2022 Recommendations of the AFU Lithiasis Committee: Epidemiology, stone analysis and composition.

The incidence of urinary lithiasis is rising steadily in industrialized countries, and its prevalence in the general population of France is estimated at 10%. Renal colic accounts for 1-2% of emergency department consultations. At a time when the new LASER stone fragmentation techniques available to urologists will lead to ever finer in situ pulverization of stones, the exact identification of the compounds that form the stone is essential for etiological diagnosis. Constitutional analysis by infrared spectrophotometry or X-ray diffraction is therefore recommended, to be complemented by morphological typing of the calculi. METHODOLOGY: These recommendations have been drawn up using two methods: the Recommendation for Clinical Practice (RPC) method and the ADAPTE method, depending on whether or not the issue was considered in the EAU recommendations (https://uroweb.org/guidelines/urolithiasis) [EAU 2022] and their adaptability to the French context.

Morbidity and long-term results of subcutaneous pyelovesical bypass in chronic ureteral obstruction.

BACKGROUND: We present the long-term results and complications of the DETOUR® prosthesis, a permanent subcutaneous pyelovesical bypass for the treatment of ureteral obstruction. PATIENTS AND METHODS: Between 2006 et 2018, 34 prosthesis were implanted in 28 patients (mean age 65,8 years) with ureteral obstruction of malignant or benign etiologies. The prosthesis, composed to an inner tube of silicone and an outer tube of expanded polytetrafluoroethylene, is placed subcutaneously between the kidney and the bladder. We are performed infrared spectrophotometry and scanning electron microscopy on two removed prostheses to explore the prosthetic encrustation. RESULTS: The average follow-up was 25,8 months (Maximum: 64 months). Stent revision was required for early bladder fistula in three patients. The major long-term complications were infection (46%), obstruction (3 patients) and bladder fistula (7 patients). The most frequently infection are non-severe, but two patients died from septic shock after fungic colonization of the prosthesis. The infrared spectrophotometry and scanning electron microscopy analysis showed that the obstruction was favored by urinary infection and an alkaline medium. The functional prosthesis rate at 1,2 and 3 years was 94%, 71% and 62%, respectively. CONCLUSION: The DETOUR® subcutaneous extra-anatomical urinary bypass is an effective and minimally invasive alternative to permanent percutaneous nephrostomy, for both malignant and benign ureteral obstructions in selected patients. LEVEL OF EVIDENCE: 3.

Physicochemical characterization of inorganic deposits associated with granulomas in cutaneous sarcoidosis.

BACKGROUND: Sarcoidosis, characterized by epithelioid granulomas, is considered to be caused by a complex interplay between genetics and environmental agents. It has been hypothesized that exogenous inorganic particles as crystalline silica could be a causal or adjuvant agent in sarcoidosis onset. OBJECTIVES: To investigate the location, frequency and physicochemical characteristics of foreign materials and mineral tissue deposits in the granulomatous area of cutaneous sarcoidosis. METHODS: Skin biopsies (n = 14) from patients diagnosed with cutaneous sarcoidosis (mean age 43 years; 11 patients with extracutaneous involvement) were investigated using polarized light examination (PLE), µFourier Transform Infra-Red (µFT-IR) spectroscopy and Field Emission Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (FE-SEM/EDX). RESULTS: Combined PLE, µFT-IR, FE-SEM/EDX analysis allowed to characterize mineral deposits in 7/14 biopsies (50%). It identified crystalline silica (SiO2 ) inside granulomas in three biopsies and calcite (CaCO3 ) at their periphery in 4. CONCLUSION: This study emphasizes the need of using combined methods for assessment of mineral deposits in granulomatous diseases. According to the location and characteristics of deposits, we can hypothesize that SiO2 particles contribute to the granuloma formation, whereas CaCO3 deposits are related to the granuloma biology. However, the significance of the association between SiO2 deposits and sarcoidosis is still disputed.

Pediatric urolithiasis in Morocco: Composition of 432 urinary calculi analyzed by infrared spectroscopy.

