X-ray image of Schmorl's nodes in the lumbar spine
|Classification and external resources|
These are protrusions of disc material into the surface of the vertebral body, which may contact the marrow of the vertebra and lead to inflammation. The protrusions are also associated with necrosis of the vertebral bone and the question of whether these protrusions and inflammation cause the necrosis, or whether the cartilage migrates into areas that have become necrotic due to other conditions, is under investigation.
They may or may not be symptomatic, and their etiological significance for back pain is controversial. Williams and colleagues note that this relationship may be due to lumbar disc disease, as the two commonly occur simultaneously.
Schmorl's nodes can be detected with x-ray, although they can be imaged better by CT or MRI. Schmorl's Nodes are considered to be vertical disc herniations through the cartilaginous vertebral body endplates. They can sometimes be seen radiographically, however they are more often seen on MRI, even when not visible on plain film x-ray. They may or may not be symptomatic, and their etiological significance for back pain is controversial. In a study in Spine by Hamanishi, et al., Schmorl's nodes were observed on MRI in 19% of 400 patients with back pain, and in only 9% of an asymptomatic control group. The authors concluded that Schmorl's nodes are areas of "vertical disc herniation" through areas of weakness in the endplate.
Schmorl's nodes are fairly common, especially with minor degeneration of the aging spine, but they are also seen in younger spines. Schmorl's nodes often cause no symptoms, but may simply reflect that "wear and tear" of the spine has occurred over time; they may also reflect that bone strength was at one time somewhat compromised, perhaps due to a vitamin D deficiency although this has yet to be confirmed with studies,or if heavy lifting is done at a young age before the vertebral bodies are completely ossified such as in young farm workers. There is also a strong heritability of Schmorl's Nodes (>70%).While often non-complicating, Schmorl's nodes also tend to occur more often in cases of spinal deformity, specifically Scheuermann's disease. These defects are caused when the vertebra loses its normal function and is not moving/hypomobile/subluxated. During this time the forces normally distributed by the nucleus pulposis (the incompressible gelatinous center of the intervertebral disc) are concentrated in a certain area causing endplates to deform in a concave manner.
- synd/2377 at Who Named It?
- Williams, F. M. K.; N. J. MANEK; P. N. SAMBROOK; T. D. SPECTOR; A. J. MACGREGOR (June 2007). "Schmorl’s Nodes: Common, highly heritable, and related to Lumbar Disc Disease". Arthritis & Rheumatism (Arthritis Care & Research) 57 (5). doi:10.1002/art.22789.
- MedFriendly.com: Schmorl’s nodule
- McFadden KD, Taylor JR (1989). "End-plate lesions of the lumbar spine". Spine 14 (8): 867–869. doi:10.1097/00007632-198908000-00017. PMID 2781398.
- Peng B, Wu W, Hou S, Shang W, Wang X, Yang Y (2003). "The pathogenesis of Schmorl's nodes". The Journal of bone and joint surgery. British volume 85 (6): 879–82. PMID 12931811.
- Takahashi K, Miyazaki T, Ohnari H, Takino T, Tomita K (1995). "Schmorl's nodes and low-back pain. Analysis of magnetic resonance imaging findings in symptomatic and asymptomatic individuals". European spine journal 4 (1): 56–9. doi:10.1007/bf00298420. PMID 7749909.
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