Mastoidectomy Performance Research Articles

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

PurposeThe opportunities for surgical training and practice in the operating room are in decline due to limited resources, increased efficiency demands, growing complexity of the cases, and concerns for patient safety. Virtual reality (VR) offers a novel opportunity to enhance surgical training and provide complementary three-dimensional experience that has been usually available in the operating room. Since VR allows viewing and manipulation of realistic 3D models, the VR environment could enhance anatomical and topographical knowledge, in particular. In this study, we explored whether incorporating VR anatomy training improves novices’ performance during mastoidectomy over traditional methods.MethodsThirty medical students were randomized into two groups and taught mastoidectomy in a structured manner. One group utilized a VR temporal bone model during the training while the other group used more traditional materials such as anatomy books. After the training, all participants completed a mastoidectomy on a 3D-printed temporal bone model under expert supervision. Performance during the mastoidectomy was evaluated with multiple metrics and feedback regarding the two training methods was gathered from the participants.ResultsThe VR training method was rated better by the participants, and they also needed less guidance during the mastoidectomy. There were no significant differences in operational time, the occurrence of injuries, self-assessment scores, and the surgical outcome between the two groups.ConclusionOur results support the utilization of VR training in complete novices as it has higher trainee satisfaction and leads to at least as good results as the more traditional methods.

Mastoidectomy Training: Is Anatomical Variation Needed? A Randomized, Controlled Trial on Performance and Skills Transfer From Virtual Reality to a Three-Dimensional Printed Model.

Virtual reality (VR) simulation-based training effectively improves novices' mastoidectomy skills. Unfortunately, learning plateaus at an insufficient level and knowledge on optimizing mastoidectomy training to overcome this plateau is needed. In this study, we aim to investigate how training on anatomically different temporal bone cases affects learning, including the effect on retention and transfer of skills. Randomized controlled trial of an educational intervention. The Simulation Center at Copenhagen Academy for Medical Education and Simulation. Twenty-four medical students from the University of Copenhagen. Participants were randomized to practice mastoidectomy on either 12 anatomically varying (intervention group) or 12 identical (control group) cases in a VR simulator. At the end of training and again ~ 3 weeks after training (retention), learners were tested on a new VR patient case and a three-dimensional printed model. Mastoidectomy performance evaluated by blinded expert raters using a 26-item modified Welling Scale. The intervention and control groups' performance results were comparable at the end of training. Likewise, retention and transfer performances were similar between groups. The overall mean score at the end of training corresponded to approximately 70% of the possible maximum score. Simulation-based training using anatomical variation was equivalent to training on a single case with respect to acquisition, retention, and transfer of mastoidectomy skills. This suggests that efforts to expose novices to variation during initial training are unnecessary as this variation has limited effect, and-conversely-that educators can expose novices to naturally different anatomical variations without worry of hindered learning.

Real-time synchronized recording of force and position data during a mastoidectomy – Toward robotic mastoidectomy development

BackgroundRobotics is currently being adopted across the spectrum of neurosurgery from deep brain stimulation to spine surgery instrumentation. Mastoidectomy is a cognitively demanding procedure that involves careful removal of bone around the critical structures of the temporal bone. Herein, we report a pilot study that serves as a proof of concept for real-time, multiparameter recording during mastoidectomy. MethodsThis pilot study involved the iterative development of a platform for the real time recording of video, 3D position, velocity, acceleration, and force data during the performance of mastoidectomy using cadaveric specimens. ResultsAcross all 8 replicates, the average distance traveled by the drill tip in the x, y, and z axes was 39.88 mm (±11.98 mm), 38.52 mm (±8.24 mm), 31.40 mm (±7.89 mm), respectively. The overall average ranges for velocity and acceleration of the drill tip in the x axis were 412.81 mm/s (±91.12 mm/s) and 6383.05 mm/s2 (±941.05 mm/s2). The range of forces recorded was 8.52 N (±2.90 N), 40.94 N (±9.81 N), and 35.42 N (±11.06 N) in the x-, y-, and z-axis, respectively. ConclusionsThis study represents a proof-of-concept that the mechanical parameters associated with surgeon-performed mastoidectomy can be recorded in real-time. This represents a crucial step in understanding the human drilling process which incorporates visual and haptic sensory input with experiential and explicit knowledge using fuzzy logic feedback. Ultimately, data collected using this methodology may provide the groundwork for the development of an algorithm for robotic mastoidectomy.

