Long-Term Followup of Primary Nonrefluxing Megaureter

Endoscopic balloon dilatation of primary obstructive megaureter: An effective first line management in children

AIM

This study evaluates outcomes of endoscopic balloon dilatation (EBD) in the management of primary obstructive megaureter (POM) in children.

METHODS

Retrospective data between 2013 and 2023 from two tertiary paediatric surgical centres in the UK were reviewed. Pre and post-operative clinical and imaging parameters of children managed with EBD were assessed. Failure of procedure was defined as requiring further intervention due to persistent/recurrent symptoms, upper tract dilatation and/or obstruction on MAG3 over the follow up period.

RESULTS

55 children with 61 renal units were evaluated. Median age at treatment was 18 months with a median follow up of 24 months. There was significant reduction in upper tract ultrasound measurements following balloon dilatation but there was no significant difference between the pre and post-operative renal function on MAG3. No significance difference was demonstrated when the outcomes of cutting and non-cutting balloons were compared. No significant difference was shown when outcomes after EBD were compared between infants vs older children as well as ureteric dilatation less than or over 25 mm (p = 0.841). 87% were successfully treated with a single dilatation and this increased to 95% after second dilatation. The remaining 5% had ureteric re-implantation.

DISCUSSION

Although a retrospective study, the patient population is relatively large. 87% success rate shown after EBD is comparable to similar studies. It has been suggested that children less than 12months and those with severe ureteric dilatation (>25 mm) may not be suitable for EBD. No significant difference was demonstrated when the outcomes of these categories of children were compared to other children with POM. All of the patients that had repeat balloon dilatation required no further intervention, a finding that has so far not been well evaluated in available literature.

CONCLUSIONS

This study demonstrates 87% success rate after single EBD in children with POM and this outcome increased to 95% following a second dilatation. EBD is shown to be an effective definitive surgical management option of POM. It can be safely offered as first line management in all patient groups and repeated if no initial response.

Advancements in Surgical Management of Megaureters

PURPOSE OF REVIEW

To review and describe the recent evolution of surgery for the various types of pediatric megaureter.

RECENT FINDINGS

Megaureter management first relies on determining the underlying cause, whether by obstruction, reflux, or a combination, and then setting appropriate surgical indications because many cases do not require surgery as shown by observation studies. Endoscopic balloon dilation has been on the rise as a major treatment option for obstructive megaureter, while refluxing megaureters can also be treated by laparoscopic and robotic techniques, whether extravesically or transvesicoscopically. During ureteral reimplantation, tapering is sometimes necessary to address the enlarged ureter, but there are also considerations for not tapering or for tapering alternatives. Endoscopic and minimally invasive surgeries for megaureter have been the predominant focus of recent megaureter literature. These techniques still need collaborative prospective studies to better define which surgeries are best for patients needing megaureter interventions.

Primary non-refluxing megaureter: Natural history, follow-up and treatment

Primary non-refluxing megaureter (PMU) is a congenital dilation of the ureter which is not related to vesicoureteral reflux, duplicated collecting systems, ureterocele, ectopic ureter, or posterior urethral valves and accounts for 5 to 10% of all prenatal hydronephrosis (HN) cases. The etiology is a dysfunction or stenosis of the distal ureter. Most often PMU remains asymptomatic with spontaneous resolution allowing for non-operative management. Nevertheless, in selective cases such as the development of febrile urinary tract infections, worsening of the ureteral dilatation, or reduction in relative renal function, surgery should be considered.

CONCLUSION

Ureteral replantation with excision of the dysfunctional ureteral segment and often ureteral tapering is the gold-standard procedure for PMU, although endoscopic treatment has been shown to have a fair success rate in many studies. In this review, we discuss the natural history, follow-up, and treatment of PMU.

WHAT IS KNOWN

• PMU is the result of an atonic or stenotic segment of the distal ureter, resulting in congenital dilation of the ureter, and is frequently diagnosed on routine antenatal ultrasound.

