Auricular reconstruction: 3D outcome assessment using photogrammetry

Objective. To develop a smartphone-based three-dimensional photogrammetry protocol for objective quantitative assessment of postoperative symmetry between the reconstructed and contralateral healthy auricle. Material and methods. Thirty-one patients who underwent unilateral auricular reconstruction with autologous costal cartilage were prospectively enrolled. Photography was performed using standard 12-megapixel smartphone camera without calibration targets or specialized equipment. Textured 3D models were generated using 3DF Zephyr software. Four bilateral parameters were measured: ear and width, auriculocephalic angle, and vertical position relative to lateral canthus. Statistical analysis included mean absolute differences, intraclass correlation coefficients (ICC) with 95% confidence intervals, and paired t-tests (p<0.05). Results. High-detail 3D models were successfully generated in all 31 cases. On the average, 46.2±2.1 out of 50 photographs were oriented per session (92.4%). Mean absolute bilateral differences were: ear length 0.61 mm, ear width 0.47 mm, auriculocephalic angle 1.51◦, vertical position 1.02 mm. ICCs exceeded 0.91 for all parameters (length: ICC=0.97; width: ICC=0.96; angle: ICC=0.93; vertical position: ICC=0.91). Conclusion. Smartphone-based 3D photogrammetry with 3DF Zephyr is a non-invasive, accessible, and reproducible tool for objective assessment after auricular reconstruction. High measurement accuracy and minimal equipment requirements support its adoption as a standardized quality-control approach in clinical practice and routine postoperative monitoring of patients with microtia.