Analysis of Time-Dependent Adaptations of Lumbar Intervertebral Disc Morphology during Standing-Induced Symptoms of Low Back Pain
Date of Award
Master of Science (MS)
Low back pain (LBP) is a traumatic impairment for individuals with staggering socioeconomic burden. The etiology of LBP is exceedingly complex and confounded by comorbidities. The source of pain is difficult to pin-point because the offending stimuli are not always known. One promising avenue is to investigate the progression of LBP symptoms in young and otherwise healthy individuals. The population that exhibits preclinical LBP in prolonged standing may be particularly suitable for understanding the anatomical changes that occur during the progression of the symptoms. Since the pain symptoms subside upon exiting the standing position, they are an ideal demographic to investigate the initiating pathoanatomical mechanisms of LBP. As the intervertebral discs are thought to give rise to a great proportion of LBP cases, the objective of this thesis is to explore the relationships between standing LBP and the three-dimensional morphology of the lumbar intervertebral discs over time. These relationships were explored in three different stages by comparing those with and without standing LBP in supine, at the time of assuming the standing position, and longitudinally in the standing position for 105 minutes. A 40-participant cohort was recruited and imaged with T2 positional MRI in each stage. Linear mixed models with a time-dependent autoregressive covariance structure were used to evaluate the differences in intervertebral disc morphology between pain developers (PDs) and non-pain developers (NPDs). While the imaging in supine and the initial standing positions alone were not sufficient to detect differences between PDs and NPDs in males or females, inclusion of images over a prolonged standing regimen revealed differences in disc height and the relative signal intensities of the nuclei pulposi in female PDs. There was also a significant correlation between the magnitude of pain and characteristics at certain lumbar levels in both female and male PDs. Future work will focus on identifying specific imaging biomarkers implicated in the initiation of chronic LBP. This study seeks to advance the understanding of the role of the lumbar intervertebral discs in standing LBP to inform future clinical decisions.
Simon Y. Tang, PhD
Linda Van Dillen, PhD Ismael Seáñez, PhD