Patients' poor performance status is an independent risk factor for urosepsis induced by kidney and ureteral stones.

This study was aimed to identify the risk factors for urosepsis caused by kidney and ureteral stones. One hundred and nine patients who had kidney or ureteral stones and who were treated with trans-ureteral lithotripsy (TUL) at our institution from 2016 to 2020 were included. We investigated the risk factors for urosepsis caused by kidney or ureteral stones that occurred prior to TUL. Thirty patients (28%) had urosepsis prior to TUL. Patients were divided into a urosepsis group (n = 30, 28%) and a non-urosepsis group (n = 79, 72%). Patients' characteristics (gender, age, performance status [PS] score, presence of diabetes mellitus, and skeletal muscle mass), as well as their stone and urine characteristics (stone size, presence of obstructive ureteral stones, stone composition, and urine and stone cultures), were compared between the two groups. When compared to the non-urosepsis group, patients with urosepsis were more likely to be older (p < 0.001), female (p < 0.001), with lower skeletal muscle mass (p < 0.001) and with poor PSs (p < 0.001). For stone and urine characteristics, infection stones (p = 0.01), positive urine (p < 0.001) and stone culture (p = 0.007) were more often detected in patients with urosepsis. A multivariate analysis showed patients' poor PS to be an independent risk factor for urosepsis due to kidney and ureteral stones (OR = 15.7; 95% CI = 2.2-115, p = 0.007). Our study revealed that the most significant risk factor for urosepsis caused by kidney and ureteral stones was the patients' poor PS.

Determining the true burden of kidney stone disease.

The incidence and prevalence of kidney stones have increased over the past four decades. However, the diagnosis of 'kidney stone' can range from an incidental asymptomatic finding of limited clinical significance to multiple painful episodes of ureteral obstruction with eventual kidney failure. Some general strategies may be useful to prevent the recurrence of kidney stones. In particular, greater attention to kidney stone classification, approaches to assessing the risk of recurrence and individualized prevention strategies may improve the clinical care of stone formers. Although there have been some advances in approaches to predicting the recurrence of kidney stones, notable challenges remain. Studies of kidney stone prevalence, incidence and recurrence have reported inconsistent findings, in part because of the lack of a standardized stone classification system. A kidney stone classification system based on practical and clinically useful measures of stone disease may help to improve both the study and clinical care of stone formers. Any future kidney stone classification system should be aimed at distinguishing asymptomatic from symptomatic stones, clinically diagnosed symptomatic stone episodes from self-reported symptomatic stone episodes, symptomatic stone episodes that are confirmed from those that are suspected, symptomatic recurrence from radiographic recurrence (that is, with radiographic evidence of a new stone, stone growth or stone disappearance from presumed passage) and determine stone composition based on mutually exclusive categories.

Empiric therapy for kidney stones.

Careful phenotyping of patients to classify those with kidney stones has a long and important history in revealing the chemical basis for stone formation. Advances in our genetic understanding of kidney stones will lead to incredible insights regarding the pathophysiology of this common disorder. At this time, both evaluation of urine chemistry and genotyping of patients are extremely useful in the setting of a university and research-based kidney stone clinic. For much of the world, in a more clinically focused setting, these techniques are neither available nor absolutely necessary. Careful implementation of an empiric prescription based on stone composition would have an important effect to reduce stone recurrence in the world's many stone formers. Increased fluid intake, generic dietary manipulations, and prescription of potassium citrate and thiazides are all appropriate empiric therapies for people with calcium and uric acid kidney stones.

Easy-to-use equations for the estimation of urine relative saturation in the assessment of risk of recurrence in urinary stones formers.

It is a fact that recurrence of urinary stones is a common medical problem. One of the key factors used in determining the risk of urinary stone-formation is the urine relative saturation in the major constituents of lithiasis. Nomograms were developed in the 1970's to estimate the relative saturation of urine. We present here easy-to-use mathematical equations derived from these nomograms. These equations can be integrated directly in the LIS of any laboratories, and can be used as a tool in the treatment and prevention of recurrent stone-formation.

Evaluation of low-dose dual energy computed tomography for in vivo assessment of renal/ureteric calculus composition.

