Mixed reality temporal bone surgical dissector: mechanical design

Clinical situations for which 3D printing is considered an appropriate representation or extension of data contained in a medical imaging examination: neurosurgical and otolaryngologic conditions

BACKGROUND

Medical three dimensional (3D) printing is performed for neurosurgical and otolaryngologic conditions, but without evidence-based guidance on clinical appropriateness. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (SIG) provides appropriateness recommendations for neurologic 3D printing conditions.

METHODS

A structured literature search was conducted to identify all relevant articles using 3D printing technology associated with neurologic and otolaryngologic conditions. Each study was vetted by the authors and strength of evidence was assessed according to published guidelines.

RESULTS

Evidence-based recommendations for when 3D printing is appropriate are provided for diseases of the calvaria and skull base, brain tumors and cerebrovascular disease. Recommendations are provided in accordance with strength of evidence of publications corresponding to each neurologic condition combined with expert opinion from members of the 3D printing SIG.

CONCLUSIONS

This consensus guidance document, created by the members of the 3D printing SIG, provides a reference for clinical standards of 3D printing for neurologic conditions.

[Residency is a fundamental stage of professional training of an otorhinolaryngologist]

Systematic analysis of various indicators of the educational process becomes important to assess the effectiveness of the training of residents. One of the most common tools for monitoring the effectiveness of the educational process is a questionnaire of students.

OBJECTIVE

To analyze the results of the assessment of the quality of training in the residency of the Sverzhevky Research Clinical Institute of Otorhinolaryngology according to the survey of residents.

MATERIAL AND METHODS

The study includes the results of an anonymous questionnaire survey of a sample group of residents of the residency of the Sverzhevky Research Clinical Institute of Otorhinolaryngology of the second year of study.

RESULTS

The data obtained allow us to judge the satisfaction with the quality of training of the absolute majority of the interviewed residents, their active use of specialized electronic search engines, a high assessment of the level of lectures, the desire to improve their surgical training. The importance for the professional development of residents of participation in weekly scientific and clinical conferences of the Sverzhevky Research Clinical Institute of Otorhinolaryngology, meetings of the Moscow Scientific Society of Otorhinolaryngologists, traditional annual scientific and practical conferences of otorhinolaryngologists of Moscow, as well as in the activities of the Youth Council of the Institute is noted.

CONCLUSION

The results of the survey create prerequisites for improving the educational process, the formation of professional competencies and readiness for independent work among residents.

Comparison of Summative Temporal Bone Dissection Scales Demonstrate Equivalence

Introduction  Temporal bone surgery is a unique and complicated surgical skill that requires extensive training. There is an educational requirement to maximize trainee experience and provide effective feedback.

Objective  We evaluate three temporal bone dissection scales for efficacy, reliability, and accuracy in identifying resident skill during temporal bone surgery.

Methods  Residents of various skill levels performed a mastoidectomy with posterior tympanotomy on identic 3D-printed temporal bone models. Four blinded otologic surgeons evaluated each specimen at two separate intervals using three separate dissection scales: the Welling Scale (WS), the Iowa Temporal Bone Assessment Tool (ITBAT), and the CanadaWest Scale (CWS). Scores from each scale were compared in their ability to accurately separate residents by skill level, inter- and intrarater reliability, and efficiency in application.

Results  Nineteen residents from 9 postgraduate programs participated. Assessment was clustered into junior (postgraduate year or PGY 1, 2), intermediate (PGY 3) and senior resident (PGY 4, 5) cohorts. Analysis of variance (ANOVA) found significant differences between cohort performance ( p  < 0.05) for all 3 scales considering the PGY level and the subjective account of temporal bone surgical experience. The inter-rater reliability was consistent across each scale. The intrarater reliability was comparable between the CWS (0.711) and the WS (0.713), but not the ITBAT (0.289). Time (in seconds) to complete scoring for each scale was also comparable between the CWS (42.7 ± 16.8), the WS (76.6 ± 14.5), and the ITBAT (105.6 ± 38.9).

Conclusion  All three scales demonstrated construct validity and consistency in performance, and consideration should be given to judicious use in training.

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.

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.

Exploration of temporal bone anatomy using mixed reality (HoloLens): development of a mixed reality anatomy teaching resource prototype

Mixed reality (MR), a technology which supplements the real world with virtual objects, is increasingly becoming available as a teaching tool in medical education. The Microsoft HoloLens device allows operators to experience MR using a head-mounted device without interfering with their physical reality, stimulating a realistic learning experience using virtual objects. This project aimed to develop a MR anatomy teaching application with HoloLens for exploring the anatomy of the temporal bone. The educational application was developed from a multidisciplinary collaboration between undergraduate and postgraduate students across several academic disciplines with Medtronic, a medical technology company. 3D anatomical models were built using ZBrush and Blender, while the HoloLens1 application was developed using Windows 10, Visual Studio 2017, Unity and Mixed Reality Toolkit (MRTK). Modules developed within the application included a basic HoloLens tutorial, a virtual temporal bone with surgical anatomy landmarks and free drilling of the temporal bone. The basic tutorial allows the operator to adapt to the MR environment prior to exploring the anatomical landmarks of the 3D temporal bone. The free drilling of the temporal bone using vertex displacement and texture stretching replicates a real-time bone drilling experience and allows the operator to explore the anatomical relationship between different otological structures.

