Review of temporal bone dissection teaching: how it was, is and will be

3D 4K Exo-Endoscopic Temporal Bone Dissection: A Novel Approach for Sharing the Anatomy

BACKGROUND

Temporal bone dissection is overwide recognized as an ideal training method for otologic surgeons. The knowledge of temporal bone anatomy and especially of the course of infratemporal facial nerve is pivotal in practice. The 3D exoscope is an innovative and promising tool, that was recently introduced in ear surgery.

METHODS

A high-definition 3D exoscope (3D VITOM®) mounted on the VERSACRANETM holding system (Karl Storz) was used to perform two temporal bone dissection, with the aim to study the anatomy of infratemporal facial nerve. The 3D endoscope (TIPCAM®1 S 3D ORL, Karl Storz) was used in combination to provide a close-up high-quality view and to provide a different angle of view on fine anatomical relationships.

RESULTS

The high-definition 3D exoscope allowed to conduct the dissection with high quality visualization and to share the same surgical field with trainees. Moreover, it showed a high interchangeability with the 3D endoscope.

CONCLUSIONS

3D 4 K Exo-endoscopic temporal bone dissection seems to have benefits in terms of educational purpose, especially concerning anatomy understanding. The superiority in teaching value of this tool should be further investigated in cohort studies.

Recent advances in Otology: Current landscape and future direction

Hearing is an essential sensation, and its deterioration leads to a significant decrease in the quality of life. Thus, great efforts have been made by otologists to preserve and recover hearing. Our knowledge regarding the field of otology has progressed with advances in technology, and otologists have sought to develop novel approaches in the field of otologic surgery to achieve higher hearing recovery or preservation rates. This requires knowledge regarding the anatomy of the temporal bone and the physiology of hearing. Basic research in the field of otology has progressed with advances in molecular biology and genetics. This review summarizes the current views and recent advances in the field of otology and otologic surgery, especially from the viewpoint of young Japanese clinician-scientists, and presents the perspectives and future directions for several topics in the field of otology. This review will aid next-generation researchers in understanding the recent advances and future challenges in the field of otology.

[Online training for hearing implant surgery : A new approach to otological training. German version]

OBJECTIVE

Education in microsurgery of the ear includes staged training to allow for mastering of the complex microsurgical procedures, particularly in the context of middle ear reconstruction and cochlear implantation. Traditional surgical training includes temporal bone preparations by cadaver dissection and supervised operating room practice. As these on-site trainings are limited, there is a need to broaden education facilities in an on-line format. Therefore, a first basic on-line training for otosurgery was developed.

MATERIALS AND METHODS

The system consists of an artificial temporal bone model together with a set of basic surgical instruments and implant dummies. As an essential part of the training kit, a high-resolution camera set is included that allows for connection to a video streaming platform and enables remote supervision of the trainees' surgical steps by experienced otological surgeons. In addition, a pre-learning platform covering temporal bone anatomy and instrumentation and pre-recorded lectures and instructional videos has been developed to allow trainees to review and reinforce their understanding before hands-on practice.

RESULTS

Over the three courses held to date, 28 participants with varying levels of prior surgical experience took part in this otological surgical training program. The immediate feedback of the participants was evaluated by means of a questionnaire. On this basis, the high value of the program became apparent and specific areas could by identified where further refinements could lead to an even more robust training experience.

CONCLUSION

The presented program of an otosurgical online training allows for basal education in practical exercises on a remote system. In this way, trainees who have no direct access to on-site instruction facilities in ear surgery now have the chance to start their otosurgical training in an educational setting adapted to modern technologies.

Quality and haptic feedback of three-dimensionally printed models for simulating dental implant surgery

STATEMENT OF PROBLEM

A model offering anatomic replication and haptic feedback similar to that of real bone is essential for hands-on surgical dental implant training. Patient-specific skeletal models can be produced with 3-dimensional (3D) printing, but whether these models can offer optimal haptic feedback for simulating implant surgery is unknown.

PURPOSE

The purpose of this trial was to compare the haptic feedback of different 3D printed models for simulating dental implant surgery.

MATERIAL AND METHODS

A cone beam computed tomography image of a 60-year-old man with a partially edentulous mandible was manipulated to segment the mandible and isolated from the rest of the scan. Three-dimensional models were printed with 6 different printers and materials: material jetting-based printer (MJ, acrylic-based resin); digital light processing-based printer (DLP, acrylic-based resin); fused filament fabrication-based printer (FFF1, polycarbonate filament; FFF2, polylactic acid filament); stereolithography-based printer (SLA, acrylic-based resin); and selective laser sintering-based printer (SLS, polyamide filament). Five experienced maxillofacial surgeons performed a simulated implant surgery on the models. A 5-point Likert scale questionnaire was established to assess the haptic feedback. The Friedman test and cumulative logit models were applied to evaluate differences among the models (α=.05).

RESULTS

The median score for drilling perception and implant insertion was highest for the MJ-based model and lowest for the SLS-based model. In relation to the drill chips, a median score of ≥3 was observed for all models. The score for corticotrabecular transition was highest for the MJ-based model and lowest for the FFF2-based model. Overall, the MJ-based model offered the highest score compared with the other models.

CONCLUSIONS

The 3D printed model with MJ technology and acrylic-based resin provided the best haptic feedback for performing implant surgery. However, none of the models were able to completely replicate the haptic perception of real bone.

Creation of a Prototype Cochlear Training Model

OBJECTIVE

Creation of a novel 3D-printed physical cochlear model that demonstrated the feasibility of creating the model, and impact of a Graphical User Interface (GUI) system on training insertion metrics.

STUDY DESIGN

Feasibility study with a pilot prospective data collection.

SETTING

Tertiary academic center.

METHODS

The study was IRB exempt. Five resident trainees (PGY1-PGY5) practiced electrode insertions in cadaveric temporal bones before using the simulator. Nine students were educated on how to hold the electrodes and position them, and then allowed to use the simulator. All trainees were instructed that slower insertions were favorable. One cochlear implant (CI) surgeon used the simulator. The GUI captured the real video feed, but also provided distance, trajectory, and velocity measurements. The program is designed to plot the real-time depth of insertion and speed of insertion of the electrode; the user is also provided real-time occurrence of any kinks and back-outs.

RESULTS

A total of 14 trainees and 1 CI surgeon inserted the electrode at least 5 times without the use of the GUI (before) and then at least 5 times with the use of the GUI (after). Average Speed before and after (100.84 and 53.23 mm/s); Average minimum speed before and after (59.34 and 9.65 mm/s); and Average maximum speed before and after (416 and 285.81 mm/s). Statistically significant improvements were noted in all the measured speeds of insertion (P < .001). The other variables improved but not to a statistical significance.

