Materials and Methods: Open surgical partial nephrectomy with hilar clamping was performed in pigs weighing 150 to 200 lbs, includingsmall-a quarter length and a quarter width of kidney, medium-a third length and a third width of kidney, and into the renal sinus and up to thecollecting system, and large-lower pole heminephrectomy at the renal sinus. Seven agents were compared after a single application, namelythrombin/collagen granules, polyethylene glycol hydrogel, fibrin glue, thrombin/gelatin granules, cyanoacrylate glue, fibrin glue/gelatin sponge andsutured bolster. Failure and success were determined by the presence or absence of bleeding, respectively, after unclamping and by an increasein SBP to 100 and then to 200 mm Hg with dopamine infusion.

Results: Of 70 partial nephrectomies the success rates were 33% and 14% for thrombin/collagen granules, and 67% and 0% for polyethyleneglycol hydrogel in small and medium resections; 100%, 71% and 0% for fibrin glue, and 100%, 86% and 0% for thrombin/gelatin granules in small,medium and large resections; and 67% and 80% for cyanoacrylate glue, 100% and 20% for fibrin glue/gelatin sponge, and 100% for sutured bolsterin medium and large resections, respectively. Of the kidneys that did not bleed at an SBP of 100 mm Hg 31% bled at 200 mm Hg.

Conclusions: There is considerable variability among agents. Most were effective for small resections and some worked for medium resectionsbut for large resections only sutured bolster was consistently effective. SBP also appears to be an important factor. These results bear on theselection of techniques during laparoscopic partial nephrectomy.

Commentary

Multiple different hemostatic agents have been used to control bleeding after laparoscopic partial nephrectomy, but it has been difficult toidentify a clearly superior agent because few comparative trials have been performed. To address this shortcoming, the authors used dopamine tocreate a hypertensive (systolic blood pressure of 200 mm Hg) porcine kidney model and then tested multiple hemostatic agents using 3 differentstandardized sizes of renal resection: small, a quarter length and a quarter width of kidney; medium, a third length and a third width of kidney;and large, lower pole heminephrectomy. Unfortunately, the number of treatment groups precluded statistical analysis, but the results were sufficientto draw general conclusions. After large resections, cyanoacrylate glue was somewhat effective, stopping bleeding in 80% of cases. Still, nohemostatic agent approached the 100% effectiveness of sutured bolsters. Thrombin/gelatin granules, fibrin glue, and fibrin glue plus gelatin spongeworked well for medium resections, but no surgeon would be happy with the hemostatic success rate of 0% to 20% these agents achieved afterlarge resection. The remaining agents (polyethylene glycol hydrogel and thrombin/collagen granules) had limited effectiveness, even for smallresections.

It takes little experience with partial nephrectomy to realize that the difficulty controlling bleeding increases greatly with proximity to largecentral vessels. The results of this study confirm this point well. There were multiple agents that were effective for small resections in this porcinemodel, but for large resections, sutured bolsters were required. Translating these data to human beings is somewhat difficult because it is not clearwhat exact size of resection in a human being correlates to the medium and large resections in this hypertensive pig model. However, clinicalreports on laparoscopic partial nephrectomy suggest that after smaller resections, a hemostatic agent alone can be successful, while sutured bolstersimprove outcomes after larger and deeper resections [1,2]. This being said, the remaining question for these hemostatic agents may be which oneis most effective when used in conjunction with sutured bolsters after large resections.

doi:10.1016/j.urolonc.2006.08.024Kyle Anderson, M.D.

References

[1] Finley DS, Lee DI, Eichel L, et al. Fibrin glue-oxidized cellulose sandwich for laparoscopic wedge resection of small renal lesions. J Urol2005;173:1477–81.

[2] Johnston WK III, Montgomery JS, Seifman BD, et al. Fibrin glue v sutured bolster: Lessons learned during 100 laparoscopic partial nephrectomies. J Urol2005;174:47–52.

Bloodless partial nephrectomy with a new high-intensity collimated ultrasonic coagulating applicator in the porcine model. MuratFJ, Lafon C, Cathignol D, Theillere Y, Gelet A, Chapelon JY, Martin X, Department of Urology, Edouard Herriot Hospital, Lyon, France.

Urology 2006;68:226–30

Objectives: To evaluate the long-term hemostatic efficacy of a new high-intensity collimated ultrasonic (HICU) applicator for opensubhilar partial nephrectomy (PN) in the porcine model.

Methods: An applicator was designed with a planar 3.78-MHz HICU transducer and a reflector to optimize the delivery of acousticenergy to coagulate renal tissue. Six female pigs underwent right PN, followed at day 7 by left PN. The 6 pigs were killed on day 14. Thetreatment consisted of delivering HICU to a lower pole subhilar location, under a vascular clamp, then releasing the clamp, and cutting thekidney lower pole. The immediate and delayed hemostatic efficacy, treatment parameters, blood loss, complications, and renal function wereevaluated at each surgical event and at necropsy.

Results: Perfect hemostasis was achieved with all 12 kidneys, with a mean treatment time of 7.2 minutes (range 5 to 9.2). The meanproportion of resected parenchyma was 21% (range 14% to 32%). No renal function impairment and no major complications were recorded.At necropsy, no secondary hematoma was observed, and three urinomas (25%) were found.

Conclusions: Our HICU applicator has shown promising results during PN in the pig model with no other method of hemostasis. Morestudies are needed to refine our probe for laparoscopic surgery, improve its ergonomics, and extend our experiments to human laparoscopicnephron-sparing surgery.

94 K. Anderson / Urologic Oncology: Seminars and Original Investigations 25 (2007) 87–95

Commentary

This is an interesting report on the use of high intensity ultrasound to achieve hemostasis within a section of the renal parenchyma. Toperform this procedure, a total of 12 kidneys were treated with an ultrasound device to create a hemostatic boundary across the lower renalpole. A knife was then used to remove the lower pole. Despite removing 21% of the kidney by mass and frequently entering the collectingsystem, there was negligible blood loss in 9 kidneys. In the remaining 3 kidneys, a second ultrasound treatment was necessary, but the bloodloss was only 25 ml. No additional hemostatic maneuvers were needed to control bleeding, but the ultrasound was not effective in closingthe collecting system because 25% of the kidneys had urinomas.

This technology is in an early stage of development, and, thus, the investigators made concessions in their experimental methods (i.e.,use of an open incision for device placement and hilar clamping during ultrasound treatment) that would not be optimal clinically. Inaddition, no effort, such as increasing the blood pressure, was made to better mimic human renal physiology. Regardless, this technique doeshave a number of appealing aspects that make it potentially useful for laparoscopic partial nephrectomy if further engineering improvementscan occur. First, the use of ultrasound energy may allow switching between treatment and imaging of the kidney on a rapid time scale. Thisimaging would conceivably allow better targeting of coagulation and possibly confirm the effectiveness of the coagulation. Next, the abilityto coagulate blood flow to the region of a tumor followed by removal of the tumor with cold knife or scissors (as was performed in thisstudy) should allow comparable visualization of tumor margins to current partial nephrectomy techniques. Finally, the ability to retreat easilytissue if bleeding occurs during resection is appealing.

As discussed in the previous article, the sutured bolster remains the king of the hill for hemostatic control after a large resection. However,it is likely just a matter of time before an energy based technology such as this one provides comparable hemostasis to sutured bolsters afterlaparoscopic partial nephrectomy.

doi:10.1016/j.urolonc.2006.08.025Kyle Anderson, M.D.

Second prize: Simple method for achieving renal parenchymal hypothermia for pure laparoscopic partial nephrectomy. WebsterTM, Moeckel GW, Herrell SD, Department of Urology, Vanderbilt University Medical Center, Nashville, TN.

J Endourol 2005;19:1075–81

Purpose: We describe the development of an innovative device and simple technique for achieving renal parenchymal hypothermiaduring temporary renal-vascular occlusion for pure laparoscopic partial nephrectomy.

Materials and Methods: The experiment was conceived in four phases: phase 1: design, manufacture, and testing of the cooling coil;phase 2: proof of concept in nonsurvival porcine surgery; phase 3: experimental porcine survival surgery; and phase 4: human trials.

Results: Phase 1 testing confirmed that the coil cooled adequately. During phase 2, the average time required for the renal parenchymato cool to 15°C was 10.7 minutes, providing an average hypothermic window (15°–24°C) of 30.3 minutes. When recooling was required(parenchymal temperature 24°C), temperatures returned to below 15°C in 3 minutes. The core body temperature dropped an average of1.48°C. Phase 3 demonstrated an average parenchymal temperature of 11.7°C after a mean cooling time of 9.3 minutes. Temperaturesremained below 24°C for an average of 26.7 minutes. Recooling took 3 minutes, and in no procedure did the renal parenchyma temperaturesever return to �24°C prior to reperfusion. The core body temperature dropped an average of 2.20°C. At 48 hours after reperfusion, selectiverenal-vein blood was obtained for creatinine assay, and the kidneys were harvested. Creatinine results were not statistically different in thetreated and control groups. Blinded pathologic analysis confirmed a protective effect using our cooling system.

Conclusion: Our method is simple, effective, and reproducible.

Commentary

During laparoscopic partial nephrectomy, the maximal duration of warm ischemia allowable before the onset of significant renal damagecontinues to be a topic of debate. To add more complexity to the problem, there probably is variation among patients in the time to ischemicdamage, and no method exists for predicting preoperatively or actively monitoring intraoperatively for renal injury. The time-tested wayaround this time limit, regardless of what the time limit is, has been renal hypothermia. However, in the laparoscopic setting, establishingrenal hypothermia has been technically difficult and is not widely used.

Here, Webster et al. describe a simple and effective method of obtaining renal hypothermia during laparoscopic partial nephrectomy usingcooled saline. The technique was effective in cooling the porcine kidney, with a minimal decrease in systemic temperature. In addition, therequisite device would fit well with the current laparoscopic technique, and could be easily set up and treated by surgical nursing staff.

Further work will be required to determine if these results can be reproduced in the larger human kidney and if active temperaturemonitoring of the kidney is required during cooling. However, based on the available animal work, success in human beings seems likely.If this is truly the case, this technique is simple enough that renal hypothermia during laparoscopic partial nephrectomy will become anattractive possibility.

doi:10.1016/j.urolonc.2006.08.026Kyle Anderson, M.D.

95K. Anderson / Urologic Oncology: Seminars and Original Investigations 25 (2007) 87–95