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Disentangling ‘sciatica’ to understand and characterize somatosensory profiles and potential pain mechanisms

radicularDynamic Disc Designs Corp.

Goal of the Study?

In this case-controlled study from the Scandinavian Journal of Pain1 the authors’ goal was to investigate if patients diagnosed with only lumbar radicular pain have different pain experiences and somatosensory profiles from those diagnosed with combined lumbar radicular pain and radiculopathy.   

 

Why are they doing this study?

The prevalence of “sciatica”, commonly known as pain radiating from the lower back into the leg, varies significantly between studies and investigated sample populations.  Evidence for the benefit of conservative management is inconclusive with some cohorts responding to treatment and others not. Understanding clinical care pathways and treatment outcomes are muddied, with a variety of challenges to the interpretation of conditions and appropriate care.  This study is an attempt to reduce one of these confounding challenges by comparing the differences of somatosensory profiles of two patient groups.

radicular

What was done?

Comprehensive Quantitative Sensory Testing (QST) using a series of tools were applied to 26 patients, eight of which had only radicular pain and the other 16 had radiculopathy co-morbidity.  These measurement tools included;

A neurosurgeon, blinded to the patient’s clinical presentation reviewed lumbar MRI imaging and graded the degree of nerve root compression according to Pfirrmann’s system.  Nerve root compression was found in 12 patients, nerve root displacement in six and contact of the nerve root with disc material in the remaining eight patients.  

 

What did they find?

The results of this small cohort study indicate distinct differences in QST derived somatosensory profiles and pain experiences between patients with radicular pain only and those with radiculopathy co-morbidity.  Patients with only radicular pain scored significantly lower on the painDETECT score and did not report any symptoms of numbness while 78% of the patients with radiculopathy did.  Patients with only radicular pain were also less anxious, but these two groups had no statistically significant difference in their functional disabilities or in the frequency of Oswestry Disability Index classifications. 

 

Why do these findings matter?

This study supports the notion that radicular pain and radiculopathy are discrete conditions and each condition has distinct differences in QST derived somatosensory profiles and pain experiences.  The authors request that clinicians and researchers should be made aware of these differences and possible care implications.  They should also be aware that the definition of “sciatica” requires much more clarity in its classification and operational guidance.

 

Distinguishing radicular pain from pathological pain, as in the case of neurological compromise with radiculopathy, can be an important distinction and should be shared with the patient. At Dynamic Disc Designs, we have developed models to help professionals explain the difference in a realistic way.

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Correlation Between Proteolytic Enzymes and Micro Angiogenesis in Degenerative Intervertebral Disc Nucleus

Degenerative Intervertebral Disc

Goal of the Study?

In this case-control study from the Journal of Investigative Surgery 1 the authors’ goal was to determine if a correlation exists between proteolytic enzymes and micro angiogenesis in degenerative intervertebral disc nucleus.  

 

Why are they doing this study?

Current pathological studies of intervertebral disc degeneration reveal apoptosis of nucleus pulposus cells in the intervertebral disc.  This leads to matrix reduction, conversion of type II collagen into type I and type III collagen, fibroblast proliferation, nerve fibre ingrowth and micro angiogenesis.  However, there is little information about pleiotropic enzymes associated with degenerative changes in vertebral disc herniation and angiogenesis.  This study was designed to assess how much the severity of the tissue generation was related to the level of pleiotropic enzymes in neovascularization and lumbar disc herniation.

 

 

What was done?

Forty patients with degenerative disc nucleus who had clear clinical symptoms of lumbar degenerative disease and cervical stenosis were selected as the case group.  Twenty patients that had cervical and lumbar vertebra injury caused by trauma and with matching demographics (age, gender, etc.) were selected as the control group. Three-milliliter venous blood was taken from the patients in each group and nucleus pulposus tissue was obtained. The embedded tissue wax block was dried, sliced and hematoxylin and eosin (H&E) dye used.  Various endothelial markers, proteolytic enzymes and content of type i/II/III collagen were measured and statistical correlations were calculated.

