Our patient education dynamic spine models help low back pain sufferers better understanding of their pain sources.

A dynamic spine model can empower a patient to help him or her get to know the motions postures and loads related to pain. Once the specific movements are identified, a patient can learn what exercises and movement strategies that will reduce their symptoms. A disc bulge is often an MRI finding but it can also tells a story about hypermobility. For lumbar spinal stenosis, it is also common for a person to have symptoms while their spine is in relative extension. The Lumbar Spinal Stenosis Model helps a practitioner deliver this important message to engage with accurate patient education.

Goal of the Study?

Lumbar spinal stenosis affects approximately 11% of the population, primarily in the adult population.1 In this article, the authors worked to provide a clinical update giving practitioners a “what you need to know” perspective on the ins and outs of clinical practice.


Why are they doing this study?

Because of its prevalence and challenge to accurately diagnose, it is important to understand the clinical presentation of lumbar spinal stenosis from a symptomatology standpoint. This careful attention to a patient’s symptoms can help guide an appropriate care plan. The clinical challenge can be cloudy as other conditions like vascular claudication can lead even the best clinicians down the wrong diagnostic path.


What was done?

A review of the anatomy is important when understanding the clinical symptoms of lumbar spinal stenosis. In this clinical update, the authors revisit the degenerative changes of the spinal canal and the intervertebral foramen related to spacing and the nerves that travel through these spaces.

Spinal Canal Spacing, Lumbar Spinal Stenosis Education Model

Lumbar spinal stenosis model


What did they find?

As the discs lose height, the associated anatomical changes can lead to narrowing. Degenerative discs lose height over time, and in doing so, the facets approximate, leading to hypertrophy of the bony architecture. Facet arthropathy (as seen in the Lumbar Spinal Stenosis Dynamic Disc Model) can take up valuable spinal real estate for lateral recess and intervertebral foramen; furthermore, discs lose height, discs bulge. And with this bulging, just as a tire bulges when it loses air pressure, it can often take up spinal canal spacing. This can also lead to the ligamentum flavum bulging itself (also thought of as buckling or thickening), encroaching on the valuable room the vasculature around the cauda equina must have to function.

The classic presentation is the patient reporting of not being able to distance walk as they have previously. They also report that standing often generates lower leg symptoms or buttock/leg weakness and relief of these symptoms by sitting and/or using the upper extremities to offload and flex the spine, like that seen with the shopping cart posture.

The authors point out that lateral recess stenosis and foraminal stenosis can mimic radiculopathy as seen in sciatica related to a disc herniation and report that a combination of these symptoms and subtypes is common.


How is Lumbar Spinal Stenosis Diagnosed?

A careful history and examination are at the roots of a proper diagnosis. Imaging has been relatively unreliable and likely due to the static nature of MRI and CT. It is suggested that clinicians can ask suspected patients to walk or to have patients extend the lumbar spine for thirty seconds to recreate the symptoms.

The authors have created these points and to be mindful of patients over 50 present with these symptoms:

  • pain in lower extremities/buttocks while walking
  • flexion to relieve
  • relief if using the upper extremities to push down and generate lumbar flexion like that seen using a shopping cart or riding a bicycle
  • unsteady motor disturbance while walking
  • tingling or numbness in the legs while walking
  • pulses equal and bilateral in lower extremities
  • low back pain


How do Clinicians Talk about Lumbar Spinal Stenosis with their patients?

Lumbar Spinal Stenosis Model

What tools do you use to educate your patients?





Goal of the Study?

These researchers sought out to answer the question of does reassurance helps patients with acute low back pain? In this study 1, the authors looked at two hundred and two people with acute low back pain with a high risk of developing chronic low back pain. They were curious as to whether helping someone with supportive psychological language could help reduce disability outcomes.


Why are they doing this study?

The current zeitgeist and research push has emphasized reducing nocebic iatrogenic influences and steering away from the biomedical model. This has naturally led to alternative strategies like the use of emphasized reassurance tools.  However, does this strategy alone make a difference?


