The Fate of Prenatally Diagnosed Primary Nonrefluxing Megaureter: Do We Have Reliable Predictors for Spontaneous Resolution?

doi:10.1016/j.urology.2008.02.032

Urology

Volume 72, Issue 2, August 2008, Pages 309-312

https://doi.org/10.1016/j.urology.2008.02.032 Get rights and content

Objectives

To compare predictive values of current morphologic parameters with congenital renal damage associated with severe megaureter.

Methods

A retrospective analysis was performed using records of 37 patients (50 megaureters) referred before birth for a primary megaureter. Mean follow-up was 26 months (range, 1 to 8 years).

Results

Dilatation resolved spontaneously in 46 of 50 ureters. Only 4 of 37 patients required surgery (10.8%) after a mean follow-up of 58 months (range, 32 to 80 months). Average time to resolution was 24 months (range, 1 to 82 months) and was independent from sex, side, and bilaterality. A weak correlation was found with initial anteroposterior pelvic diameter, ureteral diameter, and separate function at renogram. A significant correlation (P <0.02) was found between megaureter type and time elapsed to spontaneous resolution. As far as differential function was concerned, mean values were significantly lower among type III megaureters, which had the lowest rate of resolution.

Conclusions

The fate of severe megaureter seems strongly influenced by congenital renal damage secondary to a developmental abnormality of the ureteric bud. A poor resolution rate has to be expected in these cases; surgery must be reserved for symptomatic cases but has no influence on pre-existing renal damage.

Section snippets

Material and Methods

A retrospective analysis performed using medical records of 54 asymptomatic patients referred within the first month life, between 1991 and 2006, on the basis of a prenatally diagnosed megaureter (distal ureter ≥10 mm). Vesicoureteral reflux, bladder outlet obstruction, and urinary tract duplication were excluded in all cases. The male/female ratio was 47:7. Ureteral dilatation was bilateral in 15 cases. A repeated sequential dynamic US study (before and after voiding) and 99m

Results

Dilatation resolved spontaneously in 46 of 50 megaureters (92%). Thus only 4 of 37 patients (10.8%) required surgery. Among resolved cases, mean megaureter type (range, 1 to 3) at diagnosis was 1.7, and mean hydronephrosis grade (range, 1 to 5) was 1.9. Average ureteral diameter was 10.9 mm, and mean AP pelvic diameter was 11.9 mm. Mean renographic separate function was 48.8%. Average time to resolution was 24 months (range, 1 to 82 months) and was independent from sex, side, and bilaterality.

Comment

The etiology of congenital megaureter has been widely investigated. Cussen¹⁰ studied the morphology of congenitally dilated ureters and noted muscle hypertrophy and hyperplasia in obstructed megaureters (both primary and secondary types). These changes were absent or minimal in refluxing megaureters and ureters of prune-belly syndrome. Congenital ureteral muscle abnormalities may be quantitative, qualitative, or both. Many wide ureters contain adequate muscle cells and are capable of

References (17)

H.Y.A. Liu et al.
Clinical outcome and management of prenatally diagnoses primary megaureters
J Urol
(1994)
L.S. Baskin et al.
Primary dilated megaureter: long term follow up
J Urol
(1994)
A. Onen et al.
Long term follow up of prenatally detected severe bilateral newborn hydronephrosis initially managed non operatively
J Urol
(2002)
R.C. Pfister et al.
Primary megaureter in children and adultsClinical and pathophysiologic features of 150 ureters
Urology
(1978)
D.L. McLellan et al.
Rate and predictors of spontaneous resolution of prenatally diagnosed primary nonrefluxing megaureter
J Urol
(2002)
I. Ichikawa et al.
Paradigm shift From classic anatomic theories to contemporary cell biological views of CAKUT
Kidney Int
(2002)
S. Tokunaka et al.
Muscle dysplasia in ureters
J Urol
(1984)
M.K. Hanna et al.
Ureteral structure and ultrastructure, part IVCongenitally dilated ureter: Clinicopathological correlation
J Urol
(1977)

There are more references available in the full text version of this article.

