Mayo Adhesive Probability Score Is an Independent Computed Tomography Scan Predictor of Adherent Perinephric Fat in Open Partial Nephrectomy

Is the Mayo adhesive probability score predictive of post-operative Clavien-Dindo complication grade in laparoscopic adrenalectomy?

INTRODUCTION

Laparoscopic adrenalectomy (LA) continues to be considered the optimum approach to the surgical treatment of small benign adrenal tumours. The present study explores the correlation between the Mayo adhesive probability (MAP) score, derived from computed tomography images and delineating such perinephric fat characteristics as thickness and adhesiveness, and post-operative complications in patients undergoing LA.

PATIENTS AND METHODS

Data of patients who underwent LA between 2013 and 2023 were subjected to a retrospective analysis, and MAP scores were calculated for all patients. Intraoperative and post-operative surgical outcomes, as well as any complications, were categorised using Modified Clavien-Dindo grading, and the relationship between their MAP scores and outcomes was analysed.

RESULTS

The mean body mass index, rate of overweight patients, Clavien-Dindo scores of II, III or IV, surgical time, hospitalisation duration, transfusion requirement and post-operative blood loss of the group of patients with MAP scores of 2-3 were significantly higher than those in the group with MAP scores in the 0-1 range (P < 0.05). Each one-point increase in MAP score led to a 2.559-times greater probability of a Clavien-Dindo Grade > I (95% confidence interval: 1.391-4.708, P < 0.05).

CONCLUSION

A high MAP score is associated with Grade II and higher Clavien-Dindo complications in LA.

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.

Predicting the presence of adherent perinephric fat using MRI radiomics combined with machine learning

OBJECTIVES

Adherent perinephric fat (APF) poses significant challenges to surgical procedures. This study aimed to evaluate the usefulness of machine learning algorithms combined with MRI-based radiomics features for predicting the presence of APF.

MATERIALS AND METHODS

Patients with renal cell carcinoma who underwent surgery between April 2019 and February 2022 at Chonnam National University Hwasun Hospital were retrospectively screened, and 119 patients included. Twenty-one and seventeen patients were set aside for the internal and external test sets, respectively. Pre-operative T1-weighted MRI acquired at 60 s following a contrast injection (T1w-60) were collected. For each T1w-60 data, two regions of interest (ROIs) were manually drawn: the perinephric fat tissue and an aorta segment on the same level as the targeted kidney. Preprocessing steps included resizing voxels, N4 Bias Correction filtering, and aorta-based normalization. For each patient, 851 radiomics features were extracted from the ROI of perinephric fat tissue. Gender and BMI were added as clinical factors. Least Absolute Shrinkage and Selection Operator was adopted for feature selection. We trained and evaluated five models using a 4-fold cross validation. The final model was chosen based on the highest mean AUC across four folds. The performance of the final model was evaluated on the internal and external test sets.

RESULTS

A total of 15 features were selected in the final set. The final model achieved the accuracy, sensitivity, specificity, and AUC of 81% (95% confidence interval, 61.9-95.2%), 72.7% (42.9-100%), 90% (66.7-100%), and 0.855 (0.615-1.0), respectively on the internal test set, and 88.2% (70.6-100%), 100% (100-100%), 80% (50%-100%), 0.971 (0.871-1.0), respectively on the external test set.

CONCLUSIONS

Our study demonstrated the feasibility of machine learning algorithms trained with MRI-based radiomics features for APF prediction. Further studies with a multi-center approach are necessary to validate our findings.

The mayo adhesive probability score predicts postoperative fever and sepsis in retrograde intrarenal surgery

Infectious complications are among the most common and potentially life-threatening morbidities of retrograde intrarenal surgery (RIRS). Few predictive tools on these complications include radiological signs. The Mayo adhesive probability (MAP) score is an image-based scoring system that incorporates two radiological signs: perinephric fat stranding and perinephric fat thickness. Previous studies have suggested an association between these signs and febrile urinary tract infection (UTI) following lithotripsy. This study aimed to evaluate the predictive factors, including the MAP score, for post-RIRS fever and sepsis. A total of 260 patients who underwent 306 RIRS between October 2019 to December 2023 due to renal or upper ureteral stones were included in this retrospective study. Patient demographics, perioperative characteristics, stone factors, radiological signs, and MAP scores were recorded. Multivariate logistic regression analysis was used to evaluate the risk factors associated with postoperative fever and sepsis. Postoperative fever and sepsis occurred in 20.8% and 8.5% of the patients, respectively. On multivariate analysis, female gender, history of recurrent UTI, larger maximal stone diameter, and higher MAP score were independent risk factors for postoperative fever and sepsis. Identifying the risk factors for post-RIRS infectious complications is imperative to providing the proper perioperative management. The MAP score is a promising, easily calculated, image-based scoring system that predicts post-RIRS fever and sepsis.

