Browsing by Subject "kidney calculi"

Now showing 1 - 4 of 4
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    Papillary Ductal Plugging Is a Mechanism for Early Stone Retention in Brushite Stone Disease
    (Elsevier, 2017) Williams, James C., Jr.; Borofsky, Michael S.; Bledsoe, Sharon B.; Evan, Andrew P.; Coe, Fredric L.; Worcester, Elaine M.; Lingeman, James E.; Department of Urology, School of Medicine
    Purpose Mechanisms of early stone retention in the kidney are under studied and poorly understood. To date attachment via Randall plaque is the only widely accepted theory in this regard, which is best described in idiopathic calcium oxalate stone formers. Brushite stone formers are known to have distinct papillary morphology relative to calcium oxalate stone formers. As such we sought to determine whether stone attachment mechanisms in such patients may be similarly unique. Materials and Methods Patients undergoing percutaneous and or ureteroscopic procedures for stone removal consented to endoscopic renal papillary examination and individual stone collection. Each removed stone was processed using micro computerized tomography to assess the 3-dimensional microstructure and the minerals contained, and search for common structural features indicative of novel mechanisms of early growth and attachment to renal tissue. Results A total of 25 intact brushite stones were removed from 8 patients and analyzed. Video confirmed attachment of 13 of the 25 stones with the remainder believed to have been accidently dislodged during the procedure. Microscopic examination by light and computerized tomography failed to show evidence of Randall plaque associated with any stone containing brushite. Conversely each brushite stone demonstrated microstructural evidence of having grown attached to a ductal plug formed of apatite. Conclusions Three-dimensional analysis of small brushite stones suggests overgrowth on ductal apatite plugs as a mechanism of early stone growth and retention. Such findings represent what is to our knowledge the initial supporting evidence for a novel mechanism of stone formation which has previously been hypothesized but never verified.
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    Preoperative Bladder Urine Culture as a Predictor of Intraoperative Stone Culture Results: Clinical Implications and Relationship to Stone Composition
    (Elsevier, 2016-09) Paonessa, Jessica E.; Gnessin, Ehud; Bhojani, Bhojani; Williams, James C.; Lingeman, James E.; Anatomy and Cell Biology, School of Medicine
    Purpose We examine the relationship between urine and stone cultures in a large cohort of patients undergoing percutaneous stone removal and compare the findings in infectious vs metabolic calculi. Materials and Methods A total of 776 patients treated with percutaneous nephrolithotomy who had preoperative urine cultures and intraoperative stone cultures were included in the study. Statistical analysis used chi-square or logistic fit analysis as appropriate. Results Preoperative urine culture was positive in 352 patients (45.4%) and stone cultures were positive in 300 patients (38.7%). There were 75 patients (9.7%) with negative preoperative cultures who had positive stone cultures, and in patients with both cultures positive the organisms differed in 103 (13.3%). Gram-positive organisms predominated in preoperative urine and stone cultures. Conclusions Preoperative urine cultures in patients undergoing percutaneous nephrolithotomy are unreliable as there is a discordance with intraoperative stone cultures in almost a quarter of cases. There has been a notable shift toward gram-positive organisms in this cohort of patients.
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    Preoperative Bladder Urine Culture as a Predictor of Intraoperative Stone Culture Results: Clinical Implications and Relationship to Stone Composition
    (Elsevier, 2016-09) Paonessa, Jessica E.; Gnessin, Ehud; Bhojani, Naeem; Williams, James C.; Lingeman, James E.; Anatomy and Cell Biology, School of Medicine
    Purpose We examine the relationship between urine and stone cultures in a large cohort of patients undergoing percutaneous stone removal and compare the findings in infectious vs metabolic calculi. Materials and Methods A total of 776 patients treated with percutaneous nephrolithotomy who had preoperative urine cultures and intraoperative stone cultures were included in the study. Statistical analysis used chi-square or logistic fit analysis as appropriate. Results Preoperative urine culture was positive in 352 patients (45.4%) and stone cultures were positive in 300 patients (38.7%). There were 75 patients (9.7%) with negative preoperative cultures who had positive stone cultures, and in patients with both cultures positive the organisms differed in 103 (13.3%). Gram-positive organisms predominated in preoperative urine and stone cultures. Conclusions Preoperative urine cultures in patients undergoing percutaneous nephrolithotomy are unreliable as there is a discordance with intraoperative stone cultures in almost a quarter of cases. There has been a notable shift toward gram-positive organisms in this cohort of patients.
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    Stone free outcomes of flexible ureteroscopy for renal calculi utilizing CT imaging
    (Elsevier, 2018) York, Nadya E.; Zheng, Mengmeng; Elmansy, Hazem M.; Rivera, Marcelino E.; Krambeck, Amy E.; Lingeman, James E.; Urology, School of Medicine
    Objectives To assess stone free rates following URS for renal calculi at our institution using low dose renal only CT (LDCT). Methods A retrospective review of patients undergoing flexible URS for renal stones only with subsequent CT scan within 3 months. Meticulous basketing of all stone fragments was performed whenever possible. A “true” zero fragment SFR was determined by reviewing the CT scan and radiologist's report. Patients with nephrocalcinosis (as determined by visual inspection of papilla at the time of URS) were assigned the “stone free” category. Results Flexible URS was performed in 288 renal units of 214 patients with renal calculi from 2013 to 2016. Median pre-operative stone size was 6.2mm with the average kidney containing 6.4 stones. An access sheath was used in 92% of cases. A total of 73% (209/288) renal units were completely stone free by CT assessment. Patients with residual fragments were as follows: 1mm in 2% (7/288), 2-4 mm in 16% (46/288), and >4 mm in 9% of kidneys (26/288). Conclusions The true stone free rate in patients undergoing flexible URS for renal calculi utilizing active basketing of fragments as determined by strict CT assessment was 73%. In patients with residual fragments, the majority are 2-4 mm in size making URS a treatment option for renal calculi with excellent stone free results.