Prevalence of distal renal tubular acidosis in patients with calcium phosphate stones.

INTRODUCTION AND PURPOSE: Distal renal tubular acidosis (DRTA) is a metabolic disorder that associates urolithiasis and urinary pH > 6. The prevalence of DRTA in patients with calcium phosphate stones is not well known. The objective is to determine the prevalence of DRTA in patients with calcium phosphate stones and urinary pH above 6 based on the furosemide test. METHODS: A total of 54 patients with calcium phosphate stones and urinary pH above 6.0 were submitted to the furosemide test. The association of DRTA with age, sex, type of stone, stone recurrence, stone bilaterality, 24-h urine biochemistry, and adverse effects of the furosemide test were examined. RESULTS: The furosemide test indicated that 19 of 54 patients (35.2%) had DRTA. The sex ratio was similar in the two groups (p < 0.776). The DRTA group was significantly younger (p < 0.001), and had a higher prevalence of bilateral stones (p < 0.001), a higher prevalence of recurrent stones (p < 0.04), a lower plasma potassium level (p < 0.001), a higher urinary Ca level (p ≤ 0.05), and a lower urinary citrate level (p < 0.001). None of the patients reported adverse effects from the furosemide test. CONCLUSIONS: There was a high prevalence of DTRA in patients with urinary pH above 6 and calcium phosphate stones. Young age, bilateral stones, stone recurrence, hypercalciuria, hypocitraturia, and plasma hypokalemia were associated with DRTA. None of the patients reported adverse effects of the furosemide test.

Intracorporeal renal hypothermia with ice slush for robot-assisted partial nephrectomy in a highly complex renal mass.

OBJECTIVE: To report our step-by-step technique for robotic partial nephrectomy using intracorporeal renal hypothermia (RPNIRH) in a highly complex renal mass. The robotic technology has allowed surgeons to recreate the principles of open surgery in a minimally invasive approach (1). With increasing experience, larger deeply infiltrative tumors can be treated with this technique (2). In complex cases, when a long warm ischemia time is expected, intracorporeal renal hypothermia can be useful to prevent permanent renal function loss (3).

Diet in Different Calcium Oxalate Kidney Stones.

Diet can be a helpful tool to enhance the quality of urine and lower the likelihood and recurrence of kidney stones. This study set out to identify the foods and nutrients that are associated with each type of calcium oxalate kidney stone formation. A single-center, cross-sectional study was conducted. Between 2018 and 2021, a sample of 90 cases (13 cases with papillary COM, 27 with non-papillary COM, and 50 with COD kidney stones), as well as a control group of 50 people, were chosen. A food intake frequency questionnaire was completed by the study's participants, and the results were compared between groups. Additionally, a comparison of the 24 h urine analysis between stone groups was made. Processed food and meat derivatives were linked to COM papillary calculi (OR = 1.051, p = 0.032 and OR = 1.013, p = 0.012, respectively). Consuming enough calcium may offer protection against non-papillary COM stones (OR = 0.997; p = 0.002). Similarly, dairy product consumption was linked to COD calculi (OR = 1.005, p = 0.001). In conclusion, a diet high in animal items may increase the risk of developing papillary COM stones. Consuming calcium may be preventive against non-papillary COM calculi, and dairy product consumption may be a risk factor for COD stones.

Relationship between Urinary Parameters and Double-J Stent Encrustation.

(1) Background: This study aimed to determine the relationship between metabolic urine conditions and the formation, severity, and composition of encrustations in ureteral stents. (2) Methods: Ninety stone-former patients requiring a double-J stent were prospectively enrolled. We collected 24 h metabolic urine samples and demographic data, including indwelling time and previous stone composition. The total deposit weight was obtained, and a macroscopic classification according to the degree of encrustation (null, low, moderate, and high) was created, allowing for intergroup comparisons. Stereoscopic and scanning electron microscopy were performed to identify the type of embedded deposits (calcium oxalate, uric acid, and infectious and non-infectious phosphates). (3) Results: In total, 70% of stents were encrusted; thereof, 42% had a moderate degree of encrustation. The most common encrustation type was calcium oxalate, but infectious phosphates were predominant in the high-encrustation group (p < 0.05). A direct correlation was observed between the purpose-built macroscopic classification and the encrustation weights (p < 0.001). Greater calciuria, uricosuria, indwelling time, and decreased diuresis were observed in stents with a higher degree of encrustation (p < 0.05). The urinary pH values were lower in patients with uric acid encrustations and higher in those with infectious phosphate encrustations (p < 0.05). When compared to non-encrusted stents, patients with calcium-oxalate-encrusted stent showed greater calciuria, phosphaturia, indwelling time, and reduced diuresis; patients with uric-acid-encrusted stent showed greater uricosuria; and patients with infectious and non-infectious phosphate encrustation showed greater urinary pH (p < 0.05). (4) Conclusions: Metabolic urine conditions play a critical role in the formation, composition, and severity of double-J stent encrustation.

