4 pedicle screw mono-segment versus 6 pedicle screw short-segment fixation in the treatment of thoracolumbar endplate fractures: finite element analysis and clinical follow-up

Finite element analysis and prediction based on specific models: Both 4 pedicle screw mono-segment fixation and 6 pedicle screw short-segment fixation are effective methods for treating thoracolumbar burst fractures of the spine. The 4 pedicle screw mono-segment fixation may be suitable for patients with normal bone mineral density and mild-to-moderate fractures, with advantages of preserving spinal mobility and reducing the risk of adjacent segment degeneration. The 6 pedicle screw short-segment fixation has a wider application range, and its advantages lie in better stability and stress dispersion. For upper endplate fractures, the adjacent segment at the proximal end is the stress concentration area, and the proximal screws bear the maximum stress; in contrast, for lower endplate fractures, the adjacent segment at the distal end is the stress concentration area, and the distal screws bear the maximum stress. The stability gap between 4 pedicle screw mono-segment fixation and 6 pedicle screw short-segment fixation is smaller in lower endplate fractures than in upper endplate fractures. Compared with upper endplate fractures, lower endplate fractures show better overall performance and may have a better prognosis. However, different finite element models may be required in the future to reduce the impact of individual differences. 2. Clinical outcomes mainly for upper endplate fractures: For mild-to-moderate fractures, the 4 pedicle screw mono-segment fixation achieves the same reduction effect as the 6 pedicle screw short-segment fixation both immediately after surgery and during long-term internal fixation removal. Moreover, it has advantages such as shorter operation time, smaller incision, less blood loss, earlier weight-bearing time, shorter hospital stay, less early postoperative pain, and faster functional recovery. However, more cases of lower endplate fractures may need to be collected in the future for further verification.