WHAT IS NEW

• Most often, PMU remains asymptomatic and clinically stable, allowing for non-operative management. • Nevertheless, since symptoms can appear even after years of observation, long-term ultrasound follow-up is recommended, even up to young adulthood, if hydroureteronephrosis persists. • Ureteral replantation is the gold standard in case surgery is needed. In selected cases, however, HPBD could be a reasonable alternative.

Endoscopic treatment of primary obstructive megaureter with high pressure balloon dilation in infants

INTRODUCTION AND OBJECTIVE

Ureteral reimplantation of the dilated ureter in infants is challenging; however, some patients with primary obstructive megaureter (POM) in this age group require intervention due to clinical or radiological progression. We sought to determine if high pressure balloon dilation (HPBD) can serve as a definitive treatment for POM in children under one year of age, or as a temporizing measure until later reimplantation.

MATERIALS AND METHODS

All patients from a single institution who underwent HPBD between October 2009 and May 2022 were retrospectively reviewed. Patients were excluded if older than 12 months or diagnosed with neurogenic bladder, posterior urethral valves, or obstructed refluxing megaureter. Patients with prior surgical intervention at the ureterovesical junction were excluded. Indications for surgery included progressive hydroureteronephrosis or urinary tract infection (UTI). Balloon dilation was performed via cystoscopy with fluoroscopic guidance, followed by placement of two temporary ureteral stents. Primary outcomes were improvement or resolution of megaureter and rates of subsequent reimplantation. Secondary outcomes included total number of anesthetics and postoperative UTIs.

RESULTS

Fifteen infants with median age of 7.6 months (IQR 3.8-9.7) underwent HPBD. Twelve (80%) patients were detected prenatally and 3 (20%) after a UTI. Indication for surgery was progressive hydroureteronephrosis in 10 patients (67%) and UTI in five (33%). All had SFU grade 3 or 4 hydronephrosis on preoperative ultrasound and median distal ureteral diameter was 13 mm. Median follow up was 2.9 years. Twelve (80%) succeeded with endoscopic treatment: 7 patients had an undetectable distal ureter on ultrasound at last follow-up, 5 were improved with median distal ureteral diameter of 7 mm. Three patients (20%) required ureteral reimplantation due to progressive dilation, all with grade 4 hydronephrosis and distal ureteral diameters were 11, 15, and 21 mm. Six patients (40%) required two anesthetics to complete endoscopic treatment. Among those, 4 patients required initial stent placement for passive dilation followed by a second anesthetic for HPBD weeks later. Two patients underwent repeat HPBD following postoperative proximal migration of the ureteral stents. All 15 patients had an additional anesthetic for removal of stents. Five patients (33%) were treated for a symptomatic UTI (4 febrile, 1 afebrile) with the stents indwelling but there were no UTIs in the group following stent removal.

CONCLUSION

Balloon dilation is a practical option for treatment of POM in infants, and in most cases (80%) avoids subsequent open surgery (over median 2.9 years of follow-up).

Spontaneous resolution and the role of endoscopic surgery in the treatment of primary obstructive megaureter: a review of the literature

The megaureter accounts for almost a quarter of all urinary tract dilations diagnosed in utero and is the second leading cause of hydronephrosis in newborns, following pyeloureteral junction obstruction. The current standard treatment for progressive or persistent, symptomatic primary obstructive megaureter is ureteral anti-reflux reimplantation, which can be associated with ureteral remodeling or plication. Due to the associated morbidity, postoperative recovery challenges, and the complications that may arise from the open surgical approach, there has been a natural inclination towards validating new minimally invasive techniques. This study reviews the literature, extracting data from three major international databases, from 1998 to 2022. Out of 1172 initially identified articles, only 52 were deemed eligible, analyzing 1764 patients and 1981 renal units. Results show that 65% of cases required surgical intervention, with minimally invasive techniques constituting 56% of these procedures. High-pressure endoscopic balloon dilation was the preferred endourologic technique. The degree of ureterohydronephrosis is considered one of the factors indicating the need for surgery. There is an inverse relationship between the diameter of the ureter and the likelihood of spontaneous resolution. Conditions such as renal hypoplasia, renal dysplasia, or ectopic ureteral insertion strongly indicate a poor prognosis. Endoscopic surgical techniques for treating primary obstructive megaureter can be definitive, firstline treatment options. In selected cases, they might be at least as effective and safe as the open approach, but with advantages like quicker recovery, fewer complications, shorter hospital stays, and reduced costs.

