Contemporary outcomes and prediction of adherent perinephric fat at partial nephrectomy: a systematic review

Evaluation of factors predicting adherent perinephric fat in laparoscopic retroperitoenal partial nephrectomy

BACKGROUND

Adherent perinephric fat (APF) represents a clinical situation, which increases the complexity of renal surgery. We aimed to elucidate the common characteristics of patients with APF and to evaluate the extent of outcome differentiation depending on the presence of APF.

METHODS

We made a retrospective review of a prospectively maintained database of patients who underwent laparoscopic retroperitoneal partial nephrectomy for a localized renal tumor at our institution from May 2010 to January 2022. 238 patients were included in this study. Demographic, intraoperative, postoperative data and characteristics and comorbidities of all patients were evaluated. Radiographic data (tumor size, localization, side, exophytic rate, perinephric fat density [PFD]) were determined from preoperative contrast-enhanced abdominal computed tomography imaging studies. Adherent perinephric fat was classified intraoperatively by the operating surgeon. The patients were divided into two groups as the APF group and the non-APF group and predictors causing APF were investigated.

RESULTS

Intraoperative and postoperative complication rates were higher in the APF group, but the difference between intraoperative complication rates, operation duration and amount of bleeding were statistically significant. (11.6% vs. 5.9%, p = 0.033; 130 vs. 120 min, p = 0.024; 60 vs. 30 cc, p = 0.016, respectively). The most common complications were conversion to open surgery due to failure of dissection of the tumor and bleeding requiring intraoperative transfusion in the groups. On multivariable analysis using stepwise regression model, we identified male gender (OR = 3.328; 95% Cl = 1.552-7.133; p = 0.002), PFD>-100.4 Hounsfield Unit (HU) (OR = 3.24; 95% Cl = 1.549-6.777; p = 0.002) and presence of diabetes mellitus (DM) (OR = 2.513; 95% Cl = 1.192-5.299; p = 0.015), as predictor of APF.

CONCLUSION

Male gender, presence of DM and PFD>-100.4 HU are predictors of APF. This endpoint is promising for application in gaining knowledge preoperatively about the dissection difficulty level.

Impact of prior endoscopic management of upper tract urothelial carcinoma on nephroureterectomy complexity

PURPOSE

Kidney-sparing endoscopic surgery is considered the preferred approach for the treatment of low-risk upper tract urothelial cancer (UTUC), yet its impact on subsequent radical nephroureterectomy's (RNU) surgical complexity remains uncertain. This study aims to evaluate the effect of prior endoscopic procedures on peri-operative outcomes of UTUC patients undergoing RNU.

METHODS

A retrospective analysis of 176 consecutive UTUC patients who underwent RNU from July 2008 to July 2023 at a single tertiary center. Demographic, clinical, and pathological data were recorded. The cohort was stratified based on the intention of endoscopic intervention: patients who did not undergo ureteroscopy and those who underwent a single diagnostic ureteroscopy only (non-mURS group) were compared to those who underwent multiple endoscopic treatments with laser ablation as part of a kidney-sparing strategy before RNU referral (mURS group). Statistical analyses addressed the correlations between ureteroscopy frequency and surgical complexity. Multivariate regression analysis was conducted to assess surgical complexity.

RESULTS

Among 176 patients who underwent RNU, 63 (35.7%) were included in the mURS group, and 113 (64.3%) in the non-mURS group. The mURS patients had longer RNU duration (306 ± 114 vs. 269 ± 114 min, p = 0.005), greater blood loss (hemoglobin decrease of 3.5 ± 1.1 vs. 1.02 ± 0.49 g/dL, p < 0.001), increased peri-ureteral adhesions (88.9% vs. 25.7%, p < 0.001), higher postoperative opioid use (87% vs. 53%, p < 0.001), and higher prevalence of fibrosis in pathology reports (88.9% vs. 30.9%, p < 0.001). No significant differences were found in post-operative complications.

CONCLUSION

Pre-RNU endoscopic treatment for UTUC is associated with increased surgical complexity of RNU without adversely affecting postoperative complication rates.

Evaluating the adherent perinephric fat risk score in East Asian populations and its correlation with non-alcoholic fatty liver disease

BACKGROUND AND AIMS

This study evaluated the predictive value of the APF risk score in East Asian patients undergoing open nephrectomy and its correlation with hypertension and NAFLD.

METHODS AND RESULTS

A retrospective study used the clinical data of 82 patients who underwent ON between January 2010 and December 2022. Per their APF score, patients were categorized into groups A (0-2 points) and B (3-4 points). Logistic regression analyses were used to compare the overall clinical data between the two groups and identify potential risk factors. Intraoperative APF prevalence was significantly higher in group B compared to group A (P < 0.001). Group B patients were older (63.06 ± 8.88 vs. 53.69 ± 15.21 years) and had higher incidences of hypertension (P < 0.001), diabetes (P = 0.002), and NAFLD (P < 0.001). Preoperative CT scans showed significant differences in posterior (P = 0.009) and lateral perinephric fat thickness (P < 0.001), and perinephric stranding (P < 0.001). Group B also had a higher proportion of malignant tumors (P = 0.039). Multivariate logistic regression revealed that NAFLD (OR = 9.053, P = 0.010) and hypertension (OR = 5.181, P = 0.025) were highly correlated with APF risk scores.

