Renal fascia: its radiographic importance

Preoperative analysis of factors associated with prolonged pneumoretroperitoneum time during retroperitoneal laparoscopic nephroureterectomy for upper tract urothelial carcinoma

BACKGROUND

Prolonged laparoscopic nephroureterectomy (LNU) for upper tract urothelial cancer (UTUC) can increase the frequency of intravesical recurrence after surgery. Therefore, it is important for urological surgeons to have knowledge on preoperative risk factors for prolonged LNU. However, few studies have investigated the risk factors for prolonged LNU. We hypothesized that the quantity of perirenal fat affects the pneumoretroperitoneum time (PRT) of retroperitoneal LNU (rLNU). This study aimed to investigate the preoperative risk factors for prolonged PRT during rLNU.

METHODS

We reviewed the data of 115 patients who underwent rLNU for UTUC between 2013 and 2021. The perirenal fat thickness (PFT) observed on preoperative computed tomography (CT) images was used to evaluate the perinephric fat quantity. Preoperative risk factors for PRT during rLNU were analyzed using logistic regression models. The cutoff value for PRT was determined based on the median time.The cutoff values for fat-related factors influencing PRT were defined according to receiver operating characteristic curve analysis.

RESULTS

The median PRT for rLNU was 182 min (interquartile range, 155-230 min). The cutoff values of posterior, lateral, and anterior PFTs were 15 mm, 24 mm, and 6 mm, respectively. Multivariate analysis revealed that a posterior PFT ≥ 15 mm (odds ratio [OR], 2.72; 95% confidence interval, 1.04-7.08; p = 0.0410) was an independent risk factor for prolonged PRT.

CONCLUSIONS

Thick posterior PFT is a preoperative risk factor for prolonged PRT during rLNU. For patients with UTUC and thick posterior PFT, surgeons should develop optimal surgical strategies, including the selecting an expert surgeon as a primary surgeon and the selecting transperitoneal approach to surgery or open surgery.

The potential mechanisms underlying the modulating effect of perirenal adipose tissue on hypertension: Physical compression, paracrine, and neurogenic regulation

Hypertension, a prevalent global cardiovascular disease, affects approximately 45.4 % of adults worldwide. Despite advances in therapy, hypertension continues to pose a significant health risk due to inadequate management. It has been established that excessive adiposity contributes majorly to hypertension, accounting for 65 to 75 % of primary cases. Fat depots can be categorised into subcutaneous and visceral adipose tissue based on anatomical and physiological characteristics. The metabolic impact and the risk of hypertension are determined more significantly by visceral fat. Perirenal adipose tissue (PRAT), a viscera enveloping the kidney, is known for its superior vascularisation and abundant innervation. Although traditionally deemed as a mechanical support tissue, recent studies have indicated its contributing potential to hypertension. Hypertensive patients tend to have increased PRAT thickness compared to those without, and there is a positive correlation between PRAT thickness and elevated systolic blood pressure. This review encapsulates the anatomical characteristics and biogenesis of PRAT. We provide an overview of the potential mechanisms where PRAT may modulate blood pressure, including physical compression, paracrine effects, and neurogenic regulation. PRAT has become a promising target for hypertension management, and continuous effort is required to further explore the underlying mechanisms.

The Utility of Perirenal Fat in Determining the Risk of Onset and Progression of Diabetic Kidney Disease

BACKGROUND

Perirenal fat (PRF) has multiple effects on the kidney through its physical structure and adipocytokine-secreting ability. The present study explored the relationship between PRF thickness and the onset and progression of albuminuria in patients with diabetes.

METHODS

In the cross-sectional analysis, we screened 959 patients from 8764 subjects with type 2 diabetes mellitus (T2DM) who met the inclusion criteria and measured their perirenal fat thickness (PFT) using color Doppler ultrasound. A group of laboratory indexes were included in the analysis models. In a longitudinal study, a total of 218 patients with a baseline UACR <30 mg/g were included in the follow-up study.