PURPOSE: This study aimed to assess the accuracy of low-dose dual-energy computed tomography (DECT) in predicting the composition of urinary calculi. MATERIALS AND METHODS: A total of 52 patients with urinary calculi were scanned with a 128-slice dual-source DECT scanner by use of a low-dose protocol. Dual-energy (DE) ratio, weighted average Hounsfield unit (HU) of calculi, radiation dose, and image noise levels were recorded. Two radiologists independently rated study quality. Stone composition was assessed after extraction by Fourier transform infrared spectroscopy (FTIRS). Analysis of variance was used to determine if the differences in HU values and DE ratios between the various calculus groups were significant. Threshold cutoff values to classify the calculi into separate groups were identified by receiver operating characteristic curve analysis. RESULTS: A total of 137 calculi were detected. FTIRS analysis differentiated the calculi into five groups: uric acid (n=17), struvite (n=3), calcium oxalate monohydrate and dihydrate (COM-COD, n=84), calcium oxalate monohydrate (COM, n=28), and carbonate apatite (n=5). The HU value could differentiate only uric acid calculi from calcified calculi (p<0.001). The DE ratio could confidently differentiate uric acid, struvite, calcium oxalate, and carbonate apatite calculi (p<0.001) with cutoff values of 1.12, 1.34, and 1.66, respectively, giving >80% sensitivity and specificity to differentiate them. The DE ratio could not differentiate COM from COM-COD calculi. No study was rated poor in quality by either of the observers. The mean radiation dose was 1.8 mSv. CONCLUSIONS: Low-dose DECT accurately predicts urinary calculus composition in vivo while simultaneously reducing radiation exposure without compromising study quality.

The new epidemiology of nephrolithiasis.

Historically nephrolithiasis was considered a disease of dehydration and abnormal urine composition. However, over the past several decades, much has been learned about the epidemiology of this disease and its relation to patient demographic characteristics and common systemic diseases. Here we review the latest epidemiologic studies in the field.

[Risk assessment in children with lithogenic kidney stones]. / Evaluatión del perfil de riesgo litógeno en niños con litiasis renal.

OBJECTIVE: The aim of this study was to describe the lithogenic risk profile of pediatric patients with lithiasis. METHODS: We retrospectively analyzed the metabolic studies in 24-hour urine samples in 47 pediatric patients with lithiasis. Biochemical determinations were made in blood and 24-hour urine. Oxalate calcium, brushite, struvite and uric acid salt saturations were calculated. 49 healthy children were used as a control group. RESULTS: No significant differences were found in biochemical blood parameters between children with stones and the group without stones. Calciuria, uricosuria and phosphaturia, oxalate calcium, brushite and uric acid saturations were higher in lithiasic children. In the multivariate analysis, using a logistic regression model, we only found hypercalciuria as lithogenic risk factor. (OR = 1.96 p <0.002). CONCLUSIONS: Urinary metabolic abnormalities and elevated salt saturations in urine are a frequent finding in children with urolithiasis, but in our study we only found hypercalciuria as an independent risk factor for the formation of lithiasis.

An update on percutaneous nephrolithotomy: lessons learned from the CROES PCNL Global Study.

Since its introduction in late 1970's, percutaneous nephrolithotomy (PNL) has undergone an evolution in both equipment and technique. This evolution still continues today in the era of minimally invasive treatment options, and is evidenced by the numerous publications. PNL is generally advantageous in the management of large renal stones (>1.5-2 cm) with high stone-free rates and considerable complication rates. However this technique is especially competing with retrograde intrarenal surgery and laparoscopic techniques. Therefore the CROES Global PNL Study Group prospectively collected data of over 5800 patients managed with PNL worldwide and analyzed the data in detail, producing more than 25 scientific papers. And this update focuses on the lessons learned from the CROES PCNL Global Study.

Insurance status, stone composition, and 24-hour urine composition.

UNLABELLED: Abstract Purpose: We examined the stone composition, 24-hour urinary risk factors, and insurance status in patients evaluated in two regional stone clinics to further investigate the relationship between the socioeconomic status and kidney stone formation. MATERIALS AND METHODS: We performed a retrospective review of stone formers who completed a 24-hour urinalysis as part of a metabolic evaluation for nephrolithiasis. Insurance status was determined by billing records and those with state-assisted insurance (SAI) were compared to patients with private insurance (PI). Multivariate analyses were performed adjusting for known risk factors for stones. RESULTS: Three hundred forty-six patients were included. Patients with SAI (16%) were significantly more likely to be female (55% vs.38%, p=0.026) and younger (43.5 vs.49.2, p=0.003). Among those with stone composition data (n=200), SAI patients were as likely to form calcium phosphate (CaPhos) as calcium oxalate (CaOx) stones (46.9% vs.31.3%, p=0.44). PI patients were significantly less likely to form CaPhos than CaOx stones (10.1% vs.77.4%, p<0.001). On multivariate analysis, among those with calcium stones, the odds of forming CaPhos stones over CaOx stones were ten times higher among SAI patients compared to PI, odds ratio 10.2 (95% CI 3.6, 28.6, p<0.001). Further, patients with SAI had significantly higher urine sodium, pH, and supersaturation of CaPhos, and a lower supersaturation of uric acid compared to patients with PI. CONCLUSIONS: SAI was associated with a greater likelihood of a CaPhos stone composition and increased urinary risk factors for CaPhos stones. These findings may reflect dietary or other unmeasured differences, and have important implications for resource allocation and counseling, as treatment may differ for these groups.

