Simulation Training in Urology

Abstract

Purpose of review:

This review outlines recent innovations in simulation technology as it applies to urology. It is essential for the next generation of urologists to attain a solid foundation of technical and non-technical skills, and simulation technology provides a variety of safe, controlled environments to acquire this baseline knowledge.

Recent findings:

With a focus on urology, this review first outlines the evidence to support surgical simulation, then discusses the strides being made in the development of 3D-printed models for surgical skill training and pre-operative planning, virtual reality models for different urologic procedures, surgical skill assessment for simulation, and integration of simulation into urology residency curricula.

Summary:

Simulation continues to be an integral part of the journey towards the mastery of skills necessary for becoming an expert urologist. Clinicians and researchers should consider how to further incorporate simulation technology into residency training and help future generations of urologists throughout their career.

Introduction

Simulation can be defined as “the technique of imitating behavior of some situation or process by means of a suitably analogous situation or apparatus.”¹ In other words, simulation can be thought of as a close representation of a system capable of serving as a tool on which to practice a task before performing the real thing. The medical field is at the absolute forefront of the development of simulations of all kinds: emergency preparedness drills, surgical training simulators, medical imaging phantoms, and technology-equipped mannequins are just a few examples. Simulation training is an integral part of modern surgical training as residents work to build a foundation of technical and non-technical skills before they perform procedures in the clinic or in the operating room.² Furthermore, acquisition of a high degree of surgical expertise is directly correlated with better patient outcomes which reinforces the need for high fidelity practice in safe, controlled settings.³ In this review, we evaluate the recent advancements in simulation technology as it applies to the field of urology. We explore new evidence to support simulation training, new technology such as 3D printing and telestration, innovation in urologic procedural simulation, surgical skill assessment, integration of simulation into urology residency curricula, and the future of simulation in urology. We included publications from July, 2022 to July, 2023 to outline the true cutting edge of simulation technology. Literature was accumulated via a PubMed search using terms “training,” “simulation,” “curriculum,” and “urology,” and screened by two authors.

New Evidence for Surgical Simulation

Transitioning from Halstead’s traditional apprenticeship model to a contemporary, more standardized surgical training approach, it’s logical to believe that simulations would enhance the training of surgical residents, akin to their role in pilot training.⁴ Yet, it is only recently that robust evidence has emerged to validate the efficacy of simulations in surgical training. Key concerns have centered on the realism of simulations, the transfer of skills to live surgery, and the adaptability of simulation to individual patient variation. Several recent, comprehensive studies have now addressed these questions.

In endourology, Aydin et al. conducted an international, multi-center, randomized-controlled trial, SIMULATE (Simulation in Urological Training and Education), using ureteroscopy as a benchmark to assess whether standardized simulation training enables residents to attain proficiency sooner with better patient outcomes.⁵ The simulation curriculum consists of didactic lectures andpractices on the URO-Mentor virtual reality (VR) simulator, dry-laboratory models, and fresh frozen cadavers.⁵ The study found that while the number of procedures required to reach proficiency was similar for simulation and control groups, the simulation group achieved higher proficiency scores overall and had fewer total complications (15 vs 37; p = 0.003) and ureteric injuries (3 vs 9; p < 0.001).⁵

In the realm of robotic surgery, Chu et al. conducted a multicenter study involving 46 surgeons performing VR suturing exercises.⁶ They found that VR suturing skills differed between novices, intermediate, and advanced-level experts, and the VR performance correlated with live robotic surgical performance. Most importantly, there was a correlation between VR performance and live surgical outcomes (i.e., 3-month continence recovery after robotic radical prostatectomy).

Ghazi et al. took consideration of patient-specific variations in simulation.⁷ They found significant improvements in surgical and patient outcomes when preoperative high-fidelity patient-specific percutaneous nephrolithotomy (PCNL) hydrogel simulations were used. The rehearsal group had significantly reduced fluoroscopy time, percutaneous needle access attempts, complications, and additional procedures. The stone-free rate was higher in the rehearsal group, and a significant remaining stone burden requiring additional procedures was recorded less frequently in the rehearsal group.

These above studies indicate that the role of simulation in urology training is important - it can assess surgical skills, accelerate technique acquisition, be tailored by patient-specific features, and predict post-operative outcomes. Yet the incorporation of simulation in urology training is still in its infancy. Getting high-quality evidence to support the role of simulation is only the start; the subsequent focus should be on refining the design of simulation curricula and seamlessly embedding them into resident training.

