Postoperative Low Back Pain after Posterior Lumbar Interbody Fusion Surgery Using Cortical Bone Trajectory Screws

Study Design: Retrospective analysis of a case series of prospectively collected data. Purpose: To compare clinical and radiological outcomes between two posterior lumbar interbody fusion techniques: cortical bone trajectory (CBT) and traditional pedicle screw (PS). Overview of Literature: Biomechanical studies have revealed the benefits of the CBT technique. However, clinical evidence obtained from the direct comparison of outcomes between CBT and PS is limited. Methods: We retrospectively investigated 104 patients who had undergone posterior lumbar interbody fusion using CBT or PS. Clinical symptoms were evaluated and compared between CBT and PS using the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and Visual Analog Scale (VAS) before and 1 year after surgery. Spinal fusion status was assessed by multi-planar reconstruction computed tomography at 1 year after surgery. Results: The CBT and PS techniques were performed on 36 and 68 patients, respectively. Both CBT- and PS-treated patients exhibited improvement in each subdomain of the JOABPEQ and in the VAS. With regard to postoperative improvement of low back pain, the treatment effect, as assessed by the JOABPEQ, was greater for PS than for CBT. The spinal fusion rate was slightly lower for CBT than for PS, although the difference between them was not significant. The effect of treatment on postoperative low back pain was smaller for CBT than for PS, regardless of whether rigid spinal fusion was achieved. Conclusions: Clinical symptoms and spinal fusion efficiency were not significantly different between CBT and PS except for postoperative improvement in low back pain. The treatment effect on postoperative low back pain was smaller for CBT than for PS.