CONCLUSIONS

In this study, we found that the newly developed APF risk score had significant value in predicting APF in East Asian patients undergoing open nephrectomy. Additionally, NAFLD and hypertension were highly correlated with elevated APF risk scores.

Assessing the Prognostic Utility of the New Mayo Adhesive Probability Score in East Asian Populations and its Correlation with Metabolic-Associated Fatty Liver Disease

We assessed the prognostic utility of the new perinephric fat adherence risk score - Mayo Adhesive Probability (MAP), in patients of East Asian ethnicity undergoing either laparoscopic partial nephrectomy (LPN) or laparoscopic radical nephrectomy (LRN). A retrospective analysis of clinical data was carried out on 169 patients who either underwent LPN or LRN surgery. These patients were categorized into two groups, group A (0-2 points) and group B (3-4 points) using the new MAP score. The overall clinical data between these two groups was compared and potential risk factors were investigated using logistic regression analyses. The new MAP score yielded an area under the curve of 0.761 (95 % CI: 0.691-0.831), indicating its effectiveness. Group B had a significantly higher incidence of adherent perirenal fat (APF) during surgery (p<0.001) and had a greater average age (p<0.001). There was an increased prevalence of hypertension (p=0.009), type 2 diabetes mellitus (p<0.001), and MAFLD (p<0.001) in group B. Additionally, there were significant differences in posterior perinephric fat thickness (p<0.05), lateral perinephric fat thickness (p<0.001), and perinephric stranding (p<0.001) between the two groups. The new MAP score holds significance in predicting APF in people of East Asian ethnicity undergoing LPN or LRN, and there is a strong correlation between elevated MAP scores and risk factors such as MAFLD and advanced age.

Prognostic value of preoperative radiographic perinephric fat features in renal cell carcinoma patients undergoing surgery

BACKGROUND

We aimed to assess the prognostic importance of perinephric fat features in images of patients with non-metastatic renal cell carcinoma (RCC) undergoing surgery.

METHODS

We enrolled RCC patients who underwent surgical treatment between 2011 and 2019. Two characteristics, including perinephric fat thickness and perinephric fat stranding, were evaluated using preoperative computed tomography or magnetic resonance images. The association between perinephric fat characteristics and disease progression was examined by Kaplan-Meier survival analysis and Cox regression model.

RESULTS

In a multivariate Cox proportional hazards model adjusting for tumor stage, intratumoral necrosis, and neutrophil-to-lymphocyte ratio, we found that patients in the thin perinephric fat group (<1 cm) had a poorer progression-free survival (PFS) compared to the thick perinephric fat group (≥1 cm) (HR 2.8; 95% CI 1.175-6.674, p = 0.02). Additionally, the fat stranding group had a poorer PFS than the non-stranding group (HR 3.852; 95% CI 1.082-13.704, p = 0.037). The non-stranding with thick perinephric fat group exhibits the highest cumulative PFS while the stranding with thin perinephric fat group has the lowest cumulative PFS. In receiver operating characteristic curve analysis, combing these two perinephric fat characteristics with tumor stage can achieve a better discriminatory power than tumor stage alone.

CONCLUSIONS

Our study indicates that the evaluation of image-based perinephric fat features is a simple, straightforward, reproducible tool for predicting RCC prognosis and may assist in preoperative risk stratification.

Is the Mayo Adhesive Probability Score Predictive in Patients Undergoing Percutaneous Nephrolithotomy?

Introduction: Mayo Adhesive Probability (MAP) score was developed as a means to predict the presence of adherent perinephric fat. Our aim was to determine the predictive value of the MAP score on surgical outcomes in patients undergoing standard adult percutaneous nephrolithotomy (PCNL). Materials and Methods: We retrospectively analyzed the data from 130 renal units that underwent PCNL between January 2022 and 2023. MAP scores 0-2 were classified as low, whereas MAP scores 3-5 were classified as high. The impact of the MAP score on perioperative and postoperative outcomes was studied. All statistical analyses were performed using SPSS 24.0 for Windows. Results: The median age of the patients at the time of surgery was 48 (21) years, with a female-to-male ratio of 1:1.82. The median MAP score was 2 (2), with 43.8% of patients falling into the high MAP score group. Advanced age, hypertension history, low estimated glomerular filtration rate (eGFR) levels, and low renal parenchymal thickness were significantly higher in the high MAP score group (P = .010, P = .004, P = .001, and P = .005, respectively). Female patients had a significantly higher MAP score of 0 (P = .021). Operation time, postoperative hematocrit decrease, blood transfusion rate, postoperative fever rate, hospitalization, and stone-free rates were comparable between the low and high MAP score groups (P = .535, P = .209, P = .313, P = .289, P = .281, and P = .264, respectively). Gender and eGFR levels were shown to be significant predictors of a MAP ≥3 (P = .004 and P = .003, respectively). Conclusion: The present study showed that the MAP score groups had similar perioperative and postoperative results. Low eGFR levels and the male gender were associated with MAP score ≥3. To determine the predictive MAP score value for PCNL outcomes, more prospective studies are needed.

Intraoperative Ultrasound Can Facilitate Laparoscopic Partial Nephrectomy in Adherent Perinephric Fat

Background: Adherent perinephric fat (APF) is one of the challenging factors of laparoscopic partial nephrectomy (LPN). The aim of this study was to investigate the effect of intraoperative laparoscopic ultrasound (ILUS) on determining renal tumor localization and dissection in patients with APF who underwent LPN. Methods: Prospectively collected data from 517 patients who underwent LPN from October 2010 to September 2020 in tertiary university hospital were evaluated retrospectively. The cohort was divided into two main groups according to the Mayo Adhesive Probability (MAP) score: Group 1 (MAP score ≤3) and Group 2 (MAP score ≥4). After implementing propensity score-matched analysis including the complexity of tumor, age, and body mass index, Group 1 consisted of 202 patients with ≤3 MAP score and Group 2 included 46 patients. Then, both groups were allocated into two subgroups according to whether ILUS was used. Demographics, perioperative features such as perirenal fatty tissue dissection, tumor excision, operation time, and perioperative outcomes accepted as trifecta, considering warm ischemia time, negative surgical margin, and complications were compared. Results: In Group 1, ILUS use did not seem to affect perioperative outcomes in both subgroups. However, ILUS has a positive effect on perirenal fatty tissue dissection (10 versus 19 minutes, P = .011), tumor excision (4 versus 7 minutes, P = .005), and operation time (78 versus 90 minutes, P = .046) in Group 2. Trifecta outcomes were also better in higher MAP scores and ultrasound-used subgroups (P = .019). Conclusions: ILUS should be considered a helpful and effective instrument in overcoming APF in LPN. It might also have a positive effect on trifecta outcomes.

Surgeon preimplantation macroscopic graft appraisal improves risk stratification of deceased kidney donors: a prospective study

BACKGROUND

Preimplantation scores assist with correct kidney graft allocation, but macroscopic graft features have never been evaluated in this scenario.

METHODS

We designed a graft appraisal questionnaire, assessed its reproducibility by comparing the senior and junior surgeon responses and evaluated which features can predict transplant outcomes in 202 patients transplanted from 144 donors at a tertiary center. We created new prediction models in combination with validated preimplantation scores. The primary outcome was graft loss or eGFR<30 mL/min/1.73 m² at six months and secondary outcomes were delayed graft function, early graft loss and graft function at six months.

RESULTS

Interrater correlation was very good for adherent perinephric fat (kappa=0.91) and acceptable for cortical surface roughness (kappa=0.51) and cortical color (kappa=0.47). Adherent perirenal fat (Odds ratio=4.77; 95% CI: 2.10-10.85) and surface roughness (OR=2.11, 95% CI: 1.25-3.58) were independent predictors of the primary outcome, improving the kidney donor risk index efficacy model (AUC 0.71 vs. 0.82, P≤0.001), while cortical color and adherent fat improved the Irish risk model for delayed graft function (AUC 0.76 vs. 0.82, P=0.03). We created nomograms to visually assess the risk of both endpoints.

CONCLUSIONS

Kidney graft macroscopic appraisal is reproducible between surgeons and can improve the accuracy of clinical preimplantational prediction scores.

Functional, oncological outcomes and safety of laparoscopic partial nephrectomy versus open partial nephrectomy in localized renal cell carcinoma patients with high anatomical complexity

PURPOSE

Partial nephrectomy (PN) is the main treatment strategy for localized renal cell carcinoma (RCC). However, for RCC with high anatomical complexity, PN remains a challenge for urologists. Therefore, this study aimed to evaluate the functional oncological outcomes and safety of laparoscopic partial nephrectomy (LPN) versus open partial nephrectomy (OPN) in localized RCC patients with highly anatomical complexity (R.E.N.A.L. score ≥ 10).

PATIENTS AND METHODS

We retrospectively studied 575 patients who underwent PN at our center between January 2007 and December 2017. After propensity score-matching (PSM), 137 patients treated with LPN and 54 patients treated with OPN were balanced into 97 and 44 pairs. Patient demographics, and extensive perioperative and prognostic data were recorded and compared.