New Technology - 3D Printing

3D-printing is one of the most active and innovative areas of urologic simulation with researchers producing both surgical and procedural training models as well as patient-specific models for surgical preparation. Within the last year, physical 3D-printed models have been developed for urologic procedures including cystoscopy/ureteroscopy with kidney stone removal, trans-anal prostate biopsy, anatomical endoscopic enucleation of the prostate, and percutaneous kidney puncture.^8–15 In addition, 3D-printed models have also been produced for more invasive procedures such as robot-assisted kidney transplant and renal cell carcinoma resection.¹⁶ In particular, Ghazi et al. and Kho et al. utilized printing materials which closely mimic mechanical properties of urogenital tissues, to approximate the experience of operating on a live person.^10,11 On the pre-operative planning front, Melnyk et al. have rendered and 3D-printed patient-specific models from CT scans for robot-assisted partial nephrectomy (RAPN) and percutaneous nephrolithotomy (PCNL). RAPN models were within 2.5 mm of original patient anatomical geometry and within 5 mm of original patient anatomical alignment; PCNL models were within 2.5 mm of the anatomical pelvicalyceal system and original stone placement and within 15 mm of original alignment.¹⁷ McCabe et al. also developed perfusable 3D-printed models for rehearsal operations of robot-assisted transplant nephrectomy.¹⁸ Additionally, assessment tools for pre-surgical planning have been developed to evaluate the utility and applicability of 3D-printed models.¹⁹ Innovations in 3D-printing continue to be crucial to developing the next generation of urologists and improving patient outcomes.

New Technology – Telestration

Telestration in surgery is the real-time delivery of verbal and visual feedback overlaid on a training surgeon’s field of view by a simulated visual mechanism.²⁰ This has brought an exciting application in the field of urologic surgery, particularly in minimally-invasive training environments. Felinska et al. explores the impact of a telestration system with augmented reality on surgical performance and gaze behavior during minimally invasive surgery (MIS) training.²¹ The system displayed hand gestures in real-time on the laparoscopic screen to provide visual expert guidance. The study found that telestration significantly improved gaze latency, gaze convergence, and collaborative gaze convergence, resulting in fewer errors in tasks and higher performance scores for laparoscopic cholecystectomy. Similarly, Müller et al. developed a neural network capable of segmenting the training surgeon’s hand gestures and displaying them on the trainee’s console screen with the hope of providing real-time visual feedback via augmented reality while in the operating room.²² Piana et al. have expanded the idea of telestration to be any form of computer assisted surgery. They have developed an augmented reality model capable of identifying atherosclerotic plaques in the iliac vessels and proposing a vessel clamping strategy for robot-assisted kidney transplant which was successfully used for intraoperative planning in the OR.²³

Innovation in Simulation for Urologic Procedures

The broadest arm of simulation application in urology is the teaching of procedures and surgical techniques to training urologists with the ultimate goal of building a robust set of baseline skills before performing complex tasks on live patients. Modern surgical training necessitates the use of simulation tasks for both technical and non-technical skills acquisition, particularly in the age of robotic surgery where a whole new teaching style and skill set need to be learned.^2,24 Previously, we discussed innovations in 3D-printed models for procedural training, but these models are often costly and are not reusable long-term. We will now focus on innovations across other simulation platforms such as virtual reality, serious gaming, and animal models for surgical tasks.

Virtual reality (VR) is the use of computers and video screens to simulate specific situations, and there are a wide variety of innovations in VR simulation in the field of urology.²⁵ Recent innovations have specifically integrated urologic instruments with a virtual reality interface. For instance, Cepek et al developed a VR-based endoscopic simulator for urogenital tract procedure training such as bladder scans, bladder tumor ablation, kidney stone ablation, and kidney stone capture and removal.²⁶ Moore et al produced a similar VR simulator for trans-urethral resection of bladder tumor.²⁷ Lampotang et al. introduced a VR simulator for trans-anal prostate biopsy which simulates ultrasound-guided needle placement as well as providing 3D rendering of needle placements. Novice trainees decreased needle deviations from 13.4 ± 8.9 mm to 8.7 ± 6.6 mm (P<0.001).²⁸ As an extension of VR, van der Leun et al. demonstrated that video review of trainee and expert VR simulation in the middle of a VR training exercise significantly reduced tissue injury in the simulation.²⁹ Finally, Covicau et al. presented a VR simulator for training of docking and undocking of the surgical robot, skills necessary for correct position before surgery or undocking during an intraoperative emergency.³⁰

Other studies have explored the application of serious games–or games that are specifically targeted to increase skill acquisition–to performance of VR surgical simulators. Multiple groups have shown that playing serious games and spending time in surgical simulation labs, both under the supervision of expert surgeons or using portable training devices, ultimately improves performance on surgical VR simulation tasks.^31–34 However, even with demonstrated high performance on VR simulation tasks, trainees report that the bar to entry in the operating room remains the lack of opportunities to apply their skills in vivo and their relationships with training physicians.³⁵

There have also been recent innovations in animal models in urology. While not as technologically involved as 3D-printing, animal tissues are still the most readily available surrogate for real tissue simulation. Liakos et al. recently developed an animal model using the esophagus-crop junction of a chicken to simulate a stenotic left ureteropelvic junction with novice surgeons reporting high similarity to in vivo pyeloplasty.³⁶ Focusing on non-technical skills, Lusty et al. presented a porcine model for simulating a progressive hemorrhage during laparoscopic partial nephrectomy. Trainees could practice rapid correction of hemorrhage as well as understand the decision making process for opening the abdomen for rapid bleeding control.³⁷

