title: Spectrum of stone composition: structural analysis of 1050 upper urinary tract calculi from northern India.
abstract: BACKGROUND
  The purpose of the present paper was to study the spectrum of stone composition of upper urinary tract calculi by X-ray diffraction crystallography technique, in patients managed at All India Institute of Medical Sciences.
  
  
  METHODS
  Between 30 April 1998 and 31 March 2003, a total of 1050 urinary calculi (900 renal, 150 ureteric) were analyzed. The stone fragments were collected after extracorporeal shock-wave lithotripsy, or retrieval by endoscopic (percutaneous nephrolithotomy, ureterorenoscopy), laparoscopic and various open surgical procedures. The structural analysis of the stones was done using X-ray diffraction crystallography.
  
  
  RESULTS
  Four types of primary and three secondary X-ray diffraction patterns were obtained. The primary patterns were as follows. Pattern A, well organized crystalline structure; pattern B, moderately organized crystalline structure; pattern C, poorly organized crystalline structure; pattern D, very poorly organized crystalline structure. The three secondary patterns mainly highlighted the mixed variety of stones. These patterns were further analyzed and compared with standard X-ray diffraction (powder) photographs. Of the 1050 stones analyzed, 977 (93.04%) were calcium oxalate stones, out of which 80% were calcium oxalate monohydrate (COM) and 20% were calcium oxalate dihydrate (COD). Fifteen were struvite (1.42%) and 19 were apatite (1.80%). Ten were uric acid stones (0.95%) and the remaining 29 (2.76%) were mixed stones (COM + COD and calcium oxalate + uric acid, calcium oxalate + calcium phosphate, and calcium phosphate + magnesium ammonium phosphate). A total of 89.98% of staghorn stones were made of oxalates (COM/+COD) and only 4.02% were struvite.
  
  
  CONCLUSIONS
  Urinary stone disease in the Indian population is different from that in Western countries, with a larger percentage of patients having calcium oxalate stones, predominantly COM. Also, the majority of staghorn stones (89.98%) were made of oxalates.
authors.affiliation: Department of Urology, All India Institute of Medical Science, New Delhi, India. ansarimsa@hotmail.com
authors.forename: Mohd S
authors.initials: MS
authors.lastname: Ansari
authors.forename: Narmada P
authors.initials: NP
authors.lastname: Gupta
authors.forename: Ashok K
authors.initials: AK
authors.lastname: Hemal
authors.forename: Premnath N
authors.initials: PN
authors.lastname: Dogra
authors.forename: Amlesh
authors.initials: A
authors.lastname: Seth
authors.forename: Monish
authors.initials: M
authors.lastname: Aron
authors.forename: Tej P
authors.initials: TP
authors.lastname: Singh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001031:Apatites / Q000032:analysis; D002129:Calcium Oxalate / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D018360:Crystallography, X-Ray; D005260:Female; D006801:Humans; D007194:India; D017616:Magnesium Compounds / Q000032:analysis; D008297:Male; D008875:Middle Aged; D010710:Phosphates / Q000032:analysis; D033362:Powder Diffraction; D000069877:Struvite; D014527:Uric Acid / Q000032:analysis; D014545:Urinary Calculi / Q000737:chemistry* / Q000648:ultrastructure*
chemical_list: D001031:Apatites; D017616:Magnesium Compounds; D010710:Phosphates; D002129:Calcium Oxalate; D014527:Uric Acid; D000069877:Struvite