Endoscopic Evaluation of Ureteral Stone Impaction Highlights Significant Variability in Definitions Between Endourologists.

Previous studies attempting to predict impaction on CT have relied on various criteria without a gold standard for comparison. Intraoperative single-surgeon estimations of impaction have been unvalidated and subjective. This study aimed to investigate surgeon perspectives and variability in estimating ureteral stone impaction based on a curated ureteroscopy video catalog. A catalog of 35 primary ureteroscopy cases was distributed to a group of fellowship-trained endourologists. All videos featured visual inspection of tissue around the stone, attempted passage of a guidewire adjacent to the stone, and an attempt to dislodge the stone with gentle nudging of the scope. Participants independently rated impaction on two different scales: continuous (0-9) and categorical (none/mild/moderate/severe). After a first pass, participants rated the videos in a new, random order. Inter- and intrarater agreement across both rating systems was evaluated. In total, 35 videos were evaluated by 13 endourologists. Overall, 13/35 videos had strong agreement (>70%) on the degree of impaction (6 none, 7 severe), and only 2 of these had 100% agreement (1 none, 1 severe). Continuous scale ratings mirrored the categorical ratings for the none and severe impaction cases. There were no cases with consensus agreement of mild or moderate impaction. More than one-third (12/35) of videos had at least one vote for each of the four severity categories, indicating stark disagreement between surgeons on what constitutes impaction. There is significant variability among endourologists regarding the definition and severity of stone impaction. When strong agreement occurs, it is when a stone is deemed to be severely impacted or not impacted. Further work is needed to create a standardized definition of impaction based on objective endoscopic criteria. A tripartite classification system may be the most appropriate manner of grouping ureteral stones based on impaction.