Evaluation of a free 3D software for kidney stones' surgical planning: "kidney stone calculator" a pilot study
World J Urol . 2021 Mar 29;1-8. doi: 10.1007/s00345-021-03671-z. Online ahead of print.
Frédéric Panthier, Olivier Traxer, Laurent Yonneau, Thierry Lebret, Laurent Berthe, Lounès Illoul, Marc-Olivier Timsit, Arnaud Mejean, Steeve Doizi, François Audenet
Introduction: Kidney Stone Calculator (KSC) is a free, three-dimensional (3D) planning software for flexible ureteroscopy(fURS) with Holmium:YAG(Ho:YAG) endocorporeal lithotripsy (EL). KSC provides the stone volume (SV) and expected duration of lithotripsy (ExDL) estimations based on non-enhanced-CT scan (NECT) DICOM series. We aimed to provide a preclinical and clinical evaluation of KSC.
Patients and methods: A preclinical evaluation measured the SV by three operators (resident, endourology expert and research engineer) among 17 NECT cases. Between January and March 2020, a multicentric, prospective, observational double-blind clinical evaluation was conducted in patients presenting with renal stones treated with Ho:YAG-EL during fURS and preoperative NECT. Demographic and surgical data were collected. The primary endpoint was a significant median difference between ExDL and EffectiveDL (EfDL). Second, efficiency (J/mm3) and efficacy (mm3/min) ratios were calculated.
Results: The preclinical evaluation showed no significant difference in the SV measurements among operators (p > 0.05). Pearson and Kendall coefficients of 0.99 and 0.98, respectively, were found. Twenty-six patients were included in the clinical evaluation, with a median age of 55 years. In 66% of cases, there was a single stone located in the lower pole, with a density > 1000 Hounsfield Unit observed in 42% and 85% of cases. A 14% [Q1-Q3 (5.4-24.8); p = 0.36] median difference between ExDL and EfDL was noted, which was greater in the case of lower pole stones with no possible relocation (p = 0.008). Median values of 17.6 J/mm3 and 0.4 (0.32-0.56) mm3/s EL were also noted.
Conclusions: Kidney Stone Calculator is a reproducible and accurate software that allows for an estimation of the stone burden and provides an ExDL for URSf. Defining the influencing factors of EL will improve its ExDL.
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