Clinical implications of lumbar developmental spinal stenosis – back pain, radicular leg pain and disability with 2206 subjects

Abstract

Introduction: Low back pain (LBP) and radiating leg pain are two common health problems around the world. Lumbar developmental spinal stenosis (DSS) may play an important role in pain generation. It is described as pre-existing narrowed vertebral canals at multiple lumbar levels with earlier onset of neurological compromise. Therefore, this study was designed to assess the interaction of DSS and different radiological phenotypes in producing LBP, radiating leg pain and disability. Material and Methods: This was a prospective cohort of 2206 Chinese subjects with clinical assessments and matched L1-S1 axial and sagittal MRI. Information related to LBP and radiating leg pain by VAS was recorded by age of onset, any pain experienced in the past month (30 days) and year (365 days). Demographics including age, gender, height, weight and body mass index (BMI), smoking habit, exercise and occupation were obtained and calculated. ODI, SF-36 and Roland-Morris Disability Questionnaire were obtained. Two independent investigators with excellent interobserver and intraobserver reliability measured the axial anteroposterior (AP) vertebral canal diameter, facet joint angulation and tropism, any disc herniation, Pfirrmann grading, endplate irregularity, high intensity zone, radial tear, spondylolisthesis, Modic change and anterior marrow change. DSS was classified as axial AP vertebral canal diameters below the cut-offs at 3 or more levels: L1 < 19 mm, L2 < 19 mm, L3 < 18 mm, L4 < 18 mm, L5 < 18 mm, S1 < 16 mm. Presence of DSS or not was used to dichotomize subjects and multivariate logistic regression models studied the four clinical outcomes of LBP and radiating leg pain in the past month and year. Results: Of the 2206 subjects, 153 had DSS. Mean age was 51.9 years with mean BMI of 23.7. There were 38.4% males and 61.6% females. 72.1% subjects had LBP in the past year and 56.7% had LBP in the past month. 41.0% subjects had radicular leg pain in the past year and 30.5% had radicular leg pain in the past month. DSS subjects had worse LBP and higher incidence of radiating leg pain in the past month and year, and worse outcome scores, higher disc herniation and degeneration score. No significant associations were observed between disc degeneration and herniation, facet joint morphology, high intensity zones, and Modic changes with LBP and leg pain. For LBP, spondylolisthesis was found as significant risk factors for our model. Subjects with spondylolisthesis had 1.526 (95% CI = 1.004-2.322; P = .048) times higher odds of LBP in the past month and 1.762 (95% CI = 1.047-2.963; P = .033) times higher odds of LBP in the past year. After adjusting for gender, age, BMI and workload, our model found that subjects with DSS had higher odds of radiating leg pain in the past month (adjusted OR = 1.439; 95% CI = 1.004-2.063; P = .048) and past year (adjusted OR=1.811; 95% CI = 1.262-2.600; P = .001). Conclusion: Based on this large-scale prospective cohort, we identified risk factors for acute and chronic LBP and radiating leg pain. Spondylolisthesis is a main risk factor for both acute and chronic LBP, while subjects with DSS and SNs had higher risks of acute and chronic radiating leg pain. The impact of our findings relates to prognostication and management outcomes.