Yin X. et al., 2023: Development and validation of a predictive model for stone-free failure after extracorporeal shockwave lithotripsy in patients with ureteral stone in a large prospective cohort
Yin X, Li J, Pan C, Liu G, Li Z, Bai S.
Department of Pediatric Urology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China.
Department of Urology, Shengjing Hospital of China Medical University, 36 Sanhao Street, Shenyang, 110004, Liaoning, People's Republic of China.
Department of Urology, Shengjing Hospital of China Medical University, 36 Sanhao Street, Shenyang, 110004, Liaoning, People's Republic of China.
Department of Urology, Shengjing Hospital of China Medical University, 36 Sanhao Street, Shenyang, 110004, Liaoning, People's Republic of China.
Abstract
Purpose: To develop and validate a nomogram for predicting stone-free failure after shock wave lithotripsy (SWL) guided by ultrasound in patients with ureteral stones.
Methods: The development cohort consisted of 1698 patients who underwent SWL guided by ultrasound at our center from June 2020 through August 2021. Multivariate unconditional logistic regression analysis was used for building a predictive nomogram with regression coefficients. An independent validation cohort consisted of 712 consecutive patients from September 2020 through April 2021. The performance of the predictive model was assessed in regard to discrimination, calibration, and clinical usefulness.
Results: Predictors of stone-free failure included distal stone location (odds ratio = 1.540, P < 0.001), larger stone size (odds ratio = 1.722, P < 0.001), higher stone density (odds ratio = 1.722, P < 0.001), larger skin to stone distance (SSD) (odds ratio = 1.058, P < 0.001), and higher grade of hydronephrosis (odds ratio = 1.755, P = 0.010). For the validation cohort, the model showed good discrimination with an area under the receiver operating characteristic curve of 0.925 (95% confidence interval, 0.898, 0.953) and good calibration (unreliability test, P = 0.412). Decision curve analysis demonstrated that the model was also clinically useful.
Conclusions: This study demonstrated that stone location, stone size, stone density, SSD, and hydronephrosis grade were significant predictors of stone-free failure after SWL guided by ultrasound in patients with ureteral stones. This may guide clinical practice.
World J Urol. 2023 Mar 13. doi: 10.1007/s00345-023-04358-3. Online ahead of print. PMID: 36912972
Comments 1
Comment
Stone fragments of ≥ 4 mm at 4 weeks or a second session within the first month were regarded as failure. A ~90% one session SWL success rate in 1698 patients of the development cohort and 712 of the validation cohort is very good. The inclusion criteria: stone size 6-20 mm, stone density failure group seems to suggest a short focal range. This is confirmed in another publication of the group on complication after SWL (1).
Of course, it would be ideal if patient selection could be based on a system for predicting success that reliably guarantees a very high success rate in one session. At the very moment, SWL could step to the forefront of stone therapy.
Why does this not happen? The general validity of the present and other scoring systems has to be evaluated individually in every setting where it is applied. That is probably one reason why none of the different scoring systems has been generally accepted as a routine for every user.
Another reason is the reimbursement problem: In 2016, an Italian doctor told me that the clinic's 20-year-old, defective lithotripter was not replaced with a new one. In the opinion of the administration, the investment was not worthwhile due to the low reimbursement of SWL compared to endourological procedures.
1 Na L, et al. Development and validation of a predictive model for major complications after extracorporeal shockwave lithotripsy in patients with ureteral stones: based on a large prospective cohort. Urolithiasis. 2023 Mar 2;51(1):42. doi: 10.1007/s00240-023-01417-7.PMID: 36862228
Free PMC article.
See also Malinaric R, et al. The Lifetime History of the First Italian Public Extra-Corporeal Shock Wave Lithotripsy (ESWL) Lithotripter as a Mirror of the Evolution of Endourology over the Last Decade.
Int J Environ Res Public Health. 2023 Feb 25;20(5):4127. doi: 10.3390/ijerph20054127
Free PMC article.
Peter Alken