Innovative Pediatric Simulator for Difficult Airway Management Training.

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Learn more: PMC Disclaimer | PMC Copyright Notice IEEE J Transl Eng Health Med . 2026 Mar 26;14:179–187. doi: 10.1109/JTEHM.2026.3677892 Search in PMC Search in PubMed View in NLM Catalog Add to search Innovative Pediatric Simulator for Difficult Airway Management Training Marta Mencarelli Marta Mencarelli 1 Pediatric Neuro-Oncology Unit, Meyer Children’s University Hospital, IRCCS, Florence, 50139, Italy Find articles by Marta Mencarelli 1, ✉ , Luca Puggelli Luca Puggelli 2 Department of Industrial Engineering, University of Florence, Florence, 50139, Italy Find articles by Luca Puggelli 2 , Roberto Baggi Roberto Baggi 3 Respiratory Endoscopy Unit, Meyer Children’s University Hospital, IRCCS, Florence, 50139, Italy Find articles by Roberto Baggi 3 , Stefano Avenali Stefano Avenali 3 Respiratory Endoscopy Unit, Meyer Children’s University Hospital, IRCCS, Florence, 50139, Italy Find articles by Stefano Avenali 3 , Francesca Amoretti Francesca Amoretti 4 Radiodiagnostic Unit, Meyer Children’s University Hospital, IRCCS, Florence, 50139, Italy Find articles by Francesca Amoretti 4 , Monica Carfagni Monica Carfagni 2 Department of Industrial Engineering, University of Florence, Florence, 50139, Italy Find articles by Monica Carfagni 2 , Yary Volpe Yary Volpe 2 Department of Industrial Engineering, University of Florence, Florence, 50139, Italy Find articles by Yary Volpe 2 , Paola Serio Paola Serio 5 Neuro-Anesthesiology Unit, Meyer Children’s University Hospital, IRCCS, Florence, 50139, Italy Find articles by Paola Serio 5 Author information Article notes Copyright and License information 1 Pediatric Neuro-Oncology Unit, Meyer Children’s University Hospital, IRCCS, Florence, 50139, Italy 2 Department of Industrial Engineering, University of Florence, Florence, 50139, Italy 3 Respiratory Endoscopy Unit, Meyer Children’s University Hospital, IRCCS, Florence, 50139, Italy 4 Radiodiagnostic Unit, Meyer Children’s University Hospital, IRCCS, Florence, 50139, Italy 5 Neuro-Anesthesiology Unit, Meyer Children’s University Hospital, IRCCS, Florence, 50139, Italy Corresponding Author: M. Mencarelli ✉ Corresponding author. Received 2025 Aug 1; Revised 2026 Feb 25; Revised 2026 Mar 23; Accepted 2026 Mar 23; Collection date 2026. © 2026 The Authors This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/ PMC Copyright notice PMCID: PMC13068112  PMID: 41970940 Abstract Objective: Pediatric airway management presents unique challenges, particularly in patients with congenital conditions that increase the risk of difficult intubation. Simulation offers a safe environment for clinicians to practice, yet current pediatric mannequins often lack pathological realism. This study aims to develop and validate a high-fidelity, patient-specific pediatric airway mannequin simulating difficult intubation associated with Crouzon syndrome. Technology or Method: A modular training mannequin was developed through CT-based modeling and additive manufacturing at the T3Ddy Laboratory, a collaboration between AOU Meyer Children’s Hospital–IRCCS and the University of Florence. Anatomical structures were segmented from CT and MRI scans of a 19-month-old patient with Crouzon syndrome. These 3-D models guided the design of a realistic airway, including nasal and oral access, a flexible tongue, and a movable jaw. Rigid parts were 3-D-printed; soft tissues were cast in silicones of varying hardness. Design choices were validated through iterative testing and refinement. Results: The simulator was evaluated during a pediatric bronchoscopy training course. Physicians assessed realism, tactile feedback, and usability via a Likert-scale questionnaire. Results indicated strong agreement on the mannequin’s effectiveness in replicating challenging intubation scenarios, particularly those requiring fiberoptic-guided techniques. Conclusion: This modular, patient-specific pediatric airway simulator provides a realistic, high-fidelity platform for training clinicians in difficult intubation techniques. Its anatomically accurate design enhances procedural confidence and skill acquisition, particularly for managing complex cases like those associated with Crouzon syndrome. Keywords: 3-D printing, additive manufacturing, Crouzon syndrome simulator, pathological airway, pediatric simulation Clinical Impact: The development of a patient-specific pediatric airway mannequin represents a significant translational advance, bridging engineering innovation and clinical education. By replicating complex anatomical features of Crouzon syndrome with high fidelity, the simulator enables realistic, pathologyspecific training in difficult airway management. Its clinical relevance is underscored by its potential to improve procedural proficiency, reduce patient risk, and