Bulging Disc Model


What was done?

Using a  randomized sham-controlled clinical trial mediation analysis, these researchers compared patient education to sham patient education. Enrolled participants listened to either: 1. two 1-hour sessions explaining the benign aspects using a biopsychosocial framework. 2. two 1-hour sessions that included active listening only, as of the sham comparison.


What did they find?

Those that did receive patient education did express improved re-assurance(compared to the sham); however, this did not lead to improved disability scores or was associated with health care use frequency. All in all, the results demonstrated there was no association with participants feeling reassured and improved outcomes.



The main limitation was the length of patient education in this study. This is obviously much longer than what clinicians often employed in clinical practice. The authors also suggest that less time would unlikely result in a different outcome.


Why do these findings matter?

Clinicians have been encouraged to use reassurance in the case of many clinical conditions.  The authors suggest that although patient education can be effective, overemphasis does not lead to better outcomes. Clinicians with their clinical time restraints should be selective in the time allocated to specific topics. The authors suggested that perhaps more time listening and matching appropriate treatment strategies may be a better option with time management restrictions.


Dynamic Disc Model

Goal of the Study?

In this study 1, the authors attempt to build a three-dimensional finite element (FE) model to investigate how changes to the nucleus pulposus (NP) under axial compression loads influences bulging in the lumbar disc. 


Why are they doing this study?

The intervertebral disc provides cushioning between vertebrae and absorbs pressure on the spine. A disc herniation happens when the annulus fibers are weakened or torn, and the NP pushes through the annulus fibrosus (AF). This bulging can generate pressure on the adjacent nerve roots causing lower back pain (LBP) and may even lead to paralysis. 

Existing research suggests that under the same compression the extent of the bulging differs by area, with the posterior region experiencing the least amount of bulging. Taking this knowledge into consideration, the authors argue that it is important to understand the behaviour of bulging in the disc to prevent severe damage and provide a path to more effective treatment. 


What was done?

The researchers created a 3D FEA model that simulates a functional human spinal unit of the lumbar region under axial compression loads. The material properties of the AN and NP are assumed to be linear elastic and the structure of the AF is modeled as a homogeneous material without fibrin. 

To validate the model, the authors looked at the axial and bulging displacements under axial compression load and compared that to existing data. They further validated their model by comparing the distribution of stress in the AF with and without the NP.


What did they find?

The researchers found that the condition of the disc (partial removal, full removal or intact) significantly affects how the disc bulges and where. For example, they found that for a disc without an NP the posterior region bulges inward. In contrast, for both an intact NP and with partial removal of the NP, the bulging occurs outward due to increasing pressure at the central part of the AF. 


Why do these findings matter?

The findings can help to improve treatment decisions of the degenerative disc and nucleus pulposus.


Goal of the article?


Back pain is very common in people who practice sport at the elite and non-elite levels. In this article 1, the authors look at the existing research to understand how physical exercise can impact biologic and structural changes to the intervertebral disc (IVD) and spine. 


What is the IVD?


The IVD is the hydraulic cushion between vertebrae, making up almost one quarter of the spinal column. IVD provides stability by absorbing and distributing the stress and shock of the body during movement and preventing the vertebrae from approximating one another. Each IVD is made up of two parts: 


  1. Annulus fibrosis – this is the outside of the disc, made up of water and elastic collagen fibers
  2. Nucleus pulpous – this is the inside of the disc, made up of a gel like elastic substance


What did they find?


Research shows that different types of exercises have different outcomes for the IVD and spine. Low-impact and moderate physical exercise are beneficial to IVD as they can promote regeneration and muscle function. For example, regular walking or low demand running can help to improve IVD structure and support by providing nutrition to the IVD in the form of oxygen and lactate. 


