OBJECTIVE: In the modern era of robotic renal procedures and diagnostics, an even more detailed anatomical understanding than hitherto is necessary. Valves of the renal veins (RVV) have been underemphasized and have been disputed by some authors, and few textbooks describe them. The current anatomical study was performed to address such shortcomings in the literature.
METHODS: One hundred renal veins were studied in fifty adult formalin-fixed cadavers. Renal veins were removed from the abdomen after sectioning them flush with their entrance to the renal hilum. The inferior vena cava was then incised longitudinally and opened, and RVV were examined grossly and histologically. A classification scheme was developed and applied to our findings.
RESULTS: Nineteen RVVs were observed in the fifty cadavers (38%). Four (8%) valves were found on right sides and fifteen (30%) on left sides. The valves were seen as cord/band-like, folds, and single and double leaflets. Histologically, they were all extensions of the tunica intima.
CONCLUSIONS: On the basis of our study, RVV are not uncommon. They were more common on left sides, and on both sides, they were found within approximately one centimeter of the junction of the inferior vena cava and renal vein. Although the function of such valves cannot be inferred from this anatomical study, the structures of the Single leaflet valve (TS2) and Double leaflet valve (TS3) valves suggest they could prevent venous reflux from the IVC into the kidney.

BACKGROUND: Monitoring of renal function after kidney transplantation (KT) is performed by measuring serum creatinine (SCr), urine volumes (UV), and glomerular filtration rate (GFR). Other methods based on oxygen metabolism, such as the renal venous oxygen pressure (PrvO2), may be useful. The aim of this study was to explore the correlation between PrvO2 and SCr, UV, and GFR 5 days after KT (SCr5, UV5, and GFR5, respectively).
METHODS: We conducted a prospective cohort study in adults scheduled for living donor KT. A venous blood sample was taken from the renal vein after declamping the renal artery, and blood gas determinations were made. Correlation analyses between PrvO2 and SCr5, UV5, and GFR5 were done by calculating Spearman\'s correlation coefficient with generalized linear models (GLM). A Spearman\'s correlation analysis was performed between the percentage decrease in SCr (%ΔSCr) and PrvO2. A GLM was also performed to determine the association of PrvO2 with slow graft function (SGF).
RESULTS: The study included 42 patients, of whom 67% were men. The median age was 31 years (IQR, 27-43.5). PrvO2 was negatively correlated with SCr5 (ρ = -0.53, P = .003), and positively correlated with GFR5 (ρ = 0.49, P = .001) and %ΔSCr (ρ = 0.47, P = .002). A higher PrvO2 was associated with an increase in GFR in univariable (β = 1.24, 95% CI, 0.56-1.93, P = .001) and multivariable (β = 1.24, 95% CI, 0.53-1.94, P = .001) analyses. No association was found between PrvO2 and SGF.
CONCLUSIONS: PrvO2 could be used to monitor renal function in the first 5 days after related living-donor KT, given its good correlation with SCr and GFR.

The adrenal gland is a retroperitoneal organ with intimate relationships with neighboring organs but also with the large retroperitoneal vessels. Our aim was to study the vascular relationships of the adrenal gland with the large abdominal vessels. Our work is an anatomical dissection of 80 fresh cadaveric adrenals. The subjects didn\'t have a history of retroperitoneal surgery. Dissection conditions were similar to those in the living. All measurements were made in situ. On the right side, the average distance between the adrenal gland and the renal vein (DR) was 13 mm (0-20). In one case, the adrenal gland laid directly on the right renal vein (DR = 0). The average length L, over which the right adrenal gland entered behind the inferior vena cava (IVC), was 8 mm (0-12). In 4 cases, the right adrenal was lateral to the IVC and in 6 cases the length L exceeded 10 mm. On the left side, the mean distance DL, separating the adrenal gland from the left renal vein was 8 mm with extremes ranging from 0 mm to 18 mm. In eleven cases, the adrenal gland laid directly on the left renal vein. The right adrenal gland has a close relationship with the IVC and is often located behind it. This close relationship helps to explain the increased incidence of IVC lesions during surgery. The left adrenal gland has an intimate relationship with the left renal vein and often lies on top of it. This explains the risk of injury to the left renal pedicle during left adrenal surgery.

