Análisis de la composición química de litiasis urinaria de 649 pacientes mediante espectroscopía infrarroja, primera experiencia nacional / Chemical composition analysis of 649 urinary stones

Background: Chemical composition analysis of urinary stones is a fundamental part of the metabolic workup of urolithiasis. Aim: To report the chemical composition of urinary stones using infrared spectroscopy. Material and Methods: The chemical composition of rinary stones recovered from 649 patients aged 1 to 97 years (68% males), were analyzed using a Perkin Elmer FTIR Spectrometer, Spectrum Two. Results: Calcium oxalate monohydrate was the most common composition found in 45% of cases, followed by mixed composition, which included three ammonium phosphate stones in 29% of cases. Pure uric acid composition was found in 16% of stones. Three cystine stones were detected. Conclusions: These findings do not differ from those found in developed countries.

Upper urinary tract stone compositions: the role of age and gender

ABSTRACT Objective: To analyze the compositions of upper urinary tract stones and investigate their distributions in different gender and age groups. Materials and Methods: Patients diagnosed with upper urinary tract stone disease between December 2014 and March 2018 were retrospectively reviewed. Patient's age, gender, BMI, comorbidities, stone event characteristics, and compositions were collected, and proportions of stone components in different gender and age groups were analyzed. Results: A total of 1532 stone analyses were performed (992 from males and 540 from females). The mean age was younger in males (p <0.001). Males included more cases with larger BMI, hyperuricemia, and obesity, while females had more urinary tract infections. Multiple components were present in 61.8% of stones. Calcium oxalate (CaOx) (67.0%) was the most common component, followed by uric acid (UA) (11.8%), infection stone (11.4%), calcium phosphate (CaP) (8.0%), cystine (1.1%), brushite (0.4%), and 2, 8-dihydroxyadenine (0.2%). Men contributed with more CaOx stones than women at age 30-49 years (all p <0.01) and more UA stones at 30-59 years (all p <0.05). Women contributed with more infection stones than men in age groups 30-49 and 60-69 years (all p <0.05), and more CaP stones at 30-49 years. The prevalence peak was 50-59 years in men and 60-69 years in women. Both genders had the lowest prevalence in adolescence. Prevalence of UA stones increased while that of infection stones decreased with aging in both genders. Conclusions: Age and sex had a strong association with distribution of stone compositions in this Chinese cohort.

Litiasis renal en Paraguay: herramientas laboratoriales en la identificación de etiología y seguimiento del paciente litiásico / Nephrolithiasis in Paraguay: Laboratory tools in the identification of etiology and follow-up of the lithiasic patient

La litiasis renal es una patología que se caracteriza por la formación, agregación y retención de cristales en las vías urinarias. Su etiología es compleja ya que la misma puede ser el resultado de la interacción de múltiples factores tanto endógeno, metabólico como ambiental. La elevada tasa de recurrencia de la formación de cálculos puede superar el 40% en un periodo de 5 años tras el primer episodio y puede conllevar consecuencias graves para el funcionamiento renal con su consiguiente impacto en la calidad de vida del paciente(AU)

Effect of stone composition on the outcomes of semi-rigid ureteroscopy using holmium: yttrium-aluminum-garnet laser or pneumatic lithotripsy

Objective: To compare the effectiveness of laser lithotripsy [LL] and pneumatic lithotripters [PL] in calcium oxalate [CaOx] and calcium phosphate [CaP] stones and assess whether these stone compositions affect the outcomes of LL and PL

Study Design: Comparative, descriptive study

Place and Duration of Study: Istanbul Training and Research Hospital, Turkey, from August 2010 to August 2015

Methodology: A total of 114 patients underwent ureteroscopy using LL and PL. Fifty-eight [50.9%] had CaOx stones and 56 [49.1%] had CaP stones. The lithotripters were compared in stone composition groups, and stone compositions were compared in lithotripter groups. Patient characteristics, perioperative parameters, and postoperative complications were compared