CONCLUSIONS

Real-time training using the 3D-printed model and GUI for cochlear implantation can help improve surgical resident training and comfort levels with electrode insertion for surgical trainees. The advantage of this model is that surgeons/trainees can use it as many times as they like, as the whole set-up is easy, economical, and reusable. The real time graphical user interface enhances training and retention of the practiced skills.

Trainee-perceived benefits of a virtual temporal bone competition

OBJECTIVE

To assess the perceived benefits of a novel educational approach for otolaryngology trainees: a virtual reality temporal bone simulator drilling competition.

METHODS

Regional otolaryngology trainees participated in the competition. Drilling activities using the Voxel-Man TempoSurg simulator were scored by experts. Questionnaires that contained questions covering motivators for attending, perceived learning and enjoyment were sent to participants. Agreement with statements was measured on a 10-point Likert scale (1 = strongly disagree, 10 = strongly agree).

RESULTS

Eighteen trainees participated. The most cited reason for attending was for learning and/or education (61 per cent), with most attendees (72 per cent) believing that competition encourages more reading and/or practice. Seventeen attendees (94 per cent) believed Voxel-Man TempoSurg-based simulation would help to improve intra-operative performance in mastoidectomy (mean 7.83 ± 1.47, p < 0.001) and understanding of anatomy (mean 8.72 ± 1.13, p < 0.001). All participants rated the competition as 'fun' and 83 per cent believed the competitive element added to this.

CONCLUSION

The virtual reality temporal bone competition is a novel educational approach within otolaryngology that was positively received by otolaryngology trainees.

Impact of virtual reality training on mastoidectomy performance: a prospective randomised study

PURPOSE

The opportunities for surgical training and practice in the operating room are in decline due to limited resources, increased efficiency demands, growing complexity of the cases, and concerns for patient safety. Virtual reality (VR) offers a novel opportunity to enhance surgical training and provide complementary three-dimensional experience that has been usually available in the operating room. Since VR allows viewing and manipulation of realistic 3D models, the VR environment could enhance anatomical and topographical knowledge, in particular. In this study, we explored whether incorporating VR anatomy training improves novices' performance during mastoidectomy over traditional methods.

METHODS

Thirty medical students were randomized into two groups and taught mastoidectomy in a structured manner. One group utilized a VR temporal bone model during the training while the other group used more traditional materials such as anatomy books. After the training, all participants completed a mastoidectomy on a 3D-printed temporal bone model under expert supervision. Performance during the mastoidectomy was evaluated with multiple metrics and feedback regarding the two training methods was gathered from the participants.

RESULTS

The VR training method was rated better by the participants, and they also needed less guidance during the mastoidectomy. There were no significant differences in operational time, the occurrence of injuries, self-assessment scores, and the surgical outcome between the two groups.

CONCLUSION

Our results support the utilization of VR training in complete novices as it has higher trainee satisfaction and leads to at least as good results as the more traditional methods.

Fully immersive virtual reality for skull-base surgery: surgical training and beyond

PURPOSE

A virtual reality (VR) system, where surgeons can practice procedures on virtual anatomies, is a scalable and cost-effective alternative to cadaveric training. The fully digitized virtual surgeries can also be used to assess the surgeon's skills using measurements that are otherwise hard to collect in reality. Thus, we present the Fully Immersive Virtual Reality System (FIVRS) for skull-base surgery, which combines surgical simulation software with a high-fidelity hardware setup.

METHODS

FIVRS allows surgeons to follow normal clinical workflows inside the VR environment. FIVRS uses advanced rendering designs and drilling algorithms for realistic bone ablation. A head-mounted display with ergonomics similar to that of surgical microscopes is used to improve immersiveness. Extensive multi-modal data are recorded for post-analysis, including eye gaze, motion, force, and video of the surgery. A user-friendly interface is also designed to ease the learning curve of using FIVRS.

RESULTS

We present results from a user study involving surgeons with various levels of expertise. The preliminary data recorded by FIVRS differentiate between participants with different levels of expertise, promising future research on automatic skill assessment. Furthermore, informal feedback from the study participants about the system's intuitiveness and immersiveness was positive.

CONCLUSION

We present FIVRS, a fully immersive VR system for skull-base surgery. FIVRS features a realistic software simulation coupled with modern hardware for improved realism. The system is completely open source and provides feature-rich data in an industry-standard format.

Evaluation of polyethylene terephthalate glycol (PETG), Simubone™, and photopolymer resin as 3D printed temporal bone models for surgical simulation

OBJECTIVES

Among types of 3D printing, fused deposition modeling (FDM) and digital light processing (DLP) are the most accessible, making them attractive, low-cost options for simulating surgical procedures. This study characterized and compared inexpensive, synthetic temporal bone models printed using Resin, PETG, and Simubone™.

MATERIALS AND METHODS

This study compared models made of polyethylene terephthalate glycol (PETG), Simubone™ produced from a FDM printer, and photopolymer resin from a DLP printer. These temporal bone models were processed by: (1) DICOM files from a patient's CT scan were segmented to define critical parts expected in a temporal bone surgery. (2) The model was appended with a base that articulates with a 3D-printed temporal bone holder. (3) The refined, patient-specific model was manufactured using FDM and DLP printing technologies. (4) The models were sent to evaluators, who assessed the models based on anatomic accuracy, dissection experience, and its applicability as a surgical simulation tool for temporal bone dissection.

RESULTS

The photopolymer resin outperformed PETG and Simubone™ in terms of anatomical accuracy and dissection experience. Additionally, resin and PETG were evaluated to be appropriate for simple mastoidectomy and canal wall down mastoidectomy while Simubone™ was only suitable for simple mastoidectomy. All models were unsuitable for posterior tympanotomy and labyrinthectomy.

CONCLUSIONS

Photopolymer resin and PETG have shown to be suitable materials for dissection models with 3D-printed resin models showing more accuracy in replicating anatomical structures and dissection experience. Hence, the use of 3D-printed temporal bones may be a suitable low-cost alternative to cadaveric dissection.

3-D-Printed Models for Temporal Bone Training: A Validity Study

OBJECTIVE

3-D printing offers convenient and low-cost mastoidectomy training; nonetheless, training benefits using 3-D-printed temporal bones remain largely unexplored. In this study, we have collected validity evidence for a low-cost, 3-D-printed temporal bone for mastoidectomy training and established a credible pass/fail score for performance on the model.

STUDY DESIGN

A prospective educational study gathering validity evidence using Messick's validity framework.

SETTING

Seven Danish otorhinolaryngology training institutions.

PARTICIPANTS

Eighteen otorhinolaryngology residents (novices) and 11 experienced otosurgeons (experts).

INTERVENTION

Residents and experienced otosurgeons each performed two to three anatomical mastoidectomies on a low-cost, 3-D-printed temporal bone model produced in-house. After drilling, mastoidectomy performances were rated by three blinded experts using a 25-item modified Welling scale (WS).

MAIN OUTCOME MEASURE

Validity evidence using Messick's framework including reliability assessment applying both classical test theory and Generalizability theory.