Cited by (26)

Non-refluxing Primary Megaureter in Children Resolves From Proximal to Distal
2023, Urology
To evaluate a population of children with non-refluxing primary megaureter (NRPM), we investigated spontaneous resolution of ureteral dilation and the pattern (proximal to distal or distal to proximal) in which it occurs.
From our prospectively collected prenatal hydronephrosis (HN) database (0-24 months, 2008-2017), selecting those with NRPM (n = 92). We excluded patients who underwent surgery (n = 20), children with <6 months follow-up (n = 2) and without a voiding cystourethrogram (VCUG) (n = 4). Images were segregated into 198 ureteric segments (proximal/mid/distal). We defined resolution as Society for Fetal Urology (SFU) (0/1), anteroposterior diameter (APD) <10 mm, and ureteric dilatation <5 mm. Descriptive statistics and Kaplan-Meier curves were created for time-to-resolution analyses.
Of 66 patients and 198 ureteral segments, median age at presentation was 2 months (0-12), 83% were male (33% circumcised). Mean APD at baseline was 11 ± 4 mm, and 79% had (SFU 3/4) HN. Mean dilatation of ureteral segments (mm) at baseline was: 9 ± 2 proximal, 9 ± 2 mid, and 11 ± 3 distal. At a median follow-up time of 26 (7-83) months, dilation of 55 (83%) proximal, 48 (72%) mid, and 22 (33%) distal ureteric segments had resolved. Overall, HN resolution occurred in 76% of patients. Resolution rates were similar for proximal/mid-ureters (83% vs 72%; P = .20); however, they were significantly different from distal segments (83% proximal vs 33% distal; 72% mid vs 33% distal, P <.01).
Our data suggest that spontaneous resolution of NRPM follows a proximal to distal progression. Distal ureteric dilatation takes up to 10 months longer to resolve compared to that of proximal and mid-ureteric segments, as well as that of the renal pelvis.
Use of Temporary Double-J Stent Placement for Children With Congenital Hydronephrosis: A Long-Term Single-Center Cohort Study
2023, Urology
To evaluate the utilization of double-J stents in children with congenital hydronephrosis in order to avoid or postpone more invasive surgical intervention. Numerous studies have demonstrated that congenital hydronephrosis caused by ureteropelvic junction obstruction (UPJO) or primary obstructive megaureter (POM) may require a surgical correction in up to 20% of cases.
All infants with severe hydronephrosis and/or an obstructive pattern on renal scintigraphy that received double-J stent placement between 2010 to 2015 in our center were analyzed. Children were followed regularly with ultrasound and received antibiotic metaphylaxis. Urinary tract infection (UTI) and double-J dislocation were defined as complications. Treatment success was defined as avoidance of surgery and reduction of hydronephrosis to grade 1 or 0 during the observation period.
29 children were included, in these, 34 (23 UPJO, 7 POM, 4 UPJO and POM) treatment attempts were performed. Stent implantation failed in six cases, resulting in 28 double-J stent treatments, of which 19 (69%) were successful within the follow-up period of 20 to 104 months. The most common complications were febrile UTI in 6 of29 cases and double-J dislocation in 3 of 29 cases.
During the observation period, the success rate of temporary double-J in urodynamically relevant obstruction was relatively high. However, urinary tract infections and a complex disease course due to renal stent dislocation, as well as the need for repeated anesthesia and radiation exposure, should be taken into account. Hence, we do not recommend double-J stents placement in all children with congenital hydronephrosis; it may be useful in selected cases.
Acute renal failure in a neonate due to bilateral primary obstructive megaureters
2018, Journal of Pediatric Surgery Case Reports
Citation Excerpt :
Primary nonrefluxing megaureter comprises 5%–10% of all cases of prenatal hydronephrosis, and is more common in males [1,2]. It is reported that 80–90% of primary obstructive megaureter (POM) resolves spontaneously, and cases of acute renal failure are very rare [3–7]. In cases with post-obstructive renal dysfunction, the primary surgical options include endoscopic stenting, a staged reconstructive approach with temporary diversion, such as a loop cutaneous ureterostomy [8].