Assessment of stone composition in the management of urinary stones.

Several explanations have been suggested to account for the failure of extracorporeal shockwave lithotripsy (ESWL) treatment in patients with urinary stones, including large stone volume, unfavorable stone location or composition and the type of lithotriptor used. Unfavorable stone composition is considered a major cause of failure of ESWL treatment, and consequently knowledge of the stone composition before treatment is initiated is desirable. Plain abdominal radiographs cannot accurately determine either stone composition or fragility, and although the CT attenuation value in Hounsfield units (HU) (that is, normalized to the attenuation characteristics of water) is useful, this parameter has limited value as a predictor of stone composition or the response to ESWL treatment. By contrast, stone morphology as visualized by CT correlates well with both fragility and susceptibility to fragmentation by ESWL. For patients prone to recurrent calculi, analyses of stone composition are especially important, as they may reveal an underlying metabolic abnormality. The development of advanced imaging technologies that can predict stone fragility is essential, as they could provide extra information for physicians, enabling them to select the most appropriate treatment option for patients with urinary stones.

Assessment of kidney stone and prevalence of its chemical compositions.

Kidney stone analysis is the test done on the stone which cause problems when they block the flow of urine through or out of the kidneys. The stones cause severe pain and are also associated with morbidity and renal damage. There is also no clear understanding on the relative metabolic composition of renal calculi. Hence, the study is aimed to find out the chemical composition of it which can guide treatment and give information that may prevent more stones from forming. The study was carried out on the stones that had been sent to the department of Biochemistry (n = 99; M = 61; F = 38; Mean age: 33.6 +/- 14.4 years) Approximately 98.9% of stones were composed of oxalate, 95.9% of Calcium, 85.8% of phosphate, 62.6% of Urate, 46.4% of Ammonium and very few percentages of Carbonate.

[Economic aspects of evidence-based metaphylaxis]. / Okonomische Aspekte der evidenzbasierten Harnsteinmetaphylaxe.

The calculation model which we developed for the cost of stone therapy and metaphylaxis in Germany some years ago with a social health insurance company is based on estimates of stone incidence, types and recurrence rates, actual costs for stone removal, and metaphylaxis (based on data from a district of the social health care system). There are 200,000 stone recurrences per year in Germany. Costs for treatment of these stones amount to $687,000,000. Stone metaphylaxis reduces the recurrence rate by some 40%. The annual cost for stone removal could be lowered by $275,300,000. Metabolic evaluation/metaphylaxis amount to $70,100,000 per year, resulting in a net saving of $205,200,000. In 1997, there were 96 days off work per stone patient resulting in 5,800,000 days off work in Germany per year. Metaphylaxis is not only medically effective in stone formers but also can lower health care cost significantly. Although health care conditions may vary from country to country, in principle this calculation model is applicable also to other countries.

Management of staghorn calculus: analysis of combination therapy and open surgery.

OBJECTIVE: To assess the role of primary open surgery versus the recommended combination approach (percutaneous and lithotripsy) to treat staghorn calculi in a developing country. PATIENTS AND METHODS: Available records (n = 91) of patients with staghorn managed during the last 4 years were retrieved. Patients were placed in two groups, open surgery and combination group, according to the primary procedure chosen by the patient. Demographic data in two groups was comparable in most of the respects except that renal failure patients were more in the combination group. Stone clearance, major residue, auxiliary procedures, morbidity, hospital stay and the cost were studied in the two groups for comparison. RESULTS: Complete clearance could be obtained in 66 and 59% with open and combination method respectively. Major residue (> 16 mm2) was present in 21% of open and 38% of the combination group. In patients with primary stone burden < 900 mm2, the total clearance rates were 66 and 60% in open and combination group, respectively. Total clearance was not affected by caliceal dilatation, total stone burden, pelvic and caliceal bulk separately or their ratio, as arrived by logistic regression analysis. The incidence of haematuria in the combination group was marginally higher, probably due to more renal failure patients in this group. Hospital stay in the two groups was comparable (13.0 days in combination vs. 12.1 days for open). The cost of treatment with combination group was significantly higher. CONCLUSION: Open surgery for staghorn is still an economically viable option for difficult stone disease, specially in a developing country, with comparable efficacy, favourable morbidity and hospital stay.

