The epidemiology of Schmorl's nodes and their correlation to radiographic degeneration in 4,151 subjects.

Purpose: Schmorl's nodes (SNs) are commonly seen in vertebral imaging of the normal adult population referred for different reasons and are duly noted by the radiologist. However, little is known about their etiology: either SNs are perceived as largely inert developmental or congenital herniations of disc tissue into weak areas of the vertebral end-plates, or they are perceived as a common pathological pathway of different adverse and general factors such as malignancy, trauma, infection, osteoporosis, Paget's disease and so forth. A commonly accepted morphological definition of what precisely constitute SNs does not exist, and consequently prevalences vary wildly in the literature. In the present study of 4,151 standardized lateral radiographs of the lumbar spine in an adult, Caucasian population between 22 and 93 years (median age 63 years, M 1,533, W 2,618).

Methods: We investigated prevalence, distribution and epidemiologic relationships of SNs.

Results: SNs occur primarily in the upper part of the lumbar spine, and usually there are multiple lesions in the same individual. We could not establish any significant correlation between SNs and gender, age, BMI, height, weight or occupational exposure for heavy lifting. The overall prevalence was 3.8%. We did not find any significant correlations between SNs and overall degeneration of the lumbar spine.

Conclusion: We found a prevalence of SNs in the lower end of the spectrum than hitherto reported.