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BackgroundAs laparoscopic partial nephrectomy increases in prominence, more needs to be understood about the combined effect of the pneumoperitoneum and renal ischemia during tumor resection. The purpose of this study is to investigate the effect of combined renal hilar clamping (arterial only versus arteriovenous) and retrograde intrarenal cooling on renal temperature and oxygenation in a porcine laparoscopic partial nephrectomy model.Materials and MethodsUnder general anesthesia, laparoscopic access with intra-abdominal pressure of 15mmHg to the left renal hilum was obtained. Licox®tissue oxygenation and temperature probes were placed into the kidney transcutaneously; measurements were taken every 30 seconds. After establishing baseline readings, either the artery alone (n 18) or the artery and vein (n 18) were clamped for 30, 60 or 90 minutes (n 12 each). During vascular clamping, retrograde, intrarenal cooling was performed with ice cold saline infused via a percutaneously placed ureteric catheter in 18 pigs. Changes in renal pO2and temperature were analyzed with repeated measures ANCOVA in SPSS 16.ResultsRetrograde cooling decreased renal parenchyma to 75.8 of baseline temperature (27.9°C) within 15 minutes. There were no differences in cooling whether arterial or arteriovenous clamping was used (p 0.79). In uncooled animals, there was no significant difference in the decrease in renal pO2during the clamp phase (p 0.18) or during the recovery phase (p 0.52). During the recovery phase, renal pO2in uncooled animals was significantly higher than in those who received cooling (p 0.01). Animals who underwent hilar clamping for extended periods (60 and 90min) had a slower recovery of renal pO2to baseline than those with hilar clamping for 30 minutes (p 0.04)ConclusionRetrograde intrarenal cooling can reliably cool the porcine kidney to 28°C, regardless of whether arterial or arteriovenous clamping is used. Renal pO2is not significantly different between animals that undergo artery only versus en bloc hilar clamping. Pigs that were provided with retrograde cooling had a slower return of pO2to baseline following release of hilar clamps, possibly due to hypothermic vasospasm. Clamp durations greater than 60 minutes were also associated with slower return of renal oxygenation to baseline. [ABSTRACT FROM AUTHOR]

Background and Purpose The use of stone baskets for repositioning of stones or removal of fragment in conjunction with ureterorenoscopy has become widespread. We tested the performance of the ACMI Sur-Catch NT, Bard Dimension, Boston Scientific Zero-tip, and Cook N-Circle in a pig kidney model of flexible ureterorenoscopy.Materials and Methods Opening characteristics of the basket were measured with mechanical calipers at 1-mm increments and compared with published reports to ensure the tested baskets were representative. Pig kidneys were placed in a basin and the ureters secured with a suture to a weight for stability. Flexible renoscopy was performed using a 16F flexible cystonephroscope. An 8-mm calculus was placed in the lower pole. Using each of four designs, the time necessary to grasp the stone, time to release the stone, and total time to move a stone from the lower-pole calix to the upper-pole were recorded. Total time experiments were repeated six times with each basket by three surgeons for a total of 18 attempts, and catch-and-release experiments were repeated six times by four surgeons for a total of 24 attempts per basket.Results The Sur-Catch was significantly slower for catch and release (P< 0.001) and total time; P< 0.05) compared with all other baskets. There were no differences between the other baskets in either catch, release, or total times. There was no difference between surgeons (P< 0.0634) or between attempts one through six (P 0.538).Conclusions Baskets with added complexity of the wire configurations (Sur-Catch) or a deflectable-wire mechanism (Dimension) offer no advantages and may slow capture and release of stones. [ABSTRACT FROM AUTHOR]