RESULTS

Novices achieved a mean score of 13.9 points; experienced otosurgeons achieved 23.2 points. Using the contrasting groups method, we established a 21/25-point pass/fail level. The Generalizability coefficient was 0.91, and 75% of the score variance was attributable to participant performance, indicating a high level of assessment reliability. Subsequent D studies revealed that two raters rating one performance or one rater rating two performances were sufficiently reliable for high-stakes assessment.

CONCLUSION

Validity evidence supports using a low-cost, 3-D-printed model for mastoidectomy training. The model can be printed in-house using consumer-grade 3-D printers and serves as an additional training tool in the temporal bone curriculum. For competency-based training, we established a cut-off score of 21 of 25 WS points using the contrasting groups method.

Development of a navigable 3D virtual model of temporal bone anatomy

BACKGROUND

Computed Tomography (CT) scanning offers an accurate structural definition of bones, blood vessels, and soft tissues; however, mental integration of cross-sectional 2D CT images for a 3D understanding of complex anatomical structures becomes difficult when the field of view is confined to the temporal bone. This project tried to provide a feasible solution to this problem by creating a navigable 3D virtual model which may aid in better comprehension of the temporal bone anatomy.

METHODS

A helical-CT scan was used to obtain high-resolution cross-sectional slices of a cadaveric human temporal bone. Using the volume-rendering capabilities of 3D Slicer^®, which involves volume data management, cropping of the data set, and threshold painting, detailed anatomical structures were segmented based on the intensity captured from different regions. This volumetric data was converted to an interactive virtual model using Blender^®.

RESULTS

The final product is a web page that allows interaction and navigation with a 3D annotated model of the temporal bone, which can be accessed from any device with a web browser.

CONCLUSION

This model can function as a training tool for students, teachers, and practitioners to understand and review the complex anatomy of the temporal bone.

Thinking Beyond the Temporal Bone Lab: A Systematic Process for Expanding Surgical Simulation in Otolaryngology Training

The COVID-19 pandemic led to a temporary lapse in the development of otolaryngology trainee operative skills due to the cancellation of elective procedures and redeployment of trainees and attendings to COVID-19 units. Although transient, this disruption provided an opportunity for otolaryngology programs to develop contingency plans and formalize nascent simulation training curricula. Integration of formal simulation training alongside current didactic and surgical education may offset lost exposure during surgically lean times while providing the framework and resources for enhanced baseline training. Here, we provide an up-to-date overview of surgical simulation models in otolaryngology and identify easily implementable, low-cost, low fidelity models for junior trainees. By taking advantage of rapid advancements in technology and a paradigm shift to a more hands-on approach in medical education, formal simulation training may prove to be a beneficial tool at all stages of residency training, allowing for expanded peer-mentored skill development and providing a safe haven during unforeseen disruptions in surgical case volume.

Effect of 3D-Printed Models on Cadaveric Dissection in Temporal Bone Training

Objective

Mastoidectomy is a cornerstone in the surgical management of middle and inner ear diseases. Unfortunately, training is challenged by insufficient access to human cadavers. Three-dimensional (3D) printing of temporal bones could alleviate this problem, but evidence on their educational effectiveness is lacking. It is largely unknown whether training on 3D-printed temporal bones improves mastoidectomy performance, including on cadavers, and how this training compares with virtual reality (VR) simulation. To address this knowledge gap, this study investigated whether training on 3D-printed temporal bones improves cadaveric dissection performance, and it compared this training with the already-established VR simulation.

Study Design

Prospective cohort study of an educational intervention.

Setting

Tertiary university hospital, cadaver dissection laboratory, and simulation center in Copenhagen, Denmark.

Methods

Eighteen otorhinolaryngology residents (intervention) attending the national temporal bone dissection course received 3 hours of mastoidectomy training on 3D-printed temporal bones. Posttraining cadaver mastoidectomy performances were rated by 3 experts using a validated assessment tool and compared with those of 66 previous course participants (control) who had received time-equivalent VR training prior to dissection.

Results

The intervention cohort outperformed the controls during cadaver dissection by 29% (P < .001); their performances were largely similar across training modalities but remained at a modest level (~50% of the maximum score).

Conclusion

Mastoidectomy skills improved from training on 3D-printed temporal bone and seemingly more so than on time-equivalent VR simulation. Importantly, these skills transferred to cadaveric dissection. Training on 3D-printed temporal bones can effectively supplement cadaver training when learning mastoidectomy.

Hand Motion Analysis Illustrates Differences When Drilling Cadaveric and Printed Temporal Bone

OBJECTIVE

Temporal bone simulation is now commonly used to augment cadaveric education. Assessment of these tools is ongoing, with haptic modeling illustrating dissimilar motion patterns compared to cadaveric opportunities. This has the potential to result in maladaptive skill development. It is hypothesized that trainee drill motion patterns during printed model dissection may likewise demonstrate dissimilar hand motion patterns.

METHODS

Resident surgeons dissected 3D-printed temporal bones generated from microCT data and cadaveric simulations. A magnetic position tracking system (TrakSTAR Ascension, Yarraville, Australia) captured drill position and orientation. Skill assessment included cortical mastoidectomy, thinning procedures (sigmoid sinus, dural plate, posterior canal wall) and facial recess development. Dissection was performed by 8 trainees (n = 5 < PGY3 > n = 3) using k-cos metrics to analyze drill strokes within position recordings. K-cos metrics define strokes by change in direction, providing metrics for stroke duration, curvature, and length.

RESULTS

T-tests between models showed no significant difference in drill stroke frequency (cadaveric = 1.36/s, printed = 1.50/s, P < .40) but demonstrate significantly shorter duration (cadaveric = 0.37 s, printed = 0.16 s, P < .01) and a higher percentage of curved strokes (cadaveric = 31, printed = 67, P < .01) employed in printed bone dissection. Junior staff used a higher number of short strokes (junior = 0.54, senior = 0.38, P < .01) and higher percentage of curved strokes (junior = 35%, senior = 21%, P < .01).

CONCLUSIONS

Significant differences in hand motions were present between simulations, however the significance is unclear. This may indicate that printed bone is not best positioned to be the principal training schema.

3D-4K exoscope-assisted temporal bone dissection: a new frontier in surgical training

PURPOSE

To assess if 3D-4K exoscope is a valuable tool for temporal bone dissection and to evaluate its teaching potential.

METHODS

Six consecutive 3D-4K-exoscope-assisted cortical mastoidectomies were performed by a novice, an intermediate and an expert surgeon (two dissections each). All dissections were entirely recorded and later evaluated independently by three other experienced surgeons. The dissection end-product was evaluated according to the Melbourne Mastoidectomy Scale (MMS). Paired t test was used to assess whether novice and intermediate surgeons have a score improvement in the second dissection compared to the first one. Surgeons' interactions, depth effect, and 3D impression were also assessed to perform a subjective analysis.

