Background and Objectives: The flow characteristics of ureteral stents have yet to be clearly defined. In this study, flow mechanics were studied in several silicone-based stents including 4.8F, 7F, and 10.3F pigtail; 7F Tower; and a prototype mesh stent, Materials and Methods: Forty-five female Yucatan minipigs underwent bilateral laparoscopic occlusion of their renal vessels to stop urine production. A nephrostomy tract was established by retrograde puncture. A stent was placed in the ureter, and three measurements were taken with flow from a bag of irrigant 20 cm above the kidney: stent occluded with a guidewire (extraluminal flow), stent unobstructed (total flow), and laparoscopically placed extraureteral ligature (luminal flow). Results: Luminal flow and, to a lesser extent, total flow appeared to increase as the internal and external diameters of the stent increased. The Tower stent, which had no sideholes, had much lower flow rates in all categories, while the prototype mesh stent showed greater total flow compared with the other stents, Extraluminal flow did not increase with stent size greater than 7F, Conclusions: Luminal flow, but not extraluminal flow, increased with an increase in the internal diameter of the stent. In general, the least favorable Bow occurred with a Tower stent, which had the smallest internal diameter. The greatest flow was seen with the prototype mesh stent.

INTRODUCTION:Laparoscopic partial nephrectomy has emerged as a standard of care for small renal masses. Nevertheless, there remains concern over the potential for irreversible insult to the kidney as a result of exposure to warm ischemia. We aim to investigate the utility of selective segmental arterial clamping as a means to reduce the potential for ischemic damage to a solitary kidney during laparoscopic partial nephrectomy utilizing a porcine model.MATERIALS AND METHODS:A total of 20 domestic swine were randomized into four equal groups. Each subject underwent laparoscopic radical nephrectomy to create the condition of a solitary kidney. On the contralateral side, a laparoscopic lower pole partial nephrectomy was performed, employing either selective or nonselective vascular clamping for either 60 or 90 minutes. Postoperatively, clinical status and serial serum studies were closely monitored for 1 week.RESULTS:There were no intraoperative complications. The 90-minute nonselective clamping produced devastating effects, resulting in rapid deterioration into florid renal failure within 72 hours. The 60-minute nonselective clamping group experienced modest but significant rises in both blood urea nitrogen and creatinine. Both 60- and 90-minute selective clamping groups performed well, with no significant rises in creatinine over a 7-day period, and no instances of renal failure.CONCLUSIONS:Selective arterial clamping is a safe and feasible means of vascular control during laparoscopic partial nephrectomy. In the porcine model, selective clamping appears to improve functional outcomes during prolonged periods of warm ischemic insult. Prospective evaluation of the technique in humans is necessary to determine if selective arterial control confers long-term functional benefits in patients with limited renal reserve.

Background and Purpose: Laparoscopic retroperitoneal lymph node dissection (L-RPLND) is emerging as a viable alternative to traditional open retroperitoneal lymph node dissection (O-RPLND). Despite numerous reports confirming clinical oncologic equivalency between the two approaches, however, concerns still remain over the adequacy of laparoscopic dissection. We therefore sought to compare the completeness of dissection between O-RPLND and L-RPLND in a porcine model. Materials and Methods: Fourteen domestic swine were divided into two equivalent groups. Both groups underwent bilateral retroperitoneal lymph node dissection, approximating templates used in human dissection. In one group, the procedure was performed through an open midline incision, while the other group underwent completely laparoscopic dissection. Tissue was independently analyzed by a pathologist, who recorded lymph node yield based on microscopic evaluation. Results: All animals in the L-RPLND group underwent successful procedures, without the need for conversion. Two open procedures were aborted because of hemorrhage. Mean lymph node yield from O-RPLND was 32, while the mean yield for L-RPLND was 29. This difference was not statistically significant (P = 0.65). Conclusions: In the porcine model, L-RPLND is capable of providing a quality of dissection equivalent to that of O-RPLND, in terms of absolute lymph node yield on microscopic examination. The applicability of this data to human patients, however, may be limited by significant anatomic differences between the human and the pig. Further prospective comparison in human patients is critically needed.

