Non-destructive evaluation of patient-specific cranial implants using microcomputed tomography

Abstract

The combination of computer – aided design (CAD) techniques based on computed tomography (CT) data support the planning of patient – specific implants massively. During the last decade, Geometric Morphometric (GMM) methods utilizing thin – plate splines (TPS) were increasingly used to estimate missing data in clinical cases that are characterized by large skull defects featuring partly and completely missing midsagittal planes. Applying a dedicated reconstruction protocol, GMM methods enable the design of personalized cranial implants that accurately reproduce the bone thickness of the affected area. In this study we applied a TPS based reconstruction approach to design a cranial implant of a clinical case that features the bone thickness distribution in the affected region. This virtual model was subsequently additively manufactured (AM) by fused filament fabrication (FFF) using polyetheretherketone (PEEK). The 3D - printed implant was non – destructively investigated via X-ray microcomputed tomography (XCT). The nominal – actual comparison between the designed virtual model and XCT scan of the final implant showed an average deviation in terms of root mean square (RMS) error of 0.168 mm. Additionally, a pore analysis of the 3D printed implant was carried out showing a porosity of 0.07%.