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Frugal 3D scanning using smartphones provides an accessible framework for capturing the external ear

      Summary

      Three-dimensional (3D) scanning technologies, such as medical imaging and surface scanning, have important applications for capturing patient anatomy to create personalised prosthetics. Digital approaches for capturing anatomical detail as opposed to traditional, invasive impression techniques significantly reduces turnaround times and lower production costs while still maintaining the high aesthetic quality of the end product. While previous case studies utilise expensive 3D scanning and modelling frameworks, their clinical translation is limited due to high equipment costs. In this study, we develop and validate a low-cost framework for clinical 3D scanning of the external ear using photogrammetry and a smartphone camera. We recruited five novice operators who watched an instructional video before scanning 20 healthy adult participant ears who did not have microtia.
      Our results show that the smartphone-based photogrammetry methodology produces 3D scans of the external ear that were accurate to (1.5 ± 0.4) mm and were (71 ± 14) % complete compared with those from a gold standard reference scanner, with no significant difference observed between operators. A moderate to strong interrater reliability was determined for all novice operators, suggesting that all novice operators were able to capture repeatable scans. The development of this smartphone photogrammetry approach has the potential to provide a non-invasive, inexpensive and accessible means to capture patient morphology for use in clinical assessment and personalised device manufacture, specifically for ear prostheses. We also demonstrate that inexperienced operators can rapidly learn and apply smartphone photogrammetry for accurate and reliable scans of the external ear with important applications for future clinical translation.

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      References

        • Luquetti D.
        • Leoncini E.
        • Mastroiacovo P.
        Microtia-anotia: A global review of prevalence rates.
        Birth Defects Res Part A. 2011; 91: 813-822
        • Johns A.
        • Lewin S.
        • Im D.
        Teasing in younger and older children with microtia before and after ear reconstruction.
        J Plast Surg Hand Surg. 2016; 51: 205-209
        • Steffen A.
        • Wollenberg B.
        • Konig I.
        • Frenzel H.
        A prospective evaluation of psychosocial outcomes following ear reconstruction with rib cartilage in microtia.
        J Plast Reconstr Aesthet Surg. 2010; 63: 1466-1473
        • Mohammed M.I.
        • Cadd B.
        • Peart G.
        • Gibson I.
        Augmented patient-specific facial prosthesis production using medical imaging modelling and 3D printing technologies for improved patient outcomes: Virtual and Physical Prototyping: Vol 13, No 3.
        Virtual Phys Prototyp. 2018 Jan 18; 13: 164-176
        • Bos E.J.
        • Scholten T.
        • Song W.
        • Verlinden J.C.
        • Wolff J.
        • Forouzanfar T.
        • et al.
        Developing a parametric ear model for auricular reconstruction: A new step towards patient-specific implants.
        J Cranio-Maxillofac Surg. 2015 Apr 1; 43: 390-395
        • Unkovskiy A.
        • Brom J.
        • Huettig F.
        • Keutel C.
        Auricular Prostheses Produced by Means of Conventional and Digital Workflows: A Clinical Report on Esthetic Outcomes.
        Int J Prosthodont. 2018; 31: 63-66
        • He Y.
        • Xue G.
        • Fu J.
        Fabrication of low cost soft tissue prostheses with the desktop 3D printer.
        Sci Rep. 2014 Nov 27; 4: 1-7
        • Yi-jiao Z.
        • Yu-xue X.
        • Wang Y.
        Three-Dimensional Accuracy of Facial Scan for Facial Deformities in Clinics: A New Evaluation Method for Facial Scanner Accuracy.
        PLoS One San Franc. Jan 2017; 12e0169402
        • Ma L.
        • Xu T.
        • Lin J.
        Validation of a three-dimensional facial scanning system based on structured light techniques.
        Comput Methods Programs Biomed. 2009 Jun 1; 94: 290-298
        • Lubbers H.-T.
        • Medinger L.
        • Kruse A.
        • Gratz L.W.
        • Matthews F.
        Precision and Accuracy of the 3dMD Photogrammetric System in Craniomaxillofacial Application.
        J Craniofac Surg. May 2010; 21: 763-767
        • Knoops P.G.M.
        • Beaumont C.A.A.
        • Borghi A.
        • Rodriguez-Florez N.
        • Breakey R.W.F.
        • Rodgers W.
        • et al.
        Comparison of three-dimensional scanner systems for craniomaxillofacial imaging.
        J Plast Reconstr Aesthet Surg. 2017 Apr 1; 70: 441-449
        • Ross M.T.
        • Cruz R.
        • Brooks-Richards T.L.
        • Hafner L.M.
        • Powell S.K.
        • Woodruff M.A.
        Comparison of three-dimensional surface scanning techniques for capturing the external ear.
        Virtual Phys Prototyp. 2018 Oct 2; 13: 255-265
        • Chougule V.N.
        • Gosavi H.
        • Dharwadkar M.
        • Gaind A.
        Review of Different 3D Scanners and Scanning Techniques.
        J Eng. 2018; : 41-44
      1. Artec Space Spider [Internet]. Artec3D. [cited 2020 Aug 17]. Available from: https://www.artec3d.com/portable-3d-scanners/artec-spider-v2.

