Otologic Skills Training

3D-printed temporal bone models for training: Does material transparency matter?

PURPOSE

To investigate the impact of 3D-printed temporal bone models with two different material transparencies on trainees' mastoidectomy performance.

METHODS

Eleven ORL residents performed two anatomical mastoidectomies with posterior tympanotomy on two 3D-printed models with different transparency and VR simulation training. Participants where divided into two groups based on their experience. Within each group participants were randomized to start with the model printed in a completely opaque material or in a material featuring some degree of transparency. After drilling on 3D-printed models, the participants performed two similar mastoidectomies on human cadavers: one on the left side of one cadaver and one on the right side of another cadaver. After drilling 3D-printed models and cadavers, the final-product performances were evaluated by two experienced raters using the 26-item modified Welling Scale. Participants also evaluated the models using a questionnaire.

RESULTS

Overall, the participants performed 25 % better on the 3D-printed models featuring transparency compared to the opaque models (18.6 points vs 14.9 points, mean difference = 3.7, 95 % CI 2.0-5.3, P < 0.001)). This difference in performance was independent of which material the participants had drilled first. In addition, the residents also subjectively rated the transparent model to be closer to cadaver dissection. The experienced group starting with the 3D-printed models scored 21.5 points (95 % CI 20.0-23.1), while the group starting with VR simulation training score 18.4 points (95 % CI 16.6-20.3).

CONCLUSION

We propose that material used for 3D-printing temporal bone models should feature some degree of transparency, like natural bone, for trainees to learn and exploit key visual cues during drilling.

Deep Learning Method for Rapid Simultaneous Multistructure Temporal Bone Segmentation

OBJECTIVE

To develop and validate a deep learning algorithm for the automated segmentation of key temporal bone structures from clinical computed tomography (CT) data sets.

STUDY DESIGN

Cross-sectional study.

SETTING

A total of 325 CT scans from a clinical database.

METHOD

A state-of-the-art deep learning (DL) algorithm (SwinUNETR) was used to train a prediction model for rapid segmentation of 9 key temporal bone structures in a data set of 325 clinical CTs. The data set was manually annotated by a specialist to serve as the ground truth. The data set was randomly split into training (n = 260) and testing (n = 65) sets. The model's performance was objectively assessed through external validation on the test set using metrics including Dice, Balanced accuracy, Hausdorff distances, and processing time.

RESULTS

The model achieved an average Dice coefficient of 0.87 for all structures, an average balanced accuracy of 0.94, an average Hausdorff distance of 0.79 mm, and an average processing time of 9.1 seconds per CT.

CONCLUSION

The present DL model for the automated simultaneous segmentation of multiple structures within the temporal bone from CTs achieved high accuracy according to currently commonly employed objective analysis. The results demonstrate the potential of the method to improve preoperative evaluation and intraoperative guidance in otologic surgery.

Content Validity of a High-Fidelity Surgical Middle Ear Simulator: A Randomized Prospective International Multicenter Trial

OBJECTIVE

After demonstration of face validity of a surgical middle ear simulator (SMS) previously, we assessed the content validity of the simulator with otolaryngology residents.

STUDY DESIGN

Multicenter randomized prospective international study.

SETTING

Four academic institutions.

METHODS

Novice participants were randomized into control, low-fidelity (LF), and high-fidelity (HF) groups. Control and LF produced 2 recordings from 2 attempts, and HF produced 4 recordings from 10 attempts, with trials 1, 4, 7, and 10 used for scoring. Three blinded experts graded videos of the simulated stapedectomy operation using an objective skills assessment test format consisting of global and stapedotomy-specific scales.

RESULTS

A total of 152 recordings from 61 participants were included. Baseline characteristics did not differ significantly between groups. Depending on the step of the operation, inter-rater reliability ranged from 24 to 90%. For LF and HF, years of training was significantly associated with improved scores in certain objective skills assessment test subparts. HF outperformed the control group on stapes and global scores ( p < 0.05). The HF group demonstrated improvement in global score over trials, but plateaued after four trials. Scores varied greatly for participants from different institutions in certain operative steps, such as transecting incudostapedial joints, likely due to differences in instrumentation and time elapsed since manufacture.

CONCLUSION

Practice with SMS led to better performance in both global and stapes-specific scores. Further studies are needed to examine construct validity and to create otology-appropriate grading systems. Variables like instrumentation and decline in flexibility of the simulator after 12 months greatly affect performance on the simulator.