Effects of short and long-term indapamide treatments on urinary calcium excretion in patients with calcium oxalate dihydrate urinary stone disease: a pilot study.

OBJECTIVE: The aim of this study was to determine the relative calcium-reducing effects of indapamide at 6 and 18 months using a dose of 1.5 mg/day. MATERIAL AND METHODS: Twenty-two patients with idiopathic hypercalciuria and calcium oxalate dihydrate urinary stone disease (minimum one stone episode) were selected. Each patient began a therapy regime of 1.5 mg indapamide sustained release taken once a day in the evening. Under basal conditions and after 6 and 18 months of treatment, subjects submitted urine and blood samples for analysis. The primary aim of this study was to assess the effects on excretion and concentration of calcium in urine. RESULTS: For 2 h urine, there was a mean decrease in urinary calcium concentration of 47%, whereas urinary calcium concentrations decreased by 53% in 24 h urine (p < 0.05) at 6 months of treatment. Blood urate levels rose by 19% (p < 0.05). Treatment for 18 months resulted in significant reduction in urinary calcium levels, by approximately 48% (p < 0.05) in both 2 h and 24 h urine. A 21% increase in urate levels in the blood was observed (p < 0.05). The remaining parameters remained unaltered. CONCLUSIONS: Owing to the low effective dosage of indapamide (1.5 mg/day) and the lack of any severe side-effects, this drug would appear to be a good candidate for use in the control of hypercalciuria. As such, it could prove efficacious in the prevention of recurrent kidney stones that are often associated with this condition.

A prioritization score for elective urological surgery during the COVID-19 pandemic: The Medically Necessary Time-Sensitive (MeNTS) score system.

PURPOSE: The COVID19 pandemic has caused a redistribution of hospital resources. Prioritization strategies are needed in order to organize elective surgeries. We compared the new Medically Necessary Time-Sensitive score (MeNTS) and its factors (disease, procedure, and patient factors) between operated and deferred cases, and also to a subjective priority scale in the Urology department. METHODS: The MeNTS score and a subjective prioritization scale were prospective applied to all patients included on the surgical waiting list from March 10 to September 9, 2020. Mann-Whitney U test was used to compare MeNTS scores between operated and non-operated groups. Kruskal-Wallis test was used to compare MeNTS scores between three subjective priority groups. RESULTS: A total of 150 cases were operated while 100 were deferred. Median total MeNTS score in the operated group was 39.5 whereas in the non-operated group it was 38 (p = 0.135). Median disease factors score was 9.5 in the operated group and 11 in the non-operated group(p = 0.033). Median procedure factors score was 10 in both groups (p = 0.02). Median patient factors score was 17 in the operated group and 18 in the non-operated group (p = 0.210). Disease factors displayed a significant difference between the three subjective priority groups. CONCLUSIONS: Total MeNTS score does not show significant differences between operated and non-operated patients. However, we demonstrate a relationship between MeNTS disease factors and the operated group as well as with the subjective priority scale.

Effect of phytate on hypercalciuria secondary to bone resorption in patients with urinary stones: pilot study.