Laboratory and clinical assessment of pneumatically driven intracorporeal lithotripsy.

A pneumatically driven intracorporeal lithotripter (the Swiss Lithoclast) has recently been approved for use in the United States. We compared its performance in vitro with ultrasonic, electrohydraulic and laser lithotripsy devices using a standard plaster-of-Paris stone phantom. The probe sizes and output settings were identical to those used during clinical treatment. The fragmentation efficiency index (measured as the lithotripsy time needed to reduce the stone phantom to particles <2 mm divided by the initial stone weight) ranged from 5.0 to 8.5 min/g of stone mass, with this value increasing from pneumatic to electrohydraulic to laser and to ultrasonic lithotripsy. We also performed an objective study in a swine model, which showed no adverse consequence of pneumatic lithotripsy. Finally, we evaluated our initial 41 patients who had undergone pneumatic stone fragmentation. We treated 8 patients having 11 renal calculi, 30 patients having 37 ureteral calculi, and 3 patients having 6 bladder calculi employing pneumatic probes ranging in size from 0.8 to 2.0 mm. Stone fragmentation was successful in a single session in 95% of the ureteral calculi and 100% of both renal and bladder calculi. Stone analysis in 23 patients revealed 17 (74%) calcium oxalate monohydrate and 1 (4%) cystine calculi. Our clinical and laboratory assessment of this newly developed pneumatic lithotripsy device further validates its efficacy in fragmenting stone of all compositions and its overall safety associated with clinical application.

[Treatment of renal and ureteral lithiasis]. / Traitement de la lithiase rénale et urétérale.

The advent of extracorporal shock wave lithotripsy has entirely changed management of patients with renal or ureter calculi. It is indicated in all types of calculi and generally used as first line treatment. Contraindications are exceptional: pregnancy, uncorrectable coagulation disorders. For staghorn calculi in the kidney, lithotripsy alone is only effective in 50% of the cases and is often completed or preceded by percutaneous nephrolithotomy. Classical surgical procedures may be required in complex cases. Success rate (complete stone free with none residual) with lithotripsy is higher for pelvic stones (70%) and small residual fragments are usually asymptomatic and rarely infected. There is still some debate over indications for ureteral calculi although use of in situ lithotripsy with an ureteral probe. The ureteroscopy is more effective for stones in the distal ureter. In all cases, the final factor in the management decisions is cost-effectiveness.

Outcome of extracorporeal shockwave lithotripsy monotherapy for large renal calculi: effect of stone and collecting system surface areas and cost-effectiveness of treatment.

The treatment options for large renal calculi are controversial. We report on our experience with 65 treatments of renal calculi > 3 cm using extracorporeal shockwave lithotripsy (SWL) monotherapy. We stratified our results according to stone and collecting system surface areas (measured by computer image analyses), stone location, and stone type. The overall success rate of SWL monotherapy was 27% at 3 months. The best stone-free rate (60%) was obtained for stones < 500 mm2 and located primarily within the renal pelvis. The stone-free rate for stones with surface areas > 1000 mm2 was only 8%. None of the cystine stones was treated successfully, whereas 80% of patients with uric acid stones became stone free. We estimated an average cost of $67,048 to render a patient with a large renal calculus stone free using SWL monotherapy. We recommend that other treatment options, such as percutaneous nephrolithotomy, be considered as first-line therapy for large renal calculi.

[Piezoelectric extracorporeal lithotripsy in children. Assessment over 3 years]. / La lithotritie extra-corporelle piézo-électrique chez l'enfant. Une évaluation sur 3 ans.

From 1987 to 1990, 45 children whose age ranged from 5 months to 14 years and who presented with urinary lithiasis underwent piezoelectrical extracorporeal lithotripsy with a Piezolith 2,300 and 2,500 system. We were able to perform the treatment without anesthesia in 53% of the children. The results were highly encouraging as, and without any severe complication; 84% of the children had no residual calculus after 3 months.