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.

Stuart McGill, ddd spinal models

In an online interview with Bill Morgan, President of Parker University, world-renowned spine researcher and scientist, Stuart McGill, uses dynamic disc models from Dynamic Disc Designs to explain lumbar disc herniations, extrusions, and the mechanisms for lumbar disc injuries and treatments.

When treating spinal injuries, McGill stresses the importance of recognizing that the cause of most disc extrusions and herniations is a combination of factors, occurring over time. The cumulative array of factors may present as an acute condition causing pain, but in most cases, the disruption has not been created by a single loading event.

McGill uses the analogy of cloth to explain how repetitive loading and movement fray the collagen fibers that cover the socket joints, eventually working a hole into the fibers by repetitive stress strains occurring in a back and forth motion.

“The disc is layer upon layer of collagen fibers held together with [a tightly woven lamination matrix]. If you keep moving the disc under load, the hydraulic pressure of the pressurized nucleus slowly starts to work its way through the delamination that forms because of the movement,” he says.

He explains that when the collagen is intact and supple, a person has full range-of-motion without danger of creating tears, but when the spine is stiff and has become adapted to bearing heavy loads, it is in danger of injury.

“The problem comes when you combine the two worlds and confuse the adaptation process,” he says.

“In a modern lifestyle, you might have a person who sits at a computer for eight or more hours in a flexion stressed position which—on its own—may not be that bad. But then they go to the gym for an hour every night and start lifting loads. They’re taking their spine through the range of motion, so cumulatively, the collagen is asked to move, but it’s also pressurized. The nucleus behind gets pressurized and slowly works its way through the delaminated collagen.”

Stuart McGill, Models

Stuart McGill and the many ddd models he uses.

McGill, Dynamic Disc Designs

Professor Stuart McGill and Dynamic Disc Designs endorsement.

Recreating Compression Loading, Disc Bulge, and Proper Thrust Line with our Dynamic Model

Using the disc model, McGill demonstrates how the gel inside the disc remains pressurized under compression, but in cases where the collagen has become delaminated, bending the spine under a load creates a disc bulge.

“This is exactly what we see on dynamic MRI,” he says, manipulating the disc model to demonstrate. “In the laboratory we would inject the nucleus with various radio-opaque markers. We would watch the migration as the bulge would come through. Touch a nerve root and now you would match where the disc bulges with the precise anatomic pathway. If you sit for 20 minutes slouched and your right toe goes on fire, we know it’s the right ring and that’s exactly where the disk bulge is.”

McGill stacks the disc model into a thrust line and squeezes the spine segment to show how proper alignment adapts the movement experience.

“The whole disc is experiencing movement, but there’s no pressure, and nothing comes out to touch the nerve root,” he says.

Empowering the Patient with Simple Posture and Stress Exercise

McGill says his insight is based upon years of experiments studying the exact mechanisms of spinal injury and pain. He recommends using improved posture and stress—lying on the stomach for five minutes with two fists under their chin—to help,” mitigate the dynamics of that very dynamic disc bulge.”

He says the immediate relief provided by this simple exercise can empower a patient with discogenic pain and help alleviate the potential psychological trauma of feeling hopeless at not understanding the source of, or how to mitigate, pain.

Facet Tropism - Disc Bulge

A study examining the relationship between facet joint angulation, joint tropism, and Degenerative Spondylolisthesis (DS) found a clinically significant link between DS and facet tropism, as well as observing facet tropism in non-DS disc levels of the study subjects. This supports the theory that tropism may pre-exist and contribute to the development of DS, rather than being a by-product of the condition.

 

What’s at Stake?

DS is a common condition affecting middle-aged and the elderly population—especially women. Frequently occurring at the L4-L5 spinal level, the condition has been associated with a number of potential causes, including facet joint orientation. Patients with DS may have more sagittal-oriented facet joints, which allows anterior gliding of their superior vertebra. When a patient’s left and right facet joints are asymmetrical by a minimum of 8 degrees, the condition is considered to be tropism. The authors of this study compared patients with DS with a control group of patients who had no DS to determine how facet joint angulation and/or the presence of facet tropism might play a role in the development of DS.

