title: Evolution of design considerations in complex craniofacial reconstruction using patient-specific implants.
abstract: Previously published evidence has established major clinical benefits from using computer-aided design, computer-aided manufacturing, and additive manufacturing to produce patient-specific devices. These include cutting guides, drilling guides, positioning guides, and implants. However, custom devices produced using these methods are still not in routine use, particularly by the UK National Health Service. Oft-cited reasons for this slow uptake include the following: a higher up-front cost than conventionally fabricated devices, material-choice uncertainty, and a lack of long-term follow-up due to their relatively recent introduction. This article identifies a further gap in current knowledge - that of design rules, or key specification considerations for complex computer-aided design/computer-aided manufacturing/additive manufacturing devices. This research begins to address the gap by combining a detailed review of the literature with first-hand experience of interdisciplinary collaboration on five craniofacial patient case studies. In each patient case, bony lesions in the orbito-temporal region were segmented, excised, and reconstructed in the virtual environment. Three cases translated these digital plans into theatre via polymer surgical guides. Four cases utilised additive manufacturing to fabricate titanium implants. One implant was machined from polyether ether ketone. From the literature, articles with relevant abstracts were analysed to extract design considerations. In all, 19 frequently recurring design considerations were extracted from previous publications. Nine new design considerations were extracted from the case studies - on the basis of subjective clinical evaluation. These were synthesised to produce a design considerations framework to assist clinicians with prescribing and design engineers with modelling. Promising avenues for further research are proposed.
authors.affiliation: 1 PDR - International Centre for Design & Research, Cardiff Metropolitan University, Cardiff, UK.
authors.forename: Sean
authors.initials: S
authors.lastname: Peel
authors.affiliation: 2 University Hospital of Wales, Cardiff & Vale University Health Board, Cardiff, UK.
authors.forename: Satyajeet
authors.initials: S
authors.lastname: Bhatia
authors.affiliation: 1 PDR - International Centre for Design & Research, Cardiff Metropolitan University, Cardiff, UK.
authors.forename: Dominic
authors.initials: D
authors.lastname: Eggbeer
authors.affiliation: 2 University Hospital of Wales, Cardiff & Vale University Health Board, Cardiff, UK.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Morris
authors.affiliation: 2 University Hospital of Wales, Cardiff & Vale University Health Board, Cardiff, UK.
authors.forename: Caroline
authors.initials: C
authors.lastname: Hayhurst
mesh_terms: D017076:Computer-Aided Design; D005147:Facial Bones / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D066330:Printing, Three-Dimensional; D011474:Prosthesis Design / Q000379:methods*; D012886:Skull / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed
keywords: Implants/prosthetics; additive manufacturing; computer-aided design; computer-assisted surgery; orthopaedic materials; surgical guides; three-dimensional printing