Non-refluxing Primary Megaureter in Children Resolves From Proximal to Distal

OBJECTIVES

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Non-surgical management in children with non-refluxing primary megaureter: a systematic review and meta-analysis

BACKGROUND

Children with non-refluxing primary megaureter are mostly managed by a watchful approach with close follow-up and serial imaging.

OBJECTIVES

This systematic review and meta-analysis aimed to determine whether there is sufficient evidence to support the current non-surgical management strategy in these patients.

DATA SOURCES

A comprehensive search including electronic literature databases, clinical trial registries, and conference proceedings was performed.

DATA SYNTHESIS METHODS

Outcomes were estimated as pooled prevalence. If meta-analytical calculations were not appropriate, outcomes were provided in a descriptive manner.

RESULTS

Data from 8 studies (290 patients/354 renal units) were included. For the primary outcome, differential renal function estimated by functional imaging, meta-analysis was impossible due to reported data not being precise. Pooled prevalence for secondary surgery was 13% (95% confidence interval: 8-19%) and for resolution 61% (95% confidence interval: 42-78%). The risk of bias was moderate or high in most studies.

LIMITATIONS

This analysis was limited by the low number of eligible studies with few participants and high clinical heterogeneity, and the poor quality of the available data.

CONCLUSIONS

The low pooled prevalence of secondary surgical intervention and high pooled prevalence of resolution may support the current non-surgical management in children with non-refluxing primary megaureter. However, these results should be interpreted cautiously due to the limited available body of evidence. Future studies should overcome existing limitations of imaging methods by using standardized, comparable criteria and report outcome parameters in a quantitative manner. This would allow more sufficient data synthesis to provide evidence-based recommendations for clinical decision-making and counseling.

SYSTEMATIC REVIEW REGISTRATION

The protocol was registered on PROSPERO under CRD42019134502.

Endoscopic balloon dilation of primary obstructive megaureter: is fluoroscopic guidance necessary?

OBJECTIVE

To compare the long-term effectiveness, complications, and outcomes of primary obstructive megaureter (POM) treated by endoscopic balloon dilation under fluoroscopic guidance versus not using radioscopy during the procedure.

PATIENTS AND METHODS

A comparative study between POM cases treated at our institution by endoscopic balloon dilation (EBD) under fluoroscopic guidance (FG) (n = 43) vs no fluoroscopic guidance (NFG) (n = 48) between the years 2004 and 2018 was conducted. The procedure in FG consisted of performing a retrograde pyelography before dilation. Then, a guidewire is introduced to the renal pelvis, and the dilation of the vesicoureteral junction is performed using high-pressure balloon catheters under fluoroscopic vision. Finally, a double-J stent is placed between the renal pelvis and bladder. The procedure in NFG was performed exclusively under cystoscopic vision without radiological exposure. Complications, outcomes, and success rates were analyzed using Spearman's correlation test. Mean follow-up was 12.5 ± 2.2 years in FG and 6.4 ± 1.3 years in NFG.

RESULTS

MAG-3 showed significant differences in renal drainage before and after endoscopic treatment in both groups (p < 0.001 T-test). Statistical analysis did not reveal differences between groups in initial technical failure (r: - 0.035, p = 0.74), early postoperative complications (r: - 0.029, p = 0.79), secondary VUR (r: 0.033, p = 0.76), re-stenosis (r: 0.022, p = 0.84), long-term ureteral reimplantation (r: 0.065, p = 0.55), and final outcome (r: - 0.054, p = 0.61). The endoscopic approach of POM had a long-term success rate of 86.5% in FG VS 89.6% in NFG.

