Metabolic insights and novel risk score for adherent perinephric fat in partial nephrectomy: results from a prospective study

PURPOSE: This study aimed to identify preoperative metabolic and radiological predictors of adherent perinephric fat (APF) and to develop a predictive scoring system for its assessment. METHODS: We conducted a prospective study of consecutive patients with renal tumors undergoing open or minimally invasive partial nephrectomy (PN). APF was intraoperatively defined as the need for subcapsular renal dissection to isolate the tumor. Patient characteristics were compared according to APF presence. Multivariable logistic regression analysis was performed, and the resulting model was used to develop a predictive scoring system. RESULTS: A total of 200 patients were included in the analysis, of whom 34 (17%) had APF. On multivariable analysis, presence of perinephric fat stranding (p = 0.003), posterior perinephric fat thickness ≥ 25 mm (p < 0.001), serum urea ≥ 33 mg/dl (p = 0.004), albumin ≤ 4.3 g/dl (p = 0.007), and HDL cholesterol ≤ 53 mg/dl (p = 0.019) were predictors of APF. A model incorporating these five variables achieved an area under the receiver operating characteristic curve of 0.92. These parameters were subsequently integrated into the novel SHARP-U (Stranding, HDL cholesterol, Albumin, Renal Perinephric fat thickness, Urea) score, ranging from 0 to 7, to predict the presence of APF. CONCLUSION: The SHARP-U score provides a simple and reliable tool for preoperative prediction of APF in patients undergoing partial nephrectomy. Early identification of individuals at risk may aid surgical planning and patient counseling. External prospective validation of the SHARP-U score is warranted to confirm its clinical applicability.