Multi-unit sustained vibration loading platform for biological tissues: design, validation and experimentation

Category: Publication

Authors: Geoffrey T Desmoulin, William S Enns-Bray, Carol R Hewitt, Christopher J Hunter

Publication: Journal of biomechanics

The relationships between mechanical inputs and resulting biological tissue structure, composition, and metabolism are critical to detailing the nuances of tissue mechanobiology in both healthy and injured tissues. Developing a model system to test the mechanobiology of tissues ex-vivo is a complex task, as controlling chemical and mechanical boundary layers in-vitro are difficult to replicate. A novel multi-unit vibration loading platform for intervertebral discs was designed and validated with both independent electronic data and experimental loading of 6 bovine intervertebral discs (IVDs) and an equal number of unloaded controls. Sustained vibration was applied using closed-loop positional control of pushrods within four independent bioreactors with circulating phosphate buffered saline. The bioreactors were designed to be modular with removable components allowing for easy cleaning and replacement. The loading regime was chosen to maximize target mRNA expression as reported in previous research. Aggrecan, decorin, and versican mRNA all reported statistically significant increases above control levels. Biglycan, collagen type I and II showed no significant difference from the control group. Further study is required to determine the resulting effect of increased mRNA expressions on long-term disc health. However these results indicate that this research is past the proof of concept stage, supporting future studies of mechanobiology utilizing this new device. The next stage in developing this novel loading platform should consider modifying the tissue grips to explore the effects of different directional loading on different gene expression, and also loading different types of tissues

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Noninvasive Intervention Corrects Biomechanics and Upregulates Disk Genes for Long-Term Spinal Health

Category: Publication

Authors: GT Desmoulin, C J. Hunter, C R. Hewitt, N Bogduk, O S. Al-Ameri

Publication: Global Spine Journal, Volume 2, Issue 1_suppl, Pages s-0032-1319852-s-0032-1319852

Studies examining associations between back pain and degenerated intervertebral disks (IVDs) produced evidence implicating IVDs as a significant factor in chronic back pain. Traditionally, treatment is focused on symptoms instead of at the root of discogenic back pain, the disk itself. Further, invasive treatments range from use of strong medications to surgery, which can have poor outcomes and problematic side effects. There is now a noninvasive intervention capable of correcting spinal biomechanics and has been “tuned” to upregulate the expression of IVD genes responsible for producing matrix proteins in hopes of therapeutically addressing discogenic back pain at its root. The intervention is called KKT and is based on the application of specific vibration to the spine for ∼10 minutes per treatment, 2 to 3 per week, for about 6 weeks before re-evaluation. This abstract summarizes KKT safety and efficacy tests performed thus far.

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Blast Mitigation Status of Police Crowd Management Ensembles

Category: Publication

Author: Desmoulin, G. T., Dionne, J.P.

Publication: White Paper, 2012.

Between 1992 and 2002, more U.S. citizens were wounded or killed from explosives within U.S. borders than all of the international terrorist incidents that occurred during this same time. Yet, according to some researchers, the U.S. healthcare system still considers terrorism an international affair and therefore lacks the knowledge of the public health impact after bombings. Kapur in 2005 and more recently Lerner (2007) published articles outlining the need for non-military terrorism preparedness and the resulting disaster response of civilian factions. These research groups state that criminal bombings utilizing homemade materials occur daily, nearly 5 times a day on average in the U.S.. Although the events of September 11, 2001 have significantly raised awareness of the management of blast injuries in the civilian healthcare community, these research groups still stress that additional explosion specific mass-casualty incidents should be prepared for by civilian disaster management teams, emergency medical services (EMS) personnel, emergency physicians, trauma surgeons, and critical care/burn specialists.

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Spinal Intervention Efficacy on Correcting Cervical Vertebral Axes of Rotation and the Resulting Improvements in Pain, Disability and Psychsocial Measures

Category: Publication

Author: Desmoulin G. T., Szostek J. S., Khan A. H., Al-Ameri O. S., Hunter C. J., Bogduk N.

