Dr. Jerome Fryer (CEO of Dynamic Disc Designs Corp):

“Hello everyone. Dr. Jerome Fryer here of Dynamic Disc Designs. I just want to reach out to those customers that have one of my models. There’s been a lot of talk lately on social media regarding how models can be scary. I don’t know how they’re scary. Models are not scary. It really depends on the user and these models are not intended to scare anybody. It’s to teach them their own anatomy, so they can improve their posture and biomechanics to relieve their symptoms. It’s a team player. It’s like a car. You can go out there ram into people or you can drive defensively and respectfully. Anyway, so one thing that’s important when you’re using the model is to relay realistic biomechanics  and use the model in a way that simulates real-time and load.

You want to use it in a way that actually represents the actual tissue. You can talk about all sorts of things, but you can talk about disc height changes as the disc over the course of the day loses a percentage of its height. You can talk about normal loading patterns of the disc as it relates the associated nerves. But, what I would encourage is just to use real-time forces. For example if someone goes to sit down, they change their lumbar angle and they compress their disc. When they sit for a period of time, the disc actually loses further height. You want to show the subtle endplate angle changes as it relates to the facet joint for example, or in the suspected case of disc herniation, you can actually create a disc herniation.

Single-Level Disc Herniation

Model of Single-Level Disc Herniation.

One example is the changing fluid expression over the course of the day. This is an important little graph to help patients understand how first thing in the morning you’ll actually lose their height very quickly in the disc height, so the facets will actually approximate with the changing intradiscal pressure, and then over the course of the day the disc height will slowly reduce. Some people talk about around 4:00 or 5:00 in the evening as the day progresses, my symptoms become pronounced. Then also with first lie down too. You can see there’s a quick change in disc height. Anyways, I just wanted to share with you that it’s how you use the model and you want to use it in ways that are realistic with regards to movement.”




Patient Education - Cervical Models

Dynamic cervical spine models have been static in the past.

Research demonstrates MRI can show problems like disc bulge and disc herniation even though patients do not have symptoms. Interestingly, there has been a shift in clinical thinking that many MRIs are ordered unnecessarily and can lead to unnecessary surgery.

What we are beginning to learn is that specific MRI imaging may be better at looking at pain generators in the cervical spine. In a recent publication in the Journal of Orthopedic Science, these researchers looked at T2 mapping as a way to indicate whether the discs are symptomatic or not.

This has always been the problem with MRI imaging. Most pain generators are dynamic in nature. That is, most of a patient’s pain comes with moving in certain direction or moving in a certain direction for an extended period of time. To date, the only way we were to determine whether the interevertebral disc is painful, is use of the gold standard discogram.

This is an invasive procedure that pokes the disc, with a needle, and over inflates it, like a tire, to see how much pain can be generated in the patient. The problem with this procedure is that if you poke a disc it begins to degenerate. Researchers use this model to study degeneration.

T2 mapping MRI is non-invasive–at least we have no evidence, yet, to suggest it is. And T2 mapping is also suggestive that it is looking at the water content of the intervertebral discs.

The future of understanding pain generators of the spine will be a the careful analysis of disc height loss, water content of the nucleus pulposus, and dynamic MRI imaging.

An accurate and dynamic cervical spine model can help explain load related pain generators like disc bulging and disc herniation. Treatments targeting the restoration of disc heights and the lordotic curve will lead the way in decades to come. Dynamic Disc Designs produces models to encourage research and education.

Synovial fold, tag, meniscoid

Synovial Fold Release and Joint Cracking : a New Hypothesis for the Sound Generator has been created

In 2013, much work on simulating the synovial joint was conducted and led to in-vitro testing using ddd models to demonstrate the sound.
The mechanism of a cracking joint sound was produced with two factors in place.  The precursory details required to create the environment to produce the sound of an audible release were:

polished simulated cartilage surface and elastomeric simulated synovial fold. No fluid or gas was required.
  1. Negative pressure was required to induce the noise
  2. Negative pressure was required to re-produce the noise
  3. Different sound characteristics (differing tones) were observed when different material properties were used for the fold—both in size, shape and intrinsic qualities (ie., elongation, tensile strength and durometer).
Points to support this suction release phenomenon in a vitro testing environment.
  1. The noise generated from a suction cup release is not a gas rushing into the negative space but the elastic recoil of the cup material itself.
  2. This noise is generated both without fluid (in air) and in fluid (in water). This provides support that the sound is irrespective of the environment and more related to the elastic properties of the simulated fold.
Other points.
  1. Audible releases have different sound signatures. Not all events are identical.
  2. Audible releases of differing synovial joints make different sounds. For example, a 5th MCP joint makes a different sound when distracted when compared to the 1st MCP. This is believed to be due to the shape of the fold/hyaline interface.

Clinical translation? Once we begin to identify the process of the noise generator, this will help lead us to better understand the pressures in and around the cartilage to improve mechanobiological therapies.

Core Muscles of Spine

Understanding core exercises and why they can work for many mechanical low back pain suffers may not be such a mystery.

At Dynamic Disc Designs we believe that the answers may not be as complicated as thought. In a publication titled, ” A Meta-Analysis of Core Stability Exercise versus General Exercise for Chronic Low Back Pain  ” the authors looked at RCT studies and compared regular exercise to core stabilization exercises in short term and long term outcomes of low back pain. They found a significant difference with the core stabilization for the short term but not so much for the long term outcomes.

What defines a core exercise? What is the core? And what is actually occurring in the spine during the core exercises? These are questions that are just starting to be asked. Some believe that core exercises have no scientific backing. You can read more here.

