# Biomechanical Optimization of Lumbar Fusion Cages with a Porous Design: A Finite Element Analysis
## 4 Discussion
The superior performance of the V-Cage highlights the transformative potential of parametric modeling and additive manufacturing in interbody fusion. Current classic cages often adopt a standardized approach, potentially overlooking individual variations in vertebral anatomy and bone quality [40]. By integrating patient-specific geometry with biomimetic porosity, as demonstrated here and in prior multi-segment implant studies, the V-Cage optimizes both load-bearing capacity and osseointegration. Future advancements could leverage bioactive coatings or degradable materials such as bioresorbable magnesium alloy to further enhance osteoconductivity and implant longevity [41]. Suchinnovations could pave the way for fully personalized spinal implants tailored to individual biomechanical and biological profiles. Due to the complex structure of the lumbar spine, the establishment of the finite element model and the corresponding analysis have certain limitations and can only reflect some movement patterns and biomechanical changes. The FE model was based on the L3-L4 segment of a single, healthy young male volunteer. This idealized model does not account for patient-specific variations or pathological conditions commonly encountered in clinical practice, such as degenerative disk disease, osteoporosis, or deformities. In unhealthy spines, factors like reduced bone mineral density, altered disk height, ligament laxity, and musculature could significantly influence cage stability, stress distribution, and subsidence risk, potentially leading to different biomechanical outcomes compared to those observed here. Therefore, the results should be interpreted as a comparative assessment under idealized conditions [42]. In addition, the simulation represented immediate postoperative conditions and did not capture long-term biological processes like bone ingrowth, remodeling, or implant fatigue [43]. Future studies are warranted to incorporate patient-specific pathological features (e.g., osteoporonic bone properties) and potentially multi-segmental models to provide a more comprehensive biomechanical evaluation relevant to diverse clinical scenarios. Despite these limitations, the current study provides valuable foundational insights into how personalized porous designs influence immediate postoperative biomechanics compared to traditional cages. Nevertheless, the effectiveness of the finite element model in this experiment has been verified and has a certain predictive effect. Validation through in vitro mechanical testing and in vivo animal studies is essential to corroborate these computational predictions. Moreover, the manufacturing complexity and cost of Voronoi-based cages pose translational hurdles, reflecting broader challenges in scaling personalized implants for widespread clinical use [35]. In summary, this study delineates a clear hierarchy among interbody fusion cage designs, with the V-Cage emerging as the most biomechanically advantageous due to its Voronoi-based porous structure. By reducing stress concentrations, enhancing endplate stability, and optimizing segmental kinematics, this design offers a compelling foundation for improving fusion outcomes. These insights advocate for the continued exploration of porous, personalized implants to address the unmet needs of spinal surgery. Future studies should investigate how degenerative conditions, such as osteoporosis, might affect subsidence risk in pathological spine models.