Procedural virtual reality simulation in minimally invasive surgery

Training and assessment for colorectal surgery and appendicectomy- a systematic review

AIM

There is currently an increased focus on competency-based training, in which training and assessment play a crucial role. The aim of this systematic review is to create an overview of hands-on training methods and assessment tools for appendicectomy and colon and rectal surgery procedures using either an open, laparoscopic or robot-assisted approach.

METHOD

A systematic review of Medline, Embase, Cochrane and Scopus databases was conducted following the PRISMA guidelines. We conducted the last search on 9 March 2023. All published papers describing hands-on training, evaluation of performance data and development of assessment tools were eligible. The quality of studies and the validity evidence of assessment tools are reported.

RESULTS

Fifty-one studies were identified. Laparoscopic assessment tools are abundant, but the literature still lacks good-quality assessment tools for open appendicectomy, robotic colectomy and open rectal surgery. Overall, there is a lack of discussion regarding the establishment of pass/fail standards and the consequences of assessment. Virtual reality simulation is used more for appendicectomy than colorectal procedures. Only a few of the studies investigating training were of acceptable quality. There is a need for high-quality studies in open and robotic-assisted colon surgery and all approaches to rectal surgery.

CONCLUSION

This review provides an overview of current training methods and assessment tools and identifies where more research is needed based on the quality of the studies and the current validity evidence.

An appropriate simulation-based training for surgical technology students

BACKGROUND

Using simulation in an appropriate education plan which has always been challenging; To be used alone or in combination with other methods and the order of it's use. This article was intended to compare student's knowledge, clinical skill and readiness-capability using simulation and combination of it with traditional training methods to collect necessary evidence for development of an appropriate simulation- based educational plan for surgical technology students.

METHODS

This is a controlled pre/post-test quasi-experimental study in 2019. All surgical technology students who had selected the scrub and circulate course (n = 28) were randomly divided into two groups. One of the groups was educated with traditional training method (TTM). On the same day, the other group was educated with simulation training method (STM). After two weeks, group α received simulation training and group β was subject to traditional training. Multiple-Choice Test for Knowledge Assessment and Clinical Skills as well as Readiness-Capability (KCSRC) of appendectomy Surgery checklist were used in this study. Data were analysed after each training method, after Two weeks and after blended education.For data analysis, Mixed-Design ANOVA and SPSS software 24/v were employed.

RESULTS

The mean scores of knowledge, clinical skills, and readiness-capability were 14.2 ± 2.91, 44.42 ± 17.74, 21.58 ± 4.18 in group α and 12.66 ± 3.21, 41.17 ± 16.19, and 18.58 ± 7.85 in group β, respectively. The comparison between mean scores of KCSRC before the first training and after combined training in each group showed that the mean of all scores significantly increased in group α (p < 0.0001), which indicates that the education plan starting with TTM and continued with STM has the most significant effect on results.

CONCLUSION

According to the results of the study, it seems that starting the education plan for surgical students with TTM and then continuing with STM would be more effective on education of students, especially on students' long term learning.

Cognitive and motor skill competence are different: Results from a prospective randomized trial using virtual reality simulator and educational video in laparoscopic cholecystectomy

BACKGROUND AND PURPOSE

Cognitive transfer represents an important issue in surgical education. It is essential for the acquisition of competence, such as decision making and error avoidance. This randomized study aims to compare the effectivity of cognitive transfer by observing the surgery versus using modern virtual reality simulators for learning a laparoscopic cholecystectomy.

METHOD

This was a prospective, randomized, single centre study. 40 medical students from a university hospital, a tertiary care teaching institution, were enrolled. After a short introduction of laparoscopic cholecystectomy, they were randomized into two groups (video group and simulator group). In the video group, participants watched the step-by-step educational video twice. In the simulator group, participants underwent training using the virtual reality simulator, including tutorial procedural tasks of laparoscopic cholecystectomy as well as a complete cholecystectomy on the simulator. After the training, cognitive competence including decision making and error awareness was assessed using a questionnaire.

RESULTS

In the most critical step of laparoscopic cholecystectomy, "Dissection in Calot's triangle", as well as in the aspect of planning next step, the video group was superior significantly (P = 0.038 and P = 0.04). No significant differences concerning the recognition of critical anatomical structures, choosing the necessary instruments as well as error awareness were found.

CONCLUSIONS

Learning by watching a high-quality educational video is more effective in acquiring the cognitive competence to combine learned single tasks. Traditional learning means as watching educational videos and modern, sophisticated VRS should be deployed complementarily to establish cognitive and motor competencies separately.

Haptic simulators accelerate laparoscopic simulator training, but skills are not transferable to a non-haptic simulator: a randomized trial

BACKGROUND

Laparoscopy requires specific psychomotor skills and can be challenging to learn. Most proficiency-based laparoscopic training programs have used non-haptic virtual reality simulators; however, haptic simulators can provide the tactile sensations that the surgeon would experience in the operating room. The objective was to investigate the effect of adding haptic simulators to a proficiency-based laparoscopy training program.

METHODS

A randomized controlled trial was designed where residents (n = 36) were randomized to proficiency-based laparoscopic simulator training using haptic or non-haptic simulators. Subsequently, participants from the haptic group completed a follow-up test, where they had to reach proficiency again using the non-haptic simulator. Participants from the non-haptic group returned to train until reaching proficiency again using the non-haptic simulator.

RESULTS

Mean completion times during the intervention were 120 min (SD 38.7 min) and 183 min (SD 66.3 min) for the haptic group and the non-haptic group, respectively (p = 0.001). The mean times to proficiency during the follow-up test were 107 min (SD 41.0 min) and 58 min (SD 23.7 min) for the haptic and the non-haptic group, respectively (p < 0.001). The haptic group was not faster to reach proficiency in the follow-up test than during the intervention (p = 0.22). In contrast, the non-haptic group reached the required proficiency level significantly faster in the follow-up test (p < 0.001).

CONCLUSION

Haptic virtual reality simulators reduce the time to reach proficiency compared to non-haptic simulators. However, the acquired skills are not transferable to the conventional non-haptic setting.

Development of pre-procedure virtual simulation for challenging interventional procedures: an experimental study with clinical application

Background

Most pain management techniques for challenging procedures are still performed under the guidance of the C-arm fluoroscope although it is sometimes difficult for even experienced clinicians to understand the modified three-dimensional anatomy as a two-dimensional X-ray image. To overcome these difficulties, the development of a virtual simulator may be helpful. Therefore, in this study, the authors developed a virtual simulator and presented its clinical application cases.

