Setting and participants
This study was conducted as part of a voluntary elective course for medical students in the clinical part of their studies at Heidelberg University. This study took place in the training center for MIS of the Department of General, Visceral and Transplantation Surgery at Heidelberg University Hospital. Only laparoscopically naïve students, i.e., those who had never previously participated in a laparoscopic training course and had less than two hours of laparoscopic experience, were included. They received a standardized, 4-h basic skill training on box and virtual reality (VR) trainers. All participants were informed of the duration, procedures, methods, and objectives of the study before written informed consent was obtained [Sample size was calculated based on data from a pilot study with a comparable setting (All participants were randomized in a 1:1 ratio and assigned to an intervention or control group. Randomization was performed with a block size of 12 using an online tool (In each case, participant characteristics were recorded before training. To become familiar with the laparoscopic setting, all participants underwent the same basic training. In addition, they were asked to answer the validated questionnaires (Questionnaire on Current Motivation (QCM), self-efficacy expectations scale (ASKU), self-assessment of satisfaction with own performance) for further participant characterization [To ensure consistent video-based instruction in the performance of laparoscopic knot tying on the box trainer using C-loop technique, all study participants were shown an error-free instructional video as a mastery model three times [The checklists included the 5-point Likert scale for assessing knot quality [The checklists were available as online questionnaires and each score was recorded. In addition, the time required for each knot was measured. The time limit per laparoscopic knot was 20 min. The proficiency criteria were achieved if at least 4 of 5 points in the Knot Quality Score, 11 of 13 points in the OSATS Procedural Checklist (corresponding to ≥ 80% of the maximum score), and a knot time of max 2:00 min (min:s) were obtained. This matches performance levels achieved by experienced surgeons [