Developing a virtual reality (VR) application for practicing the ABCDE approach for systematic clinical observation

BACKGROUND

The Airways, Breathing, Circulation, Disability, Exposure (ABCDE) approach is an international approach for systematic clinical observation. It is an essential clinical skill for medical and healthcare professionals and should be practiced repeatedly. One way to do so is by using virtual reality (VR). The aim was therefore to develop a VR application to be used by inexperienced health students and professionals for self-instructed practice of systematic clinical observation using the ABCDE approach.

METHODS

An iterative human-centred approach done in three overlapping phases; deciding on the ABCDE approach, specifying the requirements, and developing the application.

RESULTS

A total of 138 persons were involved. Eight clinical observations were included in the ABCDE approach. The requirements included making it possible for inexperienced users to do self-instructed practice, a high level of immersion, and a sense of presence including mirroring the physical activities needed to do the ABCDE approach, allowing for both single and multiplayer, and automatic feedback with encouragement to repeat the training. In addition to many refinements, the testing led to the development of some new solutions. Prominent among them was to get players to understand how to use the VR hand controllers and start to interact with the VR environment and more instructions like showing videos on how to do observations. The solutions in the developed version were categorised into 15 core features like onboarding, instructions, quiz, and feedback.

CONCLUSION

A virtual reality application for self-instructed practice of systematic clinical observation using the ABCDE approach can be developed with sufficient testing by inexperienced health students and professionals.

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.

Veress needle insertion simulation model: A simple new module for advanced surgical skill training

Introduction

Training on Veress needle (VN) insertion cannot be done by observation without practicing tactile feedback. In this study, a simple and reproducible VN insertion training model was created. The aim of this study was to evaluate the validity of using the proposed model in simulating actual real-life surgical experiences.

Methods

The proposed VN insertion training model is made of three layers of synthetic rubber and plastic materials, simulating the tensile strength and texture of the three abdominal wall muscle layers. Surgeons and senior residents with experience in minimally invasive procedures were asked to practice VN insertion on this model, each completing the procedure three times. Participants were then asked to record their comments and answer six questions regarding their experience practicing on the model.

Results

Ten surgeons and four senior residents participated in this study. All participants agreed or strongly agreed that the model simulates the surgery experience regarding the shape and overall structure, tactile feedback and confirmation of complete/successful insertion. Twelve participants (86%) agreed or strongly agreed that the pressure/force needed for VN insertion was like real surgery experience and that the overall experience with using this model is similar to the real surgical experience. Almost all participants (93%) agreed or strongly agreed that the model is a valuable resource for training before practicing the procedure on real patients.

Conclusions

The VN insertion training model provides a valuable training opportunity on a demanding surgical skill. It is simple, reproducible and closely simulates surgery.

Cochlear implantation: Exploring the effects of 3D stereovision in a digital microscope for virtual reality simulation training - A randomized controlled trial

In cochlear implantation (CI), excellent surgical technique is critical for hearing outcomes. Recent advances in temporal bone Virtual Reality (VR) training allow for specific training of CI and through introduction of new digital microscopes with ultra-high-fidelity (UHF) graphics. This study aims to investigate whether UHF increases performance in VR simulation training of CI electrode insertion compared with conventional, screen-based VR (cVR).

METHODS

Twenty-four medical students completed a randomized, controlled trial of an educational intervention. They performed a total of eight CI electrode insertions each in blocks of four using either UHF-VR or cVR, in randomized order. CI electrode insertion performances were rated by two blinded expert raters using a structured assessment tool supported by validity evidence.

RESULTS

Performance scores in cVR were higher than in the UHF-VR simulation although this was not significant (19.8 points, 95% CI [19.3-20.3] vs. 18.8 points, 95% CI [18.2-19.4]; P = 0.09). The decisive factor for performance was participants' ability to achieve stereovision (mean difference = 1.1 points, 95% CI [0.15-2.08], P = 0.02).

DISCUSSION

No additional benefit was found from UHF-VR over cVR training of CI electrode insertion for novices. Consequently, standard cVR simulation should be used for novices' basic skills acquisition in CI surgery. Future studies should instead explore the effects of other improvements in CI surgery training and if the lacking benefit of UHF-VR also applies for more experienced learners.

CONCLUSION

The increased graphical perception and the superior lifelikeness of UHF-VR does not improve early skills acquisition of CI insertion for novices.

