Our dynamic cervical models help a practitioner convey important relevant anatomy to patients to help empower the individual who may be struggling with cervical related pain.

Cervical Herniated Disc

Goal of the Study?

In this review 1 the authors examine 76 cases of spontaneous herniated cervical discs and one direct patient experience to understand the phenomenon better.


Why are they doing this study?

Spontaneous regression of herniated lumbar discs has been well researched. However, spontaneous regression of herniated cervical discs has not been examined to the same extent. For this reason, the authors felt it essential to do a review of the existing literature, as well as one case study.


What was done?

Using PubMed and EMBASE databases, the authors found 75 cases that related to “spontaneous regression,” “herniated cervical disc,” and “MRI studies.” Patients averaged 41 years of age and were split equally male and female. In addition, they used a case study of one patient who had been experiencing neck pain for three weeks, right upper extremity radicular pain and right C7 distribution weakness and numbness. This patient’s cervical MRI showed a suitable paracentral disc extrusion at the C6-C7 and right C7 root compression. The patient did not want surgery and instead chose management with pharmaceuticals. At the same time, he reported improvement, three months after an MRI showed spontaneous regression of the C6-C7 disc extrusion.


What did they find?

The most predominant symptoms identified in the literature review were neck pain or radiculopathy (91%) and myelopathy (9%). The discs were paracentral or foraminal in 61 cases (84% of the total cases) and central in 12 cases. The literature illustrated a higher incidence of spontaneous disc regression in the paracentral/foraminal lesions. Discs mainly were located at the C5-C6 (31 cases) and C6-C7 (22 cases) and were most frequently extruded or sequestrated. The average period between the initial presentation and spontaneous regression of herniated cervical disc on MRI scans was 9.15 months. Using MRI, the studies illustrated that extruded/sequestrated discs were more likely to undergo spontaneous regression than protruding discs.  


Why do these findings matter?

Reviews such as this can better understand how and when to treat spontaneous regression of herniated cervical discs.

Do you have a model to show this regression?

At Dynamic Disc Designs, we have models to help show patients the retraction of the nucleus pulposus to assist in the management and education of patients with disc herniation.

smartphone overuse

Goal of the Study?

In this study, 1, the aim was to investigate the association between nuchal (neck) pain, psychological impairment and smartphone overuse (SO) in office workers.


Why are they doing this study?

The use of smartphones is prevalent, with most people spending multiple hours a day using them for work and personal life. The prolonged use of smartphones can lead to neck disorders due to users’ neck flexion posture as they look at the screen for prolonged periods of time. Most smartphone tasks require users to stare downwards and hold their arms out in front of them, making the head move forward and causing an excessive anterior curve in the lower cervical vertebrae and an excessive posterior curve in the upper thoracic vertebrae to maintain balance. This forward head posture (FHP) may increase stress on the cervical spine and neck muscles. Research has shown that incorrect posture of the neck and head is associated with chronic musculoskeletal pain. Therefore, the increased use of smartphones at work is an important aspect of the study.


What was done?

The authors conducted a cross-sectional report of a cohort study between May 2018 and July 2019, with 1602 office workers (575 males and 1027 females). To be included in the study, participants had to be at least 18 years of age and have more than 4 years of smartphone use. People were excluded if they had a history of cervical trauma or any congenital abnormalities in the spine. 

The researchers assessed a range of data including demographics, abnormal symptoms of pain in the neck, physical activity and psychological behaviour — using scales to measure smartphone addiction, depression, anxiety and stress, as well as physical activity.  Multiple regression was used to evaluate the relationships.


What did they find?

The overall prevalence rate for neck pain was 30.1%, with significantly more females and younger workers reporting neck pain than others in the sample. The researchers also found with higher physical activity, less neck pain was reported. Those with vigorous, moderate and light activity had different reported neck pain levels with 7%, 25.5% and 31.5%, respectively. 

The prevalence for SO was 20.3% and was more common in younger male workers. Office workers with SO showed a higher prevalence of neck pain (62.9%) than people without SO. Additionally, single office workers had 1.6 times more risk for SO compared to married workers. Overall, those with SO were approximately 6 times more likely to have neck pain.

The researchers also found a significant correlation between neck pain and depression, anxiety and stress, with 26.6% of the workers with severe depression, 31.3% severe anxiety and 36.6% severe stress. Moreover, those with severe depression had a 70% more chance of neck pain


Why do these findings matter?

