Abstract
The objectives of this study are to develop prediction models for total laser energy (TLE) in order to infer surgical time and assist operative planning of intrarenal low-power Ho:YAG laser lithotripsy, and to predict the fragmented volume as well as the stone-free status (SFS). A retrospective review was performed, comprising all single surgeon standardized retrograde intrarenal surgery and low-power Ho:YAG laser lithotripsy at a tertiary care centre between October 2014 and September 2019. Automated measurement of stone volume and stone density (MSD), measured in Hounsfield units (HU), was employed in both pre- and post-operative non-contrast-enhanced computed tomography (NCCT), using a standardized technique on Osirix Lite® software. SFS was defined as complete absence of stone fragments, or fragments < 0.1 cm on meticulous inspection at the end of the procedure, and residual stone burden < 0.0005 cm3 on postoperative NCCT at 3 months. Statistical analysis was performed using the STATA® version 13.1 software for regression models. A p value < .05 was considered statistically significant. A total of 100 patients met the inclusion criteria, requiring a median of 22.3 kJ/cm3 (13.4–36.0) and resulting in a SFS of 41% at 3 months. In a multivariate analysis, according to stone composition, predicted TLE is equal: for uric acid (UA), 11.17 × volume(cm3) + 0.17 × MSD(HU) + 7.48 kJ; for mixed stones, 11.17 × volume(cm3) + 0.17 × MSD(HU) + 6.26 kJ; for calcium oxalate monohydrate (CaOM) stones, 11.17 × volume(cm3) + 0.17 × MSD(HU) + 1.14 kJ; and for calcium phosphate (CaPh) stones 11.17 × volume(cm3) + 0.17 × MSD(HU) − 1.94 kJ. Predicted fragmented volume is equal to 0.93 × volume(cm3) cm3. The significant predictors for SFS were UA stones, the presence of multiple stones, and lower TLE. In clinical practice, our models for intrarenal low-power Ho:YAG laser lithotripsy indicate that larger, denser, and UA stones are associated to higher TLE, and that single and UA stones are more commonly associated to SFS. Since higher TLE means longer operative time, when adjusting for laser parameters, our prediction models may help urologists plan surgeries more precisely based on stone characteristics, ultimately optimizing patients’ treatment.
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Software code is available upon request.
Abbreviations
- 95%CI:
-
95% Confidence interval
- Ca:
-
Calcium
- CaOD:
-
Calcium oxalate dehydrate
- CaOM:
-
Calcium oxalate monohydrate
- CaPh:
-
Calcium phosphate
- HoYAG:
-
Holmium:yttrium–aluminium-garnet
- HU:
-
Hounsfield units
- MSD :
-
Mean stone density
- NCCT:
-
Non-contrast-enhanced computed tomography
- OR:
-
Odds ratio
- RIRS:
-
Retrograde intrarenal surgery
- SD:
-
Standard deviation
- SFS :
-
Stone-free status
- SHI :
-
Stone heterogeneity index
- TLE :
-
Total laser energy
- UA:
-
Uric acid
References
Srisubat A, Potisat S, Lojanapiwat B, Setthawong V, Laopaiboon M (2014) Extracorporeal shock wave lithotripsy (ESWL) versus percutaneous nephrolithotomy (PCNL) or retrograde intrarenal surgery (RIRS) for kidney stones. Cochrane Database Syst Rev (11):CD007044
Pierre S, Preminger GM (2007) Holmium laser for stone management. World J Urol 25(3):235–239
Teichman JM, Vassar GJ, Glickman RD (1998) Holmium:yttrium-aluminum-garnet lithotripsy efficiency varies with stone composition. Urology 52(3):392–397
Bres-Niewada E, Dybowski B, Radziszewski P (2014) Predicting stone composition before treatment - can it really drive clinical decisions? Cent European J Urol 67(4):392–396
Worster A, Preyra I, Weaver B, Haines T (2002) The accuracy of noncontrast helical computed tomography versus intravenous pyelography in the diagnosis of suspected acute urolithiasis: a meta-analysis. Ann Emerg Med 40(3):280–286
Cho KS, Jung HD, Ham WS, Chung DY, Kang YJ, Jang WS et al (2015) Optimal skin-to-stone distance is a positive predictor for successful outcomes in upper ureter calculi following extracorporeal shock wave lithotripsy: a Bayesian model averaging approach. PLoS One 10(12):e0144912
