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.

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.

Intraoperative laparoscopic renal ultrasonography: use in advanced laparoscopic renal surgery.

OBJECTIVES: To highlight the use of intraoperative laparoscopic ultrasonography (ILUS) in complex renal surgery, as well its impact on management. ILUS has been used to facilitate advanced laparoscopic surgery, but only limited descriptions of the indications for its use have been published. METHODS: All patients undergoing laparoscopic renal procedures requiring ILUS from October 2001 to March 2005 were reviewed. A total of 50 cases, including 35 partial nephrectomies, cryoablation of 6 renal tumors, 6 radical nephrectomies, 2 perinephric explorations, and 1 resection of a renal artery aneurysm were assessed by ILUS. RESULTS: The average tumor size in the patients undergoing laparoscopic partial nephrectomy was 3.1 cm (range 1.4 to 8.0), and all margins were negative. Also, a previously unidentified satellite lesion was found in 1 patient. ILUS was essential in assessing iceball formation during laparoscopic renal cryotherapy. ILUS also proved useful in defining the anatomy during laparoscopic perinephric exploration, assessing renal vein thrombi during laparoscopic nephrectomy, and evaluating renal perfusion during laparoscopic renal artery aneurysm repair. CONCLUSIONS: ILUS can be extremely useful in advanced laparoscopic renal surgery. In a number of situations, it is an essential surgical tool. With expanding indications for laparoscopic surgery, the indications for ILUS continue to grow.

Laparoscopic management of advanced renal cell carcinoma with level I renal vein thrombus.

OBJECTIVES: To present our series of laparoscopic radical nephrectomy in patients with level I tumor thrombus. The existence of renal vein tumor thrombus presents a technical challenge in securing hilar control during the resection of a renal mass. To our knowledge, this experience represents one of the largest series of laparoscopic nephrectomy for renal cell carcinoma associated with a macroscopic renal vein thrombus. METHODS: From April 2002 to June 2004, 12 patients (8 men and 4 women) were diagnosed with renal masses. In addition to computed tomography, cavography and magnetic resonance imaging were used to determine the levels of tumor thrombi preoperatively in those who had suspicious involvement of the renal vein on computed tomography. RESULTS: Laparoscopic nephrectomy was performed in a standard fashion. Hand-assisted laparoscopic nephrectomy was used in 6 cases involving large tumors with bulky hilar adenopathy. All renal veins were stapled using an endoscopic vascular stapler. Intraoperative laparoscopic ultrasonography was used to delineate the extent of the vein thrombus in 4 cases to enable proper stapler positioning. No intraoperative complications occurred, and 2 cases were electively converted to open nephrectomy. The postoperative narcotic requirements and hospitalization times were low. Pathologic examination of the tumor specimens demonstrated negative resection margins in all patients. CONCLUSIONS: In carefully selected patients, laparoscopic resection of renal masses with level I renal vein thrombi is feasible. Because of technical considerations that may be identified intraoperatively, early conversion to open nephrectomy should be anticipated. Long-term results regarding oncologic control continue to be assessed.

The laparoscopic experience of recently trained Canadian urologists.

OBJECTIVE: While laparoscopy represents an increasingly important aspect of operative urology, the experience of Canadian urology trainees is poorly defined. The purpose of this study was to determine the level of laparoscopic training of Canadian urology trainees during residency as well as their comfort level with various laparoscopic techniques. METHODS: An e-mail-and web-based questionnaire was administered to the two most recent cohorts of Canadian-trained urologists (residencies completed in 2003 or 2004). A total of 50 questionnaires were sent. Overall laparoscopic experience and experience with specific laparoscopic tasks (e.g. colonic mobilization) were assessed. Subjects also reported on their relative comfort level (Likert scale of 1 to 5) with various laparoscopic procedures and tasks. Finally, attitudes towards the future role of laparoscopy in the practice of urology were determined. RESULTS: Thirty-six individuals (72%) responded to the questionnaire. Of the respondents, 28 (78%) were performing fellowships; of those pursuing fellowship training, 13 (36%) involved laparoscopy. Thirty-five respondents (97%) had received some laparoscopic exposure during residency; 29 (81%) had mobilized the colon, spleen or liver and 27 (75%) had dissected the renal vessels. Only 7 out of 33 respondents (21%) felt that their residency adequately prepared them to perform laparoscopy independently. There were no significant differences between the responses of the two cohorts. CONCLUSION: Most Canadian urology trainees are being exposed to laparoscopy, but more exposure is required in order to perform laparoscopy in practice. Many residents still require fellowship training to become facile in laparoscopy.

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.

Erectile dysfunction: management update.

Dramatic advances in the management of erectile dysfunction have occurred over the past decade. Oral therapy with vasoactive agents has emerged as first-line treatment and has transformed both the manner in which the public views erectile dysfunction and the way health care providers deliver care. Whereas an extensive investigation was previously common in the management of erectile dysfunction, recent treatment guidelines promote a more minimalist, goal-oriented approach. In this article, we review the physiology of erection, and the pathophysiology, diagnosis and clinical management of erectile dysfunction. We also present the existing evidence for the efficacy of 3 phosphodiesterase inhibitors, the most widely used class of agents for erectile dysfunction.