Validation of a 3D printed Silicone-based Laryngeal Model for Resident Education

Abstract

Objective:

We sought to validate a laryngeal simulation model and subsequently demonstrate its efficacy in improving surgical technique.

Study Design:

Pre-post Interventional Study

Setting:

Otolaryngology Program at a Tertiary Care Center

Methods:

A low-cost, high-fidelity laryngeal model was created using a 3D-printed cast and multi-layered silicone to mimic vocal fold lesions. Participants (attendings & trainees) were first given a series of tasks including mucosal vocal fold lesion resection and micro-flap excision of a submucosal lesion. Trainees were then provided with an instructional video from a laryngologist and asked to repeat the same tasks on the model. Performance data was then assessed using validated surveys and blinded expert reviewers.

Results:

Eighteen participants completed the simulation. All subjects agreed that the “simulation experience was useful” and 93% agreed “the simulator helped improve my ability to do microsurgical tasks.” In the post-instruction self-evaluation, trainees reported a significant decrease in mental demand (95%CI: 0.37–0.91; p=0.038) and significant increase in subjective performance (95%CI: 1.51–51.89; p=0.016) compared to the pre-instruction self-evaluation. On the post-instruction attempt, there was a significant improvement in all domains of the adapted Objective Structured Assessment of Technical Skills (OSATS) as measured by three blinded, expert reviewers.

Discussion:

This study demonstrates the usefulness of a silicone larynx model and the value of instructional video in developing laryngeal microsurgical skills. Participants positively reviewed the laryngeal model and trainees saw both a subjective and objective improvement indicating tangible operative benefits from the use of this laryngeal simulation.

INTRODUCTION

Simulation is an important learning tool in surgery, with substantial evidence supporting the value of simulation in surgical training.^1-3 Simulators provide several advantages over traditional patient-based clinical and procedural training, such as the ability to practice in low-stakes environments, simulating uncommon or challenging procedures, and allowing the trainee to isolate specific techniques and skills in a targeted and time-efficient manner.^1,4

In otolaryngology, trainees are faced with learning a broad array of surgical techniques, made more challenging due to the diversity of procedures within the specialty. Many otolaryngologic procedures, in particular endoscopic procedures, are primarily single-surgeon operations with a low tolerance for surgical error, which can make teaching and learning more difficult. For example, in laryngeal microsurgery, only one individual can operate under the microscope while manipulating microsurgical instruments in the narrow confines of the laryngoscope. Manipulating these rigid instruments with long lever arms, distant end effectors, and minimal tolerance for error requires numerous repetitions to acquire technical proficiency. Additionally, these procedures rely on subtle visual and tactile cues which can be challenging to learn by observation alone.⁴

For a multitude of reasons, simulation in otolaryngology can be highly valuable and has been previously used for training in a variety of ear, nose, and throat procedures, including myringotomy tube placement, sinus surgery, peritonsillar abscess drainage, mastoidectomy, and phonomicrosurgery.⁵ Despite an abundance of simulation studies in otolaryngology, further development and standardization is needed in laryngology and phonomicrosurgery.

The conventional modes of teaching laryngeal surgery, primarily based on cadaveric dissection, two-dimensional illustrations, or institution-dependent operating room experience often fall short in providing a comprehensive, hands-on learning experience. For example, in a survey study of 191 residents by Shah et al., only 18.8% of residents were “very” satisfied with their phonomicrosurgery experience and 87.4% felt that their comfort level with phonomicrosurgery would increase if they had access to laboratory-based training.⁶

This limitation has prompted the exploration of alternative modalities for surgical education. Various simulation tools have been specifically developed for applications in laryngology.^4,7-14 These simulators can be broadly classified into three categories: cadaveric (animal or human) models, low-cost fabricated models, and high-fidelity 3D-printed models. Cadaveric models may best approximate living human tissue. However, cadaveric tissue is expensive, has limited utility due to its processing and preservation, typically lacks pathology, and animal larynges may differ from human anatomy.^9,10,14,15 Simple, low-cost models, such as those relying on rubber bands, fabric, paper, or grapes are readily accessible but typically have lower fidelity and face validity.^12,15,16

3D printing has emerged over the last several decades as an indispensable tool in rapid prototyping.^17-19 Recently, Lee et al. developed an open-source, 3D-printed laryngeal model using images from a computed tomography scan to develop a 3D-printed cast for silicone injection molding.⁴ This model addressed the pitfalls of many of the prior models and laid the groundwork for future studies to develop realistic operating room simulations with high face validity and content validity that would be beneficial for surgical education.

