Cortical bone trajectory versus cement-augmented pedicle screws in osteoporotic lumbar surgery: 24-month patient-reported outcomes and recorded complications

PURPOSE: Cement-augmented pedicle screws (CPSCA) and cortical bone trajectory (CBT) screws are used to enhance the fixation strength in osteoporotic bone, but direct comparative clinical evidence remains limited. This study compared 24-month patient-reported outcomes, hospital stay, and complication profiles after CBT versus CPSCA instrumentation in osteoporotic patients undergoing lumbar fixation with interbody fusion. METHODS: This retrospective cohort study included 134 patients with a bone mineral density T-score < - 2.5 who underwent one- to four-level lumbar fixation with interbody fusion between 2015 and 2021 (CPSCA, n = 63; CBT, n = 71). Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) scores were assessed preoperatively and at a standardized 24-month clinical assessment, conducted in outpatient clinics or by structured telephone follow-up. Primary multivariable models adjusted for age and number of fusion levels. Expanded sensitivity models additionally incorporated sex, bone mineral density, baseline outcome severity, surgical year, and radiographic follow-up duration where applicable. Complications, reoperations, and minimal clinically important difference (MCID) responder rates were also compared. RESULTS: At 24 months, CBT was associated with comparative VAS improvement than CPSCA (adjusted β = 13.39% points, p < 0.001), comparative ODI improvement (adjusted β = 8.53% points, p = 0.003), and shorter hospital stay (adjusted β = -3.00 days, p = 0.020). These associations remained statistically significant in expanded sensitivity analyses. All CBT patients met the predefined MCID thresholds for VAS and ODI, compared with 90.5% and 87.3% of CPSCA patients, respectively; the exact 95% confidence interval for each 100% CBT responder rate was 94.9-100.0%. Recorded perioperative complications occurred in 5 of 63 CPSCA patients (7.9%) and 4 of 71 CBT patients (5.6%; p = 0.734), while reoperation rates were 7.9% and 5.6%, respectively (p = 0.734). Cement leakage occurred only after CPSCA, whereas screw loosening occurred only after CBT. No individual complication differed significantly between groups. CONCLUSION: In this retrospective cohort, CBT instrumentation was associated with comparative 24-month improvement in pain and disability and shorter hospitalization than CPSCA after adjustment for measured covariates. Complication and reoperation rates did not differ statistically, although complication patterns varied between techniques. Because treatment allocation was non-randomised, surgeon and instrumentation effects could not be separated, and the study was underpowered for uncommon adverse events, these findings require cautious interpretation and prospective validation.