Preliminary application of mxed reality in neurosurgery: Development and evaluation of a new intraoperative procedure

During neurological surgery, neurosurgeons have to transform the two-dimensional (2D) sectional images into three-dimensional (3D) structures at the cognitive level. The complexity of the intracranial structures increases the difficulty and risk of neurosurgery. Mixed reality (MR) applications reduce the obstacles in the transformation from 2D images to 3D visualization of anatomical structures of central nervous system. In this study, the holographic image was established by MR using computed tomography (CT), computed tomography angiography (CTA) and magnetic resonance imaging (MRI) data of patients. The surgeon's field of vision was superimposed with the 3D model of the patient's intracranial structure displayed on the mixed reality head-mounted display (MR-HMD). The neurosurgeons practiced and evaluated the feasibility of this technique in neurosurgical cases. We developed the segmentation image masks and texture mapping including brain tissue, intracranial vessels, nerves, tumors, and their relative positions by MR technologies. The results showed that the three-dimensional imaging is in a stable state in the operating room with no significant flutter and blur. And the neurosurgeon's feedback on the comfort of the equipment and the practicality of the technology was satisfactory. In conclusion, MR technology can holographically construct a 3D digital model of patient's lesions and improve the anatomical perception of neurosurgeons during craniotomy. The feasibility of the MR-HMD application in neurosurgery is confirmed.

Mixed Reality-Based Preoperative Planning for Training of Percutaneous Transforaminal Endoscopic Discectomy: A Feasibility Study

OBJECTIVE

To explore the effect of preoperative planning using mixed reality (MR) on training of percutaneous transforaminal endoscopic discectomy (PTED).

METHODS

Before the training, we invited an experienced chief physician to plan the puncture path of PTED on the X-ray films of the lumbar spine model and the 3D Slicer platform, respectively, and used this as the standard to guide trainees. In the aggregate, 60 young residents were randomly divided into Group A (N = 30) and Group B (N = 30). Group A learned the 2-dimensional standard planning route, whereas Group B learned the standard route planning based on MR through the 3D Slicer platform. Then, trainees were asked to conduct PTED puncture on a lumbar spine model. Questionnaires were distributed to trainees before and after the training. During the training, puncture times, operating time (minutes), and fluoroscopy times were recorded.

RESULTS

After the training, it was obvious that more trainees showed their recognition of MR, believing that MR could help preoperative planning and training of PTED. Their high satisfaction with the training indicated the success of our training. Moreover, puncture times, operating time (minutes), and fluoroscopy times of Group B were significantly lower than those of Group A.

CONCLUSIONS

MR technology contributes to preoperative planning of PTED and is beneficial in the training of PTED. It significantly reduces puncture times and fluoroscopy times, providing a standardized method for the training of PTED.

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.

Elements of virtual temporal bone surgery: Manipulandum format may be more important to surgeons than haptic device force capabilities

Background

Temporal bone simulations are critiqued for poor drill‐bone interaction. This project appraises the import of increasing haptic device and manipulandum fidelity on the perceived realism of drilling a virtual temporal bone.

Virtual surgical contact forces rely on haptic device fidelity and are transmitted through a manipulandum. With identical software, both device hardware and manipulandum may each contribute to realism. We compare the three degrees of freedom (DOF), 3N Geomagic Touch (3D Systems, SC) to a 6DOF, 5.5N HD² (Quanser, ON) with the both standard (“HD²–Standard”) and in‐house customized otic drill manipulandum (“HD²–Modified”).

Methods

Six otologic surgeons performed three virtual mastoidectomy surgeries on a temporal bone surgical simulator. The HD² manipulandum was modified for attached otic drill with gravity compensation and requisite mechanical modifications. Surgeons, in random order, performed the dissection with the different hardware platforms.

Results

Two‐tailed t‐tests demonstrate that for the acoustic properties of each simulation, the HD²–Modified manipulandum was favored (p ≤ 0.0004). For overall similarity of bone, both HD²–Standard (p ≤ 0.05) HD²–Modified (p ≤ 0.03)) were favored over the Geomagic; however they were not appreciably different when directly compared to each other. There was no preference for increasing haptic device fidelity in virtual drill bone interaction.

In forced rank, users favored the HD²–Modified in osseus, vibrational and overall realism, as well as being preferred for education and preoperative rehearsal (p ≤ 0.0164).

Conclusion

Increasing manipulandum realism was favored. However surprisingly, there was no preference for increased device fidelity, illustrating incremental stiffness had nominal impact. There may be a ceiling to drill bone interaction in virtual haptic simulation.

Level of Evidence

2b.

Simulation training in neurosurgery: advances in education and practice

The current simulation technology used for neurosurgical training leaves much to be desired. Significant efforts are thoroughly exhausted in hopes of developing simulations that translate to give learners the "real-life" feel. Though a respectable goal, this may not be necessary as the application for simulation in neurosurgical training may be most useful in early learners. The ultimate uniformly agreeable endpoint of improved outcome and patient safety drives these investments. We explore the development, availability, educational taskforces, cost burdens and the simulation advancements in neurosurgical training. The technologies can be directed at achieving early resident milestones placed by the Accreditation Council for Graduate Medical Education. We discuss various aspects of neurosurgery disciplines with specific technologic advances of simulation software. An overview of the scholarly landscape of the recent publications in the realm of medical simulation and virtual reality pertaining to neurologic surgery is provided. We analyze concurrent concept overlap between PubMed headings and provide a graphical overview of the associations between these terms.