title: Crystallite size--is it a new predictor for renal stone burden?
abstract: OBJECTIVE
  To evaluate the importance of stone composition and crystallite size in the formation of ultimate stone burden. Crystallite is the smallest building block, which is unique in size and architecture for each type of stone component. Currently, the knowledge about the clinical importance of crystallite size is very limited.
  
  
  METHODS
  The results of quantitative X-ray diffraction phase analysis performed on 286 kidney stones extracted during endourological surgery or expelled spontaneously were retrospectively analyzed. Stone composition and crystallite size were determined and were compared to the burden occupying the pelvicalyceal system.
  
  
  RESULTS
  A total of 286 renal stones were analyzed. Stones were low burden and high burden in 242 and 44 of cases, respectively. We observed statistically significant association of phosphates and urates with high-burden stones in contrast to oxalates, which formed mainly low-burden stones. Crystallite sizes were available for 179 stones. Large-sized crystallites of calcium oxalate monohydrate and hydroxyl apatite formed low-burden stones, whereas small-sized crystallites formed staghorn stones. Struvite and urates had a uniform average size of crystallites.
  
  
  CONCLUSIONS
  Oxalate stones have statistically significant association with smaller stones, whereas high-burden calculi are significantly associated with urates and phosphates, especially the struvite type. The smaller the crystallite size is to start with, the larger will be the ultimate stone burden. This rule is followed by calcium oxalate monohydrate and Apatite minerals.
authors.affiliation: Department of Urology, Hadassah Hebrew University Hospital, Jerusalem, Israel. moti_duv@yahoo.com
authors.forename: Nandakishore K
authors.initials: NK
authors.lastname: Shapur
authors.forename: Vladimir
authors.initials: V
authors.lastname: Uvarov
authors.forename: Inna
authors.initials: I
authors.lastname: Popov
authors.forename: Ran
authors.initials: R
authors.lastname: Katz
authors.forename: Ofer N
authors.initials: ON
authors.lastname: Gofrit
authors.forename: Ezekiel H
authors.initials: EH
authors.lastname: Landau
authors.forename: Dov
authors.initials: D
authors.lastname: Pode
authors.forename: Mordechai
authors.initials: M
authors.lastname: Duvdevani
mesh_terms: D001031:Apatites / Q000032:analysis; D002129:Calcium Oxalate / Q000032:analysis; D018360:Crystallography, X-Ray; D006801:Humans; D007669:Kidney Calculi / Q000737:chemistry / Q000000981:diagnostic imaging*; D010710:Phosphates / Q000032:analysis; D011859:Radiography; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D001031:Apatites; D010710:Phosphates; D002129:Calcium Oxalate