Results: The baseline patient and stone characteristics were similar in all groups. The operation time of the PL and LL for the patients with CaP stones [68.75 +/- 32.88 and 44.48 +/- 34.37 minutes, respectively] was significantly shorter than the operation time of the PL and LL for the patients with CaOx stones [91.56 +/- 30.54 and 65.75 +/- 37.74 minutes, [p=0.012 and p=0.009, respectively]. Moreover, the patients with CaOx or CaP treated with LL [65.75 +/- 37.74 and 44.48 +/- 34.37 minutes, respectively] had significant shorter operation time than the PL [91.56 +/- 30.54 and 68.75 +/- 32.88 minutes, [p=0.046 and p=0.01, respectively]. Stone-free rates were similar in all groups. The PL for the patients with CaP stones caused more postoperative fever and infection than the other groups [p=0.050]

Conclusion: Though both PL and LL are effective in the treatment of CaOx and CaP stones, LL had a significantly shorter operation and hospitalization time and complication rates in patients with CaOx and CaP stones. So LL is a more feasible and safer modality in the treatment of recurrent CaP stones

Composición de las urolitiasis en pacientes cubanos por sexo / Composition of urolithiasis in Cuban patients by sex

INTRODUCCIÓN: las urolitiasis implican morbilidad y costos económicos sustanciales. Para su manejo resulta fundamental una evaluación clínica y de laboratorio, que incluya el estudio de la composición química. OBJETIVO: determinar la frecuencia de presentación de los diferentes tipos de urolitiasis según su composición y su relación con el sexo de los sujetos. MÉTODOS: estudio descriptivo, transversal. Se incluyeron las urolitiasis de adultos cubanos, enviadas al Laboratorio de Fisiopatología Renal del Instituto de Nefrología para estudio de composición química, en el período 2001-2011. Las litiasis fueron analizadas con un espectroscopio infrarrojo modelo Philips PU9516. Los diferentes compuestos se identificaron mediante comparación con espectros de referencia. Toda la información fue procesada automatizada (SPSS 15.0.). Se utilizó análisis de distribución de frecuencias. Para probar la existencia de diferencias entre los sexos, en cuanto al tipo de litiasis, se emplearon los tests: de independencia y exacto de Fisher. RESULTADOS: de las 1851 litiasis analizadas, 1316 (71,1 %) eran litiasis simples. Las litiasis simples de oxalato de calcio constituyeron el 46,8 % del total. Dentro de las compuestas, las más frecuentes fueron las de oxalato de calcio más fosfato de calcio (24,7 %). La frecuencia de las litiasis de oxalato de calcio y ácido úrico resultó mayor entre los hombres (p= 0,00), y las de fosfato de calcio y de estruvita (p= 0,00), entre las mujeres. CONCLUSIONES: los cálculos cálcicos, fundamentalmente de oxalato de calcio monohidratado, son los más comunes en la población litiásica estudiada. Las litiasis de oxalato de calcio y ácido úrico son más comunes entre los hombres, mientras las de estruvita y fosfato de calcio lo son, entre las mujeres.

INTRODUCTION: urolithiasis imply significant morbidity and economic costs. For its management, it is fundamental to make clinical and lab evaluation including the study of the chemical composition. OBJECTIVE: to determine the frequency of occurrence of several types of urolithiasis according to their composition and relationship with the individual's sex. METHODS: descriptive and cross-sectional study that included urolithiasis of Cuban adults sent to the Renal Physiopathology Lab of the Institute of Nephrology for the study of chemical composition in the 2001-2011 period. A Philips PU9516 infrared spectroscope served to analyze lithiasis. The various compounds were identified by comparing them with the reference spectra. All the data were collected and processed with SPSS 15.0; the frequency distribution analysis. Independence test and Fisher's exact test were used to confirm the differences between sexes in terms of type of lithiasis. RESULTS: of 1815 analyzed lithiasis, 1316 (71.1 %) were simple. Simple calcium oxalate lithiasis represented 46.8 % of the total number. In the combinations, the most frequent were calcium oxalate plus calcium phosphate (24.7 %). The frequency of calcium oxalate and uric acid lithiasis was higher in men (p= 0.00 and those of calcium phosphate and struvite (p= 0.00) in women. CONCLUSIONS: calcium stones, mainly monohydrated calcium oxalate, are the most common in the studied lithiatic population. Calcium oxalate and uric acid are the commonest in men whereas struvite and calcium phosphate are more frequent in women.

