The role of virtual reality in surgical training in otorhinolaryngology

Live Virtual Surgery and Virtual Reality in Surgery: Potential Applications in Hand Surgery Education

Accelerated in part by the coronavirus disease 2019 pandemic, medical education has increasingly moved into the virtual sphere in recent years. Virtual surgical education encompasses several domains, including live virtual surgery and virtual and augmented reality. These technologies range in complexity from streaming audio and video of surgeries in real-time to fully immersive virtual simulations of surgery. This article reviews the current use of virtual surgical education and its possible applications in hand surgery. Applications of virtual technologies for preoperative planning and intraoperative guidance, as well as care in underresourced settings, are discussed. The authors describe their experience creating a virtual surgery subinternship with live virtual surgeries. There are many roles virtual technology can have in surgery, and this review explores potential value these technologies may have in hand surgery.

Impact of Prolonged Operative Time on Complications Following Endoscopic Sinonasal Surgery

OBJECTIVE

To determine how prolonged operative time (POT) impacts 30-day outcomes in patients undergoing endoscopic sinonasal surgery (ESNS).

STUDY DESIGN

Retrospective study.

METHODS

Data from patients who underwent ESNS (nonsinus, sinus, and extended sinus) between 2005 to 2018 were collected from the American College of Surgeons National Surgical Quality Improvement database. Univariate and multivariate analyses were performed to evaluate the effect of POT on postoperative outcomes.

RESULTS

Among 1,994 ESNS cases, 495 nonsinus procedures, 1,191 sinus procedures, and 308 extended sinus procedures were identified. Median OT was 90 minutes (interquartile range [IQR], 51-165 minutes) for nonsinus procedures, 113 minutes (IQR, 66-189 minutes) for sinus procedures, and 187 minutes (IQR, 137-251 minutes) for extended sinus procedures. Other than older age (P = .008), POT was not significantly associated with baseline demographics and comorbidities for patients undergoing non-sinus procedures. Older age (P < .001), White and Black race (P < .001), ASA physical classifications III or IV (P < .001), and several preoperative comorbidities, including obesity (P = .045), and hypertension (P < .001) were associated with POT for sinus procedures. Older age (P = .030), male sex (P = .010), and lower body mass index (P = .004) were associated with POT for extended sinus procedures. After risk-adjustment, POT was independently associated with prolonged hospital stay (LOS) for all procedure categories, and associated with overall surgical complications and postoperative bleeding for sinus and extended sinus procedures specifically.

CONCLUSION

POT is independently associated with several adverse outcomes following ESNS, including prolonged LOS, overall surgical complications, and bleeding. Preoperative planning should include optimizing modifiable patient risk factors for POT and identifying surgeon-specific factors to enhance surgical efficiency.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:51-58, 2023.

How, for Whom, and in Which Contexts or Conditions Augmented and Virtual Reality Training Works in Upskilling Health Care Workers: Realist Synthesis

BACKGROUND

Using traditional simulators (eg, cadavers, animals, or actors) to upskill health workers is becoming less common because of ethical issues, commitment to patient safety, and cost and resource restrictions. Virtual reality (VR) and augmented reality (AR) may help to overcome these barriers. However, their effectiveness is often contested and poorly understood and warrants further investigation.

OBJECTIVE

The aim of this review is to develop, test, and refine an evidence-informed program theory on how, for whom, and to what extent training using AR or VR works for upskilling health care workers and to understand what facilitates or constrains their implementation and maintenance.

METHODS

We conducted a realist synthesis using the following 3-step process: theory elicitation, theory testing, and theory refinement. We first searched 7 databases and 11 practitioner journals for literature on AR or VR used to train health care staff. In total, 80 papers were identified, and information regarding context-mechanism-outcome (CMO) was extracted. We conducted a narrative synthesis to form an initial program theory comprising of CMO configurations. To refine and test this theory, we identified empirical studies through a second search of the same databases used in the first search. We used the Mixed Methods Appraisal Tool to assess the quality of the studies and to determine our confidence in each CMO configuration.

RESULTS

Of the 41 CMO configurations identified, we had moderate to high confidence in 9 (22%) based on 46 empirical studies reporting on VR, AR, or mixed simulation training programs. These stated that realistic (high-fidelity) simulations trigger perceptions of realism, easier visualization of patient anatomy, and an interactive experience, which result in increased learner satisfaction and more effective learning. Immersive VR or AR engages learners in deep immersion and improves learning and skill performance. When transferable skills and knowledge are taught using VR or AR, skills are enhanced and practiced in a safe environment, leading to knowledge and skill transfer to clinical practice. Finally, for novices, VR or AR enables repeated practice, resulting in technical proficiency, skill acquisition, and improved performance. The most common barriers to implementation were up-front costs, negative attitudes and experiences (ie, cybersickness), developmental and logistical considerations, and the complexity of creating a curriculum. Facilitating factors included decreasing costs through commercialization, increasing the cost-effectiveness of training, a cultural shift toward acceptance, access to training, and leadership and collaboration.

CONCLUSIONS

Technical and nontechnical skills training programs using AR or VR for health care staff may trigger perceptions of realism and deep immersion and enable easier visualization, interactivity, enhanced skills, and repeated practice in a safe environment. This may improve skills and increase learning, knowledge, and learner satisfaction. The future testing of these mechanisms using hypothesis-driven approaches is required. Research is also required to explore implementation considerations.

Application of virtual reality in neurosurgery: Patient missing. A systematic review

Virtual reality (VR) technology had its earliest developments in the 1970s in the U.S. Air Force and has since evolved into a budding area of scientific research with many practical medical purposes. VR shows a high potential to benefit to learners and trainees and improve surgery through enhanced preoperative planning and efficiency in the operating room. Neurosurgery is a field of medicine in which VR has been accepted early on as a useful and promising tool for neuro-navigation planning. Through recent technological developments, VR further increased its level of immersion, accessibility and intuitive use for surgeons and students and now reveals a therapeutic potential for patients. In this paper, we systematically reviewed the neurosurgery literature regarding the use of VR as an assistance for surgery or a tool centered on patients' care. A literature search conducted according to PRISMA guidelines resulted in the screening of 125 abstracts and final inclusion of 100 original publications reviewed. The review shows that neurosurgeons are now relatively familiar with VR technologies (N = 95 articles) for their training and practice. VR technologies are useful for education, pain management and rehabilitation in neurosurgical patients. Nevertheless, the current patient-oriented use of VR remains limited (N = 5 articles). Successful surgery does not only depend on the surgeon's skills and preparation, but also on patients' education, comfort, empowerment and care. Therefore further clinical research is needed to promote the direct use of VR technologies by patients in neurosurgery.

