title: Predictors of clinical significance of residual fragments after extracorporeal shockwave lithotripsy for renal stones.
abstract: OBJECTIVE
  To determine the predictors of the clinical outcome of residual fragments after extracorporeal shockwave lithotripsy (SWL).
  
  
  METHODS
  During the last 10 years, residual fragments < or =5 mm were present in 99 male and 55 female patients (mean age 43.1 years) for >3 months after SWL for renal stones. Follow-up with history, urine examination, and non-contrast CT scanning was carried out every 6 months or when symptoms developed. Clinically insignificant residual fragments were diagnosed in patients who became stone free or had asymptomatic fragments of the same size during follow-up. A clinically significant outcome was considered to have occurred in patients requiring secondary intervention for regrowth of the fragments or medical treatment for frequent symptomatic episodes. Univariate (Kaplan-Meier) and multivariate (Cox-regression) analyses were performed to determine significant predictors of the outcome. The mean follow-up was 31 months (range 6-80 months).
  
  
  RESULTS
  Stone-free status, regrowth of fragments, and persistence of fragments of the same size were present in 21 (13.6%), 52 (33.8%), and 81 (52.6%) patients, respectively. A clinically significant outcome was documented in 75 patients (48.7%) as percutaneous nephrolithotomy was needed in 2, repeat SWL in 50, and medical treatment for symptomatic episodes in 23 patients. Significant independent predictors of a clinically significant outcome were fragment size > or =4 mm and history of recurrent stone disease (P < 0.001).
  
  
  CONCLUSIONS
  The term "clinically insignificant residual fragments" is not appropriate for all patients with post-SWL fragments, as 48.7% of patients had fragments that became clinically significant. Fragments of 4 to 5 mm and recurrent stone disease predicted clinical significance.
authors.affiliation: Urology and Nephrology Center, Mansoura University, Mansoura, Egypt. ar_el_nahas@yahoo.com
authors.forename: Ahmed R
authors.initials: AR
authors.lastname: El-Nahas
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: El-Assmy
authors.forename: Khaled
authors.initials: K
authors.lastname: Madbouly
authors.forename: Khaled Z
authors.initials: KZ
authors.lastname: Sheir
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007669:Kidney Calculi / Q000628:therapy*; D008096:Lithotripsy; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome