Due to a limited availability of human bone for training purposes in ear surgery, authentic models are needed. The Magdeburg temporal bone model (Mtbm) is an epoxy resin facsimile of a human os temporale which is manufactured by 3D printing based on human computed tomography data. Here, the processing properties of the Mtbm are investigated with respect to the drilling and milling behavior and the elastic modulus. Results are compared with those of human os temporale. The forces during drilling and milling and the elastic moduli show significant differences between both types of materialall values are significantly higher for bone. However, reproducing the trabecular structure of human bone results in a similar degree of force fluctuations. Thus, an authentic feeling for the surgeon is roughly provided by the AFM.

Cochlear implant surgery on highly hearing impaired and deaf patients presents surgeons with major medical challenges. In advance of the operation, the surgeon must gain the necessary dexterity and topographical knowledge in the field of microsurgery. For these purposes human cadaver specimens are usually used but they are not sufficiently available. Therefore, our group from the University of Magdeburg researches and develops a manufacturing process for producing individual anatomical facsimile models (AFM) of the human ear bone, which originally simulate the cavity structure of the inner ear (cochlea, semicircular canals) by using rapid prototyping methods. For this production a variety of biomechanical data of the human ear bone are needed to recreate the later models with the same biomechanical properties. By using these obtained biomechanical data and the individual patient's CT data, stereolithography models of UV-sensitive epoxy resin can be produced. The models can be emulated to the biomechanical properties of the human bone by varying the curing process of the epoxy resin. Thus, the authentic drilling and milling properties give the surgeon the possibility to develop the skills needed in dealing with microsurgical instruments. At the same time the authenticity of the AFM promotes the study of the anatomical structure and the orientation of anatomical landmarks.

The quality of T cell responses differs dramatically during infancy and has been implicated in the susceptibility to infections, but the underlying cellular pathways are not well known. Here, we determined the effector phenotype of T cells in adenoids of 103 children with adenoid hypertrophy that underwent adenoidectomy. We compared children with sole upper airway obstruction with those suffering from concomitant otitis media with effusion or recurrent infections of the upper airways. Multifunctionality of T cells was determined as co-production of IFNγ, IL2, IL17 and TNFα using flow cytometry. Boolean gating was performed in FlowJo and analyzed using SPICE software. Statistical analysis was done by one-way-ANOVA.We found that CD4 and CD8 T cells of all disease groups and at any examined age were able to co-produce all possible cytokine combinations. For CD8 T cells, patients exclusively showing upper airway obstruction accumulated 28% more triple and 30% more double producers compared with those suffering from subsequent infectious symptoms, while the latter had 15% more single producers. CD4 T cells showed similar results.Analyzing the age-dependent changes in T-cell-quality, for CD4 T cells it can be stated that children of one and two years of age had 30% more double and 16% less single producers than older children, implying that multifunctionality increases with age. Additionally, for CD8 T cells children of at least three years had 47% more triple producers than two-year-olds. Children ≥3 years further had 38% more triple and 36% more double producers compared to younger children and 18% less single producers, suggesting a clear increase of cytokine co-expression between two and three years of age.In conclusion, a correlation of multifunctional T cells with clinical symptoms can be established. Our data also show that two to three years of age are a critical period in an infant´s life to develop a higher quality of T cell responses.