Methods

We developed a computer program to simulate the actual environment of the procedure. Computed tomography (CT) Digital Imaging and Communications in Medicine (DICOM) data were used for the simulations. Virtual needle placement was simulated at the most appropriate position for a successful block. Using a virtual C-arm, the authors searched for the position of the C-arm at which the needle was visualized as a point. The positional relationships between the anatomy of the patient and the needle were identified.

Results

For the simulations, the CT DICOM data of patients who visited the outpatient clinic was used. When the patients revisited the clinic, images similar to the simulated images were obtained by manipulating the C-arm. Transforaminal epidural injection, which was difficult to perform due to severe spinal deformity, and the challenging procedures of the superior hypogastric plexus block and Gasserian ganglion block, were successfully performed with the help of the simulation.

Conclusions

We created a pre-procedural virtual simulation and demonstrated its successful application in patients who are expected to undergo challenging procedures.

Effects of extended reality on language learning: A meta-analysis

In recent years, there has been increasing use of extended reality (XR) in language learning. Many scholars have conducted empirical research on the relationship between the two, but conclusions have been inconsistent, which calls for an organization and reanalysis of relevant literature. Articles published between 2000 and 2022 on the impact of XR on language learning were retrieved from the Web of Science and Scopus databases, and 17 of them (including 21 independent samples and 993 subjects) were included in this meta-analysis. The findings indicate that XR could promote language learning (effect size = 0.825). The moderating effects of education level, target language, and technology type were also tested, and the results indicate that the target language type significantly moderated the effect of XR technology on language learning (Q = 30.563, p < 0.001). Moreover, based on the subgroup analysis, several research questions worthy of further exploration in this field are discussed. Some suggestions are provided, noting that these technologies should be personally designed for learners and learning objects when applied in order to improve the effects of language learning.

The Effects of Virtual Reality-Assisted Language Learning: A Meta-Analysis

Existing literature reflects that VR technology is widely used in language learning settings. Although many studies have identified the multiple benefits and affordance of Virtual Reality (VR) technologies in language learning, most studies are qualitative studies that do not provide substantial evidence to investigate the impact of this technology on language learning. To this end, this study conducted a meta-analysis of 21 quantitative studies with 1144 participants published between 2010 and 2021. The study’s main purpose was to examine the effects of VR on students’ language learning academic performance, including linguistic gains and affective gains. The results indicated that VR-assisted language learning had a medium effect on the linguistic gains (Hedges’ g = 0.662, 95% CI [0.398–0.925], p < 0.001) and affective gains (Hedges’ g = 0.570, 95% CI [0.309–0.831], p < 0.001) of students compared to non-VR conditions, respectively. Furthermore, the study further analyzed the impact of several moderator variables such as education levels, hardware types, language skills, target language, and L1/L2 on language learning gains. The research indicates that VR technology has a great potential to improve language learning as an educational resource and provides suggestions for further research and practice on the use of VR-assisted language learning.

Procedural virtual reality simulation training for robotic surgery: a randomised controlled trial

Background

Virtual reality (VR) training is widely used for surgical training, supported by comprehensive, high-quality validation. Technological advances have enabled the development of procedural-based VR training. This study assesses the effectiveness of procedural VR compared to basic skills VR in minimally invasive surgery.

Methods

26 novice participants were randomised to either procedural VR (n = 13) or basic VR simulation (n = 13). Both cohorts completed a structured training programme. Simulator metric data were used to plot learning curves. All participants then performed parts of a robotic radical prostatectomy (RARP) on a fresh frozen cadaver. Performances were compared against a cohort of 9 control participants without any training experience. Performances were video recorded and assessed blindly using GEARS post hoc.

Results

Learning curve analysis demonstrated improvements in technical skill for both training modalities although procedural training was associated with greater training effects.

Any VR training resulted in significantly higher GEARS scores than no training (GEARS score 11.3 ± 0.58 vs. 8.8 ± 2.9, p = 0.002). Procedural VR training was found to be more effective than both basic VR training and no training (GEARS 11.9 ± 2.9 vs. 10.7 ± 2.8 vs. 8.8 ± 1.4, respectively, p = 0.03).

Conclusions

This trial has shown that a structured programme of procedural VR simulation is effective for robotic training with technical skills successfully transferred to a clinical task in cadavers. Further work to evaluate the role of procedural-based VR for more advanced surgical skills training is required.

Electronic supplementary material

The online version of this article (10.1007/s00464-020-08197-w) contains supplementary material, which is available to authorized users.

The Role of Simulators in Interdisciplinary Medical Work

This article reports from a project introducing a virtual reality simulator with patient-specific input for endovascular aneurysm repair (EVAR) into a surgical environment at a university hospital in Norway during 2016–2019. The project includes acquisition of the simulator, training of personnel, and a mapping of the effects. We followed the process, adopting ethnographic methods including participation in the operating room, simulated patient-specific rehearsals, preparations of the rehearsals, meetings with the simulator company, scientific meetings and scientific work related to the clinical trials (the second author led the clinical trial), in addition to open-ended interviews with vascular surgeons and interventional radiologists. We used the concepts of boundary work and sensework as conceptual lenses through which we studied the introduction of the simulator and how it influenced the nature of work and the professional relationship between the vascular surgeons and the interventional radiologists. We found that the simulator facilitated professional integration, at the same time as it served as a material resource for professional identity development. This study is the first to our knowledge that investigates the role of simulators for professional identity and relationship among surgeons and radiologists. Further studies of simulators in similar and different social contexts may contribute to deeper and more generic understanding of the way simulators influence our working life.

LAPKaans: Tool-Motion Tracking and Gripping Force-Sensing Modular Smart Laparoscopic Training System

Laparoscopic surgery demands highly skilled surgeons. Traditionally, a surgeon's knowledge is acquired by operating under a mentor-trainee method. In recent years, laparoscopic simulators have gained ground as tools in skill acquisition. Despite the wide range of laparoscopic simulators available, few provide objective feedback to the trainee. Those systems with quantitative feedback tend to be high-end solutions with limited availability due to cost. A modular smart trainer was developed, combining tool-tracking and force-using employing commercially available sensors. Additionally, a force training system based on polydimethylsiloxane (PDMS) phantoms for sample stiffness differentiation is presented. This prototype was tested with 39 subjects, between novices (13), intermediates (13), and experts (13), evaluating execution differences among groups in training exercises. The estimated cost is USD $200 (components only), not including laparoscopic instruments. The motion system was tested for noise reduction and position validation with a mean error of 0.94 mm. Grasping force approximation showed a correlation of 0.9975. Furthermore, differences in phantoms stiffness effectively reflected user manipulation. Subject groups showed significant differences in execution time, accumulated distance, and mean and maximum applied grasping force. Accurate information was obtained regarding motion and force. The developed force-sensing tool can easily be transferred to a clinical setting. Further work will consist on a validation of the simulator on a wider range of tasks and a larger sample of volunteers.