 

What did they find?

A statistically significant multiple linear relationships was found between the two independent endothelial markers; Alanine Aminopeptidase (APN) and Leucyl Aminopeptidase(LAP)  with the dependent variable Microvessel Density (MVD).  It was also determined that individually the effects of APN and LAP on MVD were statistically similar.

 

Why do these findings matter?

Protrusion of the disc to the epidural space appears to result in disintegration of inflammatory cells, granular tissue formation, neovascularization and activation of proteolytic enzymes. Correlation studies, such as this one attempt to find various relationships between independent and dependent variables.  This study examined the relationship between various endothelial markers to enhance our knowledge base and ultimately improve our clinical diagnosis ability.

 

At Dynamic Disc Designs, we create models with both an annulus and a nucleus so relevant research can be translated in educational and inter-professional circles. Patient education has been our priority but we are finding educational institutions are purchasing our models for the purpose of student learning.

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Clinical and Radiological Follow-Up Results of Sequestered Lumbar Disc Herniation

disc herniations, sequestered lumbar disc herniation

Goal of the Study?

In this follow-up cohort study published in the Karger Open Access Journal 1 the authors assessed clinical and radiological follow-up results of surgical and non-surgical patients with a sequestered Lumbar Disc Herniation (LDH).  The goal was to determine if a difference existed between patients that had early surgery versus ones that had no surgical intervention.

 

Why are they doing this study?

The authors state that clinical and radiological follow-up studies on sequestered LDH patients who underwent surgery with those who had conservative treatment without surgery are very rare.  Some previous research has shown that early surgical intervention reduced pain faster in the short term, but both treatments had similar benefits in the medium and long term.  In this study, both pain and MRI images were used to analyze the difference between these two treatment modalities.

 

What was done?

LDH patients were identified by detecting a minimum of one plane herniated disc mass (fragmented) separated from the disc.  Of these 98 patients, 32 of them had had surgery within the first month of diagnosis.  These were designated the operated group. The other 66 patients in the non-operated group were treated conservatively with a variety of analgesic or myorelaxant drugs, physical therapy, exercises, lumbosacral orthosis rest, and epidural steroids.   Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) scores were measured at the outset and at the first, third and six-month visits.  Radiological evaluation was performed by measuring the sequestered LDH level and herniation volume using MRI at the outset and at four and six months.  Based on the MRI images at the fourth month, the non-operated group was divided into 3 categories; non-regression (no change in disc volume), partial regression (> 25% herniation reduction) and complete resolution where herniated disc volume is absent.  Statistical techniques were used to compare the various groups.

 

 

What did they find?

In a comparing the group that had surgical intervention versus the group that did not have surgery, it was found that:

  • As a group, the 32 patients in the operated group had significantly lower ODI scores than the 66 patients in the non-operated group after the first and third months.  At the sixth month, both groups had similar clinical pain measurements.
  • Radiological improvements were observed in approximately 90% of non-operated patients who received conservative treatments.
  • At the outset there was no significant difference in the initial VAS and ODI pain measurement scores between the three non-operative subgroups; non-regression, partial regression and complete resolution, but at month one, three and six there were significantly higher pain scores for the non-regression group.

 

Why do these findings matter?

Based on this study, the authors recommend that patients with sequestered LDH receive conservative treatments and not surgical intervention at least for the first six months.  At the end of six months if spontaneous regression is not observed only then should surgery be considered.

 

At Dynamic Disc Designs, we take our education seriously and craft models to help you deliver important clinically relevant, evidence-informed, patient education. In the case of a sequestered lumbar disc herniation, these authors suggest you give it six months of conservative care before considering surgery. Our Professional LxH Model can help show the patient the nucleus and its potential for resorption.

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Compression and Bending (Not only Bending) Caused Disc Herniation in this Animal Model Research

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.

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Extruded disc herniations are experienced earlier by inactive young people in the high-tech gaming era.

disc herniations, sequestered lumbar disc herniation

Goal of the article?