RESULTS

In a cross-sectional analysis, patients with diabetes and higher PFT presented with higher albuminuria. Multiple logistic regression analysis indicated that PFT was an independent risk factor for the degree of albuminuria in patients with T2DM (odds ratio = 4.186, 95%CI: 2.290-7.653, P < 0.001). In a longitudinal study, 218 albuminuria-free patients with T2DM at the baseline were followed up for a mean of 12.3 months. Based on the cutoff value from the ROC diagnostic test in the cross-sectional study, patients were divided into two groups: higher PFT (H-PFT) and lower PFT (L-PFT). Kaplan-Meier survival curve analysis showed that H-PFT was associated with a higher incidence of albuminuria than L-PFT (log-rank test, χ2 = 4.522, P = 0.033). Cox regression analysis showed that PFT was a risk factor for the earlier onset of albuminuria (hazard ratio 2.83, 95% CI: 1.34-4.88, P < 0.001).

CONCLUSIONS

PRF evaluated by color Doppler ultrasound is an easy and reliable tool for predicting the onset and progression of albuminuria in patients with T2DM.

Perirenal Fat Thickness Is Significantly Associated With the Risk for Development of Chronic Kidney Disease in Patients With Diabetes

Perirenal fat is adjacent to kidneys and active in metabolism and adipokine secretion. We aimed to investigate whether perirenal fat is an independent predictor for chronic kidney disease (CKD) and compared it with total, subcutaneous, or visceral fat in patients with diabetes. Perirenal fat thickness (PRFT) was measured by computed tomography, and total body fat (TBF), subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) were assessed by DEXA. In cross-sectional analysis, patients with higher PRFT had a lower estimated glomerular filtration rate (eGFR). Multiple linear regression analysis showed a negative correlation between PRFT and eGFR after confounders adjustment. No association between eGFR and TBF, SAT, or VAT was observed. Longitudinally, 190 patients with type 2 diabetes mellitus (T2DM) without CKD at baseline were followed for 2 years. A total of 29 participants developed CKD. After VAT-based multivariate adjustment, each SD (per-SD) increment in baseline PRFT was associated with a higher incidence of CKD (hazard ratio 1.67, 95% CI 1.04-2.68), while TBF, SAT, and VAT were not. Furthermore, PRFT predicted CKD, with a C-statistic (95% CI) of 0.668 (0.562, 0.774), which was higher than that of TPF [0.535 (0.433, 0.637)], SAT [0.526 (0.434, 0.618)], and VAT [0.602 (0.506, 0.698)]. In conclusion, with perirenal fat there was a higher predictive value for CKD than with total, subcutaneous, or visceral fat in T2DM.

Perirenal Adipose Tissue Inflammation: Novel Insights Linking Metabolic Dysfunction to Renal Diseases

A healthy adipose tissue (AT) is indispensable to human wellbeing. Among other roles, it contributes to energy homeostasis and provides insulation for internal organs. Adipocytes were previously thought to be a passive store of excess calories, however this view evolved to include an endocrine role. Adipose tissue was shown to synthesize and secrete adipokines that are pertinent to glucose and lipid homeostasis, as well as inflammation. Importantly, the obesity-induced adipose tissue expansion stimulates a plethora of signals capable of triggering an inflammatory response. These inflammatory manifestations of obese AT have been linked to insulin resistance, metabolic syndrome, and type 2 diabetes, and proposed to evoke obesity-induced comorbidities including cardiovascular diseases (CVDs). A growing body of evidence suggests that metabolic disorders, characterized by AT inflammation and accumulation around organs may eventually induce organ dysfunction through a direct local mechanism. Interestingly, perirenal adipose tissue (PRAT), surrounding the kidney, influences renal function and metabolism. In this regard, PRAT emerged as an independent risk factor for chronic kidney disease (CKD) and is even correlated with CVD. Here, we review the available evidence on the impact of PRAT alteration in different metabolic states on the renal and cardiovascular function. We present a broad overview of novel insights linking cardiovascular derangements and CKD with a focus on metabolic disorders affecting PRAT. We also argue that the confluence among these pathways may open several perspectives for future pharmacological therapies against CKD and CVD possibly by modulating PRAT immunometabolism.