In vitro studies reveal antiurolithic effect of Terminalia arjuna using quantitative morphological information from computerized microscopy

ABSTRACT Purpose: For most cases, urolithiasis is a condition where excessive oxalate is present in the urine. Many reports have documented free radical generation followed by hyperoxaluria as a consequence of which calcium oxalate (CaOx) deposition occurs in the kidney tissue. The present study is aimed to exam the antilithiatic potency of the aqueous extract (AE) of Terminalia arjuna (T. arjuna). Materials and Methods: The antilithiatic activity of Terminalia arjuna was investigated in vitro nucleation, aggregation and growth of the CaOx crystals as well as the morphology of CaOx crystals using the inbuilt software ‘Image-Pro Plus 7.0’ of Olympus upright microscope (BX53). Antioxidant activity of AE of Terminalia arjuna bark was also determined in vitro. Results: Terminalia arjuna extract exhibited a concentration dependent inhibition of nucleation and aggregation of CaOx crystals. The AE of Terminalia arjuna bark also inhibited the growth of CaOx crystals. At the same time, the AE also modified the morphology of CaOx crystals from hexagonal to spherical shape with increasing concentrations of AE and reduced the dimensions such as area, perimeter, length and width of CaOx crystals in a dose dependent manner. Also, the Terminalia arjuna AE scavenged the DPPH (2, 2-diphenyl-1-picrylhydrazyl) radicals with an IC50 at 13.1µg/mL. Conclusions: The study suggests that Terminalia arjuna bark has the potential to scavenge DPPH radicals and inhibit CaOx crystallization in vitro. In the light of these studies, Terminalia arjuna can be regarded as a promising candidate from natural plant sources of antilithiatic and antioxidant activity with high value.

Some critical aspects of FT-IR, TGA, powder XRD, EDAX and SEM studies of calcium oxalate urinary calculi.

Urinary calculi constitute one of the oldest afflictions of humans as well as animals, which are occurring globally. The calculi vary in shape, size and composition, which influence their clinical course. They are usually of the mixed-type with varying percentages of the ingredients. In medical management of urinary calculi, either the nature of calculi is to be known or the exact composition of calculi is required. In the present study, two selected calculi were recovered after surgery from two different patients for detailed examination and investigated by using Fourier-Transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), powder X-ray diffraction (XRD), scanning electron microscopy and energy dispersive analysis of X-rays (EDAX) techniques. The study demonstrated that the nature of urinary calculi and presence of major phase in mixed calculi could be identified by FT-IR, TGA and powder XRD, however, the exact content of various elements could be found by EDAX only.

Multimodal Treatments of Cystine Stones: An Observational, Retrospective Single-Center Analysis of 14 Cases

