Microstructural imaging of the cartilaginous endplate in the intervertebral disc.

1 OBJECTIVE: Intervertebral disc (IVD) degeneration is a major risk factor for the development of chronic low back pain (LBP), affecting millions globally, particularly as they age. IVD degeneration can promote inflammation, and reduce spinal stability leading to compression of nerve roots. Research has primarily focused on the annulus fibrosus (AF) or nucleus pulposus (NP), with an unmet need to explore the physiology of the cartilaginous endplate (CEP) and its microstructural assessment in IVD degeneration. Imaging the microstructure of the CEP, a relatively thin layer between the IVD and vertebral body, is challenging. This mini-review discusses advanced imaging methods to capture the microstructure of the CEP.

2 DESIGN: This narrative mini-review explores current methods for in vitro and ex vivo microstructural imaging of the CEP using advanced techniques such as three-dimensional (3D) micro-computed tomography (µCT) and two-dimensional (2D) light microscopy.

3 RESULTS: Advanced imaging techniques can provide detailed visualization of IVD microarchitecture, structural integrity, and degeneration, including CEP structure. Optical light microscopy techniques provide detailed 2D images of the CEP from stained or unstained IVD sections. Imaging the IVD in a 3D modality, such as contrast-enhanced µCT, enables a better understanding of the CEP's microstructural changes in IVD degeneration.

4 CONCLUSIONS: High-resolution 3D imaging of the CEP could be useful for visualizing and quantifying the response of degenerated tissue to experimental therapeutics ex vivo. Moreover, analyzing CEP-driven microstructural degeneration is crucial for developing preclinical anatomical models that spine surgeons can use to test and evaluate medical and therapeutic candidates.