fissures in the annulus fibrosis, model

A recent study found that fissures in the annulus fibrosis can create a biomechanical and chemical environment that is conducive to the ingrowth and formation of blood vessels and nerves, which may contribute to back pain in patients with disc degeneration—particularly of the lumbar segments. An examination and analysis of cadaveric discs used safranin staining to examine the proteoglycan loss and measure the water concentration in the 25 surgically-removed discs and compared the data from intact and disrupted annular region to quantify the extent to which a reduction in compressive stress might allow blood vessels to grow and thrive within annular fissures. Results indicated 54 percent less proteoglycan content in the fissured annulus than in the intact samples, with only a slight reduction in water content.


Examining the Link between Fissures and Nerve Growth

Persistent lower back pain—particularly of the lumbar intervertebral discs—often presents with severe symptoms that can lead to long-term disability and loss of earnings. Chronic pain may be the result of posterior annulus fibrosis and the stimulation of the sinuvertebral nerve. Previous studies have demonstrated that the injection of neurotoxins into the compromised discs can curtail this nerve pain for up to two years. While studies have shown that disc degeneration increases the risk of lower back pain, much of the focus of previous research has been on the association between structural defects, such as endplate defects and a loss of annular height, rather than biochemical changes.

Radial fissures in the annulus, with, or without disc herniation, are considered a strong indicator of LBP. The subsequent in-growth of blood vessels and nerves into these fissures can sensitize the disc area and cause inflammation, which may cause pain in some—but not all—with disc degeneration. Researchers involved in this study supposed a possible causal link between annulus fissures and nerve ingrowth.

lumbar models

A professional lumbar spine model with a demonstration of in-growth of nerves and blood vessels from fissures in the annulus fibrosis.

Three Comparative Studies of Thoracolumbar Spine Segments

Three consecutive studies of surgically-removed cadaveric thoracolumbar spine segments from subjects who had experienced no spinal injury or extensive bed rest prior to death were compared with 25 samples taken from 18 cadavers of patients who had suffered from LBP, disc herniation, scoliosis, or spondylolisthesis prior to being deceased. The first study used die to identify annular fissures in 35 discs and radiographs to assess disc degeneration and height. Stress profiles were then performed on the segments in flexion and extension postures and then repeated following two hours of “creep” loading to simulate the rate of disc dehydration that might occur after a day’s activity. The discs were then dissected and photographed, then graded to determine the scale of degeneration.

The second study measured focal loss of proteoglycans from annular fissures in 25 samples using a custom-made software program, and a third study measured the loss of sulphated glycosamineoglycans in the fissured annulus.


Results—Higher Levels of Stress Reduction and Proteoglycan Loss in DD Samples

The analysis of the three studies indicated a compressive stress reduction of between 36 and 46 percent within the annulus fissures. The level was higher in degenerated discs. The fissured annulus regions had between 36 and 54 percent less proteoglycans than intact areas of the same discs, though the water content was only slightly reduced.

Pressure Reduction Contributes to Loss of Proteoglycans and Nerve Growth

The reduction of pressure inside the annulus fissures creates a biochemical environment that is conducive to the loss of focal proteoglycans. This allows for the in-growth of blood vessels and nerves within the fissured areas. These findings suggest that the injections of therapeutic neurotoxic dyes into the affected fissures could disable the in-grown nerves and help alleviate LBP in some patients.

KEYWORDS: Link Between Annular Fissures and In-growth of Blood Vessels and Nerves; fissures in the annulus fibrosis can create a biomechanical and chemical environment that is conducive to the ingrowth and formation of blood vessels and nerves; reduction in compressive stress might allow blood vessels to grow and thrive within annular fissures; possible causal link between annulus fissures and nerve ingrowth; reduction of pressure inside the annulus fissures creates a biochemical environment that is conducive to the loss of focal proteoglycans; posterior annulus fibrosis; persistent lower back pain

spinal canal, spinal spacing

In a research paper published in Miltary Medicine, spinal canal spacing was found to be a better predictor in the development of chronic low back pain when compared to intervertebral disc degeneration. 1

These researchers used MRI to look at the role of spinal stenosis, disc degeneration, nerve root compression in low back pain among Finnish males ages 18-26. They looked at the intervertebral foramen (exiting nerve canals) and the midsagittal slice examining spacing of 108 of these subjects that had chronic low back pain comparing 90 asymptotic controls without chronic low back pain.

With the prevalence of degenerative disc disease in a reported 52% of Finnish 15-29yrs of age, the authors thought it would be good to determine if degeneration was related to chronic low back pain.

What they found was those who had reduced spinal canal spacing at the L1-L4 were more likely to exhibit chronic low back pain.

Disc degeneration is identified by disc height loss. And with disc height loss, there are spacing changes that take place in the intervertebral foramina and the spinal canal. Congenital spinal canal variations 2 can predispose a person to acquire low back pain but the maintenance of disc height, even in those people, should be priority number one. Disc height is diurnal and will vary with mechanical forces that people have complete control over.

