Development and Validation of a Low-Cost Three-Dimensional-Printed Simulator for Bronchial and Pulmonary Vascular Reconstruction Training.

In the operating room, the margin for error is non-existent. Surgeons must master intricate maneuvers, such as reconnecting airways and blood vessels inside the chest, where the space is tight and the tissues are delicate. Traditionally, learning these skills has relied on observing experts, practicing on animal tissues, or working with human cadavers. While valuable, these methods have significant drawbacks: animal models are expensive and ethically complex, cadavers are scarce and cannot be reused, and watching an expert does not always translate to the ability to perform the task oneself. To bridge this gap, medical educators have turned to simulation, creating artificial environments where trainees can make mistakes and learn without risk. The challenge has been creating models that feel and behave like real human tissue without costing a fortune or requiring specialized factories to produce them.

A team of researchers in Spain has addressed this challenge by developing a new, affordable training tool for thoracic surgery. They created a simulator designed specifically for the complex task of reconstructing the bronchial tubes and pulmonary arteries. The device is built using a two-step manufacturing process that combines the precision of 3D printing with the realistic feel of medical-grade silicone. First, the team used computer software to design the exact shapes of the airways and blood vessels. They then printed rigid molds of these shapes using a standard plastic printer. Once the molds were ready, they poured liquid silicone into them. When the silicone hardened, it formed flexible, durable replicas of the human anatomy that could be stitched and manipulated just like real tissue. The entire setup, including a platform that mimics the confined space of a chest cavity, cost approximately 114 euros to produce, making it accessible to hospitals and training centers with limited budgets.

To test whether this low-cost device actually worked as a teaching tool, the researchers invited 36 participants to use it. The group included medical students with basic training, surgical residents who were in the middle of their specialty training, and senior thoracic surgeons who had spent years performing these complex operations. Each participant was asked to perform specific tasks on the simulator, such as sewing the airway and blood vessels back together using both interrupted and continuous stitching techniques. They performed these tasks in two ways: first on a flat table where they had full access to the model, and second through the restricted platform that simulated the tight, difficult view of an actual surgery. The researchers measured how long it took to complete the tasks and whether the stitches were successful, while also asking the participants to rate how realistic the model felt and how useful it was for learning.

The results showed that the simulator successfully distinguished between the different levels of experience. When the tasks were performed in the open, unrestricted setting, almost everyone could complete the stitching. However, when the participants had to work through the restricted platform, a clear pattern emerged. The senior surgeons completed the difficult tasks at a much higher rate than the residents, who in turn performed better than the medical students. For example, when attempting a continuous stitch on the blood vessel inside the restricted platform, only 7.7 percent of the students succeeded, compared to 70 percent of the residents and 92.3 percent of the senior surgeons. This ability to separate the performance of novices from experts is a crucial sign that the simulator is a valid tool for assessing skill. It suggests that the device is difficult enough to reveal the true technical proficiency of the user.

Beyond just testing skill, the study also looked at how practice affected performance. When participants used the simulator repeatedly, they became significantly faster. The average time to complete a procedure dropped from over 960 seconds on the first attempt to roughly 858 seconds on the second. The most dramatic improvements were seen in the less experienced participants, who gained speed quickly with practice, while the experts, who were already fast, showed smaller gains. This indicates that the simulator allows for deliberate practice, where repetition leads to tangible improvements in efficiency. The participants also rated the simulator highly for its realism. They agreed that the texture of the silicone felt like real tissue and that the model was suitable for teaching and assessing surgical skills. Even the most experienced surgeons, who are often the most critical judges of such tools, found the simulator to be a realistic representation of the procedures they perform daily.

The researchers noted that while the simulator is excellent for practicing the mechanical act of stitching, it cannot replicate every aspect of human biology. The silicone does not bleed, it does not have blood flow, and it does not heal or become inflamed like living tissue. These are limitations that the authors acknowledge, as the device is designed for technical skill acquisition rather than simulating the full physiological response of a patient. Despite these constraints, the study concludes that this approach offers a practical and reproducible way to train surgeons. By combining 3D-printed molds with reusable silicone, the team has created a system that is cheap enough to be used frequently and robust enough to withstand repeated use. This work suggests that high-quality surgical training does not need to be prohibitively expensive, and that accessible tools can play a vital role in preparing the next generation of surgeons for the complex challenges of thoracic reconstruction.