The goal of this study, 1 is to examine why there is an increasing incidence of disc herniation in young people. 

 

Why are they doing this review?

Disc herniation is often the result of natural degeneration changes accompanied by age as the vertebral discs lose water and become less resilient and less responsive to dynamic shock. However, increasingly, disc herniations are appearing in younger people. The cause of this early degeneration is most likely from inactivity sustained by static compressive loads, as well as other factors such as smoking, obesity, familial predisposition and other factors like prolonged sitting. As this can have long-term implications, understanding causes and potential treatments of early degeneration is critical to minimizing the negative outcomes for individuals and society at large.

 

What was done?

This is a prospective study with a total of 33 young patients, all with extruded lumbar disc herniations managed by conservative or surgical approaches between 2017 and 2018. On average, patients were 25 years old. In addition to age, the researchers asked each patient about smoking, familial predisposition, sporting activity, and occupation. They measured pain using a visual analog scale (VAS) and measured patients’ BMI. All patients had lumbar MRI imaging.

 

Helping patients understand compressive loads with a Dynamic Disc Model

 

What did they find?

The researchers found that 18 patients (8 females and 10 males) had a disc extrusion at the L5-S1 level, 12 patients (8 females and 4 males) had a disc extrusion at the L4 and L5 level, and 3 patients had a disc extrusion at both the L4-L5 and L5-S1 levels. Motor deficits were detected in 4 patients who then required surgical treatment. For these patients, three procedures involved the L4-L5; one had right L5 radiculopathy and motor deficit, while the others were on the left side. 

The remaining 29 patients were treated conservatively with physical therapy and pain medication. They were given information on ergonomics and help with stopping smoking. In follow-up, the VAS scores were reduced, and all patients had lost weight. However, only three patients had quit smoking.

When the researchers looked at occupations, they found that all patients sat during the day and lacked movement. They also found that 61% of the patients were smokers and the mean BMI was 32.5 kg/m2.  Additionally, in line with existing research, this study found that familial predisposition with lumbar disc herniation played a role. 

 

Why do these findings matter?

Understanding factors contributing to early disc degeneration can help patients make lifestyle changes that can postpone pain and mobility issues. 

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Lumbar Lordosis and Disc Herniation in Young Participants – Spine Research

lordosis. degenrative joint disease

Flat Back (Lack of Lumbar Lordosis) and Disc Herniation

Lordosis, or the lack of it, has been thought to be a biomechanical precursor to disc herniation in the lumbar spine. To investigate this possible correlation, a group of researchers from Gothenburg University looked at sixteen young active young patients with a median age of 18yrs old who experienced a disc herniation and underwent discectomy surgery. 1

Lordosis is the curve in the lower back—which they measured before and after the surgery.

Lordosis

Researchers used the Roussouly 4-type classification system to measure the degree of lordosis in the lumbar spine.

The researchers found less lordosis in the subjects that had surgery for their disc herniation. In other words, disc herniation was twice as likely to be present in the group with a flatter back. All the disc herniations were found to be in the lowest two levels of the lumbar spine (L4-5 and L5-S1), consistent with other epidemiological studies. 2

Dynamic Disc Designs Models

At Dynamic Disc Designs Corp. we have worked to represent the anatomy accurately. Our Professional LxH  Dynamic Disc Model is created with 12mm of disc height anteriorly and 10mm posteriorly providing a slight lordotic curve. Further, the model has been created with a higher percentage of nucleus pulposus which is often found in younger lumbar spines. To demonstrate that disc herniation occurs more likely with less lordosis all one has to do is dynamically move the single-level model into a less lordosis position and manually create compression. With more lordosis, the nucleus has a more difficult time penetrating through the outer annulus fissure. This can be an important posture teaching point in the prevention of disc herniation.

If you want to take your patient education to a dynamic level, explore what Dynamic Disc Designs models can do for you, your practice and ultimately, your patients.