PURPOSE: Incidence of pediatric urolithiasis is decreasing in most developing countries where endemic bladder stones are less prevalent than in the past years. In parallel, stone composition has changed. Only few data are available in North Africa, except for Tunisia. We report stone composition in the Moroccan pediatric population. MATERIAL AND METHODS: Composition of 432 stones from children (302 boys, 130 girls) was determined by infrared spectroscopy. The samples were collected during the period 1999-2016. Stone morphology, which is an important aspect for etiology was determined by examination of each stone under a stereomicroscope. Stone composition was compared to patients' age and gender. RESULTS: The global male-to-female ratio was 2.32. Regarding stone composition, calcium oxalate was the main component in 51.6% of the stones, followed by struvite (18.1%), ammonium urate (9.5%) and carbapatite (9%). Significant differences were found between males and females: calcium oxalate accounted for 72.3% of stones in girls and 42.7% in boys (P<10-6); conversely, struvite was more frequent in boys than in girls (22.2 vs 8.5%, P<10-4). The same was found for calcium phosphate stones (11.9% in boys; 4.6% in girls, P<0.05). Stone morphology helped us for detecting several pathological conditions: type Ic whewellite stones, as a marker for primary hyperoxaluria, was found in 17.6% of stones and type IIId ammonium urate stones, suggestive for infectious diarrhea, was identified in 20.1% of all stones. CONCLUSION: This is the largest series of pediatric stones in Morocco studied by infrared analysis and morphological examination. LEVEL OF EVIDENCE: 3.

[The role of physicochemistry in urology and nephrology, selected results obtained during the last ten years]. / La place de la physicochimie en urologie et en néphrologie : le bilan de 10ans de collaboration entre physiciens, chimistes et praticiens hospitaliers.

INTRODUCTION: The presence of pathological calcifications, which can be either concretions or ectopic call for physicochemical characterisation techniques in order to define a significant diagnosis. The aim of this review is to present a set of characterisation techniques able to describe at the micrometer scale their structural and chemical characteristics and show their place at the hospital. METHOD: Results already published in the last ten years based on characterisation techniques present in laboratories or specific to large-scale instruments are presented. Their usefulness for the clinician is discussed. RESULTS: The presence and role of heavy metals in urinary stones through data collected through µX-ray fluorescence is debated. If these data suggest a simple substitution process of calcium, recent data suggest that weddellite is associated to a Zn-rich environment, partly favoured by an inflammation process. Investigation on the chemistry and the structure of unusual deposits in kidney biopsies show a great chemical diversity of ectopic calcifications. Such diversity shows that staining procedures to characterize such deposits are obsolete. Finally, several diseases which can be assessed through techniques specific to large-scale instruments and defined by the clinician are presented. CONCLUSION: The chemical and structural complexity of pathological calcifications call for a characterization through physicochemical techniques. Only such approach allows the clinician to define a significant diagnosis and to care the patient.

[Composition of 359 kidney stones from the East region of Algeria]. / Détermination de la composition de 359 calculs du haut appareil urinaire collectés dans la région Est-algérien.

PURPOSE: Determine stones composition of the upper urinary tract in the eastern region of Algeria. METHODS: Our study focuses on a set of 359 stones of the upper urinary tract collected between January 2007 and December 2012 at hospitals in the eastern region of Algeria and analyzed by Fourier transform infrared spectroscopy. RESULTS: The male/female ratio was only 1.32. Calcium oxalate prevailed in 68.5% of stones and 49.3% of nuclei, mainly as whewellite (51.8% of stones and 37.9% of nuclei vs 16.7% and 11.4% respectively for weddellite). Carbapatite prevailed in 15% of stones and 29.8% of nuclei. The struvite, identified in 11.1% of calculi, prevailed in 3.9% of stones and 3.1% of nuclei. Among purines, uric acid prevailed with frequencies quite close to 8.9% and 7% respectively in the stone and in the nucleus while the ammonium urate prevailed in only 0.3% of stones and 3.3% of nuclei. The cystine frequency was 3.6% in both stone and nucleus. The frequency of stone with umbilication was 26.2%. Whewellite was the main component of umbilicated stones with Randall's plaque. CONCLUSION: Our results suggest that stones of the urinary tract in the Algerian east region resemble those observed in industrialized countries. Some features such as stones location, the whewellite prevalence, the frequencies of main components in both the stone and the nucleus as well as the formation of stones on renal papilla confirm this trend. LEVEL OF EVIDENCE: 4.

