D103. Automated Carving of Auricular Frameworks in Microtia Reconstruction

PURPOSE: This study assesses the feasibility and efficiency of 3D milling of auricular frameworks. Although manual carving of autologous costal cartilage is the current gold standard for microtia reconstruction, 3D milling of cadaveric costal cartilage for auricular framework production has the potential to improve both efficiency and reproducibility. METHODS: A Nagata/Firmin style auricular framework was manually carved out of soap and scanned using a 3D Shape model scanner. Images were imported, analyzed, and exported into an APSX Spyder Computer Numerical Control (CNC) machine. En bloc frameworks were then milled from human cadaveric cartilage. Time to mill a complete framework was recorded and the completed framework was scanned for dimensional and volumetric analysis. RESULTS: Total milling time for the cartilage framework was approximately 7 minutes. Finalizing logistical steps took 20 minutes. Total time to produce the completed framework was approximately 27 minutes, compared to the traditional 1-2 hours by manual carving. The milled framework dimensions were all within 2 mm of the manual model dimensions. Volumetric analysis of the milled and manual frameworks showed 71% similarity. CONCLUSION: En bloc cadaveric costal cartilage framework milling is feasible and efficient. 3D milling significantly reduces framework production time and allows for reproducibility of the complex ear geometry. Use of cadaveric costal cartilage allows for pre-operative auricular framework production, eliminating an additional procedure for autologous rib harvesting. Faster framework production and reduced time in the operating room can translate to significant cost savings. The next step toward achieving clinical application is ensuring reliable framework sterility.