Purpose: Degenerative spinal conditions, including disc degeneration (DD), Schmorl nodes (SN), and endplate signal changes (ESC), are pervasive age-associated phenomena that critically affect spinal health. The obscurity surrounding ESC stems from its elusive a etiology, a parameter thought to herald morphological shifts in spinal degeneration, and conjectured to be linked to DD. Similarly, the role of SN, despite being genetically determined and correlated with DD in certain contexts. However, the limitations of prior investigations about the association between ESC, SN and DD, including discordant assessment methodologies in the only lumbar region and constrained sample sizes, make the true nature of this association unclear. This study examined the prevalence, distribution, and correlation of DD, SN, and ESC across the entire spine in a population-based cohort.
Methods: The Wakayama Spine Study included 975 participants (324 men, mean age 67.2 years; 651 women, mean age 66.0 years). Magnetic resonance imaging (MRI) was used to evaluate the intervertebral space from L1/2 to L5/S1. DD was classified using Pfirrmann's system, ESC was identified by diffuse high-intensity signal changes on the endplates, and SN was defined as a herniation pit with a hypointense signal. The correlations among these factors were examined.
Results: Prevalence of ≥1 SN over the entire spine was 71% in men and 77% in women, while prevalence of ≥1 ESC was 57.9% in men and 56.3% in women. Positive linear correlations were observed between SN and DD (r = 0.41) and ESC and DD (r = 0.40), but weak correlations were found between SN and ESC (r = 0.29).
Discussion: The prevalence and distribution of SN and ESC over the entire spine were observed, and correlations between SN, ESC, and DD were established. This population-based cohort study provides a comprehensive analysis of these factors.