[Presence and role of trace elements in urinary calculi]. / Nature et rôle des éléments traces dans les calculs urinaires.

AIM: To assess the possible nature and role of trace elements in the pathogenesis of urinary stones. MATERIAL AND METHOD: A series of 76 calculi from the East-Algerian region has been investigated through Fourier transform infrared spectroscopy for chemical analysis and X-ray fluorescence for detecting trace elements. RESULTS: Among the detected trace elements, Zn, Sr, Pb, Cu, Rb and Se, only the first three had significant values. Overall, the calcium components, namely calcium oxalate and calcium phosphate, were the most loaded by these elements contrary to organic components such as uric acid and cystine, which had low contents. CONCLUSION: The correlation of contents of Zn and Sr with the stone components (carbapatite, weddellite and whewellite) suggests an adsorption of these trace elements in the case of calcium stones rather than a catalytic process. LEVEL OF EVIDENCE: 3.

[Urinary tract infections: Economical impact of water intake]. / Infections des voies urinaires : impact économique de la consommation d'eau.

BACKGROUNDS: This study aims to estimate the impact of preventing urinary tract infections (UTI), using a strategy of increased water intake, from the payer's perspective in the French health care system. METHODS: A Markov model enables a comparison of health care costs and outcomes for a virtual cohort of subjects with different levels of daily water intake. The analysis of the budgetary impact was based on a period of 5years. The analysis was based on a 25-year follow-up period to assess the effects of adequate water supply on long-term complications. RESULTS: The authors estimate annual primary incidence of UTI and annual risk of recurrence at 5.3% and 30%, respectively. Risk reduction associated with greater water intake reached 45% and 33% for the general and recurrent populations, respectively. The average total health care cost of a single UTI episode is €1074; for a population of 65 millions, UTI management represents a cost of €3.700 millions for payers. With adequate water intake, the model indicates a potential cost savings of €2.288 millions annually, by preventing 27 million UTI episodes. At the individual level, the potential cost savings is approximately €2915. CONCLUSIONS: Preventing urinary tract infections using a strategy of adequate water intake could lead to significant cost savings for a public health care system. Further studies are needed to assess the effectiveness of such an approach.

Recurrent 2,8-dihydroxyadenine nephropathy: a rare but preventable cause of renal allograft failure.

Adenine phosphoribosyltransferase (APRT) deficiency is a rare autosomal recessive enzyme defect of purine metabolism that usually manifests as 2,8-dihydroxyadenine (2,8-DHA) nephrolithiasis and more rarely chronic kidney disease. The disease is most often misdiagnosed and can recur in the renal allograft. We analyzed nine patients with recurrent 2,8-DHA crystalline nephropathy, in all of whom the diagnosis had been missed prior to renal transplantation. The diagnosis was established at a median of 5 (range 1.5-312) weeks following the transplant procedure. Patients had delayed graft function (n=2), acute-on-chronic (n=5) or acute (n=1) allograft dysfunction, whereas one patient had normal graft function at the time of diagnosis. Analysis of allograft biopsies showed birefringent 2,8-DHA crystals in renal tubular lumens, within tubular epithelial cells and interstitium. Fourier transformed infrared microscopy confirmed the diagnosis in all cases, which was further supported by 2,8-DHA crystalluria, undetectable erythrocyte APRT enzyme activity, and genetic testing. With allopurinol therapy, the allograft function improved (n=7), remained stable (n=1) or worsened (n=1). At last follow-up, two patients had experienced allograft loss and five had persistent chronic allograft dysfunction. 2,8-DHA nephropathy is a rare but underdiagnosed and preventable disorder that can recur in the renal allograft and may lead to allograft loss.

