Method:
Eligibility criteria were surgical residency not exceeding the first year of surgical training, a limited experience in MIS and informed consent to the study procedures including an anonymized publication of the study data. Limited experience in MIS was defined as camera navigation in laparoscopic cholecystectomies only.
Fifty residents were enrolled and prospectively randomized to either three months of structured VR- training or no training. Every participant underwent a basic VR- skills assessment and a serial assessment of defined soft skills including self- efficacy, stress- coping and motivation prior to randomization.
Basic VR- skills were measured within seven modules of the VR- simulator LapSim® (Surgical Science, Goteborg, Sweden) including "camera and instrument navigation", "coordination", "grasping", "lifting and grasping", "clip applying" and "diathermy cutting". Each module had to be performed in two levels of difficulty- medium and hard. Means of defined parameters of VR- performance were generated. Defined parameters of VR- performance comprised "time to complete task", "economy of instrument motion" and "tissue damage".
Serial assessment of defined soft skills comprised standardized psychological paper- pencil questionnaires regarding self efficacy (GSE), stress coping (SVF 78) and motivation (QCM).
Participants randomized to the intervention group had to pass sessions of 45 minutes each twice a week for three months. Participants randomized to the control group underwent no training at all.
Three months after randomization, VR- performance was assessed likewise. Outcome measurement of VR- performance defined results derived from the most complex module "diathermy- cutting" as endpoint.
The study was approved by the local ethics committee. Participation of the study was voluntary. Data were blinded to the investigators.
The data were descriptively analysed using SPSS® software version 16.0 (SSPS®, Chicago, Illinois, USA). Spearman regression analysis was performed to correlate means of virtual laparoscopic performance and the results derived from serial psychological testing. The differences between the randomized groups were assessed by means of the non- parametric Mann-Whitney- Test regarding all parameters, laparoscopic performance as well psychological scores. Relation of means was carried out using the two- independent t- Test. The level of statistical significance was set at p < 0.050 (two-tailed).
