Gibreel, Waleed

Although complications of autologous bone flap cranioplasty are well described, data on long-term bone flap survival and the comorbidities associated with secondary reconstruction are limited. This study aimed to quantify the need for secondary alloplastic cranioplasty within a standardized patient cohort. Patients who underwent delayed cranioplasty following craniectomy with banked, frozen autologous bone between 2012 and 2025 were identified and analyzed using Cox regression, spline analysis, and Kaplan–Meier survival analysis. A total of 367 patients with an average age of 39.2±19.7 years (range: 0.3–84.4 years) at the time of cranioplasty were included. A secondary cranioplasty was required in 13.6% of patients (n=50 of 367), with resorption (52%) and infection (42%) as the most common indications. In adjusted analyses, patients who underwent cranioplasty following a traumatic injury (HR: 2.37; 95% CI: 1.07–5.26; P =0.03) and patients younger than 18 years (HR: 2.99; 95% CI: 1.35–6.62; P =0.01) were more likely to require a secondary cranioplasty due to bone flap resorption. Increasing defect size was also associated with a higher risk of secondary cranioplasty due to bone flap resorption, becoming significant at roughly 95 cm² (HR: 2.54; 95% CI: 1.04–6.20; P =0.04). The estimated cumulative incidence of secondary cranioplasty was 37% at ten years after autologous reconstruction. These results indicate that although autologous bone flap cranioplasty is largely effective, select patients face a substantially higher risk of secondary cranioplasty, and alternative reconstructive options may be warranted.