[First-line screening guidelines for renal stone disease patients: a CLAFU update]. / Bilan métabolique et prise en charge médicale de la lithiase: une mise au point du CLAFU.

This text summarizes the CLAFU first-line screening guidelines for renal stone disease patients. We have focused on the useful information provided by renal stone analysis and also the identification of relevant stone risk factors detected in a 24-hour urine collection. Indeed, evaluation of water, sodium and protein intake may be easily achieved in a current clinical setting and allows a useful pedagogic tool for patients' advices and follow-up: daily diuresis above 2000 mL, calcium intake between 800 mg and 1 g/day, a moderate daily sodium and proteins restricted diet (<9 g and <1.2 g/kg per day respectively). General therapeutical principles are reviewed, including circumstances requiring specialized management.

Increased water intake as a prevention strategy for recurrent urolithiasis: major impact of compliance on cost-effectiveness.

PURPOSE: We evaluated the economic impact of preventing recurrent stones using a strategy of increased water intake and determined the impact of compliance on cost-effectiveness for the French health care system. MATERIALS AND METHODS: A Markov model was constructed to compare costs and outcomes for recurrent kidney stone formers with less than 2 L vs 2 L or more daily fluid intake. Model assumptions included an annual prevalence of 120,000 stone episodes in France, 14.4% annual risk of stone recurrence and a 55% risk reduction in subjects with adequate water intake. Costs were based on resource use as estimated by a panel of experts and official national price lists. Outcomes were from the perspective of the public health payer, and encompassed direct and indirect costs. RESULTS: The total cost of an episode of urolithiasis was estimated at €4,267 including the cost of treatment and complications. This corresponds to an annual budget impact of €88 million for recurrent stones based on 21,000 stone events. Assuming 100% compliance with fluid intake recommendations of 2 L daily, 11,572 new stones might be prevented, resulting in a cost savings of €49 million. Compliance with water intake in only 25% of patients would still result in 2,893 fewer stones and a cost savings of €10 million. Varying the costs of managing stones had a smaller impact on outcomes since in many patients stones do not form. Varying the incidence of complications did not change the incidence of stones and had a negligible effect on overall cost. CONCLUSIONS: Preventing recurrent urolithiasis has a significant cost savings potential for a payer as a result of a reduced stone burden. However, compliance is an important factor in determining cost-effectiveness.

[Effect of plant extracts on the in vitro dissolution of cystine stones: a study at the mesoscopic scale]. / Effet des extraits de plantes médicinales sur la dissolution des calculs rénaux de cystine in vitro : étude à l'échelle mésoscopique.

AIM: Assessing the efficacy to dissolve cystine stones in vitro of plant extracts used in traditional medicine to treat or prevent urolithiasis. MATERIAL AND METHOD: Pure cystine stones were incubated during 8 weeks under magnetic stirring in the presence of four plant extracts or of NaCl 9 g/l solution used as control. Plants under examination were Arenaria ammophila (leaves and stems), Parietaria officinalis (leaves and flowers studied separately), Paronychia argentea (flowers). Each experiment was performed in triplicate. The mass loss of the stones and the pH of the solution were measured after each two weeks period. Possible changes in the cystine crystals at the stone surface were assessed at the mesoscopic scale using a scanning electron microscope. RESULTS: None of the plant extracts has revealed a significant effect to dissolve cystine stones by comparison to the control during the time of the experiment. The best result was a mass loss of 99 mg at the end of experiment in the presence of A. ammophila vs. 43.7 mg for the NaCl solution (P=0.051). Considering the slopes of the dissolution, only that extract could have an actual efficacy on a more prolonged period. CONCLUSION: Our study failed to demonstrate a significant effect of the tested plant extracts to dissolve cystine stones in vitro. However, the examination of the dissolution curves suggests that a more prolonged test period could allow an efficacy of some extracts, especially A. ammophila. Further studies are needed to verify such hypothesis. However, we cannot recommend the use of the tested plants to treat cystine stones in vivo.