A novel view of computed tomography images similar to the visual field of otologic surgeons

OBJECTIVES

In preparation for endoscopic sinus surgery (ESS), the most important computed tomography (CT) image for otolaryngologists is the coronal plane image because it has a viewpoint similar to that of the surgical visual field. Contrastingly, otologic surgeons refer to axial and coronal plane images before ear surgery and must imagine the anatomical structure of the temporal bone by reconstructing three-dimensional (3D) images in their minds. We propose a "surgical position view (SPV) image," a novel viewpoint of CT images that enables otologic surgeons to see a perspective similar to the surgical visual field.

METHOD

Sagittal plane CT images of the temporal bone were created from axial plane images with multi-planar reconstruction (MPR). Then, the SPV image was obtained by rotating it 90° to the supine position. The entire process can be performed anywhere in the hospital within 1 minute using the electronic medical record computer's image viewer.

RESULTS

SPV images show anatomical structures of the temporal bone, external ear canal, mastoid cavity, sigmoid vein, facial nerve, ossicles, and cochlea, in a similar view to the actual ear surgery. Soft tissue such as cholesteatoma is depicted in the same concentration as the normal CT image.

CONCLUSION

The SPV image enables an otologic surgeon to see the temporal bone CT image from the actual ear surgery viewpoint simply and quickly. It helps to visualize the 3D anatomical structure of the temporal bone and can be useful for ear surgery planning.

LEVEL OF EVIDENCE

5.

High-Fidelity Surgical Middle Ear Simulator: A Pilot Study

OBJECTIVES

To assess a middle ear simulator as a surgical training tool among a cohort of novice trainees.

STUDY DESIGN

Prospective pilot study.

SETTING

The George Washington University Hospital (tertiary care academic hospital).

PARTICIPANTS

Twenty one medical students and physician assistant students completed the protocol. Each student produced four recordings over 10 attempts. The two raters were attending surgeons from the George Washington University Hospital.

INTERVENTIONS

Stapedotomies performed on a high-fidelity middle ear simulator. Participants were assessed at baseline with a Purdue pegboard test and trained with video and a low fidelity middle ear simulator.

MAIN OUTCOME MEASURES

Two experts rated recordings on scales based upon a validated objective skills assessment test (OSAT) format.

RESULTS

Inter-rater reliability was strong across all stapedotomy skills scores and global rating scores. Participants demonstrated statistically significant improvement up to the third recording (seventh attempt), but the scores on the fourth recording (tenth attempt) were not significantly different from the third. One participant failed to improve in score over 10 attempts. Pegboard test performance was not correlated with score improvement. Low-fidelity trial time was significantly correlated to stapedotomy and global rating scores.

CONCLUSIONS

This pilot study serves as the first investigation of this middle ear simulator amongst a cohort of trainees. A high-fidelity middle ear simulator may serve as a measurement tool to select future surgical trainees, customize training pathways, and assess surgical capacity before graduation.

Assessing competence in cochlear implant surgery using the newly developed Cochlear Implant Surgery Assessment Tool

PURPOSE

To develop and gather validity evidence for a novel tool for assessment of cochlear implant (CI) surgery, including virtual reality CI surgery training.

METHODS

Prospective study gathering validity evidence according to Messick's framework. Four experts developed the CI Surgery Assessment Tool (CISAT). A total of 35 true novices (medical students), trained novices (residents) and CI surgeons performed two CI-procedures each in the Visible Ear Simulator, which were rated by three blinded experts. Classical test theory and generalizability theory were used for reliability analysis.

RESULTS

The CISAT significantly discriminated between the three groups (p < 0.001). The generalizability coefficient was 0.76 and most of the score variance (53.3%) was attributable to the participant and only 6.8% to the raters. When exploring a standard setting for CI surgery, the contrasting groups method suggested a pass/fail score of 36.0 points (out of 55), but since the trained novices performed above this, we propose using the mean CI surgeon performance score (45.3 points).

CONCLUSION

Validity evidence for simulation-based assessment of CI performance supports the CISAT. Together with the standard setting, the CISAT might be used to monitor progress in competency-based training of CI surgery and to determine when the trainee can advance to further training.

Hybrid Surgical Simulator: A Temporal Bone Simulator Validation Study of the Stryker Surgical Simulator (S3)

INTRODUCTION

The Stryker Surgical Simulator is a hybrid, temporal bone simulator that uses both tactile and haptic feedback combined with a computer interface. We sought to validate this simulator as an otolaryngology resident training tool for performing tympanomastoidectomy.

