Degenerative disc disease (DDD) is very common and is not always related to pain. However, if a patient is experiencing back pain, it is more likely the patient does have DDD or is in the process of acquiring it. Our models help explain that DDD is often a process and often intertwined with aging and spinal pain conditions.

Degenerative disc disease (DDD) is at the roots of Dynamic Disc Designs (ddd). Learning and teaching the underlying mechanisms of pain and the strategies to relieve and live with this common condition is what we strive to do. Bringing the research to the forefront, in front of the patient and doctor with a dynamic teaching tool.

Disc Degeneration Model

Goal of the Study?

In this primary research article 1, the authors aim to establish an animal model that can be extrapolated to the complex mechanical load of a human intervertebral disc during bending and compression loading.  They hypothesized that a disc herniation could be gradually induced by static complex loading.

 

Why are they doing this study?

Disc bulges or protrusions often pre-exist in patients with acute back pain, suggesting that repeated compressive loads may gradually result in a herniated intervertebral disc.  To the author’s knowledge, this assumption has never been verified using animal models.

 

What was done?

Twenty research rats were randomly divided into four equal groups.  Group #1 was the control; the other 15 rats had an external device implanted in the coccygeal 8-10 vertebrae to bend the spine at a fixed angle.  Group #2 had sham surgery but no compression load, Groups #3 and #4 were subject to a compression load of 1.8 N (0.184 kilogram force) and 4.5 N (0.459 kilogram force) respectively.  After 14 days, an MRI was performed on all 20 rats and a Pfirrmann classification system was used to classify the disc images into 5 categories.  The rats were then euthanized and the C8-10 vertebral body was removed and the Norcross calcification system was used to evaluate the degeneration on a scale of 10 for no degeneration and 2 for severe degeneration.  The dissections were also tested for Gene Expression and various statistical tests were performed.

 

What did they find?

No statistical difference was found between the control group and the sham surgery group, so bending alone seemed to have little or no effect on disc degeneration.  There was a slight difference but it was not significant.  The MRI and histological scores for the intervertebral disc degeneration were significantly higher in the two loaded groups than the sham or no load surgery group.  Group #4, heavily loaded had significantly more disc degeneration than the lightly loaded group.   Both loaded groups had significantly more disorganization in the nucleus pulposus and annulus fibrosus from a histological perspective than the sham surgery group.

 

Why do these findings matter?

Even though the disc structure of rodent tails are biomechanically and compositionally similar to human lumbar there are significant differences.  As such, it is difficult to extrapolate this research to humans in a disc degeneration model comparison.  But if it can be extrapolated, it indicates that a static complex loaded can induce posterior intervertebral disc protrusion when combining bending and compression but not during bending alone.

 

At Dynamic Disc Designs, we believe it can be very helpful to show patients the mechanism of a disc injury to help empower a patient about prevention and the solution strategies to their problems. Our dynamic disc models demonstrate that bending alone does not cause disc herniation but will herniate when compression is combined with flexion.

Low back pain

Goal of the review?

In this paper, 1 the authors provide a research-based overview of the epidemiology, causes, and risk factors. They also describe the clinical presentation and diagnostic criteria, and treatment options for low back pain.

 

Overview

Epidemiology and Socioeconomic burden

The economic impact of lower back pain is widely significant, with estimates of £2.8 billion in the UK and $100 billion in the US. Almost two-thirds of the economic costs from lower back pain stem from indirect costs such as loss of productivity. One study done in 195 countries found low back pain the leading cause of productivity loss in 126 countries. 

Low back pain can be classified as mechanical, neuropathic or nociplastic. Studies have shown that the prevalence of neuropathic pain ranges from 16% and 55% in patients with chronic lower back pain. One systematic review illustrated the prevalence of low back pain to range from 11.9% – 23.3 %, increasing with age and most common in middle-aged to older women.

 

Pathogenesis

There is a multitude of factors and causes of lower back pain. These include disc degeneration, radicular (neuropathic) pain, facet arthropathy, myofascial pain, sacroiliac joint pain, spondyloarthropathies (ankylosing spondylitis and psoriatic arthritis), and nociplastic pain (non-specific low back pain).

Low back pain

Professional LxH Model and the Lumbar Spinal Stenosis Model — helping patients understand their source(s) of low back pain.

 

Brain change, behavioural and genetic factors

Low back pain can be caused by changes in the brain, such as alterations in blood flow and changes to white and grey matter in the brain. Behavioural factors can also play a role. Studies show the role that emotion and emotional experiences can have on low back pain. For example, negative expectations, depression, and anxiety have been shown to predict poor pain outcomes in patients. Finally, there are also genetic factors that contribute to low back pain. Research has illustrated that heritability contributed to 26% lifetime prevalence of low back pain, 36% for functional limitations and 25% to pain intensity.

 

Clinical presentation, diagnosis, and screening

Low back and leg pain can be a manifestation of intervertebral disc herniation. Often, this type of pain will resolve itself in a few weeks. However, some patients can have recurring pain for up to two years. 

A large percentage of back pain is non-specific and resolves without any formal diagnosis. However, most guidelines recommend that patients have a physical exam and that history is taken. Some patients may require a neurological exam or vascular-focused exams to differentiate different types of claudication. Routine imaging is not required for most lower back pain cases. However, CT scan, MRI, and x-ray can be useful depending on the case.

Different screening tools have been developed that assist in preventing and treating low back pain, identifying patients prone to chronic pain, and distinguishing neuropathic from non-neuropathic pain.

 

Prevention and Treatment

Research demonstrates that a combination of exercise, education and ergonomic changes are effective as prevention strategies for lower back pain. These behavioural, non-pharmacological approaches are also used as first-line treatment. This can include clarification-oriented and exposure-based interventions that can help patients self-manage their pain and pain behaviours. 

For patients whose pain persists, pharmacological and procedural options can be explored. The American College of Physicians Guidelines recommends that treatment begins with non-steroidal anti-inflammatory drugs (NSAIDs) and muscle relaxants, tramadol, or duloxetine as second-line treatment and opioids as the last choice. Due to the addictive potential and negative side effects, opioid treatment is not recommended for most patients. 

There are also non-pharmacological interventions for low back pain. Steroid injections in the foramen, between the vertebrae, and in the sacroiliac joints have positive therapeutic effects. Other interventions such as facet joint blocks and radiofrequency are used but have mixed evidence supporting them. Spinal cord stimulation has shown positive outcomes and can be cost-effective, depending on the patient. 

When other interventions have not been successful, surgery may be an option for some patients. Research shows that for herniated nucleus pulposus, surgery can provide relief for a period but does not result in long-term benefits. For patients with lumbar spinal stenosis, decompression surgery can provide substantial improvement compared to a traditional approach.

 

Conclusions

Low back pain is globally prevalent and increasing as lifestyles become more sedentary. Lower back pain is a complex condition with various factors; therefore, diagnosis and treatment can be challenging. Existing research provides important evidence that can be used to develop inter-disciplinary and multimodal approaches to treatment and diagnosis. 

Pain Syndromes

Goal of the Study?

In this study, 1, the authors have developed a framework to differentiate Parkinson’s Disease (PD) pain from non-PD-related pain and classify PD-related pain into 3 groups based on already validated mechanistic pain descriptors – nociceptive, neuropathic and nociplastic. 

 

Why are they doing this study?

In Parkinson’s disease (PD), about 20% of patients experience chronic pain at diagnosis. This number climbs to 80% during the course of the disease. PD pain has been divided into three categories: de novo pain related to disease onset and symptoms (PD-related); previous chronic pain aggravated by the disease or treatment (PD-indirectly-related); pain that is neither caused nor aggravated by the disease (PD-unrelated). Moreover, pain is considered PD-related when one of the following applies: when occurring along with the first motor symptoms, when occurring/aggravated during the OFF stage of the disease, when occurring at the same time with choreatic dyskinesia or when improved by dopamine treatment. However, these categories have not been validated or tested, making diagnosing and treating pain in PD. In response to this need, the authors develop a classification system to define and distinguish PD-related pain from non-PD-related pain.

 

What was done?

The authors used an international, cross-sectional, multicenter study. They recruited 159 non-demented PD patients and 37 healthy controls across 4 centers. Using the mechanistic pain descriptors (nociceptive, neuropathic and nociplastic), the authors developed a PD pain classification system (PD-PCS) by including classic pain-related situations of PD into each category. The severity of PD-related pain syndromes was scored by ratings of intensity, frequency and interference with daily living activities. Finally, they did an analysis and validation of their scale.