At Dynamic Disc Designs, we have designed models to help convey these important low back pain topics, to help the patient understand clearly how spinal canal spacing, intervertebral disc narrowing, disc protrusion and intervertebral foraminal narrowing can impact function. Our dynamic disc models help the patient get to know their own back pain and how the postures, loads and motions can have a profound impact on their management of the pain.

Professional LxH Disc Model, spine models, lumbar model, professional LxH, disc herniation, model, spine models

A dynamic disc model showing flexible movements of the intervertebral disc with an annulus and nucleus.


lumbar spinal stenosis, spinal canal narrowing

A superior view of our Lumbar spinal stenosis model with a dynamic disc bulge and dynamic ligamentum flavum.

MDT, mechanical diagnosis, spine, low back pain

A study of 45 musculoskeletal disorder patients in Japan sought to determine the extent to which mechanical diagnosis and therapy (MDT) could help patients in the self-management and self-monitoring of their pain symptoms. The results of the study indicate that MDT is effective in helping patients to understand, monitor, and manage their own pain and symptoms of musculoskeletal disorders.


The Study Subjects Received MDT Twice a Week for One Month

The subjects involved in the study included 45 outpatients from an orthopedic clinic in Japan. Each subject suffered from a musculoskeletal disorder that had been previously diagnosed by an orthopedic surgeon. Only patients without medical contraindications to MDT techniques could participate. Those with fractures, infections, or severe osteoporosis were excluded from the study, as were patients with diagnosed cognitive or neurological disorders or who were undergoing other forms of medical intervention. Each participant was involved in outpatient physiotherapy at a local orthopedic clinic and was over the age of 20 years-old.

Establishing a Baseline and Follow-Up to Track Progress

Each subject in the study received MDT from a qualified MDT physical therapist for 20 to 40 minutes, up to twice a week. The intervention included physical evaluations, a discussion of the patient’s medical history, and MDT-classified managements. Follow-up visits addressed any problems with the therapy, and appropriate adjustments of the techniques were made. The MDT visits were conducted for approximately one month, and a baseline questionnaire was completed by the subjects at the beginning of treatment and in a follow-up consultation, one month after the end of their treatment period. The Health Education Impact Questionnaire and the Self-monitoring and Insight and Skill and Technique Acquisition scores rated the subjects’ answers to compare the proportion of subjects who demonstrated a positive “reliable change” in self-monitoring, insight about their conditions, and the ability to self-manage their symptoms after having undergone MDT.


Improvement in Self-Monitoring and Self-Management Skills Post-MDT

The results of the study indicated a significant improvement in the subjects’ abilities to self-monitor, have insight into, and manage their own musculoskeletal disorders after a series of MDT treatments over the course of one month. In addition to gaining valuable insight into and ways to manage their own conditions, more than 71 percent of the study’s participants experienced meaningful improvement in their physical condition after an average of 3.8 MDT sessions. The results of the study compare favorably to previous studies of passive therapeutic forms, where patients receive therapeutic manipulations by their practitioners, without being educated or counseled about the condition being treated. The results of this study indicate that MDT is not only an effective means of treatment for patients with musculoskeletal disorders, but it empowers patients in learning to self-manage and monitor their own symptoms and dysfunction.


KEYWORDS: Mechanical Diagnosis and Therapy Helps Patients Self-Manage, mechanical diagnosis and therapy (MDT) could help patients in the self-management and self-monitoring of their pain symptoms, significant improvement in the subjects’ abilities to self-monitor, have insight into, and manage their own musculoskeletal disorders after a series of MDT treatments, effective means of treatment for patients with musculoskeletal disorders, pain and symptoms of musculoskeletal disorders




dynamic disk

The dynamic disk plays a significant role in the resistance to compression. It is known to physically compress over the course of the day by as much as 20 percent with recovery achieved during sleep or recumbency. Its implications intertwined with back pain. 1 One of the focused investigations into its essential function has been its intrinsic ability to maintain and absorb water. Negatively charged proteoglycans contain properties that attract water, and it is this hydraulic characteristic believed to be at the core.

However much still is to be discovered; especially in the higher understanding how best to draw in fluid and recover the expulsion of this water under axial compression. In a manuscript published in the Journal of Biomechanics 2, researchers worked to answer the questions regarding loading and unloading of the dynamic disk.

The researchers revealed a new personality of the annulus fibrosis as playing a significant in the ability to absorb water. The annulus demonstrated both properties of viscoelasticity as well as the binding capacity to retain water. This information is new in the better understanding of how disks maintain vertebral spacing with regards to recovery. Load and unloading cycles are natural, but it is the intrinsic ability of the dynamic disk to maintain spacing over time that is important to continue to study. Congratulations to the authors for choosing a worthy investigation.

