Impact of anatomical pielocaliceal topography in the treatment of renal lower calyces stones with extracorporeal shock wave lithotripsy.

There is wide consensus that the lowest success rate of extracorporeal shock wave lithotripsy (ESWL) is in the complete clearance of renal stones located in the lower calyces. We assess the effectiveness of extracorporeal shock wave lithotripsy monotherapy for lower pole renal calculi to determine the relationship between the spatial anatomy of lower pole and the outcome of ESWL. METHODS: We evaluated 107 patients who were treated for solitary lower pole renal stones less than 20 mm in diameter with ESWL. The spatial anatomy of the lower pole, as defined by the lower infundibulopelvic angle, infundibular length and infundibular width, was measured by preoperative intravenous pyelography, while the stone location and size were determined by using abdominal plain X-ray. All patients were followed up at 1 and 3 months with abdominal plain X-ray and ultrasonography. RESULTS: Only 62 patients (58%) became stone free, while 45 (42%) retained residual fragments. A small lower infundibulopelvic angle, a long infundibular length and a tight infundibular width are unfavorable for stone clearance after ESWL. CONCLUSIONS: ESWL is the treatment of choice for most renal and ureteral stones. However, stone clearance from the lower pole following ESWL is poor and significantly affected by the inferior pole collecting system anatomy. Therefore, we believe it is important to evaluate these anatomical factors when deciding on the best treatment for lower pole renal calculi.