 

What did they find?

This study provides a unifying system for pain in PD that differentiates between PD and non-PD pain and outlines a treatment-based and mechanistic classification system for PD-related pain. Using this system, the authors found that 77% of patients experienced PD-related pain, with 15% suffering more than one syndrome at the same time. PD-related pain with nociceptive, neuropathic or nociplastic components was diagnosed in 55%, 16% and 22% of participants, respectively. Mixed pain syndromes were mostly found in nociceptive pain combined with nociplastic (12.7%) or neuropathic (9.6%). Pain unrelated to PD was found in 22% of participants, versus only 5% of controls. 

Concerning the PD-PCS, the authors found that pain severity scores significantly correlated with commonly used questionnaires such as the pains’ Brief pain Inventory and McGill Pain questionnaire. They did not find that the PD-PCS scores correlated with a motor score.

Finally, they suggest that the three pain types identified by the PD-PCS are different pain syndromes and reflect different mechanistic backgrounds and, potentially, different treatment approaches.  For example, they found that patients with higher nociceptive pain scores had worse quality of life scores, but this was not found for patients with nociplastic pain. 

 

Why do these findings matter?

Better classification of pain in PD will ensure that PD patients’ pain is treated more effectively and timely, ultimately contributing to better outcomes.

 

Facet angle

Goal of the Study? 

In this study 1 the authors use MRI to measure changes in the facet angles of the lumbar spine and analyze the relationship between angle changes and the herniated lumbar intervertebral disc. 

 

Why are they doing this study?

The incidence of lower back pain (LBP) is prevalent in today’s society and can place an enormous burden on individuals and health systems. There are many causes of LBP, including lumbar facet joint (LFJ) degeneration, lumbar disc herniation (LDH), compression of nerve roots, and others. There is currently little understanding of the role of lumbar facet joint angle changes and lumbar disc herniation play in LBP. The authors comment that there is a lack of knowledge on whether the structural abnormality of the spine resulting from LFJ degeneration causes the abnormal force of the lumbar intervertebral disc herniation. Additionally, there is a need to understand whether lumbar facet joint angle changes are common in patients with lumbar disc herniation.

 

Professional LxH Model (L4-5) with asymmetric facet angles

 

What was done?

First, the authors review both direct and indirect signs of lumbar disc herniation as seen on MRI. They state that MRI provides an advantage to obtain horizontal and sagittal three-dimensional scanning of the spinal cord, subarachnoid space, vertebral body and intervertebral discs. They review the various signs of the nucleus pulposus, schmorl nodules, lumbar dural sac, lumbar spinal cord and nerve root compression.

The authors used cross-sectional images of the MRI to measure angles of the articular processes on both sides. They included 500 cases of patients with a clinical diagnosis of lumbar disc herniation and concurrent lumbar disc MRI examination. This included 227 males and 273 females with an average age of 41. This was broken down into 137 cases in the central LDH group, 140 cases in the left paralateral LDH group, 127 cases in the right-side LDH group and 75 cases in the control group. The cases were based on those who met the diagnostic criteria over 18 and relevant imaging and clinical data. Statistical software was used for statistical analysis.

 

What did they find?

The authors found no statistically significant relationship between age, gender, height and weight of the groups and LDH. They found no statistically significant relationship between MRI and CT measurements of the facet joint angle. They argue a correlation between the changes illustrated in MRI images of lumbar disc herniation and the TCM syndromes of lumbar intervertebral disc herniation. They found that the L4/5 and L5/S1 segments of the lesion in the central LDH group and the left paralateral LDH and right-side LDH were all significantly different from the control group.  Facet joint asymmetry is closely related to lateral lumbar disc herniation. However, the asymmetry of the facet joints is not related to the central lumbar disc herniation. They argue that MRI has a high sensitivity concerning measuring angles of the facet joint and changes to those angles and how they correlate with herniated discs. 

 

Why do these findings matter?

Understanding the relationship between lumbar facet joint angle changes and lumbar disc herniation is useful for preventing and treating LBP

loading

Goal of the Study?

In this preliminary study, 1 the authors compared the effects of loading compression and traction on lumbar disc measurements, particularly the magnitude and distribution pattern of fluid within lumbar discs, in relation to intervertebral disc degeneration.

 

Why are they doing this study?

