Dynamic spine models designed by chiropractors. Our spine models are scientifically accurate, showing details in the discs, lumbar, pelvis and cervical spine. They can be used to demonstrate a range of clinical conditions which contribute to back pain or discomfort. Our models use an elastomeric two-part intervertebral disc design to show important anatomical features so are perfect for chiropractors, osteopaths, spine surgeons, physiotherapists and medicine students. See the back under compression and conditions such as disc herniation, epidural punctures and more.

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Accurate simulation of the herniated cervical intervertebral disc using controllable expansion: a finite element study

cervical degenerated herniated spine model

Goal of the Study?

The objective of this study 1 was to establish a three-dimensional finite element (3D-FE) model of the cervical disc and spinal cord to simulate an intervertebral disc compression injury of the spinal cord by controlling the expansion of specific parts of the disc model. 

herniated disc model

Why are they doing this study?

Cervical spondylotic myelopathy (CSM) is one of the most common spinal cord disorders in people older than 55. It is a degenerative disease that impairs the function of the spinal cord due to progressive and chronic compression. In advanced stages it can cause neurological issues ranging from neck stiffness, arm pain, numbness in the hands to more severe symptoms such as quadriplegia (tetraplegia).

To date, many of the in vivo and in vitro experimental studies focusing on impingement or compression are unable to simulate the sophisticated nature of spinal cord injuries. The authors speculate that computational models are better able to evaluate mechanical forces and spinal cord deformations. In particular, they argue that FE models may provide a way to more accurately simulate disc compression and therefore predict future deterioration and onset of CSM.

What was done?

The researchers developed a 3D FE (finite element) model of the cervical disc and spinal cord. This model was comprised of four distinct materials to represent the white matter, gray matter, pia matter and annulus ground. Cervical disc protrusions were simulated by applying thermal expansion to multiple FE unites to trigger bulging of the cervical disc either directly or indirectly.  

Three models of symmetric cervical disc herniation (median, paramedian and lateral) were created by evenly raising the temperature of corresponding FE units to 30 °C. The asymmetric hernia model was developed by rising the temperature of the paramedian type model gradually from 22 to 30 °C. They then used a linear regression analysis to determine the relationship between the various models and temperature changes.

What did they find?

Overall, the researchers found a correlation between rising temperatures and the gradual increase of severity of disc herniation. In all four models, herniated masses were observed at the region where thermal expansion occurred. In the asymmetric hernia model, the protrusion was more severe on the side with a high temperature increase than on the side with a lower temperature.  

They found that spinal cord compressions resulting from intervertebral disc protrusion were observed in all models, except the lateral type. The greater the cervical cord was compressed by the protruding disc, the larger the area with higher stress. Moreover, as the level of compression increased, the deformation of the spinal cord intensified and the stress was dispersed to the anterior horn and intermediate gray of the grey matter, which could explain the progression of neurological symptoms.  

Why do these findings matter?

A better understanding of the biologic mechanisms of spinal cord damage caused by chronic mechanical stress is required to improve diagnosis, treatment and clinical outcomes. In particular, FE models may provide a way to more accurately simulate disc compression  and herniated discs and therefore predict future deterioration and onset of CSM.

 

At Dynamic Disc Designs, we create models to help convey important teaching and educational instructions for students and patients. Explore our range of modeling.

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Vacuum sign indicating hypermobility? Degenerative Spondylolisthesis Study

vacuum sign

Vacuum sign is a common radiological finding. It is also referred to as a vacuum phenomenon and often associated with degenerative spinal discs, knee joints, hip joints, and shoulder joints.  Degenerative spondylolisthesis is a spinal condition whereby one vertebra slips on another. However, it is sometimes difficult to ascertain whether this slippage is stable or not. A more than 4mm movement defines instability, but some have indicated only 2mm as clinically significant.

degenerative spondylolisthesis model

Degenerative Spondylolisthesis Dynamic Disc Model

In a research paper published in World Surgery, 1 a group of authors looked at the vacuum sign in the facet joint as an indication of degenerative instability of the spine. They wanted to investigate the relationship between the vacuum facet phenomenon and lumbar instability. Why, you may ask? More and more research is directing spine researchers to the cause of pain and disability to the imbalance of motion of the individual vertebral segments of the spine. Some have coined this motion sharing.