PURPOSE: To document the experiences of a single institution in evaluating the clinical courses and treatment outcomes of patients with cystine stones. MATERIALS AND METHODS: The clinical data of 14 patients with cystine stones who were treated at our institution from March 1994 to July 2012 were reviewed. These data included age at first visit, gender, family history, body mass index, presence of a single kidney, stone locations, stone burden, routine urinalysis, and culture. In addition, we also analyzed data on surgery, shock wave lithotripsy, medical treatment, stone recurrence or regrowth, and overall treatment success rates. RESULTS: The mean age of our patients at their first visit was 19.6+/-5.0 years, and eight patients were males. The median stone burden and mean urine pH before each surgery were 6.5 cm2 and 6.5+/-0.9, respectively. Two patients had a family history of cystine stones. Patients underwent surgery an average of 2.7 times. The median interval between surgeries was 27.3 months, and 1 open surgery, 12 percutaneous nephrolithotomies, and 25 ureterorenoscopies were performed. Potassium citrate or sodium bicarbonate was used in nine cases. D-Penicillamine was continuously used in three patients. Patients had an average incidence of 3.2 recurrences or regrowth of stones during the median follow-up period of 60.5 months. CONCLUSIONS: Patients with cystine stones have high recurrence or regrowth rates and relatively large stone burdens. Adequate treatment schedules must therefore be established in these cases to prevent possible deterioration of renal function.

Changes in Urinary Stone Composition in the Tunisian Population: A Retrospective Study of 1,301 Cases

BACKGROUND: Studies that evaluate the effect of age on stone composition are scarce. The aim of this study was to highlight the changes in epidemiological characteristics (stone composition and location) of urolithiasis according to patients' age. METHODS: We studied 1,301 urolithiasis patients with age ranging from 6 months to 92 yr (781 males and 520 females). Stone analysis was performed using a stereomicroscope and infrared spectroscopy to determine the morphological type and molecular composition of each stone. RESULTS: The annual average incidence of new stone formation was 31.7 per 100,000 persons. In 71.8% of cases, calculi were located in the upper urinary tract. Compared to other age groups, children and old men were more affected by bladder stones. Calcium oxalate monohydrate was the most frequent stone component, even though its frequency decreased with age (59.5% in young adults and 43.7% in the elderly, P<0.05) in favor of an increase in uric acid stones (11.5% in young adults and 36.4% in the elderly, P<0.05). Struvite stones were rare (3.8%) and more frequent in children than in adults. CONCLUSIONS: The analysis of these data showed that urinary stones in Tunisian patients are tending to evolve in the same direction as the stones in patients from industrialized countries.

Growth inhibition of struvite crystals by the aqueous root extract of Rotula aquatica.

Formation of urinary stone is a serious and debilitating problem throughout the world. In the present study, the inhibitory effect of aqueous extract of root of Rotula aquatica was investigated against struvite crystals (one of the components of urinary stone) grown in vitro using single diffusion gel growth technique. For setting the gel, sodium metasilicate solution (specific gravity 1.05) and 0.5 M aqueous solution of ammonium dihydrogen phosphate were mixed, so that the pH of the mixture could be set at 7.0. Equal amounts of supernatant solution of magnesium acetate (1.0 M) prepared with 0.0%, 0.5% and 1% concentrations of the extract were gently poured on the set gels. It was observed that the number, dimension, total mass, total volume, growth rate and depth of growth of struvite crystals decreased with the increasing extract concentrations in the supernatant solutions. The enhancement of dissolution rate and fragmentation of struvite crystals suggested potential application of the extract for inhibition of struvite type urinary stone.

Metabolic factors associated with urinary calculi in children

We aimed to identify metabolic and anatomical abnormalities present in children with urinary calculi. Metabolic evaluation was done in 142 pediatric calculus formers. Evaluation included serum biochemistry; measurement of daily excretion of urinary calcium, uric acid, oxalate, citrate, and magnesium [in older children]; and measurement of calcium, uric acid, oxalate, and creatinine in random urine samples in nontoilet-trained patients. Urinary tests for cystinuria were also performed. All of the patients underwent renal ultrasonography. Sixty-one patients [42.7%] had metabolic abnormalities. Anatomical abnormalities were found in 12 patients [8.4%]. Three children [2.1%] had infectious calculi, and 3[2.1%] had a combination of metabolic and anatomic abnormalities. In 66 children [46.2%] we did not find any reasons for calculus formation [idiopathic]. Urinalysis revealed hypercalciuria in 25 [17.6%], hyperuricosuria in 23 [16.1%], hyperoxaluria in 17 [11.9%], cystinuria in 9 [6.3%], hypocitraturia in 3 [2.1%], and low urinary magnesium level in 1 [0.7%] patients. Sixteen patients [11.2%] had mixed metabolic abnormalities. Metabolic abnormalities are common in pediatric patients with urinary calculi. In our study, calcium and uric acid abnormalities were the most common, and vesicoureteral reflux seemed to be the most common urological abnormality which led to urinary stasis and calculus formation

