Ureteral Atresia Research Articles

Laparoscopic nephroureterectomy for dysplastic kidney in children: an initial experience.

Laparoscopic nephroureterectomy for dysplastic kidney is now becoming a widely accepted procedure. We report here our initial experience with laparoscopic nephroureterectomy in four girls. Between 1993 and 1999, laparoscopic nephroureterectomy was performed in four girls (mean age 5.3 years). Three patients had an ectopic dysplastic kidney with ectopic ureter, and one patient had hydronephrosis with megaureter due to distal ureteral atresia of the upper moiety in a duplicated dysplastic kidney. The transperitoneal approach was used in all cases. Mean operative time was 195 min (range 150-266). Blood loss was minimal. All operations were completed successfully and there were no intraoperative or postoperative complications except for subcutaneous emphysema in one patient (case 4). Postoperative analgesia was used in three patients and administered in the form of diclofenac sodium suppositories 12.5 mg (cases 1 and 2) or acetaminophen suppositories 50 mg (case 3) for 1-2 days. One patient did not require any analgesia (case 4). Oral fluid intake was resumed on the first postoperative day and ambulation began within 1-3 days (mean 1.6, cases 1, 2 and 3) and 6 days (case 4). All children returned to normal activity within 3-6 days of surgery. Mean postoperative hospital stay was 7.3 days. All cases had uneventful courses after discharge. Laparoscopic nephroureterectomy can be performed safely, with minimal postoperative pain, excellent cosmetic results and early ambulation. We advocate the use of laparoscopy for the diagnosis and treatment of dysplastic kidney with ectopic ureter.

Renal anomalies in the VATER animal model

Background Purpose: Renal anomalies are a prominent feature of the VATER association. Administration of Adriamycin to timed-pregnant rats resulted in a spectrum of anomalies similar to the human VATER association. The aim of this study is to describe the renal anomalies in the Adriamycin animal model. Methods: Timed-pregnant Sprague-Dawley rats were injected with Adriamycin intraperitoneally at a dose of 2 mg/kg on days 6 through 9 of gestation. Full-term fetuses were fixed in Bouin's solution and serial transverse sections were analyzed by light microscopy. All specimens were compared with suitable controls. Results: In experimental animals, renal anomalies were found in 98% of the examined fetuses. Bilateral hydroureteronephrosis with kinking of the ureters was obvious. Ureteric atresia led to obstructive uropathy. Bladder agenesis occurred in all experimental animals. Mesonephric ducts were seen joining a proximally blind-ending urethra in male animals. In females both paramesonephric ducts ended blindly after joining each other, and this resulted in vaginal atresia. In association with imperforate anus, a recto-urethral and a recto-urogenital fistula was seen in male and female fetuses, respectively. Conclusions: Bladder agenesis was an important feature in the Adriamycin animal model. Bilateral hydronephrosis resulted from blind-ending ureters. J Pediatr Surg 36:1693-1697. Copyright © 2001 by W.B. Saunders Company.

Congenital giant megaureter: First neonatal case

The authors report the first neonatal presentation of a congenital giant megaureter (CGM), a very rare unilateral urinary anomaly, which is defined as “a ureter whose lumen is congenitally, focally and segmentally dilated to more than 10 times the normal diameter, in presence of normal bladder volume and function.” The definition of CGM is purely descriptive; it can be secondary to several different diseases, and in the series of 21 CGM (12 in duplex system) reported by Chen-Ju Huang, the morphology of the distal ureter varied from a near normal caliber to a ureteral stenosis, a ureterocele or a complete ureteral atresia. J Pediatr Surg 36:944-945. Copyright © 2001 by W.B. Saunders Company.

