This study demonstrated that the new VR simulation system could significantly show differences between the surgeons and non-medical professionals. No statistically significant difference could be demonstrated for GOALS score between the novices and experts, except for one item. However, both bimanual dexterity and total score in the experts were not statistically different, although they tended to be higher than those in the novices. This result revealed that the novel simulator could detect the ability of an operator for surgical dissection.
Some laparoscopic surgical simulators were validated in previous studies, such as the LapSim and LAP Mentor [20,21,22]. They were more valuable as a training tool than an inanimate box trainer [23]. Multiple studies have been conducted to validate VR simulators as tools to train surgeons for laparoscopic skills [9]. Some VR simulators provide haptic feedback and verify the validity of these systems. Haptic, or “force-feedback” technology in VR simulation, is a rapidly developing field. Haptic feedback improves the fidelity, realism, and training effect of VR simulators. Six randomized controlled trials demonstrated that haptic-enhanced VR simulation is significantly more effective than those without haptics for skill training, particularly in novices [24]. Haptic feedback in actual operation is one element of the essential tacit knowledge that surgeons must gain. This knowledge leads to effective and accurate surgical dissection, minimal injury to adjacent organs, and less unnecessary coagulation. To the best of our knowledge, there is no other VR simulator with haptic feedback that attempted to train principles of appropriate traction on the tissue that is needed for surgical dissection.
Few studies have been conducted on training and evaluation of surgical dissection. Matsuda et al. conducted a study on it and, they concluded that motion analysis of surgical performance, such as dissection, is a powerful tool for basic skill assessment [17]. By measuring instrument tip force, Yoshida et al. found that applying a vertical force first, followed by a horizontal force with minimal vertical force, was an effective and safe method for surgical dissection [25]. However, these surgically haptic cues have not been reproduced and practiced in any training simulator.
It is challenging to evaluate surgical skills objectively. Previous studies reported validated simulator metrics, including time taken, the total number of movements, and total path length, which were objectively evaluated by specific systems in a simulator [7, 23, 26, 27]. They are useful and easy to assess by simulators. However, these metrics are summative to assist trainees in developing a concrete understating of their technical skills. Alternatively, there are global rating scales for intraoperative technical skills such as GOALS, objective structured assessment of technical skill, and operative performance rating scale. In this study, GOALS was used in evaluation, which was developed to fulfill the need for objectively quantifying surgical skills in LS. Hogle et al. demonstrated that GOALS was able to differentiate novice fellows from graduating fellows [28].
The VR simulator was designed to focus on one procedural scene in laparoscopic sigmoid colectomy. The scene is the medial meso-sigmoid dissection. Owing to the oncologic safety concerns of laparoscopic colorectal surgery (LCS), the dissemination of this technique has been slow [29]. However, surgical access remains poor for residents in LCS, as primary operators [30]. Several studies have assessed the simulation for basic laparoscopic skills and procedures. They suggested a remarkable lack of available data on the educational value of simulated training in advanced LS, such as LCS, exists [31]. The VR simulator was directed to surgical dissection, which is one of the most basic surgical skills. This could be practical training for LCS.
Today, the coronavirus disease 2019 pandemic has severely impacted healthcare systems worldwide. In addition, it has forced surgical residents to expose fewer surgical cases by redeploying intensive care and emergency and reducing elective surgical cases [32]. With a stunning reduction in operative exposure, it is challenging for surgical trainees to improve their surgical skills and knowledge. Owing to this, surgical simulators, such as the VR simulator, have the enormous potential to increase the opportunity for training instead of an actual operating theater.
Differences between the novices and experts were not statistically significant except for one item, which was efficiency. This result could reflect less sensitivity in “tissue handling” in the present simulator. The non-medical professionals received a high score of 4 (3.25–4) in tissue handling, although their scores for other items were lower than this. In a previous study, which was evaluated by GOALS, tissue handling and depth perception were not statistically significant. The learning curve in tissue handling reached a plateau at a low level in the literature [28]. It may imply the difficulty in assessing a skill of tissue handling according to GOALS. This can also explain that the study could not prove the significant difference in the total score between the novices and experts. Their scores are very near in each item.
This study had several limitations. First, the study was performed in a single center. Although this was enough to indicate a statistical significance between the non-medical professionals and surgeons, a large sample size is recommended. Second, although the assessment was performed by three laparoscopic experts after discussing and reaching a certain consensus on the evaluation of GOALS score, and the GOALS score was well-validated and showed good interrater reliability, the interrater reliability was not analyzed in this study. Third, the variability in gender was not accounted for and could have affected the outcomes. All of the non-medical professionals were female, whereas all of the surgeons were male. Fourth, we utilized incomplete GOALS score for evaluation. However, we excluded one out of five items, which was autonomy, because this task could not evaluate autonomy in the participants.