Empirical Evaluation of a 3D Virtual Simulator of Hysteroscopy Using Leap Motion for Gestural Interfacing

Surgical training using 3D virtual reality simulators has become an important routine in medical education. Recent research points to Leap Motion as an exciting interface for the control of virtual surgical instruments due to its simplicity and low-cost characteristics. However, previous studies using Leap Motion only evaluated movements of the whole hand, without considering individual finger movements during the manipulation of surgical instruments. This work investigates the use of Leap Motion as an interface for the capture of basic hand and finger movements during a simulated hysteroscopy using a 3D-printed hysteroscope model. We created a virtual simulated uterine environment containing a hysteroscope controlled by movements of the hand and fingers of a user actuating on a 3D-printed model hysteroscope. The model hysteroscope was positioned in a pivot basis allowing the capture of the following basic movements: leftward/rightward, upward/downward, forward/backward, and extrusion/retraction of the virtual resection loop (which rests on the end of the virtual virtual resectoscope). The findings indicate that the arc-shaped paths of the hysteroscope's alpha plane (rightward/leftward) and beta plane (upward/downward) movements are satisfactorily simulated by the virtual reality system. Using Intraclass Correlation, was noted that the similarity between the calculated (ideal standard) and measured arcs was highly significant on both planes (r = 0.9599 on the alpha plane, and r = 0.9208 on the beta plane). Also, the forward/backward trajectory is a straight line; the pinch gesture decreases its accuracy when increase its distance from the Interaction Box of Leap Motion. The results were satisfactorily since compared with previous works, which used Leap Motion for the capture of hands-free gesturing.

Bimanual Fundamentals: Validation of a New Curriculum for Virtual Reality Training of Laparoscopic Skills

Background. To determine face and construct validity for the new Bimanual Fundamentals curriculum for the Simendo^® Virtual Reality Laparoscopy Simulator and prove its efficiency as a training and objective assessment tool for surgical resident’s advanced psychomotor skills. Methods. 49 participants were recruited: 17 medical students (novices), 15 residents (intermediates), and 17 medical specialists (experts) in the field of gynecology, general surgery, and urology in 3 tertiary medical centers in the Netherlands. All participants performed the 5 exercises of the curriculum for 3 consecutive times on the simulator. Intermediates and experts filled in a questionnaire afterward, regarding the reality of the simulator and training goals of each exercise. Statistical analysis of performance was performed between novices, intermediates, and experts. Parameters such as task time, collisions/displacements, and path length right and left were compared between groups. Additionally, a total performance score was calculated for each participant. Results. Face validity scores regarding realism and training goals were overall positive (median scores of 4 on a 5-point Likert scale). Participants felt that the curriculum was a useful addition to the previous curricula and the used simulator would fit in their residency programs. Construct validity results showed significant differences on the great majority of measured parameters between groups. The simulator is able to differentiate between performers with different levels of laparoscopic experience. Conclusions. Face and construct validity for the new Bimanual Fundamental curriculum for the Simendo virtual reality simulator could be established. The curriculum is suitable to use in resident’s training programs to improve and maintain advanced psychomotor skills.

Operators believe patient-specific rehearsal improve individual and team performance

INTRODUCTION

Rehearsing endovascular aortic aneurysm repair on patient-specific data is recent within virtual reality simulation and opens up new possibilities for operators to prepare for complex procedures. This study evaluated the feasibility of patient-specific rehearsal (PsR) and assessed operators' appraisal of the VIST-LAB simulator from Mentice.

MATERIAL AND METHODS

CT-data was segmented and uploaded to the simulator, and simulated for 30 elective EVAR patients. Operators were asked how they perceived the PsR on a Likert scale after the PsR (once) and after the following procedure (each time).

RESULTS

Patients were simulated and operated by 14 operators, always in pairs of one vascular surgeon and one interventional radiologist. The operators estimated that PsR improved individual and team performance (median 4), and recommended the use of PsR in general (median 4) and for difficult cases (median 5). The simulator realism got moderate scores (median 2-3). Inexperienced operators seemed to appreciate the PsR the most.

CONCLUSIONS

PsR was feasible and was evaluated by operators to improve individual and team performance. Inexperienced users were more positive towards PsR than experienced users. PsR realism and the ease of importing patient-specific data can still be improved, and further studies to quantify and precisely identify benefits are needed.

Influence of patient-specific rehearsal on operative metrics and technical success for endovascular aneurysm repair

INTRODUCTION

Patient-specific rehearsal (PsR) is a recent technology within virtual reality (VR) simulation that lets the operators train on patient-specific data in a simulated environment prior to the procedure. Endovascular aneurysm repair (EVAR) is a complex procedure where operative metrics and technical success might improve after PsR.

MATERIAL AND METHODS

We compared technical success and operative metrics (endovascular procedure time, contralateral gate cannulation time, fluoroscopy time, total radiation dose, number of angiograms and contrast medium use) between 30 patients, where the operators performed PsR (the PsR group), and 30 patients without PsR (the control group).

RESULTS

The endovascular procedure time was significantly shorter in the PsR group than in the control group (median 44 versus 55 min, p = .017). The other operative metrics were similar. Technical success rates were higher in the PsR group, 96.7% primary and assisted primary outcome versus 90.0% in the control group. The differences were not significant (p = .076).

CONCLUSIONS

PsR before EVAR reduced endovascular procedure time, and our results indicate that it might improve technical success, but further studies are needed to confirm those results.

Say, What Is on Your Mind? Surgeons' Evaluations of Realism and Usability of a Virtual Reality Vertebroplasty Simulator

BACKGROUND

Virtual reality (VR)-based simulations offer rich opportunities for surgical skill training and assessment of surgical novices and experts. A structured evaluation and validation process of such training and assessment tools is necessary for effective surgical learning environments.

OBJECTIVE

To develop and apply a classification system of surgeon-reported experience during operation of a VR vertebroplasty simulator.