Delivering epilepsy care in low-resource settings: the role of technology

INTRODUCTION

The implementation of technology in the field of epileptology has traditionally focused on its use for diagnosis and treatment and has, unsurprisingly, been capital-intensive, making it therefore mainly implementable in advanced high-income countries. Because of technological innovations over the past 20 years there has been almost a paradigm shift, particularly in access to and the potential for implementing relevant technology in lesser developed environments. Nearly 80% of people living with epilepsy live in low and middle-income countries.

AREAS COVERED

The challenge and the purpose of this paper is to discuss how technology can be implemented into lesser-resourced contexts not only cost-effectively but in a cost-saving way while also building capacity and thus sustainability.

EXPERT OPINION

The rate of technological advancement presents the risk of progressive widening of the technology and care gaps between advanced and lesser developed regions. Implementing technology is both about finding relevant appropriate technologies for the individual contexts of a diverse range of countries but also about repurposing low-tech technologies for application in epilepsy care in these areas. Finally exciting advances such as autonomous driving, digital twinning and robotic surgery will likely transform epilepsy care in several lower-resourced settings in the next 5-10 years.

[Time management in operating rooms-a cross-sectional study to evaluate estimated and objective durations of otorhinolaryngologic surgical procedures]

Hintergrund

Die Gestaltung des Operations(Op.)-Programms im klinischen Alltag ist von hoher Wichtigkeit für die Wirtschaftlichkeit. Gleichzeitig muss die Einhaltung von Arbeitszeiten unterschiedlicher Berufsgruppen berücksichtigt werden.

Ziel der Arbeit

Um Fehlerquellen bei der Planung aufzudecken, wurden durch Chirurgen geschätzte mit objektiv erhobenen Zeiten (u. a. Schnitt-Naht-Zeit) verglichen.

Material und Methoden

In einer retrospektiven Analyse wurden 1809 Operationen im Jahr 2018 (22 verschiedene Op.-Arten) durch 31 Operateure (12 Fach- [FÄ] und 19 Assistenzärzte [AÄ]) hinsichtlich ihrer Dauer verglichen und mittels Mann-Whitney-U-Test auf Signifikanz geprüft.

Ergebnisse

Der Vergleich der objektiven Zeiten von FÄ und AÄ zeigt signifikante Unterschiede in der Schnitt-Naht-Zeit bzw. der Summe aus Schnitt-Naht-Zeit und Zeit der chirurgischen Maßnahmen für 6 von 15 Op.-Arten (p < 0,001). Die durch FÄ geschätzte Nachbereitungszeit wich bei 2 von 22 Op.-Arten von der objektiven Zeit ab (p < 0,05), die durch AÄ geschätzte Zeit bei 7 von 15 Op.-Arten (p < 0,05). Hinsichtlich der Schnitt-Naht-Zeit verschätzten sich FÄ bei 7 von 22 (p < 0,05), AÄ bei 3 von 15 (p < 0,05) Op.-Arten. Die durch FÄ geschätzte Vorbereitungszeit wich bei 16 von 22 Op.-Arten signifikant von der objektiven Zeit ab (p < 0,05), bei AÄ bei 7 von 15 (p < 0,001). Vor- und Nachbereitungszeiten wurden durch FÄ unter‑, Schnitt-Naht-Zeiten überschätzt. AÄ unterschätzten alle Zeiten.

Schlussfolgerung

Bei der OP-Planung muss die Erfahrung des durchführenden Chirurgen berücksichtigt werden. Eine Verbesserung durch verminderte subjektive Fehleinschätzung kann möglicherweise mithilfe spezieller Algorithmen gelingen.

Face, Content, and Construct Validity of a Virtual Reality Otoscopy Simulator and Applicability to Medical Training

Objective

Otologic diseases are common in all age groups and can significantly impair the function of this important sensory organ. To make a correct diagnosis, the correct handling of the otoscope and a correctly performed examination are essential. A virtual reality simulator could make it easier to teach this difficult-to-teach skill. The aim of this study was to assess the face, content, and construct validity of the novel virtual reality otoscopy simulator and the applicability to otologic training.

Study Design

Face and content validity was assessed with a questionnaire. Construct validity was assessed in a prospectively designed controlled trial.

Setting

Training for medical students at a tertiary referral center.

Method

The questionnaire used a 6-point Likert scale. The otoscopy was rated with a modified Objective Structured Assessment of Technical Skills. Time to complete the task and the percentage of the assessed eardrum surface were recorded.

Results

The realism of the simulator and the applicability to medical training were assessed across several items. The ratings suggested good face and content validity as well as usefulness and functionality of the simulator. The otolaryngologists significantly outperformed the student group in all categories measured (P < .0001), suggesting construct validity of the simulator.

Conclusion

In this study, we could demonstrate face, content, and construct validity for a novel high-fidelity virtual reality otoscopy simulator. The results encourage the use of the otoscopy simulator as a complementary tool to traditional teaching methods in a curriculum for medical students.

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.

An Objective Ergonomic Risk Assessment of Surgeons in Real Time While Performing Endoscopic Sinus Surgery

There are increased reports of high prevalence of work related musculoskeletal symptoms in surgeons performing otolaryngology procedures. However, real time ergonomic risk assessment in the OR is difficult due to issues related to sterility, cooperation and acceptance from surgeons. Although such analyses can provide valid risk estimate and guide corrective actions, they are scarce. Hence, this study was undertaken to assess the postural ergonomic risk on RULA in otolaryngologists while performing Functional Endoscopic Sinus Surgery in OR, in real time. A cross sectional, observational multi-centric study was conducted in tertiary referral hospitals. Spinal, shoulder and elbow movements of 10 surgeons performing FESS were measured intraoperatively using orientation sensor-based, motion-analysis system (Noraxon myomotion). Postural ergonomic risk on RULA was computed using the motion analysis data. RULA is a method of quantifying the physical postural risk of the trunk and upper limb based on the postures adopted by an individual during work. 10 surgeons (9 males and 1 female) with the mean (± SD) age of 38 ± 7.5 years participated in the study. The motion analysis data results indicate that the surgeons often adopt awkward spinal and upper extremity postures during the surgery. All the surgeons scored higher than the acceptable RULA score (1 or 2) with the mean RULA scores being in the range of 6-7. The physical ergonomic risk in surgeons performing FESS is high (> 6 on RULA). There is a need for urgent ergonomic attention to the working environment of FESS surgeon.