Endoscopic Over Under Cartilage Tympanoplasty Is Not Inferior to Underlay Cartilage Tympanoplasty.

Evaluate whether elevating the tympanic membrane from the malleus during endoscopic tympanoplasty may negatively affect postoperative hearing outcomes or perforation rates by comparing 2 similar endoscopic tympanoplasty techniques. Retrospective cohort. Tertiary care center. Endoscopic over-under cartilage tympanoplasties age and gender matched to endoscopic underlay cartilage tympanoplasties between January 2015 and January 2019. Exclusion criteria included preoperative or intraoperative cholesteatoma, performance of mastoidectomy or ossicular chain reconstruction, and lack of postoperative audiogram. Endoscopic cartilage tympanoplasty via over-under or underlay technique. Pre- and postoperative pure-tone average and word recognition score, graft success. A total of 52 patients were evaluated: 26 endoscopic over-under cartilage tympanoplasties were matched to endoscopic underlay cartilage tympanoplasties. Both groups demonstrated a statistically significant improvement in air conduction hearing (9 dB [P < 0.001] and 6 dB [P < 0.01], respectively), and bone pure-tone average did not worsen in either group (P < 0.001 and P < 0.05, respectively). Postoperative air conduction pure-tone average was statistically noninferior in the over-under group compared with the underlay group (P < 0.05). Reperforation was present in 3 patients (12%) in the underlay group and none in the over-under group, but this difference was not statistically significant (P = 0.24). Endoscopic over-under cartilage tympanoplasty effectively closes tympanic membrane perforations and improves hearing, without greater risk than underlay tympanoplasty. Elevating the tympanic membrane from the malleus does not confer worsen hearing outcomes.

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

ObjectiveMastoidectomy is a cornerstone in the surgical management of middle and inner ear diseases. Unfortunately, training is challenged by insufficient access to human cadavers. Three-dimensional (3D) printing of temporal bones could alleviate this problem, but evidence on their educational effectiveness is lacking. It is largely unknown whether training on 3D-printed temporal bones improves mastoidectomy performance, including on cadavers, and how this training compares with virtual reality (VR) simulation. To address this knowledge gap, this study investigated whether training on 3D-printed temporal bones improves cadaveric dissection performance, and it compared this training with the already-established VR simulation.Study DesignProspective cohort study of an educational intervention.SettingTertiary university hospital, cadaver dissection laboratory, and simulation center in Copenhagen, Denmark.MethodsEighteen otorhinolaryngology residents (intervention) attending the national temporal bone dissection course received 3 hours of mastoidectomy training on 3D-printed temporal bones. Posttraining cadaver mastoidectomy performances were rated by 3 experts using a validated assessment tool and compared with those of 66 previous course participants (control) who had received time-equivalent VR training prior to dissection.ResultsThe intervention cohort outperformed the controls during cadaver dissection by 29% (P < .001); their performances were largely similar across training modalities but remained at a modest level (~50% of the maximum score).ConclusionMastoidectomy skills improved from training on 3D-printed temporal bone and seemingly more so than on time-equivalent VR simulation. Importantly, these skills transferred to cadaveric dissection. Training on 3D-printed temporal bones can effectively supplement cadaver training when learning mastoidectomy.

Automated assessment of cortical mastoidectomy performance in virtual reality.

Cortical mastoidectomy is a core skill that Otolaryngology trainees must gain competency in. Automated competency assessments have the potential to reduce assessment subjectivity and bias, as well as reducing the workload for surgical trainers. This study aimed to develop and validate an automated competency assessment system for cortical mastoidectomy. Data from 60 participants (Group 1) were used to develop and validate an automated competency assessment system for cortical mastoidectomy. Data from 14 other participants (Group 2) were used to test the generalisability of the automated assessment. Participants drilled cortical mastoidectomies on a virtual reality temporal bone simulator. Procedures were graded by a blinded expert using the previously validated Melbourne Mastoidectomy Scale: a different expert assessed procedures by Groups 1 and 2. Using data from Group 1, simulator metrics were developed to map directly to the individual items of this scale. Metric value thresholds were calculated by comparing automated simulator metric values to expert scores. Binary scores per item were allocated using these thresholds. Validation was performed using random sub-sampling. The generalisability of the method was investigated by performing the automated assessment on mastoidectomies performed by Group 2, and correlating these with scores of a second blinded expert. The automated binary score compared with the expert score per item had an accuracy, sensitivity and specificity of 0.9450, 0.9547 and 0.9343, respectively, for Group 1; and 0.8614, 0.8579 and 0.8654, respectively, for Group 2. There was a strong correlation between the total scores per participant assigned by the expert and calculated by the automatic assessment method for both Group 1 (r=.9144, P<.0001) and Group 2 (r=.7224, P<.0001). This study outlines a virtual reality-based method of automated assessment of competency in cortical mastoidectomy, which proved comparable to the assessment provided by human experts.

