Prevalence and distribution of Schmorl node and endplate signal change, and correlation with disc degeneration in a population-based cohort: the Wakayama Spine Study

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. Despite their prevalence, a comprehensive exploration of their distribution and correlations is lacking. 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 C2/3 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. We assessed the prevalence and distribution of SN, ESC, and DD across the entire spine. 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. The prevalence of ESC and SN in the thoracic region was the highest among the three regions in both sexes. Positive linear correlations were observed between the number of SN and DD (r = 0.41, p < 0.001) and the number of ESC and DD (r = 0.40, p < 0.001), but weak correlations were found between the number of SN and ESC (r = 0.29, p < 0.001).

Conclusion: 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.