The goal of creating a low-cost, modular, reproducible, adaptable laryngeal simulator with high face, content, and construct validity remains somewhat elusive. To that end, we created a high-fidelity, low-cost, silicone larynx model, using a modified open-source 3D-printed larynx mold with additional modular features to achieve improved and varied simulations. By bridging the gap between theory and practice, this novel model aims to enhance the educational experience, accelerate skill acquisition, and ultimately improve patient outcomes. Herein we demonstrate the utility and validity of this larynx model for resident education in laryngeal microsurgical procedures.

METHODS

Model Development

A laryngeal cast was 3D printed using an UltiMaker printer (UltiMaker B.V., Geldermalsen, The Netherlands) and PLA filament. STL files for the cast were based on a previously published open-source design that was created using computed tomography scans of the upper airways processed with 3D Slicer and refined in Blender and Fusion 360, as previously described.⁴ The cast was scaled by 1.15x on Ultimaker Cura to more closely approximate the size of the adult glottis and allow for surgical access with a standard laryngoscope. Our model adapted from Lee et al can be found online at wikifactory.com/@ucsdent/larynx-model/files. Silicone injection molding was then completed. Smooth-On Oomoo silicone (EcoFlex^™ 00-20) was mixed and then injected into the 3D-printed cast using a 60 mL Luer lock syringe. The silicone was allowed to cure for at least 2 hours and then removed from the cast. Given the consistent proportions of silicone used, all model consistencies were identical to one another.

Subsequently, a 3D-printed mold was used to create standardized lesions. Silicone was placed, dyed red using Smooth-On Slic Pig silicone pigment and cured in the mold. The lesion was designed as a small, ovoid subepithelial mass and affixed to the right vocal fold using silicone adhesive. A thin silicone film was then cut to cover the right vocal fold and lesion of the silicone model. This was then affixed over the silicone vocal fold using silicone adhesive, simulating a submucosal lesion. The model was then rigidly suspended using 3D-printed parts.

Study Design & Simulated Tasks

Approval for this study was obtained from the UCSD Institutional Review Board (#808922). Participants were included if they were otolaryngology residents who were currently in training or current otolaryngology faculty. Participants were given details about the simulation prior to their participation. Upon arrival, they were first assessed for their level of comfort and experience with laryngeal surgery on a 5-point Likert Scale. They were provided with standard microlaryngeal instruments and both vocal folds of the model were visualized through a Dedo laryngoscope using a laryngeal microscope (Figure 1A). All tasks were video recorded. Participants were then instructed to raise a micro-flap, remove the sub-epithelial lesion, and lay the microflap back down without trimming (Figure 1B, Figure 1C). Once completed, attendings rated their overall experience with the model, and resident experience was assessed using the NASA Task Load Index and Michigan Standard Simulation Experience Scale (MiSSES) to assess the face validity, content validity and construct validity of the model (Supplementary Figure 1).²⁰ Residents were then provided with an instructional video of a fellowship-trained laryngologist completing the same task. Following the video, residents were given a new larynx model and completed the same task a second time. Resident experience was again assessed by evaluating their overall experience with the model and using the NASA Task Load Index (NASA TLX) and the MiSSES questionnaire to determine if there were differences in subjective performance between the first and second trials.

Figure 1:

A) Microlaryngeal simulator set up with a laryngeal microscope, Dedo laryngoscope and silicone laryngeal model B) Microscope view of a participant raising a microflap. C) Image of the model with the lesion affixed to the vocal cord prior to placement of the silicone flap over the lesion

Performance Assessment

The NASA TLX and MiSSES are validated questionnaires that are designed to measure performance and preferences in a simulation environment.²¹ The NASA TLX questionnaire assesses the user on multiple domains: comfort, mental demand, physical demand, temporal demand, performance, effort, and frustration. The MiSSES assesses the value of the simulation model looking at self-efficacy (construct validity), fidelity (face validity), educational value (content validity), and overall impressions. In addition to the above, residents were evaluated on time to completion of the task and times before and after viewing the instructional video were compared. Lastly, resident videos were evaluated by three blinded laryngologists. All videos were randomized and blinded, with all participant information removed from the videos. An objective structured assessment of technical skills (OSATS) was adapted from the standard OSATS used by residency programs and prior laryngeal research.²² The OSATS form was completed for each microflap task that each participant completed. The first part of the OSATS assessed task-specific performance evaluating instrument handling, initial incision, raising of the microflap, and resection of the sub-epithelial lesion. The second part of the assessment rated global operative performance. (Supplementary Figure 2).