Predictive Value of the Mayo Adhesive Probability (MAP) Score in Laparoscopic Partial Nephrectomies: A Systematic Review from the EAU Section of Uro-Technology (ESUT)

The Mayo Adhesive Probability (MAP) score is a radiographic scoring system that predicts the presence of adherent perinephric fat (APF) during partial nephrectomies (PNs). The purpose of this systematic review is to summarize the current literature on the application of the MAP score for predicting intraoperative difficulties related to APF and complications in laparoscopic PNs. Three databases, PubMed, Scopus and Cochrane, were screened, from inception to 29 October 2023, taking into consideration the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Guidelines. All the inclusion criteria were met by eight studies. The total operative time was around two hours in most studies, while the warm ischemia time was <30 min in all studies and <20 min in four studies. Positive surgical margins, conversion and transfusion rates ranged from 0% to 6.3%, from 0% to 5.0% and from 0.7% to 7.5%, respectively. Finally, the majority of the complications were classified as Grade I-II, according to the Clavien-Dindo Classification System. The MAP score is a useful tool for predicting not only the presence of APF during laparoscopic PNs but also various intraoperative and postoperative characteristics. It was found to be significantly associated with an increased operative time, estimated blood loss and intraoperative and postoperative complication rates.

Impact of perinephric fat volume and the Mayo Adhesive Probability score on time to clamping in robot-assisted partial nephrectomy

The aim of this study is to evaluate the association of perinephric fat volume (PNFV) and the Mayo Adhesive Probability (MAP) score with time to clamping (TTC) in robot-assisted partial nephrectomy (RAPN). The study subjects consisted of 73 tumors in 72 patients who underwent transperitoneal RAPN at a single cancer center between February 2020 and July 2022. Clinical characteristics including R.E.N.A.L. nephrometry score, MAP score and PNFV were evaluated in a multivariate analysis in relation to TTC, which was classified into two groups based on median TTC. PNFV and MAP score were analyzed separately. PNFVs were measured by SYNAPSE VINCENT® by a single expert urologist. Median TTC was 67 (range: 36-119) min. Spearman's rank correlation analysis indicated that a significant correlation was observed between PNFV and MAP score with a value of 0.81 (p < 0.0001). Univariate analysis revealed that R.E.N.A.L. nephrometry score ≥ 7 (p = 0.036), posterior tumor location (p = 0.033), MAP score ≥ 3 (p = 0.02) and PNFV ≥ 250 ml (p = 0.02) were significant factors for prolonged TTC. In a multivariate analysis including PNFV (analysis 1), R.E.N.A.L. nephrometry score ≥ 7 (OR 3.54, p = 0.018) and PNFV ≥ 250cm3 (OR 3.94, p = 0.010) were independent factors for prolonged TTC. Similarly for MAP score (analysis 2), R.E.N.A.L. nephrometry score ≥ 7 (OR 3.54, p = 0.018) and MAP score ≥ 3 (OR 3.94, p = 0.010) were independent factors for prolonged TTC. Both MAP score and PNFV may have a significant impact on TTC.

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.

Comparison of perinephric fat measurements between malignant and benign renal tumours

Objective

To investigate different parameters derived from the quantity and quality of perinephric fat, and to compare their effectiveness in predicting the malignant pathology of renal tumours.

Methods

Data from patients diagnosed with renal tumour between April 2014 and December 2020 were retrospectively reviewed, and patients were categorized into malignant or benign tumour groups. Fat parameters, including perinephric fat volume (PFV), perinephric fat area (PFA), perinephric fat thickness (PFT), and Mayo adhesive probability (MAP) score were measured using abdominal computed tomography scans. Between-group differences were assessed by analysis of variance and χ²-test. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the performance of perinephric fat parameters in diagnosing malignancy.