Análise química do cálculo em pacientes portadores de litíase do trato urinário / Chemical analysis of stone in patients with nephrolithiasis

Introdução: Nefrolitíase é uma doença multifatorial que se relaciona com desordens genéticas e fatores ambientais. Cálculos são mais comuns em adultos e são associados com diversas desordens metabólicas. Os cálculos de oxalato de cálcio são os mais comuns. O objetivo deste estudo é realizar a análise química dos cálculos urinários em nossa região. Materiais e Métodos: Realizamos um estudo retrospectivo em 1.342 pacientes com evidência recente de formação de litíase urinária. A investigação laboratorial consistiu da análise química dos cálculos que estiveram disponíveis. Resultados: Foram atendidos 1.342 pacientes com nefrolitíase, sendo que somente 109 (8,1%) foram submetidos à análise química do cálculo. Nestes, a idade média era de 38,9 ± 13,4 anos, sendo 55 (50,5%) do sexo masculino. História familiar positiva ocorreu em 65% dos casos. Cálculos de oxalato de cálcio foram encontrados em 87% dos casos analisados. Hipercalciúria foi o distúrbio metabólico mais encontrado nos pacientes com cálculos de oxalato de cálcio (60%). Conclusões: A análise química do cálculo mostrou que o oxalato de cálcio é o constituinte mais encontrado em nossa região, e estes dados estão de acordo com a literatura.

Introduction: Nephrolithiasis is a multifactorial disease and it has relation with genetic disorders and environmental factors. Stones are most common in adults and are associated with several metabolic disorders. Calcium oxalate is the most common type of stone. The objective of this study is to evaluate chemical analysis of calculi in our region. Methods: We made a retrospective study on 1,342 patients with evidence of recent formation of renal stones. Laboratory investigation included chemical analysis when the stones were available. Results: 1,342 patients with nephrolithiasis were consulted, among whom only 109 (8.1%) were submitted to chemical analysis of stones. Mean age of those patients were 38.9+13.4 years, and 55 (50.5%) were male. Familial history occurred in 65% of the cases. Calcium oxalate stones were found in 87% of the cases. Hypercalciuria and hyperuricosuria were the most associated metabolic disturb in patients with calcium oxalate and uric acid in the stones (60%). Conclusions: Chemical analysis has demonstrated that calcium oxalate is the most common component found in our region, according to the literature.

Chemical composition of urinary tract stones at the University Hospital of the West Indies / Composición química de las piedras del tracto urinario en el Hospital Universitario de West Indies

Urinary tract stones occur frequently with the incidence being about one to fifteen per cent worldwide. Patients may be asymptomatic or sometimes they may present with haematuria. Severe lumbar pain radiating to the loin requiring immediate analgesic treatment may occur. Stones generally consist of organic and inorganic material. The organic material may be present in the nidus and can contribute up to about 2.5% of the total weight. Inorganic minerals make up the bulk of the stone. Data are presented for the inorganic minerals present in the stones seen at the University Hospital of the West Indies over a 25-year period. Six hundred and forty-one (445 males and 196 females) stones were analyzed by routine chemical methods. Calcium was the main constituent, being seen in 93.9% of the stones. This was followed by oxalate 60.1%, urate 37.0%, bicarbonate 16.5% and magnesium 8.6%. There were four cystine containing stones. Treatment includes medical management for the underlying cause and surgical methods for the removal of the stones. Chemical methods of analysis of the stones has its limitations and should be replaced by more sophisticated methods eg X-ray diffraction crystallography which would give more accurate details of the structure of the stones.