METHODS

A group of orthopedic, trauma surgeons and neurosurgeons (n = 13) with various levels of expertise performed on a VR vertebroplasty simulator. We established a mixed-methods design using think-aloud protocols, senior surgical expert evaluations, performance metrics, and a post-simulation questionnaire. Verbal content was systematically analyzed using structured qualitative content analysis. We established a category system for classification of surgeons' verbal evaluations during the simulation. Furthermore, we evaluated intraoperative performance metrics and explored potential associations with surgeons' characteristics and simulator evaluation.

RESULTS

Overall, 244 comments on realism and usability of the vertebroplasty simulator were collected. This included positive and negative remarks, questions, and specific suggestions for improvement. Further findings included surgeons' approval of the realism and usability of the simulator and the observation that the haptic feedback of the VR patient's anatomy requires further improvement. Surgeon-reported evaluations were not associated with performance decrements.

DISCUSSION

This study is the first to apply think-aloud protocols for evaluation of a surgical VR-based simulator. A novel classification approach is introduced that can be used to classify surgeons' verbalized experiences during simulator use. Our lessons learned may be valuable for future research with similar methodological approach.

High-Fidelity Endovascular Simulation

With the ongoing changes in graduate medical education, emphasis has been placed on simulation models to increase clinical exposure and optimize learning. In specific, high-fidelity simulation presents as a potential option for procedural-skill development in interventional radiology. With improved haptic, visual, and tactile dynamics, high-fidelity endovascular simulators have gained increasing support from trainees and certified interventionalists alike. The 2 most common high-fidelity endovascular simulators utilized today are the Procedicus VIST and ANGIO Mentor, which contain notable differences in technical features, case availability, and cost. From the perspective of a trainee, high-fidelity simulation allows for the ability to perform a greater volume of cases. Additionally, without the risk of potential harm to the patient, trainees can focus on repetition and improved performance in a stress-free environment. When errors are made, high-fidelity simulator metrics will generate instantaneous feedback and error notification, erasing ambiguity and thus facilitating learning. Furthermore, in an environment devoid of time and cost stressors, the supervising physician is afforded the opportunity to properly mentor and instruct the trainee throughout the case. For the experienced interventionalists, high-fidelity simulation allows for a decreased learning curve for new procedures or techniques, as well as the opportunity for procedure rehearsal for unusual or high-risk cases. Despite the limitations created by cost, high-fidelity endovascular simulation should continue to be increasingly utilized in the development of the interventional radiology curriculum.

Evaluating competency in video-assisted thoracoscopic surgery (VATS) lobectomy performance using a novel assessment tool and virtual reality simulation

BACKGROUND

Competency-based training has gained ground in surgical training and with it assessment tools to ensure that training objectives are met. Very few assessment tools are available for evaluating performance in thoracoscopic procedures. Video recordings would provide the possibility of blinded assessment and limited rater bias. This study aimed to provide validity evidence for a newly developed and dedicated tool for assessing competency in Video-Assisted Thoracoscopic Surgery (VATS) lobectomy.

METHODS

Participants with varying experience with VATS lobectomy were included from different countries. Video recordings from participants' performance of a VATS right upper lobe lobectomy on a virtual reality simulator were rated by three raters using a modified version of a newly developed VATS lobectomy assessment tool (the VATSAT) and analyzed in relation to the unitary framework (content, response process, internal structure, relation to other variables, and consequences of testing).

RESULTS

Fifty-three participants performed two consecutive simulated VATS lobectomies on the virtual reality simulator, leaving a total of 106 videos. Content established in previously published studies. Response process Standardized data collection was ensured by using an instructional element, uniform data collection, a special rating program, and automatic generation of the results to a database. Raters were carefully instructed in using the VATSAT, and tryout ratings were carried out. Internal structure Inter-rater reliability was calculated as intra-class correlation coefficients, to 0.91 for average measures (p < 0.001). Test/re-test reliability was calculated as Pearson's r of 0.70 (p < 0.001). G-coefficient was calculated to be 0.79 with two procedures and three raters. By performing D-theory was found that either three procedures rated by two raters or five procedures rated by one rater were enough to reach an acceptable G-coefficient of ≥ 0.8. Relation to other variables Significant differences between groups were found (p < 0.001). The participants' VATS lobectomy experience correlated significantly to their VATSAT score (p = 0.016). Consequences of testing The pass/fail score was found to be 14.9 points by the contrasting groups' method, leaving five false positive (29%) and six false negatives (43%).

CONCLUSION

Validity evidence was provided for the VATSAT according to the unitary framework. The VATSAT provides supervisors and assessors with a procedure-specific assessment tool for evaluating VATS lobectomy performance and aids with the decision of when the trainee is ready for unsupervised performance.

Three-Dimensional Printing of Life-Like Models for Simulation and Training of Minimally Invasive Cardiac Surgery

Objective

As the use of minimally invasive surgery in cardiothoracic surgery increases, so does the need for simulation and training. We developed a heart model for simulation and training of minimally invasive cardiac surgery, particularly minimally invasive mitral valve repair using our new three-dimensional printing system.

Methods

Digital imaging and communication in medicine data from patient computed tomography, three-dimensional computer-aided design, and three-dimensional printing helped create replicas of the heart and thoracic cavity. A polyvinyl alcohol model material with a texture and physical properties similar to those of heart tissue was initially used in mitral valve replicas to simulate surgical procedures. To develop this material, we mechanically investigated the composition of each part of the porcine heart.

Results

We investigated the elastic modulus and breaking strength of the porcine heart. Based on investigation results, the cardiac model was set at rupture strength 20 MPa, elastic modulus 0.17 MPa, and moisture content 85%. This provided a biotexture and feeling exactly like a patient heart. Computed tomography scans confirmed that the model shape was nearly the same as that of a human heart. We simulated minimally invasive mitral valve repair, including ring annuloplasty, chordal reconstruction, resection and suture, and edge-to-edge repair. Full surgery simulations using this model used minimally invasive cardiac surgery tools including a robot.

Conclusions

This life-like model can be used as a standard simulator to train younger, less experienced surgeons to practice minimally invasive cardiac surgery procedures and may help develop new operative tools.

A mixed-reality surgical trainer with comprehensive sensing for fetal laser minimally invasive surgery

PURPOSE

Smaller incisions and reduced surgical trauma made minimally invasive surgery (MIS) grow in popularity even though long training is required to master the instrument manipulation constraints. While numerous training systems have been developed in the past, very few of them tackled fetal surgery and more specifically the treatment of twin-twin transfusion syndrome (TTTS). To address this lack of training resources, this paper presents a novel mixed-reality surgical trainer equipped with comprehensive sensing for TTTS procedures. The proposed trainer combines the benefits of box trainer technology and virtual reality systems. Face and content validation studies are presented and a use-case highlights the benefits of having embedded sensors.