Novel insight into perirenal adipose tissue: A neglected adipose depot linking cardiovascular and chronic kidney disease

Obesity is associated with adverse metabolic diseases including cardiovascular disease (CVD) and chronic kidney disease (CKD). These obesity-related diseases are highly associated with excess fat accumulation in adipose tissue. However, emerging evidence indicates that visceral adiposity associates more with metabolic and cardiovascular risk factors. Perirenal adipose tissue, surrounding the kidney, is originally thought to provides only mechanical support for kidney. However, more studies demonstrated perirenal adipose tissue have a closer association with renal disease than other visceral fat deposits in obesity. Additionally, perirenal adipose tissue is also an independent risk factor for CKD and even associated more with CVD. Thus, perirenal adipose tissue may be a connection of CVD with CKD. Here, we will provide an overview of the perirenal adipose tissue, a neglected visceral adipose tissue, and the roles of perirenal adipose tissue linking with CVD and CKD and highlight the perirenal adipose tissue as a potential strategy for future therapeutics against obesity-related disease.

Perirenal Fat: A Unique Fat Pad and Potential Target for Cardiovascular Disease

Although visceral obesity is recognized as a risk factor for cardiovascular diseases (CVDs), the efficacy of omental fat removal in CVD treatment is still controversial. There is a need to identify other visceral fat depots for CVD management. This review aims to provide a summary on perirenal fat as an important risk factor for CVD. Studies on epidemiology, anatomy, and function of perirenal fat were reviewed. Observational studies in humans suggest that excessive perirenal fat increases the risk of hypertension and coronary heart disease. Anatomy studies prove that perirenal fat is unique compared to other connective tissues in that it is well vascularized, innervated, and drains into the lymphatic system. Other special morphological features include a complete fascia border, sympathetic-independent development of architecture, and proximity to the kidneys. Based on these anatomical features, perirenal fat regulates the cardiovascular system presumably via neural reflex, adipokine secretion, and fat-kidney interaction. These new insights suggest that perirenal fat may constitute a promising target for CVD management.

Anatomic pathways of peripancreatic fluid draining to mediastinum in recurrent acute pancreatitis: visible human project and CT study

Background

In past reports, researchers have seldom attached importance to achievements in transforming digital anatomy to radiological diagnosis. However, investigators have been able to illustrate communication relationships in the retroperitoneal space by drawing potential routes in computerized tomography (CT) images or a virtual anatomical atlas. We established a new imaging anatomy research method for comparisons of the communication relationships of the retroperitoneal space in combination with the Visible Human Project and CT images. Specifically, the anatomic pathways of peripancreatic fluid extension to the mediastinum that may potentially transform into fistulas were studied.

Methods

We explored potential pathways to the mediastinum based on American and Chinese Visible Human Project datasets. These drainage pathways to the mediastinum were confirmed or corrected in CT images of 51 patients with recurrent acute pancreatitis in 2011. We also investigated whether additional routes to the mediastinum were displayed in CT images that were not in Visible Human Project images.

Principal Findings

All hypothesized routes to the mediastinum displayed in Visible Human Project images, except for routes from the retromesenteric plane to the bilateral retrorenal plane across the bilateral fascial trifurcation and further to the retrocrural space via the aortic hiatus, were confirmed in CT images. In addition, route 13 via the narrow space between the left costal and crural diaphragm into the retrocrural space was demonstrated for the first time in CT images.

Conclusion

This type of exploration model related to imaging anatomy may be used to support research on the communication relationships of abdominal spaces, mediastinal spaces, cervical fascial spaces and other areas of the body.

Renal subcapsular abscess

Renal subcapsular abscess is reported with description of findings by conventional radiography, computerized axial tomography, arteriography, and ultrasonography. The latter was especially helpful in permitting delineation of the lesion, and in facilitating its aspiration and resolution.