Intervertebral disc degeneration (IVDD) is associated with many biochemical and morphological changes in the disc that contribute to degeneration and negatively impact normal function. With degeneration, there are changes to the amount of fluid and the distribution pattern of this fluid within the disc. The authors argue that this may provide unique biomarkers that can help with diagnosing and classifying degeneration. The authors hypothesize that using T2- weighted MR images will enable better insight into disc degeneration. It only changes in response to variations in fluid distribution and these potential degeneration biomarkers. 

 

What was done?

A total of 35 volunteers between the ages of 18-65 were recruited: 20 with and 15 without low back pain (LBP). Using a custom MRI compatible loading table, the participants spent 20 minutes in the supine, unloaded position; then they spent 20 minutes loaded in axial compression and then 20 minutes with axial traction. A compressive load equal to 50% of each subjects’ body weight was applied to simulate loading and traction. For lumbar discs, the height, angle, width, mean-T2 and T2 weighted centroid (T2WC) locations were calculated. Disc degeneration was measured using the 5-point scale by Pfirrmann et al.

 

What did they find?

Most of the effect size (ES) differences the authors found in response to loading were seen from compression to traction. They observed small but statistically significant changes with an inferior and posterior shift in L4-5 (ES: 0.4, 0.14) and L5-S1 (ES: 0.25, 0.33) T2 weighted centroid. More degeneration was associated with larger anterior displacement and more superior displacement of the disc T2WC. Moreover, degeneration was not associated with changes in disc width, but with greater degeneration, there were larger decreases in an extension of segmental angles.

From unloaded to compression, they found statistically significant small posterior shifts for the disc T2WC at the L1-2 level (ES: 0.39). They also saw an increase in L5-S1 width (ES: 0.22), an anterior shift in L1-2 T2WC (ES: 0.39), and L3-4 (mean 2.1˚) and L4-5 (1.8˚) extension angle. Additionally, with more degeneration, there were larger inferior movements of the disc T2WC, but not changes in disc width. 

Overall, their findings on compression to traction demonstrated the most significant findings in the lower lumbar levels. They also found a magnitude difference associated with the severity of disc degeneration. This supported their hypothesis that fluid distribution-related measurements illustrating the effects of degeneration and lumbar disc loading.

 

Why do these findings matter?

Biomarkers can help to illustrate how the lumbar spine responds to different loading conditions and can be used to monitor degenerative changes in the lumbar spine.

 


At Dynamic Disc Designs, we appreciate the dynamics of the discs and how professionals can communicate these small changes to patients as it relates to their dynamic symptoms and the solutions of back pain.

GAG content

Goal of the Study?

In this study 1, the authors’ goal was to assess the GAG contents of lumbar IVDs in disorders of the spine, including non-specific lower back pain (nsLBP) and radiculopathy, against asymptomatic volunteers to determine the potential influence of IVD protrusions on the GAG contents of adjacent IVDs.

 

Why are they doing this study?

Low back pain (LBP) is a common health burden that has significant implications for individuals and society. Most LBP is non-specific (nsLBP) and without a known cause. One potential factor contributing to nsLBP is lumbar degenerative disk disease (LDDD). A common structural disorder that leads to LBP is lumbar IVD extrusion with radiculopathy. While MRI for diagnosis of LBP is controversial, it is the most commonly used technique for looking at the morphological changes in LDDD, such as IVD dehydration and loss of IVD height. However, to detect early structural changes to cartilage, the use of the non-invasive compositional MRI technique GAG Chemical Exchange Saturation Transfer (gagCEST) is preferred. Existing research has demonstrated how gagCEST images can help to differentiate degenerative and non-degenerative IVDs based on their respective GAG contents. To that end, the authors hypothesized that the GAG contents in patients with nsLBP and radiculopathy are significantly lower than in asymptomatic volunteers and that the GAG content of lumbar IVDs adjacent to extruded IVDs is markedly lower than that of non-adjacent IVDs.

 

What was done?

In total, they recruited 18 patients with radiculopathy and IVD extrusion, 16 age-matched patients with chronic nsLBP and 20 age-matched volunteers. All of these participants underwent morphologic and compositional gagCEST MRI. Patients were assessed by an orthopedic surgeon and underwent a neurologic exam, with a focus on radicular pain, distal sensation and muscle strength. All participants’ lumbar IVDs were graded individually and independently using the Pfirrmann classification (non-degeneration) grades 1 and 2; degenerative IVDs (grades 3-5). Statistical software was used to determine statistical significance.

