Researchers conducted a retrospective study of data obtained prospectively. For a study, they sought to determine if posterior lumbar interbody fusion (PLIF) with cortical bone trajectory screw fixation (CBT-PLIF) was inferior to PLIF with traditional trajectory screw fixation (TT-PLIF) in terms of early fusion status and if the titanium-coated polyetheretherketone (PEEK) cage (TP cage) improves early fusion status when compared to a pure PEEK cage (P cage) of the same shape. The subjects included 37 patients who underwent TT-PLIF with P cages (TT-P group), 24 patients who underwent CBT-PLIF with P cages (CBT-P group), 32 patients who had TT-PLIF with TP cages (TT-TP group), and 20 patients who underwent CBT-PLIF with TP cages (CBT-TP group). Cyst signals were assessed and classified as diffuse or local cysts on multiplanar reconstruction computed tomography 6 months following surgery. 1 year after surgery, both dynamic plain radiographs and multiplanar reconstruction computed tomography were used to determine early fusion status. The diffuse cyst was found in 27.0% of the TT-P group, 29.2% of the CBT-P group, 25.0% of the TT-TP group, and 25.0% of the CBT-TP group (P>0.05). The TT-P group had a 75.7% early fusion rate; the CBT-P group had a 75.0% early fusion rate, the TT-TP group had a 71.9% early fusion rate, and the CBT-TP group had a 75.0% early fusion rate (P>0.05). The outcomes show that CBT-PLIF produced the same early fusion status as TT-PLIF and that the TP cage did not improve early fusion status following both TT-PLIF and CBT-PLIF when compared to the exact shape P cage.