Background: Renal stones represent a common urological pathology where standard treatment advised is ESWL in current practice. However, NCCT based determination of stone fragility may help to predict the outcome of ESWL treatment, hence optimizing its clinical use. Therefore, this study evaluated the role of NCCT determined urinary stone fragility in predicting the outcome of ESWL treatment in local clinical settings.
Patients and methods: One hundred patients with single renal calculus of 0.6-2 cm in size were included. NCCT based determination of stone fragility in HU units was done for all patients. Patients were then subjected to ESWL, with a maximum of 3000 shock waves given per ESWL session. Plain film and/or ultrasonography was used to monitor ESWL treatment progress with a final NCCT evaluation at 12 weeks to determine the clearance of the calculi for each patient. Association of NCCT based stone fragility and outcome of ESWL was statistically analyzed using Fisher exact test.
Results: The mean age of the patients was 37.7 ± 10.9 years with 54% being male. Decreasing stone fragility on NCCT (high = <500HU, moderate = 500-1000HU, and high = 1000HU) required more number and intensity of ESWL sessions (1-2 visits and 3000-6000 shock waves for high stone fragility group, 3-5 visits and 7000-18000 shock waves for the moderate group, and 6 visits and >18000 shock waves for low fragility group, respectively) necessary for clearance of urinary stones (p<0.001). In 98% of patients, the clearance of urinary stones was excellent.
Conclusion: Renal stone patients with NCCT determined high and moderate stone fragility show an optimal response after ESWL treatment, whereas, for low fragility renal stones attenuative treatment like percutaneous nephrolithotomy and/or ureteroscopy should be considered instead of ESWL. This approach can enable patient stratification before ESWL therapy ensuring better clinical management of the renal stone disease.