CONCLUSIONS

Endoscopic balloon dilation of POM can be done with no radiation exposure with similar results, effectiveness, and outcomes.

Ureteral dilation recovery after intravesical reimplantation in children with primary obstructive megaureter

Background

To observe the postoperative recovery following ureteral dilation in primary obstructive megaureter (POM) after ureteral implantation, and evaluate the risk factors affecting ureter diameter resolution.

Materials and Methods

A retrospective study was performed in patients with POM who underwent ureteral reimplantation using the Cohen procedure. Patient characteristics, perioperative parameters, and postoperative outcomes were also analysed. A widest ureteral diameter of <7 mm was defined as a normal shape and outcome. Survival time was defined as the time from surgery to ureteral dilation recovery or to the last follow-up.

Results

A total of 49 patients (54 ureters) were included in the analysis. The survival time ranged from 1 to 53 months. The shapes of a total of 47 (87.04%) megaureters recovered, and most (29/47) resolutions happened within 6 months after surgery. In the univariate analysis, bilateral ureterovesical reimplantation (p = 0.015), ureteral terminal tapering (p = 0.019), weight (p = 0.036), and age (p = 0.015) were associated with the recovery time of ureteral dilation. A delayed recovery of ureteral diameter was noted in bilateral reimplantation (HR = 0.336, p = 0.017) using multivariate Cox regression.

Conclusions

Ureteral dilation in POM mostly returned to normal within six postoperative months. Moreover, bilateral ureterovesical reimplantation is a risk factor for delayed postoperative recovery of ureter dilation in POM.

Postoperative JJ stent is not necessary after balloon high-pressure endoscopic dilatation of primary obstructive megaureter

INTRODUCTION

A wide range of surgical interventions have been described for the management of primary obstructive megaureter (POM). Endoscopic balloon dilatation has been developed through last decades as a minimally invasive alternative to classic surgery.

OBJECTIVE

To assess the need for placement of a double J stent after endoscopic balloon dilatation procedure, by comparing the post-operative related outcomes with and without double J placement. Secondary outcome was the success rate, considering the need for further procedure after endoscopic balloon dilatation and the improvement of the ureteral diameter in the two groups.

STUDY DESIGN

Historical retrospective comparison of children treated by endoscopic dilatation for POM, with post-operative JJ stent left in place (2012-2014) or without ureteral JJ stent (since 2015). Post-operative complications were reported following Clavien-Dindo grading system and compared between the two groups. Success rate was defined as absence of need for further surgical reimplantation. Ureteral diameters on preoperative and postoperative renal ultrasounds were compared.

RESULTS

Endoscopic dilatations were performed in 42 patients for 46 renal units during the study period. There was a significantly higher rate of post-operative complications in the group with JJ stenting compared to the group without double J stenting regarding all Clavien-Dindo grades (56% vs 15%, p = 0.014) and Clavien-Dindo grade III only (31% vs 0%, p = 0,0051) (Figure). The success rate was similar in the JJ group (75%, F-up: 70 months [13-101]) and the no JJ group (81%, F-up: 26 months [12-95]). There was a significant improvement of US renal pelvis and ureter dilatation in both groups, with a median follow-up of 35.5 months [12-101].

DISCUSSION

The overall rate of complications was slightly higher than in other reports and higher in the JJ group regarding Clavien-Dindo grade III complications. The success rate was comparable to previous studies reviewing endoscopic dilatations and equivalent in the two groups.

CONCLUSION

In our study, the omission of postoperative ureteral drainage by a JJ stent after endoscopic balloon dilatation of POM did not increase post-operative complications rate without demonstrable impact on the success rate.