The objective is to evaluate the effect of phytate supplements on calciuria in patients with urinary stones and elevated bone resorption. The secondary objective is to analyze the therapeutic effect of phytate based on measurements of serum markers of bone resorption. This is a controlled randomized study included patients according to predefined inclusion and exclusion criteria, and randomized them into two groups. Patients in the phytate group received a 380 mg capsule of calcium-magnesium InsP6 (Salvat Laboratories®) every 24 h for 3 months and patients in the control group received no treatment. All included patients were male or female, 18-65 years old, had hypercalciuria (> 250 mg/24 h), had a ß-Crosslaps level greater than 0.4 ng/mL, and had bone densitometry results indicative of osteopenia or osteoporosis in the femur and/or spine. At study onset, calciuria was 321 ± 52 mg/24 h in the phytate group and 305 ± 57 mg/24 h in the control group (p > 0.05). At 3 months, calciuria was significantly lower in the phytate group than the control group (226 ± 45 mg/24 h vs. 304 ± 58 mg/24 h, p < 0.05). At study onset, the mean ß-CrossLaps level was 1.25 ± 0.72 ng/mL in the phytate group and 0.57 ± 0.13 ng/mL in the control group (p < 0.05). However, at 3 months, the ß-CrossLaps level was significantly lower in the phytate group than in the control group (0.57 ± 0.13 ng/mL vs. 0.77 ± 0.42 ng/mL, p < 0.05). Phytate reduced calciuria in patients with hypercalciuria secondary to bone resorption. The ß-CrossLaps assay was effective for evaluating the efficacy of phytate on hypercalciuria during follow-up.

Effect of Ischemia Times and Donor and Recipient Features on Maastricht Category III Kidney Transplant Outcomes.

OBJECTIVE: Expansion of the donor pool has been enabled by the use of donation after circulatory death (DCD). The aim of this study is to identify what donation features are able to predict kidney transplant (KT) outcomes from DCD. MATERIALS AND METHODS: A prospective analysis of all DCD KT from June 2016 to November 2019 was conducted. Association between donor and recipient features, and ischemia times with delayed graft function (DGF) and serum creatinine (Cr) at discharge, and at three and twelve months were analysed. RESULTS: A total of 86 KT were performed. The results revealed a relationship between donor age (p = 0.014) and receptors on haemodialysis (p = 0.001) with DGF. There was no association between different ischemia times and DGF. Residual urine output greater than 500mL/day and being on peritoneal dialysis were found to be protective factors for DGF. Correlation analysis illustrated a significant correlation between donor age and Cr at discharge and at 3 months. CONCLUSION: Higher donor age and being on haemodialysis were risk factors for DGF. Likewise, donor age did not show a significant association with 12-month serum Cr. These results demonstrate that donor age is a risk factor for DGF but does not affect long term graft function.

What Donation Features are Related to Complications in Donation after Circulatory Death Kidney Transplant? Analysis of Risk Factors for Complication after Circulatory Death Kidney Transplant.

OBJECTIVE: Complications in donation after circulatory death (DCD) kidney transplants (KT) are barely described, while in some urological complications the cause is unknown. The aim of this study is to describe surgical and urological complications and analyze what donation features could be involved. METHODS: A prospective, single center study was performed from 2016 to 2019 including all KT from controlled cardiac death donors (cDCD). RESULTS: A total of 86 cDCD KT were included in the study. Recipient BMI, residual urine output (RUO) <500 mL/day, delayed graft function (DGF), and wound complication were related to UTI (p = 0.020, p = 0.008, p = 0.016, and p = 0.004, respectively). Features related to early graft nephrectomy were recipient BMI and recipients with diabetes mellitus (DM) (p = 0.025 and p = 0.036, respectively). DM in recipients was significantly associated with hematuria (p = 0.046). Urinary leak (UL) was associated to vascular complication and ureteral stricture (US) (p = 0.029 both). UL and lymphocele were associated to US (p = 0.029 both). Features related to lymphocele were recipient BMI and US (p = 0.028 and p = 0.029, respectively). History of previous transplant, time from cardiac arrest (CA) to cold flush, and DGF, were associated to wound complication (p = 0.040, p = 0.011 and p = 0.016, respectively). CONCLUSIONS: Surgical and urological complications after KT are an important issue to resolve. Our data revealed an association between RUO <500 mL/day, DGF, and wound complication with urinary infection, as well as between recipient DM and hematuria. Recipient BMI and DM were related to early graft nephrectomy. Vascular complications were associated with urinary leak, and lymphocele with US. Finally, wound complication was related to previous transplant, DGF, and time from CA to cold flush. This data revealed interesting associations between donor and recipient features and cDCD KT complications, providing more information to improve prevention and management.

