Endoscopic evidence of calculus attachment to Randall's plaque.
OBJECTIVE
It has been proposed that calcium oxalate calculi begin as small stones attached to the renal papillae at sites of Randall's plaque. However, no study has investigated the prevalence of attached stones in calcium oxalate stone formers or the relationship between stone attachment site and Randall's plaque. In this study we used endoscopic examination of renal papillae in stone formers undergoing percutaneous nephrolithotomy to investigate both issues.


METHODS
Idiopathic calcium oxalate stone formers undergoing PNL for stone removal were enrolled in this study. Multiple papillae were examined and images were recorded by digital video. The presence or absence of papillary plaque and attached stones was noted, as was the site of stone attachment.


RESULTS
In 23 patients, 24 kidneys and 172 renal papillae were examined. All kidneys were found to have papillary plaque and 11 of the patients had attached stones. Most papillae (91%) contained plaque.


CONCLUSIONS
The prevalence of attached stones in calcium oxalate stone formers (48%) is greater than that previously reported for the general population. Attachment appears to be on Randall's plaque. The high prevalence of attached stones and the appearance of the attachment site are consistent with a mechanism of calcium oxalate stone formation in which stones begin as plaque overgrowth.
Matlaga
Brian R
BR
Methodist Hospital Institute for Kidney Stone Disease, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
Williams
James C
JC
Kim
Samuel C
SC
Kuo
Ramsay L
RL
Evan
Andrew P
AP
Bledsoe
Sharon B
SB
Coe
Fredric L
FL
Worcester
Elaine M
EM
Munch
Larry C
LC
Lingeman
James E
JE
D002129:Calcium Oxalate / Q000032:analysis; D004724:Endoscopy; D006801:Humans; D007669:Kidney Calculi / Q000737:chemistry / Q000473:pathology*; D007679:Kidney Medulla
D002129:Calcium Oxalate