Each vertebral motion segment consists of two vertebrae, and a disc should have a certain stiffness level. That is, it should move similar to its adjacent segment above and below in the spinal column. For this study, they looked at L4 on L5 (which is a prevalent spinal level to degenerate with age) and used flexion/ extension X-rays in both the fully bent forward (flexion) and the fully bending backwards (extension) with degenerative spondylolisthesis. Additionally, when available, they also looked at CAT scans of these same patients. To determine the slippage degree, they used a dynamic motion index to measure the degree of slippage.

In a total of 67 patients examined, 35 patients had vacuum signs on their CAT scan, and 32 patients did not. The degree of slippage appeared to correlate with the vacuum sign as well. That is, the more the vertebrae had slipped forward, the more likelihood of the presence of the vacuum sign. With this, the authors concluded a linear correlation between the degree of slippage and the presence of vacuum sign.

Vacuum sign

Vacuum phenomenon or vacuum sign and mobility

Commentary by Jerome Fryer

Vacuum sign or vacuum phenomenon is often considered an incidental finding. However, based on the modelling research I’ve done, I believe that the vacuum sign can be a clue into joint mechanics’ stiffness. In 2017 I published an article related to the cracking event we are familiar with, and in there, I believe in having revealed the vacuum phenomenon. In the presence of cavitation, a joint will have less stiffness, and in time I hope we can collectively use these radiographic findings to help us determine which joint requires more stability in the treatment of them. JF

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Lumbar Lordosis and Disc Herniation in Young Participants – Spine Research

lordosis. degenrative joint disease

Flat Back (Lack of Lumbar Lordosis) and Disc Herniation

Lordosis, or the lack of it, has been thought to be a biomechanical precursor to disc herniation in the lumbar spine. To investigate this possible correlation, a group of researchers from Gothenburg University looked at sixteen young active young patients with a median age of 18yrs old who experienced a disc herniation and underwent discectomy surgery. 1

Lordosis is the curve in the lower back—which they measured before and after the surgery.

Lordosis

Researchers used the Roussouly 4-type classification system to measure the degree of lordosis in the lumbar spine.

The researchers found less lordosis in the subjects that had surgery for their disc herniation. In other words, disc herniation was twice as likely to be present in the group with a flatter back. All the disc herniations were found to be in the lowest two levels of the lumbar spine (L4-5 and L5-S1), consistent with other epidemiological studies. 2

Dynamic Disc Designs Models

At Dynamic Disc Designs Corp. we have worked to represent the anatomy accurately. Our Professional LxH  Dynamic Disc Model is created with 12mm of disc height anteriorly and 10mm posteriorly providing a slight lordotic curve. Further, the model has been created with a higher percentage of nucleus pulposus which is often found in younger lumbar spines. To demonstrate that disc herniation occurs more likely with less lordosis all one has to do is dynamically move the single-level model into a less lordosis position and manually create compression. With more lordosis, the nucleus has a more difficult time penetrating through the outer annulus fissure. This can be an important posture teaching point in the prevention of disc herniation.

If you want to take your patient education to a dynamic level, explore what Dynamic Disc Designs models can do for you, your practice and ultimately, your patients.

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Does Oxygen Concentration and Culture Time Effect Metabolism of Porcine Nucleus Pulposus Cells?

A study 1 in the Frontiers in Bioengineering and Biotechnology investigated the in vitro glucose consumption as well as gene expression by NP cells (over time) while under varying oxygen tensions. The study’s objective was to gain data for understanding disc pathophysiology and to determine the therapeutic potential of notochordal NP cells.

Why such a Focus?

Low back pain or LBP is a common condition affecting millions of people around the globe. According to research, LBP has a relationship with the degeneration of the spine’s intervertebral discs. Furthermore, an imbalance in the catabolic and anabolic activity by disc cells is known to result in such degeneration. Due to intervertebral discs being avascular (in their nature), there may be an oxygen deficiency in the central NP or nucleus pulposus. While the mechanisms require further understanding, the matrix regulation and energy metabolism of the disc cells can be affected by the resulting hypoxia. Monitoring such affects might help with better LBP treatments down the line (including treatment and preventive strategies for degenerative intervertebral discs).