METHODS

Face and content validity of the developed setup was assessed by asking surgeons from the field of fetal MIS to accomplish specific tasks on the trainer. A small use-case investigates whether the trainer sensors are able to distinguish between an easy and difficult scenario.

RESULTS

The trainer was deemed sufficiently realistic and its proposed tasks relevant for practicing the required motor skills. The use-case demonstrated that the motion and force sensing capabilities of the trainer were able to analyze surgical skill.

CONCLUSION

The developed trainer for fetal laser surgery was validated by surgeons from a specialized center in fetal medicine. Further similar investigations in other centers are of interest, as well as quality improvements which will allow to increase the difficulty of the trainer. The comprehensive sensing appeared to be capable of objectively assessing skill.

The Validation of a Novel Robot-Assisted Radical Prostatectomy Virtual Reality Module

OBJECTIVE

To perform the first validation of a full procedural virtual reality robotic training module and analysis of novice surgeon's learning curves.

DESIGN

Participants completed the bladder neck dissection task and urethrovesical anastomosis task (UVA) as part of the prostatectomy module. Surgeons completed feedback questionnaires assessing the realism, content, acceptability and feasibility of the module. Novice surgeons completed a 5.5-hour training programme using both tasks.

SETTING

King's College London, London.

PARTICIPANTS

13 novice, 24 intermediate and 8 expert surgeons completed the validation study.

RESULTS

Realism was scored highly for BDN (mean 3.4/5) and UVA (3.74/5), as was importance of BDN (4.32/5) and UVA (4.6/5) for training. It was rated as a feasible (3.95/5) and acceptable (4/5) tool for training. Experts performed significantly better than novice group in 6 metrics in the UVA including time (p = 0.0005), distance by camera (p = 0.0010) and instrument collisions (p = 0.0033), as well as task-specific metrics such as number of unnecessary needle piercing points (p = 0.0463). In novice surgeons, a significant improvement in performance after training was seen in many metrics for both tasks. For bladder neck dissection task, this included time (p < 0.0001), instrument collisions (p = 0.0013) and total time instruments are out of view (p = 0.0251). For UVA, this included time (p = 0.0135), instrument collisions (p = 0.0066) and task-specific metrics such as injury to the urethra (p = 0.0032) and bladder (p = 0.0189).

CONCLUSIONS

Surgeons found this full procedural VR training module to be a realistic, feasible and acceptable component for a robotic surgical training programme. Construct validity was proven between expert and novice surgeons. Novice surgeons have shown a significant learning curve over 5.5 hours of training, suggesting this module could be used in a surgical curriculum for acquisition of technical skills. Further implementation of this module into the curriculum and continued analysis would be beneficial to gauge how it can be fully utilised.

Transferability of laparoscopic skills using the virtual reality simulator

BACKGROUND

Skill transfer represents an important issue in surgical education, and is not well understood. The aim of this randomized study is to assess the transferability of surgical skills between two laparoscopic abdominal procedures using the virtual reality simulator in surgical novices.

METHODS

From September 2016 to July 2017, 44 surgical novices were randomized into two groups and underwent a proficiency-based basic training consisting of five selected simulated laparoscopic tasks. In group 1, participants performed an appendectomy training on the virtual reality simulator until they reached a defined proficiency. They moved on to the tutorial procedural tasks of laparoscopic cholecystectomy. Participants in group 2 started with the tutorial procedural tasks of laparoscopic cholecystectomy directly. Finishing the training, participants of both groups were required to perform a complete cholecystectomy on the simulator. Time, safety and economy parameters were analysed.

RESULTS

Significant differences in the demographic characteristics and previous computer games experience between the two groups were not noted. Both groups took similar time to complete the proficiency-based basic training. Participants in group 1 needed significantly less movements (388.6 ± 98.6 vs. 446.4 ± 81.6; P < 0.05) as well as shorter path length (810.2 ± 159.5 vs. 945.5 ± 187.8 cm; P < 0.05) to complete the cholecystectomy compared to group 2. Time and safety parameters did not differ significantly between both groups.

CONCLUSION

The data demonstrate a positive transfer of motor skills between laparoscopic appendectomy and cholecystectomy on the virtual reality simulator; however, the transfer of cognitive skills is limited. Separate training curricula seem to be necessary for each procedure for trainees to practise task-specific cognitive skills effectively. Mentoring could help trainees to get a deeper understanding of the procedures, thereby increasing the chance for the transfer of acquired skills.

"How To" Videos Improve Residents Performance of Essential Perioperative Electronic Medical Records and Clinical Tasks

OBJECTIVE

The ability to use electronic medical records (EMR) is an essential skill for surgical residents. However, frustration and anxiety surrounding EMR tasks may detract from clinical performance. We created a series of brief, 1-3 minutes "how to" videos demonstrating 7 key perioperative EMR tasks: booking OR cases, placing preprocedure orders, ordering negative-pressure wound dressing supplies, updating day-of-surgery history and physical notes, writing brief operative notes, discharging patients from the postanesthesia care unit, and checking vital signs. Additionally, we used "Cutting Insights"-a locally developed responsive mobile application for surgical trainee education-as a platform for providing interns with easy access to these videos. We hypothesized that exposure to these videos would lead to increased resident efficiency and confidence in performing essential perioperative tasks, ultimately leading to improved clinical performance.

METHODS

Eleven surgery interns participated in this initiative. Before watching the "how to" videos, each intern was timed performing the aforementioned 7 key perioperative EMR tasks. They also underwent a simulated perioperative emergency requiring the performance of 3 of these EMR tasks in conjunction with 5 other required interventions (including notifying the chief resident, the anesthesia team, and the OR coordinator; and ordering fluid boluses, appropriate laboratories, and blood products). These simulations were scored on a scale from 0 to 8. The interns were then directed to watch the videos. Two days later, their times for performing the 7 tasks and their scores for a similar perioperative emergency simulation were once again recorded. Before and after watching the videos, participants were surveyed to assess their confidence in performing each EMR task using a 5-point Likert scale. We also elicited their opinions of the videos and web-based mobile application using a 5-point scale. Statistical analyses to assess for statistical significance (p ≤ 0.05) were conducted using paired t-test for parametric variables and a Wilcoxon matched-pair test for nonparametric variables.

SETTING

Hospital of the University of Pennsylvania, Philadelphia, PA (a quaternary teaching hospital within the University of Pennsylvania Health System).