Unilateral Renal Agenesis May Result From in Utero Regression of Multicystic Renal Dysplasia

Renal agenesis is generally thought to result from a lack of induction of the metanephric blastema by the ureteral bud, which may be secondary to ureteral bud maldevelopment and/or to a problem with the formation of the mesonephric duct. Multicystic dysplasia is thought to result from early ureteral obstruction as evidenced by the high frequency of associated proximal ureteral atresia. The recent obstetrical practice of large scale screening of large numbers of fetuses with sonography has resulted in a significant increase in the detection of this and other genitourinary anomalies. These findings have contributed to our understanding of the natural history of many of these malformations, resulting in ongoing reassessment and refinement of current management modalities. Thus, it is now well established that a significant number of multicystic dysplastic kidneys, initially detected in utero and followed postnatally, involute and disappear with time.We report the unequivocal presence of unilateral multicystic dysplasia detected during maternal sonography in 3 fetuses, which could not be seen on subsequent studies during the fetal or immediate postnatal period. To our knowledge, these cases constitute the first report of complete in utero regression of multicystic kidneys. This novel observation indicates that some cases of unilateral renal agenesis result from in utero regression of multicystic dysplastic kidneys. This phenomenon may explain the presence of an ipsilateral blind ending ureter found in some patients with unilateral renal agenesis. However, this infrequent observation does not explain all cases of renal agenesis. Thus, the etiology of renal agenesis remains multifactorial.

Analysis of WAGR deletions and related translocations with gene-specific DNA probes, using FACS-selected cell hybrids.

We used the fluorescence-activated cell sorter (FACS) to select a series of somatic cell hybrids with deleted or translocated chromosome 11 segregated from its normal homolog. Analysis of these cell hybrids with gene-specific probes and for cell-surface marker expression has allowed us to order the markers and define a smallest region of overlap (SRO) for deletions associated with the WAGR (Wilms' tumor, aniridia, genitourinary abnormalities, and mental retardation) region of chromosome 11. Two translocation breakpoints in 11p13 (one associated with familial aniridia and one with a sporadic case of congenital renal dysfunction resulting from urethral and ureteral atresia) map within this SRO.

Congenital Obstructive Uropathy and Nodular Renal Blastema

The occurrence of nodular renal blastema and renal dysplasia was determined in a retrospective study of 75 cases of congenital obstructive uropathy. Nodular renal blastema was present in 3 upper pole nephrectomy specimens removed as a consequence of nonfunction owing to ectopic ureterocele; none was dysplastic. A more differentiated type of nodular renal blastema was present in 3 other total nephrectomy specimens, bilateral involvement in a case of posterior urethral valves and unilateral nodular renal blastema associated with ureteral atresia. This subset of differentiated nodular renal blastema was associated with renal dysplasia.

Neonatal urinomas: imaging considerations.

Neonatal urinomas can be defined as encapsulated extravasations of urine occurring secondary to congenital obstructive uropathies. Since 1978, four patients with proven urinomas have been studied at the Medical University of South Carolina, three of which had posterior urethral valves and the fourth, a segmental ureteral atresia. They were classified into three major types; subcapsular, diffuse perirenal and localized perirenal. The radiologic and imaging appearances are demonstrated. We found the most efficacious approach for identification of neonatal urinomas to be renal ultrasound, voiding cystourethrography and the Tc-99m DPTA renal scintigraphy.

DISTAL URETERAL ATRESIA

Distal ureteral atresia is a rare congenital anomaly of early childhood. Despite the present day diagnostic modalities, the pre-operative diagnosis continues to elude the clinicians. A greatly increased space between the bladder and the rectum in a lateral excretory urogram, in association with renal and bladder alterations, is highly suggestive of distal ureteral atresia. An interesting case in an adult is described: its embryogenesis and the diagnostic problems are discussed.

Cystic kidney in an 8-week human embryo.

An 8-week human embryo with cystic dilation of the right renal pelvis and ampullar portions of collecting tubules was found among 2,500 conceptuses (including 76 with urogenital malformations) obtained through unduced abortion. This observation presents further evidence that some cases of renal cysts are not secondary to ureteric atresia or nonunion of primitive collecting and secretory tubules but are the primary anomaly of ureteric bud branching and nehphron induction.

Giant ectopic ureter presenting as an abdominal mass in a newborn infant

Summary A supernumerary, hugely dilated ectopic urefer filled practically the entire abdomen. The significant roentgenologic features seen were very similar to those present in children with distal ureteral atresia and marked dilatation of the blind distal segment.