Objective: To assess the effect of the gravity-related
radiographic features on the success rate of extracorporeal shock wave
lithotripsy (SWL) in renal stones.
Materials and methods: A total of 79 patients (mean
age 47.34±12.9 year) who underwent SWL due to renal pelvis stones (mean
area 162.58±130.31 mm²) between 2005 and 2008 were enrolled. Three
angles on the pretreatment excretory urography were measured; the inner
angle between the axis of the lower pole infundibular and ureteropelvic
axis (angle 1), lower pole infundibular axis and main axis of
pelvis-ureteropelvic junction point (angle 2), and lower pole
infundibular axis and perpendicular line (angle 3). Age, number of
session, stone burden, numbers of shock waves, and presence of
hydronephrosis were defined for all patients. The significant predictors
of stone-free rate after the application of SWL was defined.
Results: The success rate was 53.2%. All angles,
number of sessions, stones burden, and number of shock waves were
significant predictors of stone free rate. However, age, sex and the
presence of hydronephrosis did not show similar effects.
Conclusions: Gravity-related factors have significant
role on the stone-free rate in patients treated with SWL for renal
pelvis stones. These radiographic parameters may be used to determine
the patients who will benefit from SWL.