Results

A total of 109 patients were included. MAP score, PFV, PFA, and PFT were significantly increased in the malignant versus benign tumour group, and after correction for body mass index (BMI), the indexed PFV/BMI, PFA/BMI, and PFT/BMI values remained significantly higher in the malignant tumour group. All parameters showed fair predictivity of malignancy, with comparable area under the curve values in the ROC curve.

Conclusion

An increased amount of perinephric fat is predictive of malignant pathology for renal tumours. The predictive accuracy for each perinephric fat parameter remained fair after correcting for BMI.

Analysis of Clinical Characteristics, Radiological Predictors, Pathological Features, and Perioperative Outcomes Associated with Perinephric Fat Adhesion Degree

Background

To assess the clinical characteristics, radiological predictors, and pathological features of perinephric fat adhesion degree (PFAD) graded based on fixed criteria and to determine the impact of adherent perinephric fat (APF) on retroperitoneal laparoscopic partial nephrectomy (RLPN) outcomes.

Methods

84 patients undergoing RLPN were included and graded into 4 groups based on PFAD. Univariate and multivariate analyses were performed for clinical characteristics and radiological predictors of PFAD. Perioperative data were compared between APF groups and non-APF groups. Masson staining determined collagen fibers. Immunohistochemistry detected CD45 immune cells and CD34 vessels.

Results

20, 28, 18, and 18 patients were graded as normal perinephric fat (NPF), mild adherent perinephric fat (MiPF), moderate adherent perinephric fat (MoPF), and severe adherent perinephric fat (SPF), respectively. Multivariate analysis revealed that gender (p < 0.001), age (p = 0.003), and hypertension (p = 0.006) were significant clinical risk factors of PFAD, while radiological predictors included perinephric stranding (p = 0.001), posterior perinephric fat thickness (p = 0.009), and perinephric fat density (p = 0.02). APF was associated with drain output (p = 0.012) and accompanied by immune cells gathering in renal cortex near thickened renal capsule with many vessels.

Conclusions

Clinical characteristics and radiological predictors can evaluate PFAD and may assist to guide preoperative surgical option. Pathological features of APF reflect decapsulation and bleeding during kidney mobilization at RLPN.

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.

Study on the correlation between preoperative inflammatory indexes and adhesional perinephric fat before laparoscopic partial nephrectomy

Objective

This study was aimed to evaluate the effect of preoperative composite inflammatory index on adhesional perinephric fat (APF), providing a help for preoperative risk assessment of laparoscopic partial nephrectomy (LPN) in patients with renal cell carcinoma.

Materials and methods

A retrospective study was conducted on 231 patients with renal cell carcinoma, who underwent laparoscopic partial nephrectomy. They were divided into two groups according to whether there was APF during operation. Relevant clinical data, laboratory parameters and imaging examination were obtained before operation to calculate the composite inflammatory index and MAP score. The composite inflammatory index was divided into high value group and low value group by ROC curve method. The related predictive factors of APF were analyzed by logistic regression method.

Results

The APF was found in 105 patients (45.5%). In multivariate analysis, systemic immune inflammation index (SII) (high/low), MAP score, tumor size and perirenal fat thickness were independent predictors of APF. The operation time of patients with APF was longer, and the difference of blood loss was not statistically significant.

Conclusion

SII is an independent predictor of APF before laparoscopic partial nephrectomy.

Trial registration ChiCTR, ChiCTR2100045944. Registered 30 April 2021—Retrospectively registered, http://www.chictr.org.cn/showproj.aspx?proj=125703.

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.

Usefulness of the mayo adhesive probability score as a predictive factor for renal function deterioration after partial nephrectomy: a retrospective case-control study

PURPOSE

Whether the Mayo adhesive probability score, an index of the perinephric fat environment, could be a predictive factor for renal function deterioration after partial nephrectomy was investigated.

METHODS

A retrospective case-control study of 78 patients who underwent laparoscopic partial nephrectomy was performed. An estimated glomerular filtration rate preservation rate at ≤ 90% at 3 months after surgery was defined as postoperative renal function deterioration. These patients were divided into two groups (non-deterioration and deterioration groups). Patient factors including Mayo adhesive probability scores (both tumor and unaffected sides) and surgical factors were evaluated to identify the predictors for postoperative renal function deterioration. The statistical analysis used univariate and multivariate logistic regression analyses.