Statistical Analysis

Descriptive statistics including means, medians, and frequencies were calculated as appropriate. The simulation was first assessed for overall experience, realism of the model, and use of the model as a training tool. Participants rated each category on a 5-point Likert scale from strongly disagree to strongly agree. Univariate analysis was then completed comparing laryngeal comfort/experience and post-graduate year (PGY) to task times, MiSSES scores, and overall experience. To evaluate the impact of watching the expert dissection video, paired t-tests were used to compare pre-intervention (trial 1) and post-intervention (trial 2) groups. Ordered logistic regressions were used when analyzing ordinal variables from the MiSSES and OSATS and were corrected for subjective level of comfort with laryngeal. Intraclass correlation coefficient (ICC) estimates between raters on the OSATS were calculated based on a two-way random-effects model. Post-hoc subgroup analysis was completed to determine if there were significant differences in subjective and objective improvement based on PGY. For this analysis, we compared trial 1 and trial 2 NASA TLX, MiSSES and OSATS scores in junior residents alone (PGY 1-3) and then in senior residents alone (PGY 4-5). STATA v18 (StataCorp, College Station, Texas) was used for analyses and p-values of less than 0.05 were considered significant.²³

RESULTS

Study Participants

Eighteen people completed the laryngeal simulation (Table 1). There were 9 junior residents (3 PGY-1, 3 PGY-2, 3 PGY-3), 5 senior residents (3 PGY-4, 2 PGY-5), and 4 attendings. Eight females and 10 males participated. Sixteen participants (89%) were right-handed. Most residents reported “minimal experience” (10/14; 71%) with any type of microlaryngeal surgery. This experience paralleled comfort with laryngeal surgery, with 7 residents (50%) reporting “minimal comfort” with microlaryngeal surgery and 4 residents (29%) reporting “not at all comfortable” with microlaryngeal surgery.

Table 1.

Demographics and Experience

N	18
Male:Female	10:8
Training Year
- PGY 1-3	9 (50%)
- PGY 4-5	5 (28%)
- Attending	4 (22%)
Right-Handed	16 (89%)
Experience with Any Laryngeal Surgery (n=14)*
- No Experience	2 (14%)
- Minimal Experience	8 (57%)
- Moderate Experience	4 (29%)
Comfort with Any Laryngeal Surgery (n=14)*
- Not at all Comfortable	4 (29%)
- Minimally Comfortable	7 (50%)
- Moderately Comfortable	3 (21%)

^*Experience and Comfort were assessed in residents only; PGY: post-grad year

Laryngeal Model Evaluation

All participants (attendings and trainees; 18/18) agreed that the overall simulation was useful (Figure 2). Sixteen participants (16/17; 94%) agreed that the “simulation had adequately realistic characteristics and features.” 17 participants (94%) agreed that the “simulation environment and the laryngeal tissue were adequately realistic.” All participants (18/18) agreed that the “realism of the surgical tasks was adequate.” All participants agreed that the “simulation was a good training tool for skills in laryngeal surgery” and 17 participants (94%) agreed that “the simulation was a good training tool for knowledge in laryngeal surgery.” Similarly, 17 participants (94%) agreed that “the simulator was critical to addressing how to perform phonomicrosurgery” and “addressing basic ergonomics and techniques in microlaryngeal surgery.”

Figure 2:

Overall evaluation of the simulation model. All categories including realistic features, usefulness as a training tool, and overall experience were well reviewed by participants.

Resident Assessment of the Simulation as an Educational Tool

On initial assessment, most participants reported that the simulation required high mental demand (8/14; 57%), medium physical demand (7/14; 50%) and low temporal demand (8/14; 57%) (Table 2). Thirteen participants (93%) rated their performance on the initial simulation as very low, low, or medium. Thirteen (93%) reported medium, high, or very high levels of frustration. There was no association between any domains on the NASA TLX & MiSSES and comfort level with laryngeal surgery (p>0.05).

