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Audible Noises and Synovial Joints

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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Types of Lumbar Models

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.

Dynamic Cervical Spine

Central herniation under load

Many clinical symptoms are a result of a dynamic cervical spine.

In a recent article titled :

Dynamic Changes of the Ligamentum Flavum in the Cervical Spine Assessed with Kinetic Magnetic Resonance Imaging

Authors looked at quantifying ligamentum flavum thickening with dynamic motion using kinetic MRI. They found the ligamentum flavum increases thickness with extension which can be an important clinical symptom with patient  history positioning in the evaluation of  a diagnosis.

Many spinal complaints are a result of certain cervical spinal movements. Patients explain pain can be greater in extension like that of overhead activities. Very often this can be teased out in the history taking and often able to be reproduced during the physical exam. Once these findings are supported, education is important in assisting a patient to minimize aggravation of symptoms through accurate spinal modeling. When patients see they believe! Patient compliance is often the weak link in obtaining better outcomes.

Dynamic Disc Designs is committed to providing  physicians with accurate spine modeling. Our dedication to patient spine education in a dynamic and realistic way empowers the doctor to harness the best possible outcomes. Visit our roster of cervical models to help educate patients in describing directional preference.

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Clinical Spinal Complaints are often Diurnal

Disc Bulge Model

Many clinical spinal complaints are correlated to diurnal (which means the day-night cycle) influences.

It is well known that the intervertebral discs lose and regain hydraulic fluid over the course of this cycle. Specifically, we know water compresses out of the discs and lying down will re-imbibe the loss. Research has shown approximately 16% of change to the lower lumbar discs. Often, patients will have symptoms related to this as some complain of pain in the mornings when the discs are full of fluid and stretch open the annular tears in the discs.  This especially occurs under first get-up and when trying to put socks on. A dynamic intervertebral disc model can help the practitioner in the discussion of these pain generators with a dynamic disc to show height loss.

In the Journal of Biomechanics, other research is now looking at other cartilage in the body and specifically, the knee, to see if there are changes from loading and unloading environments.  The intervertebral discs in the spine carry the same cartilage as the knee (hyaline cartilage) and therefore this knee research relates to the spine.

Dynamic Disc Designs models are helpful is education of diurnal influences from a clinical level.  For example, when the disc squishes down the hyaline cartilage of the facets at the same spinal level can rub and irritate subchondral nerves. This is a common complaint of the spine and our models help the practitioner bridge the research knowledge to the patient in a platform to motivate changes that will improve outcomes.  Explore our roster and take control of your spinal education in a dynamic platform–just like the research shows.

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Types of Cervical Models

Cervical Models

When educating on the intricate mechanisms of cervical vertebrae and intervertebral disc, visual demonstration is often proven to be the most effective technique.

At Dynamic Disc Designs, we are committed to providing the best spine models in the world to assist in this educational process. To that end, our line of cervical models are realistic and anatomically accurate educational tools highlighting different conditions in the upper human spine. These are influential tools for educating your patients whether you are a chiropractor, surgeon, physiotherapist, osteopath, or lawyer.

We offer three different cervical models to ensure that you and your patients are provided the best educational tools for cervical conditions. The cervical degenerated herniating spine showcases a reduced disc height caused by degeneration often resulting in stenosis. The cervical spinal stenosis model displays a multi-level cervical spine with a paracentral disc bulge on one side of the model. Also available is the professional cervical herniating disc model, which is also  real in cervical size and is a matching specimen to our professional LxH lumbar model. This model features a two-part intervertebral disc with six degrees of natural motion and post-lateral nuclear migration upon manual compression.

You can count on Dynamic Disc Designs to provide you with the most realistic and accurate spinal models. All models are constructed with  identical copies of natural specimens and feature trademarked two-part intervertebral discs – allowing you to accurately and dynamically demonstrate, by hand, the motion and progressive nature of different spinal conditions.

Interested in learning more?

Give us a call at 250-751-0897.

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Mechanical Upregulation

Lumbar Disc Herniation Model - fibrous annulus

Mechanical upregulation is a popular topic. We know that intervertebral cells respond to physical stimuli.

But at what mechanical frequency is the key.  Important information has been revealed in this foundational research showing how specific vibrations upregulate disc cells. Forces of varying magnitudes and durations have been used clinically in the conservative approach to spine pain and related joints of the spine. Chiropractors have used low amplitude high velocity adjustments (HVLAT) for over a century in the management of spine pain. Traction has also been utilized by physical therapists.

More recently, mechanical decompression (which uses an intermittent traction strategy) has shown effect. All strategies use mechanical force in the attempt to provide a therapeutic outcome. One, uses a very short frequency and the other use longer frequencies. And arguably, each strategy has its place but it is the patient selection that is the challenging clinical question.  That is, which patient responds best to HVLAT and which patient responds best to traction, or decompression? This new research pushes us a little closer to the truth.

Dynamic Disc Designs offers models that move–opening clinical discussions about selection criteria for specific treatment options for patients. If you want to learn more about these models to help with research questions and patient education.

Call us at 250-751-0897


Lumbar Discogenic Pain

Subchondral Scelrosis

Lumbar discogenic pain is common. Nikolai Bogduk, MD presents a State-of-the Art review on discogenic pain.

He concludes : “Discogenic pain can occur and can be diagnosed if strict operational criteria are used….”  It is refreshing to see true, foundational research.

Dynamic Disc Designs offers lumbar models to help patient education to improve outcomes.When patients understand the basic difference between anterior and posterior structures and their relationship to flexion and extension, patients can avoid aggravating spinal movements to minimize deleterious movements to help reduce inflammation.

Knowledge is power both to the doctor and patient.

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