enhance preparedness for rare and challenging scenarios in pediatric anesthesiology and emergency care. I. Introduction Clinical simulation is a valuable tool for medical and healthcare professionals to acquire or refine procedural knowledge while ensuring patient safety [1] , [2] . Both physical and virtual simulators recreate various scenarios, allowing practitioners to learn diagnostic and therapeutic techniques and reinforce medical concepts and workflows. This educational approach accelerates the learning process in a controlled environment, where trainees can learn from mistakes without risking patient well-being [3] . Adequate training is crucial when considering life-saving high-risk procedures such as endotracheal intubation (ETI), especially in pediatric patients, where physiological limits on safe apnea before complications are extremely reduced, and even more complicated for difficult airways [4] . Simulators are generally classified as high fidelity (HF) or low fidelity (LF) based on their characteristics [1] . LF simulators are typically easier to use and maintain, with lower anatomical accuracy, while HF simulators can reproduce complex and realistic scenarios due to their detailed anatomical parts. Beyond improving technical proficiency, high-fidelity simulation allows clinical teams to rehearse complex procedural sequences in a low-pressure environment. This facilitates collaborative planning and verbal coordination of airway management steps, bridging the gap between theoretical strategy and real-world execution, thereby minimizing the cognitive load during actual clinical crises. Despite advancements in simulation technologies, many educational mannequins for training on adult and pediatric patients still face limitations in anatomical accuracy, appropriate airway dimensions, and tissue mechanical properties [2] , [5] , [6] . These challenges are particularly pronounced in the design and production of HF pediatric mannequins, given their smaller dimensions and the complexity of reproducing accurate anatomical and physiological details. Pediatric mannequins are further constrained by limited commercial availability, as companies often prioritize “general-purpose” products or devices targeting high-sales markets to maintain competitive pricing. Consequently, mannequins designed specifically for pediatric pathological cases are scarce, with most commercially available devices representing healthy scenarios. Notably, no existing simulator has ever replicated the complex airway anatomy associated with Crouzon Syndrome, a critical gap addressed by this study. As highlighted by the medical staff at Meyer Children’s Hospital–IRCCS in Florence, Italy, pathological conditions that complicate airway management–such as mandibular hypoplasia (e.g., Pierre Robin sequence), limited mouth opening, macroglossia, and syndromes associated with facial asymmetry and anomalies (e.g., Crouzon syndrome)–are rarely considered. Among the limited pathological pediatric mannequins available, the AirSim Pierre Robin ( Trucorp , Armagh, Northern Ireland) is the only device designed to represent a medical condition complicating endotracheal intubation (ETI). It models a 6-month-old patient with Pierre Robin Syndrome, but it has not been widely adopted by the medical community, which criticized the insufficiently pronounced representation of the syndrome [7] , [8] . This underscores the need for more anatomically accurate and realistic pathological pediatric simulators to support training in challenging ETI scenarios, particularly for rare and complex conditions like Crouzon Syndrome, a critical area of concern emphasized by numerous studies [8] , [9] , [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] . Recent advances in CT-based modeling and additive manufacturing (AM) techniques have facilitated the development of custom-made mannequins tailored to specific training needs. Such mannequins have proven valuable not only for educational purposes but also as tools to explain surgical procedures to patients and their families [19] , [20] . Notable examples include Podolsky et al.’s high-fidelity cleft palate simulator [21] , Park et al.’s low-cost rigid bronchoscopy mannequin [22] , and Weatherall et al.’s healthy 21-month-old pediatric mannequin created using RE, AM, and silicone casting [11] . Another notable study in the field is that of Kanazawa, who demonstrated the utility of preoperative intubation simulation using custom-made 3D-printed simulators for pediatric patients with difficult airways, showing improved safety and accuracy during anesthesia induction [23] . Only a few studies focused on the development of pathological mannequins, respectively Mao et al., who developed a 3D-printed simulator for tracheal intubation in pediatric patients with Pierre Robin sequence, demonstrating its effectiveness in reducing intubation time