Virtual reality simulation training in temporal bone surgery

Development and Evaluation of a Mixed Reality Model for Training the Retrosigmoid Approach

BACKGROUND

The use of simulation has the potential to accelerate the learning curves and increase the efficiency of surgeons. However, there is currently a scarcity in models dedicated to skull base surgical approaches. Thus, the objective of this study was to develop a cost-effective mixed reality system consisting of an ultrarealistic physical model and augmented reality and evaluate its use in training surgeons on the retrosigmoid approach.

METHODS

The virtual models were developed from images of patients with vestibular schwannoma. The tumor was mirrored to allow bilateral approaches and the model has drawers for repositioning structures, allowing reuse of the material and cost reduction. Pre and posttest assessments were applied to 10 residents and young neurosurgeons, divided into control and test groups. Only the control group was exposed to the model. The difference in scores obtained by participants before and after exposure to the models was considered for analysis and participants in the control group answered self-satisfaction questionnaires.

RESULTS

The mean differences were 4.80 in the control group (95% credibility intervals=1.08-9.79) and 5.43 in the test group (95% credibility intervals=1.67-8.20). The average score of the self-satisfaction questionnaires was 24.0 (23-25).

CONCLUSIONS

The ultrarealistic model efficiently allowed retromastoid access to the cerebellopontine angle. A tendency toward greater gains in performance in the group exposed to the model was verified. Scores from the self-satisfaction questionnaires demonstrated that participants considered the model relevant for neurosurgical training and increased confidence among surgeons.

Virtual temporal bone simulators and their use in surgical training: a narrative review

OBJECTIVE

Temporal bone dissection is a difficult skill to acquire, and the challenge has recently been further compounded by a reduction in conventional surgical training opportunities during the coronavirus disease 2019 pandemic. Consequently, there has been renewed interest in ear simulation as an adjunct to surgical training for trainees. We review the state-of-the-art virtual temporal bone simulators for surgical training.

MATERIALS AND METHODS

A narrative review of the current literature was performed following a Medline search using a pre-determined search strategy.

RESULTS AND ANALYSIS

Sixty-one studies were included. There are five validated temporal bone simulators: Voxel-Man, CardinalSim, Ohio State University Simulator, Melbourne University's Virtual Reality Surgical Simulation and Visible Ear Simulator. The merits of each have been reviewed, alongside their role in surgical training.

CONCLUSION

Temporal bone simulators have been demonstrated to be useful adjuncts to conventional surgical training methods and are likely to play an increasing role in the future.

Use of simulation-based training of surgical technical skills among ENTs: an international YO-IFOS survey

PURPOSE

The aim of this study was to investigate and compare the use of simulation-based technical skills training (SBTST) in the otolaryngology curriculum in different countries, and to explore the needs and opinions about the use of simulation among young otolaryngologists.

METHODS

An e-survey conducted among Young Otolaryngologists of the International Federation of Oto-rhino-laryngological Societies (Yo-IFOS) members.

RESULTS

139 Yo-IFOS members from 51 countries completed the survey. During residency training, 82.7% of respondents have used SBTST on cadavers, 51.8% on physical simulators, and 43.8% on virtual reality simulators. High costs (65.5%), lack of availability (49.2%) and lack of time (25.5%) were the main barriers limiting the practice of SBTST. These barriers also limited teaching using simulation. Sinonasal surgery (72.7%), temporal bone surgery (67.6%), and head/neck surgery (44.6%) were significantly more frequently taught using SBTST than suspension microlaryngoscopy (25.9%) and pediatric surgery (22.3%) (p < 0.001). The procedures rated as the most important to learn through SBTST were tracheotomy (50.4%), emergency cricothyroidotomy (48.9%), and rigid bronchoscopy (47.5%). On an analogic visual scale (0-100) for the question "how important will simulation be for future ENTs in surgical training?", the mean score was 79.5/100 (± 23.3), highlighting the positive attitude toward the use of SBTST in otorhinolaryngology training.

CONCLUSION

SBTST is an attractive learning and teaching method in otorhinolaryngology, but associated costs, lack of access, and lack of time are the main barriers limiting its use. Emergency procedures are key technical skills to be learned using simulation but in some cases, lack relevant simulators for training.

