Patient-Specific 3D Models for Autogenous Ear Reconstruction. KS Khouri; HA Liss; JM Bekisz; PG Coelho; RL Flores; L Witek.

Date: September 2017.
Source: Plastic and Reconstructive Surgery. 5(9S):174–175, DOI: 10.1097/01.GOX.0000526416.08852.96.
Introduction: Autogenous ear reconstruction remains one of the most technically challenging procedures in plastic surgery. Current standards of practice entail tracing the unaffected contralateral ear and using this two-dimensional outline as a surgical model. We present the effectiveness and feasibility of sterilizable, patient-specific and departmentally produced 3D-printed constructs as intraoperative models for autogenous ear reconstruction.
Methods: 3D photographs (3DMD, Atlanta, GA) of the unaffected ears of three patients with unilateral microtia are taken and uploaded into Amira (FEI Company, Hillsboro, Oregon, USA), where they are transformed to (.stl) digital models. These models are rendered and imported into Blender™ (Amsterdam, The Netherlands). They are then inverted along the vertical axis to create a working template of the contralateral ear. The depths of the scapha, triangular fossa and cymba are deepened to accentuate contours. Additional relief is added to the helical root for further definition. The final template is digitally separated to create the requisite components for the Nagata technique: helix; antihelical fold with the superior and inferior crus; tragus; and base frame. The helix is digitally straightened to optimize modeling. Finally, the complete auricular model and its components are individually 3D-printed (Builder Premium 3D Printer, Noordwijkerhout, The Netherlands) using polylactic-acid filament and sterilized according to manufacture’s specifications (121°C for 1 hour and 30 minute dry cycle).
Results: Average time of digital preparation and 3D-printing was 5 and 5.5 hours, respectively. Total cost of consumables was $1.00/construct. On the day of surgery, the sterilized, patient-specific 3D models were brought to the operating room and placed alongside the sculpting tools and carving block. The models were placed on the cartilage grafts so that the forms and relief of the cartilage construct can be easily appreciated and incorporated into the cartilage shape. All three reconstructions were completed without complication and with a high patient satisfaction. Compared to the classic auricular tracings also present during surgery, the 3D printed models provided more detailed anatomic information and eliminated much of the guesswork involved in 3-dimensional auricular reconstruction.
Conclusions: By leveraging software platforms, hardware and expertise already available within academic medical centers, sterilizable, patient-specific auricular 3D models can be affordably manufactured and used during autogenous ear reconstruction.

Article: Patient-Specific 3D Models for Autogenous Ear Reconstruction.
Authors: Kimberly S. Khouri; Hannah A. Liss; Jonathan M Bekisz; Paulo G. Coelho; Roberto L. Flores; Lukasz Witek.