2022 Recommendations of the AFU Lithiasis Committee: Specific cases - chronic kidney disease, bilateral stones, and solitary kidney

Chronic kidney disease, diabetes and hypertension are risk factors of kidney function impairment. The relative risk of kidney failure is 1.52 in patients with urinary stone disease. The various techniques used to remove upper urinary tract stones generally do not alter kidney function in patients with normal kidney function and may sometimes improve kidney function or slow its deterioration in patients with kidney disease. Compared to the asynchronous treatment of bilateral renal and ureteral stones, concomitant treatment is associated with higher risk of anuria and the need of additional interventions, in the absence of postoperative stenting. For the treatment of solitary kidney stones, the absence of postoperative stenting increases the risk of postoperative anuria. Moreover, the multiplication of percutaneous nephrolithotomy access tracts increases the risk of bleeding and that of kidney function impairment. METHODOLOGY: These recommendations were developed according to two methods: the Clinical Practice Recommendations (CPR) method and the ADAPTE method, depending on whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis) [EAU Guidelines on urolithiasis. 2022] and their adaptability to the French context.

Renal function change after radical cystectomy for urothelial carcinoma patients with a solitary kidney may be independent of urinary diversion type

PURPOSE

To compare renal function change by urinary diversion (UD) type (ileal conduit [IC] vs. neobladder [NB]) in patients with a single kidney who underwent radical cystectomy (RC) due to bladder cancer.

MATERIALS AND METHODS

We evaluated the renal function change in 86 patients with a single kidney who underwent RC between January 1999 and August 2022. Renal function was assessed using serum creatinine, serum estimated glomerular filtration rate (eGFR), eGFR difference value (preoperative and follow-up values), and eGFR difference proportion (eGFR difference value/preoperative eGFR) at 1, 3, 6, 12, 24, 36, 48, and 60 months. In addition, multiple definitions of eGFR decline were evaluated: 10 points, 10%, and 20% decline in eGFR. Cox regression models were used to identify risk factors of eGFR decline-free, recurrence-free, overall, and cancer-specific survival rates.

RESULTS

A total of 54 patients (62.8%) underwent IC, whereas 32 (37.2%) underwent NB. Baseline characteristics were similar between the two groups except for age and body mass index. Renal functions over time by various methods did not differ significantly between the IC and NB groups. Furthermore, eGFR decline-free survival rate using different definitions was similar between the IC and NB groups. Overall survival, recurrence-free survival, and cancer-specific-free survival rates were not different between the IC and NB groups.

CONCLUSIONS

UD type (IC vs. NB) did not impact the renal function change of patients with a single kidney who underwent RC. Therefore, patients with a single kidney might be considered to be an indication of NB.

Optimal Renal Artery-Aorta Angulation Revealed by Flow Simulation

INTRODUCTION

In the circulatory system, the vessel branching angle may have hemodynamic consequences. We hypothesized that there is a hemodynamically optimal range for the renal artery's branching angle.

METHODS

Data on the posttransplant kinetics of estimated glomerular filtration rate (eGFR) were analyzed according to the donor and implant sides (right-to-right and left-to-right position; n = 46). The renal artery branching angle from the aorta of a randomly selected population was measured using an X-ray angiogram (n = 44). Computational fluid dynamics simulation was used to elucidate the hemodynamic effects of angulation.

RESULTS AND DISCUSSION

Renal transplant patients receiving a right donor kidney to the right side showed faster adaptation and higher eGFR values than those receiving a left donor kidney to the right side (eGFR: 65 ± 7 vs. 56 ± 6 mL/min/1.73 m2; p < 0.01). The average branching angle on the left side was 78° and that on the right side was 66°. Simulation results showed that the pressure, volume flow, and velocity were relatively constant between 58° and 88°, indicating that this range is optimal for the kidneys. The turbulent kinetic energy does not change significantly between 58° and 78°.

CONCLUSION

The results suggest that there is an optimal range for the renal artery's branching angle from the aorta where hemodynamic vulnerability caused by the degree of angulation is the lowest, which should be considered during kidney transplantations.

Partial nephrectomy in solitary kidneys: comparison between open surgery and robotic-assisted laparoscopy on perioperative and functional outcomes (UroCCR-54 study)

PURPOSE

The management of solitary kidney tumors is a surgical challenge, requiring irreproachable results on both oncological and functional outcomes. The goal of our study was to compare the perioperative results of robotic-assisted partial nephrectomy (RAPN) to open surgery in this indication.

METHODS

We led a multicentric study based on the prospectively maintained French national database UroCCR. Patients who underwent partial nephrectomy on a solitary kidney between 1988 and 2020 were included. Clinical and pathological data were retrospectively analyzed. The main outcome of the study was the analysis of the variation of the estimated glomerular filtration rate (eGFR) calculated according to MDRD at 3, 6, 12, and 24 months depending on the chosen surgical approach. The secondary outcomes were the comparison of Trifecta success, perioperative complications, and length of hospital stay.

