Association of oxidative stress with postural control and functional outcomes in lumbar degenerative disease: An exploratory cross-sectional study.

Abstract

Lumbar degenerative disease involves age-related structural and functional changes in the spine, often leading to impaired motor function and decreased quality of life. Although oxidative stress may influence muscle function, its relationship with dynamic postural control remains unclear. This exploratory cross-sectional study enrolled 46 Japanese patients (mean age 60.5 ± 16.3 years) undergoing posterior lumbar spine surgery for lumbar degenerative disease, including lumbar spinal stenosis and lumbar disc herniation. Trunk flexion and extension during sit-to-stand movements were assessed using three-dimensional motion analysis. Systemic oxidative stress was evaluated using urinary 8-hydroxy-2'-deoxyguanosine in 34 patients, and local oxidative stress was assessed by dihydroethidium staining of the lumbar multifidus muscle in 32 patients. Associations among dynamic trunk parameters, oxidative stress markers, and Oswestry Disability Index scores were examined using linear regression analyses. Dynamic trunk extension was significantly reduced during the sit-to-stand task compared with the static baseline posture (p < 0.001, r = 0.794). In multivariable analyses, higher low back pain intensity and reduced walking capacity were independently associated with worse Oswestry Disability Index scores, whereas trunk extension was not a primary determinant in the main model but showed a significant association in sensitivity analyses. Higher urinary 8-hydroxy-2'-deoxyguanosine levels and greater dihydroethidium intensity were associated with reduced trunk extension. These findings suggest a potential link between oxidative stress and impaired dynamic trunk extension. In patients with lumbar degenerative disease, disability during daily activities is primarily associated with pain and walking capacity. Dynamic trunk extension may represent an important postural strategy rather than a direct determinant of disability. Oxidative stress was associated with reduced trunk extension in exploratory sub-analyses, warranting further investigation in longitudinal or interventional studies.