Spectrum of stone composition: structural analysis of 1050 upper urinary tract calculi from northern India

Infrared and Raman studies on renal stones: the use of second derivative infrared spectra

Urolithiasis is a very frequent illness found in Argentina; however, stone analysis is not routinely performed. In this work, 86 renal calculi (from cities of Luján and San Antonio de Areco, State of Buenos Aires, Argentina) have been analyzed by infrared and Raman spectroscopies, and the results correlated with the main possible pathological conditions. Calcium oxalate monohydrate (whewellite) and mixtures of calcium oxalate monohydrate and carbonate apatite were the most frequent compounds found in our samples. In order to improve the identification of different phases present in calculi [particularly whewellite and weddellite (calcium oxalate dihydrate)], the second derivative spectra were used. The FTIR spectroscopy together with the second derivative analysis provides the urologist with a good method for calculi component determinations.

Caracterização de cálculos renais por análise térmica

Dez amostras de cálculos renais foram estudadas por Análise Elementar de CHN (EA), Espectroscopia de Absorção no Infravermelho (IV) e Difração de raios X pelo método de Pó (XRD). O comportamento térmico das amostras foi estudado por Termogravimetria/Termogravimetria Derivada (TG/DTG) e por Calorimetria Exploratória Diferencial (DSC). Os resultados de EA, Espectroscopia de Absorção IV e XRD mostraram a presença de estruvita [NH4Mg(PO4).6H2O], apatita, oxalato de cálcio monohidratado e oxalato de cálcio dihidratado. As curvas TG e DSC permitiram classificar as amostras em dois grupos diferentes: Grupo I mostrando comportamento térmico típico de estruvita e Grupo II apresentando um perfil termoanalítico característico de mistura de oxalatos.

Stone composition: where do we stand?

Kidney stones are a common disorder of the urinary tract. Nephrolithiasis is a morbid and expensive disease. The prevalence and incidence are estimated at 5-10% and 100-300/100,000/year, respectively. Relapses occur in 50-70% of all cases. For these reasons, prevention of stone formation is of great importance. Knowing the composition of the calculus is thus fundamental for a more complete evaluation of the metabolic study. The nature of the calculus in fact helps the physician to find a convenient metaphylaxis consisting of both sanitary and therapeutic measures. Study of the composition of urinary stones remains one of the most interesting aspects of the lithiasic pathology today. Presently crystallographic examination constitutes one of the most precise and less expensive methodologies to identify the nature of the concretion. This method also allows the urologist to catalogue the typology of the lithiasis during endoscopy.

Ethnic differences in relative risk of idiopathic calcium nephrolithiasis in North America

PURPOSE

Data on susceptibility to kidney stone disease are sparse in individuals of nonEuropean ancestry residing in North America. We determined the relative risk of calcium nephrolithiasis among people of different ethnic backgrounds living in the same geographic region.

MATERIALS AND METHODS

Using a cross-sectional design 1,128 consecutive patients with idiopathic calcium nephrolithiasis 18 to 50 years old were recruited from a population based Kidney Stone Center in Toronto. Age and gender adjusted odds ratios and 95% confidence intervals were calculated by logistic regression using the 2001 Canada Census population data.

RESULTS

Compared to Europeans the relative risk of calcium nephrolithiasis was significantly higher in individuals of Arabic (OR 3.8, 2.7-5.2), West Indian (OR 2.5, 1.8-3.4), West Asian (OR 2.4, 1.7-3.4) and Latin American (OR 1.7, 1.2-2.4) origin, and significantly lower in those of East Asian (OR 0.4, 0.3-0.5) and African (OR 0.7, 0.5-0.9) background. Several ethnic groups had kidney stone risk factors that were significantly different from those of the European group including higher urinary uric acid, urea excretion and estimated protein intake, and lower urinary citrate, potassium, magnesium and phosphate excretion. However, none was consistent with the variation in relative risk of stone disease overall.

CONCLUSIONS

The propensity for the development of calcium nephrolithiasis differed markedly among ethnic groups in North America. While environmental factors could not be completely ruled out, this variability may reflect the influence of genetic susceptibility because there was no dominant environmental factor to account for the differences in relative risk of stone disease.

Multi-tract percutaneous nephrolithotomy for large complete staghorn calculi

INTRODUCTION

The treatment of large complete staghorn calculi requires a sandwich combination of percutaneous nephrolithotomy (PCNL) and shockwave lithotripsy (SWL) or sometimes open surgery. Many urologists hesitate to place more than 2-3 tracts during PCNL because of the belief that this may increase complications. We present data to support multi-tract PCNL for large (surface area >3,000 mm(2)) complete staghorn calculi.

PATIENTS AND METHODS

From July 1998 to October 2003, 121 renal units (103 patients) with large complete staghorn renal calculi were treated with PCNL. All procedures were performed in the prone position after retrograde ureteral catheterization. Fluoroscopy-guided punctures were made by the urologist followed by track dilation to 34 french. When multiple tracts were anticipated all punctures were usually made at the outset and preplaced wires were put into the collecting system or down the ureter. Stones were fragmented and removed using a combination of pneumatic lithotripsy and suction. Postoperative stone clearance was documented on X-ray KUB.

RESULTS

121 renal units of 103 patients (15 women and 88 men, mean age 43 years) were treated. Six patients had associated bladder calculi that were treated simultaneously. The stone surface area was 3,089-6,012 (mean 4,800) mm(2). 10 patients (9.7%) had renal insufficiency with a mean (range) serum creatinine of 3.0 (1.5-5.5) mg/dl. The number of tracts required per patient were 2 tracts in 11, 3 tracts in 68, 4 tracts in 39, and 5 tracts in 3, giving a total of 397 tracts in 121 renal units, over a total of 140 procedures (including second-look procedures in 19 renal units). The points of entry of these tracts were 121 upper calyx (30.4%), 178 middle calyx (44.8%), and 98 lower calyx (24.6%). All 121 units had one upper polar access tract of which 92 (76%) were supracostal. Complications were blood transfusion (n = 18), pseudoaneurysm (n = 2), fever (n = 22), septic shock (n = 1) and hydrothorax (n = 3). PCNL monotherapy achieved an 84% complete clearance rate that improved to 94% with SWL in 8 renal units with small residual fragments. Stone compositions were calcium oxalate (91%), uric acid (2%) and mixed (7%).

CONCLUSION

Aggressive PCNL monotherapy using multiple tracts is safe and effective, and should be the first option for massive renal staghorn calculi.