Procedure for Reconstruction, Modeling, and Fabrication Using Additive and Rapid Tooling Methods of a Training Model for Transsphenoidal Surgery

The endoscopic transsphenoidal approach (ETA) is a novel approach used by neurosurgeons and otolaryngologists to treat pituitary adenoma, and it has a long learning curve. Training is mostly performed using cadaver heads, but their low availability and cost can limit their use. ETA training models can be used to overcome these limitations. In this panorama, additive manufacturing (AM) technologies represent a more flexible and cost-effective solution to fabricate custom-made training models. Their development involves computed tomography (CT) segmentation, STL file elaboration, direct 3D printing, and rapid parts tooling. This work presents and discusses the entire procedure applied to a modular ETA training model. The procedure starts with selecting the material and AM processes based on a literature review. Accordingly, the parts of the model were designed, 3D printed, or rapid cast. In particular, fused filament fabrication (FFF) was adopted for those tissues whose materials could be directly printed (bones and cartilage), while the rapid casting of silicone was adopted for soft tissues (skin and mucosa) together with FFF to fabricate mold patterns and cores. After fabrication and assembly, the model was finally tested by an experienced neurosurgeon who provided feedback. Moreover, the cost and time of the prototype fabrication were assessed. Results validated the proposed solution from both the surgical and commercial points of view. Moreover, general procedures for designing and rapidly fabricating ETA models were generalized to make them exploitable to more general case studies.