title: Extracorporeal shock wave lithotripsy produces a lower stone-free rate in patients with stones and renal cysts.
abstract: BACKGROUND
  Renal cysts have a space-occupying effect and therefore can distort the pelvicalyceal anatomy. This distortion often produces abnormalities in normal urinary drainage. In the same way, it may effect the ability of the kidneys to become stone free after extracorporeal shock wave lithotripsy (ESWL). The purpose of the current study is to evaluate the effect of renal cysts on the outcome of ESWL.
  
  
  METHODS
  We studied 15 patients who had renal stones and coexistent renal cysts. Four patients had polycystic disease, five patients had multiple cysts and six patients has solitary ones. All cysts produced a distortion to the calyceal system of the kidneys, a fact confirmed by intravenous urography (IVU) and computed tomography (CT). All patients underwent ESWL and their stone-free status was evaluated 1 month later by ultrasound and plain kidney ureter bladder (KUB) X-ray.
  
  
  RESULTS
  We had a total 60% (9/15) stone-free patients in our study group and a stone fragmentation rate of 100%. Patients with more cysts had lower stone-free rates. Patients with polycystic kidneys had a 25% (1/4) stone-free rate, while patients with multiple cysts and solitary cysts had, 60% (3/5) and 83.3% (5/6), respectively. These results are lower than the rates reported in patients without renal cysts.
  
  
  CONCLUSIONS
  We believe that renal cysts may interfere with the passage of stone fragments, due to the impediment of drainage and urinary stasis from the stretching and distortion of the calyceal system by the renal cysts.
authors.affiliation: University of Athens, Second Department of Urology, Sismanoglion Hospital, Greece. nikistra@hol.gr
authors.forename: Charalambos
authors.initials: C
authors.lastname: Deliveliotis
authors.forename: Vasilios
authors.initials: V
authors.lastname: Argiropoulos
authors.forename: John
authors.initials: J
authors.lastname: Varkarakis
authors.forename: Stefanos
authors.initials: S
authors.lastname: Albanis
authors.forename: Andreas
authors.initials: A
authors.lastname: Skolarikos
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000150:complications* / Q000628:therapy*; D052177:Kidney Diseases, Cystic / Q000150:complications*; D008096:Lithotripsy; D008297:Male; D008875:Middle Aged