Comparison Between 3-DimensionalPrinted Titanium and Polyetheretherketone Cages: 1-Year Outcome After Minimally Invasive Transforaminal Interbody Fusion

Abstract

Objective: Three-dimensional (3D)-printed titanium implants have been developed recently, but the utility is not yet proven. The aim of this study was to compare 3D-printed titanium and polyetheretherketone (PEEK) implants after minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). Methods: Between October 2018 and September 2021, we retrospectively analyzed 83 patients who underwent single-level MIS-TLIF (3D-printed titanium, 40; PEEK, 43). Radiologic parameters were assessed with x-ray and computed tomography (CT) at postoperative 1 week, 6 months, and 1 year. Clinical status was evaluated using Oswestry Disability Index, visual analogue scale score, and Bridwell fusion grading was assessed on 6-month and 1-year postoperative CT. Results: There were no differences between the 2 groups in demographics and clinical outcomes. At 1-year of follow-up, the reported 3D-printed titanium fusion grades were grade I: 77. 5% (31 patients), grade II: 17. 5% (7 patients), and grade III: 5% (2 patients). The PEEK fusion grades were grade I: 51. 2% (22 patients), grade II: 41. 9% (18 patients), and grade III: 7. 0% (3 patients). For overall fusion rate (grade I + II), there was no difference between the 2 cages (95. 0% vs. 93. 0%, p = 0. 705), but grade I was reported at a higher incidence in 3D-printed titanium than PEEK (77. 5% vs. 51. 2%, p = 0. 013). There was no difference between cages based on subsidence and complications. Conclusion: There were no significant differences in the overall fusion rate for MIS-TLIF surgery between 3D-printed titanium and PEEK, but the fusion grade was better in 3Dprinted titanium than in PEEK. Long-term follow-up is required to verify the effectiveness.