Rhinology: Simulation Training (Part 1)

Purpose of Review

Recently, there has been an expansion of novel technologies in simulation training. Different models target different aspects of training. The aim of this review was to examine existing evidence about training simulators in rhinology, their incorporation into real training programmes and translation of these skills into the operating room. The first part focuses on the virtual and augmented reality simulators. The second part describes the role of physical (i.e. non-computer-based) models of endoscopic sinus surgery.

Recent Findings

Virtual reality simulators are still evolving and facing challenges due to their inherent cost and lack of realism in terms of the type of haptic feedback they provide. On the other hand, augmented reality seems to be a promising platform with a growing number of applications in preoperative planning, intraoperative navigation and education. Limitations in validity, registration error and level of evidence prevent the adoption of augmented reality on a wider scale or in clinical practice.

Summary

Simulation training is a maturing field that shows reasonable evidence for a number of models. The incorporation of these models into real training programmes requires further evaluation to ensure that training opportunities are being maximized.

Use of Mixed Reality Visualization in Endoscopic Endonasal Skull Base Surgery

BACKGROUND

Neuronavigation systems assist with spatial orientation during endoscopic transnasal skull base surgery, but they require a correlation of 3-dimensional (3D) views with 2-dimensional (2D) radiology studies.

OBJECTIVE

To outline an initial experience with a novel technology platform that provides intraoperative navigation using 3D reconstructions of patient anatomy for endoscopic surgery.

METHODS

A retrospective study of endoscopic anterior skull base and complex paranasal procedures was performed. Data from preoperative computed tomography and magnetic resonance imaging scans were fused to create 3D digital models of patient anatomy. Using the technology developed by Surgical Theater (Mayfield Village, Ohio), these reconstructions were designed to highlight particular anatomic regions of interest. The models were studied to guide the surgical approach and anticipate critical structures.

The reconstructions were linked with the navigational technology created by Brainlab (Munich, Germany) during endoscopic surgery. A dynamic image of the reconstruction was displayed alongside a matching endoscopic camera view. These 2 views could be overlaid to provide an immersive, mixed reality image of the patient's anatomy.

RESULTS

A total of 134 cases were performed. The pathologies included tumors of the anterior skull base or sinonasal cavity, inflammatory sinus disease, and cerebrospinal fluid leaks. Specific anatomic structures, such as the internal carotid arteries and optic nerves, were chosen for enhancement. Surgeons felt that the technology helped to guide the extent of bony dissection and to identify critical structures.

CONCLUSION

We describe the first clinical series of complex skull base pathologies treated using a novel mixed reality platform.

Measurement and prediction of drilling force in fresh human cadaver mandibles: A pilot study

BACKGROUND

Bone drilling is a vital procedure in implant surgery and dental implant training systems based on virtual reality technology.

PURPOSE

Predict and update drilling force in real time based on a virtual dental implant training system and lay the foundation for realizing force feedback in dental implant training instruments.

MATERIALS AND METHODS

An experimental platform was established to measure the drilling force for human mandibles from donors of different ages. Response surface methodology was applied to analyze the drilling force.

RESULTS

Force regression equations for different age groups were acquired. The order of the effects (from greatest to least) of the drilling parameters on the drilling force was the drill bit diameter, feed rate, and rotational speed. To obtain the minimum force, higher rotational speeds, lower feed rates, and smaller diameters were preferred within the range of commonly used medical reference parameters of bone drilling.

CONCLUSION

The experimental data were confirmed to be scientific for the predicted models of drilling force.

Blinded Evaluation of Endoscopic Skill and Instructability After Implementation of an Endoscopic Simulation Experience

Background

Interest in endoscopic simulation is increasing. Past studies have used virtual reality or nonhuman models or residents with varying experience. Our aim was to evaluate the effect of simulation on procedural and psychomotor competence of medical students—surgical novices—performing endoscopic tasks on human cadavers and assess student perceptions.

Methods

Students (n = 22) completed a baseline sinus model skill evaluation graded by 2 blinded Rhinology fellows. Intervention and control groups with equal baselines were assigned. Intervention students practiced endoscopic tasks on the model for 45 minutes minimum over 2 weeks. All students reviewed sinus anatomy/disease and sinus surgery materials. The final cadaver evaluation was similar to the baseline. Fellows graded students on anatomy identification (sinuses, turbinates), psychomotor (navigation, camera alignment, instrument handling), and timed procedural (sinus object retrieval) skills, confidence, and instructability via fellow-guided frontal balloon placement.

Results

Participants included 16 males (72.7%) and 6 females (27.3%). Intervention and control groups contained 10 (45.4%) and 12 (54.6%) students, respectively. Intervention group final “Total Psychomotor” scores were higher (10.1/15 vs 7.8/15, P = .0231). “Surgical confidence” was 3.3/5 versus 2.5/5, and “Instructability” was 3.9/5 versus 3.4/5 in intervention versus control groups, respectively ( P < .050). Multivariate regression analysis demonstrated superior psychomotor skills, navigation, and confidence in the intervention group ( P < .036). Activity perception scores were higher in intervention students versus controls, 26.13 versus 18.36/40 ( P = .022).

Conclusion

In surgical novices, endoscopic simulation leads to superior endoscopic navigation and task performance in cadavers. This simulation presents a novel method for incorporating Otolaryngology simulation in medical student education.

Phenomenological tissue fracture modeling for an Endoscopic Sinus and Skull Base Surgery training system based on experimental data

The ideal simulator for Endoscopic Sinus and Skull Base Surgery (ESSS) training must be supported by a physical model and provide repetitive behavior in a controlled environment. Development of realistic tissue models is a key part of ESSS virtual reality (VR)-based surgical simulation. Considerable research has been conducted to address haptic or force feedback and propose a phenomenological tissue fracture model for sino-nasal tissue during surgical tool indentation. Mechanical properties of specific sino-nasal regions of the sheep head have been studied in various indentation and relaxation experiments. Tool insertion at different indentation rates into coronal orbital floor (COF) tissue is modeled as a sequence of three events: deformation, fracture, and cutting. The behavior in the deformation phase can be characterized using a non-linear, rate-dependent modified Kelvin-Voigt model. A non-linear model for tissue behavior prior to the fracture point is presented. The overall model shows a non-positive dependency of maximum force on tool indentation rate, which indicates faster tool insertion velocity decreases the maximum final fracture force. The tissue cutting phase has been modeled to characterize the force necessary to slice through the COF. The proposed model in this study can help develop VR-based ESSS base simulators in otolaryngology and ophthalmology surgeries. Such simulators are useful in preoperative planning, accurate surgical simulation, intelligent robotic assistance, and treatment applications.

