Caroline D. Ames

Durability of Flexible Ureteroscopes: A Randomized, Prospective Study

PURPOSE We performed a randomized, prospective, multi-institutional study evaluating the durability of commercially available flexible ureteroscopes. MATERIALS AND METHODS A total of 192 patients were randomized to the use of 7 less than 9Fr flexible ureteroscopes, including the Storz 11274AA and Flex-X, the ACMI DUR-8 and DUR-8 Elite, Wolf models 7330.170 and 7325.172, and the Olympus URF-P3. Information about total and lower pole use time, the number and method of ureteroscope insertion, and they type and duration of accessory instrumentation was recorded. Surgeons were asked to rate the visibility and maneuverability of the instrument on a scale of 0-poor to 10-excellent. RESULTS The indication for ureteroscopy was upper tract calculi in 87% of cases. Of ureteroscope insertions 97% were performed through an access sheath. The average of number of cases before repair ranged from 3.25 for the Wolf 7325 to 14.4 for the ACMI DUR-8 Elite. Average ureteroscope operative time was statistically longer for the DUR-8 Elite (494 minutes) than for the Flex-X (p = 0.047), and the Wolf 7325 and 7330 (p = 0.001 and 0.001, respectively). Duration of use before repair for the URF-P3 (373 minutes) was statistically longer than for the Wolf 7325 and 7330 (p = 0.016 and 0.017, respectively). Minutes of use with an instrument in the working channel were significantly more with the DUR-8 Elite and the URF-P3 than the Wolf 7330 (p = 0.017 and 0.008) and 7325 (p = 0.012 and 0.005, respectively). The ureteroscope that experienced the greatest average duration of lower pole use was the URF-P3, while the shortest was the Wolf 7325 (103 vs 20 minutes, p = 0.005). Average minutes of laser use before breakage was significantly longer for the DUR-8 Elite than for the Wolf 7325 (110 vs 21 minutes, p = 0.021) and 7330 (24 minutes, p = 0.025). CONCLUSIONS Currently available less than 9Fr flexible ureteroscopes remain fragile instruments. The DUR-8 Elite and Olympus URF-P3 proved to be the most durable devices.

Longterm Changes in Creatinine Clearance after Laparoscopic Renal Surgery

BACKGROUND Controversy exists about the impact of ischemia on renal function. We evaluated the creatinine clearance of patients having undergone laparoscopic renal extirpative and ablative surgery. STUDY DESIGN The records of patients undergoing laparoscopic procedures for renal masses from February 2000 to March 2004 were examined. Creatinine clearance (CrCl) for each patient was determined using the Cockcroft-Gault equation and ideal body weight. We compared CrCl changes of patients undergoing laparoscopic partial nephrectomy (without renal ischemia [LPN-none], with warm ischemia [LPN-warm], and with cold ischemia [LPN-cold]) with patients undergoing laparoscopic radical nephrectomy (LRN) and laparoscopic cryoablation. Patients predisposed to medical renal disease were substratified and evaluated. RESULTS All patients who underwent LRN or LPN-warm sustained a significant drop in CrCl on the first postoperative day, compared with patients who had LPN without ischemia or cryoablation (p < 0.01). The CrCl decrease correlated directly with warm ischemia time. Six months postoperatively, CrCl changes were no longer significant. Patients with medical renal disease risk factors were more likely to sustain longterm (1 year postoperatively) renal damage if they had renal ischemia, trending toward statistical significance. CONCLUSIONS Ischemia causes acute renal damage, which is apparently reversible in patients without evidence of medical renal disease. Patients with known medical renal disease have substantial longterm changes in renal function associated with unilateral renal ischemia. Considering the insensitivity of creatinine-based renal function metrics, only eliminating ischemic time will realize the goal of maximal nephron preservation, particularly in patients with preexisting medical renal disease.

Correlation of ureteric length with anthropometric variables of surface body habitus

Authors from the USA describe a method of correlating anthropometric variables of body habitus with ureteric length; they found height to be the variable that correlated most closely with ureteric length, but ureteric length was nevertheless difficult to predict.

Evaluation of surgical performance with standard rigid and flexible-tip laparoscopes

BackgroundFlexible-tip laparoscopes have recently been introduced into clinical practice, with the goal of improving surgeon performance during complex laparoscopic procedures. We used objective and subjective performance parameters to compare standard rigid 0° and 30° lens laparoscopes two flexible-tip laparoscopes in an in vitro model.MethodsTwenty-nine subjects with varied levels of surgical experience performed complex laparoscopic tasks in three different models simulating (a) prostate dissection from the rectum, (b) cystic duct clipping, and (c) distal posterior rectum dissection. Each task was performed using two Storz rigid laparoscopes (0° and 30°) and two flexible-tip laparoscopes, the Olympus LTF-V3 and the Fujinon EL2-TF310. The sequence of application of the two flexible-tip laparoscopes was randomized. In each case, an experienced laparoscopic camera driver controlled the field of vision. Time to complete each task, operative precision, and subjective surgeon rating scores were compared. Statistical analysis was performed with analysis of variance (ANOVA) and a two-sided fisher’s exact test.ResultsIn all three models, the flexible laparoscopes offered no advantage in terms of procedure time, surgical precision, or subjective surgeon rating score when compared with the 30° lens rigid laparoscope. The 30° rigid lens laparoscope and the two flexible-tip laparoscopes were superior to the 0° lens rigid laparoscope for all parameters evaluated, with the exception of subjective rating in the cystic duct model and procedure time in the colorectal model.ConclusionIn this in vitro experimental model, the flexible-tip laparoscopes found to have no advantage over the standard rigid 30° lens laparoscope. These models were validated, as the 0° lens rigid laparoscope was surpassed by the 30° lens rigid laparoscope and the flexible-tip laparoscopes. Both flexible-tip laparoscopes produced similar results and excellent image quality, but some experience is required before their smooth application can be achieved.