Bionic Intervertebral Disc: Anisotropic Fibers for Vertebral Motion

The patent applies local quality by designing the fibrous ring with variable stiffness through different collagen fiber arrangement patterns in different regions. The anterior region has a first arrangement pattern with different orientation characteristics compared to the posterior region's second arrangement pattern, creating spatially varying mechanical properties that match physiological movement requirements while maintaining overall structural integrity.

The patent implements asymmetry by introducing asymmetric collagen fiber inclination angles in the fibrous ring structure. The anterior inclination angle differs from the posterior inclination angle, creating an asymmetric mechanical response that replicates the biological intervertebral disc's ability to handle different loading conditions in different directions during physiological movement.

The patent extends local quality to the transition zone by introducing a third arrangement pattern for collagen fibers in this specific region, which differs from both the anterior and posterior regions. This creates a gradient of structural complexity that mirrors the biological transition zone's role in gradually transitioning between the nucleus pulposus and fibrous ring, enhancing mechanical regulation under low loads.

The patent segments the fibrous ring into distinct regions (anterior, posterior, and transition zone) with different collagen fiber arrangement patterns. Each segment has specific inclination angles and structural characteristics that contribute to the overall mechanical anisotropy, allowing the structure to handle different physiological loading conditions effectively.

The patent employs composite materials by combining different types of fibers (collagen fibers with varying orientations and elastic modulus values, elastic fibers, and proteoglycan aggregates) within the fibrous ring and transition zone. This composite structure creates mechanical anisotropy that prevents sinking and dislocation while maintaining manufacturability through established biomaterials.

The patent applies local quality at the material level by using collagen fibers with different elastic modulus values and arrangement patterns in different regions. The anterior region has different fiber composition compared to the posterior region, creating spatially varying mechanical properties that prevent sinking and dislocation while remaining compatible with current manufacturing capabilities.