MATERIALS AND METHODS

15 residents and staff performed five basic cortical mastoidectomies. Staff surgeons comprised the "expert" cohort and resident surgeons comprised the "trainee" cohort. Subjective evaluation of the face validity and content validity was assessed via pre- and postquestionnaires. Objective evaluation of content validity was assessed through grading of each temporal bone dissection specimen, comparing time to task completion, and calculating the rate of injury to critical structures. Study approved by the Institutional Review Board (2013.0001).

RESULTS

Post hoc questionnaires showed that both staff and residents subjectively rated the simulator favorably on face validity, content validity, and all global assessment categories, though there were no significant distinctions between groups (P > 0.05). The resident group had a significantly longer drilling time compared with the staff group throughout the series of tympanomastoidectomies (P = 0.008), and both groups showed a decrease in time to task completion with repetitive drilling. However, there were no significant differences in surgical performance as evaluated by a blinded senior neurotologist (P = 0.52). There were also no critical injuries recorded by the simulator in any of the 75 trials, preventing any evaluation on this measure.

CONCLUSIONS

Despite favorable subjective evaluations by both staff and residents, objective discrimination between experienced and novice participants was not achieved. This was likely in part due to inherent design flaws of the simulator. This emphasizes the potential shortcomings of surgical simulation models for highly technical procedures and points to the importance of intensive study and validation prior to incorporation of commercial training models into surgical training programs.

Low-fidelity otoscopy simulation and anatomy training: A randomized controlled trial

OBJECTIVES

To evaluate whether the use of low-fidelity otoscopy simulation improved medical students' theoretical knowledge of middle ear anatomy and pathologies compared to traditional teaching methods.

METHODS

This was a randomized controlled trial. Simulation workshops were conducted in April 2019 in the Lyon Sud University medical faculty, France. Students were randomly assigned to the simulation group (n=105) or to the control group (n=95). The students in the control group answered a questionnaire evaluating theoretical knowledge (25 true-false questions) before the simulation tutorial, while the students in the simulation group answered the same questions after the tutorial. Both groups also filled out a satisfaction questionnaire for feedback.

RESULTS

196 of the 200 students who participated in the study completed the knowledge assessment questionnaire. Scores were 32.0% higher in the simulation group than in the control group (mean scores, 12.0/20 vs. 9.1/20; P<0.0001). 184 of the 191 students who completed the satisfaction questionnaire (96.3%) were satisfied or very satisfied with the workshop, and all but one (99.5%) recommended keeping it in the curriculum. In the free comments fields, students highlighted the educational value of learning without the stress of patient discomfort.

CONCLUSION

Otoscopy simulation is an effective training method, improving theoretical knowledge compared with conventional theoretical training.

Real-time light-guided vocal fold injection as a simulation-based training tool

OBJECTIVE

Cricothyroid (CT) approach for vocal fold injection (VFI) has advantages of a low complication rate, suitability for in-office practice, and good patient compliance. However, it requires a high level of experience and a steep learning curve due to invisibility of needle. Recently, real-time light-guided VFI (RL-VFI) was developed for safe and precise injection into laryngeal structures under light guidance. Herein, we describe the development of a simulation-based training (SBT) program using RL-VFI for CT approach and report its preliminary application with in-training otolaryngologists.

METHODS

The workshop comprised 3 sessions: mini-lectures, and two hands-on training courses of conventional VFI and RL-VFI. Excised canine larynges and the device for RL-VFI were prepared for hands-on courses. Comfort levels for VFI was evaluated using visual analogue scale after each session. Trainees were requested to identify the needle tip on the target point lateral to vocal process. The time (s) to reach the target point was measured in all procedures. After workshop, all participants filled out questionnaires regarding their future preference for conventional VFI and RL-VFI.

RESULTS

Eleven otolaryngology residents participated in the study. The mean comfort levels were 1.7 ± 1.6, 5.5 ± 2.6, 4.8 ± 1.7, and 7.5 ± 1.6 for pre-workshop, post-lecture, post-conventional VFI, and post-RL-VFI (P < .001). The mean time (s) to reach the target point were 146.4 ± 90.1 and 42.7 ± 40.5 for conventional VFI and RL-VFI (P = .004). The mean preference scores were 4.2 ± 1.3 and 8.7 ± 1.3 for conventional VFI and RL-VFI (P = .004).

CONCLUSION

SBT program using RL-VFI might improve the comfort levels of trainees for VFI with CT approach. It would be helpful for trainees to practice VFI before trying it on actual patients.

LEVEL OF EVIDENCE

N/A.

