1. Austin S. Rose, MD 1, Julia S. Kimbell, PhD 1, Caroline E. Webster 2, Ola L.A. Harrysson, PhD 2, Eric J. Formeister, MS 1 and Craig A. Buchman, MD 1 1 Department of Otolaryngology-Head & Neck Surgery, University of North Carolina School of Medicine 2 Department of Industrial and Systems Engineering, North Carolina State University ABSTRACT As additive manufacturing, or 3D printing, has become more practical and affordable, a number of applications for the technology in the field of Otolaryngology-Head & Neck Surgery, and for pediatric otolaryngology in particular, have been considered. One area of promise may be in temporal bone surgical simulation. In this project, 3D models of pediatric temporal bones were created from de-identified temporal bone computed tomography (CT) scans using biomedical image processing software and ultimately printed in a variety of materials. The various models created were drilled in a temporal bone laboratory and graded by attending otolaryngologists on their anatomical accuracy and suitability of materials in regard to simulation of bone and other anatomy. Simulated temporal bones created through this process may be of potential benefit in surgical training, especially where cadaver bones are less available, pre-operative simulation for difficult otologic cases, and in standardized testing of temporal bone surgical skills. REFERENCES 1.Khemani S, Arora A, Singh A, Tolley N, Darzi A. Objective skills assessment and construct validation of a virtual reality temporal bone simulator. Otol Neurotol 2012; 33(7):1225- 1231 2.Demiryurek D, Bayramoglu A, Ustacelebi S. Infective agents in fixed human cadavers: a brief review and suggested guidelines. Anat Rec (New Anat) 2002; 269:194-197 3.Mick PT, Arnoldner C, Mainprize JG, Symons SP, Chen JM. Face validity study of an artificial temporal bone for simulation surgery. Otol Neurotol 2013; 34(7):1305-1310 4.Hochman JB, Kraut J, Kazmerik K, Unger BJ. Generation of a 3D printed temporal bone model with internal fidelity and validation of the mechanical construct. Otolaryngol Head Neck Surg 2014; 150(3):448-454 INTRODUCTION Simulation in medical and surgical education allows for learning and development of skills in a realistic, yet safe environment A surgical simulation should reproduce the visual, auditory and haptic characteristics of the actual procedure Better surgical simulations will help to address the problem of decreasing patient contact time, as well as reduced surgical volume and experience, among residents Cadaveric temporal bones are traditionally used to simulate otologic surgery, though pediatric specimens are rare Other drawbacks include safety and possible exposure to infectious agents and formaldehyde 2 Cost varies widely and may be prohibitive in some countries where specimens are in short supply due to financial or cultural issues Cadaveric temporal bones can not be standardized for testing or customized for teaching or pre-operative simulation A detailed, pediatric temporal bone model using 3D design and printing was proposed Challenges included the ability to adequately simulate highly detailed bony and soft tissue anatomy and the use of realistic materials Hypothesis: A simulated pediatric temporal bone can be created using 3D printing that will prove both safe and beneficial in training An Objet350 Connex printer was used with varying ratios of multiple proprietary thermoset polymers This allowed for unique biomechanical properties and colors for different anatomic structures Eight attending otolaryngologists were recruited for dissection of simulated pediatric temporal bones A 10 question Likert scale survey was completed by each participant for validity study RESULTS The simulated pediatric temporal bone model displayed significant bony detail and incorporated a range of color and physical characteristics for different anatomic structures (see Figure 2) Participants reported no irritation during dissection The average rating for overall value as a surgical simulation in preparation for cases in the OR was 4.4 (see Figure 3) DISCUSSION Challenges persist, including improvements in anatomic detail and the use of more realistic materials Examples of other reported materials include paper and plaster powder with cyanoacrylate 3 Hochman et al describe a novel slicing algorithm for the potential problem of support material filling void spaces during printing 4 We report the use of multiple materials in the printing process, achieving unique colors and physical properties for different structures Potential benefits of a pediatric 3D model for temporal bone surgical simulation: Standardization for education and testing Customization for unusual cases Pre-operative simulation Safer for trainees Improved patient outcomes and safety Increased supply of models, especially when compared with cadaver temporal bones for which pediatric specimens are rarely available CONCLUSIONS The results of this study support the hypothesis that a simulated pediatric 3D temporal bone can be created with significant value in otologic training and education, while remaining safe and easy to use. While other approaches exist, including injection-molded plastic models, cadaveric dissection and computer-based VR simulations, the use of 3D design and printing offers a number of potential advantages. METHODS DICOM data from high resolution CT scans of the temporal bone in children less than 12-months-old were imported into Mimics image-processing software (see Figure 1) Segmentation of bone, facial nerve, sigmoid sinus and internal carotid artery was performed Stereolithography (STL) files were then generated for printing of physical models Developing a 3D Model for Pediatric Temporal Bone Surgical Simulation Figure 1 (Clockwise from upper left ) - DICOM data from a 9-month-old child imported into Mimics image processing software with segmentation of bone  Creation of soft tissue structures  Lateral aspect of simulated temporal bone with zygomatic arch (ZA) external auditory canal (EAC)  Medial aspect of simulated temporal bone with sigmoid sinus (SS) and facial nerve (FN) in the internal auditory canal Figure 2 (Clockwise from upper left ) - Dissection of simulated pediatric temporal bone in standard temporal bone laboratory  Malleus viewed through the external auditory canal in simulated temporal bone  Horizontal semicircular canal (HSC), facial recess (FR), facial nerve (FN) and sigmoid sinus (SS) following dissection of simulated temporal bone  Intra-operative view from a left pediatric temporal bone for comparison Figure 3. Likert scale questionnaire used for validity EAC ZA SS FN malleus HSC FR FN SS FR