Quantitative analysis of osseointegration of glass fiber-reinforced composite-bioactive glass cranial implants

BACKGROUND: Glass fiber-reinforced composite-bioactive glass (FRC-BG) implants are emerging as an alternative to autologous bone grafts with the potential for new bone formation and ingrowth from the surrounding skull. However, clinical evidence of osseointegration remains to be demonstrated. OBJECTIVE: To evaluate radiological measures of osseointegration of FRC-BG implants used for cranioplasty. METHODS: A retrospective cohort study was conducted including adult patients who underwent cranioplasty with FRC-BG implants between 2016 and 2021. Sequential non-contrast head CT-scans were obtained within 24 h postoperatively and after one year of follow-up. Using three-dimensional (3D) segmentation and analysis software, changes in bone volume (in cm3) and bone density (in Hounsfield units [HU]) of a standardized one cm-wide region of skull bone surrounding the margins of the FRC-BG implants were quantified. Paired samples t-tests assessed differences between baseline and after one year of follow-up. RESULTS: A total of 38 patients were included (mean age 50.2 ± 18.4 years). After one year of follow-up, significant increases were observed in both skull bone volume (mean difference 6.04 cm3, 95% confidence interval [CI] 4.65-7.43, p < 0.001) and skull bone density (mean difference 45.84 HU, 95% CI 1.15-90.52, p = 0.045) surrounding the FRC-BG implants. CONCLUSION: The present study shows radiological signs of osseointegration of FRC-BG implants used for cranioplasty.