• Different endplate defect types significantly alter stress transmission pathways in the lumbar spine, with marginal defects affecting the lateral annulus and central defects impacting extension load bearing.
• Stress gradient concentration at defect edges indicates potential microdamage risk, highlighting the importance of early detection.
• Angular endplate defects cause significant stress concentration under dynamic loads, potentially accelerating segmental instability and degeneration.
• The study provides biomechanical evidence linking endplate defects to disc degeneration and facet joint damage, aiding clinical risk assessment and prevention.