Immersive virtual reality as a teaching tool for neuroanatomy

BACKGROUND

Three-dimensional (3D) computer modeling and interactive virtual reality (VR) simulation are validated teaching techniques used throughout medical disciplines. Little objective data exists supporting its use in teaching clinical anatomy. Learner motivation is thought to limit the rate of utilization of such novel technologies. The purpose of this study is to evaluate the effectiveness, satisfaction, and motivation associated with immersive VR simulation in teaching medical students neuroanatomy.

METHODS

Images of normal cerebral anatomy were reconstructed from human Digital Imaging and Communications in Medicine (DICOM) computed tomography (CT) imaging and magnetic resonance imaging (MRI) into 3D VR formats compatible with the Oculus Rift VR System, a head-mounted display with tracking capabilities allowing for an immersive VR experience. The ventricular system and cerebral vasculature were highlighted and labeled to create a focused interactive model. We conducted a randomized controlled study with 66 medical students (33 in both the control and experimental groups). Pertinent neuroanatomical structures were studied using either online textbooks or the VR interactive model, respectively. We then evaluated the students' anatomy knowledge, educational experience, and motivation (using the Instructional Materials Motivation Survey [IMMS], a previously validated assessment).

RESULTS

There was no significant difference in anatomy knowledge between the 2 groups on preintervention, postintervention, or retention quizzes. The VR group found the learning experience to be significantly more engaging, enjoyable, and useful (all p < 0.01) and scored significantly higher on the motivation assessment (p < 0.01).

CONCLUSION

Immersive VR educational tools awarded a more positive learner experience and enhanced student motivation. However, the technology was equally as effective as the traditional text books in teaching neuroanatomy.

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.

Perceptual Assessment of Velopharyngeal Dysfunction by Otolaryngology Residents

OBJECTIVE

To assess the ability of otolaryngology residents to rate the hypernasal resonance of patients with velopharyngeal dysfunction. We hypothesize that experience (postgraduate year [PGY] level) and training will result in improved ratings of speech samples.

STUDY DESIGN

Prospective cohort study.

SETTING

Otolaryngology training programs at 2 academic medical centers.

SUBJECTS AND METHODS

Thirty otolaryngology residents (PGY 1-5) were enrolled in the study. All residents rated 30 speech samples at 2 separate times. Half the residents completed a training module between the rating exercises, with the other half serving as a control group. Percentage agreement with the expert rating of each speech sample and intrarater reliability were calculated for each resident. Analysis of covariance was used to model accuracy at session 2.

RESULTS

The median percentage agreement at session 1 was 53.3% for all residents. At the second session, the median scores were 53.3% for the control group and 60% for the training group, but this difference was not statistically significant. Intrarater reliability was moderate for both groups. Residents were more accurate in their ratings of normal and severely hypernasal speech. There was no correlation between rating accuracy and PGY level. Score at session 1 positively correlated with score at session 2.

CONCLUSION

Perceptual training of otolaryngology residents has the potential to improve their ratings of hypernasal speech. Length of time in residency may not be best predictor of perceptual skill. Training modalities incorporating practice with hypernasal speech samples could improve rater skills and should be studied more extensively.

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.

Development of the McGill simulator for endoscopic sinus surgery: a new high-fidelity virtual reality simulator for endoscopic sinus surgery

BACKGROUND

The technical challenges of endoscopic sinus surgery (ESS) and the high risk of complications support the development of alternative modalities to train residents in these procedures. Virtual reality simulation is becoming a useful tool for training the skills necessary for minimally invasive surgery; however, there are currently no ESS virtual reality simulators available with valid evidence supporting their use in resident education. Our aim was to develop a new rhinology simulator, as well as to define potential performance metrics for trainee assessment.

METHODS

The McGill simulator for endoscopic sinus surgery (MSESS), a new sinus surgery virtual reality simulator with haptic feedback, was developed (a collaboration between the McGill University Department of Otolaryngology-Head and Neck Surgery, the Montreal Neurologic Institute Simulation Lab, and the National Research Council of Canada). A panel of experts in education, performance assessment, rhinology, and skull base surgery convened to identify core technical abilities that would need to be taught by the simulator, as well as performance metrics to be developed and captured.

RESULTS

The MSESS allows the user to perform basic sinus surgery skills, such as an ethmoidectomy and sphenoidotomy, through the use of endoscopic tools in a virtual nasal model. The performance metrics were developed by an expert panel and include measurements of safety, quality, and efficiency of the procedure.

CONCLUSION

The MSESS incorporates novel technological advancements to create a realistic platform for trainees. To our knowledge, this is the first simulator to combine novel tools such as the endonasal wash and elaborate anatomic deformity with advanced performance metrics for ESS.

Use of Virtual Reality Tools for Vestibular Disorders Rehabilitation: A Comprehensive Analysis

Classical peripheral vestibular disorders rehabilitation is a long and costly process. While virtual reality settings have been repeatedly suggested to represent possible tools to help the rehabilitation process, no systematic study had been conducted so far. We systematically reviewed the current literature to analyze the published protocols documenting the use of virtual reality settings for peripheral vestibular disorders rehabilitation. There is an important diversity of settings and protocols involving virtual reality settings for the treatment of this pathology. Evaluation of the symptoms is often not standardized. However, our results unveil a clear effect of virtual reality settings-based rehabilitation of the patients' symptoms, assessed by objectives tools such as the DHI (mean decrease of 27 points), changing symptoms handicap perception from moderate to mild impact on life. Furthermore, we detected a relationship between the duration of the exposure to virtual reality environments and the magnitude of the therapeutic effects, suggesting that virtual reality treatments should last at least 150 minutes of cumulated exposure to ensure positive outcomes. Virtual reality offers a pleasant and safe environment for the patient. Future studies should standardize evaluation tools, document putative side effects further, compare virtual reality to conventional physical therapy, and evaluate economical costs/benefits of such strategies.