OBJECTIVETo evaluate the precision of cryoprobe targeting with a surface template, an in situ template (on the target organ), or a combined approach.MATERIALS AND METHODSFourteen participants placed five 17 G cryoprobes into porcine kidneys in a laparoscopic trainer using a surface template (group 1), an in situ template (group 2) or a combination of the two templates (group 3). The distance from the ideal probe placement was measured both on the anterior and posterior aspect of the kidney. The sequence of attempts was randomized. The distances were compared across the three groups using anova with the adjustment for multiple comparisons.RESULTSThe mean distance from the ideal probe placement was 1.58 cm (anterior) and 1.81 cm (posterior) in group 1, 0.05 cm and 0.39 cm in group 2, and 0.07 cm and 0.22 cm in group 3, respectively. The placement of the probes was significantly more accurate in groups 2 (P < 0.001 anteriorly and P < 0.002 posteriorly) and 3 (P = 0.001 anteriorly and P < 0.001 posteriorly) compared with group 1. There was no significant difference between groups 2 and 3.CONCLUSIONIn this in vitro model, the use of internal or combined internal and external templates allows for significantly more precise deployment of 17‐G cryoprobes than a standard external template alone.

Cryoablation of renal masses is an evolving in situ ablative technique for the management of localized renal masses and can be performed in a laparoscopic or percutaneous manner. Its usefulness is increasing and correlates with the increasing frequency of incidentally diagnosed renal lesions. At present, this technique has been applied to patients deemed to be poor surgical candidates for extirpative therapy or those with a strong desire to avoid surgery, at least until long-term data become available to fully evaluate its cancer-control effectiveness. In addition, as costs become an ever more critical factor in healthcare, the costs of various management options for clinically localized kidney cancer will become as important as clinical outcomes in deciding appropriate treatment. We compare laparoscopic and percutaneous renal cryoablation from a cost perspective. Our findings indicate that percutaneous renal cryoablation may have distinct cost advantages over its laparoscopic counterpart. It remains to be seen whether these differences will translate into an overall increase in reliance on the percutaneous approach for renal cryoablation.

In this manuscript some of the more common laparoscopic procedures and their indications will be reviewed.

Following the anastomosis and the final catheter placement, the prosthesis is completely deflated, inflating the reservoir.RESULTS: This technique for managing the reservoir of an IPP results in preservation of the prosthesis.CONCLUSIONS: RALRP is a feasible option for patients with an IPP and clinically localized prostate cancer.

You have accessJournal of UrologyModerated Poster 51, Tuesday, May 22, 2007, 3:30 - 5:30 pm1 Apr 20071645: Effects of Different Hydrational States on Ureteral Dynamics and Stone Movement in a Porcine Model: An in Vivo Study Ramakrishna Venkatesh, Mohamed Soliman, Geneva Baca, Steve LaBarbera, Micheal Talcott, Sam B. Bhayani, Keegan L. Maxwell, Khalid H. Badwan, and Robert S. Figenshau Ramakrishna VenkateshRamakrishna Venkatesh More articles by this author , Mohamed SolimanMohamed Soliman More articles by this author , Geneva BacaGeneva Baca More articles by this author , Steve LaBarberaSteve LaBarbera More articles by this author , Micheal TalcottMicheal Talcott More articles by this author , Sam B. BhayaniSam B. Bhayani More articles by this author , Keegan L. MaxwellKeegan L. Maxwell More articles by this author , Khalid H. BadwanKhalid H. Badwan More articles by this author , and Robert S. FigenshauRobert S. Figenshau More articles by this author View All Author Informationhttps://doi.org/10.1016/S0022-5347(18)31833-0AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "1645: Effects of Different Hydrational States on Ureteral Dynamics and Stone Movement in a Porcine Model: An in Vivo Study." The Journal of Urology, 177(4S), pp. 545–546 © 2016 by American Urological AssociationFiguresReferencesRelatedDetails Volume 177Issue 4SApril 2007Page: 545-546 Advertisement Copyright & Permissions© 2016 by American Urological AssociationMetricsAuthor Information Ramakrishna Venkatesh More articles by this author Mohamed Soliman More articles by this author Geneva Baca More articles by this author Steve LaBarbera More articles by this author Micheal Talcott More articles by this author Sam B. Bhayani More articles by this author Keegan L. Maxwell More articles by this author Khalid H. Badwan More articles by this author Robert S. Figenshau More articles by this author Expand All Advertisement PDF DownloadLoading ...