Lee JY, Kim JH, Kang DH, Chung DY, Lee DH, Do Jung H et al (2016) Stone heterogeneity index as the standard deviation of Hounsfield units: a novel predictor for shock-wave lithotripsy outcomes in ureter calculi. Sci Rep 6:23988
Ito H, Kawahara T, Terao H, Ogawa T, Yao M, Kubota Y et al (2012) Predictive value of attenuation coefficients measured as Hounsfield units on noncontrast computed tomography during flexible ureteroscopy with holmium laser lithotripsy: a single-center experience. J Endourol 26(9):1125–1130
Pradere B, Doizi S, Proietti S, Brachlow J, Traxer O (2018) Evaluation of guidelines for surgical management of urolithiasis. J Urol 199(5):1267–1271
Molina WR, Marchini GS, Pompeo A, Sehrt D, Kim FJ, Monga M (2014) Determinants of holmium:yttrium-aluminum-garnet laser time and energy during ureteroscopic laser lithotripsy. Urology 83(4):738–744
Black KM, Aldoukhi AH, Ghani KR (2019) A Users guide to holmium laser lithotripsy settings in the modern era. Front Surg 6:48
Vassar GJ, Chan KF, Teichman JM, Glickman RD, Weintraub ST, Pfefer TJ et al (1999) Holmium: YAG lithotripsy: photothermal mechanism. J Endourol 13(3):181–190
Panthier F, Ventimiglia E, Berthe L, Chaussain C, Daudon M, Doizi S et al (2020) How much energy do we need to ablate 1 mm(3) of stone during Ho:YAG laser lithotripsy? An in vitro study. World J Urol 38(11):2945–53
Ofude M, Shima T, Yotsuyanagi S, Ikeda D (2017) Stone attenuation values measured by average Hounsfield units and stone volume as predictors of total laser energy required during ureteroscopic lithotripsy using holmium:yttrium-aluminum-garnet lasers. Urology 102:48–53
Rana RS, Ather MH (2020) Hounsfield units-a significant predictor of lasering time and energy in the management of upper urinary tract stones using holmium: yttrium-aluminum garnet lasers. Int Urol Nephrol 52(9):1637–41
Ventimiglia E, Pauchard F, Gorgen ARH, Panthier F, Doizi S, Traxer O (2021) How do we assess the efficacy of Ho:YAG low-power laser lithotripsy for the treatment of upper tract urinary stones? Introducing the Joules/mm(3) and laser activity concepts. World J Urol 39(3):891–6
Knudsen BE (2019) Laser fibers for holmium:YAG lithotripsy: what is important and what is new. Urol Clin N Am 46(2):185–191
Yamashita S, Kohjimoto Y, Iwahashi Y, Iguchi T, Iba A, Nishizawa S et al (2019) Three-dimensional mean stone density measurement is superior for predicting extracorporeal shock wave lithotripsy success. Int J Urol 26(2):185–191
Keller EX, De Coninck V, Doizi S, Daudon M, Traxer O (2021) What is the exact definition of stone dust? An in vitro evaluation. World J Urol 39(1):187–94
Traxer O, Keller EX (2020) Thulium fiber laser: the new player for kidney stone treatment? A comparison with holmium:YAG laser. World J Urol 38(8):1883–1894
Kuroda S, Ito H, Sakamaki K, Tabei T, Kawahara T, Fujikawa A et al (2018) A new prediction model for operative time of flexible ureteroscopy with lithotripsy for the treatment of renal stones. PLoS One 13(2):e0192597
Finch W, Johnston R, Shaida N, Winterbottom A, Wiseman O (2014) Measuring stone volume - three-dimensional software reconstruction or an ellipsoid algebra formula? BJU Int 113(4):610–614
Ghani KR, Wolf JS Jr (2015) What is the stone-free rate following flexible ureteroscopy for kidney stones? Nat Rev Urol 12(5):281–288
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This retrospective chart review study involving human participants was in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The institutional Human Investigation Committee (IRB) approved this study.
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Marques-Pinto, A., Santos-Reis, C., Castanheira de Oliveira, M. et al. Prediction models of low-power holmium laser effectiveness in renal stone lithotripsy during retrograde intrarenal surgery. Lasers Med Sci 37, 1873–1880 (2022). https://doi.org/10.1007/s10103-021-03445-4
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DOI: https://doi.org/10.1007/s10103-021-03445-4