 

The Study

A retrospective radiographic study of 45 patients with single-level DS, presenting with lower back pain (LBP), leg pain with or without neurological effects, and neurogenic claudication compared the images of the subjects in Group A with a control group (B) of 45 non-DS patients surgically treated for disc prolapse or stenosis, matched in sex and age. Patients with previous spinal surgery or trauma, tumors, vertebrae or congenital anomalies, degenerative lumbar scoliosis, and isthmic spondylolisthesis, as well as those with flawed imaging, were excluded from the group.

MRI axial images of various disc levels were processed and analyzed with PACS software in order to calculate the facet joint angles. A difference of 8 degrees of angulation was termed facet tropism. An independent and case-blinded observer assessed the images of both groups, and an analysis was conducted as to the orientation of the facet joints at three levels in both groups.

Results

Group A was comprised of 15 male subjects and 30 female subjects between 38 and 79 years of age, with a mean age of 62.2. Of the 45 Group A patients, 8.8 percent (4/45) presented with DS, two of which (50%) had facet tropism at index level. All four of these subjects also presented with facet tropism at an adjacent distal level. A total of 37 patients (82.2 percent) showed DS in the L4-5 level, and of those patients, 14 (37.8 percent) also had facet tropism at index level. Eleven patients (29.7 percent) presented with tropism at adjacent proximal level, and 29.7 percent (11) showed the condition at adjacent distal level. Four subjects had DS at L5-S1 level, and all of thse patients had facet propism at index level. A single patient also had tropism at adjacent L4-5 level, as well.

Twenty of the 45 Group A patients (44.4 percent) demonstrated facet tropism at the level of DS. IN addition, 12 of the patients (26.6 percent) had it at a proximal  level to DS level, and 15 (33.3 percent) at level distal to the DS level. Nineteen of the subjects (42.2 percent) had it at a single level, 9 showed tropism at two levels, and 4 (8.8 percent) had it at all three of the levels examined. In all, 71.1 percent of the patients in Group A had facet tropism at one or more levels.

The numbers in Group B were considerably lower, with 2 patients showing facet tropism at L3-4, 5 at L4-5, and 2 at L5-S1. Five of the subjects had single-level tropism, and 2 had it at two levels. None of the Group B patients had tropism at all three levels. In all, only 15.5 percent of the Group B subjects had facet tropism.

Conclusion

The study confirms the association between facet joint tropism and DS. More notably, the observation of higher numbers of facet joint tropism at adjacent non-DS levels in the DS group suggests that facet tropism could contribute to the development of DS, rather than being a secondary symptom of the condition. Patients presenting with single level DS should be followed up closely to monitor adjacent spinal segments that could become symptomatic in the future.

 

 

 

 

 

ddd models, dynamic disc models

A systematic clinical literature review 1 found evidence that high intensity zones (HIZ) on MRI scans may indicate a potential risk factor in lower back pain (LBP). The review authors suggest further studies are needed to understand the relevance of lumbar biomarkers in imaging to properly diagnose and classify LBP as it relates to HIZ.

What’s at Stake?

Various lumbar phenotypes have been identified and studied in the past to determine their effects on patients suffering from LBP. MRI is a common LBP diagnostic tool used by practitioners treating patients with LBP, but its effectiveness in identifying the sources of LBP has been questioned by researchers over the years. For three decades, the debate over whether and how imaged biomarkers may relate to LBP has remained inconclusive. This extensive literature review was conducted to seek clarity on how HIZ in MRI may indicate a reliable diagnostic tool for clinicians treating patients with LBP.

The Review

A total of 756 studies were scanned for data relating to search terms that were indicative of their usefulness to the researchers involved in this review. Six studies—five comparison studies, and one cross-sectional population-based study—were ultimately chosen for their relevance, and their data was reviewed in the context of an association between HIZ and LBP. The literature chosen was published between 2000 and 2015 and involved studies of symptomatic subjects and asymptomatic controls between the ages of 21 to 50 years of age.

Results

Three of the comparative studies demonstrated a clinically-significant association between HIZ and LBP. In one study, over 32 percent of the patients with LBP exhibited HIZ in at least one disc. Of these patients, 5.3 percent showed multi-segmental HIZs, with 3.9 percent showing HIZs in the adjacent discs. Furthermore, 57.5 percent of the HIZs subjects had symptoms of LBP, while only .02 percent of the patients without HIZs were symptomatic. There was a correlation between higher LBP incidence and HIZs in the lower lumbar spine or with multiple HIZs, but these statistics were considered clinically-insignificant. In another study, 61 percent of patients with HIZs experienced LBP, compared to only 32 percent of those without HIZs. The median rate of HIZs was lower in subjects without LBP than in those who were symptomatic.