Changes in performance during repeated in-situ simulations with different cases

Introduction

The aim was to describe changes in the performance of clinical actions, during repeated in-situ simulations with different cases, by teams of healthcare professionals with different experiences of the systematic clinical observation of deteriorating patients, after an introduction to the Airways, Breathing, Circulation, Disability, Environment/Exposure (ABCDE) approach.

Methods

A descriptive observational study was conducted of repeated in-situ simulations using a patient simulator (SimMan 3G), carried out by teams in a public nursing home (NH, least experienced), an out-of-hours general practice (OOH-GP) service and a hospital emergency department (ED, most experienced). The cases had similar clinical presentations but different underlying diagnoses unknown to the teams. Four blinded clinical experts independently assessed the simulations on the basis of transcripts, providing comments, an overall score and scores for the clinical actions.

Results

The assessors commented on the overall lack of a systematic ABCDE approach in the NH and OOH-GP in all simulations, while the comments for the ED concerned the choice of treatment. Across the teams, the overall score was highest in the first simulation and second highest in the third simulation. The team in the NH received low overall scores for all simulations, but the last simulation received markedly better scores on the clinical actions. The teams in the OOH-GP and ED had no such clear pattern in the scores for clinical actions and thus no indications of improvement with repeated simulations.

Conclusion

The observation in this study was that the overall assessment by the blinded assessors showed no consistent improvement in clinical actions from repeated in-situ simulations, and the teams did not seem to adhere to the ABCDE approach throughout the simulations. This indicates that the teams were not able to apply their newly acquired experiences of using the ABCDE approach from one case to another, different case.

Assessment of a virtual reality temporal bone surgical simulator: a national face and content validity study

BACKGROUND

Trainees in Otolaryngology-Head and Neck Surgery must gain proficiency in a variety of challenging temporal bone surgical techniques. Traditional teaching has relied on the use of cadavers; however, this method is resource-intensive and does not allow for repeated practice. Virtual reality surgical training is a growing field that is increasingly being adopted in Otolaryngology. CardinalSim is a virtual reality temporal bone surgical simulator that offers a high-quality, inexpensive adjunct to traditional teaching methods. The objective of this study was to establish the face and content validity of CardinalSim through a national study.

METHODS

Otolaryngologists and resident trainees from across Canada were recruited to evaluate CardinalSim. Ethics approval and informed consent was obtained. A face and content validity questionnaire with questions categorized into 13 domains was distributed to participants following simulator use. Descriptive statistics were used to describe questionnaire results, and either Chi-square or Fishers exact tests were used to compare responses between junior residents, senior residents, and practising surgeons.

RESULTS

Sixty-two participants from thirteen different Otolaryngology-Head and Neck Surgery programs were included in the study (32 practicing surgeons; 30 resident trainees). Face validity was achieved for 5 out of 7 domains, while content validity was achieved for 5 out of 6 domains. Significant differences between groups (p-value of < 0.05) were found for one face validity domain (realistic ergonomics, p = 0.002) and two content validity domains (teaching drilling technique, p = 0.011 and overall teaching utility, p = 0.006). The assessment scores, global rating scores, and overall attitudes towards CardinalSim, were universally positive. Open-ended questions identified limitations of the simulator.

CONCLUSION

CardinalSim met acceptable criteria for face and content validity. This temporal bone virtual reality surgical simulation platform may enhance surgical training and be suitable for patient-specific surgical rehearsal for practicing Otolaryngologists.

Combining Stereoscopic Video and Virtual Reality Simulation to Maximize Education in Lateral Skull Base Surgery

Mastery of lateral skull base (LSB) surgery requires thorough knowledge of complex, 3-dimensional (3D) microanatomy and techniques. While supervised operation under binocular microscopy remains the training gold standard, concerns over operative time and patient safety often limit novice surgeons’ stereoscopic exposure. Furthermore, most alternative educational resources cannot meet this need. Here we present proof of concept for a tool that combines 3D-operative video with an interactive, stereotactic teaching environment. Stereoscopic video was recorded with a microscope during translabyrinthine approaches for vestibular schwannoma. Digital imaging and communications in medicine (DICOM) temporal bone computed tomography images were segmented using 3D-Slicer. Files were rendered using a game engine software built for desktop virtual reality. The resulting simulation was an interactive immersion combining a 3D operative perspective from the lead surgeon’s chair with virtual reality temporal bone models capable of hands-on manipulation, label toggling, and transparency modification. This novel tool may alter LSB training paradigms.

