title: Retrograde Intrarenal Surgery Versus Shock Wave Lithotripsy for Renal Stones Smaller Than 2 cm: A Randomized Clinical Trial.
abstract: OBJECTIVE
  To compare outcomes of retrograde intrarenal surgery (RIRS) with extracorporeal shock wave lithotripsy (SWL) for stones &le; 2 cm.
  
  
  METHODS
  Patients who were diagnosed with kidney stones of &le; 2 cm underwent RIRS or SWL in a parallel group randomized clinical trial with balanced randomization [1:1] from 2011 to 2014. The primary outcome of interest was stone free rate after a single session intervention. Patients were evaluated by ultrasonography and KUB at 1 and 3 months after the intervention for the presence of residual stone by a radiologist who was blinded to the study.
  
  
  RESULTS
  The stone free rate one month after a single session intervention in the RIRS group was higher than the SWL group (90% versus 75%, P = .03). The success rates after two sessions of RIRS versus SWL were 96.7% versus 88.3% respectively. (P = .08) Patients in the RIRS group had significantly lower postoperative visual analogue pain score compared to the SWL group (5.2 &plusmn; 2.8 versus 3.1 &plusmn; 2.7, P &lt; .001). Steinstrasse formation and renal hematoma were observed in 4 and one patient in the SWL group versus no patient in the RIRS group. Postoperative hospital stay was significantly shorter in the SWL group (6.7 &plusmn; 1.3 versus18.9 &plusmn; 4.3 hours, P &lt; .001).
  
  
  CONCLUSIONS
  The RIRS procedure is a safe treatment option for renal stones of &le;2cm with less pain and higher success rate at first session compared to SWL.&nbsp.
authors.affiliation: Laser Application in Medical Sciences Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran. drbabakjavanmard@gmail.com.
authors.forename: Babak
authors.initials: B
authors.lastname: Javanmard
authors.affiliation: Hasheminejad Kidney Center, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Amir Hossein
authors.initials: AH
authors.lastname: Kashi
authors.affiliation: Laser Application in Medical Sciences Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Mohsen
authors.initials: MM
authors.lastname: Mazloomfard
authors.affiliation: Urology and Nephrology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Anahita
authors.initials: A
authors.lastname: Ansari Jafari
authors.affiliation: Department of Surgery, School of Medicine, Washington University in St. Louis, Saint Louis, Missouri, United States.
authors.forename: Saeed
authors.initials: S
authors.lastname: Arefanian
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000473:pathology / Q000601:surgery / Q000628:therapy*; D008096:Lithotripsy / Q000009:adverse effects; D008297:Male; D011446:Prospective Studies; D016037:Single-Blind Method