While the data studied in this review indicates a higher prevalence of LBP in patients with identifiable HIZs in imaging studies, other studies have found little-to-no evidence of this correlation, indicating the need for further studies and reviews on the nature of HIZs and LBP in symptomatic and asymptomatic patients.

Conclusion

This systematic literature review suggests an association between HIZs and LBP. However, the authors express the need for further study of the LBP pathology and HIZs morphology/topography as they relate to various spinal phenotypes to determine how variant biomarkers on MRI studies may help determine the existence and source of LBP in patients.

intensive patient education, pathoanatomy

This study 1 published in JAMA (Neurology), randomly selected 202 acute low back pain patients to compare pain education to non-pain education. The results demonstrated not much difference between the groups.

The Methods

Participants engaged with their common physician and in addition to this familiar interaction, each participant was then randomly partitioned into two groups. Each of these groups experienced, in addition to the advice and interaction of their physician, an additional two x hour sessions of either:

Group 1: Normal engagement with doctor PLUS intensive one on one patient education (delivered by clinical psychologist in pain management (M.K.N.) trained) for an additional 2 (1hr) sessions. This patient education was delivered based on Butler’s and Moseley’s work. 2

Group 2: Normal engagement with doctor PLUS placebo patient education (delivered by the same clinical psychologist) for an additional 2 (1hr) sessions. Participants in the placebo patient education group received no information, advice, or education about low back pain from the trial clinician. Participants were encouraged to talk about any topic that they desired.

The Results

Retention rates remained high for both groups at ninety percent. Intensive patient education was not more effective than placebo patient education at reducing pain intensity at the three months. There was a small effect of utilizing intensive at one week and at three months but not at six or twelve months.

 

Discussion

In this study, patient education was used through a psychological framework model rather than a biomechanical model. It is important to understand that this study does not mean that patient education is ineffective or as effective as a placebo. This patient education angle does not attempt to help patients understand the cause of their pain. This approach is more of a top-down psychological strategy of patient education. Methods to subclassify these acute low back pain patients into specific biomechanical categories and then, offer those patients specific education and movement strategies would be helpful to study as groups within the acute low back pain group. These sub-groups could then be compared to placebo.

 


At Dynamic Disc Designs, we believe that empowering patients with a greater sense of self-awareness on the probable mechanical cause of the acute low back pain can be helpful in the management. Initially, pain-reducing strategies through movement awareness of painful structures should be prompt and focus on reducing nociceptive inflammation for the patient. Following the acute phase of low back pain, professionals using our dynamic disc models can further promote the physical awareness of specific postures to help prevent the recurrence and avoid a progression of the condition. Our models allow the practitioner to explain patho-anatomy in a patient-friendly way that does not induce fear avoidance behaviours for the long term.  They also enable the practitioner to provide a realistic forecast of the temporal biological adaptation process within the degenerative cascade framework of natural ageing with a dynamic 3d model. In other words, our dynamic disc models assist the patient engagement process with the opportunity to bring up anatomy in a non-scary and empowering way. We look forward to more research on this topic.

 

 

3d modeling, endplate lesion

An October 2018 study compared MRI’s of 966 lower back pain (LBP) patients to introduce a simplified, reliable method of classification for common endplate lesions. The study also noted associations between endplate lesions and variables, including age, rate of disc degeneration, sex, and Modic changes. The researchers then demonstrated the new system’s reliability by repeated observational rating over a period of days, using outside raters evaluating a percentage of the total sample results. The demographic and physiological findings of the study were largely in agreement with previous IVD endplate lesion studies but also added novel findings that had not previously been published.

basivertebral nerve, bone marrow edema, modic changes

Modic vertebra model- midsagittal cut exposing the basivertebral nerve.

The Study

The subjects in the study were all LBP sufferers under the age of 70, excluding patients with a history of back surgery, spondylodiscitis, or vertebral fractures. Data including age and sex were collected on all patients, and images were scanned and evaluated by an experienced radiologist.