The status of strontium in biological apatites: an XANES investigation.

Osteoporosis represents a major public health problem and increases patient morbidity through its association with fragility fractures. Among the different treatments proposed, strontium-based drugs have been shown to increase bone mass in postmenopausal osteoporosis patients and to reduce fracture risk. While the localization of Sr(2+) cations in the bone matrix has been extensively studied, little is known regarding the status of Sr(2+) cations in natural biological apatite. In this investigation the local environment of Sr(2+) cations has been investigated through XANES (X-ray absorption near-edge structure) spectroscopy in a set of pathological and physiological apatites. To assess the localization of Sr(2+) cations in these biological apatites, numerical simulations using the ab initio FEFF9 X-ray spectroscopy program have been performed. The complete set of data show that the XANES part of the absorption spectra may be used as a fingerprint to determine the localization of Sr(2+) cations versus the mineral part of calcifications. More precisely, it appears that a relationship exists between some features present in the XANES part and a Sr(2+)/Ca(2+) substitution process in site (I) of crystal apatite. Regarding the data, further experiments are needed to confirm a possible link between the relationship between the preparation mode of the calcification (cellular activity for physiological calcification and precipitation for the pathological one) and the adsorption mode of Sr(2+) cations (simple adsorption or insertion). Is it possible to draw a line between life and chemistry through the localization of Sr in apatite? The question is open for discussion. A better structural description of these physiological and pathological calcifications will help to develop specific therapies targeting the demineralization process in the case of osteoporosis.

7,9-Bis(hy-droxy-meth-yl)-7H-purine-2,6,8(1H,3H,9H)trione.

The structure of the title uric acid derivative, C(7)H(8)N(4)O(5), from human kidney stones, is characterized by the C and O atoms of one of the two hy-droxy-methyl groups being disordered nearly equally over three different sites. In the crystal, mol-ecules are connected by a three-dimensional hydrogen-bonding scheme though they look stacked in planes nearly parallel to ([Formula: see text]04).

[Multiple sclerosis and urolithiasis]. / Lithiase urinaire et sclérose en plaques.

OBJECTIVE: The aim of our study was to determine the nature of urinary stones and the main lithogenic process in patients with multiple sclerosis who developed secondary urolithiasis. PATIENTS AND METHOD: This is a retrospective study of 60 urinary stones from 49 patients with lithiasis including 30 women and 19 men. The stones have been analyzed by optical microscopy and infrared spectroscopy. RESULTS: Our study clearly showed the net preponderance of phosphatic stones. Urinary stones were mainly located in the upper urinary tract (2/3 of cases). A particularly high frequency of struvite was observed among these stones (65% of cases in women and 45% of cases in men), thus suggesting the main lithogenic mechanism in multiple sclerosis patients was a urinary tract infection by urea splitting-bacteria. The second lithogenic process among these patients was metabolic. The high frequency of weddellite and brushite, especially in men, suggested that mainly hypercalciuria was involved in these metabolic stones. CONCLUSION: Urolithiasis in multiple sclerosis was mainly due to urinary tract infection, especially in women. Urinary tract infection related to bladder and sphincter disorders is extremely frequent and polymorphic in multiple sclerosis. Hence the importance of providing appropriate care to prevent complications of urinary tract infections and, especially, the ascending migration of microorganisms and the risk of pyelonephritis and of infectious kidney stones.

[In vitro study of the litholytic effects of herbal extracts on cystine urinary calculi]. / Étude in vitro de l'activité litholytique de quatre plantes médicinales vis-à-vis des calculs urinaires de cystine.

