Comparison of Summative Temporal Bone Dissection Scales Demonstrate Equivalence

Introduction  Temporal bone surgery is a unique and complicated surgical skill that requires extensive training. There is an educational requirement to maximize trainee experience and provide effective feedback. Objective  We evaluate three temporal bone dissection scales for efficacy, reliability, and accuracy in identifying resident skill during temporal bone surgery. Methods  Residents of various skill levels performed a mastoidectomy with posterior tympanotomy on identic 3D-printed temporal bone models. Four blinded otologic surgeons evaluated each specimen at two separate intervals using three separate dissection scales: the Welling Scale (WS), the Iowa Temporal Bone Assessment Tool (ITBAT), and the CanadaWest Scale (CWS). Scores from each scale were compared in their ability to accurately separate residents by skill level, inter- and intrarater reliability, and efficiency in application. Results  Nineteen residents from 9 postgraduate programs participated. Assessment was clustered into junior (postgraduate year or PGY 1, 2), intermediate (PGY 3) and senior resident (PGY 4, 5) cohorts. Analysis of variance (ANOVA) found significant differences between cohort performance ( p  < 0.05) for all 3 scales considering the PGY level and the subjective account of temporal bone surgical experience. The inter-rater reliability was consistent across each scale. The intrarater reliability was comparable between the CWS (0.711) and the WS (0.713), but not the ITBAT (0.289). Time (in seconds) to complete scoring for each scale was also comparable between the CWS (42.7 ± 16.8), the WS (76.6 ± 14.5), and the ITBAT (105.6 ± 38.9). Conclusion  All three scales demonstrated construct validity and consistency in performance, and consideration should be given to judicious use in training.