title: Prognostic variables for shockwave lithotripsy (SWL) treatment success: no impact of body mass index (BMI) using a third generation lithotripter.
abstract: OBJECTIVE
  • To investigate the effect of different variables including body mass index (BMI) on therapy outcome in patients with upper urinary tract stones treated with a third generation lithotripter, as BMI has been reported to be an independent predictor for stone-free status after extracorporeal shockwave lithotripsy (SWL) performed with first or second generation lithotripters.
  
  
  METHODS
  • In all, 172 patients with kidney stones with a mean (range) size of 9.2 (3.0-32.0) mm were included in the study. • In all, 91 patients (52.9%) were treated with a ureteric stent in situ. • For SWL therapy a third generation, electromagnetic lithotripter (Siemens Lithoskop™) was used. Stone-free status was reached, when no more treatable stones were present (no stone or stone < 3 mm). • BMI, stone size and localization, age, gender, treatment parameters and ureteric stent in situ were evaluated for their prognostic relevance on therapy success.
  
  
  RESULTS
  • The mean (range) BMI of all patients was 27.8 (19.0-58.6) kg/m(2). • Patients were categorized into two groups: A) patients that were stone free after one treatment; B) patients with residual stones. The mean (sd) BMI was 27.4 (4.6) kg/m(2) and 28.4 (6.1) kg/m(2) for A and B, respectively. • Univariate and multivariate analysis for freedom of stones showed that only stone size (P < 0.01) and presence of a ureteric stent (P = 0.01) were independent prognostic variables. • BMI had no significant influence on therapy outcome (P = 0.51).
  
  
  CONCLUSIONS
  • Using a third generation lithotripter, BMI was not an independent predictor of stone-free rate after SWL therapy of kidney stones. • This effect might be attributed to a greater penetration depth of the shockwave energy. Stone size and a ureteric stent in situ were the only variables with prognostic significance.
authors.affiliation: Department for Urology, University of Heidelberg, Heidelberg, Germany. gencay.hatiboglu@med.uni-heidelberg.de
authors.forename: Gencay
authors.initials: G
authors.lastname: Hatiboglu
authors.forename: Valentin
authors.initials: V
authors.lastname: Popeneciu
authors.forename: Martin
authors.initials: M
authors.lastname: Kurosch
authors.forename: Johannes
authors.initials: J
authors.lastname: Huber
authors.forename: Sascha
authors.initials: S
authors.lastname: Pahernik
authors.forename: Jesco
authors.initials: J
authors.lastname: Pfitzenmaier
authors.forename: Axel
authors.initials: A
authors.lastname: Haferkamp
authors.forename: Markus
authors.initials: M
authors.lastname: Hohenfellner
mesh_terms: D000328:Adult; D015992:Body Mass Index; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000628:therapy*; D008096:Lithotripsy / Q000295:instrumentation; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012074:Remission Induction; D055815:Young Adult