Pelvicaliceal anatomical variation between stone bearing and normal contralateral kidneys - Does it have an impact on stone formation in pediatric patients with a solitary lower caliceal stone?

Purpose: We aimed to investigate the probable effect of pelvicaliceal anatomical differences between stone bearing and normal contralateral kidneys on the etiology of stone formation in children with a solitary lower pole caliceal stone. Materials and Methods: We reviewed the clinical records of 25 pediatric patients who underwent SWL for a solitary lower caliceal stone and 15 healthy pediatric patients who served as controls. Lower pole IPA, IL and IW, together with other caliceal variables obtained from the pelvicaliceal anatomy of the stone bearing and contralateral normal kidneys of patients with urolithiasis, and both kidneys of the control group were measured based on excretory urography. Also, total pelvicaliceal volume for both kidneys was calculated. Results: Mean LIPAs of stone bearing kidneys compared to the normal contralateral. kidneys was more acute, equal and wider in 52%, 16% and 32% of the patients, respectively. Mean pelvicaliceal volumes of the stone forming and normal kidneys were 1,553.8 mm(3) (range 242 to 7,107) and 581.0 mm(3) (90 to 2,662), respectively, and there was statistical significance only in pelvicaliceal volumes between the stone bearing and contralateral normal kidneys (p < 0.001). Conclusions: Our results reveal that IPA, IL and IW of calices do not have an effect on stone formation in pediatric patients. However, large pelvicaliceal volume seems to be a significant risk factor for stone formation in the lower calix, probably because it creates abnormal urodynamic and morphological features, especially when accompanied by other metabolic abnormalities.