Anchorage of annulus fibrosus within the vertebral endplate with reference to disc herniation

Abstract

The branching of annulus collagen fiber bundles within the endplates increases the interface area with surrounding matrix, reducing shear stresses and (probably) increasing strength. Calcification may also increase strength. These observations can explain why disc herniations often contain cartilage and bone fragments from the endplate.

Tidemark Avulsions are a Predominant Form of Endplate Irregularity

“…In the central portion of the disc, the cartilage endplate is mainly uncalcified hyaline cartilage, and the tidemark joins the hyaline cartilage and a very thin or indiscernible layer of calcified cartilage (Figure 7). 6,18 Our observation that annulus fibers change direction upon crossing the tidemark agrees with previous observations. 17,6…”

“…Unfortunately, clinical classification of endplate damage is hindered by the use of different terminology to describe a single type of endplate irregularity; for example, separations at the annulus-vertebra interface have been described as “avulsions,” “cartilaginous herniations,” and “endplate junction failures.” 1–3,6–9 Conversely, the same term is often used to describe two or more different types of endplate irregularities; for example, nodes with traumatic expulsion of disc material vs. nodes showing more erosive morphologies are both termed “Schmorl’s nodes,” 10,11 despite evidence suggesting that they have very different etiologies. 12 Another example is the use of the term “rim lesion” to describe both bony lesions and annular lesions near the endplate junction.…”

Staying connected: structural integration at the intervertebral disc–vertebra interface of human lumbar spines

“…However, in comparison to sheep, the AF lamellae in these human specimens were not as uniformly distributed, but branching of individual, in-plane AF lamellae was observed at the AF-CEP interface, similar to that seen in the ovine spine [29] and in herniated human IVDs [15]. This mechanism increases the attachment area between the two structures and is likely to enhance the tensile stress that can be sustained at this junction helping to resist detachment.…”

Preparation and Characterization of an Optimized Meniscal Extracellular Matrix Scaffold for Meniscus Transplantation

“…All mechanical tests were performed using a model Z2.5 computer-controlled test machine (Zwick/Roell, Ulm, Germany) as we described previously (Zhao et al, 2009;Junhui et al, 2015). Mechanical uniaxial tensile tests were conducted to calculate the tensile initial elastic modulus, elastic modulus, transition stress, transition strain, and ultimate tensile strength of NM and DM.…”