Clinical and radiological outcomes of non-window-type bioactive glass–ceramic cage in single-level ACDF versus PEEK cage filled with autologous bone

Abstract

Bioactive glass–ceramic (BGC) cage is a substitute for polyether ether ketone (PEEK) cages in anterior cervical discectomy and fusion (ACDF). Only a few comparative studies exist using PEEK and non-window-type BGC cages (CaO–SiO2–P2O5–B2O3) in single-level ACDF. This study compared PEEK cages filled with autologous iliac bone grafts and BGC cages regarding clinical safety and effectiveness. A retrospective case series was performed on 40 patients who underwent single-level ACDF between October 2020 and July 2021 by a single orthopedic spine surgeon. The spacers used in each ACDF were a PEEK cage with a void filled with an autologous iliac bone graft and a non-window-type BGC cage in 20 cases. The grafts were compared pre-operatively and post-operatively at 6 weeks and 3, 6, and 12 months. Post-operative complications were investigated in each group. Clinical outcome was measured, including Visual Analog Scale (VAS) scores of neck and arm pains, Japanese Orthopedic Association score (JOA), and Neck Disability Index (NDI). Dynamic lateral radiographs were used to assess the inter-spinous motion (ISM) between the fusion segment and subsidence. The fusion status was evaluated using a computed tomography (CT) scan. Overall, 39 patients (19 and 20 patients in the PEEK and BGC groups, respectively) were recruited. Eighteen (94.7%) and 19 (95.0%) patients in the PEEK and BGC groups, respectively, were fused 12 months post-operatively, as assessed by ISM in dynamic lateral radiograph and bone bridging formation proven in CT scan. The PEEK and BGC groups showed substantial improvement in neck and arm VAS, JOA, and NDI scores. No substantial difference was found in clinical and radiological outcomes between the PEEK and BGC groups. However, the operation time was considerably shorter in the BGC group than in the PEEK group. In conclusion, a non-window-type BCG cage is a feasible substitute for a PEEK cage with an autologous iliac bone graft in single-level ACDF.