Fine versus Sclerotic Trabecular Bone Remodeling/Restructure: A Refined Radiographic Predictor for Long-Term Segment Stability After Posterior Lumbar Interbody Fusion

Study Design Retrospective cohort study. Objectives Successful bone fusion is crucial for favorable posterior lumbar interbody fusion (PLIF) outcomes. While trabecular bone remodeling (TBR) indicates osseointegration, its interpretation remains uncertain. This study aimed to clarify the clinical significance of distinct TBR types—fine TBR (fTBR) and sclerotic TBR (sTBR)—as seen on computed tomography (CT) scans and to evaluate their predictive value for segment stabilization and complete bone fusion and their relationship with interbody cage materials. Methods Seventy-one patients who underwent one-level PLIF with follow-up exceeding 5 years were included. Interbody cages were made of carbon fiber-reinforced polymer (CFRP; 37 segments) or titanium-coated polyether-ether-ketone (TiPEEK; 34 segments). CT images were obtained at 3 months, 1 year, and incidentally at 5 years or later. TBR was classified morphologically as fTBR or sTBR. Results At 1-year postoperatively, the fTBR positivity rate was significantly higher in the TiPEEK group than in the CFRP group (48.6% vs 73.5%, P = .032). The 33 fTBR-positive segments at 3 months had a significantly higher complete fusion rate than 38 fTBR-negative segments (97.0% vs 57.9%, P < .001). There was no significant difference in fusion rates between 27 sTBR-positive segments at 3 months and 44 sTBR-negative segments (66.7% vs 81.8%, P = .15). Conclusions fTBR may serve as a positive indicator for predicting future segment stabilization and bone fusion post-PLIF. sTBR, however, is not associated with future segment stability. This refined TBR classification could enhance postoperative assessment and broaden our understanding of implant-bone integration in spinal fusion.