Electronic Thesis and Dissertation Repository

Thesis Format



Doctor of Philosophy


Physical Therapy

Collaborative Specialization

Musculoskeletal Health Research


Walton, David

2nd Supervisor

Birmingham, Trevor


3rd Supervisor

Atkinson, Hayden

Joint Supervisor


The signs and symptoms of low back pain (LBP) associated with disc herniation (DLBP) and its underlying mechanism(s) are not well supported. One theory proposes that some low back pain (LBP) is the result of a disc herniation compressing adjacent tissues innervated with nociceptors. The theory proposes that spinal manipulation (SM) and/or mobilizations (SMOB) can reduce the size and position of the herniation, and relieve pain and improve range of motion. There is no research to support or negate the theory even though clinical evidence supports its plausibility.

In this three-part study we examined clinical practices that have an anecdotal history of success. Part one consisted of surveying international clinicians in order to determine their perspectives on the signs and symptoms of DLBP. We then compared those views against published literature through a systematic review. The third part of the study used magnetic resonance imaging (MRI) technology to examine for evidence of change in order to test the hypothesis that disc morphology (i.e., the size and position) can be altered through a specific spinal movement or position. Our findings showed that clinicians who screen for DLBP appear to follow what little guidance is available however most rely instead on theory, experience, and intuition. Despite the large numbers of proposed features of DLBP, this study shows that there is a need to develop valid and reliable criteria for it’s diagnosis. With the exception of the centralization phenomenon, there remains no consensus on reference-based index tests that would help clinicians to identify DLBP. There remains a gap between clinical practice and evidence on the use of spinal manipulative therapy (SMT) for LBP. Currently there is no clear evidence to assist clinicians to determine the subgroup of LBP patients that respond best to SMT. This study demonstrated a reliable method for measuring changes in disc shape. Future studies should focus on understanding these responses in larger and more diverse samples, as well as their clinical relevance in patients with existing discogenic low back pain.

Summary for Lay Audience

Low back pain is something most people experience. It may be caused by a single incident, such as lifting a heavy object. For others it may be connected to postures such as sitting in uncomfortable positions for long periods of time, or doing repetitive movements at work or at home. People who have low back pain may visit a physiotherapist, a chiropractor or another medical clinician to try to get a diagnosis and treatment for the pain. The clinician will ask questions about symptoms, how they started, what makes them worse or what provides relief. They will then do a physical examination involving different tests and procedures. Currently, there are few guidelines to help clinicians determine the exact cause of low back pain. Our study surveyed clinicians to find out how they determine what is the problem with people suffering low back pain and how they go about treating the symptoms. We then compared what clinicians told us with what the latest research has to say about low back pain. We found some areas of agreement between the literature and what clinicians told us. We suggest that clinicians and researchers work together to develop better guidelines for examining and treating patients with low back pain.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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