Concurrent Nasal Surgery with Mastoidectomy in Adults

Objective: To compare our findings with published success rates for mastoidectomy performed withconcurrent nasal surgeryMaterials and Method: The study was conducted from May 2017 – September 2019 in the E.N.T departmentof Saraswathi Institute of Medical Sciences, Hapur. We retrospectively reviewed 35 consecutively presentingpatients who had undergone concurrent septoplasty and mastoidectomy with or without ossicular chainreconstruction. . The study consist of patients ranged in age from 18 to 50 years and were followed up for 1- 24 months. Surgical success was defined as presence of an intact TM graft ,well epithelized mastoid cavitywithout any evidence of middle ear effusion .Results: Our 2 primary finding – graft survival rate of 91.42% and an overall surgical success rate of 77.1% compare favourably with the results of other studies of outcomes of isolated mastoidectomies. Our dataindicates that simultaneous performance of nasal surgery and mastoidectomy is feasible in adults. Nasalpacking has got short term effect on ET dysfunction but rarely severe enough to cause symptoms or middleear effusion. Concurrent approach is useful in TM graft survival or mastoid cavity epithelisation in longterm overall surgical treatment success. The concurrent approach requires only single time administrationof general anaesthesia, cost effective treatment, improved overall symptomatic relief from nasal and earsymptoms.

Expert sampling of VR simulator metrics for automated assessment of mastoidectomy performance

Often the assessment of mastoidectomy performance requires time-consuming manual rating. Virtual reality (VR) simulators offer potentially useful automated assessment and feedback but should be supported by validity evidence. We aimed to investigate simulator metrics for automated assessment based on the expert performance approach, comparison with an established assessment tool, and the consequences of standard setting. The performances of 11 experienced otosurgeons and 37 otorhinolaryngology residents. Participants performed three mastoidectomies in the Visible Ear Simulator. Nine residents contributed additional data on repeated practice in the simulator. One hundred and twenty-nine different performance metrics were collected by the simulator and final-product files were saved. These final products were analyzed using a modified Welling Scale by two blinded raters. Seventeen metrics could discriminate between resident and experienced surgeons' performances. These metrics mainly expressed various aspects of efficiency: Experts demonstrated more goal-directed behavior and less hesitancy, used less time, and selected large and sharp burrs more often. The combined metrics-based score (MBS) demonstrated significant discriminative ability between experienced surgeons and residents with a mean difference of 16.4% (95% confidence interval [12.6-20.2], P << 0.001). A pass/fail score of 83.6% was established. The MBS correlated poorly with the final-product score but excellently with the final-product score per time. The MBS mainly reflected efficiency components of the mastoidectomy procedure, and although it could have some uses in self-directed training, it fails to measure and encourage safe routines. Supplemental approaches and feedback are therefore required in VR simulation training of mastoidectomy. 2b Laryngoscope, 129:2170-2177, 2019.

Performance metrics in mastoidectomy training: a systematic review.

To investigate validity evidence, and strengths and limitations of performance metrics in mastoidectomy training. A systematic review following the PRISMA guidelines. Studies reporting performance metrics in mastoidectomy/temporal bone surgery were included. Data on design, outcomes, and results were extracted by two reviewers. Validity evidence according to Messick's framework and level of evidence were assessed. The search yielded a total of 1085 studies from the years 1947-2018 and 35 studies were included for full data extraction after abstract and full-text screening. 33 different metrics on mastoidectomy performance were identified and ranked according to the number of reports. Most of the 33 metrics identified had some amount of validity evidence. The metrics with most validity evidence were related to drilling time, volume drilled per time, force applied near vital structures, and volume removed. This review provides an overview of current metrics of mastoidectomy performance, their validity, strengths and limitations, and identifies the gap in validity evidence of some metrics. Evidence-based metrics can be used for performance assessment in temporal bone surgery and for providing integrated and automated feedback in virtual reality simulation training. The use of such metrics in simulation-based mastoidectomy training can potentially address some of the limitations in current temporal bone skill assessment and ease assessment in repeated practice. However, at present, an automated feedback based on metrics in VR simulation does not have sufficient empirical basis and has not been generally accepted for use in training and certification. 2a.

