MP-05.05: Intrarenal manipulation of flexible ureteroscopes: A comparative study

MODERATED POSTER SESSIONS

calculi fragments – whether in the kidney or in the ureter. Patients were discharged on the same day. Review of X-rays was done after 7-10 days, and patient would undergo stent removal, repeat ESWL with stent removal or, in few patients, repeat URS with contact lithotripsy with stent removal. Results: Of the 78 patients, there was one failure due to “hypermobility of the ureter”. She opted for open ureterolithotomy. There were 6 perforations – all were managed conservatively with 3 weeks of D-J stenting. There was one patient where the procedure was successful; however there was an ureterovesical junction avulsion during the withdrawal of the URS; she was managed conservatively with D-J stent initially, but later required a Boari Flap ureteroneocystostomy. No patients required immediate admission; no blood transfusions were given. Two patients required subsequent admission for septicemia; these responded to intravenous antibiotics. Conclusion: We feel that in experts’ hands, the management of large upper third ureteric calculi by a combination of rigid URS, contact lithotripsy and ESWL, is a relatively safe, effective and minimally invasive method of treatment MP-05.04 In vitro evaluation of ureteral perforation forces Monga M, Hendlin K, Weiland D, Ramani A, Kohler T, Anderson K University of Minnesota, Minneapolis, USA Introduction: Ureteral perforation is a known complication that can occur with the use of a ureteral basket, guidewire, access sheath or ureteroscope. Our objective was to quantify ureteral perforation and avulsion forces in human and porcine models. Methods: In 6 fresh porcine kidneys a 10mm stone was placed in a stone extraction basket through an incision in the renal pelvis, which was then sutured. The basket was attached to a miniature, lowforce load cell (Sensotec, Columbus, OH) and slowly pulled with increasing force until the ureter avulsed. Ten fresh porcine and 2 human ureters were bisected longitudinally and secured between 2 annular disks and fine sand paper with a 0.5cm circular opening. Perforation with either the blunt end of a CT-1 needle (0.038‘) or the back end of a Boston Scientific Superstiff guidewire (0.035‘) was measured using the same load cell. Maximum force readings were recorded for both tests.

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Results: The average maximum force to avulse the pig ureters was 2.21⫾0.43 lbm (pound-mass). Greater force was required to perforate with the needle than the guide wire in the porcine ureter (1.57⫾0.36 lbm vs. 1.24⫾0.49 lbm, p⫽0.003) as well as the human ureter (1.12⫾0.19 lbm vs. 0.82⫾0.22 lbm, p⫽0.04). Perforation was significantly higher in the pig compared to the human ureter using the needle (p⫽0.01). Conclusions: Ureteral perforation forces differ depending on the instrument deployed and species tested. This information is of importance for training urologists and scrub nurses, the development of surgical simulators and the creation of force-sensitive instruments. MP-05.05 Intrarenal manipulation of flexible ureteroscopes: A comparative study Monga M, Weiland D, Lynch AC, Rashid H, Canales B, Jones M, Kohler TS, Nakib N, Ramani A, Anderson J University of Minnesota, Minneapolis, USA Introduction: New generation flexible ureteroscopes provide exaggerated active deflection to facilitate intrarenal manipulation. We compared the relative ease of manipulation around a calyceal model in the hands of experienced ureteroscopists. Methods: Eight experienced ureteroscopists (⬎100 URS/3 years) tested the following ureteroscopes ⬍7.5 Fr. in size: Stryker FlexVision U-500 (STRYK), ACMI Dur-8 Elite (ACMI), Wolf Viper (WOLF), and Olympus URF-P3 (OLY). The Mediskills Calyceal Model represents a hydronephrotic collecting system, (pelvic width 2cm, infundibular widths 1cm, infundibular lengths 2cm). The infundibular angles were 80-degrees for the middle calyx and 100-degrees for the lower calyx. The model does not allow for significant passive secondary deflection. The surgeons completed a 4-point course, from the ureteropelvic junction to anterior lower calyx to anterior middle calyx to posterior lower calyx to posterior middle calyx, touching a metal sensor with an ACMI electrode to trigger an automated signal at each calyx. The order of endoscope used by each surgeon was randomized. Each surgeon performed the course twice with each scope, ending with the first scope they started with to diminish the impact of ‘learning the course’. Results: Significant differences in the mean total time for manipulation through the 4-point course were noted for the WOLF (29⫾11s), STRYK (37⫾23s), ACMI

(38⫾20s), and OLY( 50⫾24s)(p⫽0.034). The OLY took longer to reach the posterior lower pole (18.1⫾14.5s) compared to the WOLF (6.3⫾2.8s, p⫽.004), STRYK (6.6⫾3.3s, p⫽.008) and ACMI (7.7⫾4.9s, p⫽.008). The WOLF was quicker to reach the posterior middle pole (7.3⫾4.0s) than the OLY (14.9⫾13.1s, p⫽.036), STRYK (14.7⫾14.3, p⫽.056) and ACMI (12.7⫾14.0s,p⫽.115). Subjectively, 6 of 8 endoscopists stated that the WOLF was the superior endoscope with regards to ease of manipulation, while 5 of 8 stated that the OLY was the most difficult. Of note, all 8 endoscopists had more clinical experience with the OLY than the other three endoscopes tested. Conclusions: In a model of a moderately hydronephrotic kidney with long infundibulum and limited ability to perform passive secondary deflection, endoscopes with exaggerated active deflection outmanoeuvred the Olympus URF-P3. The Wolf Viper proved superior with regards to manipulation in the hands of experienced endoscopists.

MP-05.06 The effect of impaction on the outcome of treatment of pelvic kidney stones: Comparing shock wave lithotripsy and percutaneous nephrolithotomy Basiri A, Ziaee S, Hosseini Moghaddam S, Hosseini SM, Danesh A, Sharifi Aghdas F Urology and Nephrology Research Center, Shaheed Beheshti University of Medical Sciences, Tehran, Iran Introduction: The efficacy of therapeutic options in treatment of “impacted kidney stones” which completely obstruct urinary flow, are not clearly determined. Our objective was to compare the efficacy of SWL vs. PCNL in treatment of renal “impacted stones”. Methods: In this quasi-experimental study 75 non-impacted renal stones (hydronephrosis grade 1-2) treated using PCNL (group A, 31 patients) or SWL (group B , 44 patients) and 87 renal impacted stones (hydronephrosis grade 3-4) treated using PCNL (group C, 54 case) or SWL (group D, 33 cases) were included. Stone free defined as no or less than 4 mm remnant. Results: Twenty-five cases of group A (80.6%) and 33 cases of group B (75%) became stone - free (P⫽ 0.6). On the other hand, 47 patients of group C (87%) and 12(36.4%) of group D got stone - free (P⫽ 0.004). Although comparison of outcome between group A and C showed non- significant difference (P⫽ 0.9), the

UROLOGY 68 (Supplement 5A), November 2006