Fracture Patterns of an Osteolytic Hole Involved Lumbar Vertebra, Assessed for a Case Study by Computational Models

Osteolytic vertebrae containing central lesions are associated with a high risk of burst fracture, as the presence of such lesions indicates substantial bone destruction. The present study aimed to investigate fracture patterns in a clinically relevant case of a lumbar vertebra with an osteolytic cavity under various loading conditions using a computational modeling approach. Osteolytic damage progression was simulated through a virtual thermal flux approach, while stiffness degradation was represented using a continuum damage mechanics framework. Potential crack locations within the vertebra were defined based on an established clinical classification, and crack propagation was evaluated using the Virtual Crack Closure Technique (VCCT). The results demonstrated that the mechanical competence and fracture patterns of the osteolytic vertebra were strongly dependent on the intensity of osteolytic damage and the applied loading conditions. The earliest onset of instability occurred under lateral bending loading when the average osteolytic damage reached approximately 50%. Under kyphotic loading, vertical cracks propagated around the osteolytic cavity and could significantly compromise vertebral stability when combined with compressive and bending loads associated with daily activities. Such loading conditions may promote the connection of horizontal endplate cracks with vertical cracks, resulting in a burst fracture pattern. Therefore, vertebrae containing osteolytic cavities should be carefully protected against lateral bending loads during the treatment period, and exposure to heavy loading postures should be strictly avoided. Future studies should investigate the sensitivity of vertebral load-carrying capacity to variations in the size, shape, and location of osteolytic lesions.