title: Medical expulsive therapy as an adjunct to improve shockwave lithotripsy outcomes: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Modern shockwave lithotripsy (SWL) is associated with inferior results compared with the original Dornier HM3. To enhance SWL outcomes, improved patient selection based on radiographic features and modulation of shockwave delivery rate have been used. A growing body of evidence demonstrates the positive effect of medical expulsive therapy (MET) to improve spontaneous passage of urinary calculi. The purpose of this review is to tabulate the current available data that examine the addition of MET to SWL to enhance outcomes.
  
  
  METHODS
  MEDLINE was searched with a strategy developed in conjunction with a medical librarian. Trials were included if patients were randomized to receive either a medical expulsive agent or placebo or standard therapy after SWL. Study quality was assessed according to the Cochrane Renal Group criteria. The data were analyzed using RevMan meta-analysis software. Subgroup analysis was performed with respect to MET agent used, stone size, and duration of follow-up.
  
  
  RESULTS
  Four randomized trials were identified. MET agents varied, with two trials using tamsulosin, one using nifedipine, and a single trial using Phyllanthus niruri extract. Two trials included patients with renal calculi, one had patients with ureteral calculi, and the fourth included patients with both ureteral and renal calculi. The pool results of the four trials included 212 patients who received MET and 206 who received placebo. The absolute risk difference of a successful outcome after SWL with the addition of MET was significantly superior to control at 17% (95% confidence interval [CI] 9%-24%); means six patients need to be treated with MET to prevent a single unsuccessful SWL of six (95% CI 4-11). The effect of MET post-SWL was even more pronounced for stones larger than 10 mm with an absolute risk difference of 26% (95% CI, 9%-43%).
  
  
  CONCLUSIONS
  MET post-SWL results in a significant increase in successful treatment outcomes. Further powered, randomized studies are encouraged.
authors.affiliation: St. Michael's Hospital, Toronto, Ontario, Canada. ts9@ualberta.ca
authors.forename: Trevor D
authors.initials: TD
authors.lastname: Schuler
authors.forename: Rohan
authors.initials: R
authors.lastname: Shahani
authors.forename: R John D'A
authors.initials: RJ
authors.lastname: Honey
authors.forename: Kenneth T
authors.initials: KT
authors.lastname: Pace
mesh_terms: D006801:Humans; D008096:Lithotripsy; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome; D014545:Urinary Calculi / Q000628:therapy*