Background: CBT was proposed as a new trajectory that can improve the fixation of pedicle screws in response to screw loosening in osteoporotic patients. CBT involves a medial-to-lateral direction and a caudocephalad path aiming at maximizing thread contact with higher-density bone with a final aim of this track to improve the adhesion of the screws in osteoporotic vertebrae and to prevent instrumentation failure. However, some studies revealed contradictory findings concerning its effectiveness. Aim of the Work: A systematic review discussing cortical bone trajectory in posterior lumber fixation. Methods: This systematic review consisted of 4 steps, including a systematic search of the literature (Step 1), selection of studies (Step 2), recording of study characteristics (Step 3) and extraction of data on clinical outcomes (Step 4). Results: Literature search and filtration yielded 22 studies (six retrospective reviews, seven prospective, two comparative with historical control group, five systematic reviews, two systematic reviews with meta-analysis).
Conclusion: Review of the enrolled studies confirmed that CBT is a safe, plausible alternative modality to the traditional pedicle screw in posterior lumbar fixation. The use of CBT was associated with some complications; yet their incidence was found to be lower, when compared with the traditional pedicle screw, in the majority of the included studies. However, these studies use different techniques, different screw length and diameter and outcome measures. That is why CBT is recommended as a safe alternative of traditional screw in posterior lumbar fixation and further studies using standardized protocols are needed to confirm findings of the current study.