Evangelos Liatsikos

PDE5 inhibition against acute renal ischemia reperfusion injury in rats: does vardenafil offer protection?

PurposeTo evaluate the effect of vardenafil on renal function after renal ischemia–reperfusion (IR) injury (IRI) in a rat model.Materials and methodsSeventy-one Wistar rats were divided into 7 groups including (1) a vehicle-treated group, (2) a vehicle pretreated-IR group, (3–6) vardenafil pretreated-IR groups in doses of 0.02, 0.2, 2 and 20xa0μg/kg, respectively, (7) a group of IR followed by treatment with 2xa0μg/kg of vardenafil. Vardenafil or vehicle solution was administered one hour before unilateral nephrectomy and the induction of 45xa0min of ischemia on the contralateral kidney by clamping of renal pedicle. Four hours of reperfusion were allowed after renal ischemia. Studied parameters were serum creatinine, fractional excretion of sodium (FENa), and histological evaluation of renal specimens. In addition, renal tissue cGMP levels, ERK1/2 phosphorylation as well as renal function by renal scintigraphy were also evaluated.ResultsAdministration of vardenafil before the induction of ischemia resulted in a significant reduction in creatinine and FENa levels as well as in less histological lesions observed in treated kidneys in comparison with the vehicle-treated group. The underlying mechanism of cytoprotection was cGMP depended and involved the phosphorylation of ERK proteins. Renal scintigraphy confirmed that PDE5 inhibition attenuates renal IRI.ConclusionsVardenafil attenuates renal IRI. Based on similar results from relevant studies on other PDE-5 inhibitors in renal and cardiac IRI, it can be assumed that all PDE-5 inhibitors share a common mechanism of cytoprotection.

Live surgery: highly educational or harmful?

PurposeLive surgery (LS) is considered a useful teaching opportunity. The benefits must be balanced with patient safety concerns. To evaluate the rate of complications of a series of urologic LS performed by experts during the Congress Challenge in Laparoscopy and Robotics (CILR).MethodsWe present a large, multi-institution, multi-surgeon database that derives from 12 CILR events, from 2004 to 2015 with a total of 224 cases. Radical prostatectomy (RP) was the most common procedure and a selection of complex cases was noted. The primary measure was postoperative complications and use of a Postoperative Morbidity Index (PMI) to allow quantitative weighing of postoperative complications.ResultsFrom 12 events, the number of cases increased from 11 in 2004 to 27 in 2015 and a total of 27 surgeons. Of 224 cases (164 laparoscopic and 60 robotic), there were 26 (11.6%) complications: 5 grade I, 5 grade II, 3 grade IIIa, 12 grade IIIb and 1 grade V, the latter from laparoscopic cystectomy. Analysis of PMI was 23 times higher from cystectomy compared to RP.ConclusionsIn the setting of live surgery, the overall rate of complications is low considering the complexity of surgeries. The PMI is not higher in more complex procedures, whereas RP seems very safe.

Optical coherence tomography provides images similar to histology and allows the performance of extensive measurements of drug-eluting metal stents in animal ureters

Optical coherence tomography (OCT) images and histology images of metal stents (MSs) inserted in animal ureters were compared, and the reliability of an OCT-based automated method for the performance of quantitative evaluation of ureteral MSs was evaluated. A zotarolimus-eluting metal stent (ZES) and a bare metal stent (BMS) were inserted in each ureter of ten pigs and six rabbits. OCT was performed in unobstructed stented ureters. Histopathologic examination of the stented ureters embedded in glycol-methacrylate took place. Quadrants of OCT images were compared to their respective histologic images by employing two independent observers who delineated different layers in the quadrants of OCT images and correlated them to the respective histologic quadrants. Manual (integrated OCT device software) and automated measurements of the OCT images using an automated strut detection method were compared. The observers highly agreed on the delineation of urothelium from the lamina propria and the lamina propria from the muscle layer of the ureteral wall. The algorithm measurements were similar to the manual measurements, and the algorithm proved to be reliable in the evaluation of ureteral MSs. Significantly higher endothelial hyperplasia of the BMSs in comparison to the ZESs was also quantitatively demonstrated by the strut detection method. OCT proved to be a reliable method for the evaluation of ureteral MSs. OCT provided images of the stented ureteral lumen similar to light microscopy quality. Measurements of the stented ureter are reliably performed by the automated strut detection method.

Metal stents in the upper urinary tract

Abstract Metal stents have been used in urology after their initial successful application in other organ systems. The indications for metal stents include malignant and benign ureteral obstruction. Several types of metal stents have been introduced and used in clinical practice with satisfactory results. Immediate as well as long-term ureteral patency can be successfully established using metal stents. Complications include encrustation, migration and endothelial hyperplasia. Future investigations will focus on the development of metal stents with fewer complications.

Nuances of Extraperitoneal Laparoscopy

The retroperitoneal and extraperitoneal pelvic approach are related with advantages in terms of avoiding intraperitoneal adhesions from previous surgery, formation of new intraperitoneal adhesions and tamponade of any urine or blood leakage extraperitoneally. Retroperitoneal renal surgery has been associated with shorter operative and hospitalization times. In the case of partial nephrectomy, the retroperitoneal approach is preferred by the majority of the surgeons for the management of tumors located at the posterior surface of the kidney. The anatomy related to the retroperitoneal and extraperitoneal approach does not represent a challenge to the urologist. Some important tricks in the trocar placement and anatomical orientation should be considered. Every surgeon should have knowledge of these advantages and disadvantages as well as the anatomy in order to set the appropriate indication and to perform surgery without access related difficulties.

Septic Complications During Percutaneous Nephrolithotomy (PCNL)

Percutaneous nephrolithotomy (PCNL) is a milestone for the removal of renal stones for three decades already. Since the first introduction of the technique in 1976, various improvements have been proposed. The indications of the procedure were limited due to the introduction of extracorporeal shock wave lithotripsy (ESWL) in the 1980s. Clinical experience with ESWL revealed the limitations of the technique, and the role of PCNL in the management of renal stones was redefined. The current indications for PCNL include large, hard infected stones, obstruction-related stones, ESWL failures, and stones related with anatomical variations. In addition, improvements in instruments such as flexible nephroscopes, ureteroscopes, and lithotriptors (holmium/yttrium-aluminum-garnet laser, combination of ultrasound and pneumatic technology) contributed to the current high stone-free rates of PCNL which are higher than 90 %. Flexible nephroscopes allowed the disintegration and removal of stones in calyces not accessible by the rigid nephroscopes, while advanced lithotriptors enabled the management of very hard stones.