Modeling Haptic Interactions in Endoscopic Submucosal Dissection (ESD).

The ability to provide realistic haptic feedback is indispensable for virtual-reality (VR) based endoscopic colorectal surgery simulators. Despite its importance, force feedback is commonly simulated by simplified approximations with parameters manually tuned in preliminary evaluations due to the complexity of the dynamics of haptic interaction in colonoscopy interventions. Endoscopic submucosal dissection (ESD) is a particularly challenging intervention that requires advanced manual skills for endoscopic control. This work proposes a mechanical impedance model for haptic interactions in ESD formulated via an experimental methodology applied to endoscopic colorectal interventions in general. The developed model is shown to capture the variations in the interaction force during two operations performed at distinct locations on a porcine sample. Salient cues in the recorded haptic interaction data are presented, and changes in the impedance characteristics of the tool-tissue interaction between the steps of the operation are analyzed.

Training on a virtual reality cricothyroidotomy simulator improves skills and transfers to a simulated procedure.

Objective: The virtual airway skills trainer (VAST) is a virtual reality simulator for training in cricothyroidotomy (CCT). The goal of the study is to test the effectiveness of training and transfer of skills of the VAST-CCT. Methods: Two groups, control (no training) and simulation (2 weeks of proficiency-based training), participated in this study. Subjects in the control condition did not receive any training on the task whereas those in the simulation received a proficiency-based training on the task during a period of 2 weeks. Two weeks post-training, both groups performed CCT on the TraumaMan to demonstrate the transfer of skills. Results: A total of (n=20) subjects participated in the study. The simulation group performed better than the control group at both the post-test (p<0.001) and retention test (p<0.001) on the simulator. The cumulative sum analysis showed that all subjects in the simulation group reached proficiency with acceptable failure rate within the 2 weeks of training. On the transfer test, the simulation group performed better on skin cut (p<0.001), intubation (p<0.001) and total score (p<0.001) than the control group. Conclusions: The VAST-CCT is effective in training and skills transfer for the CCT procedure. Level of evidence: Not applicable. Simulator validation study.

Surgeons With Five or More Actual Cricothyrotomies Perform Significantly Better on a Virtual Reality Simulator.

BACKGROUND: Discriminating performance of learners with varying experience is essential to developing and validating a surgical simulator. For rare and emergent procedures such as cricothyrotomy (CCT), the criteria to establish such groups are unclear. This study is to investigate the impact of surgeons' actual CCT experience on their virtual reality simulator performance and to determine the minimum number of actual CCTs that significantly discriminates simulator scores. Our hypothesis is that surgeons who performed more actual CCT cases would perform better on a virtual reality CCT simulator. METHODS: 47 clinicians were recruited to participate in this study at the 2018 annual conference of the Society of American Gastrointestinal and Endoscopic Surgeons. We established groups based on three different experience thresholds, that is, the minimal number of CCT cases performed (1, 5, and 10), and compared simulator performance between these groups. RESULTS: Participants who had performed more clinical cases manifested higher mean scores in completing CCT simulation tasks, and those reporting at least 5 actual CCTs had significantly higher (P = 0.014) simulator scores than those who had performed fewer cases. Another interesting finding was that classifying participants based on experience level, that is, attendings, fellows, and residents, did not yield statistically significant differences in skills related to CCT. CONCLUSIONS: The simulator was sensitive to prior experience at a threshold of 5 actual CCTs performed.

Characterization of Applied Forces and Torques During Rigid Bronchoscopy Intubation.

BACKGROUND: Rigid bronchoscopy intubation poses a significant risk of complication to patients from mechanical trauma. Despite the importance of precision in forces exerted by surgeons during intubation, no prior study has analyzed the overall forces and torques involved in rigid bronchoscopy intubation, and whether existing training modalities accurately replicate them. METHODS: A bronchoscope was equipped with a 6-axis load sensor to measure forces and torques applied during rigid bronchoscopy intubation. The device was applied to measure intubation forces in low-fidelity manikins and patients by interventional pulmonologists. RESULTS: Axial and lateral forces were measured during rigid bronchoscope intubation from the mouth to the mid-trachea. The mean axial/lateral forces recorded during manikin trials were 6.93/18.06 N, whereas those recorded during patient trials were 4.57/9.43 N. Average axial and lateral force application was therefore 51.6% and 92.6% higher in manikin, respectively. Applied axial torque averaged across all human trials was 130.5 N-mm compared with 78.3 N-mm for manikin trials, 40% lower in manikin than in human. Lateral torque application during manikin intubation showed greater variation in between trials and a greater range of SDs within trials. CONCLUSION: This was the first application of a rigid bronchoscope measurement device designed to measure forces applied at the handle. Force and torque discrepancies between manikin training and patient applications were found, indicating a possible mismatch between the haptic feedback received by physicians during rigid training and application. This inconsistency could be resolved via novel haptic training modalities and help increase atraumatic intubations.

Endoscopic submucosal dissection: a cognitive task analysis framework toward training design.

BACKGROUND: One of the major impediments to the proliferation of endoscopic submucosal dissection (ESD) training in Western countries is the lack of sufficient experts as instructors. One way to address this gap is to develop didactic systems, such as surgical simulators, to support the role of trainers. Cognitive task analysis (CTA) has been used in healthcare for the design and improvement of surgical training programs, and therefore can potentially be used for design of similar systems for ESD. OBJECTIVE: The aim of the study was to apply a CTA-based approach to identify the cognitive aspects of performing ESD, and to generate qualitative insights for training. MATERIALS AND METHODS: Semi-structured interviews were designed based on the CTA framework to elicit knowledge of ESD practitioners relating to the various tasks involved in the procedure. Three observations were conducted of expert ESD trainers either while they performed actual ESD procedures or at a training workshop. Interviews were either conducted over the phone or in person. Interview participants included four experts and four novices. The observation notes and interviews were analyzed for emergent qualitative themes and relationships. RESULTS: The qualitative analysis yielded thematic insights related to four main cognition-related categories: learning goals/principles, challenges/concerns, strategies, and decision-making. The specific insights under each of these categories were systematically mapped to the various tasks inherent to the ESD procedure. CONCLUSIONS: The CTA approach was applied to identify cognitive themes related to ESD procedural tasks. Insights developed based on the qualitative analysis of interviews and observations of ESD practitioners can be used to inform the design of ESD training systems, such as virtual reality-based simulators.