Purpose: To investigate changes in renal function after retroperitoneal laparoscopic partial nephrectomy (LPN) with renal hypothermia induced by ice-slush cooling.
Patients and methods: Seventy-one patients undergoing retroperitoneal LPN with renal hypothermia were included. Perioperative outcomes were reviewed retrospectively. The total renal function was evaluated by an estimated glomerular filtration rate (eGFR) preoperatively and 6 months postoperatively in 69 patients. Split renal function (SRF) was also evaluated by 99mTc-mercaptoacetyltriglycine scintigraphy preoperatively and 6 months postoperatively in 61 patients.
Results: The median operative time was 246 minutes (range, 155-424). The median cold ischemic time, including the initial 15 minutes of hypothermia, was 57 minutes (range, 34-112). In the 21 patients whose renal temperature was monitored, median lowest renal temperature was 20.7°C (range, 12.1-27.6). The median baseline eGFR and 6-month postoperative eGFR were 77.2 mL/min/1.73 m(2) (range, 36.1-121.3) and 68.3 mL/min/1.73 m(2) (range, 33.2-103.4), and the median baseline SRF and 6-month postoperative SRF of the affected kidney were 49.3% (range, 40.3-57.6) and 40.7% (range, 13.8-54.5). Using multivariate analysis, the baseline eGFR (p<0.0001) and the ischemic time (p=0.0073) were associated with the 6-month postoperative eGFR, and the 6-month postoperative SRF was only associated with a baseline SRF (p=0.0185).
Conclusions: Ice-slush cooling could provide renal hypothermia also under LPN. The decrease in renal function was small, whereas our ischemic time was longer than experts' warm ischemic series. These observations suggested the protective effect of our cooling methods against ischemic injury.