Objective: To assess the effect of stone location and burden on the outcome of the extracorporeal shock wave lithotripsy (SWL) as a primary treatment of solitary renal stone.
Patients and methods: The study included 438 patients with a solitary renal stone who underwent SWL. All were evaluated by plain film of kidneys, ureters and bladder (KUB), ultrasonography, intravenous urography (IVU), or non-contrast enhanced CT. Patients were classified into four groups according to stone location (renal pelvis, lower, middle, and upper calyx) and three groups according to stone burden (≤ 1 cm2, 1.1-2 cm2, and > 2cm2).Treatment outcome was considered successful if no residual fragments (stone free) or clinically insignificant non obstructing residuals less than 4 mm were remained after 3 months of follow up.
Results: The mean age of the patients was 45.1± 12.5 years. The mean stone burden, number of sessions and shock waves for the whole study were 1.3± 0.49 cm2, 2.1±0.7 sessions and 5616.6±2017.4 shock waves, respectively. The stone free rate of the study was 65.1%. The stone free rates of the stones in the renal pelvis, lower, middle, and upper calyces were 72.4%, 56%, 55.6%, and 69%, respectively. The stone free rate of the stones ≤ 1 cm2, 1.1-2 cm2, and > 2cm2 was 50.2%, 39.6%, and 10.2%, respectively (P