The kidney in congenital ureteropelvic junction obstruction: a spectrum from normal to nephrectomy.

PURPOSE: Our recent studies of renal histology in congenital ureteropelvic obstruction cases prompted us to review the literature in this regard, focusing on issues of development, normal variation, clinicopathological correlations and pathogenesis. MATERIALS AND METHODS: The period from 1971 to 2006 was analyzed, including all relevant articles, which were critically reviewed. RESULTS: There have been many studies encompassing the entity of ureteropelvic junction obstruction that include clinical findings, radiographic imaging, pathological examination of ureteropelvic junction obstruction per se and renal biopsies during pyeloplasty procedures. We synthesized this information in a cohesive review with a proposed classification. CONCLUSIONS: Congenital ureteropelvic junction obstruction is a spectrum that ranges from the radiological demonstration of apparent physiological ureteropelvic junction obstruction to a disordered ureteropelvic junction, characterized by smooth muscle hypertrophy and fibrosis associated with renal parenchymal changes that may necessitate pyeloplasty or nephrectomy. However, renal biopsies in patients in whom pyeloplasty is done show in most of them relatively well maintained parenchyma, in which overt changes are mainly glomerular. More subtle alterations have been described that relate to shifts in proximal-to-distal tubular ratios. Extreme thinning of the renal parenchyma can occur with only limited tubulointerstitial injury. Recently ureteropelvic junction obstruction was described in a series of genetically altered animals and placed in a more global context, ie CAKUT (congenital abnormalities of the kidney and urinary tract).

Application of renal Doppler sonography in the diagnosis of obstructive uropathy in patients with spinal cord injury.

OBJECTIVES: To assess renal resistive index (RI) changes in patients with spinal cord injury (SCI) who have obstructive uropathy and to determine if an RI of 0.7 or more is useful in identifying such patients. DESIGN: Prospective cross-sectional study. SETTING: Rehabilitation hospital affiliated with a medical university. PARTICIPANTS: A convenience sample of 99 kidneys of 51 SCI patients (38 men, 13 women; mean age, 38.8+/-14.0 y) with neuropathic bladder dysfunction. INTERVENTIONS: Ultrasonic examination to assess the degree of hydronephrosis, Doppler sonography to calculate renal vascular RIs, and radioisotopic renography to assess renal function and to determine excretory curves. Kidneys were assigned to control or obstructive uropathy groups, and RIs were compared for statistical significance (Student t test) and to assess whether an RI of 0.7 is a distinguishing criterion. MAIN OUTCOME MEASURES: RI and sensitivity. RESULTS: Average RIs were .58+/-.07 in the control group (71 kidneys) and .65+/-.08 in the uropathy group (28 kidneys) (P<.001). The sensitivity of using an RI of 0.7 or more to identify patients with obstructive uropathy was 39%. The c statistic of the receiver operating characteristic curve was .72. CONCLUSIONS: RIs increased in SCI patients with obstructive uropathy. In patients with SCI, urinary findings fit the chronic partial obstruction pattern. A renal RI of 0.7 or more was a poor indicator of obstructive uropathy in such patients.

Obstructive ureterocele-an ongoing challenge.

Ureterocele is a cystic dilatation of the intravesical ureter that is most commonly observed in females and children, and usually affects the upper moiety of a complete pyeloureteral duplication. According to their position, ureteroceles are divided into intravesical, when the ureterocele is completely contained inside the bladder, and extravesical when part of the cyst extends to the urethra or bladder neck. Most ureteroceles are diagnosed in utero or immediately after birth during an echographic screening of renal malformations. Severe, febrile urinary tract infection is the most common postnatal presentation of ureteroceles, but they may, rarely, prolapse and acutely obstruct the bladder outlet. Once an ureterocele is identified sonographically, a voiding cystourethrogram to detect vesicoureteral reflux (VUR) and a 99m-technetium dimercapto-succinic acid renal scan to evaluate the function of the different portions of the kidney are mandatory. VUR in the lower pole is observed in 50% of cases and in the contralateral kidney in 25%. Simple endoscopic puncture of the ureterocele has recently been advocated as an emergency therapy for infected or obstructing ureteroceles and as an elective therapy for intravesical ureteroceles. The rate of additional surgery after elective endoscopic puncture of an orthotopic ureterocele ranges from 7 to 23%. Treatment of ectopic ureteroceles is more challenging and both endoscopic puncture and upper pole partial nephrectomy frequently require additional surgery at the bladder level. The reoperation rate after endoscopic treatment varies from 48 to 100%. It is 15 to 20% after upper pole partial nephrectomy if VUR was absent before the operation, but is as high as 50-100% when VUR was present. Thus, endoscopic incision is appropriate as an emergency treatment or when dealing with a completely intravesical ureterocele. Upper pole partial nephrectomy is the elective treatment for an ectopic ureterocele without preoperative VUR. In an ectopic ureterocele with VUR, no matter which type of primary therapy has been chosen, a secondary procedure at the bladder level, involving ureterocele removal and reimplantation of the ureter(s), should be anticipated.

[Urinary obstruction: different radio-clinical types]. / Obstruction urinaire: les différents types radio-cliniques.

Urinary obstruction has three different clinical aspects: acute, chronic and intermittent. Imaging modalities and diagnostic strategies are different for each of them. Although the morphologic analysis is accurate for all imaging modalities, the diagnosis of hydronephrosis may not be so easy, except for major typical form. There are some pitfalls, for instance the presence of parapelvic cysts at ultrasound and difficulties for initial or minor forms. Nowadays, IVU is still in routine the best examination to assess renal function. In the near future, MRI should be able to give useful information for both morphologic and functional status and take an important role in the evaluation of urinary obstruction.

Obstructive uropathy.

Obstructive uropathy refers to the condition of obstruction to urine flow from the kidney to the bladder. Such obstruction may be acute or chronic, complete or incomplete, and unilateral or bilateral. It has many diverse causes each with their own specific features and yet each producing similar disturbances to renal function and urine flow. This paper discusses the unique role of nuclear medicine techniques in the diagnosis and management of urinary tract obstruction in current urological practice.

Ureteral obstructions and leaks after renal transplantation: outcome of percutaneous antegrade ureteral stent placement in 44 patients.

PURPOSE: To analyze the outcome of percutaneous antegrade ureteral stent placement for treatment of ureteral stenoses and leaks after renal transplantation. MATERIALS AND METHODS: Antegrade pyelography and percutaneous ureteral stent placement were performed in 45 patients with ureteral obstruction (n = 40), leak (n = 3), or both (n = 2). Obstructions were graded as mild, moderate, or complete, and as early (< or = 3 months after transplantation) or late (> 3 months). RESULTS: The outcome of stent placement was successful in 25 (57%) patients (average follow-up, 30 months). The ureteroneocystostomy (UNC) was the most common site of obstructions (22 of 41), leaks (four of five), and successful outcomes (16 of 22). Moderate obstructions were most common (29 of 41) and responded best to treatment (17 of 29). Eighteen (69%) of 26 early obstructions and five (33%) of 15 late obstructions were successfully managed percutaneously. All complications (12 of 45 patients) were minor, with infections the most common (n = 7). No mortality or allograft loss was attributable to stent placement. CONCLUSION: Ureteral stents are safe and effective for the treatment of obstructions and leaks and are particularly effective for early and UNC obstructions. These stents may also be useful for temporary drainage.

The relationship of age to pathology in pelviureteric junction obstruction.

OBJECTIVE: To ascertain the age distribution of the different pathological mechanisms which lead to the development of pelviureteric junction obstruction. METHODS: A series of 165 kidneys in 158 children who underwent pyeloplasty for pelviureteric junction obstruction were reviewed. Those 132 renal units (127 children) with uncomplicated pathology were selected for further study. The operative records were reviewed for the underlying cause of obstruction and the age at operation. RESULTS: Obstruction due to extrinsic compression by an aberrant lower pole vessel occurred in an older group (median age 67.3 mo) than those with a narrowing or angulation of the pelviureteric junction (median age 3.1 mo). CONCLUSIONS: Pelviureteric junction obstruction, secondary to a lower pole vessel presents at an older age. Doppler ultrasonography to detect a lower pole vessel may be of benefit in the management of equivocal cases of pelviureteric junction obstruction, particularly in prenatally diagnosed hydronephrosis.

[Significance and consequences of mild fetal kidney pelvis dilatation]. / Bedeutung und Konsequenzen milder fetaler Pyelondilatationen.

Even mild fetal pyelectasia is a subject to post-partal control. As fetal kidneys can easily be examined by ultrasound, different degrees of dilatation are found, but the discrimination between normal and pathological has not yet been defined. We considered any dilatation of less than 7 mm als normal. 52 fetuses were found to have a dilatation of 7 mm and more. 8 of them required post partum surgery: 2/15 classified as Grignon grade I, 3/14 as Grignon II, and 3/3 as Grignon III. Further malformations in addition to pyelectasia require a prenatal caryotyping procedure.

Classification of and techniques for the reconstitution of acquired strictures in the region of the ureteropelvic junction.

We performed percutaneous intrarenal surgery on 22 patients with acquired strictures of various degrees of severity in the region of the ureteropelvic junction. Of 17 patients with strictures through which a guide wire could be passed (type 1) 8 (47 per cent) had good or excellent long-term results. Of 4 patients with strictures that were patent radiologically but through which a guide wire could not be passed (type 2) only 1 (25 per cent) had good long-term results. The patient with a stricture that totally obliterated the lumen (type 3) suffered recurrence. We conclude that percutaneous techniques for the management of acquired strictures in the region of the ureteropelvic junction can be difficult technically and currently are most successful in the treatment of strictures of short duration that occur after pyeloplasty.