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.

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.

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.

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 (AU)

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 (AU)

Practical Mathematical Model for the Evaluation of Main Parameters in Polymer Flooding: Rheology, Adsorption, Permeability Reduction, and Effective Salinity.

Polymer flooding is one of the most used chemical enhanced oil recovery (CEOR) technologies worldwide. Because of its commercial success at the field scale, there has been an increasing interest to expand its applicability to more unfavorable mobility ratio conditions, such as more viscous oil. Therefore, an important requirement of success is to find a set of design parameters that balance material requirements and petroleum recovery benefits in a cost-effective manner. Then, prediction of oil recovery turns out to handle more detailed information and time-consuming field reservoir simulation. Thus, for an effective enhanced oil recovery project management, a quick and feasible tool is needed to identify projects for polymer flooding applications, without giving up key physical and chemical phenomena related to the recovery process and avoiding activities or projects that have no hope of achieving adequate profitability. A detailed one-dimensional mathematical model for multiphase compositional polymer flooding is presented. The mathematical formulation is based on fractional flow theory, and as a function of fluid saturation and chemical compositions, it considers phenomena such as rheology behavior (shear thinning and shear thickening), salinity variations, permeability reduction, and polymer adsorption. Moreover, by setting proper boundary and initial conditions, the formulation can model different polymer injection strategies such as slug or continuous injection. A numerical model based on finite-difference formulation with a fully implicit scheme was derived to solve the system of nonlinear equations. The validation of the numerical algorithm is verified through analytical solutions, coreflood laboratory experiments, and a CMG-STARS numerical model for waterflooding and polymer flooding. In this work, key aspects to be considered for optimum strategies that would help increase polymer flooding effectiveness are also investigated. For that purpose, the simulation tool developed is used to analyze the effects of polymer and salinity concentrations, the dependence of apparent aqueous viscosity on the shear rate, permeability reduction, reversible-irreversible polymer adsorption, polymer injection strategies on petroleum recovery, and the flow dynamics along porous media. The practical tool and analysis help connect math with physics, facilitating the upscaling from laboratory observations to field application with a better-fitted numerical simulation model, that contributes to determine favorable scenarios, and thus, it could assist engineers to understand how key parameters affect oil recovery without performing time-consuming CEOR simulations.

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.

Multiple renal tumorectomy in a Von Hipple Lindau patient. Combined retro/transperitoneal approach with intracorporeal hypotermia

ABSTRACT Objective & Introduction: To show the feasibility of a combined transperitoneal (TP) and retroperitoneal (RP) laparoscopic approach in a Von Hipple-Lindau (VHL) patient with multiple kidney tumors. VHL is an autosomal dominant inherited syndrome characterized by a high incidence of benign and malignant tumors and cysts in many organs. Renal cell carcinoma is one of the most common and a leading cause of mortality (1). Surgical approach is usually complex because of its multiplicity and the need of maximum kidney function preservation due to the risk of future recurrences (2, 3). Intracorporeal renal hypothermia may be useful in these cases to prevent permanent renal function loss (4). Materials and Methods: A 40 years old male was being monitored for multiple bilateral renal masses. Family history included a VHL syndrome affecting his mother and sister. Past medical history included a VHL syndrome with multiple cerebellar and medular hemangioblastomas, a pancreatic cystoadenoma and bilateral kidney tumors which had significantly grown up during follow-up. The patient was scheduled for laparoscopic multiple partial nephrectomy. A combined TP and RP approach with intracorporeal hypothermia was chosen. Results: A total of six right kidney tumors were removed. Operative time was 240 min. Cold ischemia time was 50 min. Average kidney temperature was 23.7°C. Blood losses were negligible. The patient was discharged after 72 hours. No major changes in serum creatinine were found during the follow-up. Final pathology revealed a clear cell renal cell carcinoma, pT1a, ISUP grade 2 in most of the tumors but one ISUP grade 3. Surgical margins were negative. Conclusions: Combined TP and RP is a feasible alternative for the treatment of multiple renal tumors. It's safe and effective, allowing the use of intracorporeal hypothermia which may improve postoperative renal function. Consistent experience is needed before embarking on this surgery.

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

ABSTRACT

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).

[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.

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

OBJETIVOS: Presentar nuestra experiencia en cirugía intrarrenal retrógrada (RIRS) bilateral en un mismo acto quirúrgico, analizando la tasa de pacientes libres de litiasis (SFR), el tiempo quirúrgico, la estancia hospitalaria, las complicaciones, las diferencias entre la creatinina pre- y postoperatoria y la composición de los cálculos. MÉTODOS: Entre abril de 2012 y febrero de 2016 se han realizado 24 RIRS en 12 pacientes con litiasis renal bilateral, entre los que se encuentran 9 hombres y 3 mujeres, con mediana de edad de 47,5 (rango: 55), IMC: 23.59 (rango: 12,5). RESULTADOS: El número de cálculos por unidad renal es de 2,7 (rango: 12), localizados preferentemente en la pelvis renal (40%), con un tamaño medio de 16,08±8,06 mm y una carga litiásica media de 258,54±242,59 mm2. El SFR a los 3 meses es de 83,33%. El tiempo operatorio medio ha sido 75 minutos y la estancia hospitalaria mediana de 2 días. Se han registrado 3 complicaciones (25%), todas ellas complicaciones menores (Clavien I-II). No se han registrado complicaciones mayores (Clavien III-V). CONCLUSIONES: La RIRS bilateral en un mismo acto quirúrgico es una herramienta eficaz y segura para el tratamiento de pacientes con litiasis renales bilaterales

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