Background: As an integral part of computer-assisted surgery, virtual surgical planning (VSP) leads to significantly better surgery results, such as for oral and maxillofacial reconstruction with microvascular grafts of the fibula or iliac crest. It is performed on a 2D computer desktop screen (DS) based on preoperative medical imaging. However, in this environment, VSP is associated with shortcomings, such as a time-consuming planning process and the requirement of a learning process. Therefore, a virtual reality (VR)–based VSP application has great potential to reduce or even overcome these shortcomings due to the benefits of visuospatial vision, bimanual interaction, and full immersion. However, the efficacy of such a VR environment has not yet been investigated. Objective: This study aimed to demonstrate the possible advantages of a VR environment through a substep of VSP, specifically the segmentation of the fibula (calf bone) and os coxae (hip bone), by conducting a training course in both DS and VR environments and comparing the results. Methods: During the training course, 6 novices were taught how to use a software application in a DS environment (3D Slicer) and in a VR environment (Elucis) for the segmentation of the fibula and os coxae, and they were asked to carry out the maneuvers as accurately and quickly as possible. Overall, 13 fibula and 13 os coxae were segmented for each participant in both methods (VR and DS), resulting in 156 different models (78 fibula and 78 os coxae) per method (VR and DS) and 312 models in total. The individual learning processes in both environments were compared using objective criteria (time and segmentation performance) and self-reported questionnaires. The models resulting from the segmentation were compared mathematically (Hausdorff distance and Dice coefficient) and evaluated by 2 experienced radiologists in a blinded manner. Results: A much faster learning curve was observed for the VR environment than the DS environment (β=.86 vs β=.25). This nearly doubled the segmentation speed (cm3/min) by the end of training, leading to a shorter time (P<.001) to reach a qualitative result. However, there was no qualitative difference between the models for VR and DS (P=.99). The VR environment was perceived by participants as more intuitive and less exhausting, and was favored over the DS environment. Conclusions: The more rapid learning process and the ability to work faster in the VR environment could save time and reduce the VSP workload, providing certain advantages over the DS environment.

Background: Although surgical suturing is one of the most important basic skills, many medical school graduates do not acquire sufficient knowledge of it due to its lack of integration into the curriculum or a shortage of tutors. E-learning approaches attempt to address this issue but still rely on the involvement of tutors. Furthermore, the learning experience and visual-spatial ability appear to play a critical role in surgical skill acquisition. Virtual reality head-mounted displays (HMDs) could address this, but the benefits of immersive and stereoscopic learning of surgical suturing techniques are still unclear. Material and methods: In this multi-arm randomized controlled trial, 150 novices participated. Three teaching modalities were compared: an e-learning course (monoscopic), an HMD-based course (stereoscopic, immersive), both self-directed and a tutor-led course with feedback. Suturing performance was recorded by video camera both before and after course participation (>26 h of video material) and assessed in a blinded fashion using the Objective Structured Assessment of Technical Skills (OSATS) Global Rating Score (GRS). Furthermore, the optical flow of the videos was determined using an algorithm. The number of sutures performed was counted, the visual-spatial ability was measured with the Mental Rotation Test (MRT), and courses were assessed with questionnaires. Results: Students’ self-assessment in the HMD-based course was comparable to that of the tutor-led course and significantly better than in the e-learning course (P=0.003). Course suitability was rated best for the tutor-led course (x̄=4.8), followed by the HMD-based (x̄=3.6) and e-learning (x̄=2.5) courses. The median ΔGRS between courses was comparable (P=0.15) at 12.4 (95% CI 10.0–12.7) for the e-learning course, 14.1 (95% CI 13.0–15.0) for the HMD-based course, and 12.7 (95% CI 10.3–14.2) for the tutor-led course. However, the ΔGRS was significantly correlated with the number of sutures performed during the training session (P=0.002), but not with visual-spatial ability (P=0.615). Optical flow (R ²=0.15, P<0.001) and the number of sutures performed (R ²=0.73, P<0.001) can be used as additional measures to GRS. Conclusion: The use of HMDs with stereoscopic and immersive video provides advantages in the learning experience and should be preferred over a traditional web application for e-learning. Contrary to expectations, feedback is not necessary for novices to achieve a sufficient level in suturing; only the number of surgical sutures performed during training is a good determinant of competence improvement. Nevertheless, feedback still enhances the learning experience. Therefore, automated assessment as an alternative feedback approach could further improve self-directed learning modalities. As a next step, the data from this study could be used to develop such automated AI-based assessments.

Purpose: Significant vasovagal reaction is one of the untoward events in the course of simple extractions. The present study then aimed to record the patients’ heart rate during the extraction procedure. Materials and methods: Informed consents were obtained in advance. Patients were placed in the dental chair and their heart rate was measured before /and prior to the anesthetic injection, during, and after dental extraction on a pulse oxymeter device. Data were analyzed using paired t-test. Results: Sixty one patients were included. The mean heart rates of these patients prior, during, and after extraction were 88, 86 and 81, respectively. Two by two comparisons showed a significant decrease in the mean heart rate during extraction compared to the baseline and also after extraction compared to both before and during extraction (p < 0.05 for all three). Conclusions: Despite the presence of sufficient local anesthesia and performing the extraction with the least trauma, a significant decrease in heart rate is evident.