Culpan M. et al., 2022: Are the current nomograms sufficient to predict shockwave lithotripsy outcomes?

Saturday, 24 December 2022

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Culpan M, Acar HC, Akalin K, Cakici MC, Tufekci B, Gunduz N, Dogan MB, Yildirim A, Atis G.
Department of Urology, Faculty of Medicine, Istanbul Medeniyet University, Istanbul, Turkey.
Department of Public Health, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey.
Department of Urology, Faculty of Medicine, Istanbul Medeniyet University, Istanbul, Turkey.
Department of Urology, Istanbul Goztepe Prof. Dr. Suleyman Yalcin City Hospital, Istanbul, Turkey.
Department of Radiology, Faculty of Medicine, Istanbul Medeniyet University, Istanbul, Turkey.

Abstract

Introduction and objectives: To investigate factors affecting SWL outcomes, validate three current nomograms (Kim JK, Triple D and S3HoCKwave) and compare the predictive ability of the nomograms for SWL outcomes in upper urinary tract stones.

Patients and methods: Medical records of patients with renal and proximal ureteral stones treated with SWL between March 2013 and October 2020 were retrospectively reviewed. Factors affecting SWL success were analyzed with multivariate logistic regression analysis and the three predictive scoring systems compared with the area under the curve (AUC).

Results: A total of 580 patients were included in our study. The overall stone free rate was 61% and 144/580 patients (24.8%) were stone free after one session. In multivariate logistic regression analysis, stone location at upper calyx (OR:2.988; 95%Cl: 1.350-6.612; p = 0.007), middle calyx (OR:3.036; 95%Cl: 1.472-6.258; p = 0.003), and lower calyx (OR:2.131; 95%Cl: 1.182-3.839; p = 0.012), as well as number of stones (OR:1.663; 95%Cl: 1.140-2.425; p = 0.008), maximum diameter of stone (OR:1.156; 95%Cl: 1.098-1.217; p < 0.001) and maximum Hounsfield Unit (OR:1.001; 95%Cl: 1.001-1.002; p < 0.001) were independent risk factors of SWL failure. The AUCs of the Kim JK, Triple D and S2HoCKwave scores for predicting SWL success were 0.678, 0.548, and 0.626 respectively.

Conclusions: Stone location, number, maximal diameter, and maximum HU were independent predictive factors for SWL outcome in the treatment of upper urinary tract stones. Current nomograms, "Kim JK nomogram", "Triple D score" and "S3HoCKwave score" can predict treatment success after SWL, but all of them have poor discrimination according to AUC analysis.
Actas Urol Esp (Engl Ed). 2022 Jul 5:S2173-5786(22)00053-1. doi: 10.1016/j.acuroe.2021.12.012. Online ahead of print. PMID: 35803872.

Comments 1

Hans-Göran Tiselius on Sunday, 25 December 2022 09:30

The scientific question formulated by the authors of this article was if current nomograms are useful for predicting the outcome of SWL. There are probably few surgical methods, other than SWL, for which nomograms are suggested to predict the outcome. Personally, I have never used nomograms or found any value in nomograms despite four decades of experience with SWL. My opinion is that personal experience is much more important than any nomogram.

In this report SWL treatment data were analyzed retrospectively to find important determinants for treatment results. All treatments were carried out with a Siemens Modularis Variostat lithotripter by “two experienced technicians under the guidance of urologists”. Exactly what that means in terms of treatment quality is impossible to know, but one point of concern is that the only pain treatment that was given was 75 mg of diclofenac sodium administered intravenously OR 1 g of paracetamol.

It is problematic that the energy level of applied shockwaves was determined by the tolerance of the patients. This usually means that in some patients the energy might not have been sufficiently high.

Unfortunately, there was no discrimination between what was accomplished for stones in the kidney or ureter. In that regard it is of note that only 25% of the patients were stone-free after one session.

The variables that were found important to discriminate between success and no success were:
Number of stones
Max and min stone diameter
Stone volume
Stone surface area
Mean, max and min HU.
Interestingly SSD did not differ significantly.

The variables included in the three nomograms were as follows:

Subsequently Quadruple D score has been developed by addition of stone location.
The conclusion of this study was that despite some differences between the nomograms, they all had poor discrimination. These findings support my own conclusion that only clinical experience can be used for appropriate selection of patients aiming at optimal treatment result.

Hans-Göran Tiselius

In this report SWL treatment data were analyzed retrospectively to find important determinants for treatment results. All treatments were carried out with a Siemens Modularis Variostat lithotripter by “two experienced technicians under the guidance of urologists”. Exactly what that means in terms of treatment quality is impossible to know, but one point of concern is that the only pain treatment that was given was 75 mg of diclofenac sodium administered intravenously OR 1 g of paracetamol.

It is problematic that the energy level of applied shockwaves was determined by the tolerance of the patients. This usually means that in some patients the energy might not have been sufficiently high.

Unfortunately, there was no discrimination between what was accomplished for stones in the kidney or ureter. In that regard it is of note that only 25% of the patients were stone-free after one session.

The variables that were found important to discriminate between success and no success were:
Number of stones
Max and min stone diameter
Stone volume
Stone surface area
Mean, max and min HU.
Interestingly SSD did not differ significantly.

The variables included in the three nomograms were as follows:
[img]https://www.storzmedical.com/images/blog/Culpa.png[/img]

Subsequently Quadruple D score has been developed by addition of stone location.
The conclusion of this study was that despite some differences between the nomograms, they all had poor discrimination. These findings support my own conclusion that only clinical experience can be used for appropriate selection of patients aiming at optimal treatment result.

Hans-Göran Tiselius

The scientific question formulated by the authors of this article was if current nomograms are useful for predicting the outcome of SWL. There are probably few surgical methods, other than SWL, for which nomograms are suggested to predict the outcome. Personally, I have never used nomograms or found any value in nomograms despite four decades of experience with SWL. My opinion is that personal experience is much more important than any nomogram. In this report SWL treatment data were analyzed retrospectively to find important determinants for treatment results. All treatments were carried out with a Siemens Modularis Variostat lithotripter by “two experienced technicians under the guidance of urologists”. Exactly what that means in terms of treatment quality is impossible to know, but one point of concern is that the only pain treatment that was given was 75 mg of diclofenac sodium administered intravenously OR 1 g of paracetamol. It is problematic that the energy level of applied shockwaves was determined by the tolerance of the patients. This usually means that in some patients the energy might not have been sufficiently high. Unfortunately, there was no discrimination between what was accomplished for stones in the kidney or ureter. In that regard it is of note that only 25% of the patients were stone-free after one session. The variables that were found important to discriminate between success and no success were: Number of stones Max and min stone diameter Stone volume Stone surface area Mean, max and min HU. Interestingly SSD did not differ significantly. The variables included in the three nomograms were as follows: [img]https://www.storzmedical.com/images/blog/Culpa.png[/img] Subsequently Quadruple D score has been developed by addition of stone location. The conclusion of this study was that despite some differences between the nomograms, they all had poor discrimination. These findings support my own conclusion that only clinical experience can be used for appropriate selection of patients aiming at optimal treatment result. Hans-Göran Tiselius

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