3D-printed temporal bone models for training: Does material transparency matter?

To investigate the impact of 3D-printed temporal bone models with two different material transparencies on trainees' mastoidectomy performance. Eleven ORL residents performed two anatomical mastoidectomies with posterior tympanotomy on two 3D-printed models with different transparency and VR simulation training. Participants where divided into two groups based on their experience. Within each group participants were randomized to start with the model printed in a completely opaque material or in a material featuring some degree of transparency. After drilling on 3D-printed models, the participants performed two similar mastoidectomies on human cadavers: one on the left side of one cadaver and one on the right side of another cadaver. After drilling 3D-printed models and cadavers, the final-product performances were evaluated by two experienced raters using the 26-item modified Welling Scale. Participants also evaluated the models using a questionnaire. Overall, the participants performed 25 % better on the 3D-printed models featuring transparency compared to the opaque models (18.6 points vs 14.9 points, mean difference = 3.7, 95 % CI 2.0-5.3, P