Impact of spinal imbalance and BMI on lumbar spinal canal stenosis determined by a diagnostic support tool: cohort study in community-living people

Abstract

The Japanese Society for Spine Surgery and Related Research (JSSR) developed a diagnostic support tool (score range −2 to 16) for lumbar spinal canal stenosis (LSS). It is well known that patients with LSS have a forward-bending posture while walking. We could find only one study which examined sagittal alignment of LSS patients. The objectives of this study were to screen community-living people with LSS, and to investigate the association between LSS and spinal sagittal alignment, range of motion (ROM), and other spinal or physical factors. We enrolled 286 subjects ≥50 years old in the study. We regarded those with a JSSR diagnostic risk score ≥7 as having LSS. We measured and evaluated lateral lumbar radiographs, sagittal parameters, sagittal balance, and spinal mobility as determined with SpinalMouse®, back muscle strength (BMS), and body mass index (BMI). Spinal inclination angle (SIA) was used as an index of sagittal balance. Multivariate logistic regression analysis indicated that increased BMI (OR 1.121, p < 0.05) and SIA (OR 1.144, p < 0.05) were important relevant factors for LSS. BMI had significant positive correlations with SIA (r = 0.214), and thoracic and lumbar kyphosis angles (r = 0.283, 0.131), and negative correlations with sacral slope angle (r = −0.166), and lumbar and total spinal ROMs (r = −0.270, −0.166). SIA had significant positive correlations with age (r = 0.334), BMI (r = 0.214) and lumbar kyphosis angle (r = 0.525), and negative correlations with BMS (r = −0.268), and lumbar and total spinal ROMs (r = −0.184, −0.171). Increased SIA and BMI might be the most relevant risk factors for LSS.