Table 2:

Median NASA Task Load Index Scores for Participants Compared by Post-Grad Year (PGY)

	Trial 1 (SD)			Trial 2 (SD)
	Overall	PGY1-3	PGY4-5	Overall	PGY1-3	PGY4-5
Mental Demand	4 (0.7)	4 (0.5)	4 (1)	3.5 (0.7)*	4 (0.7)*	3 (0.8)
Physical Demand	3 (0.9)	4 (1)	3 (0.9)	3 (0.5)	3 (0.5)	3 (0.4)
Temporal Demand	2 (0.8)	2 (0.5)	3 (1)	2 (0.6)	2 (0.6)	3 (0.5)
Subjective Performance	3 (0.9)	2 (0.8)	3 (0.5)	3 (0.7)*	3 (0.7)*	3 (0.9)
Effort	4 (0.7)	4 (0.7)	4 (0.8)	4 (0.5)	3 (0.5)*	4 (0)
Frustration	3 (0.8)	4 (0.7)	3 (0.9)	2 (0.6)*	2 (0.6)*	2 (0.5)

^*p<0.05; All variables had a max of 5 with higher scores indicating increased demand, subjective performance, increased effort, and increased frustration

On repeat assessment, there was a significant decrease in self-reported mental demand (95% CI: 0.37 – 0.91; p=0.038). There was also a significant increase in subjective performance (95% CI: 1.51 – 51.89; p=0.016). Lastly, there was a significant decrease in frustration in the post evaluation (95% CI: −8.57 - −3.23; p<0.001) (Figure 3). All variables remained significant when correcting for comfort with laryngeal surgery. When performing a sub-group analysis based on junior (PGY 1-3) and senior (PGY 4-5) residents, mental demand, subjective performance, and frustration showed similar results when looking at junior residents alone. However, when looking at senior residents alone, there were no differences between trial 1 and trial 2 in any domains of the NASA TLX or MiSSES, though this was limited by only five senior residents being included in this sub-analysis.

Figure 3:

NASA Task Load Index and Michigan Standard Simulation Experience Scale (MiSSES) variables showing a significant decrease in mental demand and frustration and increase in subjective performance between Trial 1 and Trial 2.

Time to complete each task was also measured. Participants completed the task in an average of 13:34 minutes (SD 5:09 min). After the instructional video, participants completed the task in an average of 12:12 minutes (SD 5:47 min). On unadjusted analysis, there was no change in task completion time between trial 1 and trial 2 (p=0.26). This was similar when adjusting for comfort with laryngeal surgery (p=0.12).

OSATS Evaluation

Operative videos were then reviewed by three blinded fellowship-trained laryngologists and rated using an OSATS described above. ICC was determined to be 0.88 indicating good interrater reliability. Performance significantly improved in all categories of the OSATS in the post-intervention group (Table 3; Figure 4). The mean total OSATS score improved from 17.4 to 31.7 (Mean difference: 14.3; p<0.001). Improvement was also seen in task-specific performance scores (6.4 to 12.5; p<0.001) and global performance scores (11.0 to 19.2; p<0.001). These findings remained significant after correcting for comfort with laryngeal surgery. When analyzing junior residents (PGY 1-3) and senior residents (PGY 4-5) separately, we saw a trend towards more improvement in overall OSATS scores in senior residents over junior residents, though this did not reach statistical significance (senior mean improvement: 17.0; junior mean improvement: 11.5; p=0.14). Both groups had significant improvements in all domains of the OSATS and total scores.

Table 3:

OSATS Scores by Post-Grad Year (PGY) Level

	Trial 1 (SD)			Trial 2 (SD)
	Overall	PGY1-3	PGY4-5	Overall	PGY1-3	PGY4-5
Task- Specific Performance
- Initial Incision	1.7 (1.0)	1.4 (0.6)	2.2 (1.3)	3.6 (1.0)*	3.6 (1.1)*	3.7 (0.9)*
- Microflap - superficial aspect	1.6 (0.7)	1.5 (0.6)	1.6 (0.8)	3.0 (0.9)*	2.8 (0.9)*	3.4 (0.7)*
- Microflap - deep aspect	1.6 (0.8)	1.6 (0.7)	1.7 (0.8)	3.1 (1.2)*	2.9 (1.2)*	3.5 (0.9)*
- Resects Lesion	1.5 (0.7)	1.5 (0.6)	1.7 (0.9)	2.8 (1.1)*	2.5 (1.1)*	3.3 (0.9)*
Global Performance
- Instrument Handling	2.0 (0.8)	1.9 (0.8)	2.2 (0.9)	3.2 (1.0)*	3.0 (1.0)*	3.5 (0.7)*
- Respect for Tissue	1.9 (0.8)	1.8 (0.7)	1.9 (0.9)	3.1 (0.9)*	2.9 (0.8)*	3.5 (1.0)*
- Time & Motion	1.9 (0.9)	1.9 (0.9)	1.9 (1.1)	3.2 (1.1)*	2.9 (1.0)*	3.5 (1.0)*
- Procedure Knowledge	1.8 (0.8)	1.7 (0.8)	1.9 (0.8)	3.4 (1.1)*	3.2 (1.2)*	3.8 (0.9)*
- Flow of Operation	1.8 (0.8)	1.7 (0.8)	2 (1.0)	3.2 (1.2)*	2.9 (1.2)*	3.7 (0.9)*
- Overall Performance	1.5 (0.9)	1.5 (0.8)	1.6 (0.8)	3.1 (1.2)*	2.8 (1.2)*	3.7 (0.9)*
Total Score	17.4 (6.2)*	16.6 (5.3)	18.9 (7.4)	31.7 (9.5)*	29.4 (9.7)*	35.9 (7.8)*

^*p<0.001; All variables other than total score had a max of 5 with higher scores indicating increased improved performance. Scores significantly improved in all domains.

Figure 4:

OSATS scores compared between trials. 3A: Overall Scores between trial 1 and trial 2 showing an overall significant improvement. 3B: Global Performance Domains showed a significant improvement in all domains 3C: Task-Specific Domains showed a significant improvement in all domains. 3D: Overall scores by resident year with improvements in overall scores in both junior and senior residents

DISCUSSION

Over the past few decades, the utilization of simulation models in the education of otolaryngology trainees has been increasing.⁵ Despite this progress, there exists significant potential for improvements in the creation of laryngeal simulators—ones that are not only cost-effective and modular but also capable of delivering highly realistic surgical experiences across a spectrum of procedures. The imperative lies in developing robust simulators and establishing standardized training protocols. In response to this training gap, we have devised and implemented an accurate 3D model tailored for laryngeal microsurgical training.

For our simulation model, we utilized an easily reproducible and low-cost 3D printed model that participants felt closely approximated tissue interactions in a human larynx, as evidenced by 94% of participants noting that the simulation had realistic characteristics and that the laryngeal tissue was adequately realistic. Our results demonstrated several favorable outcomes to this novel training experience. All trainees reported that the experience led to increases in knowledge and 93% felt that the experience helped improve their ability to complete microsurgical tasks. On the post-instruction attempt, participants had a significant decrease in mental demand and an increase in subjective performance indicating the subjective educational benefit of this laryngeal model and educational video. In addition, objective assessment revealed significant improvement in trainee technical skills following the training.

Several other laryngeal simulators have been described in recent years with variable features relative to realistic features, cost, and rigorous evaluation.^{7,14-16,22,24-26}. Many laryngeal simulators that have been designed involve simple models developed from PVC tubing, acrylic plates, rubber bands, plastic wraps, or grapes.^14-16,24 For example, Holliday et al. and Santander et al. created a laryngeal model out of PVC pipes.^15,24 While low-cost and easily reproducible, these types of models have multiple limitations. Most notably, these models lack the complex anatomy of the larynx and thus are limited in teaching procedural steps. While Holliday et al. and Santander et al. both subjectively determined that their models had a high face validity, their model was limited by their materials used for their construct and further advancements in 3D-printing have allowed us to create a model that allows trainees to better learn laryngeal anatomy and the procedural steps of laryngeal surgery. These previously described models can help teach basic microsurgical ergonomics but are limited with respect to the laryngeal microsurgical tasks that can be completed. Using a multi-layered silicone model, we sought to mimic the vocal fold’s multi-layered structure to help participants understand the importance of preserving the epithelium, dissect within the superficial lamina propria, and preserve the deeper layers when performing phonomicrosurgery. While silicone is not a perfect match for the consistency of the vocal folds, participants felt that the consistency of the model was sufficiently realistic for a surgical training model. This also allowed us to provide participants with realistic tasks that are directly applicable to their time in the operating room.