With the increasing reliance on smartphone use in modern life, the relationship between SO, neck pain, and psychological suffering found in this study is important information. The authors argue that there is a need for research on preventing the negative outcomes of SO. 


Cervical Spondylosis

Goal of the Study?

In this study, 1 the researchers investigated the association of prior cervical spondylosis (CS) diagnosis with peripheral vertigo in Taiwanese patients.

Why are they doing this study?

CS is an age-related condition resulting from deterioration in the spine, with a prevalence rate of more than 50% among those over 40 years old. While not all patients will have clinical signs of disease, symptoms can range from tingling, numbness, pain in the neck or arms, stiffness, headaches, vertigo, and balance loss.  Peripheral vertigo is often observed with CS and is one of the most common reasons patients get medical care.

The authors state that despite the wide prevalence, to date, no population-based studies are looking at the association between CS and peripheral vertigo. 

What was done?

The researchers used a case-control study design, selecting cases of peripheral vertigo and matched controls. They used the data from the Taiwan Longitudinal Health Insurance Database 2005 (LHID2005), which consists of all registration riles and medical claims data for a stratified random sample of 2 million enrollees.

They identified all those ≥ 18 years old who had received a diagnosis of peripheral vertigo between January 1, 2010, and December 31, 2016, which totalled 2,570 patients. These were compared to a control group of 7,710 patients from the same dataset (with 3 controls per one case), matching based on patient demographics such as age, sex, income, geographic location and medical comorbidities associated with increased risk of vertigo. They excluded all patients less than 18 years old and those who had never been diagnosed with peripheral vertigo.

They then used a statistical program to estimate determine the relationship between prior CS occurrence among peripheral vertigo patients versus controls. 

What did they find?

Overall, the researchers found that CS is associated with peripheral vertigo, particularly with those patients aged 45 to 64. This association is consistent with other research and may be caused by a range of issues, including cervical instability, inflammatory cytokine stimulation, and more.  They also found that CS with myelopathy (an injury to the spinal cord due to severe compression) is not associated with peripheral vertigo. 

They did not find any significant differences based on demographics. In particular, they did not find that patients over 64 years of age with CS had a higher risk of peripheral vertigo.


There are a few limitations outline by the authors. First, they state that claims data may not be as precise as information based on a clinical examination, resulting in some misclassification between types of vertigo. Second, there is a lack of data on potential confounding variables such as family history, lifestyle, etc. Finally, the vast majority of the study population are Han Chinese, and therefore the results may not be generalizable to other racial and ethnic groups. 

Cervical Spondylosis

Cervical model

Why do these findings matter?

As peripheral vertigo often occurs with CS, it is important to understand the relationship between the two conditions better to diagnose better and treat patients.  

Upper Cervical Spine Model

A study 1 published in The Spine Journal shared interesting results about CT exams and detecting upper cervical spine injuries. The conclusion hoped the current study’s data might help with earlier detection of craniocervical dissociative injuries.

Why Conduct Such a Study?

Research shows that in fatal cervical spine injuries, the common findings are traumatic occipitocervical (or OC) injuries. These OC injuries include damage being done to the OC as well as AA (atlantoaxial) articulations.

The more traditional diagnostic methods for the evaluation of the human upper cervical spine made use of the relationship between the cervical spine and the skull. It used lateral radiographs for visualization. However, the said method tends to have limited sensitivity as well as specificity. That’s why CT (computed tomography) scans ended up being used more. But, even then, the parameters for identifying normal and abnormal CT anatomy (especially in the upper cervical spine) need more clarity.

The current study was conducted to offer details of the normal anatomical features as well as upper cervical spine relationships, as displayed on the CT scan. The goal was to establish better threshold measurements when it comes to detecting subtle cervical injury or abnormality.

The Method Used

The design of this study can be defined as a retrospective anatomical case review. This study’s patient population was 100. All of them had undergone a screening CT scan (multidirectional) of their cervical spine. The research team randomly selected patients by using the radiology teaching file as well as the trauma registry databases. All of the scans were deemed negative for trauma (focusing on the craniocervical junction).

A total of 76 cervical CT scans (thin-sliced) were randomly selected for this study. Take note; the team made 42 different anatomical measurements of the upper cervical spine.

What Did the Results Conclude?

The results showed the least variation in direct measurements. The mean OC joint space came in at 0.6 mm, with the AA joint space being 0.6 mm. Significantly higher standard deviation as well as variability was demonstrated by the midsagittal structures.