RESULTS

Mean MMS scores for the novice, intermediate and expert surgeon were 11.3 ± 2.8, 13.8 ± 3.9 and 19 ± 1.3, respectively. Paired t test demonstrated a statically significant improvement between the first and the second dissection both for the novice and the intermediate surgeon (+ 4.7 and + 7 points; p = 0.0002). A high-quality magnification of the temporal bone was obtained, allowing the expert surgeon to identify all the anatomical structures without injuring them. The exoscope was capable of providing a high involvement in the dissections with very effective interactions between the expert surgeon and the trainees, that had access to the same surgical field view.

CONCLUSION

3D-4K-exoscope resulted adequate for a safe and effective mastoidectomy and showed a high potential for training and educational purposes. It can represent a valid option for surgical training of temporal bone dissection and a new interactive tool to understand the complex temporal bone anatomy.

Automated summative feedback improves performance and retention in simulation training of mastoidectomy: a randomised controlled trial

OBJECTIVE

This study aimed to investigate the effects of automated metrics-based summative feedback on performance, retention and cognitive load in distributed virtual reality simulation training of mastoidectomy.

METHOD

Twenty-four medical students were randomised in two groups and performed 15 mastoidectomies on a distributed virtual reality simulator as practice. The intervention group received additional summative metrics-based feedback; the control group followed standard instructions. Two to three months after training, participants performed a retention test without learning supports.

RESULTS

The intervention group had a better final-product score (mean difference = 1.0 points; p = 0.001) and metrics-based score (mean difference = 12.7; p < 0.001). At retention, the metrics-based score for the intervention group remained superior (mean difference = 6.9 per cent; p = 0.02). Also at the retention, cognitive load was higher in the intervention group (mean difference = 10.0 per cent; p < 0.001).

CONCLUSION

Summative metrics-based feedback improved performance and lead to a safer and faster performance compared with standard instructions and seems a valuable educational tool in the early acquisition of temporal bone skills.

Three dimensional printing of a low-cost middle-ear training model for surgical management of otosclerosis

BACKGROUND

Surgical management of otosclerosis is technically challenging with studies demonstrating that outcomes are commensurate with surgical experience. Moreover, experts apply less force on the ossicular chain during prosthesis placement than their novice counterparts. Given the predicted decreasing patient pool and the rising cost of human temporal bone specimens it has become more challenging for trainees to receive adequate intraoperative or laboratory-based experience in this procedure. As such, there is a need for a low-cost training model for the procedure. Here we describe such a model.

METHODS

A surgical model of the middle ear was designed using computer aided design (CAD) software. The model consists of four components, the superior three dimensional (3D)-printed component representing the external auditory canal, a 90° torsion spring representing the incus, a 3D-printed base with a stapedotomy underlying the torsion spring, and a 3D-printed phone holder to facilitate video-recording of trials and subsequent calculation of the force applied on the modeled incus. Force applied on the incus is calculated based on Hooke's Law from post-trial computer-vision analysis of recorded video following experimental determination of the spring constant of the modeled incus.

RESULTS

The described model was manufactured with a total cost of $56.50. The spring constant was experimentally determined to be 97.0 mN mm/deg, resulting in an ability to detect force applied to the modeled incus across a range of 1.2 to 5200 mN.

CONCLUSIONS

We have created a low-cost middle-ear training model with measurable objective performance outcomes. The range of detectable force exceeds expected values for the task.Level of Evidence: IV.

Anatomy Terminology Performance is Improved by Combining Jigsaws, Retrieval Practice, and Cumulative Quizzing

Science courses containing English-language terminology are a common implement in "English as a foreign language" (EFL) countries across the globe. In many of these countries, licensing examinations place added significance on terminology competence by requiring health science graduates to demonstrate mastery of English-language anatomy terms. In recent years, a wealth of research has shown active learning can offer many benefits over lecture-based, didactic approaches. Despite this work, very little has been done to test the potential of active learning in improving medical terminology performance. The present study explores this potential in two human gross anatomy lecture courses in South Korea, collecting performance and survey data from 399 undergraduates over a period of four years. Jigsaws, retrieval practice, and regular cumulative quizzing were used to mitigate three learning challenges specific to the study context: high vocabulary volume, low feelings of control over learning, and difficulties with exam preparation. The results show the reforms significantly improved both performance and learning attitudes, with students overwhelmingly favoring the use of new methods over lecture when taught using a mixture of both. Given that science learning often resembles the process of learning a foreign language, this study offers broad potential for improving terminology competence across disciplines, even for non-EFL students.

Teaching middle ear anatomy using a novel three-dimensional papercraft model

BACKGROUND

The middle ear is a complex anatomical space which is difficult to interpret from two-dimensional imagery. Appropriate surgical knowledge of the area is required to operate, yet current anatomical teaching methods are costly and hard to access for the trainee.

METHODS

A papercraft 3D design involving anatomical elements added separately to a model was designed, and then peer-validated by medical students and junior doctors. Preliminary quantitative assessment was performed using an anatomical labelling questionnaire, with six students given a lecture to act as a control. Qualitative feedback was also gathered.

RESULTS

18 participants were recruited for the study. A total of 12 models were constructed by 6 medical students and 6 junior doctors. 6 medical students received a lecture only. Qualitative feedback was positive and suggested the model improved knowledge and was useful, yet timing and complexity were issues. Students scored, on average, 37% higher after completing the model, with junior doctors also improving anatomical knowledge, though these differences were not significant (p > 0.05).

CONCLUSIONS

In this initial investigation, the model was shown to be an engaging way to learn anatomy, with the tactile and active nature of the process cited as benefits. Construction of the model improved anatomical knowledge to a greater extent than a classical lecture in this study, though this difference was not significant. Further design iterations are required to improve practical utility in the teaching environment, as well as a larger study.

[Multimodal training concept for temporal bone surgery]

BACKGROUND

Surgical training is increasingly supported by the use of simulators. For temporal bone surgery, shown here by means of mastoidectomy, there are other training models besides cadaver specimens, such as artificial temporal bones or computer-based simulators.

OBJECTIVES

A structured training concept was created which integrates different training methods of mastoidectomy with regard to effectiveness and current learning theory in education.

METHOD

A selective literature research was conducted to compare learning-theoretical findings and the availability and effectiveness of currently existing training models.

RESULTS

To acquire surgical skills, a stepwise approach is suggested. Depending on the progress with computer-based simulation, plastic or native temporal bones should be used. To achieve a plateau of the learning curve, approximately 25 semi-autonomous preparations are recommended. Different 'Objective Structured Assessments of Technical Skills' (OSATS) are implemented to assess the learning progress at different levels.

DISCUSSION

Simulation-based training is recommended until an adequate learning curve plateau is achieved. This is reasonable for patient safety, based on limited accessibility of human cadaveric temporal bones but also by findings of the learning theory.