and improving procedural confidence among anesthesiologists [24] , and Puggelli et al, who also proposed a modular 3D-printed pediatric mannequin with a high-fidelity difficult airway due to Pierre Robin sequence, demonstrating its effectiveness in training for fiberoptic-guided intubation [25] . Hybrid solutions have also been documented, such as Ramahi et al.’s pediatric tracheal model [5] and Kovatch et al.’s high-fidelity tracheal model for front-of-neck access training [13] . To address these limitations, this study presents a novel modular mannequin developed within the T3Ddy Laboratory , featuring patient-specific anatomy derived from a clinical case of Crouzon Syndrome. This approach advances the state-of-the-art through a modular architecture that allows for interchangeable pathological components (e.g., tracheostomy, stenosis) and the rapid replacement of worn parts. By combining 3D printing with silicone casting, the simulator achieves high anatomical accuracy and realistic tissue response. Building on previous experience with non-oral access models [25] , this new modular design supports both nasal and oral intubation, providing a versatile platform that can be iteratively expanded with new pathological modules to meet specific clinical training demands. II. Methods A. Layout Definition The device’s design is modular to allow for easy replacement of worn-out parts and to enable the simulation of different clinical scenarios using the same mannequin. The mannequin has been designed so that all lower-airway-related components are compatible with a previously developed one [25] , allowing the same parts to be used on both mannequins. Referring to Fig. 1 , the mannequin’s head is composed of 11 main internal parts: • Cranial Shells (1 and 2): these two-part shells form the outer structure of the skull. The split design allows for easy mounting, removal, and replacement of internal components. This feature facilitates customization of the mannequin to simulate different anatomical scenarios/conditions, providing flexibility for diverse training needs. • Upper Airways : made of silicone to closely replicate the feel and flexibility of real pediatric upper airways. The modular design enables the replacement to mimic specific pediatric conditions, such as airway obstructions or anatomical variations. • Hard Palate : embedded within the silicone upper airway, this rigid structure simulates the natural hardness of the palate. It provides tactile feedback during intubation, helping trainees recognize and navigate this anatomical feature. • Tongue : flexible and positioned realistically, it contributes to the realism of intubation practice. • Mandible : it guides and simulates the mouth-opening movement, assisting in scenarios such as the use of a laryngoscope or jaw thrust maneuvers. Its motion mirrors the biomechanics of the human jaw for realistic practice. • Lower Airways Joint : equipped with magnets, this joint facilitates faster assembly and disassembly of the airway components. This feature enhances the modularity and usability of the mannequin by enabling quick swaps or adjustments during training sessions. • Head Support : this component is part of a hinge system. The second part of the hinge is mounted on a plexiglass base and features an axial sliding mechanism that allows easy mounting and dismounting of the head. This design ensures stability and facilitates quick adjustments during training. • Tracheobronchial Tree : this component simulates the trachea and bronchi. It is interchangeable, allowing the mannequin to simulate various lower airway scenarios, such as obstruction or tracheomalacia. The modular design enables users to swap out the tracheobronchial tree quickly and efficiently, enhancing the versatility of the mannequin for diverse training scenarios. • Epiglottis : it provides a realistic representation of the epiglottis, serving as a key anatomical landmark for safe and effective intubation. • Vocal Cords : simulated pediatric vocal cords act as visual landmarks for verifying the proper placement of the endotracheal tube. FIGURE 1. Open in a new tab Mannequin’s layout. Epiglottis, Vocal Cords, and Tracheobronchial Tree , compose the Lower Airways subassembly. Both Epiglottis and Vocal Cords are designed as independent and replaceable parts, separate from the Tracheobronchial Tree . This is because the Epiglottis and Vocal Cords are more prone to wear and tear due to their limited dimensions and frequent use during training. They are also easier and cheaper to manufacture, making their replacement more practical. In contrast, the trachea is a more durable but difficult and expensive component to produce, justifying its independent design and extended lifespan. This ensures cost-effectiveness and longevity for the mannequin. The mannequin head is finally covered with the Skin component, a 5 mm-thick silicone