The impact of measuring split kidney function on post-donation kidney function: A retrospective cohort study.

BACKGROUND: Studies have reported agreement between computed tomography (CT) and renography for the determination of split kidney function. However, their correlation with post-donation kidney function remains unclear. We compared CT measurements with renography in assessment of split kidney function (SKF) and their correlations with post-donation kidney function. METHODS: A single-centre, retrospective cohort study of 248 donors from January 1, 2009-July 31, 2019 were assessed. Pearson correlations were used to assess post-donation kidney function with renography and CT-based measurements. Furthermore, we examined high risk groups with SKF difference greater than 10% on renography and donors with post-donation eGFR less than 60 mL/min/1.73m2. RESULTS: 62% of donors were women with a mean (standard deviation) pre-donation eGFR 99 (20) and post-donation eGFR 67 (22) mL/min/1.73m2 at 31 months of follow-up. Post-donation kidney function was poorly correlated with both CT-based measurements and renography, including the subgroup of donors with post-donation eGFR less than 60 mL/min/1.73m2 (r less than 0.4 for all). There was agreement between CT-based measurements and renography for SKF determination (Bland-Altman agreement [bias, 95% limits of agreement] for renography vs: CT volume, 0.76%, -7.60-9.15%; modified ellipsoid,1.01%, -8.38-10.42%; CC dimension, 0.44%, -7.06-7.94); however, CT missed SKF greater than 10% found by renography in 20 out 26 (77%) of donors. CONCLUSIONS: In a single centre study of 248 living donors, we found no correlation between CT or renography and post-donation eGFR. Further research is needed to determine optimal ways to predict remaining kidney function after donation.

Effect of pneumoperitoneum on renal tissue oxygenation and blood flow in a rat model.

OBJECTIVES: To determine the correlation between the renal blood flow (RBF) and tissue oxygenation (PO(2)) at varying intra-abdominal pressures (IAPs) and to compare the effects on renal blood flow from carbon dioxide-induced pneumoperitoneum. METHODS: Carbon dioxide pneumoperitoneum was established in Sprague-Dawley rats (n = 6). Licox oxygen/temperature tissue probes were laparoscopically inserted into the renal parenchyma, with the renal PO(2) and RBF recorded every 30 seconds while the IAP was gradually increased. Microprobes measuring the RBF, mean arterial pressures and serum pH were placed into the parenchyma to compare the effects of carbon dioxide pneumoperitoneum (n = 7) with that of open surgery (n = 6) and medical air pneumoperitoneum (n = 6). RESULTS: Renal PO(2) was inversely related to the IAP (P < .001). Despite the reduction in IAP, the renal PO(2) in the recovery phase was lower than at baseline (P = .045). The renal PO(2) and RBF changed in a virtually identical pattern at varying levels of IAP (P > .05). The RBF significantly declined with a pneumoperitoneal pressure of 15 and 20 mm Hg (P = .022), regardless of the gas used to create the pneumoperitoneum. A partial reversal of the RBF occurred with a decrease of the IAP. The RBF in the open surgical arm remained unchanged. Although both the serum pH and the mean arterial pressure were inversely proportional to the IAP (P < .001), the mean arterial pressure was depressed to the greatest extent in the medical air group (P = .02). CONCLUSIONS: These results have demonstrated that elevated IAP secondary to pneumoperitoneum causes significant renal hypoxia and decreased RBF. Additionally, this experiment has demonstrated the use of the Licox probes in monitoring the renal PO(2) and established a novel method for evaluating the effects of IAP on the kidney.

Survey of senior resident training in urologic laparoscopy, robotics and endourology surgery in Canada.

