title: Variation in clinical outcome following shock wave lithotripsy.
abstract: OBJECTIVE
  We measure and compare operator specific success rates of extracorporeal shock wave lithotripsy (ESWL) performed by 12 urologists in 1 unit to determine interoperator variation.
  
  
  METHODS
  From January 1, 1994 to September 1, 1997 a total of 5,769 renal and ureteral stones received 9,607 ESWL treatments by 15 urologists with a Dornier MFL 5000 lithotriptor. The 3-month followup data are available for 4,409 stones. Outcome measures consisted of patient demographics, stone characteristics, technical details of lithotripsy, and stone-free and success rates by treating urologists.
  
  
  RESULTS
  Treatment results were analyzed for 12 urologists (surgeons A to L) who treated more than 100 stones each, totaling 4,244 with followup information available. Mean stone-free and success rates were 50.6% and 72.3%, respectively. Surgeon A had significantly higher stone-free and success rates of 56.2% and 76.7%, respectively (p<0.05), with treatment results from 877 stones, which was a significantly higher number than others (p<0.05). Significant differences existed in mean number of shocks delivered among urologists (p = 0.0001), with surgeons A and J delivering the highest mean numbers (2,317 and 2,801, respectively). There was no difference in treatment duration (p = 0.75) but variation existed among urologists in terms of mean maximum treatment voltage (p = 0.0001). Mean fluoroscopy time at 4.1 minutes was higher for surgeon A than others (p<0.05). Mean complication rate following ESWL was 4.9% with no difference among urologists (p = 0.175). Re-treatment was required in 21.7% of cases and surgeon A had the lowest rate (15.9%, p<0.05).
  
  
  CONCLUSIONS
  We demonstrated clinically and statistically significant intra-institutional differences in success rates following ESWL. The best results were obtained by the urologist who treated the greatest number of patients, used a high number of shocks and had the longest fluoroscopy time. Accurate targeting is crucial when using a lithotriptor, such as the Dornier MFL 5000, with a narrow focal zone of 6.5 mm. in diameter. Other centers should be encouraged to develop similar programs of outcome analysis in an attempt to improve performance.
authors.affiliation: Urolithiasis Program, Division of Urology, The University of Toronto, Ontario, Canada.
authors.forename: N F
authors.initials: NF
authors.lastname: Logarakis
authors.forename: M A
authors.initials: MA
authors.lastname: Jewett
authors.forename: J
authors.initials: J
authors.lastname: Luymes
authors.forename: R J
authors.initials: RJ
authors.lastname: Honey
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007669:Kidney Calculi / Q000628:therapy*; D008096:Lithotripsy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016896:Treatment Outcome; D014514:Ureteral Calculi / Q000628:therapy*