A scoring and classification system for the Lumbar IVD spaces was noted on the images, with the descriptions:

  • Normal—Physiological curvature of both endplates, without the detection of any visual lesions in any of the sagittal MRI IVD space slices.
  • Wavy/Irregular—Curvature in at least one of the endplates, without detectable IVD lesions.
  • Notched—The presence of at least one circular small or V-shaped lesion on an MRI saggital slice.
  • Schmort’s Node—Clearly evident vertebral endplate deep focal defect, where the endplate is rounded, with a smooth margin
  • Fracture—Thickened bone fragment at the edge of an endplate, or any evident fracture of the endplate with similarly-sized fragments

A sampling of the image data was also evaluated multiple times over a period of two days by independent raters to ensure observer reliability. To determine how often each type of endplate lesion appeared associated with disc degeneration and alterations of the MRI signals, subgroups of the study subjects were created, and comparisons were made based on age and sex. A scatter-plot chart was created to track Modic changes, and the relative percentages were calculated and identified against an established threshold.

 

Results

The findings indicated minimal association between patient age at the time of the scan and disc degeneration, as well as minimal Modic changes in older patients, as opposed to entire population studied. The most common types of endplate lesion observed were the “notched” and “Schmorl’s Node” type lesions, and both were more common in male patients than in females. Few of the patients studied had “Wavy/irregular” or “fracture” lesions, which occurred in nearly equal numbers of male and female subjects.

There was a strongly evident correlation between disc degeneration and endplate defects across all LBP subjects in the study. All lesion types increased in all IVD levels where disc degeneration was evident. There was a significant increase in “wavy/irregular” endplate types whenever severe disc degeneration was present. This can be considered a reliable marker for the process of extreme disc degeneration.

Signal alterations were found to be associated with endplate lesions, specifically in “notched,” “wavy/irregular,” and “Schmorl’s Node” endplates. There were nearly twice as many notches in Modic changes of types 1 or 2 corner signal alterations. Schmorl’s nodes showed even more evidence of association.

 

Discussion

Though this study was conducted with the intention of developing a reliable method of endplate defect classification in LBP patients and to find correlations in the distribution of LBP by analyzing a large population of subjects via MRI, previous studies have indicated a correlation between back pain and lesions—something this study did not specifically address.

The results of this study agreed with previous studies that indicated male LBP patients are more likely to have IVD lesions than female patients, though similar lesion-levels were observed in male and female patients who showed evidence of severe disc degeneration, as is found in Schmorl’s nodes and in those with disc fractures.

Most of the patients showed no evidence of endplate lesions on the lumbar MRIs. Of those who who did have lesions, most (18.7 %) experienced them only in a single IVD level, and males were more likely than females (20.7 % to 16.7 %) to show evidence of lesions. Progressively fewer subjects had lesions involving more IVD levels.

There was a very slight correlation between age and lesions in this and some previous studies. That correlation appears to be stronger in the female LBP population than in males—a new observation that has not been discussed in previous studies.

The association between endplate defects and disc degeneration was evident, especially where “wavy/irregular” endplates occurred, indicating severe degeneration of the discs. Signal alterations and endplate lesions also showed a positive correlation, specifically in “wavy/irregular,” “notched,” endplates. This association was significantly evident in Schmorl’s nodes.

 

arthritic changes, lumbar models, cervical models

Arthritic changes are very common. They are often related to a person’s pain with neck pain as one of the highest ranked common causes of disability. In this specific research article 1, the authors looked at the micro-details of neck synovial joints. With osteoarthritis known to be related to neck pain, they were looking to reveal higher anatomical detail and they were also curious about whether men or women have more of these problems.

With both neck and back pain being multifactorial (which may include both psychological and social aspects) degenerative changes within the synovial joints play a significant structural role with the development of spondylosis. This is a general term to describe a disorder of the musculoskeletal system with an emphasis on joint space narrowing, intervertebral disc height loss and frequent formation of bony spurs.