The current data was used to reach certain conclusions. There was no variance (according to demographics) when it came to the left-right symmetry and narrow joint spaces in the cervical spine joints. The consistency in the coronal plane was regarded as the factor enabling precise diagnostic measurements and comparisons. According to this study, such precision can help with accurately identifying abnormal scans.

A better understanding of upper cervical spine-centric relationships may help with earlier detection of subtle craniocervical dissociative injuries (dependent on the data from CT scans). A subtle misalignment could serve as evidence for a severe injury when looking at CT scans.


What are the Risk Factors Associated with Recurrent Lumbar Disc Herniation After Discectomy

Not many reports address whether LSTV (Lumbosacral transitional vertebrae) has a link with LDH (Lumbar disc herniation). A study 1, in the journal International Orthopedics, was conducted to rectify that. The results showed that LSTV and a hypermobile disc in flexion-extension radiography were risk factors for recurrent LDH.

What was the Context?

Reports show that LDH is a common complication following discectomy. The reported frequency has been observed to be up to 21%. The previous operation site was where the recurrence was the most frequent. Patients were likely to experience pain in the legs and back. They might even require revision surgery.

There’s still controversy present with regards to the risk factors associated with recurrent LDH. There are a lot of conflicting results. While gender, age, obesity, and smoking status are considered risks, radiological factors might be risk factors, too. These factors include disc degeneration, larger sagittal range of motion (SROM) in flexion-extension radiography, and larger disc height.

The Study

The current study investigated numerous risk factors for LDH following discectomy. The study involved a total of 119 participants. All of them had undergone a discectomy for L4-5 disc herniation. The minimum follow-up was of two years.

The study evaluated a range of risk factors. The clinical parameters involved body mass index, smoking status, and gender. The radiological parameters were LSTV, degree of disc degeneration, SROM, and type of herniated disc.

Disc Herniation

What were the Results?

The results showed that 21 of the participants had recurrent disc herniation at L4-5. From the 21 patients, 11 had LSTV. Seven patients had LSTV in the 98 patients from the non-recurrent group. The study shared that it had confirmed LSTV and a larger SROM being significant risk factors at L4-5 (for recurrent disc herniation).

What does it Mean?

The current study, deemed to be the first of its kind, concluded that LSTV and a hypermobile disc in flexion-extension radiography were indeed risk factors for recurrent LDH. The current data can offer beneficial knowledge for future research.


A 2018 study 1 of resting state functional magnetic resonance imaging (rs-fMRI) of the cervical spinal cord in fibromyalgia patients and control subjects found there was greater ventral and lesser dorsal Mean ALFF of the cervical spinal cord in patients with fibromyalgia, compared to the control group subjects. The results of the study may indicate that fibromyalgia patients experience enhanced sensitization of nerve responses that could be responsible, in part, for the discomfort and fatigue associated with the disorder.

What’s at Stake

Patients with fibromyalgia report the experience of physical pain throughout the body, as well as cognitive problems, fatigue, anxiety, and depression. The symptoms may be a result of irregularity of the central nervous system (CNS), including central sensitization and possibly a decreased ability to modulate pain responses. Signals to and from pain receptors may be misdirected or skewed in patients with fibromyalgia, creating an altered response to nociceptive and non-nociceptive signals.

Previous imaging studies have demonstrated altered CNS activity or structure and irregular brain activity in response to painful and non-painful stimuli in fibromyalgia patients.  Functional connectivity, networks, and low frequency oscillatory power have been measured through resting state functional magnetic resonance imaging (rs-fMRI), but these studies did little to elucidate the underlying CNS processes that occur in patients with fibromyalgia. Because of the complexity of the CNS signals in the spine, it was necessary to conduct a comparative rs-MRI of healthy controls and fibromyalgia patients to observe alterations of oscillatory frequencies, functional CNS connectivity, and analyze the graph metrics of the fibromyalgia patients.

The Study

The study subjects included 16 fibromyalgia patients whose symptoms met the American College of Rheumatology inclusion criteria for fibromyalgia and 17 healthy participants. Subjects with MRI contraindications, taking opioids for pain or mood-altering medications, and those with depression or anxiety disorder were excluded, as were pregnant or nursing females. All subjects were screened for MRI contraindications and filled out questionnaires regarding their psychological and behavioral state, diagnostic pain, sensory, and fatigue criteria prior to the study.  Further testing assessed the subjects’ sensory, pain, cold pressure response, mechanical hyperalgesia, and mechanical temporal responses.