Training in temporal bone drilling

Acquiring surgical experience in the operating room is increasingly difficult. Simulation of temporal bone drilling is therefore essential, and more and more widely used. The aim of this review is to clarify the limitations of classical surgical training, and to describe the different types of simulation available for temporal bone drilling. Systematic Medline search used the terms: "temporal bone" and training and surgery; "temporal bone" and training and drilling. Seventy-one of the 467 articles identified were relevant for this review. Various temporal bone simulators have been created to get around the limitations (ethical, financial, cultural, working time) of temporal bone drilling. They can be classified as cadaver, animal, physical or virtual models. The main advantages of physical and virtual prototyping are their ease of access, the possibility of repeating gestures on a standardised model, and the absence of ethical issues. Validation is essential before these simulators can be included in the curriculum, to ensure efficacy and thus improve patient safety in the operating room.

Augmented reality in neurosurgical navigation: a survey

BACKGROUND

Neurosurgery has exceptionally high requirements for minimally invasive and safety. This survey attempts to analyze the practical application of AR in neurosurgical navigation. Also, this survey describes future trends in augmented reality neurosurgical navigation systems.

METHODS

In this survey, we searched related keywords "augmented reality", "virtual reality", "neurosurgery", "surgical simulation", "brain tumor surgery", "neurovascular surgery", "temporal bone surgery", and "spinal surgery" through Google Scholar, World Neurosurgery, PubMed and Science Direct. We collected 85 articles published over the past five years in areas related to this survey.

RESULTS

Detailed study has been conducted on the application of AR in neurosurgery and found that AR is constantly improving the overall efficiency of doctor training and treatment, which can help neurosurgeons learn and practice surgical procedures with zero risks.

CONCLUSIONS

Neurosurgical navigation is essential in neurosurgery. Despite certain technical limitations, it is still a necessary tool for the pursuit of maximum security and minimal intrusiveness. This article is protected by copyright. All rights reserved.

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.

Integrating Stereoscopic Video with Modular 3D Anatomic Models for Lateral Skull Base Training

Introduction  Current virtual reality (VR) technology allows the creation of instructional video formats that incorporate three-dimensional (3D) stereoscopic footage.Combined with 3D anatomic models, any surgical procedure or pathology could be represented virtually to supplement learning or surgical preoperative planning. We propose a standalone VR app that allows trainees to interact with modular 3D anatomic models corresponding to stereoscopic surgical videos. Methods  Stereoscopic video was recorded using an OPMI Pentero 900 microscope (Zeiss, Oberkochen, Germany). Digital Imaging and Communications in Medicine (DICOM) images segmented axial temporal bone computed tomography and each anatomic structure was exported separately. 3D models included semicircular canals, facial nerve, sigmoid sinus and jugular bulb, carotid artery, tegmen, canals within the temporal bone, cochlear and vestibular aqueducts, endolymphatic sac, and all branches for cranial nerves VII and VIII. Finished files were imported into the Unreal Engine. The resultant application was viewed using an Oculus Go. Results  A VR environment facilitated viewing of stereoscopic video and interactive model manipulation using the VR controller. Interactive models allowed users to toggle transparency, enable highlighted segmentation, and activate labels for each anatomic structure. Based on 20 variable components, a value of 1.1 × 10 ¹² combinations of structures per DICOM series was possible for representing patient-specific anatomy in 3D. Conclusion  This investigation provides proof of concept that a hybrid of stereoscopic video and VR simulation is possible, and that this tool may significantly aid lateral skull base trainees as they learn to navigate a complex 3D surgical environment. Future studies will validate methodology.

Virtual Functional Endoscopic Sinus Surgery Simulation with 3D-Printed Models for Mixed-Reality Nasal Endoscopy

The surgeon's knowledge of a patient's individual anatomy is critical in skull base surgery. Trainees and experienced surgeons can benefit from surgical simulation; however, current models are expensive and impractical for widespread use. In this study, we report a next-generation mixed-reality surgical simulator. We segmented critical anatomic structures for 3-dimensional (3D) models to develop a modular teaching tool. We then developed a navigation tracking system utilizing a 3D-printed endoscope as a trackable virtual-reality (VR) controller and validated the accuracy on VR and 3D-printed skull models within 1 cm. We combined VR and augmented-reality visual cues with our 3D physical model to simulate sinus endoscopy and highlight segmented structures in real time. This report provides evidence that a mixed-reality simulator combining VR and 3D-printed models is feasible and may prove useful as an educational tool that is low cost and customizable.

