Introduction: Some people with Lumbar Disc Degeneration (LDD) experience recurrent low back pain (LBP) and others do not and it is unclear why. This thesis investigates the biomechanical differences between those with LDD and LBP and those without through the examination of intrinsic lumbar spine shape, postural adjustments and kinematic strategies.
Methods: Patients and healthy controls were recruited and consented to our cross-sectional cohort (ethical approval reference13/LO/0793). T2 weighted images (L1-S1, 3T MRI) were acquired and groups identified based upon LDD grade (Modified Pfirrmann grading) and the presence of LBP. Intrinsic lumbar spine shape was investigated using Statistical Shape Modelling (SSM). Postural and kinematic strategies were examined during gait, sit-to-stand and bespoke perturbation tasks using surface electromyography (eight bilateral trunk and lower limb muscles) and a novel marker set, the ‘Imperial Spine’ (three segmented spine and bilateral lower limbs). Participant pain (NRS), depression and anxiety (HADS), quality of life (SF-36), disability (ODI) and total STarT Back scores (SBT) were recorded.
Results: Intrinsic lumbar shape was significantly different between groups; the ‘LDD pain’ group had larger antero-posterior vertebral diameters (p=0.05) and a more even lumbar curvature with smaller L5/S1 intervertebral disc spaces (p=0.01) than the ‘no LDD no pain’ group. Significant differences in postural and kinematic strategy were observed between ‘LDD pain’ and ‘LDD no pain’ groups, particularly during the postural perturbation task (p=0.049-0.001). Depression, anxiety, disability and SBT scores were significantly higher and quality of life lower for the ‘LDD pain’ group when compared with the ‘LDD no pain’ group (p≤0.0001).
Conclusions: This study provides new evidence that intrinsic lumbar shape is associated with LDD and LBP in adults. People with LDD and LBP use different postural and kinematic strategies and have different psychosocial profiles to those without LBP. Future management will need to reflect these biomechanical and psychosocial components.