CONCLUSION

The curriculum integrates different training models of mastoidectomy and OSATS into an overall concept. The training plan has to be continuously adapted to new findings and technical developments.

Cochlear implant surgery: Learning curve in virtual reality simulation training and transfer of skills to a 3D-printed temporal bone - A prospective trial

OBJECTIVE

Mastering Cochlear Implant (CI) surgery requires repeated practice, preferably initiated in a safe - i.e. simulated - environment. Mastoidectomy Virtual Reality (VR) simulation-based training (SBT) is effective, but SBT of CI surgery largely uninvestigated. The learning curve is imperative for understanding surgical skills acquisition and developing competency-based training. Here, we explore learning curves in VR SBT of CI surgery and transfer of skills to a 3D-printed model.

METHODS

Prospective, single-arm trial. Twenty-four novice medical students completed a pre-training CI inserting test on a commercially available pre-drilled 3D-printed temporal bone. A training program of 18 VR simulation CI procedures was completed in the Visual Ear Simulator over four sessions. Finally, a post-training test similar to the pre-training test was completed. Two blinded experts rated performances using the validated Cochlear Implant Surgery Assessment Tool (CISAT). Performance scores were analyzed using linear mixed models.

RESULTS

Learning curves were highly individual with primary performance improvement initially, and small but steady improvements throughout the 18 procedures. CI VR simulation performance improved 33% (p < 0.001). Insertion performance on a 3D-printed temporal bone improved 21% (p < 0.001), demonstrating skills transfer.

DISCUSSION

VR SBT of CI surgery improves novices' performance. It is useful for introducing the procedure and acquiring basic skills. CI surgery training should pivot on objective performance assessment for reaching pre-defined competency before cadaver - or real-life surgery. Simulation-based training provides a structured and safe learning environment for initial training.

CONCLUSION

CI surgery skills improve from VR SBT, which can be used to learn the fundamentals of CI surgery.

A quick method to expose the structures and relations of the middle ear and inner ear by cadaveric dissection

INTRODUCTION

The temporal bone contains structures related to hearing and balance, and is a valuable learning resource for medical students and trainee surgeons. The middle ear and inner ear are difficult to demonstrate by cadaveric dissection as the structures are closely contained in a small space in the dense temporal bone. Consequently, the teaching and learning of the ear are largely relegated to virtual and theoretical images, and models, which has resulted in a knowledge gap in medical students and prospective surgeons. The present study aimed to elucidate a technique that exposes the structures and relations of the middle and inner ear by cadaveric dissection.

MATERIALS AND METHODS

Forty-seven adult formalin-fixed cadaveric specimens were dissected by the proposed technique. The method was evaluated based on the extent of the structures exposed and time taken for dissection.

RESULTS

The method exposed all the contents and relations of the middle and inner ear, including the course of the facial nerve in the petrous temporal bone, in a few minutes, without use of specialized instruments like saw, drill, endoscope, operating microscope or electric trephine.

CONCLUSION

This dissection method combines maximal exposure of the structures and relations of the middle and inner ear with a short dissection time, sans use of specialized tools. It can be incorporated in the gross anatomy curriculum for medical studentsdue to the short dissection time and completeness of structures exposed. The prosected specimen can also be plastinated for use as a teaching-learning resource for medical students and surgeons.

3D-Printed Models for Temporal Bone Surgical Training: A Systematic Review

OBJECTIVE

3D-printed models hold great potential for temporal bone surgical training as a supplement to cadaveric dissection. Nevertheless, critical knowledge on manufacturing remains scattered, and little is known about whether use of these models improves surgical performance. This systematic review aims to explore (1) methods used for manufacturing and (2) how educational evidence supports using 3D-printed temporal bone models.

DATA SOURCES

PubMed, Embase, the Cochrane Library, and Web of Science.

REVIEW METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, relevant studies were identified and data on manufacturing and validation and/or training extracted by 2 reviewers. Quality assessment was performed using the Medical Education Research Study Quality Instrument tool; educational outcomes were determined according to Kirkpatrick's model.

RESULTS

The search yielded 595 studies; 36 studies were found eligible and included for analysis. The described 3D-printed models were based on computed tomography scans from patients or cadavers. Processing included manual segmentation of key structures such as the facial nerve; postprocessing, for example, consisted of removal of print material inside the model. Overall, educational quality was low, and most studies evaluated their models using only expert and/or trainee opinion (ie, Kirkpatrick level 1). Most studies reported positive attitudes toward the models and their potential for training.

CONCLUSION

Manufacturing and use of 3D-printed temporal bones for surgical training are widely reported in the literature. However, evidence to support their use and knowledge about both manufacturing and the effects on subsequent surgical performance are currently lacking. Therefore, stronger educational evidence and manufacturing knowhow are needed for widespread implementation of 3D-printed temporal bones in surgical curricula.

A time-sensitive rubric for assessing mastoidectomy proficiency

OBJECTIVE

To develop a time-sensitive, standardized rubric for cadaveric temporal bone dissection for otolaryngology resident education.

METHODS

This is a five-year prospective cohort study that evaluated otolaryngology resident performance during sequential cadaveric temporal bone dissection courses at a single otolaryngology residency training program. A canal-wall-up mastoidectomy with a facial recess approach was performed adhering to a 30-minute time limit and graded according to a standardized rubric. Main outcome measures included: (1) correct structure identification and (2) injuries sustained to structures as compared by resident post-graduate year (PGY) level.

RESULTS

Thirteen residents were evaluated from October 2012 to March 2017. This included 57 individual graded exercises performed over ten dissection courses. The average score for PGY-2 residents was lowest (68.9), and PGY-5 residents achieved the highest average score (87.7). Junior residents correctly identified fewer structures (77.5%) when compared to senior residents (91.3%), p < 0.0001. Correct performance of a facial recess approach was achieved by 100% of senior residents, but only 59.3% of junior residents (p = 0.0003). The percentage of major injuries, which included the facial nerve, tegmen, labyrinth, and ossicular chain, decreased each PGY-level from a maximum of 17% by PGY-2 residents to a minimum of 5% by PGY-5 residents.

CONCLUSION

Senior residents correctly identify more structures and are able to complete a facial recess approach with higher fidelity when subjected to a time-sensitive graded mastoidectomy rubric.

The Impact of Virtual Reality Training on the Quality of Real Antromastoidectomy Performance

BACKGROUND

The aim of this paper is to analyze the results of virtual reality (VR) antromastoidectomy simulation training and the transferability of the obtained skills to real temporal bone surgery.

METHODS

The study was conducted prospectively on a group of 10 physicians, and was composed of five VR simulation training sessions followed by live temporal bone surgery. The quality of performance was evaluated with a Task-Based Checklist (TBC) prepared by John Hopkins Hospital. Additionally, during every VR session, the number and type of mistakes (complications) were noted.