Otologic Skills Training

This article presents a summary of the current simulation training for otologic skills. There is a wide variety of educational approaches, assessment tools, and simulators in use, including simple low-cost task trainers to complex computer-based virtual reality systems. A systematic approach to otologic skills training using adult learning theory concepts, such as repeated and distributed practice, self-directed learning, and mastery learning, is necessary for these educational interventions to be effective. Future directions include development of measures of performance to assess efficacy of simulation training interventions and, for complex procedures, improvement in fidelity based on educational goals.

Construct, Face, and Content Validation on Voxel-Man® Simulator for Otologic Surgical Training

Objective. To assess the face, content, and construct validity of the Voxel-Man TempoSurg Virtual Reality simulator. Participants and Methods. 74 ear, nose, and throat (ENT) surgeons participated. They were assigned to one of two groups according to their level of expertise: the expert group (n = 16) and the novice group (n = 58). The participants performed four temporal bone dissection tasks on the simulator. Performances were assessed by a global score and then compared to assess the construct validity of the simulator. Finally, the expert group assessed the face and content validity by means of a five-point Likert-type scale. Results. experienced surgeons performed better (p < .01) and faster (p < .001) than the novices. However, the groups did not differ in terms of bone volume removed (p = .11) or number of injuries (p = .37). 93.7% of experienced surgeons stated they would recommend this simulator for anatomical learning. Most (87.5%) also thought that it could be integrated into surgical training. Conclusion. The Voxel-Man TempoSurg Virtual Reality simulator constitutes an interesting complementary tool to traditional teaching methods for training in otologic surgery.

Evaluating the Effect of Virtual Reality Temporal Bone Simulation on Mastoidectomy Performance: A Meta-analysis

Background

The increasing prevalence of virtual reality simulation in temporal bone surgery warrants an investigation to assess training effectiveness.

Objectives

To determine if temporal bone simulator use improves mastoidectomy performance.

Data Sources

Ovid Medline, Embase, and PubMed databases were systematically searched per the PRISMA guidelines.

Review Methods

Inclusion criteria were peer-reviewed publications that utilized quantitative data of mastoidectomy performance following the use of a temporal bone simulator. The search was restricted to human studies published in English. Studies were excluded if they were in non-peer-reviewed format, were descriptive in nature, or failed to provide surgical performance outcomes. Meta-analysis calculations were then performed.

Results

A meta-analysis based on the random-effects model revealed an improvement in overall mastoidectomy performance following training on the temporal bone simulator. A standardized mean difference of 0.87 (95% CI, 0.38-1.35) was generated in the setting of a heterogeneous study population ( I2 = 64.3%, P < .006).

Conclusion

In the context of a diverse population of virtual reality simulation temporal bone surgery studies, meta-analysis calculations demonstrate an improvement in trainee mastoidectomy performance with virtual simulation training.

Current Status of Simulation in Otolaryngology: A Systematic Review

OBJECTIVE

Otolaryngology is a highly technical and demanding specialty and the requirements for surgical trainees to acquire proficiency remains challenging. Simulation has been purported to be an effective tool in assisting with this. The aim of this systematic review is to identify the available otolaryngology simulators, their status of validation, and evaluation the level of evidence behind each training model and thereby establish a level of recommendation.

DESIGN

PubMed, ERIC, and Google Scholar databases were searched for articles that described otolaryngology simulators or training models between 1980 and April 2016. Any validation studies for simulators were also retrieved. Titles and abstracts were screened for relevance using the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines. Level of evidence (LoE) and Level of recommendation (LoR) was awarded to each study and model, respectively.

RESULTS

A total of 70 studies were identified describing 64 simulators. Out of these, at least 54 simulators had 1 validation study. Simulators for the ear and temporal bone surgery were the most common (n = 32), followed by laryngeal and throat (n = 20) and endoscopic sinus surgery (n = 12). Face validity was evaluated by 29 studies, 20 attempted to show construct, 20 assessed content, 20 transfer, and only 2 assessed concurrent validity. Of the validation assessments, 2 were classified as Level 1b, 10 Level 2a, and 48 Level 2b. No simulators received the highest LoR, but 8 simulators received a LoR of 2.

CONCLUSIONS

Despite the lack of evidence in outcome studies and limited number of high-validity otolaryngology simulators, the role of simulation continues to grow across surgical specialties Hence, it is imperative that the simulators are of high validity and construct for trainees to practice and rehearse surgical skills to develop confidence.