Non-infectious phosphate renal calculi: fine structure, chemical and phase composition.

BACKGROUND: Chemical composition of internally non-homogeneous phosphate stones should be related to the conditions prevailing during the formation of each individual part. OBJECTIVE: The object of this paper was to provide a detailed study of phosphate stone composition on the micro- and macro-scales. METHODS: Fine inner structure, chemical and phase composition of 10 phosphate calculi from different patients were determined by chemical (wet) analysis, observation by scanning microscope, semi-quantitative determination of Ca, Mg, P and C by energy dispersive X-ray and by X-ray diffraction. Results. Eight calculi are formed by amorphous calcium phosphate and two by hydroxyapatite. Magnesium was inversely related to Ca/P ratio. Point chemical composition of solid phase varies in wide limits, i.e. composition of calculus interior is highly inhomogeneous on the microscale. All studied calculi contained an abundance of organic matter incorporated in their volume; the content of carbon was double the calcium content in molar quantities. CONCLUSIONS: Phosphate renal calculi with the low Ca/P molar ratio predominantly consist of amorphous calcium phosphate whereas those with a high Ca/P molar ratio are composed of poorly crystalline hydroxyapatite which can be partially carbonated. Magnesium may be an inhibitor of HAP formation from urine. Abundant organic matter incorporated into the calculus volume indicates its decisive role at stone formation. Variable point composition of stones implies widely varying conditions during their development.

Concomitant carcinoma in situ and tumour size are prognostic factors for bladder recurrence after nephroureterectomy for upper tract transitional cell carcinoma.

OBJECTIVE: To identify prognostic risk factors for the development of subsequent bladder recurrence in patients undergoing nephroureterectomy (NU) for upper tract transitional cell carcinoma (TCC). PATIENTS AND METHODS: The data of 79 patients who underwent NU for localized upper tract TCC were collected retrospectively, and analysed for clinical and pathological variables. Patients with previous invasive bladder tumours were excluded. Age, sex, tumour location, previous/synchronic bladder tumours, stage, grade, concomitant upper tract carcinoma in situ (CIS), and size were all analysed. Univariate and multivariate analyses were done using the Kaplan-Meier Method, with the log-rank test, and the Cox proportional hazards regression model, respectively. RESULTS: The median follow-up was 71 months, during which bladder tumours were detected in 42 patients (54%). On univariate analyses, tumour stage ≥ pT2 (P = 0.015), concomitant upper tract CIS (P = 0.001), high-grade tumour G3 (P = 0.027) and tumour size > 4 cm (P = 0.011) were statistically significant predictors of intravesical recurrence. After multivariate analyses, concomitant CIS (P = 0.005, hazard ratio 2.9, 95% confidence interval 1.4-5.8) and tumour size > 4 cm (P = 0.042; 1.9, 1-3.7) were significantly related to bladder tumour recurrence. CONCLUSION: There is a high bladder recurrence rate after NU for upper tract TCC. Patients with tumours of > 4 cm and concomitant upper tract CIS have a major risk of developing subsequent bladder recurrence. Therefore, closer surveillance of the bladder is needed in these patients and they may potentially benefit from prophylactic intravesical instillation therapy.

Robotic Partial Nephrectomy for Complex Hilar Tumors: Step by step.

OBJECTIVE: To report our step-by-step technique and provide tips and tricks for robotic partial nephrectomy (RPN) in a highly complex renal mass. Robotic surgery has widened the indications of the conservative treatment for renal masses. With increasing experience, larger deeply infiltrative tumors, or tumors involving the renal hilum can be treated with robotic partial nephrectomy. MATERIALS AND METHODS: A 78-year-old male came to our attention for a complex right renal mass. Past medical history included severe hypertension and a myocardial infarction with subsequent stent placement in 2014. Baseline renal function assessed by serum creatinine was 0.93 mg/dl. The preoperative computed tomography scan and magnetic resonance showed a right enhancing posterior renal mass, 7.6 cm in diameter, cT2a, and RENAL score 12. The patient was scheduled for robotic partial nephrectomy. Transperitoneal approach with three arms robotic configuration was chosen. RESULTS: Operative time including robot's docking was 195 minutes. Warm ischemia time was 19 minutes. Blood losses were negligible, with no transfusions required. Serum creatinine at discharge was 1.15 mg/dl. Final pathology revealed a clear cell renal cell carcinoma, pT3b, and ISUP grade 3, involving the sinus fat and the renal vein. Surgical margins were negative. CONCLUSION: Robotic partial nephrectomy can be successfully performed in cases of completely endophytic central, hilar masses. Consistent experience is needed before embarking on this surgery. Future studies are needed to determine the long-term outcomes for partial nephrectomy for these complex tumors.