RESULTS

Thirty-seven (47.4%) patients had postoperative renal function deterioration after partial nephrectomy. Univariate analysis identified Mayo adhesive probability score on the unaffected side (p = 0.02), and warm ischemia time (p < 0.01) as predictors of postoperative renal function deterioration. On multivariate analyses, Mayo adhesive probability score on the unaffected side (odds ratio: 1.38 [1.05-1.79], p = 0.02) and warm ischemia time (odds ratio: 1.04 [1.01-1.07], p < 0.01) were significantly associated with postoperative renal function deterioration as same as univariate analysis. On receive operating characteristic curve analysis, Mayo adhesive probability score on the unaffected side (cutoff value 1.5; p = 0.02) and warm ischemia time (cutoff value 26.5 min; p = 0.01) were significant predictors of renal function deterioration 3 month after surgery.

CONCLUSION

The Mayo adhesive probability score on the unaffected side and warm ischemia time are useful predictors for renal function deterioration after partial nephrectomy.

TRIAL REGISTRATION NUMBER

2019-249, January 21st, 2019, retrospectively registered.

Mayo Adhesive Probability Score Is Associated with the Operative Time in Laparoscopic Adrenalectomy

Background: Laparoscopic adrenalectomy (LA) is the standard treatment for adrenal benign tumors, including primary aldosteronism (PA) or Cushing's syndrome (CS). Several obesity-related factors were associated with prolonged total operative time (OT), but perinephric fat characteristics were not assessed. We investigated whether the Mayo adhesive probability (MAP) score, which evaluates perinephric fat characteristics, was associated with OT for LA. Methods: This single-center, retrospective cohort study examined 141 consecutive patients who underwent LA for PA or CS. We reviewed patients' characteristics and OT. MAP scores were recorded using preoperative imaging. The correlation among characteristics data, MAP score, and OT was evaluated. Results: Overall, we assessed 82 women and 59 men. Adrenal tumors were found in 80 PA and 61 CS patients. There were 74 left-sided and 67 right-sided tumors. For all patients, the median age, body mass index, and tumor size were 56 years (interquartile range [IQR] 46-65), 24.1 kg/m² (IQR 21.7-26.8), and 19 mm (IQR 13-26), respectively. A total of 91 patients had MAP scores of 0, and 50 had MAP >0. The median OT was 183.5 minutes (IQR: 156-224 minutes) in the MAP >0 group and 162 minutes (IQR: 135-194 minutes) in the MAP = 0 group. In single variable analysis (unadjusted), MAP scores >0 and left-sided tumors were correlated with longer OT. Multivariable regression analysis revealed that this correlation was only significant for MAP scores >0. Conclusions: MAP score may be useful in preoperative planning for PA or CS patients undergoing LA.

Impact of the Mayo Adhesive Probability Score on Donor and Recipient Outcomes After Living-donor Kidney Transplantation: A Retrospective, Single-center Study of 782 Transplants

Supplemental Digital Content is available in the text.

Background.

This study was performed to assess the impact of the Mayo Adhesive Probability (MAP) score on donor and recipient outcomes after living-donor kidney transplantation (LDKT).

Methods.

We retrospectively analyzed 782 transplants involving LDKT between February 2008 and October 2019 to assess the correlation between the MAP score and outcome after LDKT. We divided the transplants into 2 groups according to the donor MAP score: 0 (MAP₀) and 1–5 (MAP_1–5).

Results.

Compared with the MAP₀ group, donors in the MAP_1–5 group were significantly older, had higher body mass index, and were more likely to be men. The prevalences of hypertension, hyperlipidemia, and diabetes were also higher among donors in the MAP_1–5 group than among donors in the MAP₀ group. Operative time, estimated blood loss during donor nephrectomy, and percentage of glomerular sclerosis were significantly greater in the MAP_1–5 group than in the MAP₀ group. Donor and recipient perioperative complications were comparable between the 2 groups; death-censored graft survival rates also did not significantly differ between groups. Although the recipient mean estimated glomerular filtration rate (eGFR) from postoperative d 1 to 7 was significantly higher in the MAP₀ group than in the MAP_1–5 group (P = 0.007), eGFR reductions within 5 y after transplantation were similar between groups. There were no significant differences between groups in recipient mortality and biopsy-proven acute rejection episodes within 1 y after transplantation. Additionally, multivariate analysis showed that the only factors affecting recipient eGFR at postoperative d 7 were donor age, recipient age, and female sex (P < 0.001, <0.001, and =0.004, respectively).