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Impact of Lumbar Disc Herniation (LDH) Treatment in Children & Adolescents – A Review

A review 1 in the European Spine Journal went over the treatments available for Lumbar Disc Herniation (LDH) in children and adolescents. The review shared which treatment showed the best results.

Why Conduct Such a Review?

Research has shared that LDH or lumbar disc herniation, while affecting adults, also impacted children as well as adolescents (pediatric LDH). It is important to note that pediatric LDH has a number of distinctive features due to the physiological natures of children and adolescents being unique.

Due to adult Lumbar Disc Herniation getting a lot of focus, there’s still a lot that needs to be understood about pediatric LDH. One of the areas involves the treatment available for such LDH and the possible effects of such treatments.

The current review study was conducted to help present an in-depth look at treatments for pediatric LDH and what they entail.

What Was the Methodology?

The searching strategy involved a literature search using electronic databases such as PUBMED and EMBASE. MeSH terminologies (adolescent, child, intervertebral disc displacement, and treatment outcome) and keywords (LDH, adolescent, and child) were used. There were no limitations applied.

The inclusion criteria involved articles featuring relevant information about LDH in adolescents and children. Related references were included, too. The clinical outcome in the articles was assessed, too. 

Take note; case series that didn’t feature a detailed description of the outcome were excluded. Also, case series involving patients over 21-years-of-age were excluded as well. The age-specific exclusion was because previous research demonstrated the human body had almost reached completion of growth during that time.

In the end, 44 series and a total of 8 case reports (with 1,664 cases) were included in the current review. All of the included articles fell in the 1945 to 2008 timeframe.

What Was Observed?

The review shared that LDH is quite a common disorder among adults. The frequency is believed to be much lower in children and adolescents. In all patients hospitalized for LDH, only 0.5-6.8% of the cases were reported as being pediatric patients.

Pediatric LDH is said to be caused by several potential factors. Self-reported or sport-related injury is considered to be the most common cause. This was because 30-60% of adolescents and children experiencing symptomatic LDH were reported to have a history of trauma before pain occurred. However, adult cases usually didn’t report a traumatic experience before the onset of symptoms.

Some recent studies have suggested trauma being an inciting factor that exacerbated pre-existing lesion in discs.

Another factor is considered to be genetics. It has been reported that 13-57% of adolescents with LDH have a first-degree relative with the same condition.

Looking at it from a clinical perspective, pediatric LDH clinically presents itself similarly to adult LDH. Take note; a distinctive feature is that up to 90% of the patients demonstrated a positive straight-leg raising test. 

This can be explained by the fact the nerve root tension is greater in children and adolescents. Also, adolescents and children had a lower chance of presenting neurological symptoms (including weakness and numbness).

What Were the Treatments?

Coming to the treatment part of the review, there’s Conservative treatment, Intradiscal therapy, and Surgical treatment.

Breaking it down, Conservative treatment for pediatric LDH included physical therapy, bed rest, analgesic and anti-inflammatory agents, and limiting physical activity.

As for Intradiscal therapy, chemonucleolysis was the only type being administered for adolescents and children.

Surgical treatment for pediatric LDH was recommended for pediatric LDH on a case-by-case basis. Percutaneous endoscopic discectomy or PED and Microsurgical discectomy or MD were involved.

What Was Concluded?

The review concluded that the diagnosis for adult and pediatric LDH remained similar. As for the treatment, Conservative methods have been reported to be less effective for pediatric LDH when compared to being used for adults. However, Conservative treatment remained the go-to for pediatric LDH cases.

If the said treatment failed, certain patients could be moved to Chemonucleolysis. Excellent short-term outcomes were reported when pediatric LDH was treated surgically (regardless of the modality). Take note; the outcome decreased during the mid-term follow-up, yet it’s considered effective for the long run.

Except for a few exceptions, Spinal fusion isn’t recommended for pediatric LDH.

The review also reported that pediatric LDH could occur in 10-year-olds and younger, with surgical treatments offering positive results.

From this review, one can realize the need to conduct more research involving pediatric LDH for improving treatments and being ready to address any post-treatment related issues.

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