Comparison of cadaveric and isomorphic virtual haptic simulation in temporal bone training

Background

Virtual surgery may improve learning and provides an opportunity for pre-operative surgical rehearsal. We describe a novel haptic temporal bone simulator specifically developed for multicore processing and improved visual realism. A position locking algorithm for enhanced drill-bone interaction and haptic fidelity is further employed. The simulation construct is evaluated against cadaveric education.

Methods

A voxel-based simulator was designed for multicore architecture employing Marching Cubes and Laplacian smoothing to perform real-time haptic and graphic rendering of virtual bone.

Ten Otolaryngology trainees dissected a cadaveric temporal bone (CTB) followed by a virtual isomorphic haptic model (VM) based on derivative microCT data. Participants rated 1) physical characteristics, 2) specific anatomic constructs, 3) usefulness in skill development and 4) perceived educational value. The survey instrument employed a Likert scale (1-7).

Results

Residents were equivocal about the physical properties of the VM, as cortical (3.2 ± 2.0) and trabecular (2.8 ± 1.6) bone drilling character was appraised as dissimilar to CTB. Overall similarity to cadaveric training was moderate (3.5 ± 1.8). Residents generally felt the VM was beneficial in skill development, rating it highest for translabyrinthine skull-base approaches (5.2 ± 1.3). The VM was considered an effective (5.4 ± 1.5) and accurate (5.7 ± 1.4) training tool which should be integrated into resident education (5.5 ± 1.4). The VM was thought to improve performance (5.3 ± 1.8) and confidence (5.3 ± 1.9) and was highly rated for anatomic learning (6.1 ± 1.9).

Conclusion

Study participants found the VM to be a beneficial and effective platform for learning temporal bone anatomy and surgical techniques. They identify some concern with limited physical realism likely owing to the haptic device interface. This study is the first to compare isomorphic simulation in education. This significantly removes possible confounding features as the haptic simulation was based on derivative imaging.

Gesture-controlled interactive three dimensional anatomy: a novel teaching tool in head and neck surgery

Background

There is a need for innovative anatomic teaching tools. This paper describes a three dimensional (3D) tool employing the Microsoft Kinect™. Using this instrument, 3D temporal bone anatomy can be manipulated with the use of hand gestures, in the absence of mouse or keyboard.

Methods

CT Temporal bone data is imported into an image processing program and segmented. This information is then exported in polygonal mesh format to an in-house designed 3D graphics engine with an integrated Microsoft Kinect™. Motion in the virtual environment is controlled by tracking hand position relative to the user’s left shoulder.

Results

The tool successfully tracked scene depth and user joint locations. This permitted gesture-based control over the entire 3D environment. Stereoscopy was deemed appropriate with significant object projection, while still maintaining the operator’s ability to resolve image details. Specific anatomical structures can be selected from within the larger virtual environment. These structures can be extracted and rotated at the discretion of the user. Voice command employing the Kinect’s™ intrinsic speech library was also implemented, but is easily confounded by environmental noise.

Conclusion

There is a need for the development of virtual anatomy models to complement traditional education. Initial development is time intensive. Nonetheless, our novel gesture-controlled interactive 3D model of the temporal bone represents a promising interactive teaching tool utilizing a novel interface.

Construct validity of the ovine model in endoscopic sinus surgery training

OBJECTIVES/HYPOTHESIS

To demonstrate construct validity of the ovine model as a tool for training in endoscopic sinus surgery (ESS).

STUDY DESIGN

Prospective, cross-sectional evaluation study.

METHODS

Over 18 consecutive months, trainees and experts were evaluated in their ability to perform a range of tasks (based on previous face validation and descriptive studies conducted by the same group) relating to ESS on the sheep-head model. Anonymized randomized video recordings of the above were assessed by two independent and blinded assessors. A validated assessment tool utilizing a five-point Likert scale was employed. Construct validity was calculated by comparing scores across training levels and experts using mean and interquartile range of global and task-specific scores. Subgroup analysis of the intermediate group ascertained previous experience. Nonparametric descriptive statistics were used, and analysis was carried out using SPSS version 21 (IBM, Armonk, NY).

RESULTS

Reliability of the assessment tool was confirmed. The model discriminated well between different levels of expertise in global and task-specific scores. A positive correlation was noted between year in training and both global and task-specific scores (P < .001). Experience of the intermediate group was variable, and the number of ESS procedures performed under supervision had the highest impact on performance.

CONCLUSIONS

This study describes an alternative model for ESS training and assessment. It is also the first to demonstrate construct validity of the sheep-head model for ESS training.

Evaluation of a temporal bone prototype by experts in otology

BACKGROUND

Inexperienced otologists require training on the temporal bone drilling process, prior to any surgical activity. The shortage of cadaveric temporal bones exerts pressure to create realistic physical prototypes. This paper describes the evaluation by otology experts of a specially developed temporal bone resin model.

METHODS

Computed tomography images were transformed into digital files, and anatomically identical right temporal bone models were created using stereolithography. These hand-painted resin prototypes were sent to 25 otologists, accompanied by a 20-item questionnaire.

RESULTS

Satisfaction rate was 92 per cent. The overall prototype score was 48.87 out of 60. Average scores were: 12.63 out of 15 for anatomy-morphology, 6.98 out of 9 for quality of drilling, 16.74 out of 21 for identification of anatomical elements and 7.41 out of 9 for stages of drilling. Limitations of the model included an excessively vivid facial nerve colour and difficulty in identifying the posterior semicircular canal. Disadvantages related to the thickness of the resin and its residues were identified.

CONCLUSION

The prototype appears to provide an attractive solution to the shortage of cadaveric temporal bones. However, interest in the model for drilling technique training for inexperienced otologists has not yet been assessed.

Three-dimensional sinus imaging as an adjunct to two-dimensional imaging to accelerate education and improve spatial orientation

OBJECTIVES/HYPOTHESIS

Develop a novel three-dimensional (3-D) anatomical model to assist in improving spatial knowledge of the skull base, paranasal sinuses, and adjacent structures, and validate the utilization of 3-D reconstruction to augment two-dimensional (2-D) computed tomography (CT) for the training of medical students and otolaryngology-head and neck surgery residents.

STUDY DESIGN

Prospective study.