layer designed to mimic the human skin. This component not only defines the aesthetic appearance of the mannequin’s face but also provides a realistic tactile experience. B. Segmentation and Modeling Anonymized CT and MRI images of a 19-month-old patient with Crouzon Syndrome, a rare genetic disorder characterized by premature craniosynostosis, facial dysmorphisms, and potential neurological complications, were provided through the collaboration of the medical staff at Meyer Children’s Hospital–IRCCS. Anatomical components were modeled through geometric reconstruction based on real patients’ images. The process begins by defining the Region of Interest (ROI) using selection tools based on Hounsfield Unit (HU) values. A draft voxel reconstruction is then refined using the Marching Cubes algorithm [26] to create polygonal geometry, which is exported in stereolithography (STL) format. Mimics Medical 21.0 software ( Materialise , Leuven, Belgium) was used for these steps, repeated for each anatomical region (skin, bone structure, palate, tongue, upper and lower airway lumen, epiglottis, and vocal cords). The error related to the geometric accuracy of the 3D reconstruction process has been estimated to be less than 0.2 mm in previous studies [25] , [27] , [28] . Further editing and modeling were done using Geomagic Design ( 3D Systems Inc ., Carolina, USA). The parts were modeled according to the previously defined layout. The Cranial Shells , fabricated from PLA via Fused Deposition Modeling (FDM), serve as the main housing for the Upper Airways component. To ensure precise modular integration, each shell features a shaped area for guiding the Mandible movement and a recessed slot for coupling with the Hard Palate ( Figure 2 ). Furthermore, Cranial Shells’ bottom incorporates magnets to facilitate a self-aligning connection with the lower airway joint. The assembly is secured using a combination of screws and threaded inserts, providing a stable and durable structural framework. FIGURE 2. Open in a new tab Semi-exploded view of the head assembly showing how the Upper Airways component is inserted into the Cranial Shells . The shaped are to guide the Mandible movement is also visible. Upper Airways component is made of silicone through mold casting. It includes the Hard Palate , placed directly into the mold before casting. The molds and Hard Palate are 3D-printed. This last is a 2 mm thick plate featuring a grid structure to facilitate integration with silicone. The Upper Airways also hosts the transverse section of the Mandible , allowing it to mimic the mouth aperture, which ranges from 10 to 25 mm. The mouth must be forced open, and when released, it closes naturally due to the elasticity of the silicone, simulating realistic behavior. The Upper Airways is rigidly integrated into the Cranial Shells to ensure absolute stability during the simulation of flexible fiberoptic intubation, where a non-mobile airway is preferred to allow the trainee to focus exclusively on endoscopic navigation and tip control without unwanted structural displacement. The mold design presented challenges due to the complexity of the inner cavities of the choanae and the oral cavity. To address this, the mold core was manufactured using FDM with soluble material ( Stratasys SR30 ). Due to the fragile behavior of this material, the core was further divided into three parts, to enable support-free printing and avoid the risk of breakage when removing supports. Tongue component was developed with input from medical staff to ensure anatomical and tactile realism. Made of a 00-50 Shore hardness silicone with a 3 mm wall thickness, its hollow geometry mimics natural collapsibility under pressure, preventing obstruction of medical instruments. Extensive testing refined its fixation system to the Upper Airways component to ensure stability during use, eliminating risks of detachment. This design provides realistic functionality and behavior for training scenarios. The Mandible reproduces jaw opening through a simplified mechanical hinge. It is pinned to the cranial shells via two lateral hinge holes (one per side), defining a rotation axis approximately aligned with the anatomical mandibular condyles. The Cranial Shells provide integrated end-stops that limit the mandible’s angular excursion, yielding a controlled mouth-opening range. The Upper Airways component is positionally constrained by the rigid Hard Palate insert and features a shaped interface that couples with the mandible by form fit. During opening, the mandible rotates freely about the hinge axis while guiding the deformation of the silicone Upper Airways ; this compliant deformation enables the motion without compromising the stability of the overall assembly. Figure 2 shows the semi-exploded view of the mannequin’s head’s internal structure. The Lower Airways Joint is a bell-shaped component divided