Do sagittal spinal curvature and back extensor endurance correlate with gait and balance measures in people with degenerative spinal conditions?

Abstract

The aim was to investigate the relationship between sagittal spinal curvature and endurance with dynamic balance and gait in people with symptomatic degenerative spinal conditions. Methods: In this cohort study, participants were enrolled if they had symptomatic osteoporosis (OP) or lumbar spinal stenosis (LSS). Outcomes measured were thoracic kyphosis, lumbar lordosis, kyphosis percentage, Timed Loaded Standing (TLS), Four Square Step Test (FSST), Two minute walk test (2MWT), gait speed, Activities of Balance Confidence (ABC) scale, and Modified Gait Efficacy Score (mGES). Descriptive statistics and correlation analyses were performed. Parametric and non-parametric correlation analyses of spinal curvature and endurance outcomes with balance and gait outcomes were conducted in the group as a whole and in subgroups based on the primary spinal condition. Results: Of 41 participants, 19 had a primary spinal condition of osteoporosis and 22 had lumbar spinal stenosis. The mean (SD) age was 74.0 (7.4) years, BMI was 27.44 (5.30) kg/m2, 27 participants were female, and 44% of participants reported one or more falls in the previous year. There were weak to null correlations between spinal curvature characteristics and all gait and balance measures, and there were moderate correlations between higher back extensor endurance (TLS) and faster gait speed (rs = 0.527), higher 2MWT (rs = 0.560), better FSST (rs = −0.327), higher ABC (rs = 0.316) and higher mGES (rs = 0.317) scores. When separating the group by primary spinal condition, the same relationships with TLS remained, but moderate correlations involving spinal curvature were shown within the OP subgroup, where better dynamic balance (FSST) correlated with increased thoracic kyphosis (rs = -0.416) and lumbar lordosis (rs = −0.424), and increased kyphosis percentage correlated with lower mGES scores (r = −0.429). Conclusion(s): The results suggest that back extensor endurance has a stronger correlational relationship with both performance-based and self-reported gait and balance outcomes compared to sagittal spine curvature, regardless of the spinal condition. However, when anlaysed separately, a correlative relationship between spinal curvature and dynamic balance did emerge in the OP subgroup where the same was not seen in the LSS subgroup. These subgroup findings suggest either the limited impact of spinal curvature in people with LSS or the dominance of other LSS symptoms masking a relationship between spinal curvature and gait and balance measures. Future research should be conducted on a larger sample to explore these correlations and expand to causal relationships. Impact: The findings from this study are foundational for further research to magnify the specific relationships between spinal characteristics and physical function in people with specific symptomatic spinal conditions. A more in-depth clinical description could help inform targeted physiotherapy rehabilitation and interventions in these patient groups.