The outcome of renal vein thrombosis, in particular as for the long-term impact on kidney function, is not fully known. We aimed to study the natural course and outcomes of patients with renal vein thrombosis, in a large, single-center cohort.
A single-center retrospective cohort study including patients who were diagnosed with renal vein thrombosis between January 2006 and September 2021 was analyzed. The main outcomes analyzed were worsening kidney function, defined as a decrease in eGFR of at least 40% from baseline, and all-cause mortality.
Eighty-seven patients were included, 56.3% were female, median age was 57 years. Malignancy was the most common cause of renal vein thrombosis (60.9%), followed by post-surgery and trauma (16.1%) and nephrotic syndrome (12.6%). At initial presentation, 65.5% of the patients were asymptomatic; the main signs and symptoms were gross hematuria (20.7%), flank pain (18.4%), and flank tenderness (9.2%). During follow-up, 18 (21.4%) patients experienced worsening kidney function and 57 (65.5%) died. Multivariable analyses showed that the risk of worsening kidney function was higher in patients with nephrotic syndrome (hazard ratio [HR] 18.41; 95% confidence interval [CI], 1.57-216.04), body weight ≥ 60 kg (HR 4.82; 95% CI 1.43-16.32), and malignancy (HR 9.10; 95% CI 1.05-78.63). Symptomatic acute renal vein thrombosis was associated with a lower risk of worsening kidney function compared to asymptomatic or symptomatic chronic renal vein thrombosis (HR 0.12; 95% CI 0.01-0.96). Malignancy (HR 5.45; 95% CI 2.58-11.54), age ≥ 75 years (HR 3.44; 95% CI 1.49-7.93), and serum albumin < 3.0 g/dL (HR 2.88; 95% CI 1.65-5.05) were associated with an increased mortality risk.
Renal vein thrombosis is associated with a high rate of worsening kidney function and mortality. It is crucial to promptly identify patients at high risk and initiate early treatment to prevent negative outcomes.

BACKGROUND: Horseshoe kidney (HSK) is a common developmental anomaly which can be associated with many atypical anatomical variants of blood supply. The aim of this study was to identify the anatomical variants of renal veins supplying HSK, with particular emphasis on their relationship with the arterial system.
METHODS: The analysis included 94 patients with HSK and 248 persons with normal kidneys (NK). Based on computed tomography-angiography, the number of renal arteries and veins was determined, along with the levels the arteries branched off the aorta and the veins communicated to their parental vessels.
RESULTS: Four hundred and twenty-three renal arteries (4.5 per person) and 364 renal veins (3.78 per persons) were found in HSK group (p = 0.004), as compared with 598 arteries (2.41 per person) and 567 veins (2.29 per person) in the NK group (p = 0.025). Mean number of renal veins in women with HSK was higher than in men (4.11 vs. 3.72 per patient, p = 0.03). In the HSK group, the number of renal arteries correlated significantly with the number of renal veins only among men (ks = 0.35, p = 0.009). In patients with NK, significant correlations between the number of renal arteries and renal veins were found both in the whole group and among men and women.
CONCLUSIONS: Horseshoe kidneys are drained by a higher number of renal veins than NK, especially in women; this also refers to accessory renal veins. The number of renal veins for HSK is less dependent on the number of corresponding arteries than these for NK.

There are limited data at a population level on the burden, risk factors, and long-term outcomes of neonatal renal vein thrombosis (nRVT). We conducted a population-based cohort study to understand the epidemiology and outcomes of nRVT over a 25-year period in Ontario.
Using linked administrative health databases, all hospitalized neonates ≤28 days born in Ontario between 1992 and 2016 with nRVT were identified. The primary outcome was to calculate the incidence of nRVT and trend over time in Ontario. We also determined the risk factors associated with nRVT as well as the risk of long-term outcomes after nRVT, including CKD, ESKD, all-cause mortality, and hypertension (HTN) compared with the healthy neonatal population without nRVT.
The annual incidence rate of nRVT was 2.6 per 100,000 live births (n=85). Presence of respiratory distress syndrome (OR, 8.01; 95% CI, 4.90 to 13.1), congenital heart disease (OR, 9.1; 95% CI, 5.05 to 16.4), central venous catheterization (OR, 3.9; 95% CI, 1.89 to 7.93), maternal preeclampsia (OR, 2.8; 95% CI, 1.6 to 4.79), and maternal diabetes (OR, 2.36; 95% CI, 1.36 to 4.07) conferred the highest risk for nRVT. Over a median follow-up of 15 years and after adjusting for confounders, neonates with nRVT versus the comparator cohort had a 15.5-fold risk of CKD, HTN, or death (n=49 [58%] versus n=90,050 [3%]; 95% CI, 11.7 to 20.6); 12.3-fold increased risk of CKD or death (n=39 [46%] versus n=32,016 [1%]; 95% CI, 8.9 to 16.8); and a 15.7-fold increased risk of HTN (n=33 [39%] versus n=64,458 [2%]; 95% CI, 11.1 to 21.1). None of the nRVT cohort developed ESKD. The median time to composite outcome of CKD, HTN, or death was 11.1 years.
Patients with a history of nRVT remain at higher risk than the general population for long-term morbidity or mortality, indicating the need for long-term follow-up.