RESULTS

In the matched group, the OPN group had significantly less eGFR loss than the LPN group (2.57 ml/min/1.73 m² vs. 31.59 ml/min/1.73 m², P < 0.001). The recurrence-free survival (P = 0.287), overall survival (P = 0.296), cancer-specific survival (P = 0.664), and cardiocerebrovascular disease-specific survival (P = 0.341) were equivalent between groups. The rates of minor (P = 0.621) and major (P = 0.647) complications were also similar between groups.

CONCLUSIONS

This PSM cohort study showed that OPN resulted in better renal function preservation than LPN in localized RCC patients with high anatomical complexity, and had comparable oncological and safety outcomes after long-term follow-up. These findings may help improve clinical decision-making for localized RCC patients with high anatomical complexity.

Value of Radiomics of Perinephric Fat for Prediction of Intraoperative Complexity in Renal Tumor Surgery

INTRODUCTION

The aim of this study was to assess the value of computed tomography (CT)-based radiomics of perinephric fat (PNF) for prediction of surgical complexity.

METHODS

Fifty-six patients who underwent renal tumor surgery were included. Radiomic features were extracted from contrast-enhanced CT. Machine learning models using radiomic features, the Mayo Adhesive Probability (MAP) score, and/or clinical variables (age, sex, and body mass index) were compared for the prediction of adherent PNF (APF), the occurrence of postoperative complications (Clavien-Dindo Classification ≥2), and surgery duration. Discrimination performance was assessed by the area under the receiver operating characteristic curve (AUC). In addition, the root mean square error (RMSE) and R2 (fraction of explained variance) were used as additional evaluation metrics.

RESULTS

A single feature logit model containing "Wavelet-LHH-transformed GLCM Correlation" achieved the best discrimination (AUC 0.90, 95% confidence interval [CI]: 0.75-1.00) and lowest error (RMSE 0.32, 95% CI: 0.20-0.42) at prediction of APF. This model was superior to all other models containing all radiomic features, clinical variables, and/or the MAP score. The performance of uninformative benchmark models for prediction of postoperative complications and surgery duration were not improved by machine learning models.

CONCLUSION

Radiomic features derived from PNF may provide valuable information for preoperative risk stratification of patients undergoing renal tumor surgery.

Pathology associated with adherent perirenal fat and its clinical effect

INTRODUCTION

The dissection of perirenal fat is of critical importance to kidney surgery and ease of dissection is more important when using minimally invasive approaches. This study aimed to determine the clinical, radiological, and pathological significance of adherent perirenal fat (APF).

MATERIALS AND METHODS

This prospective study included 22 patients scheduled for partial nephrectomy and 40 patients for donor nephrectomy. Intraoperative fat dissection time was recorded, and the complexity of perirenal fat dissection was surgeon-classified as easy, moderate, and difficult. Perirenal fat and subcutaneous fat thickness were measured. Measurement of perirenal fat depth and the Hounsfield unit (HU) for both perirenal and subcutaneous fields were performed using computed tomography (CT) images. All specimens were submitted for histopatological analysis. Researchers in each arm were blinded to other researchers' data.

RESULTS

Mean age of the patients was 51.3 ± 12.7 years. Mean perirenal fat dissection time was 15.0 ± 13.5 minutes. Patient demographics, BMI, nor occupational status differed between the 3 complexity of perirenal fat dissection groups. Radiological findings showed that there was a significant correlation between perirenal fat depth and complexity of perirenal fat dissection (P < .05), but not with HU measurements or subcutaneous fat thickness. Surgeon classification of the complexity of perirenal fat dissection was in accordance with the duration of dissection (P < .05). Perinephric fat contained more fibrous tissue in the patients with histologically proven APF than in those without (P < .05).

CONCLUSIONS

APF is a challenge during kidney surgery. Difficult dissection prolongs the duration of perirenal fat dissection and surgery. Perirenal fat thickness measured via preoperative CT might be used to predict APF.

The role of imaging in the management of renal masses

The wide availability of cross-sectional imaging is responsible for the increased detection of small, usually asymptomatic renal masses. More than 50 % of renal cell carcinomas (RCCs) represent incidental findings on noninvasive imaging. Multimodality imaging, including conventional US, contrast-enhanced US (CEUS), CT and multiparametric MRI (mpMRI) is pivotal in diagnosing and characterizing a renal mass, but also provides information regarding its prognosis, therapeutic management, and follow-up. In this review, imaging data for renal masses that urologists need for accurate treatment planning will be discussed. The role of US, CEUS, CT and mpMRI in the detection and characterization of renal masses, RCC staging and follow-up of surgically treated or untreated localized RCC will be presented. The role of percutaneous image-guided ablation in the management of RCC will be also reviewed.

Visceral fat is associated with high-grade complications in patients undergoing minimally invasive partial nephrectomy for small renal masses

Introduction:

Minimally invasive partial nephrectomy is standard of care treatment for small renal masses.

Objective:

We evaluated the relationship between subcutaneous and visceral obesity with high-grade postoperative 30-day complications in patients undergoing minimally invasive partial nephrectomy.

Methods:

We retrospectively identified 98 patients at our institution from 2014 to 2017 who underwent laparoscopic or robotic-assisted partial nephrectomy due to suspected renal cell carcinoma. Patients were stratified based on presence or absence of high-grade (Clavien ≥ IIIa) 30-day postoperative complications. Means were compared with the independent t test and proportions with chi-square analysis. Multivariate logistic regression was performed to determine independent predictors of high-grade 30-day complications.

Results:

Mean nephrometry score was 6.7 with 21 (21.4%) patients having hilar tumors. Mean estimation of blood loss was 207 mL, mean operating time was 223 min, and mean warm ischemia time was 23 min. The majority of patients had clear renal cell carcinoma (n = 83, 84.7%) and pT1a disease (n = 76, 77.6%) with negative margins (n = 89, 90.8%) on pathology. There were 5 (5.1%) patients who experienced a high-grade postoperative 30-day complication. Mean visceral fat index was an independent predictor of high-grade 30-day complications (odds ratio: 1.02; 95% confidence interval: 1.002–1.03; p = 0.027).

Conclusions:

Visceral obesity should be considered as a prognostic indicator of outcomes in patients undergoing surgical treatment for a small renal mass.

3D modeling in adherent perinephric fat prediction in nephron-sparing surgery planning in patients with localized renal neoplasms

STUDY OBJECTIVE

To develop a 3D-image based morphometry scoring system for Adherent Perinephric Fat (APF) prediction in nephron-sparing surgery in renal neoplasm patients.

MATERIALS AND METHODS

The retrospective study involved 391 patients who underwent a laparoscopic partial nephrectomy performed by five surgeons from January 2014 till December 2018. The surgery involved the 3D virtual operation planning with «Amira» 3D modeling software. With the multivariate logistic regression models, we developed a scoring system based on 3D-models. We tested the significance and sensitivity of new scoring system in a comparative ROC analysis with Mayo Adhesive Probability Score (MAP).

RESULTS

We found APF in 111 patients (28.4%). The univariate analysis revealed that significant indicators included mean age 59.88 (55-67) (p < 0.001), male sex (p < 0.001), Body Mass Index (BMI) >30 (21.47-35.08) kg/m² (p < 0.001), arterial hypertension (p < 0.001), coronary heart disease (p = 0.019), diabetes mellitus (p = 0.005), urolithiasis (p = 0.002). The multivariate regression analysis identified three most significant indicators in 3D models evaluation: additional >5 mm shadows in perirenal space OR = 7.3 (3.6-15.3) (p < 0.001), the number of shadows >5 OR = 3.8 (2.1-6.8) (p < 0.001), the wide shadow base at the renal parenchymal level OR = 0.293 (0.146-0.588) (p = 0.001). The scoring of these indicators comprises a new prediction scale (0-5). The ROC analysis revealed AUC 0.816 (95% CI 0.772-0.861) p < 0.001 of the MAP score, and AUC = 0.803 (95% CI 0.758-0.848) p < 0.001 of the scoring system developed in the present study.

CONCLUSIONS

The statistical findings comparison of the scoring system that we developed with those of MAP scale suggests that the scoring system is efficient and applicable.

Validation of the Mayo Adhesive Probability score as a predictor of adherent perinephric fat and outcomes in open partial nephrectomy

Background

Adherent perinephric fat (APF) contributes to surgical complexity and can be associated with adverse perioperative outcomes for partial nephrectomy (PN). The Mayo Adhesive Probability (MAP) score accurately predicts the presence of APF during robotic-assisted partial nephrectomy (RAPN). Our primary aim is to validate MAP score as a predictor of APF in open partial nephrectomy (OPNx).

Methods

We reviewed 105 consecutive OPNx (100 patients) performed by a single surgeon with intraoperative determination of APF. We evaluated the ability of the MAP score to discriminate between those with APF and those without APF by estimating the area under the receiver operating characteristic curve (AUROCC). The association of perioperative outcomes with APF was evaluated as well.

Results

Forty-three patients [49%; 95% confidence interval (CI), 39–59%] had intraoperative identification of APF. The MAP score had excellent ability to predict APF in OPNx (AUROCC, 0.82; 95% CI, 0.74–0.92). APF was observed in 6% of patients with a MAP score of 0-1, 27% with score 2, 52% with score 3, 75% with score 4, and 90% with score 5. The presence of APF was associated with longer operative times (P=0.004) and higher estimated blood loss (EBL) (P=0.003). Although not statistically significant, our study did suggest that APF may be associated with postoperative complications and prolonged length of stay (LOS) (>3 days).

Conclusions

MAP score accurately predicts the presence of APF in patients undergoing OPNx. APF is associated with longer operative time and higher blood loss in OPNx.

Correlation Between the Mayo Adhesive Probability Score and the Operative Time in Laparoscopic Donor Nephrectomy

BACKGROUND

Adherent perinephric fat (APF) is a known risk factor of surgical difficulty during laparoscopic donor nephrectomy (LDN). The Mayo Adhesive Probability (MAP) score predicts APF accurately. The aim of this study is to identify the association between MAP score and operative time in LDN.

METHODS

We retrospectively evaluated 154 kidney donors who underwent surgery from December 2017 to December 2019 at İstanbul Aydın University Hospital and İstinye University Hospital. All of the operations were done by 3 senior surgeons by a fully laparoscopic method. The MAP score was derived from computed tomography scans by 1 blinded reader. Demographic data, body mass index (BMI), MAP score, side selection, estimated glomerular filtration rate (eGFR), number of arteries and veins, operative time, hospital stay, and complications are recorded. Single and multiple variable analyses were used to evaluate the correlation between operative time and MAP score, BMI, side selection, and number of vascular structures.

RESULTS

A total of 154 patients (79 men, 75 women) with a mean age of 44.4 ± 12.72 were included in this study. None of the cases were converted to open nephrectomy. There were no major complications. Mean BMI was 27.59 ± 4.32 kg/m², mean MAP score was 0.69 ± 1.15, and mean operative time was 40.25 ± 9.81 minutes. Although mean BMI was higher in women (28.19 ± 4.52 vs 27.03 ± 4.07; P < .05), mean MAP score was lower than in men (0.35 ± 0.86 vs 1.03 ± 1.29; P < .001). Older age, higher BMI, higher MAP score, and presence of multiple renal arteries were associated with longer operative time of LDN. The MAP score was associated with older age, male sex and higher BMI.

CONCLUSIONS

This study showed that different risk factors can affect operative time in LDN. The MAP score was significantly associated with longer operative time, especially in men, so it can be useful for predicting surgical difficulty in kidney donors.

Nephrometry Scores: Can Preoperative Assessment of Sectional Imaging Really Mirror Intraoperative Renal Tumor Anatomy?

INTRODUCTION

To compare RENAL, preoperative aspects and dimensions used for an anatomical (PADUA) classification, and Mayo Adhesive Probability (MAP) scores with the respective intraoperative findings and surgeon's assessment in predicting surgical outcome of patients undergoing partial nephrectomy.

METHODS

Data of 150 eligible patients treated at the University Medical Center Mannheim between 2016 and 2018 were analyzed. Tumors were radiologically and intraoperatively assessed by PADUA, RENAL, and MAP scores and surgeon's assessment. Correlations and regression models were created to predict ischemia time (IT), major complications, and Trifecta (negative surgical margin, IT < 25 min, and absence of major complications).

RESULTS

There were strong correlations between radiological and intraoperative RENAL (r = 0.68; p < 0.001) and PADUA scores (r = 0.72; p < 0.001). Radiological RENAL, PADUA, and MAP scores and surgeon's assessment were independent predictors of Trifecta (OR = 0.71, p = 0.015; OR = 0.77, p = 0.035; OR = 0.65, p = 0.012; OR = 0.40, p = 0.005, respectively). IT showed significant associations with radiological RENAL, PADUA, and surgeon's assessment (OR = 1.41, p = 0.033; OR = 1.34, p = 0.044; OR = 3.04, p = 0.003, respectively). MAP score proved as only independent predictor of major complications (OR = 2.12, p = 0.002).

CONCLUSION

Radiologically and intraoperatively assessed scores correlated well with each other. Intraoperative nephrometry did not outperform radiological scores in predicting outcome confirming the value of the existing systems. MAP score correlates well with surgeon's assessment of perirenal fat and major complications underlining the importance of perirenal fat characteristics.

The clinical application value of mixed-reality-assisted surgical navigation for laparoscopic nephrectomy

Purpose

Laparoscopic nephrectomy (LN) has become the preferred method for renal cell carcinoma (RCC). Adequate preoperative assessment or intraoperative navigation is key to the successful implementation of LN. The aim of this study was to evaluate the clinical application value of mixed‐reality–assisted surgical navigation (MRASN) in LN.

Patients and Methods

A total of 100 patients with stage T1N0M0 renal tumors who underwent laparoscopic partial nephrectomy (LPN) or laparoscopic radical nephrectomy (LRN) were prospectively enrolled and divided into a mixed‐reality‐assisted laparoscopic nephrectomy (MRALN) group (n = 50) and a non–mixed‐reality‐assisted laparoscopic nephrectomy (non‐MRALN) group (n = 50). All patients underwent renal contrast‐enhanced CT scans. The CT DICOM data of all patients in the MRALN group were imported into the mixed‐reality (MR) postprocessing workstation and underwent holographic three‐dimensional visualization (V3D) modeling and MR displayed, respectively. We adopted the Likert scale to evaluate the clinical application value of MRASN. The consistency of evaluators was assessed using the Cohen kappa coefficient (k).

Results

No significant differences in patient demographic indicators between the MRALN group and the non‐MRALN group (P > .05). The subjective score of MRASN clinical application value in operative plan formulation, intraoperative navigation, remote consultation, teaching guidance, and doctor‐patient communication were higher in the MRASN group than in the non‐MRASN group (all P < .001). There were significantly more patients for whom LPN was successfully implemented in the MRALN group than in the non‐MRALN group (82% vs 46%, P < .001). The MRALN group had a shorter operative time (OT) and warm ischemia time (WIT) and less estimated blood loss (EBL) than the non‐MRALN group (all P < .001).

Conclusion

MRASN is helpful for operative plan formulation, intraoperative navigation, remote consultation, teaching guidance, and doctor‐patient communication. MRALN may effectively improve the successful implementation rate of LPN and reduce the OT, WIT, and EBL.

The Mayo Adhesive Probability Score Predicts Longer Dissection Time During Laparoscopic Partial Nephrectomy

Background: To examine the impact of the Mayo adhesive probability (MAP) score on the surgical complexity of exposing the tumor during laparoscopic partial nephrectomy (LPN). Patients and Methods: Our study included 318 patients who underwent LPN from January 2017 to December 2018 at our institution. Patients were divided into a lower MAP score group (≤2, n = 172) and a higher MAP score group (≥3, n = 146). Perioperative outcomes were compared between the groups. The operative time was predominantly occupied by the dissection time and the warm ischemia time (WIT). Results: A higher MAP score was associated with a longer operative time (131 vs 110 minutes, p < 0.001) and longer dissection time (71 vs 54 minutes, p < 0.001), respectively. The estimated blood loss (EBL) increased in patients with a higher MAP score (50 vs 20 mL, p < 0.001). No significant difference was found with respect to the WIT (21 vs 20 minutes, p = 0.370). In the multivariate linear regression model, male gender (β = 11.199, p = 0.001), body mass index (β = 1.197, p = 0.008), and MAP score (β = 9.958, p = 0.002) were significantly associated with the prolongation of dissection time. Conclusions: The MAP score was significantly associated with the prolongation of dissection time during LPN. In addition, the EBL increased in patients with a higher MAP score. Therefore, the MAP score can predict surgical complexity of exposing the tumor in patients undergoing LPN.

Prospective evaluation of the effect of adherent perinephric fat on outcomes of robotic assisted partial nephrectomy following elimination of the learning curve

PURPOSE

To prospectively evaluate the association of adherent perinephric fat (APF) on perioperative outcomes of robotic-assisted partial nephrectomy (RAPN) following elimination of the surgical learning curve.

MATERIALS AND METHODS

305 consecutive RAPNs performed by a single experienced surgeon were analyzed. The fi rst 100 RAPNs were considered the learning curve and therefore excluded. APF was defined as the necessity of subcapsular renal dissection to mobilize the tumor from surrounding perinephric fat. Perioperative outcomes were evaluated including operative time, warm ischemia time (WIT), postoperative complications, length of stay, margins, ischemia, and complications score (MIC), estimated blood loss (EBL), and change in pre-operative to postoperative day 1 (POD 1) laboratory values. After correction for multiple comparisons, P values ≤0.0045 were considered statistically signifi cant but associations with P values ≤0.05 were also mentioned in the study results.

RESULTS

Fifty-eight (28.3%) patients had APF. Patients with APF had longer operative times compared to those without APF (median, 213 vs. 192 minutes, P <0.001). There was some evidence of higher increase in change in creatinine from preoperative to POD 1 among those with APF compared to those without APF, although this was not statistically signifi cant (median, 0.2 vs. 0.1mg/dL, P=0.03). There were no other statistically significant associations between presence of APF and perioperative outcomes.

CONCLUSIONS

APF is associated with increased operative time but no change in other perioperative outcomes. Surgeon experience does not affect perioperative outcomes associated with APF.

Establishment of a novel system for the preoperative prediction of adherent perinephric fat (APF) occurrence based on a multi-mode and multi-parameter analysis of dual-energy CT

Background

Adherent perinephric fat (APF) is evaluated preoperatively with the Mayo adhesive probability (MAP) scoring system using conventional single-form computed tomography (CT) images. An objective or quantitative indicator for predicting APF is urgently needed for clinical application.