In contrast, high impact activities that over rotate the spine or force it to overly compress can break down the IVD early and result in back pain. This pain can result in a reduction in muscle strength and muscle activation. It can also result in a worsening of coordination and proprioception (the sense of self-movement and body position). This means that individuals with lower back pain can have a reduced ability to sense how the body is moving and its’ actions. 


However, not only does pain have an impact on how a person can move, but it can also result in changes to the brain or what is called cortical neuroplasticity. These brain changes can alter the body’s motor and behaviour control. They can also limit the effectiveness of learning a new skill by reducing the ability of an individual to make necessary adaptions to movements that further deteriorate the spinal tissues. 


Why does this review matter?


Back pain is a very common finding in exercise and sport. Therefore, it is important to understand what types of exercise are beneficial to IVD and what types can deteriorate the spine and spinal tissues. Understanding how prolonged back pain can change the way human bodies experience and adapt to pain, and the long-term impacts that can have on learning a new skill, are important to addressing treatments for patients living with back pain. 


At Dynamic Disc Designs, we work to model the biology of the spine in a flexible and interactive way so professionals can make the best clinical decisions for their patients.




Goal of the study?


To evaluate the frequency of lesions (injuries) in the lumbar region (lower back) of asymptomatic adolescent soccer players using MRI.


Why are they doing this study?


To date, there are very few studies that look at the frequency of spinal lesions in young athletes. Most of the research has focused on adult athletes and has shown that the lower back region is the most common site for problems. However, we know that the pediatric musculoskeletal system is particularly at risk to injury because adolescent bodies have not finished growing. Injuries at such a young age can result in an imbalance in bone tissue and muscles, which may cause an increased risk of injury, pain and limit young adolescents’ daily activities. These injuries can also get worse as we age. Therefore, it’s important to know if adolescent soccer players are getting lower back lesions that are not being identified and treated.



Modic Model


Who was involved?


The study 1 looked at two groups of asymptomatic male adolescents aged 13-18. 


  1. Soccer players who practiced the sport for at least two consecutive years, at least three times per week for 1-3 hours.
  2. Control group was made up of asymptomatic adolescents and was matched for age, gender, height and weight. They could not play soccer or any other sport more than once a week for more than 1 hour.


  • No one in the study could have any history of lesions, surgery, chronic disease or a high BMI score.
  • While they originally recruited 60 adolescents (30 in each group), because of exclusions the final sample size was 45.


What was done?


The researchers used MRI to evaluate the spine and look for the frequency of lesions in the lower back of adolescent soccer players. 


Two different radiologists examined the MRI images looking for the presence or absence of swelling, protrusions and disc extrusions (bulges). They also looked at stress reactions, cracks or stress fractures in the vertebras, vertebras slipped out of place, enlargements or growths, as well as swelling of the interspinal ligaments and muscles. 


What did they find?


Comparing the two groups, the researchers found that the proportion of spinal lesions was 76% in the soccer players compared to only 35% of the control group. In particular, they found that the percentage of lesions in the anterior and posterior of the spine was significantly higher in the soccer players than the control group. They did not find any significant differences between the age and BMI Z-scores between the two groups.



This study was able to show a high number of lesions in soccer players compared to other youth soccer studies that did not use MRI. However, research on young athletes playing other sports shows a similar frequency of spinal lesions.


What are the limitations?


This study had a very small number of participants. Also, all of the soccer players were studied during their championship season. This means it is likely that they are doing more intense training and playing than during regular season. As of Dec 28, 2020, the paper is still under review and going through the editorial process.


Why do these findings matter?


