The advantages of RAS include a 10-fold magnified 3D field of view, which allows detailed organ observation and sensitive surgical manipulation as the extremely flexible forceps can reflect the surgeon’s movements in real time.16, 17 Additionally, robust image stabilization can inhibit the inadvertent movement of the forceps, making it possible to operate safely, even for elderly surgeons. However, surgical robots have a very different operating system than conventional laparoscopic surgery, and without adequate training in their operation, dangerous operations can lead to severe complications.2 Particularly, since the da Vinci robot does not have tactile feedback, the possibility of severe tissue damage cannot be ruled out if the forceps are moved outside the field of view.18 Therefore, it is strongly recommended that sufficient time for adequate training is given before the start of surgery to ensure safe surgical procedures are performed.4
Since the da Vinci robot produces a 3D image, there is the potential for unusual motion sickness fatigue when the surgeon operates the system. Motion sickness may occur during VR simulator training and during actual surgical operations, and surgeons sometimes complain after using the robot. The mechanism of the onset of motion sickness is not well understood, but the theory of sensory discrepancy is considered as the main one.19 It is hypothesized that a disparity between the vestibular, visual, and somatosensory senses’ experience and the actual senses confuses spatial perception, excites the sympathetic nervous system, and causes motion sickness symptoms. In particular, viewing 3D images using binocular stereopsis often causes unpleasant symptoms, such as headache, vomiting, and eyestrain, depending on the viewing conditions. Ataxia has also been reported in the case of motion sickness due to VR simulators.20 Humans perceive 3D images by adjusting radiation and the crystalline lens simultaneously. The 3D images are composed of incredible pictures in which the gaze is fixed, ignoring the output adjustment. There is no report on what kind of motion sickness is induced by the da Vinci robot operation with 3D images.
Our study presents with several notable findings. First, we observed a significant improvement in the manipulation time for the students who were trained with a VR simulator. Therefore, the VR simulator was useful for improving the RAS technique even for students without surgical experience. Second, we found that motion sickness worsened after the training according to the VAS and T-SSQ scores. On the other hand, continuous training with the VR simulator reduced motion sickness caused by 3D manipulation. In summary, practice with the VR simulator could not only improve the technique of the operation but also improve the student’s fatigue because of the process of the da Vinci robot.
When we evaluated the subscores of the SSQ, training with a VR simulator exacerbated nausea (N-SSQ), oculomotor (O-SSQ), and disorientation (D-SSQ) scores. Furthermore, the O-SSQ score post-training improved significantly with repeated practice. The N-SSQ and D-SSQ scores post-training, however, did not improve after a short training period. Therefore, oculomotor strain improved with repeated training, but nausea and disorientation did not improve with repeated practice. In addition, the N-SSQ score showed little difference before and after training on the same day; therefore, training with the VR simulator may not induce nausea.
With the increase in the number of RASs in recent years, students have more opportunities to be exposed to RAS.21,22 The benefits of exposing medical students to RAS and the simulators are substantial.23 Medical students can fully learn the latest technologies that are becoming mainstream in surgery. They will also be able to provide more appropriate information to their patients when they become doctors. Moreover, it can lead to increased motivation for the new generation of surgeons. Therefore, we believe that training medical students with VR simulators is important for medical education. In fact, the medical students who participated in this program stated that they would like to become experts in RAS in the future.
This study has some limitations. First, the number of subjects was small so further investigation with a larger sample size is required. However, education programs were limited by the COVID-19 pandemic, so we could not accumulate enough samples. Second, we conducted a study of students with no prior surgical experience. Further research is needed to determine whether motion sickness is similar in inexperienced versus experienced surgeons. Additionally, this training session lasted only 5 days, and it would be desirable to investigate schedules further. Despite these limitations, the significant improvement in motion sickness after using the VR simulator repeatedly, showed its usefulness in terms of reducing motion sickness.