## 1 Introduction  
Cervical spondylosis, arising from the degeneration of the cervical intervertebral disc and its secondary changes, manifests as clinical symptoms and signs when the adjacent structures such as nerve roots, spinal cord, blood vessels, and esophagus are stimulated or compressed by the degenerated disc [1]. As a prevalent health issue in contemporary society, its current situation is alarming. With the acceleration of modern life rhythms and changes in work patterns, factors such as prolonged maintenance of poor posture, lack of exercise, and aging have collectively contributed to the annual increase in the incidence of cervical diseases [2]. According to epidemiological statistics, the incidence rate of cervical spondylis is approximately 10% among people over 30 years old, 25% among those aged 40 to 50, and exceeds 50% among middle-aged and elderly individuals aged 50 to 70 [3]. This situation not only severely impacts patients' quality of life but also imposes tremendous pressure on societal medical resources. Among the various treatment methods for cervical diseases, total disc replacement (TDR) has gradually emerged as one of the primary treatment modalities due to its effectiveness in restoring spinal function, alleviating pain, and improving patients' quality of life [4; 5; 6]. TDR surgery still faces some significant issues in practical application, among which the material selection and molding method of the core artificial intervertebral disc product are key factors restricting its further development. Currently, there is a wide variety of artificial intervertebral disc materials available, but different materials exhibit marked differences in mechanical properties, biocompatibility, wear resistance, and other aspects, making it challenging to find an ideal material that meets all requirements [7]. The artificial intervertebral disc materials on the market include metals, ceramics, polymers, etc., among which polycarbonate-based polyurethane (PCU) is highly favored due to its excellent biocompatibility, wear resistance, and elasticity [8; 9; 10; 11]. However, PCU materials of different hardness demonstrate varying mechanical properties and long-term stability when used in artificial intervertebral discs. PCU materials with higher hardness may suffer from issues such as stress concentration and material fatigue due to excessive stiffness, while those with lower hardness may lead to deformation and failure of the artificial intervertebral disc due to insufficient support [12; 13]. Therefore, finding the optimal balance among PCU materials of different hardness is an urgent issue that needs to be addressed. Due to the wide range of properties exhibited by polyurethane materials, they hold potential applications in numerous medical scenarios, such as medical catheters, heart valves, and artificial joints. To better meet the specific requirements of different medical applications, researchers employ various methods to modify polyurethane materials and alter their properties. For instance, some researchers can enhance the stiffness and tensile strength while reducing the cost of nanocomposites [14], or develop tailored strategies to functionalize solid surfaces with other materials through isocyanate-polyon reactivity [15]. If the properties of the PCU in this study deviate significantly from those of natural intervertebral discs, further adjustments to the material's properties will be considered to meet the requirements of the intervertebral disc field. Meanwhile, the choice of molding technique also exerts a significant influence on the performance of artificial intervertebral discs. Although traditional molding methods such as injection molding and hot pressing are technologically mature, they have limitations in terms of mold cost and consistency, making it difficult to meet the manufacturing requirements for high-precision artificial intervertebral discs [16].