The Study

The current study cultured notochordal procine NP cells in agarose discs. The cultures were at 21, 5, or 1% oxygen tension for 1, 5, or 10 days. An RT-PCR was used to analyze the expression of 10 key matric genes, as well as Brachyury (T), by the said NP cells. A two-point method was used to measure the consumption of glucose.

Spinal bone

What were the significant Results?

The study’s results revealed that glucose consumption rates (by NP cells) were significantly affected by oxygen tension and culture time. Furthermore, significant changes were seen in T expression based on the culture time and oxygen level. Take note, better maintenance of the notochordal phenotype may be indicated due to how the T expression was significantly higher in the 1% oxygen tension on day 10 (compared to the other two groups).

What does it mean?

The study shared that (when it comes to agarose disc culture) a vital role is played by oxygen tensions level in maintaining the proper expression levels of matrix regulation genes of notochordal NP cells. The study offered data regarding the role of nutritional environment to support healthy NP cell expression. Better treatment strategies for disc regeneration might be helped by using the quantitative information gathered by this study. The data can also prove helpful to understand disc pathophysiology.

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Does Spinal Posture Act as a Trigger for an Episodic Headache?

Does Spinal Posture Act as a Trigger for an Episodic Headache

A review 1, found in Current Pain and Headache Reports was conducted to see if there was indeed a valid link between spinal posture acting as a trigger for an episodic headache. While the review concluded more research is required, it did present some interesting results.

The Global Issue of Headaches

According to the WHO (World Health Organization), headaches are one of the ten most disabling conditions for human beings. Numerous factors have been studied to contribute to or give rise to the development of a headache. Secondary headaches have been observed to be due to an underlying etiology, for example, trauma, infections, and dysfunctional or abnormal cervical structures. Take note, primary as well as certain secondary headaches arise from complex multi-dimensional interactions between lifestyle, psychosocial, cognitive, biological, and environmental factors. Due to several triggers, identifying underlying mechanisms of headaches continues to be challenging.

Headaches and Spinal Positions

The current world encourages people to remain seated. According to studies, when daily computer use exceeds 3 hours, there’s a higher prevalence of musculoskeletal complaints. Such complaints include experiencing pain in the neck, head, or upper extremity. These complaints are suspected to be linked to slumped sitting postures.

A slumped sitting position involves an increased posterior pelvic rotation, forward head posture, and thoracic flexion. Such postures (if sustained) tend to increase the biomechanical momentum and torque, decrease proprioception, cause creep of spinal tissue, and limit postural variability.

 

Headaches

Headaches and posture

Why do such a Review?

While an extensive framework for headache classification is provided by The International Classification of Headache Disorder, outcomes following physiotherapy do vary. Such variability might be explained due to the absence of protocol studies for identifying the role of spinal posture in headaches. That’s why conducting multi-dimensional profiling of patients (suffering from a headache) based on the interactions present between spinal posture, lifestyle, and psychosocial factors may be essential.

The current review had the objective to find support about whether spinal posture could trigger an episodic headache. The review considered a multi-dimensional view on tension-type and cervicogenic headache (this included modern pain neuroscience).

What Did It Find?

The current review described several pathways to support how spinal postures acted as a trigger for an episodic headache. Psychosocial factors could also act as a catalyst for the development of a headache through a maladaptive spinal posture.

However, further research is still required to determine the exact level of contribution of spinal postural dysfunctions and their ability to trigger a headache.

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Does the Human Body Hold Potential for Improved Regeneration?

Does the Human Body Hold Potential for Improved Regeneration

A recent study 1 from the journal Science Advances analyzed protein turnover that occurs in articular cartilage from lower limb joints in humans. The results showed a potential for regeneration that could likely be exploited to improve joint repair.

What was the Context?

While regeneration exists in certain animal species, humans are believed not to have the ability to counter cumulative damage. In this context, the said type of damage is caused by repetitive joint use as well as certain injuries due to which cartilage breaks down and gives rise to osteoarthritis (OA). According to previous research, the turnover of insoluble collagen in human adult cartilage has been suggested to be quite limited. However, take note, humans do have the limited regenerative capacity. For example, during childhood, the regrowth of distal portions of amputated digits has been observed.

miRNA has been observed to play a significant role in regeneration; however, miRNA’s regenerative role is low in humans. The current study set out to explore the articular cartilage’s protein turnover (in the human lower limb joints).