RESULTS

In total, 150 patients were included; 68 (45%) in the RAPN group and 82 (55%) in the open surgery group. The two groups were comparable for all data. The variation of eGFR at 3, 6, 12, or 24 months was comparable without any significant difference between the 2 groups (p = 0.45). Trifecta was achieved in 40% of the patients in the RAPN group and 33% in the open group (p = 0.42). A significant difference was observed for the length of stay, 5 days for the robot group versus 9 days for the open surgery group (p < 0.0001).

CONCLUSION

In our study, the surgical approach did not modify functional results and we noted a significant decrease in hospital stay and complications in the RAPN group. RAPN is a safe and efficient method for management of kidney tumors in solitary kidneys.

Radical cystectomy and urinary diversion outcomes in patients with single vs. double renal unit: A 2:1 matched-pair analysis

OBJECTIVE

To evaluate perioperative and functional outcomes of radical cystectomy (RC) and urinary diversion (UD) in patients with a single kidney (SK) vs. double kidneys (DK).

METHODS

We reviewed records of patients who underwent RC for bladder cancer with a history of prior or concurrent nephrectomy at USC between 2004 and 2020. Patients with chronic kidney disease who were already on dialysis were excluded. UD, perioperative complications, and postoperative glomerular filtration rate (GFR) of the SK group were compared with a group of patients who underwent RC with DK using 2:1 matching with respect to age, sex, preop GFR, and tumor stage.

RESULTS

We included 186 patients (SK = 62 and DK = 124). Half of the SK patients underwent continent UD. SK patients had a higher length of hospital stay compared to the DK group; however, 90-day complications, readmission, and mortality rates were similar. In patients with continent diversion, SK vs. DK showed similar 90-day complications (71% vs. 69%, P = 1.0). SK patients had significantly lower GFRs at discharge, 3-, and 12-month following RC compared to the DK group. Postoperative GFRs of the SK patients with continent vs. incontinent UD were statistically similar. On multivariable analysis, UD (i.e. continent vs. incontinent) was not associated with post-op GFR decline at discharge, 3- and 12-month following RC.

CONCLUSIONS

Perioperative outcomes of radical cystectomy patients with single kidney are similar to double kidney patients, except for more GFR decline in single kidney cases. Continent urinary diversion in single kidney is as safe as double kidney patients.

Is the prognosis of congenital single functioning kidney benign? A population-based study

BACKGROUND

We investigated the risk of kidney injury among adolescents with and without a congenital single functioning kidney (SFK).

METHODS

This retrospective study is based on a medical evaluation database of 17-year-old Israeli conscripts, born during 1989-1999. Those with congenital SFK diagnosis, verified by a pediatric nephrologist's review of the original military medical committee classifications, were compared to the rest of the cohort. Kidney injury (KI) was defined as proteinuria, high blood pressure (BP), or estimated glomerular filtration rate (eGFR) < 90 ml/min/1.73 m² prior to army recruitment. Risk factors for KI were examined using logistic regression.

RESULTS

Of 979,630 screened candidates, 353 were diagnosed with SFK. The yearly incidence of SFK gradually increased in the first years of the study, reaching a plateau in 1995 (5.5 ± 1.2/10,000 births/year). The male to female ratio was 2.7:1. Concomitant genital malformations were documented in 5.5% of those with SFK. KI was more prevalent in the SFK than the control group (42.2% vs. 23.5%, p < 0.001). All three components of KI were more common in the SFK than the control group: high BP (31.7% vs. 23.1%, p < 0.001), proteinuria (18.2% vs. 0.4%, p < 0.001), and eGFR <90 ml/min/1.73m² (12.0% vs 0.1%, p < 0.001). Multivariate analysis of the SFK group revealed associations of higher mean BMI, male sex, and smaller ultrasonographic kidney length with KI.

CONCLUSIONS

This large population-based study documents a significant risk for KI among adolescents with SFK. Obesity represents a major modifiable risk factor for KI, implicating the need for closer follow-up in this group during childhood.

Emphysematous pyelonephritis on a single anatomic kidney: About a case report and literature analysis

Emphysematous pyelonephritis (EPN) on a single kidney is an extremely uncommon necrosing infection of renal parenchyma due often to infection by a gas-producing bacteria in a patient with uncontrolled diabetes mellitus. The management associate aggressive fluid and electrolyte resuscitation with several dialysis sessions, control of blood sugar levels, and broad-spectrum antibiotics with an urgent drainage. This paper aims to describe a case of a 68-year-old diabetic male patient who presented with EPN on a single kidney managed by conservative treatment.

Chimney Technique with Nellix EndoVascular Aneurysm Sealing System in a Patient with Single Kidney and Juxtarenal Abdominal Aortic Aneurysm

We present a saccular asymptomatic juxtarenal abdominal aortic aneurysm in a 70-year-old male with a very short left renal artery supplying the only kidney. The case was successfully treated with the Nellix EndoVascular Aneurysm Sealing system combined with a chimney technique.