Bone density-optimized pedicle screw planning enhances mechanical stability.

PURPOSE: This study aimed to evaluate whether bone density-optimized (BDO) pedicle screw trajectories improve screw stability compared to standard trajectories in spinal fusion surgery. The central research question was whether preoperative planning based on bone mineral density (BMD) can enhance screw fixation strength and potentially reduce the risk of loosening.

METHODS

A biomechanical cadaveric study was conducted using thirty human vertebrae. Each vertebra was instrumented with one pedicle screw using a standard trajectory and another using a BDO trajectory. Two trajectory types were tested: traditional trajectory (TT) and cortical bone trajectory (CBT). Screw stability was assessed by mechanical pullout testing, measuring the ultimate force required to extract each screw.

RESULTS

BDO trajectories significantly improved screw pullout strength in both trajectory types. For TT screws, the median increase in pullout force was 43.1% (interquartile range [IQR]: 10.1%, 108.3%; p =  0.004). For CBT screws, the median increase was 37.0% (IQR: -1.5%, 122.6%; p = 0.034).

CONCLUSION

Bone density-optimized pedicle screw trajectories significantly enhance screw fixation strength in both traditional and cortical trajectories. These findings support the use of personalized, BMD-informed surgical planning to improve spinal fusion outcomes and reduce the incidence of screw loosening.