Publication: Journal of Musculoskeletal Pain, 2012, 20(1): 31-40.

Mean axes of rotation [MAR] of cervical joints are an effective measure of spine pathology. Khan Kinetic Treatment [KKT] is known to relieve symptoms, but its biomechanical effects have not been quantified. This study assesses KKT efficacy using MAR correction and its associated effects.

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Effectiveness of Slow Rate Practice Techniques

Category: Publication

Author: Desmoulin G. T., and Larkin T.

Publication: White Paper, 2012.

The purpose of this paper is for GTD Engineering’s Geoff Desmoulin (GTD) to give scientific insight into slow movement training techniques developed and tested by Target Focus Training’s (TFT) Tim Larkin. In doing so GTD helps validate, continually improves, and, further develops the scientific basis of TFT training methodology. It is understood that while this work has scientific merit it was not the purpose to have this work accepted by a scientific peer-review publication nor has it been submitted anywhere on that behalf.

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A portable inertial sensing-based spinal motion measurement system for low back pain assessment

Category: Publication

Authors: Jung Keun Lee, Geoffrey T Desmoulin, Aslam H Khan, Edward J Park

Publication: IEEE, Pages 4737-4740

Spinal motion measurement during dynamic conditions may help identify differences between individuals with and without low back pain (LBP). The purpose of this paper is to demonstrate the feasibility of an inertial sensing based, portable spinal motion measurement system for investigating the differences of the spinal motions between an LBP group and a healthy control group. During a fast flexion/extension test, we measured 3D angular motions of the pelvis, lumbar spine and thoracic spine of the two groups using the inertial sensing based system. Range of motions (ROM) and peak angular velocities were investigated to determine which variables have significant differences between the two groups (p < 0.05). Also, a logistic regression analysis was carried out to see the classifying ability of the LBP patients from controls using the proposed system. The result shows that LBP was particularly associated with significant decreases in peak velocities of the lumbar spinal extension motion, having the maximum 90% sensitivity and 80% specificity in the classification according to the regression analysis. The result demonstrates the possibility of the proposed inertial sensing-based system to be served as an efficient tool in providing an accurate and continuous measurement of the spinal kinematics.

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Disc strain and resulting positive mRNA expression from application of a noninvasive treatment

Category: Publication

Authors: Geoffrey T Desmoulin, Carol R Hewitt, Christopher J Hunter

Publication: Spine, Volume 36, Issue 14, Pages E921-E928

Study Design. Bovine caudal intervertebral discs were exposed to a noninvasive vibrating intervention for 10 minutes at amplitudes of 0 or 0.5 to 5 g and frequencies of 0, 16, 50 to 80, and a combined 16 + 50 to 80 Hz treatment. Expression of mRNA for aggrecan, collagen type I, collagen type II, biglycan, decorin, and versican were assayed.

Objective. To determine if the intervention is effective in altering intervertebral disc gene expression.

Summary of Background Data. Studies have variously suggested either an increased risk of disc degeneration with vibrations, no effect, analgesic effect, or even positive effects within certain loading parameters. The KKT intervention is in clinical use for spinal ailment pain reduction.

Methods. The intervention was applied in a clinic emulation setup. Gene expression in the nucleus pulposus was assessed using real-time RT-PCR and SYBR Green chemistry.

Results. Expression of mRNAs for aggrecan, collagen type II, and versican were signifi cantly effected by the intervention. Collagen type I, biglycan, and decorin were uneffected.

Conclusion. Expression of the extracellular matrix genes were signifi cantly up-regulated when vibrated with the intervention under specifi c loading patterns, indicating a potential therapeutic stimulus. Further studies on the protein-level and long-term effects are warranted. Previous studies have indicated a mixed effect of vibrations in the human spine. In this study, a clinical intervention using vibrations was applied to bovine intervertebral discs, and gene expression in the nucleus pulposus was measured. Several extracellular matrix genes were up-regulated, suggesting a potential therapeutic effect.

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Comparison of 3D Spinal Motions during Stair-climbing between Individuals With and Without Low Back Pain

Category: Publication

Author: Lee J., Desmoulin G. T., Khan A., Park E.