At Dynamic Disk Designs, we work to model the dynamic nature of the spinal structures to improve communication of spine science. Our work facilitates patient education and student teaching of spine. Having a model dynamic disk allows the better understanding of disk height loss over time to explain back pain mechanics and the respective hydraulic solutions.


Posture and Loading

In a signature paper by Broom et al. 1 these authors set out to investigate the effects of complex posture within the act of loading.

They used thirty seven motion segments of ovine lumbar spines and subjected them to compressive loading to simulate the event that a human may experience when they bend and twist while lifting a heavy object. What they found was the more complex (meaning more rotation) the angles were, the more likely they saw ruptures within the intervertebral disc.

These injuries were looked at with microstructural analysis with light microscopy and they saw pockets of nucleus pulposus between the annulus fibrous with evidence of delamination. They saw convoluted paths of injury which displaced the nucleus more so in the complex loading environment. They also saw how the nucleus tracked laterally and then in a circumferential pattern.


The authors concluded that postures do matter when it comes to loading the disc. And their bottom line is to keep the spine square if you want to avoid an injury that relates to a disc herniation.

ligamentum flavum, posterior stability, facets

An MRI study of 162 patients with lower back pain (LBP) and/or leg pain (LP) measured and analyzed the thickness of the ligamentum flavum (LF) at different levels of the lumbar spine and concluded that, though the LF thickness increased with the age of the patient, there was no apparent correlation between a decrease in disc-height and LF thickness. In fact, researchers found that LF thickness had already begun to increase in patients under 40, refuting the theory that LF thickness was caused by buckling of the LF into the spinal canal due to age-related degeneration.


The Study

The researchers involved in this study wanted to examine the theory that hypertrophy of the LF—which covers the postural-lateral spinal canal—is caused by age-related degeneration. Subjects included 87 female and 75 male LBP patients whose mean age was roughly 52-years-old. Patients with scoliosis, spinal fracture, or other deformities of the spine were excluded from the study. Radiographs were conducted, and the thickness of 648 LF was measured at various levels of the lumbar spine, and an analysis was performed by the researchers using Pearson’s coefficient test.


Three important findings were achieved during analysis of the MRI results in this study: LF thickness increases with age; this thickness is not as pronounced at the L2-3 and L5-S levels as in other levels; the LF thickness was extremely pronounced at the L4-5 levels, particularly in younger subjects. Researchers concluded that LF thickening was already in progress in the back-pain study patients between the ages of 30-39.


The results of this study indicate that practitioners should pay close attention to posterior, as well as anterior, elements of disc herniation patients prior to planning for surgical procedures. Thickening of the LF in LBP patients is more likely to occur prior to the age of 40 and is not caused by disc degeneration and LF buckling into the spinal canal, as has been previously suggested. Patients with obvious thickness of the LF at L2-3 should be examined for lumbar spinal canal stenosis, as the results of the study indicate a correlation between the two conditions.

Blurb: A study of lower back pain patients measured and analyzed ligamentum flavum (LF) at different levels of the lumbar spine and concluded that LF thickening occurs in younger (30-40) LBP patients and is not caused by buckling of the LF into the spinal canal due to age-related degeneration.

prone push-up, MRI

In an article in Musculoskeletal Science and Practice, researchers looked to quantify the hydration changes with the McKenzie prone push-up and MRI.

The intervertebral disc supports most of the weight in the upright posture. It is the largest avascular tissue in the human body and is a common source of pain in the case of discogenic problems. A popular therapeutic technique to reduce disc herniation is the McKenzie prone push-up. This is thought to centralize the nucleus pulposus of the disc to allow an improvement in healing.

prone push-up

Popular movement strategy for disc problems (source:

MRI Methods

Using MRI, the authors attempted to measure the pixel density of T2 weighted images to estimate disc fluid content and displacement. As a base line, they had the 22 subjects lay down for 40 minutes before the study began. Then, they had the subjects conduct a series of prone push-ups to immediately follow-up with MRI imaging. They looked at the midsagittal slice of L4-5 and L5-S1.


In their conclusion they did not see any significant pixel re-orientation suggesting that the disc did not change with respect to hydration content. They did see significant anterior displacement at the L4-5 level, however.

Limitations to the Study

It is important to note that in the methods there were many limiting factors. For one, the researchers instructed the subjects to lay down for 40 minutes prior to the study. Previous work has shown that laying down for 10 minutes has an effect on disc height and respective hydraulics of the lumbar discs. Therefore, the subjects may have already had changes prior to the beginning of the prone push-ups. Another significant limitation to the study was that only the midsagittal section of the disc was measured and therefore changes outside of the field of view was not measured.

A congratulations to the authors for publishing this manuscript. However, much more research must be conducted to suggest that the prone push-up does not affect hydration and/or distribution of the intervertebral disc.