INTRODUCTION: cystine stones represent 1% of urinary calculi in adults and 10% in children and are especially recurrent and resistant to ESWL. Medical therapy is often efficient but often poorly tolerated. In Morocco, various plants, Herniaria hirsuta, Opuntia ficus-indica, Zea mays and Ammi visnaga are proposed against nephrolithiasis. We assessed the effect of plant extracts on the disolution of cystine stones in vitro. MATERIAL AND METHOD: an extract of each plant was prepared by infusion of two grams of powdered plants during 30 minutes in 100ml of a boiled NaCl 9 g/L aqueous solution. Each extract was then filtered and thereafter set in a flask containing a cystine stone. The medium was maintained under stirring during 8 weeks. NaCl 9 g/L solution and sodium citrate 3 mmol/L solution were used as controls. At the end of each two weeks period, the stone was removed from the experimental medium and weighted after a 16h drying period at 40°C. RESULTS: after 8 weeks of experiment, stone dissolution was complete for all herbal extracts, and was earlier in the presence of Zea mays (4 weeks) or of Ammi visnaga (6 weeks) by comparison to only 18 ± 8 and 20 ± 1.5 % for citrate and NaCl solutions, respectively. CONCLUSION: the studied herbal extracts were efficient for dissolving cystine stones, probably resulting from the formation of complexes between cystine and polyhydroxylated molecules present in the extracts. These results, to be confirmed in vivo, underline the potential interest of the plant extracts to treat cystine stones.

[Revisiting the chemical diversity in prostatic calculi: a SEM and FT-IR investigation]. / Diversité chimique des calculs prostatiques : une investigation par MEB et spectroscopie infrarouge.

OBJECTIVE: Revisiting the chemical diversity of the crystalline phases of prostatic calculi by means of SEM and FT-IR analysis. METHODS: A set of 32 prostatic calculi has been studied by FT-IR and SEM. RESULTS: FT-IR analysis has determined the chemical composition of each prostatic calculus and the SEM observation has described the morphology of the calculi surfaces and layers. Infrared analysis revealed that 90.7% of the stones were mainly composed of calcium phosphates. However, several mineral phases previously not reported in prostatic calculi were observed, as brushite or octocalcium phosphate pentahydrate. CONCLUSION: Prostatic calculi exhibited a diversity of crystalline composition and morphology. As previously reported for urinary calculi, relationships between composition and morphology of prostatic stones and étiopathogenic conditions could be of interest in clinical practice.

[Simultaneous bilateral percutaneous nephrolithotomy: Series of 60 cases]. / Néphrolithotomie percutanée bilatérale en un temps: série de 60 cas.

OBJECTIVE: Retrospective evaluation of the efficacy and morbidity of simultaneous bilateral percutaneous nephrolithotomy (SB-PCNL). METHODS: From January 1993 to July 2009, 60 patients have undergone SB-PCNL over a series of 1709 PCNL. Thirty men and 30 women, mean age 45 years old (13-78), were treated for bilateral renal stones (120 kidneys) of 1177 mm(2) (268-4972 mm(2)); 25 were complete staghorn stones. RESULTS: Operating time for the first side of PCNL was 80 min (30-270) and 45 min (10-90) for the opposite side. Overall OR occupation was 188 min (90-360). Forty-five patients were stone free after one session; 15 patients (25%) have a complementary treatment to be stone free: five PCNL (one bilateral); eight ESWL (four with JJ stent) and two flexible ureteroscopy. No blood transfusion was required. Renal function was unchanged at 1 month. Clavien grade for complications were as follows: two grade IIIb, one grade IVa and one grade IVb. Hospitalization stay was 4±4.9 days (2-35) taking account of two major sepsis (one pulmonary and one septicemia). CONCLUSION: SB-PCNL was well tolerated with comparable morbidity and efficacy to PCNL performed on each side in two separate sessions. Nevertheless, SB-PCNL has to be performed for selected patients in expert centers.

Racemic calcium tartrate tetrahydrate [form (II)] in rat urinary stones.

The title compound, [Ca(C4H4O6)].4H2O, calcium tartrate tetrahydrate, is a new triclinic centrosymmetric form identified in rat kidney calculus. The crystal structure was determined from powder and single-crystal X-ray diffraction. The four water molecules belong to one square face of the Ca-atom coordination (a square antiprism), the four O atoms of the second square face coming from two tartrate anions, building infinite chains alternating Ca atom polyhedra and tartrate anions along a, with the chains cross-linked by a network of hydrogen bonds.