3D printed titanium banana interbody cages versus titanium-coated PEEK bullet cages for TLIF

Introduction: Lumbar degenerative spinal disease is a common, major cause of pain and disability. Titanium and polyetheretherketone (PEEK) are popular materials for interbody implants although evidence is mixed on which material is superior in terms of fusion and subsidence. The purpose of this study was to evaluate the clinical outcome of 3D printed titanium (3DPT) cages in patients undergoing TLIFs, as well as complication profiles based on widely used outcome metrics and reoperation events. Methods: A retrospective review was conducted for patients receiving 1- or 2-level TLIF at an academic medical center between January 2018 and May 2022. Patients were divided into two cohorts according to the material of interbody cage(s), either 3DPT banana or titanium-coated PEEK bullet. Radiographs, patient-reported outcome measures (PROMs), and complications were analyzed and compared. All included patients had radiographic and clinical follow-up of at least one year. Results: 200 patients with 277 interbody cage-implanted levels were included. Patients received either 3DPT (n = 140) or PEEK (n = 60) interbody cages with 202 and 75 instrumented vertebral levels per cohort, respectively. At one year, the 3DPT cohort demonstrated a higher fusion rate of 93.3 % compared to the PEEK cohort's fusion rate of 73.2 % (p < 0.0001). Subsidence rates were 6.0 % and 25.0 % for the 3DPT and PEEK groups, respectively (p < 0.0001). Conclusion: While 3DPT and PEEK interbody cages demonstrated few adverse events at short- and long-term follow-up, 3DPT exhibited a higher rate of fusion and lower rate of subsidence at one year.