Predictors of Cranioplasty Failure: A Retrospective Cohort Study of 302 Patients

BACKGROUND: Cranioplasty is a frequently performed neurosurgical procedure, yet long-term durability remains variable and the factors predicting success or failure are not well established. METHODS: We conducted a review of 302 adult patients who underwent cranioplasty at two tertiary centres between 2014 and 2021. Cranioplasty failure was defined as implant removal due to infection, structural failure or autologous bone resorption. Univariate and multivariate logistic regression analyses were performed to assess associations between failure and clinical variables including cranioplasty material, indication for initial craniectomy, defect site and size and having a prior cranioplasty. RESULTS: The overall cranioplasty failure rate was 11.3%. Autologous bone was used in the majority of reconstructions (66.5%), with the remainder utilising alloplastic materials. Infection rates did not differ significantly between autologous and alloplastic reconstructions. Univariate analysis showed higher failure rates following trauma-related craniectomies. Multivariate regression demonstrated that trauma-related indications were independently associated with increased failure risk (OR 3.06, p = 0.003), while other factors including material type, defect site and prior cranioplasty were not statistically significant. In a separate model, large defects were not significantly associated with failure (OR 0.72, p = 0.50). CONCLUSION: Cranioplasty failure remains a multifactorial complication. Trauma-related indication was independently associated with increased failure risk, while material type, defect site and prior cranioplasty were not significant predictors. These findings highlight the need for prospective studies and longer-term surveillance, particularly in patients undergoing reconstruction following traumatic brain injury.