 

What did they find?

Patients with radiculopathy demonstrated IVD extrusions at the IVD segments L4/5 and L5/S1, compared to patients with nsLBP or asymptomatic volunteers who showed none. No differences in Pfirrmann grades were found between patients with nsLBP and patients with radiculopathy and patients with radiculopathy and asymptomatic volunteers. Regarding gagCEST values, the authors found that patients with nsLBP demonstrated lower gagCEST values in their IVDs than those of volunteers, with 1.3% and 1.9%, respectively. However, there were no differences in gagCEST values between patients with radiculopathy and asymptomatic volunteers or female and male participants. Finally, in patients with radiculopathy, IVDs directly adjacent to IVD extrusions showed lower gagCEST values than distant IVDs. The authors argue that GAG depletion in nsLBP and IVDs adjacent to extrusions in radiculopathy demonstrates close interrelatedness between clinical pathology and the compositional and structural changes to IVDs in the degeneration of the lumbar spine. 

 

Why do these findings matter?

Non-invasive gagCEST imaging provides potential diagnostic value to detect early changes to tissue composition and pre-morphological IVD degeneration. It serves to differentiate patterns of IVD degeneration in disorders of the lumbar spine. Early detection can lead to better diagnosis, care and treatment of lumbar spine disorders in patients.

Dynamic Sitting Exercise

Goal of the Study?

The objective of this study [1. An Evaluation of an Innovative Exercise to Relieve Chronic Low Back Pain in Sedentary Workers] was to examine the effectiveness of a unique supported dynamic lumbar extension with the abdominal drawing-in maneuver (ADIM) technique on stature change, deep abdominal muscle activity, trunk muscle fatigue and pain intensity during prolonged sitting in chronic low back pain (CLBP) participants.

 

Why are they doing this study?

Low back pain (LBP) is a global issue among the working population. In Thailand, where this study is based, the prevalence of LBP across various occupations is approximately 83%, and 60% of workers in call centers have reported that their LBP is aggravated by sitting during the workday. 

Previous research has demonstrated that continuous sitting results in trunk muscles’ contraction, causing muscle fatigue and reducing muscular support to the spine. This increases stress on ligaments and intervertebral discs, ultimately leading to LBP. Existing research, such as that by lead author Jerome Fryer (the CEO of Dynamic Disc Designs Corp.) et al. (2010), has demonstrated the value of the dynamic sitting exercise on restoring disc height. Moreover, the ADIM technique has been shown to be effective in reducing the spinal lumbar load in patients with chronic LBP. 

 

What was done?

This is the first study investigating the combined use of a supported lumbar extension with the ADIM technique on stature recovery in CLBP patients.

They recruited 30 patients (15 males and 15 females) between the ages of 20-39 years old. All participants included had CLBP lasting more than 3 months, had low to moderate pain levels and reported sitting for at least 2 hours at work.

The participants were randomly assigned to one of two groups: 1) control – sitting without exercise; 2) sitting with supported dynamic lumbar extension with the ADIM technique. The control group sat for a 41-minute testing period. The intervention group sat in a neutral posture for 27 seconds; at the 28th second, they straightened their lower back and drew in their lower abdomen and extend their lumbar spine with their upper limbs supported to transfer the spinal load to the upper limbs, with their chest up slightly and chin in for 5 seconds. Participants were then repositioned to a neutral position and relaxed their lower abdomen for 3 seconds. This was completed 3 times over the 41-minute sitting period.

 

What did they find?

This study found that a dynamic lumbar extension with the ADIM technique protected from the detrimental effects on stature change and deep trunk muscle fatigue that can result from prolonged sitting. They found the intervention significantly reduced stature loss compared to the control group. Additionally, they found that this combined approach prevented an increase in pain intensity during prolonged sitting in people with CLBP. 

 

Limitations?

This study has several limitations, including the use of young participants, setting the study in a laboratory rather than the workplace, self-reported data, lack of consensus on body positioning, and limiting the findings to immediate effects rather than long-term outcomes.

 

Why do these findings matter?

Clinicians can implement this intervention for patients who sit for long periods of time as a way to prevent LBP problems.