Development and Evaluation of an Objective Tympanic Membrane Visualization Assessment Technique

OBJECTIVES

To introduce an inexpensive method for objectively evaluating otoscopic visualization of the tympanic membrane wherein learners match what they visualize in standardized patients to tympanic membrane photographs.

METHODS

Two standardized patients had photographs taken of their tympanic membranes using a commercially-available digital otoscope. First- and third-year medical students were asked to perform an otoscopic examination on each patient using a conventional handheld otoscope and to match what they saw with the correct tympanic membrane image among distractor photographs belonging to other patients. The ability of students to match the standardized patients' tympanic membrane to the correct photographs was assessed before and after a didactic training session. These measurements were compared between the two cohort groups for construct validity.

RESULTS

Fifty-one first-year medical students (with no previous otoscopy experience) and 44 third-year medical students (with otoscopy experience from completing pediatric and family medicine clinical clerkships) were recruited to voluntarily participate in this study. At baseline, a larger percentage of third-year students correctly matched both tympanic membranes compared to first-year students (27% vs 8%, P < .01). After otoscopy training, correct matching of both tympanic membranes significantly improved among both first-year students (8-31%, P < .01) and third-year students (27-54%, P < .01).

CONCLUSION

The use of tympanic membrane photographs from standardized patients provides a novel technique for objectively assessing proficiency in otoscopic visualization of the middle ear. The concept is low cost, uses live patients, and can be easily implemented in pre-clinical instruction and beyond.

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.

A Surgical Simulator for Tympanostomy Tube Insertion Incorporating Capacitive Sensing Technology to Track Instrument Placement

We describe a device engineered for realistic simulation of myringotomy and tympanostomy tube insertion that tracks instrument placement and objectively measures operator proficiency. A 3-dimensional computer model of the external ear and cartilaginous external auditory canal was created from a normal maxillofacial computed tomography scan, and models for the bony external auditory canal and tympanic cavity were created with computer-aided design software. Physical models were 3-dimensionally printed from the computer reconstructions. The external auditory canal and tympanic cavity surfaces were coated with conductive material and wired to a capacitive sensor interface. A programmable microcontroller with custom embedded software completed the system. Construct validation was completed by comparing the run times and total sensor contact times of otolaryngology faculty and residents.

A review of simulation applications in temporal bone surgery

Background

Temporal bone surgery is a technically challenging and high-risk procedure in an anatomically complex area. Safe temporal bone surgery emphasizes a consummate anatomic understanding and technique development that requires the guidance of an experienced otologic surgeon and years of practice. Temporal bone simulation can augment otologic surgical training and enable rehearsal of surgical procedures.

Objectives

The purpose of this article is to provide an updated review of temporal bone simulation platforms and their uses.

Data Sources

PubMed literature search. Search terms included temporal bone, temporal bone simulation, virtual reality (VR), and presurgical planning and rehearsal.

Discussion

Various simulation platforms such as cadaveric bone, three-dimensional (3D) printed models, and VR simulation have been used for temporal bone surgery training. However, each simulation method has its drawbacks. There is a need to improve upon current simulation platforms to enhance surgical training and skills assessment, as well as a need to explore other clinically significant applications of simulation, such as preoperative planning and rehearsal, in otologic surgery.

Conclusions

There is no replacement for actual surgical experience, but high-fidelity temporal bone models such as those produced with 3D printing and computer simulation have emerged as promising tools in otolaryngologic surgery. Improvements in the fidelity of both 3D printed and VR simulators as well as integration of a standardized assessment format would allow for an expansion in the use of these simulation platforms in training and assessment.

Level of Evidence

5.

The OpenEar library of 3D models of the human temporal bone based on computed tomography and micro-slicing

Virtual reality surgical simulation of temporal bone surgery requires digitized models of the full anatomical region in high quality and colour information to allow realistic texturization. Existing datasets which are usually based on microCT imaging are unable to fulfil these requirements as per the limited specimen size, and lack of colour information. The OpenEar Dataset provides a library consisting of eight three-dimensional models of the human temporal bone to enable surgical training including colour data. Each dataset is based on a combination of multimodal imaging including Cone Beam Computed Tomography (CBCT) and micro-slicing. 3D reconstruction of micro-slicing images and subsequent registration to CBCT images allowed for relatively efficient multimodal segmentation of inner ear compartments, middle ear bones, tympanic membrane, relevant nerve structures, blood vessels and the temporal bone. Raw data from the experiment as well as voxel data and triangulated models from the segmentation are provided in full for use in surgical simulators or any other application which relies on high quality models of the human temporal bone.