The architecture of the cervical facet joints is quite well known with most of the current knowledge around the smooth (or lack of smoothness) hyaline cartilage to allow the joint to receive and distribute loads in an efficient manner. However, there has not been much quantitative data revealing the anatomy under the hyaline cartilage designated as the subchondral bone. This bone under the cartilage (sub, meaning below and chondral, meaning cartilage) has been of recent interest as there exist nerves in this area that can cause pain. This is thought to be similar to the basivertebral nerve of the vertebral body. The innervation of the facet, however, has ascending fibres travelling through the posterior primary division which can be seen in this Medial Branch Dynamic Disc Model.

 

modeling hyaline cartilage, models

Hyaline Cartilage Modeling in our Professional and Academic LxH Dynamic Disc Models

basivertebral nerve lumbar model

Basivertebral nerve of a lumbar vertebra.

Previous research has shown that the thickness of the hyaline cartilage is .4mm in women and .5mm in men with the subchondral bone making up approximately 5% of the total cartilage thickness. It is also known that with increasing age the cartilage starts to flake off (called fibrillation) and researchers also coin the stripping of cartilage from the bone, denudation. This means being nude. A joint surface within a covering. Other terms used to describe the break down of the hyaline cartilage is erosion, fissuring and deformation. All in all, the terminology all mean that the hyaline is thinning.

arthritic changes, subchondral, joint, model

Subchondral thickening – arthritic changes

How did they do it?

These researchers looked at 72 recently deceased people and examined their joints. They used microscopes to look closely at the facet joints to help understand the pathogenesis of the arthritic changes.

When they observed the osteocartilaginous junction, the morphological changes included: flaking, splitting, eburnation, fissuring, blood vessel invasion and osteophytes. They looked at the length of the cartilage, the hyaline cartilage thickness, the calcified cartilage thickness and the subchondral bone thickness.

They found that males tended to have more severe degenerative changes described by flaking and severe fissures in the facet cartilage. Click To Tweet

Points of Key Interest

  • this was a study that looked at 1132 unique cervical spine facets from 72 humans
  • males were found to have more degenerative changes of the osteocartilaginous junction
  • the thickness of the calcified cartilage and subchondral bone increased with age whereas the hyaline cartilage decreased
  • the osteocartilaginous junction is particularly important in the pathogenesis of osteoarthritis in the cervical spine facet joints

 

At Dynamic Disc Designs, we work to bring research to the practitioner so when there is a teaching moment, Professionals are ready to explain pain triggers as they relate to a patients symptoms and movements. Empowering people about their own anatomy helps in the crafting of customized treatment plans for each unique pain patient. Explore our dynamic models and help a patient understand their arthritic changes and what that means to them.

spine pain, models

Ed Cambridge: “Our colleague Jerome Fryer created some models for us, and this is some of the work that has come out of our lab with you and Christian Balkovec about the dynamic changes we see after herniation. Where we have disc height loss at one level, creating hypermobility at the adjacent level. So here you can see, when you move the spine around there is a stiffening effect down in the lower joint and in the upper joint hypermobility. That’s what we see when an injury propagates from one joint to the next. The patient says, “Well, the pain used to be lower but now its starting to creep up my back a little bit.” “

Stuart McGill: “Fabulous. Another little take on that … By the way, these are all cast from real human specimens. So this is the real deal. Once again, Dynamic Disc Designs has been so clever in representing the biofidelity. We start to see how this disc has been damaged, and it’s quite lax as we move it around. So those micro-movements now are triggering pain just at that level. And this joint has normal stiffness, but then look what happens. Over time, the join changes because of the change in mechanics. The lax disc now cases a bit more arthritis in those facet joints, because they are now responsible for much more motion. So then, look what happens to the cascade. As the person now extends, look what happens. The joint that was hypermobile has now bound up, has no mobility because the facets have bound up and all the motion is now left at the previously stiffened joint. The polar opposite. And then you need some kind of mobility to pop those facet joints open again after they’ve been jammed.”

inflammatory mediators

The changing spine and the anatomy. Professional LxH Dynamic Disc Model

Stuart McGill:  “So, when you understand the cascade of change that happens at a joint, it might be kicked off with a little bit of a flattened disc, which puts more load in the facet joints, which causes a little bit of arthritic growth. In two years, the joint has changed and so have the pain patterns and the mechanics. So, it really does lend insight to allow us to understand the cascade of how the patient reports those changes and their pain changes over the years. And it better allows us to show them what to do to wind down the pain sensitivity. “