Comparison of Cortical Bone Trajectory and Percutaneous Pedicle Screw Fixation in PETLIF: Short-Term Perioperative Muscle Injury and Pain Outcomes

Background/Objectives: Full-endoscopic transforaminal approach lumbar interbody fusion using the percutaneous endoscopic transforaminal lumbar interbody fusion (PETLIF) system is increasingly adopted as a minimally invasive technique for degenerative lumbar disorders. Screw trajectory selection may influence tissue handling, muscle injury, and postoperative pain. Comparative evidence between percutaneous pedicle screws (PPS) and cortical bone trajectory (CBT) screws in PETLIF is limited. This retrospective, non-randomized comparative study evaluated short-term outcomes between CBT and PPS fixation, focusing on muscle injury and early postoperative pain. Methods: This retrospective study included 140 patients who underwent single-level PETLIF between July 2021 and June 2025 (PPS: 69; CBT: 71). Allocation to PPS or CBT fixation was based on surgeon preference. Operative time, blood loss, hemoglobin (Hb) and creatine kinase (CK) levels, slip correction, Japanese Orthopaedic Association (JOA) scores, and visual analog scale (VAS) scores for low back pain were evaluated. Direct decompression was performed more frequently in the CBT group. Laboratory data were collected preoperatively and on postoperative days 1, 3, and 7. Results: Blood loss was higher in the CBT group due to more frequent decompression, although postoperative Hb changes were similar. CK elevation on postoperative day (POD) 1 was associated with lower values in the CBT group (753.0 ± 276.7 U/L vs. 539.3 ± 322.4 U/L). Slip correction and JOA improvement were comparable. Early postoperative low back pain (POD 7) was significantly lower in the CBT group (3.2 ± 2.2 vs. 2.3 ± 1.9). Conclusions: CBT fixation in PETLIF was associated with lower short-term muscle injury and early postoperative pain while maintaining radiological and functional outcomes comparable to PPS. However, the higher frequency of direct decompression in the CBT group represents an important potential confounder. This study evaluated only ultra-short-term perioperative outcomes up to 60 days; long-term endpoints such as fusion rate, cage subsidence, screw loosening, and adjacent segment disease were not assessed.