PARTICIPANTS

Eleven out of 15 interns (12 entered and 11 completed the study) from our categorical and preliminary general surgery residency programs during the 2016 academic year.

RESULTS

Before exposure to the brief "how to" videos, 6 of 11 interns were unable to complete all 7 EMR tasks; after exposure, all 11 interns were able to complete all 7 EMR tasks. Moreover, interns' times for each task improved following exposure. Interns self-reported improved confidence in booking an OR case (4 ± 0.9 vs. 4.7 ± 0.6, p = 0.05), ordering negative-pressure wound therapy supplies (3.1 ± 1.6 vs. 4.5 ± 0.7, p < 0.05), writing a brief operative note (3.7 ± 1.2 vs. 4.6 ± 0.7, p = 0.05), discharging patients from the postanesthesia care unit (3.3 ± 1.0 vs. 4.4 ± 0.8, p < 0.05), checking vital signs (2.5 ± 1.4 vs. 4.5 ± 0.8, p ≤ 0.01), and performing necessary EMR tasks during an emergency situation (2.4 ± 0.8 vs. 4.6 ± 0.7, p ≤ 0.0001). Participants also demonstrated a significant improvement in average clinical score on the emergency simulations (5.2 ± 1.7 vs. 6.6 ± 0.9, p < 0.05). Interns' opinions of the videos and the mobile phone application were favorable.

CONCLUSIONS

In our group of 11 surgery interns, exposure to a series of short "how to" videos led to increased confidence and shortened times in performing 7 essential EMR tasks. Additionally, during a simulated perioperative emergency, EMR tasks were performed significantly faster. Clinical performance also improved significantly following exposure to the videos. This just-in-time educational intervention could improve workflow efficiency and clinical performance, both of which may ultimately enhance perioperative patient safety.

Validation of the mobile serious game application Touch Surgery™ for cognitive training and assessment of laparoscopic cholecystectomy

BACKGROUND

Touch Surgery^™ (TS) is a serious gaming application for cognitive task simulation and rehearsal of key steps in surgical procedures. The aim was to establish face, content, and construct validity of TS for laparoscopic cholecystectomy (LC). Furthermore, learning curves with TS and a virtual reality (VR) trainer were compared in a randomized trial.

METHODS

The performance of medical students and general surgeons was compared for all three modules of LC in TS to establish construct validity. Questionnaires assessed face and content validity. For analysis of learning curves, students were randomized to train on VR or TS first, and then switched to the other training modality. Performance data were recorded.

RESULTS

54 Surgeons and 51 medical students completed the validation study. Surgeons outperformed students with TS: patient preparation (students = 45.0 ± 19.1%; surgeons = 57.3 ± 15.2%; p < 0.001), access and laparoscopy (students = 70.2 ± 10.9%; surgeons = 75.9 ± 9.7%; p = 0.008) and LC (students = 69.8 ± 12.4%; surgeons = 77.7 ± 9.6%; p < 0.001). Both groups agreed that TS was a highly useful and realistic application. 46 students were randomized for learning curve analysis. It took them 2-4 attempts to reach a 100% score with TS. Training with TS first did not improve students' performance on the VR trainer; however, students who trained with VR first scored significantly higher in module 3 of TS.

CONCLUSION

TS is an accepted serious gaming application for learning cognitive aspects of LC with established construct, face, and content validity. There appeared to be a synergy between TS and the VR trainer. Therefore, the two training modalities should accompany one another in a multimodal training approach to laparoscopy.

Evaluation of Procedural Simulation as a Training and Assessment Tool in General Surgery-Simulating a Laparoscopic Appendectomy

BACKGROUND

Laparoscopic appendectomy is a commonly performed surgical procedure, but few training models have been described for it. We examined a virtual reality module for practising a laparoscopic appendectomy.

METHODS

A prospective cohort study with the following 3 groups of surgeons (n = 45): novices (0 procedures), intermediates (10-50 procedures), and experienced (>100 procedures). After being introduced to the simulator and 1 familiarization attempt on the procedural module, the participants practiced the module 20 times. Movements, task time, and procedure-specific parameters were compared over time.

RESULTS

The time and movement parameters were significantly different during the first attempt, and more experienced surgeons used fewer movements and less time than novices (p < 0.01), although only 2 parameters were significantly different between novices and intermediates. All 3 groups improved significantly over 20 attempts (p < 0.0001). The intraclass correlation coefficient varied between 0.55 and 0.68 and did not differ significantly between the 3 groups (p > 0.05). When comparing novices with experienced surgeons, novices had a higher risk of burn damage to cecum (odds ratio [OR] = 3.0 [95% CI: 1.3; 7.0] p = 0.03), pressure damage to appendix (OR = 3.1 [95% CI: 2.0; 4.9] p < 0.0001), and grasping of the appendix (OR = 2.9 [95% CI: 1.8; 4.7] p < 0.0001). The risk of causing a perforation was not significantly different among the different experience levels (OR = 1.9 [95% CI: 0.9; 3.8] p = 0.14). Only 3 out of 5 error parameters differed significantly when comparing novices and experienced surgeons. Similarly, when comparing intermediates and novices, it was only 2 of the parameters that differed.

DISCUSSION

The simulator module for practising laparoscopic appendectomy may be useful as a training tool, but further development is required before it can be used for assessment purposes. Procedural simulation may demonstrate more variation for movement parameters, and future research should focus on developing better procedure-specific parameters.

Achieving Interface and Environment Fidelity in the Virtual Basic Laparoscopic Surgical Trainer

Virtual reality trainers are educational tools with great potential for laparoscopic surgery. They can provide basic skills training in a controlled environment and free of risks for patients. They can also offer objective performance assessment without the need for proctors. However, designing effective user interfaces that allow the acquisition of the appropriate technical skills on these systems remains a challenge. This paper aims to examine a process for achieving interface and environment fidelity during the development of the Virtual Basic Laparoscopic Surgical Trainer (VBLaST). Two iterations of the design process were conducted and evaluated. For that purpose, a total of 42 subjects participated in two experimental studies in which two versions of the VBLaST were compared to the accepted standard in the surgical community for training and assessing basic laparoscopic skills in North America, the FLS box-trainer. Participants performed 10 trials of the peg transfer task on each trainer. The assessment of task performance was based on the validated FLS scoring method. Moreover, a subjective evaluation questionnaire was used to assess the fidelity aspects of the VBLaST relative to the FLS trainer. Finally, a focus group session with expert surgeons was conducted as a comparative situated evaluation after the first design iteration. This session aimed to assess the fidelity aspects of the early VBLaST prototype as compared to the FLS trainer. The results indicate that user performance on the earlier version of the VBLaST resulting from the first design iteration was significantly lower than the performance on the standard FLS box-trainer. The comparative situated evaluation with domain experts permitted us to identify some issues related to the visual, haptic and interface fidelity on this early prototype. Results of the second experiment indicate that the performance on the second generation VBLaST was significantly improved as compared to the first generation and not significantly different from that of the standard FLS box-trainer. Furthermore, the subjects rated the fidelity features of the modified VBLaST version higher than the early version. These findings demonstrate the value of the comparative situated evaluation sessions entailing hands on reflection by domain experts to achieve the environment and interface fidelity and training objectives when designing a virtual reality laparoscopic trainer. This suggests that this method could be used successfully in the future to enhance the value of VR systems as an alternative to physical trainers for laparoscopic surgery skills. Some recommendations on how to use this method to achieve the environment and interface fidelity of a VR laparoscopic surgical trainer are identified.

