Purpose: To investigate the frequency and characteristics of Schmorl nodes in an elderly population and to correlate these findings with degenerative spinal changes.
Materials and methods: Cadaveric thoracic and lumbar spines were removed at autopsy (mean age at death, 68.2 years; range, 43-93 years). Parasagittal sections of approximately 5-mm thickness were obtained and radiographed. At each of 3,300 endplates from T1 to L5, the presence of Schmorl nodes was noted. Vertebral endplate contour was analyzed, and abnormalities of the discovertebral junction were noted. The height of each interspace was measured, and the presence or absence of vacuum phenomena and spondylosis was recorded.
Results: Schmorl nodes were found in 58 specimens and were multiple in 41. Of 3,300 vertebral endplates, 225 revealed Schmorl nodes: 88 cranial and 137 caudal. More than 182 were between T7 and L2. Schmorl nodes correlated with disk space loss (P <.001) but not with evidence of advanced disk degeneration: marked disk space loss (P =.53), vacuum phenomena (P =.82), or discogenic sclerosis or erosion (P =.35). Schmorl nodes were associated with claw (P <.001) but not traction (P =.72) osteophytes. Straight (P <.001) and fractured (P <.001) vertebral endplates were associated with Schmorl nodes.
Conclusion: Schmorl nodes are common in the spines in an elderly population, with a frequency similar to that in a younger population. Schmorl nodes are associated with moderate but not advanced degenerative changes. Geometric observations regarding the vertebral endplates support the concept that Schmorl nodes are caused by an abnormality of the discovertebral junction.