Background:
Clinical practice guidelines consistently endorse exercise therapy for the treatment of
low back pain (LBP). While exercise is more effective than no intervention, the effect
size of exercise, like other treatments for LBP, is relatively small. While there are
many forms of exercise therapies available (e.g. general exercise, pilates), there is no
clear evidence of superiority of one exercise over another. A widely held belief is that
the small effect for exercise is due to the heterogeneity of people presenting with LBP
and if individual patients could be better matched to the optimal types of exercise, then
the effects of treatment would be greater.A recently published study conducted by the
study investigators provided preliminary evidence supporting the hypothesis of better
outcomes when patients are matched to the appropriate exercise. The study demonstrated
that a simple 15-item questionnaire, the Lumbar Spine Instability Questionnaire (LSIQ),
could identify patients who responded best to either of the most common exercise
approaches for LBP. Participants who had low scores on the LSIQ had better outcomes with
graded activity while those with higher scores had better outcomes with motor control
exercise. Theoretically, motor control would work best on those that have poor
coordination and control of the trunk muscles and graded activity would work best on
those with unhelpful beliefs and attitudes towards back pain. Although the results of
this study have the potential to transform exercise treatment for LBP, validation and
confirmation off the results in a fully powered study using an independent sample is
essential before recommending implementation in clinical practice. Validation and impact
analysis are crucial steps in the investigation of effect modification models.
Research aims:
The primary aim of this study is to evaluate whether pre-identified baseline
characteristics, including the LSIQ, can modify the response to two of the most prominent
exercise therapies (graded activity and motor control) for non-specific LBP.
The secondary aims include a cost-effectiveness analysis of a potential stratified care
model.
Exploratory aims include the evaluation of potential new effect modifiers that may
strengthen the initial prediction model. This include measures of central pain mechanisms
to differentiate nociceptive, neuropathic and nociplastic pain.
Methods:
Participants (414) will be recruited by primary care professionals and will be randomized
(1:1) to receive either motor control exercises or graded activity. Participants will
receive 12 sessions of exercise therapy,delivered by a physiotherapist, over an 8-week
period. The primary outcome will be disability at 2 months measured using the Oswestry
Disability Index. Secondary outcomes will be pain, function and quality of life measured
at 2, 6 and 12 months.
Potential effect modifiers will be the LSIQ, self-efficacy, coping strategies,
kinesiophobia and measures of nociceptive pain and central sensitization. The study will
follow specific guidelines for the conduction of effect modification studies.
Expected outcomes:
The results of this study will provide the foundation for the implementation of the study
results in large scale which would significantly improve the effects of exercise for LBP.
Furthermore, it will provide cost-effectiveness information to guide clinical decision
making. Implementation of this approach would be simple as both treatments are already
widely used and the method to identify subgroups of responders to each approach is
straight forward, quick and at no cost.