Publication: Gait & Posture. 2011(34): 222–226.

In spite of the importance of stair-climbing (SC) as an activity of daily living, 3D spinal motion during SC has not been investigated in association with low back pain (LBP). The purpose of this research is to investigate the differences of the spinal motions during SC between an LBP group and a healthy control group, in order to provide insight into the LBP effect on the spinal motions. During two types of SC tests (single and double step SCs), we measured 3D angular motions (flexion/extension, lateral bending, and twist) of the pelvis, lumbar spine and thoracic spine using an inertial sensing-based, portable spinal motion measurement system. For the nine motion variables (i.e. three anatomical planes  three segments), range of motions (ROM) and movement patterns were compared to determine the differences between the two groups. It was found that the only variable having the p-value of a t-test lower than 0.05 was the flexion/extension of the lumbar spine in both SCs (i.e. the LBP group’s ROM < the control group’s ROM). Although the strength of this finding is limited due to the small number of subjects (i.e. 10 subjects for each group) and the small ROM differences between the groups, the comparison result of the t-test along with the motion pattern shows that the effect of LBP during SC may be localized to the lumbar spinal flexion/extension, making it an important measure to be considered in the rehabilitation and treatment of LBP patients.

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Free Axial Vibrations At 0 to 200 Hz Positively Affect Extracellular Matrix Messenger Ribonucleic Acid Expression in Bovine Nucleus Pulposi

Category: Publication

Authors: Geoffrey T Desmoulin, Carol R Reno, Christopher J Hunter

Publication: Spine, Volume 35, Issue 15, Pages 1437-1444

Study Design. Bovine caudal intervertebral discs (IVDs) were exposed to free axial vibration for 10 to 60 minutes at 0 to 0.5g and 0 to 200 Hz. Expression of messenger ribonucleic acid for aggrecan, collagen type I, collagen type II, biglycan, decorin, and versican were assayed, as was apoptosis.

Objective. To determine the vibration conditions which are most effective in altering intervertebral disc IVD gene expression.

Summary of Background Data. Various studies have suggested widely varying effects of vibration in the IVD, ranging from harmful (increased risk of degeneration) to beneficial (increased analgesia) to neutral (no effect).

Methods. Vibration was applied using a custom designed voice coil system, which generated controlled motion in the axial direction. Gene expression in the nucleus pulposus was assessed using RT-PCR and the SYBR green chemistry; apoptosis was assessed using TUNEL staining.

Results. Expression of messenger ribonucleic acids for biglycan, collagen type I, collagen type II, decorin, and versican were significantly affected by vibration duration, frequency, and amplitude. Aggrecan was unaffected. Of the 3 factors, amplitude had the largest and widest effect.

Conclusion. Expression of extracellular matrix genes was significantly upregulated at high amplitudes (0.4 g) in as little as 10 minutes. This may indicate a potential therapeutic stimulus; periodic application of controlled vibration could positively influence matrix maintenance. Further studies on the protein level and long-term effects are warranted.

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Is Vibration Truly an Injurious Stimulus in the Human Spine?

Category: Publication

Authors: Taryn E Hill, Geoffrey T Desmoulin, Christopher J Hunter

Publication: Journal of Biomechanics, Volume 42, Issue 16, Pages 2631-2635

Epidemiological data at one time was taken to suggest that chronic vibrations—for example operating vehicles with low-quality seats—contributed to intervertebral disc degeneration and lower back pain. More recent discussions, based in part upon extended twin studies, have cast doubt upon this interpretation, and question how much of the vibration is actually transmitted to the spine during loading. This review summarizes our recent survey of the current state of knowledge. In particular, we note that current studies are lacking a detailed factorial exploration of frequency, amplitude, and duration; this may be the primary cause for inconclusive and/or contradictory studies. It is our conclusion that vibrations are still an important consideration in discogenic back pain, and further controlled studies are warranted to definitively examine the underlying hypothesis: that chronic vibration can influence IVD cell biology and tissue mechanics.

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