into two hinged halves. Each half features a closed bottom with a central hole that allows the passage of the tracheal trait of the Tracheobronchial Tree and an open top, which ensures direct contact between the Upper Airways and Lower Airways , enabling proper alignment without gaps. Magnets around the open top provide a secure and quick connection to the mannequin head. This modular design allows for efficient replacement and reconfiguration of Lower Airways to simulate various training scenarios ( Fig. 3 ). FIGURE 3. Open in a new tab Lower Airways Joint shown in transparency (a) and mounted in the mannequin head (b). The Tracheobronchial Tree component is designed for realistic and practical simulation, with its lumen geometry derived from CT and MR images and then morphed and edited to optimize navigation. The modifications include analysis and adjusting cross-sectional dimensions to ensure compatibility with medical instruments. A minimum lumen diameter of 1.8 mm is present only at points of stenosis, while the rest of the airway accommodates fiberscopes up to 4 mm in diameter, making it suitable for various procedures. The lumen geometry has also been simplified compared to the original image-derived cases to reduce difficulty levels, ensuring the component remains suitable for medical student training ( Fig. 4 ). FIGURE 4. Open in a new tab Virtual model of the CT-derived version of the trachea, featuring no tracheal rings and a complex outer geometry (a), and the engineered version featuring tracheal rings and a less detailed external structure (b). The outer surface features cartilage rings, visible from inside the trachea, providing visual landmarks for orientation during navigation. In the trachea, the rings are positioned on the front side, aiding anatomical accuracy and realism. To simplify manufacturing, the outer shape has been streamlined to reduce the complexity of the mold, which uses a single-piece soluble core (made of Stratasys SR-30 soluble material) for precise lumen formation. The minimum wall thickness is 2 mm, ensuring durability while maintaining realism. These refinements were performed under the supervision and guidance of Meyer Children’s Hospital–IRRCS medical staff collaborating with the T3Ddy Laboratory , balancing anatomical fidelity and practical usability. In conjunction with the development of the mannequin and the redesign of the tracheobronchial tree, we addressed the general shortage of pathological simulation devices, particularly those targeting tracheal conditions. As a result, we have produced the first pathological modules, specifically designed to fit both mannequins we developed. These include models such as the trachea with tracheostomy, which illustrates the surgical creation of an opening in the trachea for respiratory support; the trachea with stenosis, representing a narrowing due to scar tissue formation; and the trachea with tracheoesophageal fistula, which simulates a connection between the trachea and esophagus that allows for the potential entry of saliva or food into the airways. Pathological tracheas are shown in Fig. 5 . FIGURE 5. Open in a new tab Fastening system. Finally, the focus was placed on the fastening system. By the layout specifications, two hooks were engineered on each side of the Cranial Shells , secured by pairs of screws and threaded inserts. To facilitate head movement while the mannequin is mounted on the base–a 12-millimeter-thick plexiglass panel–and to enable easy disassembly, two additional hooks with distinct geometries were created. Referring to Figure 5 , the left hook is anchored to the base with four screws, whereas the right hook was designed for sliding functionality, allowing it to detach easily once a fastening knob is loosened. This knob connects with a sliding plate located at the back of the base, enabling the head to be removed without the need for tools. The final configuration of the mannequin is illustrated in Fig 6 . FIGURE 6. Open in a new tab Virtual model of the mannequin with (a) and without the silicone layer simulating the skin (b). C. Assembly The entire mannequin is designed to be easily assembled and disassembled to facilitate the substitution of the damaged parts as well as the customization of the device itself by combining different pathological modules. The Hard Palate is designed to be incorporated into the Upper Airways during the silicone casting and it’s the only part that cannot be substituted without damaging another component, namely the Upper Airways . All the other parts are independent and assembled starting from the Upper Airways which is the core of the mannequin. The assembly begins with framing the Mandible and securing the Tongue with hooks. Cranial Shells are fastened with screws, and the Lower Airways is assembled, accommodating various Tracheobronchial Tree models. Magnetic connections allow efficient