Discussion
infections, mistakes
INFECTIONS, COMPLICATIONS
In this prospective randomized study, we taught mastoidectomy to 30 volunteer medical students with two training methods (VR and traditional) and assessed their performance using multiple subjective and objective metrics related to mastoidectomy performance. We recruited medical students without any prior experience in mastoidectomy to ensure comparable initial conditions regarding the participants’ surgical skills and knowledge. To our knowledge, this is the first prospective and randomized study to evaluate the feasibility of utilizing a 3D anatomical model in VR for training mastoidectomy without the inclusion of VR simulator training. Our goal was to explore whether VR training steepens the learning curve of mastoidectomy and if it could be utilized as a complementary method in future surgical training.Overall, the participants rated the VR training method better than the traditional method. Consistent with previous research, the differences were most notable when considering 3D perception which was often regarded as the strength of the VR method and weakness of the TT method. Understandably, this is the clear advantage of a fully 3D model over the 2D printed images seen in the anatomy books. The individual categorical scores for both methods decreased after the mastoidectomy. This seems to indicate that in retrospect the participants felt the training did not match the real world as well as they initially thought. Despite that, the mean overall grade given for the VR method did not decrease in the second evaluation which is in clear contrast with the TT method.Disadvantages most often reported by the VRT group were the lack of colours and soft tissues in the model, small problems with the equipment and the view (such as a difficulty to achieve a sharp picture) as well as the difficulty of understanding the real proportions of the structures. In the future it is likely that technical advancements can amend at least some of these concerns.Even though the VRT group required less assistance during the operation, they were not faster nor was their outcome better than the TT group and they made a similar number of mistakes. We expected that a possible increase in understanding of the mastoidectomy prior to drilling would reflect in the number of assistance requests, operational time and the number of mistakes as well as the outcome. Based on our results this was not the case and it is unclear whether the difference in the amount of assistance needed reflects better knowledge obtained. The numerous injuries observed here could point to insufficient ability to identify and understand where the critical structures are or that the technical skills were not adequate for the task. Of course, there is still the possibility that one of the methods gave a superior understanding of the anatomy and the procedure, but the participants did not have the technical skills to match that.To holistically understand each participants’ performance, a non-weighted composite variable was created based on the operational time, the amount of assistance needed and the Welling score. These variables were chosen as a simplified indication of a successful surgery as an experienced surgeon should be able to perform a routine procedure in a timely manner, without any help and with excellent results. Evaluating surgical performance based on operational time and technical adequacy is supported by current data. For example, longer operational times have been shown to increase the risk of surgical infections and other complications leading to a worse outcome for the patient [Our findings show that the VR method did not seem to significantly overcome the traditional training methods. At the same time, there were no notable advantages for the traditional methods either. It is also clear that the participants preferred the VR method over the traditional books and this aspect should be accounted for in the future development of mastoidectomy training. These results are in line with previous research [While VR is getting more adopted in anatomy training, evaluation of its outcomes and effectiveness in previous studies have been limited to written exams instead of a simulated procedure [The clear strength of our study is the randomized and prospective approach together with the inclusion of the many different metrics of performance and methods proposed in the literature and combining them all together in this single study for the first time. While our sample size remains quite small in absolute terms, it is one of the largest when compared to earlier studies conducted on similar subjects. Our study is also the first one to explore the usage of VR for purely anatomical and theoretical training of mastoidectomy without the need for a more costly VR simulator. A recent meta-analysis on VR simulators in temporal bone surgery shows promising results for simulator training [Further research will focus on study replication in a typical training situation with the repeated training sessions and increased sample size of residents. In this study, the surgical training was conducted after only a single instruction session. Repeated instruction and surgical sessions might reveal changes in participant’s learning curve over time.In addition, recruiting residents instead of medical students will open new, relevant insights into the use of VR in their training. For example, residents’s initial anatomical knowledge and relevant surgical skills would likely vary within the group and differ greatly compared to the current sample size of medical students.Due to the low number of ENT residents in Finland, it was unfeasible to recruit a sufficient population of residents in this study. Nevertheless, participants with minimal surgical background allowed us to examine the hypothesized benefits of VR, especially in terms of obtaining improved topographical understanding and increased performance in their first mastoidectomy. Although mastoidectomy is undeniably a complex and demanding procedure for a senior resident and even more so for medical students, the selected procedure and training setup provided the recruited participants with additional advantages.Mastoidectomy drilling with 3D-printed bones represented a genuine surgical procedure that provided an authentic yet safe practice ground that could be easily replicated for all participants. In addition, the surgical training was completed in the training center that strongly resembled operating room setting. Taken together, medical students could experience complex surgical training in close-to-authentic conditions and ahead of their potential residency.With respect to the research questions, the complex procedure allowed us to examine impact of VR in the highly authentic tasks, as opposed to traditional, simplified training. The complex training also contributed to research on skill transfer (i.e., how simulation training transfers to authentic operations), which is understudied in the current research on surgical innovations and training. In future work, we will also systematically evaluate participant’s surgical performance with respect to the selected model (i.e., cadaveric and 3D-printed models) and factor in participants’ personal traits and technical skills to examine the impact of training method.Originally, we had planned to also analyse the operational times of the individual steps of the procedure. Due to the dynamic nature of mastoidectomy, these steps were completed in order that varied across participants. To provide the most authentic experience, we did not enforce a particular order of the individual steps such that other performance variables were not compromised. Due to the variable order and the sample size, the analysis of the individual steps would be misleading.In conclusion, the VR method seems to be at least as good as the traditional method when considering the training of a complex and demanding surgical procedure for novices with the added benefit of increased trainee satisfaction.