Another significant limitation to current laryngeal models is cost and accessibility. Numerous studies have utilized an animal larynx for laryngeal microsurgical practice.^10,27-34 While these models provide tissue quality and feel similar to a human larynx, they can be difficult to access and costly to obtain, with the few studies that discussed cost citing over $100 per larynx model.^32-34 These high costs were similar in various synthetic models, with costs reported as high as $2000 for the creation of a laryngeal simulation station, though cost comparison with these prior studies may be limited due to changes in material costs over time.^14,24,26 However, the model developed in this paper again addresses these limitations. First, because the cast was made using 3D printing, any institution with access to a 3D printer can produce this model. Second, our model uses only 3D-printed filament and injected silicone, making it extremely low-cost (approximately $3/model) and easy to reproduce. While our study used a standard Dedo laryngoscope, future implementations can use any tubing of a similar size or a previously described 3D-printed laryngoscopes to mimic a laryngoscope aperture and decrease costs associated with developing multiple laryngeal simulation stations.³³

Lastly, the efficacy of the simulation model was assessed using both subjective and objective assessments before and after training, allowing quantitative assessment of the model as a learning tool. This separates our methodology from many other simulation studies, which often only include descriptive or qualitative data and fail to evaluate the efficacy of the model as a training tool.^13,15,25,25 There are a few studies that have used objective assessments in their evaluation of their model, but none of these studies evaluated their model as a tool for resident education using a pre-validated evaluation such as the OSATS making a direct comparison difficult.¹⁴ Using a verified subjective assessments such as the NASA TLX and MiSSES combined with an objective OSATS substantiated the results in our study since participants improved both subjectively and objectively from trial 1 to trial 2. Similarly, allowing trainees multiple attempts to practice on the laryngeal model allowed us to complete a pairwise comparison of the benefit of this simulation for each individual trainee.

Simulation is most effective as an adjunct to current educational tools and does not replace the need for other forms of instruction including manuscripts, textbooks, and instructional videos. Given that many otolaryngology trainees rely on online resources such as published protocols and YouTube videos,³⁵ our methodology demonstrates the efficacy of using simulation models as an adjunct to current learning tools rather than a replacement. By providing students with an instructional video before repeating the simulation, we sought to mimic one version of the current learning environment and demonstrated that our laryngeal model can serve as an adjunct to improve trainee learning. Therefore, the improvements seen between trial 1 and trial 2 are likely due to both the instructional video as well as repeated practice using the laryngeal simulation.

Our study primarily involved trainees with minimal experience in laryngeal surgery. Although we had a diverse range of participants across different PGY levels, most described themselves as having minimal comfort, and there were no significant objective differences in OSATS scores between junior and senior residents. Often, resident involvement in these procedures is limited to more senior residents given the necessary technical skill set and a low tolerance for surgical error which limits early exposure and subsequent comfort with these interventions. This underscores the complexity of phonomicrosurgery and emphasizes the need for additional simulation training in laryngology.

A major limitation of the study is the number of participants, with a sample size of 18. However, this is similar to most studies describing simulation models and our power analysis adapted from prior studies indicated that our sample size was sufficient to detect significant differences. Despite the small sample size, the study was still able to detect significant differences in NASA TLX, MiSSES and OSATS scores. To increase the size of future studies, a multi-institutional design would allow for more trainees to experience this model. The high fidelity, low cost, and reproducibility of this model would make the feasible.

An additional limitation of the study is that while silicone models molded using 3D printing techniques have many benefits over other materials (decreased cost, closer consistency to the human larynx), silicone is limited in its ability to perfectly mimic the tactile sense of working with laryngeal tissue. However, as the sophistication of 3D printing techniques increases and costs decrease, we hope to continue to improve on the physical limitations of the current model. For example, it may be possible to use additive manufacturing to 3D print the model directly using softer filament, rather than print a mold and inject it with silicone. Regardless, simulation remains a critical and underutilized tool for learning challenging and highly specialized surgical techniques.

CONCLUSION

Our 3D-printed laryngeal simulator has a unique combination of strengths as a training tool for otolaryngology residents. These features include the ease and inexpensive production of the model, good simulation of human larynx tissue features, and quantitative assessment of simulation efficacy using standardized objective measures.

Supplementary Material

Supinfo1

Supplementary Figure 1: Survey given to participants including the NASA Task Load Index (NASA TLX) and the Michigan Standard Simulation Experience Scale (MiSSES).

Supinfo2

Supplementary Figure 2: Modified Objective Structured Assessment of Technical Skills (OSATS) use to evaluate the completion of a Microflap with resection of a subepithelial lesion