title: Extracorporeal shock wave lithotripsy for lower calyceal stones: can clearance be predicted?
abstract: OBJECTIVE
  To determine the influence of pelvicalyceal angle, size of the lower calyx infundibulum and lowerpole calyceal anatomy in predicting the clearance of fragments after extracorporeal shock wave lithotripsy (ESWL) for lower calyceal stones.
  
  
  METHODS
  The study comprised a retrospective analysis of 133 patients, divided into 92 who were considered to be completely clear of fragments 6 months after ESWL and 41 who had residual stones. The pelvicalyceal angle, diameter of the lower calyx infundibulum and lower-pole calyceal pattern were determined from intravenous urograms.
  
  
  RESULTS
  There were residual stones in 64% of the patients with a pelvicalyceal angle < 90 degrees, in 12% of those with an angle > 90 degrees, in 70% of patients with an infundibular diameter < 4 mm, in 16% of those with a diameter > 4 mm, in 78% with a complex calyceal pattern and 12% with a simple calyceal pattern.
  
  
  CONCLUSIONS
  These three anatomical factors play a key role in predicting the clearance of stone and they should be assessed during intravenous urography to facilitate the planning of treatment for lower calyceal stones.
authors.affiliation: Muljibhai Patel Urological Hospital, Nadiad, Gujarat, India.
authors.forename: R B
authors.initials: RB
authors.lastname: Sabnis
authors.forename: K
authors.initials: K
authors.lastname: Naik
authors.forename: S H
authors.initials: SH
authors.lastname: Patel
authors.forename: M R
authors.initials: MR
authors.lastname: Desai
authors.forename: S D
authors.initials: SD
authors.lastname: Bapat
mesh_terms: D005544:Forecasting; D006801:Humans; D007669:Kidney Calculi / Q000473:pathology / Q000628:therapy*; D008096:Lithotripsy / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome