P12. MODERNIZING GEPPETTO’S WORKSHOP: PREDICTING AESTHETIC OUTCOMES OF 3D-PRINTED, PATIENT-SPECIFIC DORSAL NASAL IMPLANTS UTILIZING A NOVEL IMAGING PROTOCOL

Abstract

PURPOSE: To develop a low-cost, rapid protocol for the design and production of custom-fabricated dorsal nasal implants. METHODS: For protocol validation, we utilized facial CT data to provide “ground truth” patient anatomy. Using these data, 3D models of the subject’s skull and soft tissue were 3D-printed with polylactic acid (PLA) and cast in silicone, respectively. This “face phantom” was imaged to generate a 3D photograph utilizing commercially available photogrammetry software. Desired augmentation was determined via virtual deformation of this model. A corresponding, custom-designed dorsal nasal implant was 3D-printed in PLA, implanted on the phantom, and reimaged as above. To demonstrate fidelity, the photogrammetrically-derived model with and without augmentation was co-registered and compared to CT-derived “ground truth”. RESULTS: Photogrammetric comparison between the 3D photograph and CT-derived “ground truth” revealed an average Hausdorff distance of 0.198 mm (95% 0.640 mm; Dice coefficient=0.989). Dorsal nasal augmentation revealed an average Hausdorff distance of 0.381 mm (95% 1.56 mm; Dice coefficient=0.978) compared to “ground truth.” Comparison between expected and actual augmentation revealed an average Hausdorff distance of 0.276 mm (95% 1.24 mm; Dice coefficient=0.985). Heatmap analysis demonstrated high congruence in all relevant anatomical areas, with variation exclusively noted along the nasal dorsum as expected. CONCLUSION: Our imaging protocol produces a highly accurate means of capturing critical facial anatomy necessary for design of custom-fabricated dorsal nasal implants.