Faddan AA. et al., 2023: Predictors of stone-free rate after a single-session extracorporeal shockwave lithotripsy for a single kidney stone measuring 10 to 20 mm: A private center experience.
Faddan AA, Najieb O, Gadelkareem RA.
Assiut Urology and Nephrology Hospital, Faculty of Medicine, Assiut University, Assiut, Egypt.
Health Insurance Hospital, Ministry of Health, Mallawy, Egypt.
Abstract
Background: Despite the continuous update of guidelines for the management of kidney stones, the ability to predict a successful response to extracorporeal shockwave lithotripsy (SWL) remains a topic of research. This is due to the need to refine the decision making in the context of technological advancements and current pandemics. This study aimed to determine the predictors of stone-free rate (SFR) after single-session SWL in adult patients with a single kidney stone 10 to 20 mm in diameter.
Materials and methods: A retrospective review of the records of patients with a single kidney stone 10 to 20 mm in diameter was performed at a private SWL center from December 2019 to February 2021. Univariate and multivariate analyses were performed for stone- and patient-related factors, using the Student t and Mann-Whitney U tests for the quantitative variables and the Fisher exact and Pearson correlation tests for the qualitative variables.
Results: A total of 138 patients were eligible for this study, including 92 men and 46 women. The mean age was 38.6 ± 12.4 years, and the mean body mass index (BMI) was 25.9 ± 3.4 kg/m2. Four weeks after SWL, 120 patients (87%) were free of stones, and 18 (13%) needed further treatment. Univariate analyses showed that SFR was negatively correlated with increased BMI (p = 0.0001), maximum stone length (p = 0.0001), transverse diameter of the stone (p = 0.0001), number of shocks per session (p = 0.052), and Hounsfield unit (HU) (p = 0.0001). Multivariate analysis revealed that HU (p = 0.009), maximum stone length (p = 0.01), BMI (p = 0.000), and presence of double-J stent (p = 0.034) were independent risk factors for failure of single-session SWL in the treatment of kidney stones 10 to 20 mm in diameter. The estimated average cost per case was USD 450.5.
Conclusions: Increased HU, maximum stone length, BMI, and presence of double-J stents were independent risk factors for low SFR after single-session SWL for a kidney stone 10 to 20 mm in diameter. The cost of SWL remains an advantage in the private sector.
Curr Urol. 2023 Mar;17(1):30-35. doi: 10.1097/CU9.0000000000000152. Epub 2022 Sep 16.
PMID: 37692133 FREE PMC ARTICLE
Comments 1
The authors report their experience with SWL in a private center. Only patients with stones in the kidney and measuring 10-20 mm were included.
Obviously the SWL-technique was good, and 120 patients (87%) were stone-free after one session. The definition of stone-free included fragments up to 4 mm!
The achievement was as follows:
1 session 2 sessions 3 sessions 4 sessions
120 9 3 2
Four patients were treated with PNL!
Like other studies of this kind they found that BMI, large stone size and hard stones (high HU) were less successfully treated. Presence of an internal stent also had a negative effect of the treatment outcome.
The results are like those encountered in our own unit in Stockholm with the reservation that we also included both smaller (20 mm) stones.
Interestingly and of great health economic importance is the conclusion that the average cost of one SWL treatment was 421 USD.
Hans-Göran Tiselius