METHODS

A study of 18 subjects studying sinus anatomy was conducted at a tertiary academic center during the 2011 to 2012 academic year. An image processing and 3-D modeling program was used to create a color coded 3-D scalable/layerable/rotatable model of key paranasal and skull base structures from a 2-D high-resolution sinus CT scan. Subjects received instruction of the sinus anatomy in two sessions, first through review of a 2-D CT sinus scan, followed by an educational module of the 3-D reconstruction. After each session, subjects rated their knowledge of the sinus and adjacent structures on a self-assessment questionnaire.

RESULTS

Significant improvement in the perceived understanding of the anatomy was noted after the 3-D educational module session when compared to the 2-D CT session alone (P < .01). Every subject believed the addition of 3-D imaging accelerated their education of sinus anatomy and recommended its use to others.

CONCLUSIONS

The impression of the learners was that a 3-D educational module, highlighting key structures, is a highly effective tool to enhance the education of medical students and otolaryngology residents in sinus and skull base anatomy and its adjacent structures, specifically in conceptualizing the spatial orientation of these structures.

Preliminarily measurement and analysis of sawing forces in fresh cadaver mandible using reciprocating saw for reality-based haptic feedback

PURPOSE

The aim of the study was to preliminarily measure and analyze the cutting forces in fresh Chinese cadaver mandible using a clinically widely used reciprocating saw for reality-based haptic feedback.

METHODS

Eight mandibles were taken from fresh Chinese cadavers, 4 females and 4 males, aged between 59 and 95 years. A set of sawing experiments, using a surgery Stryker micro-reciprocating saw and Kistler piezoelectric dynamometer, was carried out by a CNC machining center. Under different vibration frequencies of saw and feeding rates measured from orthognathic surgery, sawing forces were recorded by a signal acquisition system.

RESULTS

Remarkably different sawing forces were measured from different cadavers. Feed and vibration frequency of the reciprocating saw could determine the cutting forces only on 1 body. To reduce the impact of bone thickness changes on the cutting force measurements, all the cutting force data should be converted to the force of unit cutting length. The vibration frequency of haptic feedback system is determined by main cutting forces. Fast Fourier transform method can be used to calculate the frequency of this system. To simulate surgery in higher fidelity, all the sawing forces from the experiment should be amended by experienced surgeons before use in virtual reality surgery simulator.

CONCLUSIONS

Sawing force signals of different ages for force feedback were measured successfully, and more factors related to the bone mechanical properties, such as bone density, should be concerned in the future.

A Systematic Review of Simulators in Otolaryngology

Objective

To conduct a systematic review of published articles that describe simulators that could be used in otolaryngology for education, skill acquisition, and/or skill improvement.

Data Sources

Ovid and Embase databases searched July 14, 2011.

Review Methods

Three hundred fifty-three abstracts were independently reviewed by both authors, then 154 eligible articles were reviewed by both authors, and 95 articles were categorized by organ system (eg, otologic); type of simulator (eg, physical, virtual); whether the simulator was a prototype, could be purchased, or was constructed; validation; and level of learning assessment. Discrepancies were resolved by re-review and discussion.

Results

In addition to 11 overview articles, 28 articles described 16 otology simulators, most of which are virtual and prototypes. Ninteen articles described 10 sinus/rhinology simulators; most are virtual surgery simulators and prototypes. Eight articles described 8 oral cavity simulators, and 8 articles described neck simulators. Seventeen articles described 13 bronchoscopy simulators; several are full-body high-technology manikins adapted from other purposes. Five articles described eclectic simulators, including some for learning nontechnical and teamwork skills. Half of the simulators have been validated. Learning levels were often not assessed or assessment was limited to the learners’ perceptions.

Conclusion

A wide variety of simulators are available or under development. Lack of unified validation concepts and limited descriptions restricted our ability to assess model characteristics, availability, and validation. Simulators are emerging as powerful tools to facilitate learning; this review may provide a platform for discussion and refinement of the information reported and analyzed in evaluating simulators.

Individual models for virtual bone drilling in mastoid surgery

Segmented training cases for virtual simulation of bone-drilling interventions in middle ear surgery have proven to be helpful in learning about surgical anatomy of the temporal bone. The anatomy of the mastoid shows a high degree of variability, however, and the aim of this study was to evaluate whether individual virtual models could be created within an affordable timeframe, and to what extend they reflected natural individual anatomy during virtual mastoid surgery. Automatic segmentation schemes were used, and these reduced the time required to create individual models on the basis of DICOM CT scans to less than 5 minutes. Models based on CT data with a slice distance of 0.4 mm or better were found to provide excellent handling, an acceptable depiction of mastoidal organs, and a helpful impression of the individual surgical situation. Although landmarks are still more easily detected in real mastoids, virtual drilling of individual models makes the 3D estimation of specific anatomy more effective than estimations based on interpretation of CT scans alone.

Improving temporal bone dissection using self-directed virtual reality simulation: results of a randomized blinded control trial

OBJECTIVE

A significant benefit of virtual reality (VR) simulation is the ability to provide self-direct learning for trainees. This study aims to determine whether there are any differences in performance of cadaver temporal bone dissections between novices who received traditional teaching methods and those who received unsupervised self-directed learning in a VR temporal bone simulator.

STUDY DESIGN

Randomized blinded control trial.

SETTING

Royal Victorian Eye and Ear Hospital.

SUBJECTS

Twenty novice trainees.

METHODS

After receiving an hour lecture, participants were randomized into 2 groups to receive an additional 2 hours of training via traditional teaching methods or self-directed learning using a VR simulator with automated guidance. The simulation environment presented participants with structured training tasks, which were accompanied by real-time computer-generated feedback as well as real operative videos and photos. After the training, trainees were asked to perform a cortical mastoidectomy on a cadaveric temporal bone. The dissection was videotaped and assessed by 3 otologists blinded to participants' teaching group.

RESULTS

The overall performance scores of the simulator-based training group were significantly higher than those of the traditional training group (67% vs 29%; P < .001), with an intraclass correlation coefficient of 0.93, indicating excellent interrater reliability. Using other assessments of performance, such as injury size, the VR simulator-based training group also performed better than the traditional group.

CONCLUSIONS

This study indicates that self-directed learning on VR simulators can be used to improve performance on cadaver dissection in novice trainees compared with traditional teaching methods alone.

Assessing mental representation of mastoidectomy by a computer-based drawing tool

CONCLUSIONS

This simple computer-based drawing tool provides valid information on mental representation of mastoidectomy at its initial phase.

