Abstract Background Despite partial nephrectomy (PN) renal function preservation benefits, postoperative renal dysfunction may occur. Perirenal fat thickness (PFT) is associated with renal dysfunction such as diabetes; however, its role in renal tumour surgery is unclear. This study investigates the role of PFT in renal function after robot‐assisted partial nephrectomy (RAPN). Methods Pre‐operative factors for postoperative renal dysfunction were analysed in 156 patients undergoing RAPN with ≥1‐year follow‐up. PFT measured using computed tomography categorised patients with PFT &gt;21.0 mm (median) as high‐PFT. Results Tumour size, total R.E.N.A.L. nephrometry score and its N component, renal calyx opening, achievement of trifecta, and PFT were risk factors for renal dysfunction 1 year postoperatively. Age ≥75 years ( p = 0.024), total RNS ≥7 ( p = 0.036), and PFT &gt;21.0 mm ( p = 0.002) significantly correlated with postoperative renal dysfunction. Conclusions CT‐measured PFT is a valuable predictor of postoperative renal dysfunction.

Effects of perirenal fat thickness on postoperative renal dysfunction in patients who underwent robot‐assisted partial nephrectomy for renal tumours