Augmented reality and physical hybrid model simulation for preoperative planning of metopic craniosynostosis surgery
Authors: Coelho Giselle , Rabelo Nicollas Nunes , Vieira Eduardo , Mendes Kid , Zagatto Gustavo , Santos de Oliveira Ricardo , Raposo-Amaral Cassio Eduardo , Yoshida Maurício , de Souza Matheus Rodrigues , Fagundes Caroline Ferreira , Teixeira Manoel Jacobsen , Figueiredo Eberval Gadelha 
Published: March 2020

OBJECTIVEThe main objective of neurosurgery is to establish safe and reliable surgical techniques. Medical technology has advanced during the 21st century, enabling the development of increasingly sophisticated tools for preoperative study that can be used by surgeons before performing surgery on an actual patient. Laser-printed models are a robust tool for improving surgical performance, planning an operative approach, and developing the skills and strategy to deal with uncommon and high-risk intraoperative difficulties. Practice with these models enhances the surgeon’s understanding of 3D anatomy but has some limitations with regard to tactile perception. In this study, the authors aimed to develop a preoperative planning method that combines a hybrid model with augmented reality (AR) to enhance preparation for and planning of a specific surgical procedure, correction of metopic craniosynostosis, also known as trigonocephaly.METHODSWith the use of imaging data of an actual case patient who underwent surgical correction of metopic craniosynostosis, a physical hybrid model (for hands-on applications) and an AR app for a mobile device were created. The hybrid customized model was developed by using analysis of diagnostic CT imaging of a case patient with metopic craniosynostosis. Created from many different types of silicone, the physical model simulates anatomical conditions, allowing a multidisciplinary team to deal with different situations and to precisely determine the appropriate surgical approach. A real-time AR interface with the physical model was developed by using an AR app that enhances the anatomic aspects of the patient’s skull. This method was used by 38 experienced surgeons (craniofacial plastic surgeons and neurosurgeons), who then responded to a questionnaire that evaluated the realism and utility of the hybrid AR simulation used in this method as a beneficial educational tool for teaching and preoperative planning in performing surgical metopic craniosynostosis correction.RESULTSThe authors developed a practice model for planning the surgical cranial remodeling used in the correction of metopic craniosynostosis. In the hybrid AR model, all aspects of the surgical procedure previously performed on the case patient were simulated: subcutaneous and subperiosteal dissection, skin incision, and skull remodeling with absorbable miniplates. The pre- and postoperative procedures were also carried out, which emphasizes the role of the AR app in the hybrid model. On the basis of the questionnaire, the hybrid AR tool was approved by the senior surgery team and considered adequate for educational purposes. Statistical analysis of the questionnaire responses also highlighted the potential for the use of the hybrid model in future applications.CONCLUSIONSThis new preoperative platform that combines physical and virtual models may represent an important method to improve multidisciplinary discussion in addition to being a powerful teaching tool. The hybrid model associated with the AR app provided an effective training environment, and it enhanced the teaching of surgical anatomy and operative strategies in a challenging neurosurgical procedure.