A male newborn was referred to our institute for postrenal acute renal failure with bilateral hydroureteronephrosis, electrolyte imbalance, and anuria. Voiding cystourethrography revealed no vesicoureteral reflux or posterior urethral valves. We performed bilateral percutaneous nephrostomy on the 9th post-natal day. The serum creatinine level improved to the normal range. Antegrade pyelography revealed bilateral uretero-vesical junction stenosis. Subsequently, we inserted bilateral double J urethral stents at 1 month. Bilateral ureteroneocystostomy without ureteral folding was performed at 6 months. The postoperative course was uneventful. This is the second case of postrenal acute renal failure with bilateral primary obstructive megaureters in a neonate.
Parenchyma-to-hydronephrosis Area Ratio Is a Promising Outcome Measure to Quantify Upper Tract Changes in Infants With High-grade Prenatal Hydronephrosis
2017, Urology
To explore the value of renal parenchyma-to-hydronephrosis area ratio (PHAR) in detecting trends of hydronephrosis (HN) improvement or worsening and response to surgical intervention.
Initial and follow-up sagittal renal ultrasound images of patients entered into a prenatal HN database from 2008 to 2016, with baseline Society for Fetal Urology (SFU) grades III and IV HN and without vesicoureteral reflux, were evaluated using National Institutes of Health-sponsored image-processing software. Renal parenchymal area, hydronephrosis area (HA), PHAR, anteroposterior diameter (APd), and SFU grade were captured at baseline and most recent visit. Data were analyzed based on the need for surgical intervention to address obstruction.
Out of 193 infants (159 boys; 135 left side), 58 (30%) underwent surgery. Patients managed surgically compared with those managed nonsurgically had worse baseline HN severity markers: SFU grade (3.6 ± 0.5 vs 3.1 ± 0.4; P < .001), urinary tract dilation classification (2.7 ± 0.5 vs 2.2 ± 0.4; P < .001), APd (20.3 ± 10.1 vs 12.8 ± 8.0; P < .001), HA (10.0 ± 6.6 vs 4.7 ± 2.8; P < .001), and PHAR (1.3 ± 1.0 vs 3.0 ± 2.9; P < .001); but both patient groups had similar renal parenchymal area (9.4 ± 3.5 vs 9.7 ± 2.8; P = .5). At last follow-up, the following discrepancies persisted: SFU grade (2.3 ± 1.0 vs 1.7 ± 1.0; P < .001), urinary tract dilation classification (1.5 ± 0.7 vs 1.0 ± 0.7; P < .001), APd (11.7 ± 8.0 vs 7.7 ± 5.7; P < .001), and HA (6.4 ± 5.1 vs 3.6 ± 2.7; P < .001); however, PHAR was equalized for both groups (7.2 ± 14.0 vs 7.1 ± 6.1; P = .9).
By concurrently considering changes in renal parenchyma and degree of HN, we found that PHAR appears to be a promising parameter that reflects similarities between patients managed surgically and those managed nonsurgically, despite initial discrepancies. Our data suggest that this variable may provide reassurance and a more objective assessment of improvement after surgery compared with other traditional ultrasound outcome measures.
Renal Parenchyma to Hydronephrosis Area Ratio (PHAR) as a Predictor of Future Surgical Intervention for Infants With High-grade Prenatal Hydronephrosis
2017, Urology
To explore the potential value of an objective assessment, renal parenchyma to hydronephrosis area ratio (PHAR), as an early predictor of surgery.
Initial sagittal renal ultrasound (US) images of patients prospectively entered into a prenatal hydronephrosis database from January 2008 to January 2016 with baseline Society for Fetal Urology (SFU) grades III and IV prenatal hydronephrosis, without vesicoureteral reflux, were evaluated using the National Institutes of Health-sponsored image processing software. PHAR, anteroposterior diameter, SFU grade, and urinary tract dilation risk categories were contrasted with nuclear scan data (differential renal function and drainage time [t_1/2]) and analyzed for predictive value in determining the decision to proceed with surgery by drawing receiver operating characteristic curves.
Out of 196 infants (162 male; 138 left sided hydronephrosis), 58 (30%) underwent surgery to address obstruction. Surgical patients compared with those managed conservatively had longer t_1/2 (60 vs 18 min; P < .01) and lower differential renal function (46 vs 50%; P = .01). Of the initial US parameters, PHAR (area under the curve = 0.816; P < .001) had a better predictive performance than anteroposterior diameter, SFU grade, or urinary tract dilation classification. PHAR values correlated with subsequent parameters obtained on nuclear scan.
PHAR is a promising parameter that can be estimated on presentation US to help predict future need for surgery in newborns with high-grade hydronephrosis.
Therapeutic mega-ureter primitive before one year of life, retrospective study of 20 years
2017, Progres en Urologie