Each of the subjects was queried regarding their levels of pain prior to, and after their fMRI scans, using a scale of 0 to 10 to grade their pain. Separate amplitude of low frequency fluctuations (ALFF) Measures of Mean were calculated for each study subject across all voxels of the cervical spine data. Normalized images were analyzed for differences, and the significance of the findings was assessed. Gray and white matter Mean ALFF was also analyzed and compared in the study groups. The functional organization and connectivity of spinal cord networks was also observed and compared in both study groups, as other studies have suggested that bilateral motor, sensory, and dorsal horn functional connectivity networks was altered during thermal stimulation in humans and after a spinal cord injury in non-human primates. The researchers in this study wanted to investigate if disrupted spinal cord processing and functional organization may be responsible for some symptoms of fibromyalgia.


Results & Conclusions

The fibromyalgia patients had higher measures of fatigue, sensory hypersensitivity, and widespread pain than the control group. Each of the fibromyalgia patients had right shoulder pain, and most experienced arm pain, undermining the research expectation that the patients’ sensitization would be central and found throughout the CNS as a result of their altered cervical spinal cord activity.

The ALFF spinal cord low frequency oscillatory power study indicated a greater Mean ALFF in the ventral hemi-cord of the fibromyalgia patients. The dorsal quadrants of fibromyalgia patients showed lesser Mean ALFF. Mean ALFF was higher in gray matter than in white matter in the patients.

Overall, the study demonstrated that the cervical spinal cord of the fibromyalgia patients had altered patterns of rs-fMRI low frequency power—greater regional Mean ALFF in the ventral, and lesser in the dorsal spinal cord. The most pronounced difference was noted inside a small cluster in the right dorsal quadrant, at the border between the dorsal horn gray and white matter. There was a strong correlation between levels of patient fatigue reported and the noted differences in Mean ALFF. These observations support the idea of regional differences in nociceptive and non-nociceptive CNS processing pathways in patients with fibromyalgia.

While there is a need for future study of local spinal cord modulatory circuits, these findings suggest that a combination of reduced CNS inhibition, coupled with an increase in dorsal horn excitation could be responsible for the irregular modulation of sensory and pain signals experienced by patients with fibromyalgia. Nociceptive signals might be over-transmitted by spinothalmic projection neurons, and/or a similar process could cause the under-transmission of non-nociceptive signals. Irregular spinal cord signal modulations (decreased, or increased) could increase or lessen signals of any type to any part of the body, which might explain the experience of uncomfortable hot or cold sensations in patients with fibromyalgia. There was also a very strong correlation between the Mean ALFF of the fibromyalgia patients and their fatigue symptom measures.


Treatment strategies related to intervertebral disc displacement often involves extension. Robin McKenzie’s work on centralization of symptoms in the case of disc herniation has been used by many.  Most of the research on migration nucleus pulposus has been previously investigated in the lumbar spine. In a recent study published in PM&R 1 , researchers looked at the cervical spine and wondered if this was a similar case. They hypothesized that cervical extension would centralize and shift the nucleus anterior–away from the associated disc herniation.

They looked at 10 healthy young males with mean age of 22 yrs old and compared neutral to extension position of the cervical discs using MRI. They carefully mapped out the nucleus pulposus and found that in extension the migration nucleus pulposus was anterior and away from the posterior disc margin.

They concluded that moving the cervical spine into extension could be clinically valuable in the case of cervical disc problems.

At Dynamic Disc Designs, we have seen what these researchers have seen! When our handcrafted models (with an annulus and nucleus) are moved into extension, the nucleus can been seen to move anterior. In our lumbar models, the clear L4 vertebra of our Professional LxH Model allows full migration visibility of the nucleus pulposus. This is helpful in the clinical explanation of treatment targets for patients with intervertebral disc problems.

migration nucleus pulposus, lumbar model

Posterior nucleus migration in flexion.

  1.  Kim YH, Kim SI, Park S, Hong SH, Chung SG Effects of Cervical Extension on Deformation of Intervertebral Disk and Migration of Nucleus Pulposus. PM R. 2016 Sep 6. pii: S1934-1482(16)30905-4. doi: 10.1016/j.pmrj.2016.08.027. [Epub ahead of print