The Effect of a Distributed Virtual Reality Simulation Training Program on Dissection Mastoidectomy Performance.

To investigate the effect on final-product performance of a distributed, virtual reality (VR) simulation training program on cadaveric dissection performance and learning curves compared with standard VR simulation training during a temporal bone course. Educational interventional cohort study. The national Danish temporal bone courses of 2016 and 2017. Postgraduate year 2 to 5 residents in otorhinolaryngology. Nine participants volunteered for additional VR simulation training (intervention) before the temporal bone course, with training blocks distributed (i.e., separated). The remaining 28 participants received standard VR simulation training during the temporal bone course (control). VR simulation and cadaveric dissection final-product performances were analyzed by blinded raters using a 26-item modified Welling Scale. Distributed VR simulation training before the temporal bone course (intervention) significantly increased dissection final-product performance by 25% compared with standard VR simulation training during the course (control) (mean scores 12.8 points versus 10.3 points, p < 0.01). Distributed and repeated VR simulation practice markedly decreased drilling time. Guidance by the simulator-integrated tutor-function significantly increased final-product performance by 2.3 points compared with nontutored procedures but at the cost of increased drilling time. Skills acquired in a VR simulation environment translate to cadaveric dissection skills and repeated and distributed VR simulation can be used to further increase performance compared with standard VR simulation training during a temporal bone course. Further dissemination of inexpensive VR simulators would allow all future temporal bone course participants to train locally before attending future centralized courses.

Multi-Institutional Development of a Mastoidectomy Performance Evaluation Instrument

A method for rating surgical performance of a mastoidectomy procedure that is shown to apply universally across teaching institutions has not yet been devised. This work describes the development of a rating instrument created from a multi-institutional consortium. Using a participatory design and a modified Delphi approach, a multi-institutional group of expert otologists constructed a 15-element task-based checklist for evaluating mastoidectomy performance. This instrument was further refined into a 14-element checklist focusing on the concept of safety after using it to rate a large and varied population of performances. Twelve otolaryngological surgical training programs in the United States. A total of 14 surgeons from 12 different institutions took part in the construction of the instrument. By using 14 experts from 12 different institutions and a literature review, individual metrics were identified, rated as to the level of importance and operationally defined to create a rating scale for mastoidectomy performance. Initial use of the rating scale showed modest rater agreement. The operational definitions of individual metrics were modified to emphasize "safe" as opposed to "proper" technique. A second rating instrument was developed based on this feedback. Using a consensus-building approach with multiple rounds of communication between experts is a feasible way to construct a rating instrument for mastoidectomy. Expert opinion alone using a Delphi method provides face and content validity evidence, however, this is not sufficient to develop a universally acceptable rating instrument. A continued process of development and experimentation to demonstrate evidence for reliability and validity making use of a large population of raters and performances is necessary to achieve universal acceptance.

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.

Factors influencing decision making among ENT surgeons on performance of cortical mastoidectomy for CSOM-tubotympanic disease in quiescent/active stage: an opinion based study

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; As the role of cortical mastoidectomy as an adjunct to tympanoplasty in the management of CSOM tubotympanic type - quiescent stage remains controversial even today; we intend to study the factors that influence the decision of ENT surgeons on whether or not to perform cortical mastoidectomy in patients with CSOM (chronic suppurative otitis media) - active or quiescent ear.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; During May to August 2016, 60 ENT surgeons within Chennai were asked to answer a pre-framed questionnaire on CSOM based on their personal surgical experience. The answers were collected by direct questionnaire method and the data subjected to appropriate statistical analysis.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; 65% surgeons expected a minimum dry ear period of ≤30 days before considering tympanoplasty alone (group 1) and the rest 35% members expected more than 30 days of dry ear period (group 2). Surgeons ≤40 years of age expected lesser duration of dry ear period prior to consideration of tympanoplasty alone (p =0.016). Group 2 surgeons performed cortical mastoidectomy in more number of cases (&amp;gt;50%) when compared to group 1 surgeons (p =0.03) for patients who presented first to them with a wet ear. There was a mixed opinion among surgeons within group 1 itself on whether or not they would do cortical mastoidectomy when they encountered patients who had congested remnant tympanic membrane, congested middle ear mucosa, myringosclerosis, ossicular chain discontinuity, sclerotic mastoids or treated septic foci in spite of the ear being dry for a month.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;Though many surgeons consider that 30 days of dry ear period is sufficient to consider tympanoplasty alone, there is a division of opinion among themselves while facing specific clinical scenarios.&lt;/p&gt;

Performance Assessment for Mastoidectomy.