Does Warm-Up Training in a Virtual Reality Simulator Improve Surgical Performance? A Prospective Randomized Analysis

INTRODUCTION

Virtual reality surgical simulators (VRSS) have been showing themselves as a valuable tool in laparoscopy training and education. Taking in consideration the effectiveness of the VRSS, new uses for this tool have been purposed. In sports, warming up before exercise clearly shows benefit in performance. It is hypothesized that warming up in the VRSS before going to the operating room may show benefit in surgical performance.

OBJECTIVE

Verify whether there is benefit in surgical performance with preoperatory warm-up using a VRSS.

MATERIALS AND METHODS

A total of 20 medical students with basic knowledge in laparoscopy were divided in 2 groups (I and II). Group I performed a laparoscopic cholecystectomy in a porcine model. Group II performed preoperative warm-up in a VRSS and then performed a laparoscopic cholecystectomy in a porcine model. The performance between both groups was compared regarding quantitative parameters (time for dissection of the gallbladder pedicle, time for clipping the pedicle, time for cutting the pedicle, time for gallbladder removal, total operative time, and aspirated blood loss) and qualitative parameters (depth perception, bimanual dexterity, efficiency, tissue handling, and autonomy) based on a previously validated score system, in which the higher the score, the better the result. Data were analyzed with level of significance of 5%.

RESULTS

The group that underwent preoperative warm-up (group II) showed significantly superior results as to the time for dissection of the gallbladder pedicle (11.91 ± 9.85 vs. 4.52 ± 2.89min, p = 0.012), time for clipping the pedicle (5.51 ± 2.36 vs. 2.89 ± 2.76min, p = 0.004), time for cutting the pedicle (1.84 ± 0.7 vs. 1.13 ± 0.51, p = 0.019), aspirated blood loss (171 ± 112 vs. 57 ± 27.8ml, p = 0.006), depth perception (4.5 ± 0.7 vs. 3.3 ± 0.67, p = 0.004), bianual dexterity (4.2 ± 0.78 vs. 3.3 ± 0.67, p = 0.004), tissue handling (4.2 ± 0.91 vs. 3.6 ± 0.66, p = 0.012), and autonomy (4.9 ± 0.31 vs. 3.6 ± 0.96, p = 0.028). There was no difference in time for gallbladder removal (11.58 ± 4.31 vs. 15.08 ± 4.51min, p = 0.096), total operative time (30.8 ± 11.07 vs. 25.60 ± 5.10min, p = 0.188), and efficiency (4 ± 0.66 vs. 3.6 ± 0.69, p = 0.320).

CONCLUSION

The practice of preoperative warm-up training seems to benefit surgical performance even in subject with mild laparoscopic experience.

Using virtual reality simulation to assess competence in video-assisted thoracoscopic surgery (VATS) lobectomy

BACKGROUND

The societies of thoracic surgery are working to incorporate simulation and competency-based assessment into specialty training. One challenge is the development of a simulation-based test, which can be used as an assessment tool. The study objective was to establish validity evidence for a virtual reality simulator test of a video-assisted thoracoscopic surgery (VATS) lobectomy of a right upper lobe.

METHODS

Participants with varying experience in VATS lobectomy were included. They were familiarized with a virtual reality simulator (LapSim^®) and introduced to the steps of the procedure for a VATS right upper lobe lobectomy. The participants performed two VATS lobectomies on the simulator with a 5-min break between attempts. Nineteen pre-defined simulator metrics were recorded.

RESULTS

Fifty-three participants from nine different countries were included. High internal consistency was found for the metrics with Cronbach's alpha coefficient for standardized items of 0.91. Significant test-retest reliability was found for 15 of the metrics (p-values <0.05). Significant correlations between the metrics and the participants VATS lobectomy experience were identified for seven metrics (p-values <0.001), and 10 metrics showed significant differences between novices (0 VATS lobectomies performed) and experienced surgeons (>50 VATS lobectomies performed). A pass/fail level defined as approximately one standard deviation from the mean metric scores for experienced surgeons passed none of the novices (0 % false positives) and failed four of the experienced surgeons (29 % false negatives).

CONCLUSION

This study is the first to establish validity evidence for a VATS right upper lobe lobectomy virtual reality simulator test. Several simulator metrics demonstrated significant differences between novices and experienced surgeons and pass/fail criteria for the test were set with acceptable consequences. This test can be used as a first step in assessing thoracic surgery trainees' VATS lobectomy competency.

Randomized trial to examine procedure-to-procedure transfer in laparoscopic simulator training

Background

Laparoscopic simulation has become a standard component of surgical training, but there is limited knowledge regarding skills transfer between procedural tasks. The objective was to investigate the specificity of procedural simulator training.

Methods

This was randomized single-centre educational superiority trial. Surgical novices practised basic skills on a laparoscopic virtual reality simulator. On reaching proficiency, participants were randomized to proficiency-based training. The intervention group practised two procedures on the simulator (appendicectomy followed by salpingectomy), whereas the control group trained on only one procedure (salpingectomy). The main outcomes were number of repetitions and time to proficiency for the second procedure.

Results

Ninety-six participants were randomized, of whom 74 per cent were women, with a median age of 26 years. The intervention group needed significantly fewer attempts than the control group to reach proficiency in the second procedure: median (i.q.r.) 22 (17–34) versus 32 (26–41) attempts, which corresponded to 24·1 per cent fewer attempts as assessed by multivariable analysis (P = 0·004). The intervention group required significantly less time than the control group to reach proficiency: median (i.q.r.) 88 (63–127) versus 131 (101–153) min respectively, corresponding to a difference of 31·1 min as assessed by multivariable analysis (P = 0·001).

