STA-MCA bypass using ex vivo and synthetic hybrid model

Introduction: Execution of cerebrovascular bypass requires the development of specific high complexity technical skills. The logic for creating vascular anastomosis training models is that this procedure is considered the most challenging in neurosurgery. Vascular bypass simulation models traditionally involve dead animals, e.g., chicken wing, livestock or synthetic templates.

Objective: Provide a microsurgical hybrid model for practice and improvement of the techniques reacquired for the Superficial Temporal Artery–Middle Cerebral Artery bypass using a 3D printed synthetic skull associated with human placentas. Methods Signed informed consent was obtained from pregnant women and screening prenatal infection was performed. After washing the placenta in running water, saline was injected into the vein and the two umbilical arteries to remove any clots within blood vessels. The allantoic membrane was removed to allow a better visualization of the vessels. The two arteries of the placenta were cannulated. After this preparation, one placenta was inserted into the skull, before placing itself the target vessel (simulated MCA) in the craniotomy area and the other positioned outside the skull (simulated STA). We invited 6 neurosurgeons with experience in microsurgery vascular (group Expert) and 6 residents in neurosurgery of the 3rd and 4th year (group Beginners) for the validation of the exercises. All were asked to perform a simulation of an end-to-side anastomosis (ATS-ACM).

Results: The similarities of microsurgical tasks for the ATS-ACM bypass surgical were evaluated. According to the opinion of experts and novices, the suggest model was not similar to all surgery, but the microsurgery tasks were very similar. The use of microsurgical instruments, microscope and the microsurgical handling of vessels were exactly as in real surgery. Microsurgical dissection of tissues was classified as very similar. The time required for complete the assignment was statistically different in the two groups. The novice group without any previous experience microsurgical had difficulty on all tasks.

Conclusion: Our results show the possibility to realize all main tasks and steps of the surgical procedure in question. It favors the pedagogical principle of progressive learning. The exercise may be well completed only after the proper execution of all tasks. The hybrid model proposed offer one singular training tool for ATS-ACM bypass surgeries, showing high fidelity and low cost.