The effect of anatomical variation on learning and cognitive load during simulation-based training of mastoidectomy-a randomized, controlled trial.

PURPOSE: To investigate the impact of anatomical variation (AV) on surgical skills acquisition, i.e., learning curves, and cognitive load (CL) during virtual reality (VR) simulation-based training (SBT) of mastoidectomy. METHODS: A randomized, controlled educational trial. Trainees (medical students) were randomized to perform 12 virtual mastoidectomies on anatomically different temporal bones (intervention) or on the same temporal bone (controls). Training was organized as distributed practice. Mastoidectomy performances were evaluated by two blinded raters using the modified 26-points Welling Scale assessment tool and learning curves were established. CL was estimated by secondary task reaction time. RESULTS: The intervention group (AV) improved from baseline performance by 80% compared with 59% in the control group (p = 0.52). The intervention group reached 68%, and the control group of 65% of the maximum performance score. The groups had equal CL at the beginning of training (49% increase in reaction time for the intervention group vs. 47% for the control group). After the training program, CL had decreased by 11.6% and 10% from baseline for the intervention and control group, respectively. CONCLUSION: Anatomical variation in SBT of mastoidectomy neither affected learning curves nor CL of novices compared to repeated practice on the same case. This suggests that AV is not needed for basic skills acquisition in complete novices. Nonetheless, AV and exposure to different anatomical variations could be valuable for more experienced trainees while other instructional designs might be more suitable for novice learners.