Application of Computer-Assisted Design and Manufacture in Unilateral Alloplastic Microtia Reconstruction, H Chen, ZC Chen.

Date: September 17, 2015.
Source: 16th Congress of International Society of Craniofacial Surgery (ISCFS) 2015.
Presenter: Hsin-Yu Chen.
Background: The advances in 3D scanning, computer-assisted design and manufacture (CAD/CAM), and rapid-prototyping technology make customizing a symmetric auricular framework feasible for unilateral microtia patients. In this study, we used an active stereo-photogrammetry system to acquire the 3D geometric data of patient’s normal ear for template design and presented our algorithm of producing a customized template using CAD/CAM technology.
Methods: Three dimensional photographs of the patient’s head were captured using the 3dMDcranial System. Eight sets of 3D geometric surface images were obtained for each patient. The resulting 3D surface images were visualized on 3dMDvultus software, in which we selected the 3D images displaying the most detailed structures of the normal ear. The normal ear segment was converted into a virtual solid as the basis for framework construction. Geomagic Freeform software and Touch X Haptic device were used for virtual sculpture of the template. The definitions of the virtual template were tailored to each patient’s unique auricular morphology. The final 3D model was mirrored to the defect side and the template was printed out of biocompatible acrylic.
Results: Five patients with unilateral microtia were enrolled in the study with mean age of 11 years old. Three patients had hemifacial microsomia on the same side. Single stage total ear reconstructions were performed. The customized template served as a guide for positioning and sculpture of Medpor framework. In addition, the templates were used to simulate the appearance after skin draping and helped the surgeon to determine the appropriateness of soft tissue coverage. Four patients received single stage total auricular reconstruction with Medpor. One patient received stage procedure with insertion of Medpor framework without projection because the temperoparietal fascia was insufficient to cover the entire implant.
Conclusion: The 3dMD stereo-photogrammetry is reliable in acquiring the 3D model of the normal ear. The customized 3D template can be obtained with the assistance of the 3dMD stereo-photogrammetry system for accurate 3D model acquisition and the CAD/CAM technology for precise and symmetric design.

Article: Application of Computer-Assisted Design and Manufacture in Unilateral Alloplastic Microtia Reconstruction.
Authors: H Chen, ZC Chen, Craniofacial Research Center, Division of Craniofacial Surgery, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung Medical College and University, Taiwan.

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