Magnitude of Dural Tube Compression Still Does Not Show a Predictive Value for Symptomatic Lumbar Spinal Stenosis for Six-Year Follow-Up: A Longitudinal Observation Study in the Community

Background: Lumbar spinal stenosis (LSS) is a clinical syndrome based on anatomic narrowing of the spinal canal. It is well known that anatomic narrowing of the spinal canal is essential for manifestation, but not all of them cause symptoms. There are many studies assessing the relationship between dural tube compression on MRI and clinical symptoms; however, most of them are cross-sectional. The purpose of this study was to reveal the magnitude of dural tube compression's influence on the presence or development of LSS symptoms at the six-year follow-up and the occurrence of surgery during the follow-up period or not in the community setting. Methods: This was a longitudinal observational study of 459 participants who were assessed for typical LSS symptoms, and whose Roland-Morris Disability Questionnaire and numerical rating scale of leg pain and numbness was recorded using a questionnaire and conventional MRI of the lumbar spine. Typical LSS symptoms were judged using an LSS diagnostic support tool, which was a self-administered, self-reported history questionnaire (LSS-SSHQ). After six years, 232 subjects (follow-up rate 50.5%) were followed-up with typical LSS symptoms using LSS-SSHQ by mail. The relationship between the magnitude of dural tube compression evaluated by dural tube cross-sectional area (DCSA) in the initial assessment and the time course of typical LSS symptoms for the six-year duration were analyzed. In addition, predictors of the presence of typical LSS symptoms at the six-year follow-up were assessed. Furthermore, we investigated the relationship between typical LSS symptoms and DCSA during the initial assessment of patients who underwent surgery during the follow-up period. A multivariate logistic regression analysis was performed for statistical analysis. Results: (1) Severe dural tube compression did not show that LSS symptoms continued after six years. (2) Severe dural tube compression could not detect development of LSS-symptoms and surgery during the six-year period. Conclusion: Severe dural tube compression could not detect typical LSS symptom development and occurrence of surgery during the six-year period.