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.