title: The effect of renal cortical thickness on the treatment outcomes of kidney stones treated with shockwave lithotripsy.
abstract: OBJECTIVE
  Because the shock wave passes through various body tissues before reaching the stone, stone composition may affect the treatment efficacy of shock wave lithotripsy (SWL). We investigated the effect of various tissue components along the shock wave path on the success of SWL.
  
  
  METHODS
  From October 2008 to August 2010, a total of 206 patients with kidney stones sized 5 to 20 mm were prospectively recruited for a study of the factors that affect the outcome of treatment with a Sonolith Vision lithotripter. Successful SWL was defined as either stone-free status or residual fragments <4 mm at 12 weeks. Logistic regression analysis was performed to assess the factors that predicted treatment outcomes. Potential predictors included the patient's age, shock wave delivery rate, stone volume (SV), mean stone density (MSD), skin-to-stone distance (SSD), and the mean thickness of the three main components along the shock wave path: renal cortical thickness (KT), muscle thickness (MT), and soft-tissue thickness (ST).
  
  
  RESULTS
  The mean age of the patients was 53.8 years (range, 25-82 years). The overall treatment success rate after one session of SWL was 43.2%. The mean KT, MT, and ST were 26.9, 16.6, and 40.8 mm, respectively. The logistic regression results showed that a slower shock wave delivery rate, smaller SV, a lower MSD, and a thicker KT were found to be significant predictors for successful SWL. SSD, MT, and ST were not predictors of successful treatment.
  
  
  CONCLUSIONS
  Among the main tissue components along the shock wave path, a thicker KT was a favorable factor for successful SWL after adjustment for SV, MSD, and the shock wave delivery rate.
authors.affiliation: The S.H. Ho Urology Centre, Department of Surgery, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Chi-Fai
authors.initials: CF
authors.lastname: Ng
authors.affiliation: The S.H. Ho Urology Centre, Department of Surgery, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Luke
authors.affiliation: The S.H. Ho Urology Centre, Department of Surgery, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Peter K F
authors.initials: PK
authors.lastname: Chiu
authors.affiliation: The S.H. Ho Urology Centre, Department of Surgery, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Jeremy Y C
authors.initials: JY
authors.lastname: Teoh
authors.affiliation: Department of Imaging and Intervention Radiology, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Ka-Tak
authors.initials: KT
authors.lastname: Wong
authors.affiliation: The S.H. Ho Urology Centre, Department of Surgery, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Simon S M
authors.initials: SS
authors.lastname: Hou
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000628:therapy*; D007672:Kidney Cortex / Q000000981:diagnostic imaging*; D008096:Lithotripsy; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
keywords: Lithotripsy; Treatment outcome; Urolithiasis