Conclusions.

The MAP score did not influence surgical complications or graft survival; therefore, it should not affect donor selection.

Assessment of Patient-Related Operative Complexity During Partial Nephrectomy: Comparison of Two Tailored Methods for Measurement of Posterior Perinephric Fat Thickness on Preoperative CT

Background: Adherent perinephric fat affects operative complexity during partial nephrectomy (PN) and it could be predicted using computed tomography (CT) based on the Mayo adhesive probability (MAP) score. Objectives: To investigate reproducible measurement methods of perinephric fat with comparison of two tailored methods for measurement of posterior perinephric fat thickness (PPFT) on preoperative CT and examine the association between the methods and operative complexity in PN. Patients and Methods: This cross-sectional study included 72 consecutive patients who underwent robotic-assisted or open PN. The data on operative time, ischemia time, and pathologic results were obtained. Two radiologists independently assessed PPFT based on the MAP system in the first session, and subsequently by using two tailored methods in the second session and scored for perinephric fat stranding. The nephrometry scoring system was used for stratifying the complexity of renal masses. Multiple linear regression was used to evaluate the determinants of operative time and ischemia time. Results: For measurement of PPFT, intraclass correlation coefficients between the reviewers using two detailed methods showed no statistical difference (P = 0.173) but were significantly higher than the coefficients scored in the first session (P < 0.001). Nephrometry score was a determinant of ischemia time (P < 0.001 and 0.001 for two reviewers) and PPFT was identified as a determinant of operative time (P ≤ 0.023 in all the analysis using two different methods for both the reviewers) in robotic-assisted PN. Nephrometry score was identified as a determinant of ischemia time in open PN as per one of the reviewers (P = 0.006). Conclusion: The tailored methods presented herein were more reproducible than the MAP score and demonstrated that increased PPFT was related to longer operative time in robotic-assisted, and not in open PN.

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.

Mayo Adhesive Probability (MAP) score of non-donated kidney aids in predicting post-operative renal function following donor nephrectomy

Background

To examine the association of preoperative Mayo Adhesive Probability (MAP) scores in the donor (MAP_d) and non-donor kidneys (MAP_nd) with post-donation renal function.

Methods

Three hundred thirty-one patients undergoing hand assisted laparoscopic donor nephrectomy (HALDN) were reviewed. MAP_d and MAP_nd were obtained. Estimated glomerular filtration rate (eGFR) was recorded preoperatively and at 1 day, 1 month, and 6 months postoperatively.

Results

Two hundred females and 131 males were evaluated with median BMI 26.4 kg/m² (range 17.1–39.6) and median age 45 years (range 19–78). MAP_d score was 0 for 231 patients (69.8%) and > 0 for 100 patients (30.2%). MAP_nd score was 0 for 234 patients (70.7%) and > 0 for 97 patients (29.3%). The median preoperative eGFR was 86.6 ml/min/1.73m² (range 48.8–138.4). After adjusting for preoperative eGFR, BMI, ASA score, and kidney sidedness, postoperative eGFR was associated with MAP score in the non-donated kidney (p = 0.014) but not in the donated kidney (p = 0.24). Compared to donors with MAP_nd = 0, donors with a MAP_nd > 0, mean eGFR was − 2.33 ml/min/1.73m² lower at postoperative day 1 (95% CI − 4.24 to − 0.41, p = 0.018), − 3.02 ml/min/1.73m² lower at 1 month (95% CI − 5.11 to − 0.93, p = 0.005), and − 2.63 ml/min/1.73m² lower at 6 months postoperatively (95% CI − 5.01 to − 0.26, p = 0.030).

Conclusions

MAP score > 0 in the non-donated kidney is associated with worse renal function in the 6 months following HALDN.

A novel nephrometry scoring system for predicting peri-operative outcomes of retroperitoneal laparoscopic partial nephrectomy

BACKGROUND

Although the impact of tumor complexity on peri-operative outcomes has been well established using several nephrometry scoring systems, the impact of adherent perirenal fat remains poorly defined. This study aimed to develop a novel nephrometry scoring system for predicting the peri-operative outcomes of laparoscopic partial nephrectomy (LPN) by integrating and optimizing the RENAL score (RNS) and Mayo adhesive probability (MAP) score.

METHODS

We retrospectively evaluated 159 patients treated with retroperitoneal LPN. The patients' demographic parameters, RNSs, and MAP scores were evaluated as potential predictors of perioperative outcomes, including operation time, estimated blood loss (EBL), and margin, ischemia, and complication (MIC) achievement rate. The independent predictors were used to develop a novel nephrometry scoring system. The predictive value and inter-observer agreement for the novel nephrometry scoring system were evaluated.

RESULTS

Tumor radius (R score), nearness to the renal sinus or collecting system (N score), and posterior perinephric fat thickness were independent predictors of peri-operative outcomes and were used to develop the RNP score. The univariate analysis revealed that the RNP score was significantly associated with operation time, EBL, and MIC achievement rate (P < 0.050). The RNP score was an independent predictor of operation time (P < 0.001), EBL (P = 0.018), and MIC achievement rate (P = 0.023) in the multivariate analysis. The RNP score was not inferior to RNS in the area under the curve for predicting peri-operative outcomes and performed better in inter-observer agreement (76.7% vs. 57.8%) and kappa value (0.804 vs. 0.726).

CONCLUSION

The RNP score, combining the advantages of the RNS and MAP score, demonstrated a good predictive value for the peri-operative outcomes of retroperitoneal LPN and better inter-observer agreement.

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.

Adherent Perinephric Fat Is a Surgical Risk Factor in Laparoscopic Single-Site Donor Nephrectomy: Analysis Using Mayo Adhesive Probability Score

BACKGROUND

The host-related risk factors for surgical difficulty of partial nephrectomy include the presence of thick and adherent adipose tissue surrounding the kidney (adherent perinephric fat [APF]). The kidney and perirenal fat must be isolated in donor nephrectomy. Thus, APF is an important surgery-related factor. We analyzed whether the Mayo adhesive probability (MAP) score is related to APF and surgical outcomes in laparoscopic single-site donor nephrectomy (LESS-DN).

METHODS

Forty-six donors who underwent LESS-DN were selected. Determination of APF was based on a retrospective review of video-recorded surgical procedures during anterior perinephric fat dissection. The MAP score was evaluated from computed tomography images. Data regarding patient characteristics and operative outcomes were collected. We then examined the MAP score, APF, and related factors.

RESULTS

Eleven patients (23.9%) had APF. The patients were divided into 2 groups (MAP score of 0 points and ≥ 1 point). The 2 groups showed significant differences in sex, age, body mass index, history of hypertension, and history of dyslipidemia. The operation time was significantly longer and the estimated blood loss volume was higher in patients with a MAP score of ≥ 1. Eight of 9 patients with a MAP score of ≥ 1 had APF. The only significant differences between patients with and without APF were in the body mass index, history of hypertension, and history of dyslipidemia. The operation time was significantly longer and the estimated blood loss volume was larger in patients with APF.

CONCLUSIONS

The MAP score could be useful when predicting surgical difficulty in patients undergoing LESS-DN.

Significant impact of three-dimensional volumetry of perinephric fat on the console time during robot-assisted partial nephrectomy

Background

To assess the impact of volumetry of perinephric fat (PNF) on the perioperative outcomes of robot-assisted partial nephrectomy (RAPN).

Methods

Between 2016 and 2019, a single surgeon performed RAPN for 128 patients with clinical T1a-b renal tumors at our institution, and the 70 most recent patients were included in this study to minimize the effects of surgical experience. PNF was defined as a fatty area around the kidney within the anatomical structures, including the lateroconal fascia, fusion fascia, psoas muscle, lumbar quadrate muscle and diaphragm, and its volume was calculated based on reconstructed three-dimensional computed tomography images using the SYNAPSE VINCENT system.