Las piedras del tracto urinario se presentan frecuentemente con una incidencia de aproximadamente uno a quince por ciento a nivel mundial. Los pacientes pueden ser asintomáticos o presentarse con hematuria. Puede producirse dolor lumbar severo que se irradia a toda la región lumbar y que requiere tratamiento analgésico inmediato. Las piedras generalmente están formadas por material orgánico e inorgánico. El material orgánico puede estar presente en el nido y puede contribuir hasta aproximadamente 2.5% del peso total. Los minerales inorgánicos constituyen la mayor parte de las piedras. Se presentan datos de los minerales inorgánicos presentes en las piedras vistas en el Hospital Universitario de West Indies en un periodo de 25 años. Seiscientos cuarenta y una (445 varones y 196 hembras) piedras fueron analizadas mediante métodos químicos de rutina. El calcio fue el constituyente principal, observándosele en el 93.9% de las piedras. El mismo fue seguido por el oxalato (60.1%), el urato (37.0%), el bicarbonato (16.5%) y el magnesio (8.6%). Había cuatro cistinas que contenían piedras. El tratamiento incluye el manejo médico de la causa subyacente y los métodos quirúrgicos para la eliminación de las piedras. Los métodos químicos de análisis de las piedras tienen sus limitaciones y deben reemplazarse por métodos más sofisticados, tales como la cristalografía por difracción de rayos X. que daría detalles más exactos de la estructura de las piedras.

Study of calcium regulating hormones in calcium stone formers

The present study demonstrated that calcium stone formers possesses significant decrease in 1.25 [OH]2 Vit D; 24, 25 [OH]2 Vit D and Vit. D binding protein as compared to control. This finding is accompanied with high activity of alkaline phosphatase due to bone fraction elevation, and serum hypocalcaemia as well as hypophosphataemia. The interesting finding was the inactivation of superoxide dismutase [SOD] couple with hypercalciuria, and elevation of urine citric acid content

Physical, X-ray diffraction and scanning electron microscopic studies of uroliths.

Identification of chemical constituents of calculus is important in the diagnosis and management of urolithiasis. The compositional variability of uroliths has different etiologies and requires various modes of treatment and prophylaxis. In the present study, we report the chemical compositional analyses of calculi recovered from buck and bullock by X-ray diffraction (XRD) and energy dispersive X-ray (EDX) techniques and ultra-structure examination by scanning electron microscopy (SEM). XRD and EDX investigations conclusively established the chemical compositions of urinary calculi under investigation. The calculus from buck (sample I) had calcium oxalate monohydrate, a dominant salt phase and magnesium compound in significant amount. The calculus from bullock (sample II) had magnesium ammonium phosphate phase, with significant amount of calcium in apatite form and K+ ions. SEM study at higher magnification (X 1000) showed bipyramidal crystals in external zones of urolith (sample I). The struvite apatite calculus showed that basic unit of structure was lamination and the laminitis appeared to be made up of fine granules and high porosity. The bio-mineralization process of calculus formation was also studied, with a view to take preventive and therapeutic measures for amelioration of urinary stone diseases in animals and humans.

review of urinary stone analysis techniques

Knowledge of the chemical composition and structure of urinary stones is of great value in the choice of treatment and prevention of recurrence. This is a brief review and a comparative study of the principles and practical application of various chemical and physical techniques used for urinary stone analysis. The different methods of classifying and grouping urinary stones by results of chemical analytic techniques are, also, compared and evaluated. In addition to reviewing various techniques used for the in-vitro analysis of removed stone samples, the newly emerging physical and radiological techniques for the in-vivo intact-stone analysis are, also, evaluated. These in-vivo techniques, particularly the rapidly advancing unenhanced spiral CT scanning, represent an important step forward towards the notion of non- destructive analysis of urinary stones while still in situ before the choice of treatment modality