Trends in Assessment for Simulation

One crucial component of high-quality simulation is objective assessment and structured feedback. Numerous assessment tools, both general and procedure-specific, have been crafted.^38–40 Traditionally, the use of these tools necessitates the examination of surgical videos by experts, a process that is labor-intensive and restricts their widespread application in training programs. Research has been conducted outlining more scalable alternative methods for surgical assessment. Through surgical videos, several studies have leveraged machine learning models to accurately assess technical skills..^41,42 Kinematic data has also been used to assess surgical performance, majorly to represent efficiency.^43,44 Besides directly recording kinematics from surgical instruments, kinematics can also be extracted from surgical videos.⁴⁵ However, there is doubt that kinematics alone is enough to appreciate fine skills required for surgery. Verhoeven et al. found that the kinematics of the instruments appear to overlook crucial elements that experts deem valuable in their evaluations, which underscores the significance of surgical video data and the associated understanding of surgical knowledge in conducting comprehensive surgical assessments.⁴⁶ A study by Trinh et al. used both technical skill assessment and instrument kinematics to predict continence recovery after robotic-assisted radical prostatectomy (RARP), and found that technical skills produced better accuracy than the kinematic data when predicting the outcome.⁴⁷ Combining both together, the model achieved the optimal performance, which indicates each dataset contains unique information.

Another emerging method for surgical assessment is by decoding a surgeon’s movement to its most basic units - surgical gestures. Ma et al. discovered that by analyzing the surgical gesture sequence during the nerve-sparing phase of RARP and inputting this sequence into an AI model, patients’ one-year erectile function recovery could be predicted with approximately 75% accuracy.⁴⁸ Another study found that the proportion of gesture usage was correlated with technical skill scores assessed by expert surgeons, which laid the foundation for establishing a bridge to automated objective surgical skill evaluation.⁴⁹

Finally, several papers explored how to best provide feedback based on assessment methods in a simulated environment. Ma et al. conducted a study to provide tailored feedback based on both the most important technical skill domains and kinematic metrics of participants, to accelerate their learning of robotic suturing skills.⁵⁰ The tailored feedback group showed faster improvement in most performance metrics compared to the control group. One limitation of the study is that the feedback was provided one week after the exercise due to logistic reasons. Laca et al. explored the effect of real-time feedback in simulated dissection tasks.⁵¹ Triggers to provide feedback included risky behaviors and actually surgical errors. Feedback was provided through a standardized audio. Eventually, the feedback group had significantly lower error rates and higher technical skill scores in their test round.⁵¹ Future direction includes to automate the trigger to feedback system and provide stratified and more comprehensive feedback to participants.

Simulation in Bootcamps and Urology Curricula

Increasingly, programs are integrating simulation into their bootcamp or regular curriculum, encompassing technical skills, non-technical abilities, and emergency handling.^52–57 Young et al. did a systematic review of surgical simulation bootcamp and identified five pillar principles, include: 1) delivery at the time of transition (eg, 1st to 2nd year urology resident); 2) covering the accepted syllabus; 3) simulation-based modality of delivery; 4) deliberate practice with formative feedback; and 5) 1:1:1 training (1 model: 1 trainee: 1 trainer).⁵⁸ Another emerging way is gamification of simulation curriculum. Moran et al. gamified robotic surgical simulation by dividing volunteer residents into 4 groups and doing head-to-head simulation contest for a total of six rounds.⁵⁹ The team with the best win-loss record was crowned champion. By the end of the league, residents improved their surgical skills significantly. Gamification makes the simulation training less burdensome when surgical residents have overwhelming clinical and extra-clinical responsibilities to balance.⁵⁹

On an association level, the European Association of Urology (EAU) Robotic Urology Section (ERUS) proposed the ‘Robotic Curriculum’ as a comprehensive training framework that addresses all aspects of a robust training program, based on the concept of proficiency-based progression.⁶⁰ ERUS has developed and validated various curriculum for various procedures, with their most recent being the Robot-assisted Radical Cystectomy with Intracorporeal Ileal Conduit.⁶¹

Future Directions and Conclusion

Simulation in urology training and practice is a rapidly-expanding field with the goal of improving the technical and non-technical skills of urology trainees as well as improving patient outcomes. Recent advances in 3D-printing technology and virtual reality have provided high quality, safe, and effective methods to establish a solid foundation of skills to prepare for practice with patients in the clinic. There has also been innovation in the development of assessment tools in simulated environments that can help trainees understand what they are doing wrong and provide them with feedback outlining how to best correct their mistakes. All combined, advances in simulation and assessment are being actively integrated into urology training curricula with the goal of producing highly skilled urologists in the future. We hope to see further advancement of simulation in urology training and the continued adoption of simulation into medical school and residency training programs moving forward.

Key points:

• Simulation technology for urologic surgical training is advancing rapidly with recent innovations in 3D-printed physical models, virtual reality procedural models, augmented reality for surgical feedback, and non-technical skills assessment through situational simulation.

• New assessment tools integrated into simulation environments provide paths for self assessment of skills acquisition as well as opportunities for tailored feedback to be delivered to trainees in real time.

• Urology residency programs and medical schools across the globe continue to see the value in training simulation with a push to further integrate simulation into training curricula.