Expert subjective comparison of haptic models for bone-drill interaction

PURPOSE

A haptic algorithm to simulate the interaction between a surgical drill and bone using a constraint-based algorithm has been previously demonstrated. However, there has been no blinded study to determine whether this algorithm is preferred by professionals who commonly use this type of system METHODS: Fourteen otologic surgeons were presented with a spring-damper model and a constraint-based model of drill-bone interaction rendered on a low-cost haptic device with only linear feedback. The participants were blinded as to what algorithm they were using. They then answered survey questions about their opinions of the models.

RESULTS

The surgeons overwhelmingly preferred the constraint-based model. They generally preferred the constraint-based model in the individual questions as well.

CONCLUSIONS

Follow-up work can be done to fine-tune the parameters in the model, but this study shows that a sophisticated algorithm can make a significant difference even on a low-fidelity haptic device.

A review of simulation platforms in surgery of the temporal bone

BACKGROUND

Surgery of the temporal bone is a high-risk activity in an anatomically complex area. Simulation enables rehearsal of such surgery. The traditional simulation platform is the cadaveric temporal bone, but in recent years other simulation platforms have been created, including plastic and virtual reality platforms.

OBJECTIVE OF REVIEW

To undertake a review of simulation platforms for temporal bone surgery, specifically assessing their educational value in terms of validity and in enabling transition to surgery.

TYPE OF REVIEW

Systematic qualitative review.

SEARCH STRATEGY

Search of the Pubmed, CINAHL, BEI and ERIC databases.

EVALUATION METHOD

Assessment of reported outcomes in terms of educational value.

RESULTS

A total of 49 articles were included, covering cadaveric, animal, plastic and virtual simulation platforms. Cadaveric simulation is highly rated as an educational tool, but there may be a ceiling effect on educational outcomes after drilling 8-10 temporal bones. Animal models show significant anatomical variation from man. Plastic temporal bone models offer much potential, but at present lack sufficient anatomical or haptic validity. Similarly, virtual reality platforms lack sufficient anatomical or haptic validity, but with technological improvements they are advancing rapidly.

CONCLUSIONS

At present, cadaveric simulation remains the best platform for training in temporal bone surgery. Technological advances enabling improved materials or modelling mean that in the future plastic or virtual platforms may become comparable to cadaveric platforms, and also offer additional functionality including patient-specific simulation from CT data.

Correlations of External Landmarks With Internal Structures of the Temporal Bone

HYPOTHESIS

The internal anatomy of a temporal bone could be inferred from external landmarks.

BACKGROUND

Mastoid surgery is an important skill that ENT surgeons need to acquire. Surgeons commonly use CT scans as a guide to understanding anatomical variations before surgery. Conversely, in cases where CT scans are not available, or in the temporal bone laboratory where residents are usually not provided with CT scans, it would be beneficial if the internal anatomy of a temporal bone could be inferred from external landmarks.

METHODS

We explored correlations between internal anatomical variations and metrics established to quantify the position of external landmarks that are commonly exposed in the operating room, or the temporal bone laboratory, before commencement of drilling. Mathematical models were developed to predict internal anatomy based on external structures.

RESULTS

From an operating room view, the distances between the following external landmarks were observed to have statistically significant correlations with the internal anatomy of a temporal bone: temporal line, external auditory canal, mastoid tip, occipitomastoid suture, and Henle's spine. These structures can be used to infer a low lying dura mater (p = 0.002), an anteriorly located sigmoid sinus (p = 0.006), and a more lateral course of the facial nerve (p < 0.001). In the temporal bone laboratory view, the mastoid tegmen and sigmoid sinus were also regarded as external landmarks. The distances between these two landmarks and the operating view external structures were able to further infer the laterality of the facial nerve (p < 0.001) and a sclerotic mastoid (p < 0.001). Two nonlinear models were developed that predicted the distances between the following internal structures with a high level of accuracy: the distance from the sigmoid sinus to the posterior external auditory canal (p < 0.001) and the diameter of the round window niche (p < 0.001).

CONCLUSION

The prospect of encountering some of the more technically challenging anatomical variants encountered in temporal bone dissection can be inferred from the distance between external landmarks found on the temporal bone. These relationships could be used as a guideline to predict challenges during drilling and choosing appropriate temporal bones for dissection.