RESULTS

The quality of performance measured by the TBC increased significantly during consecutive VR sessions. The mean scores for the first and fifth sessions were 1.84 and 4.27, respectively (p < 0.001). Furthermore, the number of mistakes in consecutive VR sessions was gradually reduced from 11 to 0. During supervised surgery, all the participants were able to perform at least part of an antromastoidectomy, and the mean TBC score was 3.57. There was a significant strong positive correlation between the individual results of the fifth VR session and the individual results of supervised surgery in the operating room (r_p = 0.89, p = 0.001).

CONCLUSIONS

Virtual reality for temporal bone training makes it possible to acquire surgical skills in a safe environment before performing supervised surgery. Furthermore, the individual final score of virtual antromastoidectomy training allows a prediction of the quality of performance in real surgery.

Tumor phantom for training and research in transoral surgery

OBJECTIVE

With the paradigm shift towards minimally invasive surgical techniques such as transoral laser microsurgery and transoral robotic surgery for resection of head and neck malignancies, there is a need to enhance the surgical training of these techniques as well as provide a platform for testing new approaches and technologies. The steeper learning curve associated with minimally invasive surgical techniques may be mitigated with the use of tumor phantoms (TP) placed in cadaver models.

METHODS

An injectable TP was developed using an agar-gelatin base, unsalted chicken stock, deionized water, food coloring for visual mimicry, and iohexol for radiographic mimicry. Four percentage glutaraldehyde was used as a cross-linking agent for solidification of the TP. The TP was then injected in various mucosal anatomic sites in four unfixed cadaver heads. Visual, radiographic, and tactile mimicry was assessed via endoscopy, CT scan, and tumor dissection and palpation, respectively.

RESULTS

Tumor phantom injection was successfully achieved in all four cadaver heads. Visually and tactilely, the TP demonstrated similar color change, induration, and firmness of a typical squamous cell carcinoma (SCCa). However, ulceration that is often seen with SCCa could not be replicated. CT mimicry was compared with nine patients with known SCCa. Tumor radiodensity in the nine patients was between 77 and 110 HU (mean 86.3 HU) whereas TP radiodensity was 59 and 127 HU (mean 93.7 HU), with no significant difference between groups (P = .21).

CONCLUSION

This inexpensive, easy to apply, and unique tumor phantom could be used both to train transoral techniques and as a tool to further investigate new approaches and technologies for transoral surgery.

LEVEL OF EVIDENCE

NA.

Reprint of Corrosion casting of the temporal bone: Review of the technique

The temporal bone has the most sophisticated anatomy of the whole skeleton. Its study is a challenge for students and surgeons. An inverse model of the visually obscured cavities and canals can facilitate better three-dimensional orientation and investigation. This can be made by means of corrosion casting, which is an established technique first documented on the temporal bone at the beginning of the nineteenth century. The prepared specimens are suitable not only for teaching purposes but also for research on the fascinating topography of the osseous labyrinth and the whole temporal bone. Many important studies on temporal bone anatomy are based on this technique. An extensive review of the pertinent literature is provided in relation to each method available.

Construct Validation of a Printed Bone Substitute in Otologic Education

: Patient safety demands enhancements in training. Graduated cadaveric bone exposure is fundamental to otologic training. Printed bone models (PBM) provide a low-cost, anatomically consistent adjunct to cadaveric materials in trainee skill acquisition.The purpose of this study is to determine if resident training level can be distinguished on the basis of performance employing a printed temporal bone model, graded by a previous validated scale.

METHODS

Nineteen residents (11 male, 8 female) from 9 graduate programs, attending a National Otolaryngology Conference, completed a mastoidectomy with posterior tympanotomy on identic 3D PBMs and a Likert scale (1-7) survey on subjective appreciation of the simulation. Four experts graded participant performance using the previously validated Welling Scale.

RESULTS

ANOVA revealed significant performance differences between the junior/intermediate and junior/senior PGY cohorts. No difference was observed between intermediate/senior cohorts on the basis of PGY or subjective temporal bone dissection experience. Clustering aspects of the scale with specific focus on thinning tasks found a similar outcome to the composite scale scores.Subjective experience judged printed bone to be similar to cadaveric in drill-bone interaction. Participants believed the simulation would improve surgical performance, comfort with actual patients, and operative speed.

CONCLUSION

Subjectively, printed bone compared favorably to cadaveric.The simulation demonstrated construct validity but was challenged in differentiating senior from intermediate trainee performance. This may be a function of the PBM inherent character, limitations in grading instrument fidelity or sample size. It is also possible that the dominant period of skill acquisition for mastoidectomy and posterior tympanotomy are primarily acquired during the junior training.

3D printed temporal bone as a tool for otologic surgery simulation

PURPOSE

In this face validity study, we discuss the fabrication and utility of an affordable, computed tomography (CT)-based, anatomy-accurate, 3-dimensional (3D) printed temporal bone models for junior otolaryngology resident training.

MATERIALS AND METHODS

After IRB exemption, patient CT scans were anonymized and downloaded as Digital Imaging and Communications in Medicine (DICOM) files to prepare for conversion. These files were converted to stereolithography format for 3D printing. Important soft tissue structures were identified and labeled to be printed in a separate color than bone. Models were printed using a desktop 3D printer (Ultimaker 3 Extended, Ultimaker BV, Netherlands) and polylactic acid (PLA) filament. 10 junior residents with no previous drilling experience participated in the study. Each resident was asked to drill a simple mastoidectomy on both a cadaveric and 3D printed temporal bone. Following their experience, they were asked to complete a Likert questionnaire.

RESULTS

The final result was an anatomically accurate (XYZ accuracy = 12.5, 12.5, 5 μm) 3D model of a temporal bone that was deemed to be appropriate in tactile feedback using the surgical drill. The total cost of the material required to fabricate the model was approximately $1.50. Participants found the 3D models overall to be similar to cadaveric temporal bones, particularly in overall value and safety.

CONCLUSIONS

3D printed temporal bone models can be used as an affordable and inexhaustible alternative, or supplement, to traditional cadaveric surgical simulation.

Creating a Validated Simulation Training Curriculum in Otolaryngology

Purpose of Review

Simulation-based training is an integral component of surgical training. It allows practice of technical skills within a safe environment without compromising patient safety. This article seeks to review current virtual and non-virtual reality simulation models within the literature and review their validation status.

Recent Findings

Many simulation models exist within otolaryngology and are currently being used for education. New models are also continuously being developed; however, validity should be proven for the models before incorporating their use for educational purposes. Validity should be determined by experts and trainees themselves.

Summary

A validated simulation curriculum should be incorporated within the otolaryngology training programme. A curriculum based on the current training programme at our institution serves as an exemplar for local adoption.

Ultra-high-fidelity virtual reality mastoidectomy simulation training: a randomized, controlled trial

PURPOSE

Ultra-high-fidelity (UHF) graphics in virtual reality (VR) simulation might improve surgical skill acquisition in temporal bone training. This study aims to compare UHF VR simulation training with conventional, screen-based VR simulation training (cVR) with respect to performance and cognitive load (CL).

