Autologous ear reconstruction: Towards a semiautomatic cadbased procedure for 3D printable surgical guides

The autologous ear reconstruction surgery, i.e. the reconstruction of the missing ear anatomy with autologous cartilage tissue in case of partial or complete absence of the auricular region, can be extremely complicated due to the unique shape and size of this anatomical region. Operations of sculpting and carving of the costal cartilage in order to realize the ear reproduction require a high degree of manual expertise and experience from the surgeon. The development of surgical aids that can provide the physician with guidelines during the reconstruction is being studied in the literature. However, state-of-the-art techniques do not represent the optimal solution and only partially help in the reconstruction process. They are based on two-or three-dimensional templates of the target anatomy, providing visual support, yet not helping in the actual reconstruction phase, or, in some cases, by providing active aid but not simplifying the procedure sufficiently. In this context, the option of creating custom cutting guides that could actively assist the surgeon both in the pre-operative planning phase and during the surgery was considered. The proposed approach involves the use of surgical guides adopted for the cutting and reconstruction of the individual anatomical elements involved. Through an iterative process carried out in collaboration with the surgeon the characteristics of the surgical guides have been defined. Subsequently, a method that can be applied systematically to model the cutting guides, ready to be printed with additive production techniques was defined. The procedure was designed with a view to a future semi-automatization of the entire process that could make the physician autonomous in the realization of the patient-specific guides.