OBJECTIVE: Control of adrenal vein is the key of adrenal surgery. Its anatomy can present variations. Our aim was to study the anatomy of the main left adrenal vein (LAV) and its anatomical variations.
METHODS: Our work is based on dissection of 40 cadavers. We studied the number of LAV and the drainage of the main adrenal vein as well as its level of termination. We measured its length, its width and the distance between its termination level and the termination level of the gonadal vein (GV).
RESULTS: The average length of the LAV was 21 mm its mean width was 5 mm. It ended in 100% of cases at the upper edge of the left renal vein after an anastomosis with the lower phrenic vein in 36 cases (90%) and without anastomosis with the lower phrenic vein in four cases (10%). The left adrenal vein ended at the upper edge of the left renal vein either at the same level as the termination of the left GV in 14 cases (35%) or within the termination of the left GV in 26 cases (65%) by an average of 8 mm. The LAV was unique central vein in 22 cases (55%) and in 12 cases (30%), a major central adrenal vein with several small veins was found.
CONCLUSIONS: The LAV is usually unique but there are variations in number. There are also variations in the level of its termination in the left renal vein as well as its anastomosis. During surgery, in case of difficulty, the left GV and the adrenal-diaphragmatic venous trunk could be used as benchmarks.

OBJECTIVE: To share our initial experience with the modified vein clamping technique for the treatment of renal cell carcinoma complicated with level I-II IVC thrombi.
METHODS: From March 2018 to April 2021, 11 patients with renal cell carcinoma (RCC) involving an IVC tumour thrombus were admitted to our hospital. They all underwent laparoscopic radical nephrectomy and IVC thrombectomy (LRN-IVCTE) using a modified vein clamping technique.
RESULTS: All procedures were successfully completed without conversion to open surgery. The median operative time was 185.00 min (145.00-216.00 min); the median estimated blood loss was 200.00 ml (155.00-300.00 ml), and four patients received an intraoperative transfusion. In addition, the median IVC clamping time was 18.00 min (12.00-20.00 min); the median postoperative hospital stay was 6.00 days (4.00-7.00 days), while the median follow-up period was 28.00 months (4.00-34.00 months).
CONCLUSIONS: The modified vein clamping technique for the treatment of renal cell carcinoma complicated with level I-II IVC thrombi may be a safe and technically feasible alternative technique.

BACKGROUND: Preoperative multisection computed tomography evaluation can provide necessary anatomic information in minimally invasive surgeries. This study was done to estimate the preva-lence and pattern of variations of renal vasculature through contrast-enhanced computed tomogra-phy in patients referred to the radiology department of a tertiary care hospital.
METHODS: A descriptive cross-sectional study was conducted from 6th April 2016 to 6th April 2017. Ethical approval was taken. The triple-phase contrast-enhanced computed tomography was per-formed on 188 patients enrolled through convenient sampling. The images were evaluated in un-enhanced, arterial, and venous phases for the vascular variants. Data were analyzed based on the anatomical types of variations and descriptive statistics such as frequency and percentage using the Statistical Package for the Social Sciences.
RESULTS: Out of the 188 patients, 60 (31.9%) had accessory renal arteries. The most common variant was hilar arteries which comprised 38 cases (20.2%) whereas polar arteries were present in 21 (11.1%)cases and the capsular artery was present in one (0.5%) case. Early bifurcation of the renal artery was noted in 15 (8%) cases with 10 (5.3%) on the right and 5 (2.7%) on the left side. Twelve (6.3%) cases of the double right renal vein were noted whereas retroaortic left renal vein was noted in only 4(2.1%) cases.
CONCLUSIONS: Based on our study, almost one in three patients had accessory renal arteries and eighty-five out of a thousand patients had variants of renal veins.

To evaluate the short- and long-term outcomes of RPA in a large multicentric series.
The current knowledge on RPA for portal reconstruction during LT in patients with diffuse PVT and a large splenorenal shunt is poor and limited to case reports and small case series.
All consecutive LTs with RPA performed in 5 centers between 1998 and 2020 were included. RPA was physiological provided it drained the splanchnic venous return through a large splenorenal shunt (≥ 1 cm diameter). Complications of PHT, long-term RPA patency, and patient and graft survival were assessed. RPA success was achieved provided the 3 following criteria were all fulfilled: patients were alive with patent RPA and without clinical PHT.
RPA was attempted and feasible in 57 consecutive patients and was physiological in 51 patients (89.5%). Ninety-day mortality occurred in 5 (8.5%) patients, and PHT-related complications occurred in 42.9% of patients. With a median follow-up of 63 months, the 1-, 3- and 5-year patient and graft survival rates were 87%, 83%, and 76% and 82%, 80%, and 73%, respectively. The primary and primary-assisted patency rates at 5 years were 84.5% and 94.3%, respectively. Success was achieved in 90% (27/30) of patients with a follow-up ≥5 years.
Despite a high rate of PHT-related complications, excellent long-term patient and graft survival could be achieved. RPA could be considered successful in the vast majority of patients. The expanded use of RPA is warranted.