Results

In this series, the trifecta and MIC (margin, ischemia and complications) score system outcomes were achieved in 69 (98.6%) and 64 patients (91.4%), respectively. The median PNF volume in the 70 patients was 166.05 cm³, which was significantly correlated with both the body mass index (BMI) and Mayo adhesive probability (MAP) score (correlation coefficient = 0.68 and 0.74, respectively). There was no significant difference in the R.E.N.A.L. nephrometry score, PNF volume or console time during RAPN among 5 groups consisting of 14 consecutive patients. Of several factors examined, the console time was significantly affected by the sex, MAP score and PNF volume, and only the PNF volume was independently associated with the console time.

Conclusion

Even if performed by an experienced robotic surgeon beyond the initial learning curve, the PNF volume may influence the console time during RAPN.

Predictive Value of Nephrometry Scores in Nephron-sparing Surgery: A Systematic Review and Meta-analysis

CONTEXT

Over the last decade, several nephrometry scores (NSs) have been introduced with the aim of facilitating preoperative decision making, planning, and counseling in the field of nephron-sparing surgery. However, their predictive role remains controversial.

OBJECTIVE

To describe currently available nephrometry scores and to determine their predictive role for different outcomes by performing a systematic review and meta-analysis of the literature.

EVIDENCE ACQUISITION

PubMed, Embase®, and Web of Science were screened to identify eligible studies. Identification and selection of the reports were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). A pooled analysis of NS predictive role of intraoperative, postoperative, oncological, and functional outcomes was performed. Odds ratio was considered the effect size. All the analyses were performed using Stata 15.0, and statistical significance was set at p≤ 0.05.

EVIDENCE SYNTHESIS

Overall, 51 studies meeting our inclusion criteria were identified and considered for the analysis. Except for one prospective randomized trial, all the studies were retrospective. All the studies were found to be of intermediate quality, except for one of high quality. Most studies assessed the predictive role of the Radius-Exophytic/Endophytic-Nearness-Anterior/Posterior-Location (RENAL) and Preoperative Aspects and Dimensions Used for an Anatomical (PADUA) scores, mostly regarding complications after nephron-sparing surgery. RENAL was an independent predictor of an on-clamp procedure (p< 0.001). Mayo Adhesive Probability score was related to adhesive perinephric fat (p= 0.005). Continuous and high-complexity RENAL scores were predictors of warm ischemia time (WIT; p= 0.006 and p< 0.001, respectively). Continuous (p< 0.001) and high-complexity (p< 0.001) PADUA scores were related to WIT. Continuous and high-complexity RENAL scores were predictors of overall complications (p= 0.002 and p< 0.001, respectively). PADUA score was related to complications both as continuous (p< 0.001) and as a categorical value (p< 0.002). The RENAL scores R=3 (p= 0.008), E=2 (p= 0.039), and hilar location (p= 0.006) were predictors of histological malignancy. Continuous and categorical RENAL scores were independent predictors of an estimated glomerular filtration rate (eGFR) increase (p= 0.006 and p< 0.001, respectively). The Diameter-Axial-Polar score (p= 0.018) and Peritumoral Artery Scoring System (PASS; p= 0.02) were also independent predictors.

CONCLUSIONS

The literature regarding nephrometry scoring systems is sparse, and mostly focused on RENAL and PADUA, which are easy to calculate and have a good correlation with most outcomes. Renal Pelvic Score is the best predictor of pelvicalyceal entry/repair and urine leak, whereas Surgical Approach Renal Ranking and PASS strongly predict surgical approach and renal function variation, respectively. Other nephrometry scores based on mathematical models are limited by their complexity, and they lack evidence supporting their predictive value.

PATIENT SUMMARY

We reviewed the medical literature regarding the use and value of so-called "nephrometry scores," which are scoring systems based on radiological imaging and made to grade the complexity of a renal tumor. We analyzed whether these scoring systems can predict some of the outcomes of patients undergoing surgical removal of renal tumors.

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.

A comparison of perinephric fat surface area and Mayo Adhesive Probability score in predicting malignancy in T1 renal masses

INTRODUCTION

Recent studies have proposed that nearby fat deposits may have metabolic influence on kidney cancer pathobiology. Both fat quantity and quality may play unique roles in this complex relationship. As such, we investigated whether perinephric fat surface area (PFA), a quantitative measure of fat, or Mayo Adhesive Probability (MAP) score, a qualitative measure, were predictive of malignant pathology or Fuhrman grade in small renal masses.

