Impact of Extracorporeal Shock Wave Lithotripsy (ESWL) on Kidney Length and Corticomedullary Differentiation in Patients With Renal Stones: A Case-Control Study

Background The effect of extracorporeal shock wave lithotripsy (ESWL) on kidney morphology was evaluated sonographically in patients with renal stones. This study aimed to investigate the effects of ESWL on the kidneys after consecutive sessions. Methods This case-control study included adult participants from December 2018 to August 2022 in three major centers of ESWL treatment. Data were collected from 392 patients (336 treated with ESWL and 56 in the control group). Data were analyzed using SPSS Statistics (IBM Corp., Armonk, USA). Both binary logistic regression and generalized linear regression were applied to determine the factors that predicted the effect of ESWL on kidney length (KL) and cortico-medullary differentiation (CMD). Results The overall effect of ESWL treatment on patients with renal stones was observed in 19.9% disturbed CMD, and 11.6% decreased parenchymal thickness. KL was significantly decreased in patients exposed to ESWL compared to controls (9.103 vs.10.291 cm, p-value < .001). KL decreased significantly as the number of ESWL sessions increased (r = -.209, p-value < .001). After adjustment, the frequencies of ESWL and hydronephrosis were significantly associated with CMD distortion. Patients who were exposed to more than one ESWL session had 2.64 increased odds of distorted CMD as compared to controls (AOR=2.64, 95% CI = 1.040-6.683), and those with hydronephrosis had 1.70 increased odds of distorted CMD as compared to controls (AOR=1.70, 95% CI = 1.188-2.434). Conclusion ESWL significantly affected the renal length and CMD in patients with renal stones. The frequency of ESWL sessions significantly decreased KL and disturbed CMD in patients with renal stones. The outcome was not affected by the number of stones.