The Fusion Rate of Cortical Bone Trajectory Screw Fixation and Pedicle Screw Fixations in L4-5 Interbody Fusion: A Retrospective Cohort Study

Abstract

Objective: Although cortical bone trajectory (CBT) screw fixation has been used for several years, the number of studies on its fusion effects is limited. Furthermore, several studies report conflicting outcomes. We aimed to compare the fusion rates and clinical efficacy of CBT screw fixation and pedicle screw (PS) fixation for L4-L5 interbody fusion.

Methods: This study was a retrospective cohort control study. Patients with lumbar degenerative disease who underwent L4-L5 oblique lumbar interbody fusion (OLIF) or posterior decompression using CBT screws between February 2016 and February 2019 were included. Patients in whom PS was used were matched for age, sex, height, weight, and BMI. Record the operation time, blood loss. All enrolled patients underwent lumbar CT imaging at one-year follow-up to evaluate the fusion rate. At the two-year follow-up the visual analogue scale (VAS), Oswestry disability index (ODI), and Japanese Orthopaedic Association scores (JOA) were used to identify symptom improvement. Independent t-test was used for the comparison, and score data were analyzed using the χ² and exact probability tests.

Results: A total of 144 patients with were included. All patients were followed-up postoperatively for 25-36 months (average 32.42 ± 10.55 months). Twenty-eight patients underwent OLIF and CBT screw fixation, 36 underwent OLIF and PS fixation, 32 underwent posterior decompression and CBT screw fixation, and 48 underwent posterior decompression and PS fixation. The fusion rates following CBT screw and PS fixations in OLIF were 92.86% (26/28) and 91.67% (33/36), respectively (P = 1). The fusion rates following CBT screw and PS fixations in posterior decompression were 93.75% (30/32) and 93.75% (45/48), respectively (P > 0.05). Regardless of OLIF or posterior decompression, there were no significant differences in the VAS, ODI, and JOA scores between patients treated with CBT and PS (P > 0.05).

Conclusion: CBT screw fixation can achieve a satisfactory interbody fusion rate with a clinical efficacy similar to that of PS in patients with lumbar degenerative disease, regardless of whether OLIF or posterior decompression was performed.

Keywords: Comparative study; Cortical bone trajectory screw; Interbody fusion; Lumbar degenerative disease; Pedicle screw.

Fig. 1

Follow the flow chart of the above criteria.

Fig. 2

(A, B): Patient's preoperative MRI scan images showing stenosis of the canal at the L4‐L5 level. (C, D): Radiographs obtained at 6 months follow‐up indicating satisfactory internal fixation. (E): CT images obtained at one‐year follow‐up showing satisfactory interbody fusion at L4‐L5. (F): Healed incision of approximately 2 cm length at one‐year follow‐up.