Methods

A total of 150 patients with renal tumours who underwent laparoscopic partial nephrectomy (LPN) were retrospectively enrolled and divided into the APF group (n=100) and the non-APF group (n=50) according to surgical results. All patients underwent a renal contrast-enhanced dual-energy CT (DECT) scan. The obtained CT DICOM data were transmitted to the DECT post-processing workstation and adopted virtual non-contrast (VNC), Rho/Z Maps, and Monoenergetic Plus (mono+) modes separately to undergo a multi-parameter analysis. A logistic stepwise investigation was utilized to analyse the related risk factors. The cutoff value was determined by the Youden index. Fifty patients were prospectively enrolled to validate the constructed model. The area under the curve (AUC), sensitivity, specificity and accuracy of the model were calculated.

Results

The study demonstrated that age, sex, body mass index (BMI), smoking status, tumour diameter, exophytic status, degree of malignancy and posterior perinephric fat thickness were related to the occurrence of APF (P<0.05). Model 1 was selected with the contrast material (CM) parameter (cutoff point 0.5), model 2 was selected with the effective atomic number (Z_eff) parameter (cutoff point 6.5), and model 3 was selected with the slope K (K) parameter (cutoff point -0.95). The AUC, sensitivity, specificity and accuracy of model 1 were 0.94, 0.94, 0.93 and 0.94, respectively; for model 2, they were 0.94, 0.93, 0.93 and 0.96, respectively; and for model 3, they were 0.92, 0.92, 0.93 and 0.92, respectively.

Conclusions

Multi-mode and multi-parameter models of DECT can effectively be used to predict the occurrence of APF.

Application value of dual-energy computed tomography spectrum curve combined with clinical risk factors in predicting adherent perinephric fat

Background

Adherent perinephric fat (APF) is evaluated preoperatively with the Mayo adhesive probability (MAP) scoring system using conventional single form computed tomography (CT) images. An objective or quantitative indicator for predicting APF is urgently needed for clinical application.

Methods

Data obtained from 150 renal tumor patients with partial nephrectomy (PN) were used in the present study. Patients were divided into two groups based on the surgical results: an APF group (n=100) and a non-APF group (n=50). All patients had renal contrast-enhanced dual-energy CT (DECT) scan, and the data were brought into a post-processing workstation. Monoenergetic plus mode was adopted to analyze the spectrum curve of the region of interest (ROI). Logistic stepwise relapse investigation was utilized to analyze the related risk factors. The maximum Youden index was taken as the cut-off value. The sensitivity, specificity, accuracy, and 95% CI of the model were calculated.

Results

APF is related to patients' clinical characteristics of age, gender, BMI, smoking, tumor diameter, exophytic, and benign or malignant nature of the renal masses (P<0.05). The shape of the curve of ROI₁ in the APF group was different from that of the ROI₄ in the non-APF group, and the curve slope of K1 (-0.21±0.47) was different from that of K4 (-1.30±0.14) (P<0.001). Statistical analysis showed that the slope K was solely retained in the model index. The best cut-off point for the K value was -0.95. The AUC of the cut-off point was 0.97 (95% CI: 0.96-0.99).

Conclusions

The DECT spectrum curve performed well in predicting APF, and the curve slope K can be used as an objective quantitative indicator.

Risk Factors Influencing the Thickness and Stranding of Perinephric Fat of Mayo Adhesive Probability Score in Minimally Invasive Nephrectomy

Background

Mayo adhesive probability (MAP) score, an accurate and reliable predictor of adherent perinephric fat (APF), consists of posterior perinephric fat thickness and perinephric fat stranding. The present study aimed to identify the potential clinical characteristics associated with these 2 variables to further our understanding of APF.

Material/Methods

Clinical data of 346 patients subjected to minimally invasive nephrectomy was collected within our prospectively maintained database, between January 2015 and December 2016. Radiological data was assessed by 2 readers in an independent blinded – to each other and APF patient status – fashion. Ordinal logistic regression analyses were performed to evaluate risk factors of posterior perinephric fat thickness and perinephric fat stranding.

Results

On multivariate analysis, posterior perinephric fat thickness was associated with older age (b=1.05 [range, 1.03–1.07], P<0.01); male gender (b=6.06 [3.18–11.54], P<0.01), and higher body mass index (BMI) (b=1.31 [1.21–1.41], P<0.01). Perinephric fat stranding was associated with older age (b=1.05 [1.02–1.07], P<0.01), male gender (b=3.64 [2.09–6.34], P<0.01) and history of diabetes (b=2.09 [1.24–3.52], P<0.01). MAP score was associated with older age (b=1.05 [1.03–1.07], P<0.01), male gender (b=5.07 [2.96–8.71], P<0.01), higher BMI (b=1.14 [1.07–1.21], P<0.01), history of diabetes (b=1.72 [1.06–2.78], P=0.03) and alcoholism (b=1.88 [1.10–3.20], P=0.02).

Conclusions

The current study highlights that different risk factors influence the posterior perinephric fat thickness and perinephric fat stranding. Posterior perinephric fat thickness was correlated with age, gender, and BMI, while perinephric fat stranding was associated with age, gender, and history of diabetes.