OBJECTIVE

The aim of this study was to elaborate a simple computer-based drawing tool to assess the mental representation of mastoidectomy.

METHODS

Twelve trainees in otology (five beginners, seven mid-level) and four otology experts participated in this prospective study. The image of a mastoid was displayed on a screen. All subjects reproduced the movements of mastoidectomy with a pen on a graphic tablet. Movements appeared as gray lines on the image. Surgeons were evaluated before and after a dissection course. The surface of mastoidectomy, perimeter, circularity, and the angle between traces and cavity edges were measured by Image J software.

RESULTS

The total surface of mastoidectomy was higher in experts than in mid-level and beginner trainees (respectively 99 ± 6.5%, vs 57 ± 1.5%, and 22 ± 5.6%, p < 0.01 for experts vs beginners and p < 0.05 for experts vs mid-level, ANOVA and Bonferroni). Circularity was also higher in experts than in trainees. After training, total surface and circularity increased. The angle between traces and cavity edges was lower in experts than in trainees and was reduced after training.

Assessment of microvascular anastomosis training in otolaryngology residencies: Survey of United States program directors

OBJECTIVE

To assess current microvascular training strategies in otolaryngology residency programs.

STUDY DESIGN

Cross-sectional study.

SETTING

U.S. otolaryngology residency programs.

SUBJECTS AND METHODS

A total of 104 U.S. otolaryngology program directors received surveys inquiring about program size, the presence of fellowship training in microvascular surgery, the number of microvascular cases per month, the use of microvascular animal laboratory, and whether residents, fellows, or co-attendings assist in the anastomoses.

RESULTS

A 51 percent response rate was achieved, and of the 54 programs that responded, 78 percent reported no microvascular fellowship positions in plastics or head and neck reconstruction. A total of 52 percent reported performing three or fewer microvascular surgeries per month. Of the programs that did not have a microvascular fellow, only five (12%) performed eight or more surgeries per month. A total of 65 percent of the programs reported that residents assist during the anastomosis at least 75 percent of the time. Of the programs where residents assist 75 percent or more of the time, 70 percent have a formal training in microvascular technique ranging from demonstrating laboratory competencies to multiday courses. A total of 48 percent of the responding programs report having an animal laboratory for microvascular surgery. All animal laboratories used the rat as the model.

CONCLUSION

Many programs find value in providing residents with microvascular training, both in the operating room and in the laboratory. Only a small minority of programs without fellowship positions responded that they perform microvascular surgery on a regular basis (4 or more surgeries per month).

Differentiating levels of surgical experience on a virtual reality temporal bone simulator

Objective

Virtual reality simulation is increasingly being incorporated into surgical training and may have a role in temporal bone surgical education. Here we test whether metrics generated by a virtual reality surgical simulation can differentiate between three levels of experience, namely novices, otolaryngology residents, and experienced qualified surgeons.

Study Design

Cohort study.

Setting

Royal Victorian Eye and Ear Hospital.

Subjects and Methods

Twenty-seven participants were recruited. There were 12 experts, six residents, and nine novices. After orientation, participants were asked to perform a modified radical mastoidectomy on the simulator. Comparisons of time taken, injury to structures, and forces exerted were made between the groups to determine which specific metrics would discriminate experience levels.

Results

Experts completed the simulated task in significantly shorter time than the other two groups (experts 22 minutes, residents 36 minutes, and novices 46 minutes; P = 0.001). Novices exerted significantly higher average forces when dissecting close to vital structures compared with experts (0.24 Newton [N] vs 0.13 N, P = 0.002). Novices were also more likely to injure structures such as dura compared to experts (23 injuries vs 3 injuries, P = 0.001). Compared with residents, the experts modulated their force between initial cortex dissection and dissection close to vital structures. Using the combination of these metrics, we were able to correctly classify the participants’ level of experience 90 percent of the time.

Conclusion

This preliminary study shows that measurements of performance obtained from within a virtual reality simulator can differentiate between levels of users’ experience. These results suggest that simulator training may have a role in temporal bone training beyond foundational training.

Three-dimensional modeling of the temporal bone for surgical training

INTRODUCTION

The anatomy of the temporal bone (TB) can only be mastered by repeated surgical and anatomic dissections, and surgical teaching initiative had a major effect on outcomes. The aim of this study was to investigate the validity of an artificial TB model devoted to surgical training and education.

MATERIALS AND METHODS

A helical computed tomographic (CT) scan was used to acquire high-resolution data of cadaveric TB. Digital imaging and communications in medicine (DICOM) data were converted into.stl files after data processing. Cadaveric TBs were prototyped using stereolithography. The validation of the prototype needed several steps. First of all, we have studied on CT scan the positional relationship between the facial nerve and other structures of the cadaveric TBs and prototyped bones. Otoendoscopy of the middle ear and the internal acoustic canal and visualization of anatomic landmarks during TB drilling of the cadaveric TBs and prototyped bones were also performed.

RESULTS

Seven normal CT scans of cadaveric TB were selected to make prototyped bone using stereolithography. Measurements of volume and distance showed no significant difference between prototypes and cadaver TBs. Classic mastoid surgical procedures were performed in the Anatomy Department: exposing sigmoid sinus, facial nerve, labyrinth, dura mater, jugular bulb, and internal carotid artery. Two simulations of implantable middle ear prosthesis were made successfully.

CONCLUSION

These prototypes made using stereolithography seem to be a good anatomic model for surgical training. This model could also be interesting for surgical planning in congenital ear anomalies before middle ear prosthesis implantation.

Virtual reality: a new paranasal sinus surgery simulator

OBJECTIVES/HYPOTHESIS

Virtual surgical training systems are of growing value. Current prototypes for endonasal sinus surgery simulation are very expensive or lack running stability. No reliable system is available to a notable number of users yet. The purpose of this work was to develop a dependable simulator running on standard PC hardware including a detailed anatomic model, realistic tools and handling, stereoscopic view, and force feedback.

STUDY DESIGN

Descriptive.

METHODS

A three-dimensional voxel model was created based on a high-resolution computed tomography study of a human skull, from which the bony structures were segmented. The mucosa and organs at risk were added manually. The model may be manipulated with virtual surgical tools controlled with a low-cost haptic device, which is also used to adjust microscopic or endoscopic views. Visualization, haptic rendering, and tissue removal are represented with subvoxel resolution.