Quelle prise en charge pour les méga-uretères primitifs chez les enfants de moins de un an ? La question est discutée dans la littérature et la controverse persiste.
Évaluer les risques et les résultats à long terme des prises en charges médicale et chirurgicale chez les enfants de moins de un an.
Étude rétrospective monocentrique de 1990 à 2010. Tous les enfants de moins de un an retrouvés ont eu une évaluation incluant un examen clinique, une échographie, une scintigraphie et une cystographie. Ils ont été répartis en deux groupes : groupe 1 : enfants opérés avant l’âge de un an, groupe 2 : enfants non opérés ou opérés après l’âge de un an. Nous avons analysé l’évolution à long terme de ces enfants sur les critères suivants : reflux, pyélonéphrites, évolution de la dilatation, fonction rénale, nécessité d’une reprise chirurgicale ou d’une chirurgie secondaire, et impact sur la fonction vésicale.
Soit 54 patients dans le groupe 1 et 56 dans le groupe 2. Pour un suivi médian de 12 ans. Un total de 101 garçons pour 9 filles (sex-ratio 11,22). Il y avait 57 MUP gauche (52 %), 22 droit (20 %) et 31 bilatéraux (28 %). Un total de 71 % de diagnostic anténatal. Pas de différence sur l’émergence de complications : 25 (groupe 1) versus 31 (groupe 2) OR = 0,69 ; IC 95 % (0,307 ; 1,574) ; p = 0,44. Pas de différence entre chirurgie secondaire et reprise chirurgicale : groupe 1 = 12, groupe 2 = 22, OR = 0,45 ; IC 95 % (0,17 ; 1,09) ; p = 0,06. Pas de différence pour l’incontinence diurne : OR = 1,04 ; IC 95 % (0,14 ; 7,64) ; p = 0,67. Soixante-seize enfants (69 %) avaient finalement été opérés, 12 enfants opérés deux fois (10,9 %) et 34 enfants (31 %) jamais opérés.
Le principal enjeu de la prise en charge des MUP est la préservation de la fonction rénale. Soixante-neuf pour cent de nos enfants ont bénéficié d’un traitement chirurgical à cause d’une altération de la fonction rénale inférieure à 30 %, d’une dilatation urétérale supérieure à 10 mm associée à un reflux ou de pyélonéphrites récidivantes. Un suivi clinique, échographique et isotopique régulier de dépistage est nécessaire et devrait être prolongé jusqu’à l’âge adulte.
5.
What is the proper way to manage complicated primary mega-ureter in infants under the age of one. This has already been discussed in the literature but the controversy remains.
Evaluate the long-term results of the management of mega-ureter based support under the age of one.
Single-center retrospective study from 1990 to 2010. All children under one year found were evaluated including clinical examination, ultrasound, scintigraphy and cystography. They were divided into two groups: group 1: children operated on before the age of one year, group 2 non-operated or operated children after the age of one year. We analyzed the long-term evolution of these children on the following criteria: reflux, pyelonephritis, changes in dilation, renal function, need for surgical revision or secondary surgery, and impact on bladder function.
In total, 54 patients were included in group 1 and 56 patients in group 2. In a median follow-up of 12 years. A total of 101 boys and 9 girls (sex-ratio 11.22). There were 57 left MUP (52%), 22 right (20%) and 31 bilateral (28%). A total of 71% of antenatal diagnosis. No difference on the emergence of complications: 25 (group 1) versus 31 (group 2) OR = 0.69; 95% (0.307; 1.574); P = 0.44. No difference between secondary surgery and revision surgery: group 1 = 12, group 2 = 22, OR = 0.45; 95% CI (0.17, 1.09); P = 0.06. No difference for daytime incontinence: OR = 1.04; 95% CI (0.14; 7.64); P = 0.67. Seventy-six children (69%) were finally made, 12 children operated twice (10.9%) and 34 children (31%) never made.
The main challenge of the MUP of management is the preservation of renal function. Sixty-nine percent of our children received surgery due to impaired renal function lower than 30% of urethral dilatation greater than 10 mm associated with reflux or recurrent pyelonephritis. Clinical monitoring, regular ultrasound and isotopic testing are necessary and should be extended to adulthood.
5.

View all citing articles on Scopus

View full text

Pediatric UrologyThe Fate of Prenatally Diagnosed Primary Nonrefluxing Megaureter: Do We Have Reliable Predictors for Spontaneous Resolution?

Objectives

Methods

Results

Conclusions

Section snippets

Material and Methods

Results

Comment

J Urol

J Urol

J Urol

Urology

J Urol

Kidney Int

J Urol

J Urol

Pediatric Urology
The Fate of Prenatally Diagnosed Primary Nonrefluxing Megaureter: Do We Have Reliable Predictors for Spontaneous Resolution?