[Biology and mechanobiology of the intervertebral disc : Challenges for regenerative therapies].

The fibrocartilaginous intervertebral discs between the vertebrae give the spine mobility and flexibility. Age and degeneration contribute to tissue changes that affect the composition and structure of the intervertebral discs and can lead to loss of function and back pain. The intervertebral disc cells are responsible for the formation and maintenance of the tissue and are influenced by the physiological load.

[Biomechanics of the intervertebral disc : Consequences of degenerative changes].

The intervertebral disc represents the flexible connection between two adjacent vertebral bodies. Intervertebral discs, therefore, give the spine its enormous range of motion. At the same time, intervertebral discs distribute the load evenly over the bony vertebral bodies to ensure load transfer from the upper body to the pelvis, provide sufficient stability, and absorb shocks during everyday movements as well as under extreme loads.

Papain Injection Creates a Nucleotomy-like Cavity for Testing Gels in Intervertebral Discs.

Biomaterials, such as hydrogels, have an increasingly important role in the development of regenerative approaches for the intervertebral disc. Since animal models usually resist biomaterial injection due to high intradiscal pressure, preclinical testing of the biomechanical performance of biomaterials after implantation remains difficult. Papain reduces the intradiscal pressure, creates cavities within the disc, and allows for biomaterial injections.

Analysis of Intervertebral Disc Degeneration Induced by Endplate Drilling or Needle Puncture in Complement C6-Sufficient and C6-Deficient Rabbits.

Previous studies indicate an implication of the terminal complement complex (TCC) in disc degeneration (DD). To investigate the functional role of TCC in trauma-induced DD in vivo, the model of endplate (EP) drilling was first applied in rabbits using a C6-deficient rabbit strain in which no TCC formation was possible. In parallel the model of needle puncture was investigated.

The Injection of Gels Through an Intact Annulus Maintains Biomechanical Performance without Extrusion Risk.

For autologous-disc-derived chondrocyte transplantation (ADCT) a transglutaminase crosslinked gelatine gel and an albumin hyaluronic acid gel, crosslinked with bis-thio-polyethylene glycol, were injected through a syringe into a degenerated intervertebral disc, where they solidified in situ. This biomechanical in vitro study with lumbar bovine motion segments evaluated disc height changes, motion characteristics in a quasi-static spine loading simulators, and the potential extrusion risk of these biomaterials in a complex dynamic multi-axial loading set-up with 100,000 loading cycles. After the injection and formation of the gel in the center of the nucleus, the disc height increase was about 0.