PFC Researcher profile: Eric Parent, P.T., M.Sc., Ph.D.
Eric Parent was awarded the 2015 OrthoCanada Award for Research in Neck and Back Rehabilitation and Core Stability:
1. What is the topic of your research:
Evaluation of the effects of Compression and Traction on Intervertebral Disc Water Content and Morphology in Patients with and without Low Back Pain.
2. Your research hypothesis:
- The response to extremes of loading of the new MRI measurements investigated will differ between participants presenting pain or not showing pain.
- The response to extremes of loading (compression vs traction) of the new MRI measurements investigated (centroids of the distribution of fluid within the disc) will differ between participants presenting mild and severe disc degeneration.
If this is the case, our approach will show promise to improve the pathoanatomical classification of back pain when planning for different mechanical treatments.
Getting funded by PFC provides confirmation that my work is relevant in the PT community
3. What did you discover?
Loading vs pain
Fifteen patients with chronic LBP matched to 15 controls for age, weight and gender, were imaged after spending 20 minutes in each position beginning in a supine relaxed position, then with 50% body weight compression load, and finally with 50% body weight traction load.
The response of lumbar motion segments to loading conditions detected more differences between participants with and without LBP than comparisons only of measurement from unloaded images. Biomarkers reflecting an anterior-posterior shift in fluid distribution within discs and nucleus and disc height and their response to loading showed promise to improve the specificity of MRI for LBP.
Significant interaction effects between pain and loading for:
a:) horizontal coordinate of the disc centroid of the fluid distribution when going from unloaded to compression
b:) horizontal coordinate of the disc centroid of the fluid distribution when going from compression to traction
c:) vertical coordinate of the disc centroid of the fluid distribution when going from unloaded to compression
D:) vertical coordinate of the disc centroid of the fluid distribution when going from compression to traction
E:) vertical coordinate of the nucleus centroid of the fluid distribution when going from unloaded to compression
F:) vertical coordinate of the disc centroid of the fluid distribution when going from compression to traction
(images only illustrate direction and location of the effects and are not scaled)
Loading vs degeneration
35 participants with and without pain were imaged using the same protocol as above. Less lumbar disc degeneration correlated with larger measurements differences between loading conditions. The largest loading responses were observed at lower levels with less degeneration. The centroid of the fluid distribution within the disc and nucleus, the centroid of the disc shape, the motion segment angle and disc height detected the largest response to lumbar compression and traction loading.
From compression to traction, we observed significant:
- increase in L3-4 nucleus water content;
- inferior and posterior shift in L4-5 (effect sizes =0.4, 0.14) and L5-S1 (0.25, 0.33) centroid of the fluid distribution within the disc;
- inferior and posterior shift in the L5-S1, as well as a posterior shift in the L4-5 nucleus centroid of the fluid distribution.
Significant differences from compression to traction for a:) disc centroid of the fluid distribution b:) nucleus centroid of the fluid distribution (yellow) and centroid of the shape of the region (brown) and c:) disc height d:) disc and nucleus fluid content (images illustrate the location and direction of the effects but are not scaled according to magnitude)
4. How has your research helped your field of study?
Two chapters of a thesis were written and two manuscripts are being finalized for publication based on work funded by this grant. This research project led to finalizing the development of a semi-automated image analysis software in which we implemented the new measurements of the location of the centroid of the fluid distribution within regions of interest.
It also confirmed our hypothesis that there is a better relationship between MRI findings in response to loading than when only imaging the spine at rest, justifying our interest in studying changes in response to mechanical loading in cases with chronic pain.
We have also introduced traction as a contrast to compression which has been very little studied in the past. We demonstrated that changes between compression and traction were more measurable than those between compression and the relaxed supine position.
5. What should physiotherapists know about your findings?
Our research confirms the belief of many physiotherapists that the mechanical response of the spine to loading is more closely related to pain and degenerations processes than relaxed supine imaging. Our findings also demonstrate that fluid distribution parameters may help understand chronic low back pain better in the future.
6. How can this research help Canadians?
It justifies continued investigation in the novel measurements of fluid distribution and in the loading protocol within the conventional MRI. If findings are confirmed in a larger study, in the future we may improve the treatment of chronic low back pain.
Our findings may lead to offer more personalized focused treatments for a group where currently the diagnosis is often unclear (labelled non-specific low back pain).
7. What’s your motivation for pursuing this research? Why have you decided to go above and beyond?
From my first year of physiotherapy training I developed an interest in research methods and addressing questions yet unanswered about orthopaedic care. I was inspired by Helene Moffet, my research methods professor, and joined her lab as a summer student. I then continued with a research assistantship in my last year.
After practicing privately for a few years, I determined there were many unanswered questions about the best strategies to treat many MSK conditions. I signed up for a MSc mostly to learn research methodology, and went on to find training opportunities where I could explore questions related to low back pain.
I worked with Michele Crites Battie for my PhD developing MR imaging expertise, which we built on in this latest project. This is part of my research program where I hope to refine the imaging methods to inform care decisions for low back pain.
8. What does PFC mean to you?
PFC has been an important source of funding as I was developing new ideas. It is a sounding board funding research for PTs with appraisal done by PTs.
Getting funded by the PFC provides confirmation that my work is relevant to the PT community.
Thank you again for the support.
9. More information about Eric’s research
Some of my research is listed here:
A Ph.D thesis was submitted by Vahid Abdollah to University of Alberta January 12 2017 entitled The Effects of Axial Loading on the Disc and Motion Segment Relative to Disc Degeneration and Pain Using Novel MRI Biomarkers. Abstract will be submitted in the coming year for results summarized in Vahid Abdollah’s thesis chapter 7 and 8. The Ph.D thesis above contains 2 chapters directly resulting from the grant to be submitted for publication in the coming weeks.
CHAPTER 7 CHAPTER 7 EVALUATION OF THE EFFECTS OF LOADING AND DISC DEGENERATION ON LUMBAR INTERVERTEBRAL DISCS AND MOTION SEGMENTS
Vahid Abdollah; Eric C Parent; Alex Su, Keith Wachowicz, Michele C Battié
CHAPTER 8 THE EFFECTS OF COMPRESSION AND TRACTION ON LUMBAR MRI FINDINGS IN RELATION TO CHRONIC LOW BACK PAIN
Vahid Abdollah; Eric C Parent; Alex Su, Keith Wachowicz, Michele C Battié
A public Ph.D presentation has been held December 21 2016.