Haifler M, et al. - This trial entailed the external validation of a mathematical formula for the tumor contact surface area (CSA) as a predictor of post-operative renal function, in patients undergoing partial nephrectomy for renal cell carcinoma. An association was revealed between CSA with a change in the post-operative renal function after partial nephrectomy. It could be utilized alongside the nephrometry score (NS), in order to counsel patients regarding their risk for a renal functional decline following partial nephrectomy.