METHODS

In a randomized trial with a cross-over design, 24 students completed a total of four mastoidectomies in a VR temporal bone surgical simulator: two performances under UHF conditions using a digital microscope and two performances under conventional conditions using screen-based VR simulation. Performances were assessed by two blinded raters using an established assessment tool. In addition, CL was estimated as the relative change in secondary-task reaction time during simulation when compared with individual baseline measurements. Data were analyzed using linear mixed model analysis for repeated measurements.

RESULTS

The mean final-product performance score was significantly lower in UHF VR simulation compared to cVR simulation [mean difference 1.0 points out of 17 points, 95% CI (0.2-1.7), p = 0.02]. The most important factor for performance during UHF simulation was the ability to achieve stereovision (mean difference = 3.4 points, p < 0.001). Under the UHF VR condition, CL was significantly higher than during cVR (28% vs. 18%, respectively, p < 0.001).

CONCLUSION

UHF graphics in VR simulation training reduced performance and induced a higher CL in novices than conventional, screen-based VR simulation training. Consequently, UHF VR simulation training should be preceded by cVR training and might be better suited for the training of intermediates or experienced surgeons.

Corrosion casting of the temporal bone: Review of the technique

The temporal bone has the most sophisticated anatomy of the whole skeleton. Its study is a challenge for students and surgeons. An inverse model of the visually obscured cavities and canals can facilitate better three-dimensional orientation and investigation. This can be made by means of corrosion casting, which is an established technique first documented on the temporal bone at the beginning of the nineteenth century. The prepared specimens are suitable not only for teaching purposes but also for research on the fascinating topography of the osseous labyrinth and the whole temporal bone. Many important studies on temporal bone anatomy are based on this technique. An extensive review of the pertinent literature is provided in relation to each method available.

Assessment of Middle Ear Anatomy Teaching Methodologies Using Microscopy versus Endoscopy: A Randomized Comparative Study

Teaching methodologies for the anatomy of the middle ear have not been investigated greatly due to the middle ear's highly complex structure and hidden location inside of the temporal bone. The aim of this randomized study was to quantitatively compare the suitability of using microscope- and endoscope-based methods for teaching the anatomy of the middle ear. We hypothesize that the endoscopic approach will be more efficient compared to the microscopic approach. To answer the study questions, 33 sixth-year medical students, residents and otorhinolaryngology specialists were randomized either into the endoscopy or the microscopy group. Their anatomical knowledge was assessed using a structured anatomical knowledge test before and after each session. Each participant received tutoring on a human cadaveric specimen using one of the two methods. They then performed a hands-on dissection. After 2-4 weeks, the same educational curriculum was repeated using the other technique. The mean gains in anatomical knowledge for the specialists, residents, and medical students were +19.0%, +34.6%, and +23.4%, respectively. Multivariate analyses identified a statistically significant increase in performance for the endoscopic method compared to the microscopic technique (P < 0.001). For the recall of anatomical structures during dissection, the endoscopic method outperformed the microscopic technique independently of the randomization or the prior training level of the attendees (P < 0.001). In conclusion, the endoscopic approach to middle ear anatomy education is associated to an improved gain in knowledge as compared to the microscopic approach. The participants subjectively preferred the endoscope for educational purposes.

Applied Force during Piston Prosthesis Placement in a 3D-Printed Model: Freehand vs Robot-Assisted Techniques

OBJECTIVES

To describe a 3D-printed middle ear model that quantifies the force applied to the modeled incus. To compare the forces applied during placement and crimping of a stapes prosthesis between the Robotic ENT Microsurgery System ( REMS) and the freehand technique in this model.

STUDY DESIGN

Prospective feasibility study.

SETTING

Robotics laboratory.

SUBJECTS AND METHODS

A middle ear model was designed and 3D printed to facilitate placement and crimping of a piston prosthesis. The modeled incus was mounted to a 6-degree of freedom force sensor to measure forces/torques applied on the incus. Six participants-1 fellowship-trained neurotologist, 2 neurotology fellows, and 3 otolaryngology-head and neck surgery residents-placed and crimped a piston prosthesis in this model, 3 times freehand and 3 times REMS assisted. Maximum force applied to the incus was then calculated for prosthesis placement and crimping from force/torque sensor readings for each trial. Robotic and freehand outcomes were compared with a linear regression model.

RESULTS

Mean maximum magnitude of force during prosthesis placement was 126.4 ± 73.6 mN and 105.0 ± 69.4 mN for the freehand and robotic techniques, respectively ( P = .404). For prosthesis crimping, the mean maximum magnitude of force was 469.3 ± 225.2 mN for the freehand technique and 272.7 ± 97.4 mN for the robotic technique ( P = .049).

CONCLUSIONS

Preliminary data demonstrate that REMS-assisted stapes prosthesis placement and crimping are feasible with a significant reduction in maximum force applied to the incus during crimping with the REMS in comparison with freehand.

Do experts practice what they profess?

We investigated the variation of drilled regions of expert and trainee surgeons performing virtual temporal bone surgery to identify their compliance with standard drilling procedures. To this end, we recruited seven expert and six trainee ENT surgeons, who were asked to perform the surgical preparations for cochlear implantation on a virtual temporal bone. The temporal bone was divided into six regions using a semi-automated approach. The drilled area in each region was compared between groups using a sign test. Similarity within groups was calculated as a ratio of voxels (3D points) drilled by at least 75% of surgeons and at least 25% of surgeons. We observed a significant difference between groups when performing critical tasks such as exposing the facial nerve, opening the facial recess, and finding the round window. In these regions, experts’ practice is more similar to each other than that between trainees. Consistent with models of skills development, expertise and expert-performance, the outcome of the analysis shows that experts perform similarly in critical parts of the procedure, and do indeed practice what they profess.

European status on temporal bone training: a questionnaire study

PURPOSE

In otorhinolaryngology training, introduction to temporal bone surgery through hands-on practice on cadaveric human temporal bones is the gold-standard training method before commencing supervised surgery. During the recent decades, the availability of such specimens and the necessary laboratory facilities for training seems to be decreasing. Alternatives to traditional training can consist of drilling artificial models made of plaster or plastic but also virtual reality (VR) simulation. Nevertheless, the integration and availability of these alternatives into specialist training programs remain unknown.

METHODS

We conducted a questionnaire study mapping current status on temporal bone training and included responses from 113 departments from 23 countries throughout Europe.

RESULTS

In general, temporal bone training during residency in ORL is organized as in-house training, or as participation in national or international temporal bone courses or some combination hereof. There are considerable differences in the availability of training facilities for temporal bone surgery and the number of drillings each ORL trainee can perform. Cadaveric dissection is still the most commonly used training modality.

CONCLUSIONS

VR simulation and artificial models are reported to be used at many leading training departments already. Decreasing availability of cadavers, lower costs of VR simulation and artificial models, in addition to established evidence for a positive effect on the trainees' competency, were reported as the main reasons. Most remaining departments expect to implement VR simulation and artificial models for temporal bone training into their residency programs in the near future.

Time-saving and fail-safe dissection method for vestibulocochlear organs in gross anatomy classes

Because the vestibulocochlear organs are tiny and complex, and are covered by the petrous part of the temporal bone, they are very difficult for medical students to dissect and visualize during gross anatomy classes. Here, we report a time-saving and fail-safe procedure we have devised, using a hand-held hobby router. Nine en bloc temporal bone samples from donated human cadavers were used as trial materials for devising an appropriate procedure for dissecting the vestibulocochlear organs. A hand-held hobby router was used to cut through the temporal bone. After trials, the most time-saving and fail-safe method was selected. The performance of the selected method was assessed by a survey of 242 sides of 121 cadavers during gross anatomy classes for vestibulocochlear dissection. The assessment was based on the observation ratio. The best procedure appeared to be removal of the external acoustic meatus roof and tympanic cavity roof together with removal of the internal acoustic meatus roof. The whole procedure was completed within two dissection classes, each lasting 4.5 hr. The ratio of surveillance for the chorda tympani and three semicircular canals by students was significantly improved during 2013 through 2016. In our dissection class, "removal of the external acoustic meatus roof and tympanic cavity roof together with removal of the internal acoustic meatus roof" was the best procedure for students in the limited time available. Clin. Anat. 30:703-710, 2017. © 2017Wiley Periodicals, Inc.

Establishing a Temporal Bone Laboratory in Teaching Institutes to Train Future Otorhinolaryngologists and Fundamentals of Temporal Bone Laboratory: Considerations and Requirements

Temporal bone dissection has important role in educating, and training the surgeons. Temporal bone has complicated three dimensional anatomy and it is challenging for young surgeons to understand and operate. Not knowing the anatomy may cause serious consequences to patient due to injury to vital structures. It is important to learn temporal bone harvesting techniques, preservation of specimens, fixation and to reduce the health hazards posed by these specimens by taking safety measures. Spending more time in temporal bone laboratory and repeated dissection of temporal bones provides the skills necessary in the operating room for future generation. All training institutes should establish temporal bone laboratory in their department to provide the necessary expertise to future generation while maintaining safe and secure environment.

3D-printed pediatric endoscopic ear surgery simulator for surgical training

INTRODUCTION

Surgical simulators are designed to improve operative skills and patient safety. Transcanal Endoscopic Ear Surgery (TEES) is a relatively new surgical approach with a slow learning curve due to one-handed dissection. A reusable and customizable 3-dimensional (3D)-printed endoscopic ear surgery simulator may facilitate the development of surgical skills with high fidelity and low cost. Herein, we aim to design, fabricate, and test a low-cost and reusable 3D-printed TEES simulator.

METHODS

The TEES simulator was designed in computer-aided design (CAD) software using anatomic measurements taken from anthropometric studies. Cross sections from external auditory canal samples were traced as vectors and serially combined into a mesh construct. A modified tympanic cavity with a modular testing platform for simulator tasks was incorporated. Components were fabricated using calcium sulfate hemihydrate powder and multiple colored infiltrants via a commercial inkjet 3D-printing service.

RESULTS

All components of a left-sided ear were printed to scale. Six right-handed trainees completed three trials each. Mean trial time (n = 3) ranged from 23.03 to 62.77 s using the dominant hand for all dissection. Statistically significant differences between first and last completion time with the dominant hand (p < 0.05) and average completion time for junior and senior residents (p < 0.05) suggest construct validity.

CONCLUSIONS

A 3D-printed simulator is feasible for TEES simulation. Otolaryngology training programs with access to a 3D printer may readily fabricate a TEES simulator, resulting in inexpensive yet high-fidelity surgical simulation.

Mental practice in postgraduate training: a randomized controlled trial in mastoidectomy skills

Background

Mental practice, the cognitive rehearsal of a task in the absence of overt physical movement, has been successfully used in teaching complex psychomotor tasks including sports and music, and recently, surgical skills.

The objectives of this study were, 1) To develop and evaluate a mental practice protocol for mastoidectomy 2) To assess the immediate impact of mental practice on a mastoidectomy surgical task among senior Otolaryngology─Head & Neck Surgery (OHNS) residents.

Method

Three expert surgeons were interviewed using verbal protocol analysis to develop a mastoidectomy mental practice script. Twelve senior Residents from Canadian training programs were randomized into two groups. All Residents were video-recorded performing a baseline mastoidectomy in a temporal bone lab. The intervention group received mental practice training, while the control group undertook self-directed textbook study. All subjects were then video-recorded performing a second mastoidectomy. Changes in pre- and post-test scores using validated expert ratings, the Task Specific Evaluation of Mastoidectomy and the Global Evaluation of Mastoidectomy, were statistically analyzed.

Results

A mental practice script was successfully developed based on interviews of three expert surgeon-educators. Task Specific Evaluation and Global Evaluation scores increased in both the mental practice and textbook study groups; there was no significant difference between the two groups in the change in scores post-intervention. There was a high and statistically signficant correlation between evaluators on the outcome measures.

Conclusions

We were not able to demonstrate a significant difference for the benefits of mental practice in mastoidectomy, possibly due to the sample size. However, mental practice is a surgical education tool which is portable, accessible, inexpensive and safe.

Electronic supplementary material

The online version of this article (doi:10.1186/s40463-016-0162-2) contains supplementary material, which is available to authorized users.

Papercraft temporal bone in the first step of anatomy education

OBJECTIVE

(1) To compare temporal bone anatomy comprehension taught to speech therapy students with or without a papercraft model. (2) To explore the effect of papercraft simulation on the understanding of surgical approaches in first-year residents.

METHODS

(1) One-hundred and ten speech therapy students were divided into three classes. The first class was taught with a lecture only. The students in the second class were given a lecture and a papercraft modeling task without instruction. The third class modeled a papercraft with instruction after the lecture. The students were tested on their understanding of temporal bone anatomy. (2) A questionnaire on the understanding of surgical approaches was completed by 10 residents before and after the papercraft modeling. The papercraft models were cut with scissors to simulate surgical approaches.

RESULTS

(1) The average scores were 4.4/8 for the first class, 4.3/8 for the second class, and 6.3/8 for the third class. The third class had significantly better results than the other classes (p<0.01, Kruskal-Wallis test). (2) The average scores before and after the papercraft modeling and cutting were 2.6/7 and 4.9/7, respectively. The numerical rating scale score significantly improved (p<0.01, Wilcoxon signed-rank test).

CONCLUSION

The instruction of the anatomy using a papercraft temporal bone model is effective in the first step of learning temporal bone anatomy and surgical approaches.