Is stone clearance after shockwave lithotripsy in patients with solitary upper-caliceal stone influenced by anatomic differences in the pelvicaliceal system?

PURPOSE

We investigated the effect of pelvicaliceal differences on stone clearance after extracorporeal shockwave lithotripsy (SWL) in patients with solitary upper-caliceal stones.

PATIENTS AND METHODS

The clinical records of patients with solitary upper-caliceal stones who underwent SWL between 1996 and 2004 were reviewed. After excluding patients with hydronephrosis, significant anatomic abnormalities, non-calcium stones, metabolic abnormalities, recurrent stone disease, multiple stones, and previous renal surgery, 42 patients with a mean stone size of 153.47 mm2 (range 20-896 mm2) were enrolled in this study. They were divided into three groups according to stone burden (group 1 < or =100 mm2, group 2,101 mm2-200 mm2, and group 3 >200 mm2). Upper-pole infundibulopelvic angle (IPA), infundibular length (IL), and infundibular width (IW) were measured from intravenous urograms.

RESULTS

Of the total, 29 patients (69%) were stone free after SWL treatment. The differences in the upperpole IPA, IL, and IW of stone-free patients and patients with residual stones were not statistically significant (P = 0.85, P = 0.89, and P = 0.37, respectively). Again, there were no statistically significant differences in terms of upper IPA, IW, and IL in comparing the three groups divided by initial stone size.

CONCLUSION

Upper-caliceal anatomy does not exert a significant impact on stone clearance after SWL for isolated upper-caliceal stones. To best of our knowledge, this is the first study to investigate the effects of pelvicaliceal anatomy on SWL treatment for upper-caliceal stones, so there is a need for further investigations to confirm our findings.