Significance of cartilage endplate within herniated disc tissue
Polly Lama, Uruj Zehra, Christian Balkovec, Henry A. Claireaux, Luke Flower, Ian J. Harding, Patricia Dolan, Michael A. Adams
August 2014, Volume 23, Issue 9, pp 1869 - 1877 Original Article Read Full Article 10.1007/s00586-014-3399-3
First Online: 20 June 2014
Purpose
Disc herniations sometimes contain hyaline cartilage fragments, but their origins and significance are uncertain.
Methods
Herniations were removed surgically from 21 patients (aged 35–74 years) whose main symptom was sciatica (10 patients) or back pain (11 patients). Frozen sections, 5 µm thick, were examined histologically, and antibodies were used to label the matrix-degrading enzyme MMP 1, pro-inflammatory mediator TNFα, and cell proliferation marker Ki-67. Proportions of each tissue type were quantified by image analysis. Cartilage and bone components of the endplate were examined in 7-µm frozen sections from 16 cadaveric spines, aged 61–98 years.
Results
Cartilage fragments were found in 10/21 herniations. They averaged 5.0 mm in length, comprised 25 % of the herniation area, and two had some bone attached. Hyaline cartilage was more common in herniations from patients with sciatica (7/10) than with back pain (3/11, P = 0.050), and the area (%) of the herniation occupied by the cartilage was greater in sciatica patients (P
Conclusion
Disc herniations often include hyaline cartilage pulled from the vertebral endplates. Cartilage fragments show little swelling or proteoglycan loss, and may be slow to resorb, increasing the risk of persisting sciatica. Loss of cartilage will increase endplate permeability, facilitating endplate inflammation and disc infection.
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