component replacement. The head attaches to the support system via hooks and screws, while the detachable base is secured with screws and a sliding mechanism. The Skin aligns using cranial reference points, and the mannequin is fixed by adjusting the slide and tightening the knob. D. Fabrication The mannequin parts were fabricated by AM and molding and casting techniques. Rigid parts corresponding to Cranial Shells , Hard Palate , Mandible , Lower Airways Joint , and molds for soft parts were realized in PLA using the FDM 3D printer i3 MK3S+ by Prusa Research (Prague, Czech Republic). Soluble cores for the Upper Airways and Tracheobronchial Tree were realized in SR-30 ( Stratasys Inc . Minnesota, USA) using FDM (Fused Deposition Modeling) 3D printer F370 by Stratasys Inc . (Minnesota, USA). SR-30 is a thermoplastic polymer that dissolves in a 60°C soda bath with a 2% concentration, without causing any damage to the platinum silicone used for the soft components. Hooks, slide, and joints of the support system were fabricated using a photopolymer resin White Resin ( Formlabs Inc ., Massachusetts, USA) using the SLA (Stereolithography) 3D printer Form3B by Formlabs Inc. (Massachusetts, USA) for better finishing. Depending on the part that had to be reproduced, parts corresponding to soft tissues were realized by silicone casting in 3D printed molds using different shore hardness silicone. Upper Airways , Epiglottis , Vocal Cords , and Tracheobronchial Trees were fabricated in Smooth Sil 940 ( Smooth-On Inc ., Pennsylvania), a pink platinum-cure silicone with a 40 Shore-A hardness, according to the results of previous studies [25] , [28] , [29] . The Upper Airways and Tongue were fabricated using Ecoflex 00-30 ( Smooth-On Inc ., Pennsylvania), a transparent platinum-cure silicone with a 30 Shore-00 hardness that can be colored using specific pigments according to specific needs. For casting the Skin , Ecoflex 00-50 ( Smooth-On Inc ., Pennsylvania), a transparent platinum-cure silicone with a 50 Shore-00 hardness, was added with a 10% thinning agent, Thinner ( Smooth-On Inc ., Pennsylvania), to facilitate the process, given the complexity of the mold and its reduced thickness. The molding and casting process follows the same steps, regardless of the type of silicone used. First, a silicone-free release agent is applied, and if necessary, the core is positioned before closing the mold. The liquid silicone compound is then prepared by mixing its two components according to the manufacturer’s specified ratios–1A:1B for Ecoflex 00-30 and 00-50 , and 100A:10B for Smooth-Sil 940 [30] –with colored pigments added as needed. After mixing, the compound is degassed using a vacuum pump to eliminate air bubbles and gently poured into the mold to prevent new bubbles from forming. Once fully cured, the silicone part can be removed from the mold. After inserting magnets and thread inserts where required, the mannequin can be used in different simulated scenarios. The production cycle follows a multi-day workflow. The additive manufacturing phase requires approximately 48–72 h of cumulative FDM printing time, depending on slicing parameters (e.g., layer height, infill, support density, and print speed) selected to ensure dimensional accuracy and surface quality. Dissolution of the SR-30 soluble cores in a C soda bath requires up to ~1 week, with duration influenced by internal geometry and bath conditions. Silicone casting and curing require an additional 24–48 h to ensure complete polymerization and dimensional stabilization prior to demolding and assembly. The workflow also includes manual operations (mold preparation, core positioning, degassing, controlled pouring, demolding, and insertion of magnets/threaded inserts), contributing to overall labor. The design incorporates manufacturability constraints (e.g., mold strategy and assembly interfaces); however, certain steps—particularly soluble-core dissolution and silicone curing—remain inherently time-dependent due to material and process physics. In Fig. 7 , the assembled mannequin, ready to be used and during fiberoptic-guided intubation simulation, is shown. FIGURE 7. Open in a new tab Assembled mannequin (a), and simulation of fiberoptic-guided intubation for expected difficult airways using the mannequin (b). E. Evaluation Questionnaire The validation process for the developed mannequin was conducted in two complementary phases to ensure both expert technical feedback and broader clinical applicability. First, eight expert physicians with extensive experience in airway management tested the mannequin in a controlled setting. They evaluated the simulator’s realism and confirmed its suitability for simulating a difficult intubation scenario requiring fiberoptic techniques. Subsequently, the simulator was used in a certified clinical training course on pediatric bronchoscopy at Meyer Children’s