INTRODUCTION: We determined the status of Canadian training during senior residency in laparoscopic, robotic and endourologic surgery. METHODS: Fifty-six residents in their final year of urology residency training were surveyed in person in 2007 or 2008. RESULTS: All residents completed the survey. Most residents (85.7%) train at centres performing more than 50 laparoscopic procedures yearly and almost all (96.4%) believe laparoscopic radical nephrectomy is the gold standard. About 82% of residents participated in a laparoscopic partial nephrectomy in 2008, compared to 64.7% in 2007. Of the respondents, 66% have participated in a laparoscopic prostatectomy and 54% believe the procedure has promising potential. Exposure and training in robotic-assisted laparoscopic procedures seem to be increasing as 35.7% of 2008 residents have access to a surgical robot and 7% consider themselves trained in robotic-assisted procedures. Most residents (71.4%) train at centres that perform percutaneous ablation. However, 65% state the procedure is performed solely by radiologists. Percutaneous nephrolithotomy is widely performed (98.2%), but only 37.5% of residents report training in obtaining primary percutaneous renal access. Despite only 12.5% of residents ranking their laparoscopic experience as below average or poor, an increasing proportion of graduating residents are pursuing fellowships in minimally-invasive urology. CONCLUSION: Laparoscopic nephrectomy is commonly performed and is considered the standard of care by Canadian urology residents. Robotic-assisted surgery is becoming more common but will require continued evaluation by educators who will ultimately define its role in the urological residency training curriculum. Minimally-invasive surgical fellowships remain popular, as Canadian residents do not feel adequately trained in certain advanced procedures. Urologists must strive to learn and adapt to new technologies or risk losing them to other specialties.

Impact of arterial and arteriovenous renal clamping with and without intrarenal cooling on renal oxygenation and temperature in a porcine model.

BACKGROUND: As laparoscopic partial nephrectomy increases in prominence, more needs to be understood about the combined effect of the pneumoperitoneum and renal ischemia during tumor resection. The purpose of this study is to investigate the effect of combined renal hilar clamping (arterial only versus arteriovenous) and retrograde intrarenal cooling on renal temperature and oxygenation in a porcine laparoscopic partial nephrectomy model. MATERIALS AND METHODS: Under general anesthesia, laparoscopic access with intra-abdominal pressure of 15 mm Hg to the left renal hilum was obtained. Licox tissue oxygenation and temperature probes were placed into the kidney transcutaneously; measurements were taken every 30 seconds. After establishing baseline readings, either the artery alone (n=18) or the artery and vein (n=18) were clamped for 30, 60 or 90 minutes (n=12 each). During vascular clamping, retrograde, intrarenal cooling was performed with ice cold saline infused via a percutaneously placed ureteric catheter in 18 pigs. Changes in renal pO2 and temperature were analyzed with repeated measures ANCOVA in SPSS 16. RESULTS: Retrograde cooling decreased renal parenchyma to 75.8% of baseline temperature (27.9 degrees C) within 15 minutes. There were no differences in cooling whether arterial or arteriovenous clamping was used (p=0.79). In uncooled animals, there was no significant difference in the decrease in renal pO2 during the clamp phase (p=0.18) or during the recovery phase (p=0.52). During the recovery phase, renal pO2 in uncooled animals was significantly higher than in those who received cooling (p=0.01). Animals who underwent hilar clamping for extended periods (60 and 90 min) had a slower recovery of renal pO2 to baseline than those with hilar clamping for 30 minutes (p=0.04) CONCLUSION: Retrograde intrarenal cooling can reliably cool the porcine kidney to 28 degrees C, regardless of whether arterial or arteriovenous clamping is used. Renal pO2 is not significantly different between animals that undergo artery only versus en bloc hilar clamping. Pigs that were provided with retrograde cooling had a slower return of pO2 to baseline following release of hilar clamps, possibly due to hypothermic vasospasm. Clamp durations greater than 60 minutes were also associated with slower return of renal oxygenation to baseline.

Practical comparison of four nitinol stone baskets.

BACKGROUND AND PURPOSE: The use of stone baskets for repositioning of stones or removal of fragment in conjunction with ureterorenoscopy has become widespread. We tested the performance of the ACMI Sur-Catch NT, Bard Dimension, Boston Scientific Zero-tip, and Cook N-Circle in a pig kidney model of flexible ureterorenoscopy. MATERIALS AND METHODS: Opening characteristics of the basket were measured with mechanical calipers at 1-mm increments and compared with published reports to ensure the tested baskets were representative. Pig kidneys were placed in a basin and the ureters secured with a suture to a weight for stability. Flexible renoscopy was performed using a 16F flexible cystonephroscope. An 8-mm calculus was placed in the lower pole. Using each of four designs, the time necessary to grasp the stone, time to release the stone, and total time to move a stone from the lower-pole calix to the upper-pole were recorded. Total time experiments were repeated six times with each basket by three surgeons for a total of 18 attempts, and catch-and-release experiments were repeated six times by four surgeons for a total of 24 attempts per basket. RESULTS: The Sur-Catch was significantly slower for catch and release (P < 0.001) and total time; P < 0.05) compared with all other baskets. There were no differences between the other baskets in either catch, release, or total times. There was no difference between surgeons (P < 0.0634) or between attempts one through six (P = 0.538). CONCLUSIONS: Baskets with added complexity of the wire configurations (Sur-Catch) or a deflectable-wire mechanism (Dimension) offer no advantages and may slow capture and release of stones.

