New, Innovative, Three-Dimensional In Vivo Model for High-Level Microsurgical and Supermicrosurgical Training: A Replacement for Animal Models.

Microsurgery and supermicrosurgery are surgical subdomains necessary for a large variety of surgical disciplines. So far, there is no training model for lymphatic surgery or perforator flap surgery, and the most commonly used microsurgical training models are living animals. However, the ethical principles of replacement, refinement, and reduction (the three Rs) of living animals for training purposes were implemented, highlighting the necessity of an animal-sparing microsurgical training model. Formed during embryogenesis, the chick chorioallantoic membrane resembles a highly vascularized, noninnervated membrane within fertilized chicken eggs. The aim of this study was to utilize the chorioallantoic membrane model as an innovative and versatile training model for supermicrosurgery and microsurgery that can reduce the number of animals used for these purposes. The variety of different sized vessels for the implementation of an anastomosis proved the chorioallantoic membrane model as a well-functioning supermicrosurgical and microsurgical training model. The circulatory system is resilient enough to withstand the mechanical stress applied to the tissue, and the patency of the implemented anastomosis can be tested for the verification of the procedures. In summary, the integration of the chorioallantoic membrane model into a surgical training program can benefit its quality by representing a realistic anatomical and physiological model with a high variety of vascular structures. Moreover, the chorioallantoic membrane model satisfies the principles of replacement, refinement, and reduction as an animal-sparing model, indicating the potential of this model as an innovative microsurgical training model for the improvement of surgical skills.