Patient-Specific Lattice Cage Design for Cervical Spinal Fusion

To propose a patient-specific interbody cage with graded stiffness distributions analogous to the Young's modulus of the cervical spinal bone interface in order to improve mechanical compatibility, promote physiological load sharing, and enhance osseointegration.

A synthetic database of spinal bone Young modulus values was used, incorporating anatomical regions (cervical, thoracic, lumbar) and patient-specific factors (age, bone density, health status). A parametric generative design approach allowed dynamic modification of lattice unit cell geometry to achieve target stiffness values (200-3000 MPa) while preserving structural integrity.

Finite element endplate analysis demonstrated a 30%-50% reduction in stress shielding compared with conventional solid or homogeneous mesh lattices. Additively manufactured prototypes showed tunable stiffness-porosity trade-offs, achieving yield strength ≥150 MPa while supporting osseointegration.

This study demonstrates improved load distribution and reduced risk of cage collapse compared with cadaveric spine data. Integrating computational design, biomechanical compatibility, and additive manufacturing may facilitate the development of patient-specific spinal implants with superior mechanical and biological performance.