In 1993, China began implementing standardized residency training, and by 2013, the C-STRD program was widely available nationwide [13]. The C-STRD program is a key stage in improving the clinical competence of Chinese residents. According to the classic Halstedian paradigm (see one do one, teach one),[14] young surgeons were trained by experienced surgeons to acquire surgical skills. At present, even in very large residency training institutions, the opportunity of hands-on experience in the operating room is still limited and precious, and the Halstedian paradigm is not perfect due to potential patient’s safety issues, training costs and scarce opportunities.[15] Mandatory yet complex techniques such as minimally invasive surgery are known for their steep learning curve, urging the surgical students to train harder and more often. Based on the above, efforts have been made to study surgical simulators to assist the traditional surgical teaching mode in educating the C-STRD students.
In surgical simulation, VR application plays a vital role by increasing simulator fidelity, immersion stats and user experience.[16] A significant advantage of VR in surgery education is to allow patients to stay safe without being exposed to risks in students’ training process.[17] In the current pandemic, VR technologies are necessary for students to gain appropriate expertise without face-face classes, which could bridge the gap between theory and practice.[18] Other advantages of VR platforms are global connectivity, real-time exchanges, lower cost and better convenience of repeat training. The Chinese education system, including medical education, places great emphasis on incorporating educational theories from China and abroad into the educational practice so that the power of VR can be maximized.
To fully use of immersive VR space, we designed an active training schedule,[19] which we call the exploration mode. Applying Vroom’s Expectancy Theory to surgical education, it is crucial student needs to know that each practice counts and will add to their future career success.[12] Indeed, the skills gained through the surgical simulator can be translated into real-world surgical level improvement.[20] In our case, the C-STRD students' performance in the exploration mode did improve after the training. The beauty of the exploration mode lies in the opportunity to fail at any given time without consequences, which develops their independent learning skills.
According to the Skinner’s Reinforcement Theory, repetition and feedback are critical to learning skills.[10] Objective quantification of the students' performance is a must.[21] Traditionally, the assessment of surgical skills was carried out by observation in the operating room, which was time-consuming and lacked objectivity and reliability.[22] The simulator compensates for this limitation by calculating task-based metrics so that the possibility of quantitative measurement of student performance increases.[23] Definition of metric was a variable sampled in the execution of the task, which in our case was task-dependent (completion of the surgical procedure and correctness of the operation), similar to the work of N. Enayati et al..[24] The monitoring of metrics associated to the students’ interaction with the platform can offer reliable objective quantitative measurements on the student’s learning. It is worth noting that compared to the already mature residency evaluation systems in Europe and the United States, China's residency evaluation system is still evolving[25]. It is believed that the powerful educational tools represented by VR can contribute to the scientific evaluation system in C-STRD program.
Previous VR simulator platforms have rarely reported on collaborative training. Considering the collaborative nature of laparoscopic surgery, we believe it is imperative to include the concept of multi-person collaboration in the design. Collaborative training design is also inconsistent with Flander’s Interaction Analysis System,[11] which offers a way for assessing the process of teacher-student interaction. In our setting, after training with senior surgeons, the students’ performances were better than those who trained alone. Mariani et al. suggested that future VR simulator platforms should evaluate the platform’s impact on training situations under subjective expert guidance,[14] and we are approaching this goal through collaborative design.
Another merit of collaborative design is for students to work on the same procedure as a team, which is broadly accepted as the most effective method to train Nontechnical skills (NTS).[26] NTS were defined as the cognitive (decision-making, situational awareness), social (teamwork, communication, leadership), and personal resources (resilience) that are important in the surgical setting, which is highly valued in the Chinese educational system.[27] In our case, Phase II collaborative group students had better comments than those who trained alone regarding the degree of enjoyment, usability and intention to use the platform. It is possible these positive users’ experiences could turn into NTS. Since surgical incidents may more often be induced by deficits of NTS than deficient technical skills,[28] including situational awareness, decision-making and communication,[16] we should address the importance of collaborative training in surgical education.
VR replaces the physical world with an entire virtual world. It has long been used in many aspects of medicine, like pre-operation evaluation of the patient-specific anatomy in high resolution,[29, 30] post-operative pain management, perioperative stress reduction and relaxation,[31] cancer-related symptoms relieving during chemotherapy.[32] Unlike similar technologies Augmented Reality (AR) and Mixed Reality (MR), which have been used in surgical planning and intraoperative guidance,[33, 34] VR with its immersive character, is more suited for medical training. In a VR medical education study, all the participants believed the VR course was a valuable learning tool for them to gain a more comprehensive understanding of anatomy and surgery,[35] which is inconsistent with our finding that most students thought the VR platform improved their surgical skills and worth learning.
Currently, VR in general surgery is used in two main areas of surgical teaching: robotics and laparoscopy surgery.[36] Most studies were carried out using commercial VR platforms like dV-Trainer Mimic (Seattle, WA, United States) and LapSim VR (Surgical Science, Gothenburg, Sweden). They simulate robotic and laparoscopic surgery, respectively.[37] Several RCTs have demonstrated the ability of LapSim to translate the skills learned from the platform to actual clinical procedures.[38] We developed the VR platform for laparoscopic training because we believe laparoscopic surgery is most suited for VR surgical training. After all, the way of looking at a monitor resembles the actual scene in the operation room where the students look at a monitor while operating the surgical instrument. A similar method of learning is through tablet-simulators, which is also effective in transferring knowledge to real-world tasks.[39]
One of the key technologies to achieve VR immersion is visual rendering. The rendering engine can make the creation and deployment of 3D scenes easier and have gained more attention in the build process of surgical simulators, especially Unity.[40] We use the most reliable "Unity" for the visual rendering of 3D models, which already include all the features necessary to create 3D scenes. After rendering, we use a head-mounted display (HMD), the HTC Vive (HTC Corporation China), to allow students to completely immerse themselves in the virtual world.[41] The advantage of using such HMD lies in the degree of immersion that can be realized. The success of our VR laparoscopy training platform is evidenced by students’ improved scores after training.
Haptic rendering is another critical element of the next generation of VR surgery simulators. Haptic devices guarantee that the students can operate and interact as if they were in the real world.[16] The importance of haptic feedback is mentioned in almost all studies. But just like the Da Vinci surgical robot, most VR platforms have not yet developed haptic feedback. Hence, the tele-operative approach compensates for the absence of haptic feedback with “visual feedback”.[42] In our case, we implemented the real-time tissue deformation program with C# to achieve such visual feedback.
This study has the following limitations. Firstly, the small sample size from single-center may hamper the statistical significance and translational medicine value. To go beyond this pilot study, we need to test the platform with C-STRD students of different levels in the future, as well as study whether the training effects have a direct correlation with clinical outcomes such as reduction of operating time or blood loss. Secondly, the main reason for the students' negative evaluation of the platform's usability was that the HTC VIVE control devices were different from real clinical instruments, which takes time to adapt. Currently, there are no such commercially available haptic feedback devices specially made for surgical education. It is necessary to develop surgery-specific haptic feedback devices which resemble surgical instruments. Thirdly, the current version as a prototype could not enable remote collaborative surgery. In the future, we plan to achieve this goal by operating on a reliable web server.