Objective The aim of this report is to provide a review of the current literature for assessment of performance for mastoidectomy, to identify the current assessment tools available in the literature, and to summarize the evidence for their validity. Data Sources The MEDLINE database was accessed via PubMed. Review Methods Inclusion criteria consisted of English-language published articles that reported use of a mastoidectomy performance assessment tool. Studies ranged from 2007 to November 2015 and were divided into 2 groups: intraoperative assessments and those performed with simulation (cadaveric laboratory or virtual reality). Studies that contained specific reliability analyses were also highlighted. For each publication, validity evidence data were analyzed and interpreted according to conceptual definitions provided in a recent systematic review on the modern framework of validity evidence. Conclusions Twenty-three studies were identified that met our inclusion criteria for review, including 4 intraoperative objective assessment studies, 5 cadaveric studies, 10 virtual reality simulation studies, and 4 that used both cadaveric assessment and virtual reality. Implications for Practice A review of the literature revealed a wide variety of mastoidectomy assessment tools and varying levels of reliability and validity evidence. The assessment tool developed at Johns Hopkins possesses the most validity evidence of those reviewed. However, a number of agreed-on specific metrics could be integrated into a standardized assessment instrument to be used nationally. A universally agreed-on assessment tool will provide a means for developing standardized benchmarks for performing mastoid surgery.

The effect of self-directed virtual reality simulation on dissection training performance in mastoidectomy.

To establish the effect of self-directed virtual reality (VR) simulation training on cadaveric dissection training performance in mastoidectomy and the transferability of skills acquired in VR simulation training to the cadaveric dissection training setting. Prospective study. Two cohorts of 20 novice otorhinolaryngology residents received either self-directed VR simulation training before cadaveric dissection training or vice versa. Cadaveric and VR simulation performances were assessed using final-product analysis with three blinded expert raters. The group receiving VR simulation training before cadaveric dissection had a mean final-product score of 14.9 (95 % confidence interval [CI] [12.9-16.9]) compared with 9.8 (95% CI [8.4-11.1]) in the group not receiving VR simulation training before cadaveric dissection. This 52% increase in performance was statistically significantly (P < 0.0001). A single dissection mastoidectomy did not increase VR simulation performance (P = 0.22). Two hours of self-directed VR simulation training was effective in increasing cadaveric dissection mastoidectomy performance and suggests that mastoidectomy skills are transferable from VR simulation to the traditional dissection setting. Virtual reality simulation training can therefore be employed to optimize training, and can spare the use of donated material and instructional resources for more advanced training after basic competencies have been acquired in the VR simulation environment. NA. Laryngoscope, 126:1883-1888, 2016.

Peak and ceiling effects in final-product analysis of mastoidectomy performance.

Virtual reality surgical simulation of mastoidectomy is a promising training tool for novices. Final-product analysis for assessing novice mastoidectomy performance could be limited by a peak or ceiling effect. These may be countered by simulator-integrated tutoring. Twenty-two participants completed a single session of self-directed practice of the mastoidectomy procedure in a virtual reality simulator. Participants were randomised for additional simulator-integrated tutoring. Performances were assessed at 10-minute intervals using final-product analysis. In all, 45.5 per cent of participants peaked before the 60-minute time limit. None of the participants achieved the maximum score, suggesting a ceiling effect. The tutored group performed better than the non-tutored group but tutoring did not eliminate the peak or ceiling effects. Timing and adequate instruction is important when using final-product analysis to assess novice mastoidectomy performance. Improved real-time feedback and tutoring could address the limitations of final product based assessment.

Mastoidectomy performance assessment of virtual simulation training using final-product analysis.

