Renal Outflow Obstruction Research Articles

Laparoscopic pyeloplasty: the standard of care for ureteropelvic junction obstruction

Open pyeloplasty has been the gold standard treatment for ureteropelvic junction obstruction (UPJO). Endopyelotomy, in spite of its inferior effectiveness, was sometimes preferred in select patients owing to its less invasive nature. Fortunately, over the past 2 decades a superior minimally invasive treatment has emerged with success rates equivalent to open pyeloplasty and complication rates equivalent to endopyelotomy. It is for good reason that laparoscopic pyeloplasty has become the new standard of care for the treatment of UPJO. Ureteropelvic junction obstruction is marked by renal outflow obstruction and may be asymptomatic or result in pain and complications, such as renal failure, pyelonephritis and calculus formation. Surgical management of UPJO aims to provide symptomatic relief and preserve remaining renal function. Today, treatment usually consists of either laparoscopic pyeloplasty or endopyelotomy. Its effectiveness, versatility and safety make laparoscopic pyeloplasty the optimal treatment for UPJO in virtually all circumstances.

IMAGING DIAGNOSIS—ULTRASOUND‐GUIDED ETHANOL SCLEROTHERAPY FOR A SIMPLE RENAL CYST

Solitary renal cysts are benign and in the majority of instances asymptomatic and do not require treatment. Nevertheless, treatment may be required if abdominal discomfort or pain, hypertension, infection or renal outflow obstruction occur. Under these circumstances, percutaneous management of the cyst is the easiest and fastest procedure, and no major complications are generally encountered. In this report we describe a patient with a solitary renal cyst treated successfully by a single injection of ethanol into the cyst. The sonographic appearance of the cyst changed from a well-defined hypoechoic structure to an ill-defined hyperechoic region. Canine renal cysts may be successfully managed in some instances by a single ethanol injection.

Increased severity of renal ischemia-reperfusion injury with venous clamping compared to arterial clamping in a rat model

Arterial inflow occlusion is a well-known mechanism of renal injury during major vascular surgery. In contrast, renal injury from venous outflow obstruction is poorly understood. The goal of this study was to examine the injury pattern of renal venous outflow obstruction, compare this with the traditional model of arterial occlusion, and examine possible mechanisms. Male Fisher rats were used for the renal warm ischemia model. Twenty-five minutes of renal ischemia was induced by selectively occluding either the renal artery or vein. After 24 h of reperfusion, whole blood and kidney tissue were collected for further analysis. Serum creatinine (SCr) concentrations taken 24 h after reperfusion were significantly greater in the venous occlusion group (V) when compared to the arterial group (A). While histology did not demonstrate significant differences in extent of necrosis between both groups, a stronger inflammatory response resulted from venous occlusion. Specifically, significantly greater MCP-1 mRNA and significantly greater MCP-1, TNF-alpha, and HO-1 protein levels were found in the venous group, while no differences in MIP-2, ICAM-1, and VCAM-1 mRNA expression existed between A and V. Further analysis demonstrated presence of increased cleaved caspase-3 protein in the artery group than in the venous group. Venous renal outflow obstruction results in more severe functional renal injury when compared to arterial inflow occlusion. Macrophage activation and neutrophilic infiltration appear to be exaggerated during venous occlusion.

The Effects of Double J Stents on Renal Pelvic Dynamics in the Pig

Intra-pelvic pressure and peristaltic activity were measured before and during diuresis in 26 minipigs, immediately, one week and three weeks following ureteric intubation with 5 and 6F polyethylene double J stents. Changes in these dynamic parameters were seen which indicate that these stents caused renal outflow obstruction. The severity of this obstruction appears dependent upon the size of the catheter and the temporal length of intubation. This study indicates that double J stents provide sub-optimal drainage of the renal pelvis and damaged ureter. (J. Urol., 140:637–641, 1988)

OBSTRUCTIVE NEPHROPATHY: SUCCESSFUL EVALUATION WITH RADIONUCLIDES

A non-invasive test of nephron function, the renal parenchymal transit time (P.T.T.) index, is shown to be as accurate as antegrade pressure measurements in diagnosis of renal outflow obstruction. It is more sensitive than conventional methods of demonstrating the associated obstructive nephropathy. P.T.T. is useful in following the effects of surgery, or of temporising, in patients with confirmed or potential outflow tract obstruction. Renal radionuclide P.T.T. analysis gives the functional information essential for the management of patients in whom intravenous urography reveals a dilated renal pelvis.

Abnormal ureteral peristaltic activity during pregnancy.

Ureteral peristalsis in five pregnant patients with signs of acute renal outflow obstruction was studied with the aid of a new technique for recording intraureteral pressure (ureterometry). With this technique it is possible to record the intraureteral pressure at three different levels in the ureter simultaneously. The rate of propagation and direction of the peristaltic waves can thus be determined. Retrograd peristalsis was found in three of the five patients and in one patient and in one patient no peristaltic activity was present at all. The fifth patient demonstrated normal antegrade peristalsis. The findings at renography in the acute stage were in accordance with the ureterometric data.