Lower back injuries in childhood and adolescence can lead to early degenerative changes. Therefore, the high number of lower back lesions in adolescent soccer players should be considered in the changing landscape of a person’s spinal health. Sport specific prevention efforts are important to reduce the occurrence and impact of lower back injuries on young adolescents. Better identification and management of spinal lesions may help to ensure that young people are able to continue playing sport and reduce the impact of these injuries in adulthood and into their senior years to avoid conditions like lumbar spinal stenosis. Learning recovery strategies show promise.

facet osteoarthritis, facet joint pain

Facet osteoarthritis pain is common and thought to be a significant contributor to back pain in the US. Within the United States, it costs 100 Billion dollars annually to combat this endemic problem. However, back pain can originate from many anatomical structures, and the facet joint is only one of them but thought by many as significant. Other common pain structures are the intervertebral discs in the case of disc bulges, disc extrusions, disc protrusions and frank nuclear sequestration. There are also more severe causes of back pain like aneurysm and other organ pathology, so it is crucial to have a professional look carefully at the diagnostics of each case.

In the case of mechanical lower back pain (others use the term non-specific lower back pain), the facet joint garners good attention. The word ‘facet’ comes from the French facette (12c., Old French facete), diminutive of face “face, appearance” and are two anatomical structures that reside behind the intervertebral disc.

Facet osteoarthritis

Modeling facet osteoarthritis is tricky because of the complexity of motion at the spinal level. The intervertebral disc height plays a role with respective facet compression because it resides on the front of the spinal motion segment. It is this compression thought to be contributing to back pain.

Clincally, facet osteoarthritis pain is often unilateral in nature

In a study conducted recently 1, researchers worked to induce facet joint arthritis by creating compression with a spring. Over time the researchers found the increased expression of interleukin‑1β and tumour necrosis factor‑α expression. In other words, with more compression elapsing over time, the more the expression of the molecules related to many low back pain patients.

This is an important study linking the mechanics of compression and the associated physiology of molecules, which are thought to be markers of back pain patients.

At Dynamic Disc Designs, we have developed models to help explain the associated compression of facet joints as it relates to disc height loss and gains. We are committed to bringing the best in modelling. Explore our website for more.

Crack Propagation Osteoarthritis

Osteoarthritis is common and causes much disability in the world to many. It is a joint condition that causes pain, which often leads people to seek therapy. Despite the efforts to learn the underlying causes, researchers have been confused as to the source and propagation of degenerative osteoarthritic changes. We know that surface injury to cartilage can occur from high-risk competitive sports and result in the development of osteoarthritis; the precise reasons as to this has eluded researchers in the field. Understanding the mechanobiology of the early stages of OA when micro-cracks start will be an important piece of the puzzle in the prevention of osteoarthritis.

Just this month, a group of researchers out of the University of Calgary, looked at the finer micro-structure of the cartilage. 1 They looked at crack propagation (micro-fracturing) of the cartilage to get a better understanding of the load and respective magnitude as it relates to the damage. Their objective included looking carefully at the local strain distribution of the cartilage nearby to the microcracks.

What did they do?

Cylindrical osteochondral punch plugs were harvested from pig knees and fixed to a custom design compression testing device. The cartilage thickness was measured at three different locations of the surface. To prevent dehydration, which can often occur in these testing environments and affect the results, they fully immersed the sample in a phosphate-buffered solution. The thickness of the cartilage was measured using light microscopy. Measures of strain were applied. To simulate the crack in the cartilage found in-vivo, vertical cuts were made in the cartilage at the most superficial part of the surface cartilage along with the middle zone.

What did they find out?

Axial strains were significantly more abundant at the damage zone compared to the non-damaged cartilage. This indicates that the ability of the cartilage to resist compression is less in the damaged or micro fractured cartilage, disrupting the biomechanics.

Crack Propagation Osteoarthritis


What can we take away from this study?

The drive to learn about osteoarthritis is essential. Billions of dollars are spent annually for a multitude of therapeutics, including joint replacement, injections, pharmaceuticals and manual therapy. By learning about how cracks propagate in the cartilage and, ultimately, how we prevent the development of osteoarthritis will be a great asset to the planet.

At Dynamic Disc Designs, we work to follow the research and work to bring that to the doctor-patient engagement process. Our latest modelling now includes a crack in the cartilage of the facet joint.