The future development of integrated automatic assessment in temporal bone virtual surgical simulators calls for validation against currently established assessment tools. This study aimed to explore the relationship between mastoidectomy final-product performance assessment in virtual simulation and traditional dissection training. Prospective trial with blinding. A total of 34 novice residents performed a mastoidectomy on the Visible Ear Simulator and on a cadaveric temporal bone. Two blinded senior otologists assessed the final-product performance using a modified Welling scale. The simulator gathered basic metrics on time, steps, and volumes in relation to the on-screen tutorial and collisions with vital structures. Substantial inter-rater reliability (kappa = 0.77) for virtual simulation and moderate inter-rater reliability (kappa = 0.59) for dissection final-product assessment was found. The simulation and dissection performance scores had significant correlation (P = .014). None of the basic simulator metrics correlated significantly with the final-product score except for number of steps completed in the simulator. A modified version of a validated final-product performance assessment tool can be used to assess mastoidectomy on virtual temporal bones. Performance assessment of virtual mastoidectomy could potentially save the use of cadaveric temporal bones for more advanced training when a basic level of competency in simulation has been achieved. NA.

Virtual mastoidectomy performance evaluation through multi-volume analysis

Development of a visualization system that provides surgical instructors with a method to compare the results of many virtual surgeries (n>100). A masked distance field models the overlap between expert and resident results. Multiple volume displays are used side-by-side with a 2D point display. Performance characteristics were examined by comparing the results of specific residents with those of experts and the entire class. The software provides a promising approach for comparing performance between large groups of residents learning mastoidectomy techniques.

Utilization of Fluorescein for Identification and Preservation of the Facial Nerve and Semicircular Canals for Safe Mastoidectomy

Mastoidectomy can be a very challenging procedure for many reasons. The normal anatomy can be distorted because of inflammatory processes and tumors and recurrences. Avoiding injuries to the semicircular canals (SCCs) and facial canal is mandatory, and there is need to find a way to recognize the facial nerve and SCCs for safe performance of mastoidectomy. We describe, as a proof of concept, a novel technique to drill the mastoid while allowing the surgeon to recognize and avoid injuries to vital structures, in the cadaver. Four fresh cadaveric heads (8 sides) were prepared by cannulating the major vessels at the level of the neck. After removal of the mastoid cortex, indocyanine green was injected in the vessels. The sigmoid sinus alongside the facial nerve and SCCs was skeletonized using the drilling guidance provided by the fluorescence. The mucosa covering the air cells of the mastoid is very well vascularized compared with the thick bone representing the outer layer of the SCCs and facial canal. Consequently, after the indocyanine green injection, the mucosa shines whereas the bone does not. The fluorescence guides the drilling displaying air cells that are safe to remove. Eight mastoidectomies were performed, resulting in optimal drilling with no injuries to the facial canal and SCCs. With this novel technique, it is possible to perfectly skeletonize the facial nerve and the SCCs in the cadaver. We think that this technique can be an adjunct in the armamentarium of trainees that are not familiar with the anatomy of the temporal bone and eventually of neurosurgeons facing lesions that require the removal of various degrees of the mastoid.

Development of the First Force‐Controlled Robot for Otoneurosurgery

In some surgical specialties (eg, orthopedics), robots are already used in the operating room for bony milling work. Otological surgery and otoneurosurgery may also greatly benefit from the enhanced precision of robotics. Experimental study on robotic milling of oak wood and human temporal bone specimen. A standard industrial robot with a six-degrees-of-freedom serial kinematics was used, with force feedback to proportionally control the robot speed. Different milling modes and characteristic path parameters were evaluated to generate milling paths based on computer-aided design (CAD) geometry data of a cochlear implant and an implantable hearing system. The best-suited strategy proved to be the spiral horizontal milling mode with the burr held perpendicular to the temporal bone surface. To reduce groove height, the distance between paths should equal half the radius of the cutting burr head. Because of the vibration of the robot's own motors, a high oscillation of the SD of forces was encountered. This oscillation dropped drastically to nearly 0 Newton (N) when the burr head made contact with the dura mater, because of its damping characteristics. The cutting burr could be kept in contact with the dura mater for an extended period without damaging it, because of the burr's blunt head form. The robot moved the burr smoothly according to the encountered resistances. The study reports the first development of a functional robotic milling procedure for otoneurosurgery with force-based speed control. Future plans include implementation of ultrasound-based local navigation and performance of robotic mastoidectomy.