Presentation Authors: Kevin Koo*, Tareq Aro, Sunghwan Lim, Doru Petrisor, Dan Stoianovici, Brian Matlaga, Baltimore, MD
Introduction: Accurately estimating fragment size is an important task during ureteroscopic stone management, as it can provide determination of the adequacy of dusting or the ability to retrieve fragments through a ureteral access sheath. We previously reported an ex vivo validation of a novel software that can accurately measure small stone fragments. This study assesses the feasibility of integrating the software into operating room workflow.
Methods: Mock stone fragments were selected to mimic a variety of non-ideal fragmentation conditions. Using a commercial model of the kidney and ureter designed for ureteroscopy training, we performed two versions of a timed basketing task to simulate real-time software measurement. In the conventional version, the ureteroscope was navigated from the UPJ to the stone in a superior pole calyx, then the stone was retrieved with the basket back to the UPJ. In the measurement version, the ureteroscope was again navigated from the UPJ to the stone, then real-time measurement of the stone was performed using the software, followed by stone retrieval to the UPJ. Differences in task completion time and fragment characteristics were compared.
Results: A total of 20 stone fragments were selected with different combinations of internal characteristics: size (mean 7.1 mm, range 3.2-10.3 mm), 3-dimensional shape (50% pyramidal, 30% ovoid, 20% cuboid), surface contour (50% smooth, 50% rough), and planar symmetry (60% asymmetric, 40% symmetric). In the conventional version of the task, mean completion time was 16.5 sec (range 10.1-33.6 sec), compared with a mean completion time of 38.8 sec (range 27.2-60.0 sec) in the measurement version. The additional procedure time required to perform real-time measurement averaged 22.2 sec (range 8.8-42.6 sec). Variation in these times for certain stones was typically due to more challenging planar alignment of the ureteroscope and basket tip, which is required for accurate calculation using the software.
Conclusions: Integrating a novel software for real-time stone measurement during ureteroscopy is feasible and has a modest effect on the time required for stone manipulation. These findings support in vivo trials of the software to enhance clinical decision-making in ureteroscopic stone management.