The comparison of pedicle screw and cortical screw in posterior lumbar interbody fusion: a prospective randomized noninferiority trial.

Background Context: Pedicle screws (PS) offer great benefits in posterior lumbar interbody fusion (PLIF), but several drawbacks of PS, including the risk of superior facet joint violation and muscle injury, have also pointed out. Recently, cortical screws (CS) were invented, which can be placed without the drawbacks associated with PS. However, whether CS in PLIF can provide similar or greater clinical and radiologic outcomes compared to those of PS has not been fully evaluated in clinical research studies.

Purpose: To evaluate whether the CS provides similar results to the PS in PLIF, in terms of fusion rate, clinical and surgical outcomes, and complications.

Study Design: This is a prospective, randomized, noninferiority trial.

Patient Sample: Seventy-nine eligible patients were randomly assigned to either Group A (39 patients), for which PS was used, or Group B (40 patients), for which CS was used.

Outcome Measures: The primary study end point was to measure fusion rate using dynamic radiographs and computed tomography scans. Secondary end points included intensity of low back pain and pain radiating to the leg using visual analog scales, and also, functional status using the Oswestry Disability Index, surgical morbidity, and additional outcomes such as pedicle fracture and mechanical failure.

Methods: We compared baseline data in both groups. To evaluate the efficacy of CS in PLIF compared to PS, we compared fusion rates, clinical outcomes, and complications after surgery in both groups.

Results: At the 6- and 12-month follow-up points, similar fusion rates were observed in both groups (p=.81 and 0.61, respectively). According to the clinical outcome, CS provided similar improvements in pain amelioration and functional status compared to PS, with no significant differences. Additionally, CS resulted in significantly less surgical morbidity, including shorter incision length, quicker operative time, and less blood loss, compared to PS.

Conclusions: CS in PLIF provides similar clinical and radiologic outcomes compared to PS in PLIF. On the basis of the present study, we suggest CS to be a reasonable alternative to PS in PLIF.