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A formal test of the hypothesis that idiopathic calcium oxalate stones grow on Randall’s plaque
Author(s) -
Miller Nicole L.,
Gillen Daniel L.,
Williams James C.,
Evan Andrew P.,
Bledsoe Sharon B.,
Coe Fredric L.,
Worcester Elaine M.,
Matlaga Brian R.,
Munch Larry C.,
Lingeman James E.
Publication year - 2009
Publication title -
bju international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.773
H-Index - 148
eISSN - 1464-410X
pISSN - 1464-4096
DOI - 10.1111/j.1464-410x.2008.08193.x
Subject(s) - medicine , percutaneous nephrolithotomy , calcium oxalate , ureteroscopy , percutaneous , dentistry , surgery , urinary system , anatomy , ureter
OBJECTIVE To confirm that more than half of all idiopathic calcium oxalate (CaOx) stones grow on interstitial plaque, as CaOx stones can grow attached to interstitial apatite plaque but whether this is the usual mechanism of stone formation is uncertain. PATIENTS AND METHODS In nine idiopathic CaOx stone formers (ICSF) undergoing percutaneous nephrolithotomy or ureteroscopy all accessible renal papillae were endoscopically imaged using a digital endoscope. All stones were removed intact, and recorded by the operating surgeon as being attached or unattached; for all attached stones the surgeon determined if the site of attachment was to plaque. This determination was further verified by reviewing the intraoperative video record, and only instances where plaque was reliably seen on video were used for analysis. Surgical observations were further validated by a combination of microcomputed tomographic analysis and papillary biopsy. The results were analysed statistically using fixed‐sample testing and group sequential sampling. RESULTS The nine patients had a total of 115 stones, primarily CaOx; 90 stones were attached. Of these, 81 were attached to plaque; surgeons could not visualize the site of attachment with sufficient clarity to judge in the other nine cases. Based on these data, the final point estimate for the number of stones attached to plaque was 0.754 (95% confidence interval 0.575–0.933; P = 0.013). CONCLUSIONS In ICSF most stones grow attached to papillae, on plaque, so growth on plaque is the main mechanism for stone formation in this very common group of patients.