OBJECTIVETo assess the effects of warm ischaemia time (WIT) on renalfunction after laparoscopic partial nephrectomy (LPN) for renal masses in patients.

METHODSFrom January 2010 to December 2012, 39 patients treated with LPN for a single T1 renal tumor were enrolled in this prospective study. There were 24 male and 15 female patients. Their age was (58 ± 10) years old, and their body mass index was (27 ± 3) kg/m(2). The mean operation time was (132 ± 12) minutes, and the mean WIT was (29 ± 8) minutes. Clinical parameters, the single glomerular filtration rates (sGFR) were compared before the operation and after 3 and 12 months in order to observer the effects on renal function and find the factors predicting the renal function impairment.

RESULTSThere were significant differences between 3, 12 months after the operation ((26.8 ± 5.6) ml/min and (28.6 ± 5.6) ml/min, respectively) and preoperation ((31.9 ± 6.3) ml/min) in sGFR (F = 4.882 and 5.511, both P < 0.05). And there were significant negative correlations between the sGFR in 3 and 12 months after the operation and WIT (r = -0.569, P = 0.000 and r = -0.448, P = 0.004) . The preoperative sGFR (β = 0.260, 95%CI:0.089-0.431) and WIT (β = 0.369, 95%CI:0.189-0.555) were independent predictors for function decline of the operated kidney (both P < 0.05). The analysis showed that the effects of WIT within 30 minutes on renal function is relatively small. Longer WIT was associated with lower postoperative sGFR values (F = 22.128 and 20.552, both P = 0.000) .

CONCLUSIONSFor the LPN operation, the longer of the WIT, the more serious of renal function damage. sGFR is an accurate measurement to assess the renal damage. Every effort should be made to minimise WIT during LPN, and the limit of 30 minutes should be not exceeded.