Comparison of Peditrol irrigation device and common methods of irrigation.

BACKGROUND AND PURPOSE: The Peditrol is a novel hands-free irrigation device that delivers a bolus of irrigant through the ureteroscope when the foot pedal is deployed. The purpose of this study was to compare the flow and pressures created by the Peditrol with those of commonly used methods of irrigation. MATERIALS AND METHODS: Flows through a flexible 6.9F Olympus ureteroscope (F-URS) and a 7.5F semirigid ACMI ureteroscope (S-URS) were measured in duplicate with the working channel empty and with a 2.2F Nitinol basket or a laser fiber in the working port. Irrigant flow was pressurized by gravity drainage at 100 cm H(2)O (GI), pressurized irrigant bag at 300 cm H(2)O (PI), handheld 60-cc syringe (HS), and the Peditrol. A 20-gauge angiocatheter was placed through the parenchyma into the renal pelvis of an ex-vivo cadaveric porcine kidney and attached to a pressure transducer. Pressures were measured in triplicate using the same irrigation techniques. RESULTS: With a basket or 200-microm laser fiber in the working port of the F-URS, Peditrol mean flows were superior to those of PI (3.3 and 6.3 times, respectively; P < 0.001) but similar to those of HS (0.7 to 1.1 times). All irrigation types resulted in intrarenal pressures greater than gravity irrigation (P < 0.05). The Peditrol demonstrated intrapelvic pressures <40 cm H(2)O when used with a 12/14F ureteral access sheath (AS). Without an AS, the intrapelvic pressure reached 92 cm H(2)O, similar to the pressures reached with the S-URS under various irrigation conditions (84-287 cm H(2)O) and comparable to the HS method through the F-URS (97 cm H(2)O). CONCLUSIONS: The Peditrol irrigation device generates superior flow through an F-URS compared with GI or PI, particularly with an instrument in the working port. Intrarenal pressures when used with an F-URS and AS are low. When an AS is not used, the intrarenal pressure is similar to or lower than pressures obtained using an S-URS with different irrigation modalities.

Semirigid ureteroscopy of the proximal ureter can be aided by external lower-abdominal pressure.

BACKGROUND AND PURPOSE: Smaller semirigid ureteroscopes with large working channels and excellent optics are widely available. Ureteroscopic treatment of upper-ureteral stones has become increasingly popular, although flexible ureteroscopy is more frequently the method of choice. Access to the upper ureter with a semirigid ureteroscope (SR-URS) can be challenging and hazardous, especially when negotiating the iliac vessels. We sought to determine whether lower-abdominal pressure (LAP) facilitated SR-URS access to the upper ureter for safe laser lithotripsy. PATIENTS AND METHODS: Thirty-two consecutive patients who underwent ureteroscopic management of upper- ureteral stones were evaluated. Twenty-four (75%) were male; seventeen (53%) had a right-sided stone. The mean largest stone diameter was 10.2 +/- 4.6 mm. These 32 patients were compared with a matched cohort of patients who underwent SR-URS procedures without the use of LAP. RESULTS: Access to the upper ureter was possible in 30 patients (94%). The LAP was helpful in 18 patients (56%): it facilitated passage of the SR-URS in 16 patients (50%) and laser fiber placement in 11 cases (34%). Access to the upper ureter was possible in all women. The mean operative time was 54 minutes in the LAP group and 75 minutes in the matched cohort without LAP (P = 0.026). There were no significant deformities of the SR-URS and no complications. CONCLUSIONS: Contrary to popular practice, the upper ureter can be accessed safely and efficiently with a 7.5F SR-URS in nearly all patients. Lower-abdominal pressure can be helpful to negotiate passage of the endoscope over the iliac vessels or to place the laser fiber on stones.

Laparoscopic simple prostatectomy.

Classically, surgical options for very large prostate glands, not amenable to transurethral resection, include suprapubic or retropubic simple prostatectomy and Holmium laser enucleation of the prostate (HoLEP). We present a case managed with a laparoscopic simple prostatectomy. Technical considerations are discussed as well as possible advantages of this approach including decreased blood loss, faster patient recovery and improved visualization.