At Dynamic Disc Designs we believe that the true core of the spine is the nucleus pulposus. Core stabilization exercises often are done recumbent, and often works to brace the lumbar spine to facilitate nuclear intradiscal centralization, decreasing sensory afferent stimulation to free nerve endings in the disc. This often stabilizes the facet joints which is also thought to be a pain generator as well.

Dynamic Disc Designs manufactures models to help in the discussion of pain generators and strategies to improve the understanding of positive (and negative) clinical outcomes.

Audible articular release

Audible articular release sounds are very common with spinal manipulation.

There are still many people afraid of the sound and prevent them from trying spinal manipulation as a treatment for back or neck pain. To improve the explanation of this common procedure, Dr. Jerome Fryer, chief innovations officer at Dynamic Disc Designs Corp., has developed an audible articular release model ( spinal model ) that emits and audible “snap” when the facets are manually gapped as as in the actual procedure. This model has brand new features to help the practitioner explain precisely the procedure of spinal manipulation among other reasons as to why this type of procedure would be helpful.

Details include:

  • life-size L4 and L5 vertebrae connected by a flexible 2-part disc including a nucleus pulposus and annulus fibrosus, herniating nucleus under load
  • Synovial fold (noise generator)
  • Palpable polished hyaline cartilage on three of the four facets to allow the patient to touch what healthy cartilage should feel like
  • One facet has a roughened surface to simulate degradation of cartilage with a fractured surface and early degenerative sharp ostephyte growth to allow patients to understand clearly the early break down of cartilage in the osteoarthritis pathway
  • A signature dynamic disc to show the relationship of dynamic disc height loss and facet joint
  • an optional cauda equina

Dynamic Disc Designs flexible spine models are becoming the standard in spine education. Explore and find which model can help you the most with your education to improve clinical outcomes.

Synovial Joints, Synovial Fold

The classic “pop” or “snap” or audible noises associated with a synovial joint distraction is a curious sound.

There seems to be a generalized consensus that the structure responsible for the noise is a gas bubble. For a review you can read here and find out that we don’t really know where the sound is coming from.

Dr. Jerome Fryer (Chief Innovation Officer at Dynamic Disc Designs Corp.) believes that the sound is being emitted from the elastic recoil of the synovial fold (meniscoid, synovial tag) rather than the bubble.

As you can see above, the synovial tag can act like a suction cup. As each facet cartilage pulls away from each other, the synovial tag is drawn in either direction and recoils back into original position after it reaches its elongation end range. To understand the mechanics of action, you will need understand how a suction cup works….read here.

As a suction cup is pressed against a surface, air is pushed out. As the cup is pulled away, the now negative pressure under the the cup is similar to the negative pressure found in a healthy synovial joint (approx -3mmHg). When the suction cup is pulled from the surface, the surrounding atmospheric pressure pushes the cup to the surface until the cup reaches its elastic end point. At this point, there is an elastic recoil of the cup and it snaps back into its original shape and the atmospheric pressure surrounding the cup is equilibrated.

We know that a gas bubble presents itself after the “pop” event of distracting a joint. But there has been no definitive research that actually proves that the sound generator is the bubble. One of the references is 27 years old now and used phonoarthrography. In this 1986 study, Meal and Scott saw two sounds with the pop from a synovial joint.  In Dr. Fryer’s opinion, if the sound was coming from a bubble, we should have seen one sound, not two.  Their two sounds could be explained with this new hypothesis of  the synovial fold being the noise generator. This anatomy is not a point source but rather a ring of tissue able to generate two sounds from a single microphone, which is what these researchers used in their methods.

As we begin to unravel the precise definitions of audible joint sounds, Dr. Fryer’s  hope is we become better diagnosticians for synovial joints. And as a result of his new hypothesis, research is now moving forward with the University of Alberta using MRI.

(March 29, 2014) As the ongoing investigation of this hypothesis develops, Dr. Fryer decided to write a brief hypothesis article on this topic. This manuscript was submitted to Chiropractic and Manual Therapies on March 2, 2014. The result was a rejection. A revision was then submitted to JCCA on March 18, 2014. A rejection was the initial result and the Editor suggested a resubmission as a commentary. Jerome Fryer decided to upload the hypothesis manuscript.  If you want to read more, click Is the sound of manipulation from the synovial fold?

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Modeling by Dynamic Disc Designs Corp.

Our lumbar models will help you educate your patients or clients, allow you to accurately articulate what the patient’s body is experiencing, and explain best practices to alleviate their pain.

Lower back pain is a common complaint among patients – 8 in 10 people experience back pain at some point in their life. Recognizing that such pain can vary considerably from case to case, Dynamic Disc Designs have developed 16 different models to showcase the different conditions and reactions of the lumbar spine.

Our best sellers are the Professional LxH Herniating Disc Model and Academic LxH Herniating Disc Model. These two models include a herniating nucleus pulposus, transparent L4, opaque L5, and a realistic 2-part disc with 6 degrees of freedom and manual compressions. These are great tools for educating your patients on discogenic pain, chronic pain, nuclear shifting dynamics or the progressive nature of disc herniation and early forms of DDD.

Our other Dynamic Disc Design models can be used to further demonstrate dynamic and functional stenosis with degenerative disc pathologies like thickened ligaments — narrowing of the spinal canal. Instability models can also help in the education of pain generators with a spondylolisthesis option for our Professional LxH model.

Lumbar Models - Dynamic Disc Designs

Whatever your spinal educational needs are you can count on Dynamic Disc Designs to provide you dynamic intervertebral disc models with biofidelic accuracy. All models are constructed as identical copies of natural specimens and feature trademarked two-part intervertebral discs – allowing you to dynamically demonstrate, by hand, the motion and realistic nature of different spinal conditions.

Interested in learning more?

Give us a call at 250-751-0897.