A Retrospective Comparative Study to Evaluate the Clinical Efficacy Using a Bioactive Glass Ceramic Spacer in Posterior Lumbar Interbody Fusion

Considering the advancement of bone graft substitution, the authors aimed to achieve clinical safety by simultaneously using one bioactive ceramic spacer (NovoMax) and a conventional polyetheretherketone (PEEK) cage at first use. We compared the results between different cages, even in the same disc space and to the control group using only conventional PEEK cages. Methods This retrospective analysis included data from patients who underwent posterior lumbar interbody fusion surgery between 2015 and 2017. The hybrid group (H group) included 19 patients with 21 lumbar disc levels, and the control group was defined as the PEEK group (P group), which included 16 patients with 18 disc levels. The degree of fusion was confirmed on computed tomography based on the fusion grade system and dynamic X-rays. We analyzed the fusion rate between the two groups using Cox proportional hazard model. Results There were 14 cases (72.2%) in Group P and 15 cases (71.4%) in Group H with confirmed complete union during the observation period (p=0.62). The relative hazard of incomplete fusion with osteolysis in both the P and H groups was increased by 5.41 times (p=0.004, confidence interval 1.704–17.204). In the H group, significant instrument-related complications, such as fragmentation, slippage, subsidence, and osteolysis were observed in the Novomax cage. Conclusions Using NovoMax could result in osteolysis, cage migration, fragmentation, or subsidence. The use of NovoMax is expected to be compatible for bone fusion surgery, but close attention should be paid to some problems that may accompany it.