Factors Affecting the Fusion Process and Comparison of PLIF and TLIF Techniques in Lumbar Interbody Fusion

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To evaluate factors affecting the fusion process and to compare radiological and clinical outcomes among different surgical techniques in patients undergoing posterior lumbar interbody fusion (PLIF). SUMMARY OF BACKGROUND DATA: PLIF is widely performed to restore spinal stability in degenerative lumbar conditions. The rate and timing of solid fusion are influenced by multiple patient- and surgery-related factors, including age, sex, graft type, cage usage, smoking, and diabetes status. Understanding these factors is essential for optimizing surgical planning and postoperative outcomes. METHODS: Seventy-three patients who underwent PLIF for degenerative lumbar pathologies with a minimum of 24 months of follow-up were retrospectively analyzed. Patients were stratified according to age, sex, smoking status, diabetes, graft type, cage usage, and surgical technique (PLIF, PLIF+facetectomy, TLIF). Fusion status was evaluated using the Bridwell fusion criteria. Radiological parameters (lumbar lordosis, sacral inclination, four-to-floor angle, disc height) and clinical outcomes (Odom's criteria) were compared. Statistical analyses were performed using SPSS v27.0; a P value