Presented by: Robert Chang
Lenox Hill Hospital, Northwell Health

Introduction

The ability to detect ureteral stone impaction preoperatively might carry an array of clinical implications. Previous attempts to predict impaction based on CT findings are inherently limited by the lack of a gold standard comparator and rely on unvalidated, single-surgeon estimation of intraoperative impaction. At present, there is no validated definition of impaction and it is unknown to what degree various surgeons would agree on impaction severity given the same case. We sought to investigate surgeon perspectives and variability in estimating ureteral stone impaction based on a curated ureteroscopy video catalog. This was performed with the overarching goal of developing a consensus grading system and gold standard dataset for future investigation of CT-based stone impaction prediction.

Materials

A catalog of 35 primary ureteroscopy cases was created and distributed to a group of fellowship-trained endourologists. All videos featured visual inspection of the surrounding tissue, guidewire passage next to the stone, as possible, and gentle nudging of the stone with the scope to assess its mobility. Without any predefined criteria or pre-rating discussion, participants were asked to independently rate the degree of impaction on 2 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 intra-rater agreement across both rating systems was evaluated. For categorical ratings, strong agreement between raters was defined as at least 70% majority.

Results

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35 videos were initially rated by 13 surgeons and 11/13 performed second pass ratings. There was a significant amount of inter- and intra-rater variability in assessing stone impaction. Second pass video reviews tended to receive higher severity ratings. Only 13/35 videos had strong agreement (>70%) on degree of impaction (6 none, 7 severe) and only 2 of these 13 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 1 vote for each of the 4 severity categories, indicating stark disagreement between surgeons on what constitutes impaction.

Conclusion

There is significant variability amongst endourologists regarding the definition and the severity of stone impaction. When strong agreement occurs, it is in determining whether a stone is severely impacted or not at all. While the clinical significance of impaction on patient outcomes is yet to be determined, these initial findings suggest further work is needed to expound on the definition of impaction, including standardized endoscopic criteria. Moreover, a tripartite classification system may be the most appropriate manner of grouping ureteral stones on the basis of impaction.

Funding

None. 

Co-Authors

Gregory Mullen,
Northwell Health

Ray Khargi,
Mount Sinai School of Medicine

Tareq Aro,
Northwell Health

Alan Yaghoubian,
Mount Sinai School of Medicine

Mantu Gupta,
Mount Sinai School of Medicine

William Atallah,
Mount Sinai School of Medicine

Dima Raskolnikov,
Montefiore Health

Alexander Small,
Montefiore Health

Christopher Hartman,
Northwell Health

Christian Tabib,
Northwell Health

David Hoenig,
Northwell Health

Zeph Okeke,
Northwell Health

Arthur Smith,
Northwell Health

Arun Rai,
Northwell Health

Jared Winoker,
Lenox Hill Hospital, Northwell Health