Redefining lumbar spinal stenosis as a developmental syndrome: an MRI-based multivariate analysis of findings in 709 patients throughout the 16- to 82-year age spectrum

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Using an imaging-based prospective comparative study of 709 eligible patients that was designed to assess lumbar spinal stenosis (LSS) in the ages between 16 and 82 years, the authors aimed to determine whether they could formulate radiological structural differences between the developmental and degenerative types of LSS.


MRI structural changes were prospectively reviewed from 2 age cohorts of patients: those who presented clinically before the age of 60 years and those who presented at 60 years or older. Categorical degeneration variables at L1–S1 segments were compared. A multivariate comparative analysis of global radiographic degenerative variables and spinal dimensions was conducted in both cohorts. The age at presentation was correlated as a covariable.


A multivariate analysis demonstrated no significant between-groups differences in spinal canal dimensions and stenosis grades in any segments after age was adjusted for. There were no significant variances between the 2 cohorts in global degenerative variables, except at the L4–5 and L5–S1 segments, but with only small effect sizes. Age-related degeneration was found in the upper lumbar segments (L1–4) more than the lower lumbar segments (L4–S1). These findings challenge the notion that stenosis at L4–5 and L5–S1 is mainly associated with degenerative LSS.


Integration of all the morphometric and qualitative characteristics of the 2 LSS cohorts provides evidence for a developmental background for LSS. Based on these findings the authors propose the concept of LSS as a developmental syndrome with superimposed degenerative changes. Further studies can be conducted to clarify the clinical definition of LSS and appropriate management approaches.

ABBREVIATIONS BCSA = vertebral body cross-sectional area; CCSA = spinal canal cross-sectional area; LSS = lumbar spinal stenosis; TDSS = total degenerative scale score.

Article Information

Correspondence Edward C. Benzel: Cleveland Clinic, Cleveland, OH.

INCLUDE WHEN CITING Published online September 14, 2018; DOI: 10.3171/2018.5.SPINE18100.

Disclosures The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

© AANS, except where prohibited by US copyright law.



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    Sagittal T2-weighted MR image showing the measurement of anteroposterior spinal canal diameter (APC) and anteroposterior vertebral body diameter (APB).

  • View in gallery

    Axial MRI (T2-weighted) detailing lumbar spinal canal variables tested. A: Anteroposterior spinal canal length (APCa)/anteroposterior vertebral body length (APBa). B: Transverse spinal canal width (TCW)/transverse vertebral body width (TBW). C: Spinal canal cross-sectional area (CCSA)/vertebral body cross-sectional area (BCSA) with thecal sac cross-sectional area (TCSA)/CCSA. D: Interlaminar angle.





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