546 less surgical field is even more important for these aims to be achieved without prolonging the warm ischemia time [16]. Relevant devices and instruments should not damage the vascular endothelium and should be easily taken down after the tumor excision and reconstruction of the defect are completed. The laparoscopic bulldog clamp or the Satinsky clamp, i.e., the metallic tools that have traditionally been used for transient vascular occlusion, are apt to damage the vascular endothelium because of their tight clamping [12]. In the case of the laparoscopic bulldog clamp, it may be diffi- cult to apply it precisely and to take it down easily when there is imprecise alignment between the bulldog clamp and its applicator. In the case of the Satinsky clamp, one additional laparoscopic port is needed and kidney mobi- lization may be limited. 　Such problems can be overcome by our technique using the Hem-o-lok clip and the vessel loop. Hem-o-lok clips are common tools used by all laparoscopic surgeons [17]. In the arena of LPN, Canales and associates described their use in the closure of renal parenchymal defects after tumor ex- cision [18]. In our technique, the accessibility of devices and applicators is not a consideration and an additional laparo- scopic port is not required. Because the vessel loop is elas- tic, the risk of mechanical injury to the vascular endothe- lium is minimal. In addition, vascular occlusion can be easily terminated because the laparoscopic scissors can snip at the vessel loop. Furthermore, our technique benefits from reasonably priced devices. We applied this technique to clamping of both the renal artery and the renal vein suc- cessfully, and thus the size and the multiplicity of vessels are not an issue. 　Rosales et al and colleagues and Hacker et al and asso- ciates performed LPN by applying Rummel’s tourniquet technique and reported its usefulness [5,19]. For reference, Rummel’s tourniquet technique controls tension by mak- ing a once-folded vessel loop pass through a plastic feeding tube. Their method and our technique are similar in tools and mechanism. Although our technique is motivated by them, we simplified the technique and successfully per- formed operations. 　In open partial nephrectomy, Ko and associates reported the efficacy of the parenchymal compression method [20]. They had acceptable outcomes in terms of complete tumor control, avoiding warm ischemic time, and minimizing bleeding, with good preservation of renal function and minimal complications. But this technique cannot be adopted because of the difficulty in the application of in- struments in laparoscopic surgery. 　The advancement of surgical techniques in laparoscopic and robotic surgery and the introduction of the ultrasonic knife have enabled operators to perform partial neph- rectomy without renal artery clamping and to minimize the damage to renal function [21,22]. In the case of surgeries without renal artery clamping, however, operators may ex- perience difficulty in performing the surgeries if they have not overcome the learning curve of laparoscopic or robotic surgeries. Furthermore, application of this technique is Korean J Urol 2011;52:543-547 Lee et al limited to patients with an exophytic, small renal tumor. 　The greatest advantage of our technique is the simplicity and the ease by which transient vascular clamping is ap- plied and released. This considerably shortened the warm ischemia time despite our limited experience with LPN. Although the cases in this study are all the cases of LPN that we have ever performed, the mean warm ischemia time was 26.1 minutes (range, 18-34 minutes), which is rel- atively short. Thus, our technique is a useful alternative for less-experienced surgeons as well as for laparoscopic experts. 　For investigating precise ischemic renal function, a MAG3 or DTPA renal scan is needed. In our study, the method used to evaluate ischemic renal function was not complete because the serum creatinine level and GFR can- not reflect split renal function. The limitations of our study include the small number of patients, the small number of oncologic events, and that this was a noncomparative study. More cases of renal cell carcinoma and long-term fol- low-up are needed to determine oncologic results. Clinical comparative studies between the various occlusion devices (laparoscopic bulldog, Satinsky clamps, Rummel’s tourni- quet, and the vessel loop with Hem-o-lok clips) may show the effectiveness and the merits of each technique.  CONCLUSIONS Our transient vascular occlusion technique that uses a ves- sel loop and Hem-o-lok clips was shown to be simple, ex- peditious, and safe in LPN. Although further comparative studies and long-term data are needed, we suggest that this technique can be a feasible and an acceptable alternative to standard vascular occlusion techniques, such as laparo- scopic bulldog or Satinsky clamps, in LPN. Conflicts of Interest The authors have nothing to disclose. REFERENCES 1. Chow WH, Devesa SS, Warren JL Fraumeni JF Jr. Rising in- cidence of renal cell cancer in the United States. JAMA 1999;281:1628-31. 2. Russo P. Open partial nephrectomy: an essential operation with an expanding role. Curr Opin Urol 2007;17:309-15. 3. Allaf ME, Bhayani SB, Rogers C, Varkarakis I, Link RE, Inagaki T, et al. Laparoscopic partial nephrectomy: evaluation of long- term oncological outcome. J Urol 2004;172:871-3. 4. Lane BR, Gill IS. 5-year outcomes of laparoscopic partial nephrectomy. J Urol 2007;177:70-4. 5. Rosales A, Salvador J, De Graeve N, Angerri O, Villaicencio H. Clamping of the renal artery in laparoscopic partial nephrectomy: an old device for a new technique. Eur Urol 2005;47:98-101. 6. Ho HS, Peschel R, Neururer R, Steiner H, Schwentner C, Bartsch G. Another novel application of Hem-o-Lok clips for transient vas- cular occlusion in robot-assisted laparoscopic partial neph- rectomy: an alternative to laparoscopic bulldog and satinsky clamps. J Endourol 2008;22:1677-80.