RESULTS

The handling of the model is convincing. The haptic device provides a realistic feeling regarding the interaction between tool tip and anatomy. Three-dimensional orientation and the look and feel of virtual surgical interventions get close to reality.

CONCLUSIONS

The newly developed system is a stable, fully operational simulator for sinus surgery based on standard PC hardware. Besides the limitations of a low-cost haptic device, the presented system is highly realistic regarding anatomy, visualization, manipulation, and the appearance of the tools. It is mainly intended for gaining surgical anatomy knowledge and for training navigation in a complex anatomical environment. Learning effects, including motor skills, have yet to be quantified.

Enhancement of temporal bone anatomy learning with computer 3D rendered imaging software

AIM

To determine whether the use of 3D anatomical models is helpful to students and enhances their anatomical knowledge.

METHODS

First year undergraduate students on the speech therapy or hearing aid practitioner courses attended either a lecture alone or a lecture followed by a 3D anatomy based tutorial, the latter which was also attended by ENT residents. Participants who received the tutorial were free to use the 3D model on the university computers or on their home computer and were then asked to answer a satisfaction questionnaire. At the end of the first year examinations, the grades of the undergraduate students were compared between the lecture alone group and lecture plus tutorial group.

RESULTS

Generally, all participants found this new tool interesting and user-friendly for the learning of temporal bone anatomy. However, most also considered the help of a teacher indispensable to guide them through the virtual dissection. First year undergraduate students who received the 3D anatomy tutorial performed significantly better during their end of year examination compared to those receiving a lecture alone, particularly concerning the more difficult questions.

CONCLUSION

The 3D anatomical software, used in parallel with traditional teaching methods, such as lectures and cadaver dissection, appears to be a promising tool to improve student learning of temporal bone anatomy.

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

Objective:

We aimed to review the history of anatomical dissection, and to examine how modern educational techniques will change the way temporal bone dissection is taught to otolaryngology trainees.

Method:

Review of the literature using Medline, Embase and PubMed database searches.

Results:

Temporal bone anatomy has traditionally been taught using cadaveric specimens. However, resources such as three-dimensional reconstructed models and ‘virtual reality’ temporal bone simulators have a place in educating the otolaryngology trainee.

Conclusion:

We should encourage the use of fresh frozen cadaveric temporal bone specimens for future otologists. Artificial three-dimensional models and virtual reality temporal bone simulators can be used to educate junior trainees, thus conserving the scarce resource of cadaveric bones.

Integration of patient-specific paranasal sinus computed tomographic data into a virtual surgical environment

BACKGROUND

The advent of both high-resolution computed tomographic (CT) imaging and minimally invasive endoscopic techniques has led to revolutionary advances in sinus surgery. However, the rhinologist is left to make the conceptual jump between static cross-sectional images and the anatomy encountered intraoperatively. A three-dimensional (3D) visuo-haptic representation of the patient's anatomy may allow for enhanced preoperative planning and rehearsal, with the goal of improving outcomes, decreasing complications, and enhancing technical skills.

METHODS

We developed a novel method of automatically constructing 3D visuo-haptic models of patients' anatomy from preoperative CT scans for placement in a virtual surgical environment (VSE). State-of-the-art techniques were used to create a high-fidelity representation of salient bone and soft tissue anatomy and to enable manipulation of the virtual patient in a surgically meaningful manner. A modified haptic interface device drives a virtual endoscope that mimics the surgical configuration.

RESULTS

The creation and manipulation of sinus anatomy from CT data appeared to provide a relevant means of exploring patient-specific anatomy. Unlike more traditional methods of interacting with multiplanar imaging data, our VSE provides the potential for a more intuitive experience that can replicate the views and access expected at surgery. The inclusion of tactile (haptic) feedback provides an additional dimension of realism.

CONCLUSION

The incorporation of patient-specific clinical CT data into a virtual surgical environment holds the potential to offer the surgeon a novel means to prepare for rhinologic procedures and offer training to residents. An automated pathway for segmentation, reconstruction, and an intuitive interface for manipulation may enable rehearsal of planned procedures.

Does preoperative analysis of intrahepatic venous anastomoses improve the surgeon's intraoperative decision making? Pilot data from a case report

Background

Three-dimensional (3D) visualization is thought to improve the anatomical understanding of clinicians, thus improving patient safety.

Case presentation

A 58-year-old male was admitted to our hospital in April 2007 with a suspected metastasis of a sigmoid cancer in the Couinaud segment (CS) 7. The anatomical situation of this patient was analyzed using both a CT scan and 3D images. The initial CT scan revealed that the proximal part of the middle hepatic vein was completely missing and the metastasis in the CS 7 was closely attached to the right hepatic vein. After analyzing additional 3D images, it became clear that due to the close proximity of metastasis and right hepatic vein, the resection of the right hepatic vein was inevitable. Based on this 3D analysis, it was decided to perform a right-sided hemihepatectomy. In this case report, 3D visualization resulted in a faster and clearer understanding of the unique anatomical situation in a patient with complicated liver anatomy than transversal CT images.

Conclusion

The here presented data shows for the first time 3D visualization of intravenous anastomoses in the human liver. The information offered by 3D visualization is not redundant but rather serves as a true source of additional information, indicating the potential benefit of 3D visualization in surgical operation planning.

The coblation tonsillectomy learning curve

OBJECTIVE

To establish if there is a learning curve for coblation tonsillectomy.

STUDY DESIGN

Regression analysis of data obtained from surgeons identified from the Australian Tonsillectomy Survey.

SUBJECTS AND METHODS

Thirty otolaryngologists were invited to contribute audit data. Data were stratified into groups of 10 procedures and analysed with regression analysis.

RESULTS

Nineteen (70%) surgeons responded. Complete data were obtained for 1700 cases and return to theatre data on 2062 cases. There was a significant learning curve with respect to both primary (P = 0.050) and secondary (P = 0.028) hemorrhage rates. Mean rates were 0.3% (95% CI 0.1% to 0.7%) and 2.1% (95% CI 1.5% to 2.9%) for primary and secondary bleeds, respectively, with return to theatre in 0.2% (95% CI 0.1% to 0.5%) and 1.3% (95% CI 0.9% to 1.9%), respectively.

CONCLUSION

The introduction of coblation tonsillectomy into Australia was associated with a statistically significant learning curve with respect to both primary and secondary hemorrhage rates.