METHODS

A total of 317 patients undergoing minimally invasive partial nephrectomy between 2010 and 2016 for renal masses were retrospectively reviewed. Preoperative abdominal CT and MRI scans were measured for PFA and MAP scores. Multiple binary logistic regression models were created to identify predictive factors of malignant disease and Fuhrman grade.

RESULTS

A total of 253 patients had malignant masses, while 64 had benign masses. A total of 189 of the malignant masses were T1a, while 64 were designated T1b. A total of 221 patients with malignant masses had reported Fuhrman grades. Of these 211 patients, 143 (64.7%) had low-grade and 78 (35.3%) had high-grade disease. Mean PFA was 18.0 ± 13.3 cm², while mean MAP score was 2.6 ± 1.2. Binary logistic regression analysis yielded three variables in the best-fit model for predictors of malignant pathology: MAP score (OR = 1.374, 95% CI: 1.007-1.873, P = 0.045), male sex (OR = 2.058, 95% CI: 1.004-4.218, P = 0.049), and BMI (OR = 1.064, 95% CI: 0.998-1.135, P = 0.059). Neither MAP nor PFA was predictive of Fuhrman grade.

CONCLUSIONS

MAP score, a measure of perinephric fat quality, but not PFA, a qualitative measure of fat quantity, was predictive of malignant pathology, raising the question whether fat quality rather than quantity may be involved in the pathophysiology of RCC in a large and diverse patient population. Understanding the increasing burden of obesity, further studies are needed to elaborate on these findings and to discern the exact relationship between perinephric fat deposits and renal tumorigenesis.

Analysis of Factors Influencing Mayo Adhesive Probability Score in Partial Nephrectomy

Background

To retrospectively explore the factors influencing Mayo Adhesive Probability (MAP) score in the setting of partial nephrectomy.

Material/Methods

Data of 93 consecutive patients who underwent laparoscopic and open partial nephrectomy from September 2015 to June 2016 were collected and analyzed retrospectively. Preoperative radiological elements were independently assessed by 2 readers. Ordinal logistic regression analyses were performed to evaluate radiological and clinicopathologic influencing factors of MAP score.

Results

On univariate analysis, MAP score was associated with male sex, older age, higher body mass index (BMI), history of hypertension and diabetes mellitus, and perirenal fat thickness (posterolateral, lateral, anterior, anterolateral, and medial). On multivariate analysis, only posterolateral perirenal fat thickness (odds ratio [OR]=0.88 [0.82–0.95], p=0.001), medial perirenal fat thickness (OR=0.90 [0.83–0.98], p=0.01), and history of diabetes mellitus (OR=5.42 [1.74–16.86], p=0.004) remained statistically significant. Tumor type (malignant vs. benign) was not statistically different. In patients with renal cell carcinoma (RCC), there was no difference in tumor stage or grade.

Conclusions

MAP score is significantly correlated with some preoperative factors such as posterolateral and medial perirenal fat thickness and diabetes mellitus. A new radioclinical scoring system including these patient-specific factors may become a better predictive tool than MAP score alone.

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

OBJECTIVE

Current guidelines recommend partial nephrectomy for the management of T1a tumours. Adherent perinephric fat (APF) has been recognized as a complicating feature of such surgery. The objective of this article was to present a systematic review of the published literature investigating APF aetiology, risk factors and outcomes.

MATERIALS AND METHODS

To identify relevant studies, the PubMed, MEDLINE, Web of Science and Google Scholar databases were searched from 1990 to 2017.

RESULTS

Eight studies studying APF were identified. The aetiology of APF appears to be multifactorial, but is thought to be associated with a systemic, chronic inflammatory state secondary to metabolic syndrome. Several risk factors have been identified. Clinically, APF is more prevalent in ageing and male populations, particularly those with high body mass index and waist measurements. Radiological risk factors for APF include increased perinephric fat thickness and stranding, which can be combined to produce the Mayo Adhesive Probability (MAP) score, a predictive index that has been validated in small, external cohorts. The presence of APF at partial nephrectomy is associated with increased operative time and estimated blood loss. However, there is no documented increase in warm ischaemia time or perioperative complications in patients with APF.

CONCLUSIONS

More studies are required to identify outcomes and risk factors for APF. Early identification of patients with APF can allow surgeons to guide preoperative planning and patient assessment.