Objectives To develop and test a porcine model to help teach the techniques needed to perform laparoscopic partial nephrectomy (LPN), which is a technically challenging procedure with necessary reconstructive skills that are difficult to transfer. Methods A tumor model was created by unilateral subcapsular percutaneous injection of liquid plastic (Smooth-Cast 320) in five pig kidneys. Five Washington University urologists performed LPN and assessed the efficacy of the tumor model. Subsequently, the tumor model was evaluated as a tool for teaching LPN during the Washington University Advanced Laparoscopic and Robotic Urologic Oncology Course. Twenty-eight participants performed unilateral porcine LPN with the tumor model. Questionnaires were used to assess the utility of this tumor model. Results Unilateral tumors were successfully created in five pigs and remained intact during all LPN procedures. Visually, the tumors appeared as white exophytic masses. Ultrasonography revealed a well-circumscribed, hypoechoic lesion and a mean diameter of 2.02 cm. The mean operative time was 32.4 minutes. In subsequent testing, 24 (86%) of the 28 participants returned the questionnaire, and 96% responded that the tumor model had enhanced their LPN learning experience. Seven course participants (29%) reported problems with hemostasis, ultrasonography, or laparoscopic instrumentation. Two tumor model-related complications occurred. During the initial evaluation, one pig experienced a fatal pulmonary embolism of the plastic. During the course, a second animal experienced extravasation of the solution into the renal collecting system. Conclusions For surgical education purposes, the Smooth-Cast model is an effective surgical tool for LPN. Most of the surgeons in this evaluation believed the model enhanced their learning experience.

You have accessJournal of UrologyVideo Session, Wednesday, May 12, 2004, 1:30 - 3:30 pm1 Apr 2004V1974: Nerve-Sparing Retropubic Radical Prostatectomy - A Video of the Technique Keegan L. Maxwell, and William J. Catalona Keegan L. MaxwellKeegan L. Maxwell More articles by this author , and William J. CatalonaWilliam J. Catalona More articles by this author View All Author Informationhttps://doi.org/10.1016/S0022-5347(18)39215-2AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "V1974: Nerve-Sparing Retropubic Radical Prostatectomy - A Video of the Technique." The Journal of Urology, 171(4S), p. 521 © 2016 by American Urological AssociationFiguresReferencesRelatedDetails Volume 171Issue 4SApril 2004Page: 521 Advertisement Copyright & Permissions© 2016 by American Urological AssociationMetricsAuthor Information Keegan L. Maxwell More articles by this author William J. Catalona More articles by this author Expand All Advertisement PDF DownloadLoading ...

Objective: We elected to evaluate laparoscopic segmental bladder and ureteral replacement with free biodegradable graft materials in a large-animal model.Materials and Methods: In 18 Yucatan minipigs, a 1.5- to 2.8-cm segment of the upper ureter was excised. In 15 study animals, the ureter was laparoscopically replaced: by a stinted (6F double-J stent) tube graft made of acellular matrix (AMX) prepared from minipig ureters (MUMX) in 6 animals, acellular matrix prepared from domestic pig ureters (DUMX) in 3, and small-intestinal submucosa (SIS) in 6. In 3 control animals, the ureteral gap was bridged only by an indwelling stent, The stent was removed at 6 weeks, and retrograde ureteropyelography was performed preoperatively and at 8 and 12 weeks postoperatively, when animals were sacrificed. In 18 Yucatan minipigs, 3 x 3-cm bladder dome segments were laparoscopically replaced: by acellular matrix prepared from minipig small bowel (MBMX) in 6 animals, and SIS in 6 animals, The bladder was closed primarily in 6 control animals, Bladder capacity was assessed preoperatively and at 6 and at 12 weeks, when the animals were sacrificed,Results: The average operating time for ureteral replacement was 187 (range 105-360) minutes. At 12 weeks, all animals had complete obstruction at the level of the replacement, with fibrosis +/- bone formation at the level of the stricture, For the bladder replacement groups, the average operating time was 147 (range 85-200) minutes. At 12 weeks, the bladder capacity was 60% of the preoperative capacity in the control group, 118% in the MBMX group, and 142% in the SIS group, Histologic examination showed regeneration of urothelium and some muscle with both MBMX and SIS,Conclusions: We were able to develop a reliable laparoscopic technique for both segmental ureteral and partial bladder replacement in a porcine model. With AMX and SIS replacement, regeneration of urothelium occurred in both ureter and bladder, However, functional replacement was successful only in the bladder.