Porpiglia et al investigated renal function loss in 54 patients after laparoscopic partial nephrectomy for tumour and reported their findings in Eur Urol (2012). Loss, judged by a number of different techniques, occurred in the first 3 months and was stable afterwards, with a follow up of 4 years. Length of warm ischaemia during the procedure is of particular importance, with a mean of 28 minutes (range 9-60 mins) reported in this study. There was a change in split renal function of 6%. Patients in this study were on the whole young, fit and slim with small favourably located tumours.