        • Nightingale R.C.
        • Ross M.T.
        • Allenby M.C.
        • Woodruff M.A.
        • Powell S.K.
        A method for economical smartphone-based clinical 3D facial scanning.
        J Prosthodont. 2020; (Accepted)
        • Koutsoudis A.
        • Vidmar B.
        • Ioannakis G.
        • Arnaoutoglou F.
        • Pavlidis G.
        • Chamzas C.
        Multi-image 3D reconstruction data evaluation.
        J Cult Herit. 2014 Jan 1; 15: 73-79
        • Chit A.u.n.g.S.
        • CK N.g.i.m.R.
        • Lee S T.
        Evaluation of the laser scanner as a surface measuring tool and its accuracy compared with direct facial anthropometric measurements.
        Br J Plast Surg. 1995 Jan 1; 48: 551-558
        • Subburaj K.
        • Nair C.
        • Rajesh S.
        • Meshram S.M.
        • Ravi B.
        Rapid development of auricular prosthesis using CAD and rapid prototyping technologies.
        Int J Oral Maxillofac Surg. 2007 Oct 1; 36: 938-943
        • Ciocca L.
        • Mingucci R.
        • Gassino G.
        • Scotti R.
        CAD/CAM ear model and virtual construction of the mold.
        J Prosthet Dent. 2007 Nov 1; 98: 339-343
        • Liacouras P.
        • Garnes J.
        • Roman N.
        • Petrich A.
        • Grant G.T.
        Designing and manufacturing an auricular prosthesis using computed tomography, 3-dimensional photographic imaging, and additive manufacturing: A clinical report.
        J Prosthet Dent. 2011 Feb 1; 105: 78-82
      2. Verbal communication with prosthetisists.

        • Farook T.H.
        • Jamayet N.B.
        • Abdullah J.Y.
        • Asif J.A.
        • Rajion Z.A.
        • Alam M.K.
        Designing 3D prosthetic templates for maxillofacial defect rehabilitation: A comparative analysis of different virtual workflows.
        Comput Biol Med. 2020 Mar 1; 118103646
        • Charani E.
        • Castro-Sánchez E.
        • Moore L.S.
        • Holmes A.
        Do smartphone applications in healthcare require a governance and legal framework? It depends on the application!.
        BMC Med. 2014 Feb 14; 12: 29
        • Silva B.M.
        • Rodrigues J.J.
        • Canelo F.
        • Lopes I.C.
        • Zhou L.
        A Data Encryption Solution for Mobile Health Apps in Cooperation Environments.
        J Med Internet Res. 2013; 15: e66
        • Goddard M.
        The EU General Data Protection Regulation (GDPR): European Regulation that has a Global Impact.
        Int J Mark Res. 2017 Nov 1; 59: 703-705
        • Abbott L.M.
        • Magnusson R.S.
        • Gibbs E.
        • Smith S.D.
        Smartphone use in dermatology for clinical photography and consultation: Current practice and the law.
        Australas J Dermatol. 2018; 59: 101-107