Prevalence and etiology of urinary stones in hospitalized patients in Baghdad

Epidemiology and pathogenesis in urinary stones diagnosed in 184 patients were studied. Mean age was 38.3 years. Male to female ratio was 2.5: 1. Stones were predominantly of mixed type: calcium oxalate was the commonest compound. Anatomical distribution of urinary stones was 67.4% renal, 12.5% ureteric and 14.6% bladder. Recurrence rate following previous surgical removal was 15.0%. Bacteria were isolated from 19 [24.4%] of 78 urinary stones: 14 were urea splitting and 5 non-urea splitting. Females had a greater chance of having infected stones. All bacteria isolated were sensitive to gentamicin and nalidixic acid. All isolates were resistant to amoxicillin and erythromycin. Multiple resistance to 6 antimicrobial agents was common [58.8%]

Urinary tract calculi: a four years' experience

To study the pattern and management of urolithiasis. This retrospective observational study was carried out at surgical D unit of Khyber Teaching Hospital, Peshawar, from January 2001 to December 2004. Data of 852 patients with urolithiasis, managed in the surgical unit in the four years period was evaluated. Information regarding age, sex, side, site, type of operation and chemical nature of the calculi was recorded on a proforma. Metabolic study was done in only selected cases. During the study period, 852 patients with urolithiasis were managed. Out of these, 577 [67.72%] were male and 275 [32.28%] were female, with male to female ratio of 1.2:1. Patients between 1 year and 85 years of age were operated. Maximum number of patients was between 3rd and 5th decade of life. Majority of the patients belonged to lower middle and poor socioeconomic groups. Chemical analysis showed calcium oxalate in 503 [60%] cases followed by uric acid in 126 [15%] cases. All the patients underwent open surgical procedures except 34 [3.9%] patients who had litholapexy, 5 [0.6%] patients had lithotripsy after insertion of double J stent. Thirteen [1.5%] patients .underwent nephrectomy for renal stone disease. Urolithiasis is a fairly common disease. Commonest calculi found were calcium oxalate

Is stone radiodensity a useful parameter for predicting outcome of extracorporeal shockwave lithotripsy for stones <= 2 cm?

PURPOSE: Several factors determine the success of extracorporeal shockwave lithotripsy (SWL) for kidney stones: stone size, stone location within the collecting system, stone type, and the SWL machine used. It has been suggested that stone radiodensity, as determined either by plain radiography or computed tomography attenuation values, may be an independent predictor of SWL success. We examined the outcome of SWL for solitary stones less than or equal to 2 cm located within the renal pelvis, based on their radiodensity. MATERIALS AND METHODS: 211 patients with solitary renal pelvic stones measuring less than or equal to 2 cm were treated on a Dornier Doli 50 lithotriptor under general anesthesia. The radiodensity of the stone was determined to be either less than, equal to, or greater than the radiodensity of the ipsilateral 12th rib. Stone-free rates (SFR) were determined at 3 months by kidney, ureters and bladder (KUB) plain X-rays. Patients requiring re-treatment or auxiliary procedures were considered failures of SWL. RESULTS: Follow-up SFR information was available in all 211 patients. Stone composition was available in 158 (75 percent) treated patients, but no correlation was found between stone radiodensity and stone composition. For stones <= 10 mm within the renal pelvis, the SFRs were similar (71 to 74 percent regardless of stone radiodensity). For stones between 11 and 20 mm, the SFR was 60 percent if the stone had a radiodensity > 12th rib compared to a SFR of 71 percent if the stone radiodensity was <= 12th rib. However, these differences in SFRs were not statistically significant. CONCLUSIONS: On the Doli machine, stone radiodensity alone does not predict lithotripsy treatment outcome for stones <= 1 cm within the renal pelvis. This parameter is probably only useful as the stone size becomes larger than 1 cm, and should be used in conjunction with other stone parameters to select appropriate therapy.