Vertebral Endplate Structural Defects: Measurement, Prevalence and Associated Factors
Abstract
Objective: To synthesize current knowledge on the association of endplate structural defects (EPSD) with back pain (BP), improve EPSD measurement, and investigate EPSD prevalence, distribution, and association with age and body mass index (BMI).
Methods: In study 1, a systematic review was conducted on five databases for studies reporting on the association between EPSD and BP. Studies 2 and 3 used CTs and mCTs of 19 embalmed cadavers to examine the diagnostic accuracy of common EPSD assessment methods, and to develop and validate a novel method. Study 4 used the novel method on 200 adult males’ MRI to estimate EPSD prevalence, distribution, and association with age and BMI.
Results: Data from the 26 studies (11,027 subjects) on the association of EPSD with BP included in the systematic review were not pooled due to heterogeneity (I2=73%) relating to measurements and nomenclature, except for erosion, sclerosis and Schmorl’s nodes (OR:1.53-1326). The common EPSD assessment methods had a sensitivity of 70.9%-79.5% and specificity of 57.5%-79.1% and certain phenotypes were absent or misclassified (e.g., wavy/irregular and erosion). A novel method was therefore developed, consisting of definitions and atlases of six EPSD phenotypes with good inter-rater reliability for EPSD presence (K=0.65-0.68) and improved sensitivity (71.0%-79.0%) and specificity (77.0%-87.0%). Inter-rater reliability for specific phenotypes was fair (K=0.52-0.55). Using the novel method, there was a high prevalence of EPSDs (45.6%), with erosion (17.6%) being the most common phenotype. EPSD occurred more in the upper lumbar regions (c2= 41.68) and on the caudal endplates (c2=9.28) and were associated with greater age (OR:1.02, 95%CI:1.01-1.03) but not BMI (OR:1.00, 95%CI:0.98-1.03). Furthermore, age was associated with focal defects (OR:1.02, 95%CI:1.00-1.03) and erosion (OR:1.03, 95%CI: 1.01-1.04), while BMI was only associated with corner defects (OR:1.15, 95%CI:1.03-1.30).
Conclusion: The lack of standardized methods has impeded the understanding of EPSD and BP. Using a novel standardized assessment method, a developmental origin of Schmorl’s nodes is supported, and focal and erosive defects appear degenerative in nature, while corner defects appear to have a biomechanical origin. The project has opened a new avenue for measurement and further understanding of EPSD and their etiology and clinical significance.