Hospital–IRCCS. While the pediatric bronchoscopy course encompassed various hands-on sessions including both rigid and flexible techniques, the proposed simulator was specifically designed and utilized for flexible fiberoptic intubation in a pathological airway scenario. Other skills, such as foreign body removal via rigid bronchoscopy, were practiced on different models. During this course, 20 physicians, including residents and senior anesthesiologists, respiratory endoscopists and intensivists, otolaryngologists, neonatologists, in-hospital and out-of-hospital emergency physicians, pneumologists, and pediatricians, performed procedures using the mannequin and completed a structured evaluation questionnaire. The course focused on essential skills in flexible and rigid bronchoscopy for pediatric airway management. The training, performed in a realistic clinical setting, emphasizes fiberoptic-guided intubation for expected difficult airways and rigid bronchoscopy for foreign body extraction. Participants engaged in focused lectures, video case analyses, and hands-on sessions with advanced simulators and 3D-printed models to ensure proficiency in managing pediatric airways safely in both routine and emergencies. During the course, 20 physicians attempted intubation using the simulator and anonymously completed a structured evaluation questionnaire based on a 5-point Likert scale (0 = not evaluable, 1 = strongly disagree, 2 = disagree, 3 = neutral, 4 = agree, 5 = strongly agree) featuring the 14 statements reported in Table 1 to which express the agreement level. TABLE 1. Sentences (S) reported in the questionnaire. S1 The anatomical geometry of the upper airways is accurately reproduced. S2 The anatomical geometry of the tracheobronchial tree is accurately reproduced. S3 The endoscopic view is accurately reproduced. S4 Inserting the equipment feels realistic. S5 Haptic/tactile feedback is adequate. S6 The difficulty level provided by the simulator is adequate. S7 The simulator is comfortable and easy to use. S8 The simulator is a valuable training tool. S9 My ability to perform fiberscope-guided intubation has improved after using the simulator. S10 Training on the simulator may lead to a higher safety level for the patients. S11 Training on the simulator may speed up the fiberscope-guided intubation procedure on real patients. S12 The overall procedure is realistic. S13 I advise the use of the mannequin to teach new procedures before intervening on real patients. S14 I advise the use of the mannequin for attendings and residents to improve and maintain their procedural skills. Open in a new tab The questionnaire was designed to assess three key aspects: the anatomical and functional realism of the mannequin (S1-S3), the fidelity of the simulated scenario (S4-S6), and the perceived clinical relevance for training in difficult pediatric airway management (S7-S14). The questionnaire was the same one used for the evaluation of another mannequin for difficult airway management featuring different characteristics [25] , and aimed to evaluate the realism of the mannequin, the realism of the simulation, and its usefulness. A comment section was also provided. The average age of the 20 physicians who filled out the questionnaire after the simulation session featuring the developed mannequin was 45.1 years. 45% (9 out of 20) were male, 55% 11 out of 20) were female, and were residents (20%) and attendings (80%) with previous experience on fiberscope-guided intubations on real patients. More details about participants’ professional expertise can be found in Fig. 8 . The results obtained by averaging the responses can be considered satisfactory (details are provided in Figure 9 , left). FIGURE 8. Open in a new tab Participants’ professional expertise in terms of seniority, and previous fiberscope-guided intubations on real patients with and without supervision. FIGURE 9. Open in a new tab Mean accordance with the 14 statements (S) proposed in the questionnaire (left) and mean scores obtained in the three categories (C) corresponding to the realism of the simulator (orange), the realism of the simulation (yellow), and the overall experience (green). Mean values were calculated for each of the three evaluated categories (simulator realism, simulation realism, and overall satisfaction), as shown in Figure 9 , right. For all statements the mean scores exceed 4, indicating general agreement on the proposed statements regarding the adequacy of the simulator’s realism, the realism of the simulation, and the overall experience. No comments were provided by the participants. III. Discussion The first validation of the device was obtained through feedback from pediatric anesthesiologists, otolaryngologists, and respiratory endoscopists who had the opportunity to perform ETI on the mannequin during a bronchoscopy course at Meyer Children’s Hospital–IRCCS. The