cases of spontaneous fusion (bone filling in around the implant) but no symptoms or functional problems as a result. No one had any further follow-up surgery.

About 19 per cent of the group did develop adjacent segment disease (ASD). That’s a striking finding since it has been believed that fusion is what causes increased degeneration at the vertebral segments on either side of the fusion. There is some speculation that ASD develops because there were already some degenerative changes present before disc replacement.

In conclusion, artificial disc replacement for the cervical spine (neck) is safe and effective. But it may not be without its problems. Patients who chose to have this procedure should be aware of the potential problems, risks, and benefits. More suggestions and guidelines can be made as other long-term studies are published.