INTRODUCTION AND OBJECTIVE:The deconstruction of surgery into a semantic vocabulary yields an effective tool for surgical education. Herein, we disassemble tissue dissection into basic maneuvers, then utilize them to compare dissection between experts (E) and novices (N) during robotic renal hilum preparation.METHODS: Videos of robotic renal hilum dissection were manually reviewed. Only cases where the dominant hand uses monopolar scissors were included. Experts were defined by > 100 prior robotic cases, while novices 100 cases. 6 expert surgeons at our center arrived at a consensus for a dissection gestures classification system: blunt dissection (spread, peel/push, hook), sharp dissection (cold cut, energy cut and burn), and combination gestures (pediclize [ multiple peels, hand over hand [ both hands push) (Fig 1a). Continuous variables were compared by Mann-Whitney U test, and categorical variables by Chi-square test. RESULTS: 19 hilar dissections with 3,179 dissection maneuvers were analyzed, representing 11 cases from 6 expert surgeons (median 1750, range [150-3500] cases) and 8 cases from 6 novices (median 80 [5-100] cases). Patient baseline variables were comparable (p > 0.05). Compared to novices, experts were more efficient completing the artery preparation (E 32 vs N 83 gestures, p [ 0.004) (Fig 1b). Experts needed less retraction adjustments (E 26 vs N 55 gestures, p [ 0.047) and utilized more hand over hand gestures (5 vs 1 counts, p [ 0.005). During artery preparation, they used more proportion of hook (E 15.7% vs N 6.4%, p<0.001) and burn (E 24.1% vs N 10.7%, p<0.001) (Fig 1c). Experts were more efficient with spread (E 2.71 vs N 2.96 s/gesture, p [ 0.028) and hook (E 2.20 s vs N 2.50 s/gesture, p [ 0.05), but spent more time with peel/push (E 1.73 vs N 1.44 s/gesture, p<0.001), energy cut (E 2.28 vs 1.50 s/gesture, p<0.001) and pediclize (E 4.05 vs 2.92 s/ gesture, p<0.001). Overall, surgeons spent more time with peel/push (1.58 vs 1.41 s/gesture, p<0.001) and hook (2.79 vs 1.23 s/gesture, p<0.001) around the vein vs artery.CONCLUSIONS: This dissection gesture classification system can disassemble the renal hilum preparation. We found differences in dissection patterns of experts vs novices. This novel comprehensive classification may help streamline surgery education.