Abstract

Introduction: The success rate of ESWL in the treatment of lower pole kidney stones is limited. Considerable controversy exists concerning the management of lower pole kidney stones. A possible factor for lower stone clearance rate is lower pole collection system anatomy. In this study, we evaluated the impact of infundibulopelvic anatomy and angle on stone clearance of lower pole kidney stones after shock wave lithotripsy.

Materials and Methods: Between January 2001 and January 2003, a total of 93 patients with lower pole kidney stones treated with ESWL. Stone burden was measured as the longest linear diameters observed on intravenous urography (IVU). Antibiotic prophylaxis was given to all patients before ESWL and parenteral analgesics were given during ESWL. Before ESWL, infundibulopelvic angle, infundibuler diameter and wideness as well as stone diameter were recorded. The stones were divided into 3 groups according to stone diameter: Stone diameter was <10 mm in 42 patients (45.2%), 10-20 mm in 33 patients (35.5%) and >20 mm in 18 (19.3%). The stones after ESWL were radiologically controlled and stone-free status was confirmed after 4 weeks. Stone-free rates according to infundibulopelvic angle (IPA), infundibuler diameter and wideness and stone diameter were analyzed.

Results: Mean age was 43.8 (range between 15 and 79) years. There were 53 men (57%) and 40 women (43%). Stone clearance rates according to infundibulopelvic angle for IPA >45° and ≤45° were 78.4% and 62% and for IPA ≤90° and >90° were 65.3% and 94.4%, respectively. When stratified by infundibuler diameter, the results of our study showed stone free rates of 61.9% and 78.4% for diameters >3 cm and ≤3 cm. The clearance rates according to infundibuler wideness were 78.9% and 65% for >5 mm and ≤5 mm, respectively. The stones <10 mm had a higher stone clearance rate (83.3%). The success rates for stones between 10-20 mm and >20 mm were 66.6% and 50%, respectively. The success rate was higher when stone diameter decreased and infundibulopelvic angle increased. When the ratio of infundibuler diameter to wideness was low, stone clearance rate was high.

Conclusions: ESWL is the preferred approach for most patients with lower pole stones smaller than 1 cm. The infindibulopelvic angle, infundibuler diameter and wideness as well as stone diameter should be regarded together in order to choose a treatment approach for lower pole kidney stones.