The Design

The current study collected articular cartilage (as waste surgical specimens) from Duke University Hospital. The full-thickness cartilage was collected from the hip, knee, and ankle joints from patients that had end-stage OA who had undergone total arthroplasty surgery. Take note; the cartilage was from the perilesional regions of the hip, knee, and ankle joint’s load-bearing area.

A total of 18 samples were collected. The samples included three types of joints (hip, knee, and ankle), two types of disease state (healthy as well as OA), and three biological replicates of each type with matched age range. The mean age of healthy non-OA patients was 58.8 years. Their age range was 30 to 82 years. Also, the mean age of the patients with OA was 59.8 years (with the range being 42 and 87 years).

The analysis was performed on a quadrupole Orbitrap benchtop mass spectrometer (Q Exactive) equipped with an EASY-nLC 1000 system. Furthermore, protein identification was performed using the Homo sapiens taxonomy) setting of the Swiss-Prot database with Proteome Discoverer 2.1.

Also, miRNA quantification was done by a real-time polymerase chain reaction. The Deamidation rate was analyzed using the Swiss-PdbViewer.

What were the Results?

The study demonstrated a position-dependent gradient (distal high, proximal low) of protein turnover in human lower limb cartilage. The findings of this study have helped reveal a dynamic anabolic effect in human limbs that showcase a potential (limited) natural regenerative capacity in human cartilage.

According to these results, increased expression of matrix proteins is seen in OA knee cartilage. Also, the higher prevalence of hip and knee OA (compared to ankle OA), might explain the lack of repair in proximal joints.

What was Concluded?

The results suggested the role of regenerative miRNA present in cartilage homeostasis, intrinsic repair capacity, and turnover. Also, the limited regenerative capacity in humans is proposed to be primarily controlled by location rather than the shape of the joint or loading. The use of in vivo protein deamidation molecular clocks helped find a distal-proximal gradient of protein turnover.

The current data also suggested that anabolic treatments may be required in addition to anticatabolic treatments, especially for human hip joints, to prevent or, at least, slow OA’s rate of progression.

The study concluded that more functional studies on the effects of these associated miRNAs would be required to further reveal their regulatory role in cartilage repair and to help prevent certain ailments (including Low Back Pain).

Interestingly, the study suggested that injection of key regenerative miRNA in a joint (either singly or in combination) might have the potential to improve endogenous repair and help resist the degeneration of joint tissues in all types of arthritis.

 

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Can Verbal Suggestions Manage Musculoskeletal Pain? A Review

Can Verbal Suggestions Manage Musculoskeletal Pain A Review

How much of an impact do verbal suggestions have on managing pain? We can’t be entirely sure. There has been a lot of controversy surrounding the power of suggestion and pain management. A review 1, in the journal of Physical Therapy Reviews, was conducted to find some answers. While there is potential in such a field, more research is required to see any clinical significance associated with pain management and verbal suggestions.

What’s the Context?

Numerous studies prove that pain has socioeconomic and health implications. This includes disability and functional limitation. Chronic lumbar pain has been observed to have the greatest prevalence. Low Back Pain or LBP is an economically draining ailment for individuals around the globe. Furthermore, reduction in pain due to surgeries and other LBP treatments isn’t always accompanied by improvement. Due to LBP being multi-faceted (including psychological factors), a person’s psyche has been suggested to help with recovery. So, verbal suggestions might have a role to play in the treatment of LBP.

Musculoskeletal lower back pain

The Purpose of This Review

The aim of the current review was to describe as well as explore the neurobiological mechanisms associated with verbal suggestions when it came to managing musculoskeletal pain in patients.

The literature search was conducted by two independent reviewers. The databases included were PEDro databases, Medline, Cochrane Library, Lilacs. Systematic reviews, randomized clinical trials, and literature reviews were included in this review.

After the study’s exclusion criteria, a total of 13 studies were involved in the current review. The total included four randomized controlled trials and nine reviews. The current review covered the neurobiology of verbal suggestion, and the effects of verbal suggestion in pain sufferers.

What did the Review Conclude?

The review concluded that there’s potential in positive verbal suggestion to improve the effectiveness of LBP management in patients. The review pointed out that such suggestions could generate hypoalgesia via the placebo effect. However, more research is required to fully determine the clinical significance of verbal suggestions for pain management in patients.

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