results were satisfactory in terms of anatomical geometry, component dimensions, and the mouth opening system. The mannequin has been assessed as providing an anatomically accurate representation of the airway in pediatric patients affected by orofacial malformations that complicate intubation with routinely used devices, marking the first successful replication of Crouzon Syndrome in a training simulator–the validation of the device underscored its technical and educational innovation. The modular design for rapid reconfiguration of pathological scenarios (e.g., tracheoesophageal fistula, stenosis), a feature absent in commercial simulators, received positive feedback from clinicians. Beyond the anatomical structure, the medical staff positively evaluated the tactile feedback provided by the selected materials, confirming that the compliance of real tissues is correctly reproduced. The use of patient-specific geometries from Crouzon Syndrome CT scans ensures anatomical fidelity, while the hybrid fabrication (PLA for rigid structures, variable Shore hardness silicones for soft tissues) replicates tactile feedback with high precision. The realism and difficulty level presented by the simulation were also well received. Notably, the magnetic coupling system for the lower airway joint and the soluble-core molding technique for complex lumens represent significant engineering advancements. Regarding the acquisition of bronchoscope-guided intubation skills using the mannequin, all course participants were assessed by a single expert to eliminate potential evaluation biases. Notably, all participants demonstrated proficiency in the technique on their first attempt. The overall user experience results were highly satisfactory. However, there is room for improvement, particularly in enhancing the realism of instrument passage. Optimizing the lubrication process could address this issue, as lubrication is currently administered manually via the oral cavity, similar to other simulators. Since only instrument lubrication is part of the actual procedure, integrating an onboard lubrication system within the mannequin could ensure thorough lubrication of the airway, further enhancing procedural realism and consistency. From the engineering perspective, ongoing research focuses on finding an alternative to SR-30 for fabricating the airway and tracheal cores using soluble materials. Although dissolution in a 2% soda solution is effective, the required time of approximately one week is unacceptably long. This is due to the very small hole dimensions limiting solution penetration but enlarging them would compromise the anatomical realism of the model. IV. Conclusion This study presents a significant advancement in pediatric airway simulation by introducing a modular, patient-specific mannequin that combines anatomical accuracy, functional realism, and versatility. Key innovations include a scalable, modular system for simulating diverse pathologies, advanced fabrication techniques, and validated tactile feedback through material science. These contributions pioneer the simulation of rare and complex conditions like Crouzon Syndrome, filling a critical gap in pediatric training and establishing a framework for future simulator development. Based on a two-phase validation involving both expert evaluation and formal clinical training, the developed modular mannequin is an innovative and highly valuable tool with the potential to expand simulation-based training to clinically challenging scenarios. The translational value of this modular simulator lies in its ability to bridge the gap between theoretical anatomical knowledge and bedside procedural skills. By utilizing patient-specific CT data to generate pathological modules, the platform allows clinicians to practice high-risk maneuvers—such as fiberoptic intubation in Crouzon Syndrome—in a zero-risk environment that accurately replicates the tactile and anatomical challenges encountered in the operating theater. This shift from generic training to patient-specific simulation represents a significant advancement in clinical education, potentially reducing procedural complications and improving safety outcomes in pediatric difficult airway management. Future developments aim to create more advanced and comprehensive mannequins featuring additional characteristics and tailored for various training tasks, including cervical mobility for direct laryngoscopy maneuvers. Using CT-based modeling and AM techniques, different pathological modules could be combined and interchanged according to the needs of the medical and surgical staff. Based on the current assessment, the developed modular mannequin is an innovative and highly valuable tool with the potential to expand simulation-based training to clinically challenging scenarios. References [1]. 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