Papillary and nonpapillary calcium oxalate monohydrate renal calculi: comparative study of etiologic factors.

Calcium oxalate monohydrate (COM) renal calculi can be classified into two groups: papillary and nonpapillary. In this paper, a comparative study between etiologic factors of COM papillary and nonpapillary calculi is performed. The study included 40 patients with COM renal calculi. The urine of these individuals was analyzed. Case history, lifestyle, and dietetic habits were obtained. No significant differences between urinary biochemical data of both groups were observed; 50% of COM papillary stone formers and 40% of COM nonpapillary stone formers had urolithiasis family history. A low consumption of phytate-rich products was observed for both groups. A relationship between profession with occupational exposure to cytotoxic products and COM papillary renal lithiasis was detected. The results suggest that COM papillary calculi would be associated to papillary epithelium alterations together with a crystallization inhibitors deficit, whereas COM nonpapillary calculi would be associated to the presence of heterogeneous nucleants and a crystallization inhibitors deficit.

[Efficacy and safety of bilateral RIRS for renal lithiasis.] / Eficacia y seguridad de la RIRS bilateral para el tratamiento de litiasis renal.

OBJECTIVES: We present our experience in single-stage bilateral retrograde intrarenal surgery (RIRS), analyzing the stone free rate (SFR), surgical time, hospital stay, pre- and post procedure creatinine, stone composition and complications. METHODS: Between April 2012 and February 2016, 24 RIRS were carried out in 12 patients with bilateral renal stones. Patients were 9 men and 3 women with a median age of 47.5 (range:55),IMC: 23.59 (range: 12.5). RESULTS: Mean number of stones per renal unit was 2.7 (range: 12), mostly located in the renal pelvis (40%), with an average size of 16.08±8.06 mm and an average stone burden of 258.54±242.59 mm². The SFR at 3 months was 83.33%. Average operation time was 75 minutes and median hospital stay was 2 days. Three complications were recorded (25%), all of them minor (Clavien I-II). No major complications were recorded (Clavien III-V). CONCLUSIONS: Single-stage bilateral RIRS is a safe and effective tool for the treatment of patients with bilateral renal stones.

On the origin of calcium oxalate monohydrate papillary renal stones.

Calcium oxalate monohydrate (COM) papillary calculi can be initiated by subepithelial calcification of the renal papillae. Hydroxyapatite disruption of the papillary epithelial layer can become the nidus of a COM papillary calculus. This study evaluated the causes of papillary tissue calcifications in 60 patients with calcium oxalate lithiasis, 30 with COM papillary and 30 with calcium oxalate dihydrate (COD) calculi. Urinary redox potential was higher in the COM than the COD group, suggesting that the former is more deficient in antioxidants due to increased oxidative stress. Urinary calcium was significantly higher in the COD group, whereas urinary oxalate was significantly higher in the COM group, suggesting a greater degree of oxidative injury of renal cells. Evaluations of their diets showed that both groups consumed low amounts of phytate-rich products. Of chronic diseases possibly associated with urolithiasis, only the prevalence of gastroduodenal ulcer differed significantly, being higher in the COM group and suggesting that epithelial lesions are common to gastroduodenal ulcers and COM papillary renal stones. Occupational exposure to cytotoxic products occurred in 47 % of the COM and 27 % of the COD group, but this difference was not statistically significant. These findings indicate that oxidative stress is associated with injury to papillary tissue and that this is the origin of intrapapillary calcifications. The continuation of this process is due to modulators and/or deficiencies in inhibitors of crystallization. Identifying and eliminating the causes of injury may prevent recurrent episodes in patients with papillary COM calculi.