Anatomical research on strength of screw track fixation in novel cortical bone trajectory for osteoporosis lumbar spine

Objectives: The cortical bone screw has good internal fixation effect on osteoporotic bone. In order to further increase the strength of screw track fixation in cortical bone trajectory, this study introduced a modified technique with novel insertion point and angle for cortical bone screw placement. Methods: Cortical bone screws were placed in four dry and six wet and intact lumbar specimens according to the modified technique. A total of 100 trajectories in specimens were confirmed by X-ray and CT scan to evaluate the safety, accuracy and practicability of screw fixation. The successful rate was 95% (38/40) in four dry specimens, and 88.7% (53/60) in six wet specimens. Conclusion: This study showed that the novel trajectory could be fixed more closely with cortical bone compared to traditional cortical bone trajectory technique, and thus it may reduce the surgical exposure to the elders and help them to recover quickly after the operation.