Conclusion

Practising two procedures, compared with only one, reduced the number of attempts and time to reach proficiency in the second procedure. Skills transfer is seen between two tasks in laparoscopic simulator training; however, task specificity is still present when practising procedures. Registration number: NCT02069951 (http://www.clinicaltrials.gov).

Medical students as facilitators for laparoscopic simulator training

BACKGROUND

Teaching basic clinical skills to student peers and residents by medical students has previously been shown effective. This study examines if medical students can facilitate laparoscopic procedural tasks to residents using a virtual reality simulator.

METHODS

This was a retrospective study comparing 2 groups of gynecology residents. One group was instructed by 2 student facilitators, and a resident facilitator instructed the other group. Facilitators in both the groups were experienced in laparoscopic simulator training. The outcome measures were time and repetitions to complete a laparoscopic simulator training program.

RESULTS

A total of 51 residents participated: 15 in the student-facilitated group and 36 in the resident-facilitated group after 18 and 7 residents dropped out, respectively. The student-facilitated group averaged 230 minutes, while the resident-facilitated group averaged 200 minutes (p = 0.724). To complete the final examination module, the student-facilitated group required 19.5 repetitions vs 39.2 in the resident-facilitated group (p = 0.007).

CONCLUSION

Our findings suggest that students can be used as facilitators as an alternative to residents when practicing on a laparoscopic virtual reality simulator.

Procedural specificity in laparoscopic simulator training: protocol for a randomised educational superiority trial

BACKGROUND

The use of structured curricula for minimally invasive surgery training is becoming increasingly popular. However, many laparoscopic training programs still use basic skills and isolated task training, despite increasing evidence to support the use of training models with higher functional resemblance, such as whole procedural modules. In contrast to basic skills training, procedural training involves several cognitive skills such as elements of planning, movement integration, and how to avoid adverse events. The objective of this trial is to investigate the specificity of procedural practice in laparoscopic simulator training.

METHODS/DESIGN

A randomised single-centre educational superiority trial. Participants are 96 surgical novices (medical students) without prior laparoscopic experience. Participants start by practicing a series of basic skills tasks to a predefined proficiency level on a virtual reality laparoscopy simulator. Upon reaching proficiency, the participants are randomised to either the intervention group, which practices two procedures (an appendectomy followed by a salpingectomy) or to the control group, practicing only one procedure (a salpingectomy) on the simulator. 1:1 central randomisation is used and participants are stratified by sex and time to complete the basic skills. Data collection is done at a surgical skills centre.The primary outcome is the number of repetitions required to reach a predefined proficiency level on the salpingectomy module. The secondary outcome is the total training time to proficiency. The improvement in motor skills and effect on cognitive load are also explored.

DISCUSSION

The results of this trial might provide new knowledge on how the technical part of surgical training curricula should be comprised in the future. To examine the specificity of practice in procedural simulator training is of great importance in order to develop more comprehensive surgical curricula.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02069951.

Simulator-based transesophageal echocardiographic training with motion analysis: a curriculum-based approach

BACKGROUND

Transesophageal echocardiography (TEE) is a complex endeavor involving both motor and cognitive skills. Current training requires extended time in the clinical setting. Application of an integrated approach for TEE training including simulation could facilitate acquisition of skills and knowledge.

METHODS

Echo-naive nonattending anesthesia physicians were offered Web-based echo didactics and biweekly hands-on sessions with a TEE simulator for 4 weeks. Manual skills were assessed weekly with kinematic analysis of TEE probe motion and compared with that of experts. Simulator-acquired skills were assessed clinically with the performance of intraoperative TEE examinations after training. Data were presented as median (interquartile range).

RESULTS

The manual skills of 18 trainees were evaluated with kinematic analysis. Peak movements and path length were found to be independent predictors of proficiency (P < 0.01) by multiple regression analysis. Week 1 trainees had longer path length (637 mm [312 to 1,210]) than that of experts (349 mm [179 to 516]); P < 0.01. Week 1 trainees also had more peak movements (17 [9 to 29]) than that of experts (8 [2 to 12]); P < 0.01. Skills acquired from simulator training were assessed clinically with eight additional trainees during intraoperative TEE examinations. Compared with the experts, novice trainees required more time (199 s [193 to 208] vs. 87 s [83 to 16]; P = 0.002) and performed more transitions throughout the examination (43 [36 to 53] vs. 21 [20 to 23]; P = 0.004).

CONCLUSIONS

A simulation-based TEE curriculum can teach knowledge and technical skills to echo-naive learners. Kinematic measures can objectively evaluate the progression of manual TEE skills.

An approach to EVAR simulation using patient specific modeling

BACKGROUND

The Simbionix Angiomentor Procedure Rehearsal Studio (PRS) offers accurate virtual anatomy for measurement, stent graft selection, and deployment of endovascular aneurysm repair (EVAR) devices.

METHODS

Selected Gore Excluder EVAR cases from our EVAR database were reviewed and DICOM data loaded into the Simbionix Angiomentor simulator using PRS software. Using centerline measurements created on PRS, neck diameter (D1), length from lowest renal artery to each iliac bifurcation (Ll and Lr), and common iliac artery diameter (Dl and Dr) were recorded. All measurements for device selection were made based on data recorded on the simulator. Simulated EVAR was then performed using PRS on a dual limb endovascular simulator. Changes in device selection based on intraoperative measurements and use of three-dimensional (3D) anatomic overlay made by the attending vascular surgeon performing the case were recorded. The devices actually used for successful repair were considered gold standard for comparison. At the completion of each virtual case, simulations were rated by an experienced vascular surgeon for realism, imaging quality, and final product on a 5-point scale.

RESULTS

Ten cases with complete operative data and available computed tomography scans were chosen at random. Fifty percent of the cases (5/10) had changes in device length when using the "in vivo" 3D volume filled model and angiographic measurements. Analysis of variance revealed no significant differences between the groups in any measurement-main body diameter P = 0.960; main body length P = 0.643; and contralateral limb length P = 0.333. Review of simulation scoring showed ratings of diminished realism (average 2.3/5) due to unrealistic ease of wire passage and gate cannulation; however, simulation imaging and final product were scored favorably (3.7 and 3.4, respectively).

CONCLUSIONS

The use of centerlines, angiographic measurements, and 3D modeling within the PRS software approaches real-life device selection and represents an opportunity for high fidelity patient-specific preoperative EVAR case rehearsal.