Transvesicoscopic ureteral reimplantation and ureteroscopy for management of primary obstructed non‐refluxing megaureter with ureteral calculus

Introduction

Primary obstructed non‐refluxing megaureter, a type of congenitally dilated ureter, often resolves spontaneously. Surgery may be indicated in symptomatic cases; however, there are no reports of transvesicoscopic ureteral implantation and ureteroscopy for ureteral stones. Therefore, we describe the treatment of primary obstructed non‐refluxing megaureter and ureteral calculi using this technique.

Case presentation

A 6‐year‐old Japanese girl was referred for abdominal pain and gross hematuria due to right megaureter with multiple stones in the renal lower‐pole calyces and ureter. She was diagnosed with primary obstructed non‐refluxing megaureter and ureterovesical junction obstruction. The stones were removed using mini‐percutaneous nephrolithotomy and transvesicoureteroscopic surgery, respectively. A narrow segment of the right ureter was cut, and transvesicoscopic ureteral plication and reimplantation were performed. The procedures were successful without postoperative complications.

Conclusion

Transvesicoscopic ureteral reimplantation with ureteroscopy may be a safe, effective and minimally invasive surgical option for ureterovesical junction obstruction with ureteral stones.

Telocytes, c-Kit positive cells, Smooth muscles, and collagen in the ureter of pediatric patients with congenital primary obstructive megaureter: elucidation of etiopathology

Congenital primary obstructive megaureter (POM) is an uncommon pediatric anomaly that is due to obstructive distal ureter leading to the loss of peristalsis with consequent ureterohydronephrosis causing loss of kidney function. The objectives are to elucidate the etiology of POM by demonstrating the presence of interstitial cells of Cajal (ICC), telocytes, smooth muscles, and collage in the obstructive and dilated ureteral segments. The study was carried out on 15 surgical specimens of congenital POM in pediatric patients, age range was 4 to 24 months, they were operated upon by excision of the obstructed segment, tailoring the dilated ureter, and anastomosing it to the bladder. Specimens included the obstructed ureteral segment and part of the dilated ureter. Specimens were examined with hematoxylin and eosin (H&E) stain, Modified Gomori trichrome stain, immunohistochemistry (IHC) with α-muscle actin, and c-kit (CD117), and transmission electron microscopy (TEM). Obstructed segment showed excess collagen intervening between smooth muscles, excess c-Kit positive cells, and presence of telocytes. The dilated segment of the ureteral wall is formed of smooth muscle bundles with scanty collagen. Staining with c-Kit did not demonstrate positive cells. TEM showed myofibroblasts and close adherence of smooth muscle cells to each other with absence of telocytes. The pathophysiology of POM is multifactorial. Loss of interstitial cells and rarity of collagen result in loss of elasticity of dilated segment leading to massive dilatation. While the obstructed segment had no muscle conductivity due to excess collagen irrespective of presence of telocytes.

Does Renal Function Remain Stable after Puberty in Children who underwent Ureteral Reimplantation due to Ureterovesical Junction Obstruction?

INTRODUCTION

 Ureteric reimplantation due to ureterovesical junction (UVJ) obstruction enjoys high success in the short term. However, renal function after reimplantation must accommodate the numerous changes in the pediatric urinary tract that occur along with child development that may theoretically cause an occult loss of renal function. The purpose of this study was to evaluate whether improved renal function after ureter reimplantation for antenatal diagnosed UVJ obstruction remains stable after puberty.

MATERIALS AND METHODS

 Twenty-one children who underwent open reimplantation using Politano-Leadbetter technique were followed until they completed puberty. Mean age at surgery was 14.3 months (range: 3-60 months). Five (23.8%) of 21 children had right hydronephrosis, 13 (61.9%) had left hydronephrosis, and 3 (14.3%) had bilateral hydronephrosis. The Society for Fetal Urology (SFU) level of the hydronephrosis was 3 (47.6%) in 10 children and 4 (52.4%) in remaining 11. Fourteen (66.6%) patients had poor renal function upon surgery and the remaining seven (33.4%) patients had moderate renal function. The mean renal function upon operation was 28 ± 4.3 (mean ± standard deviation [SD]).

RESULTS

 Reimplantation led to the increase in the RRF in the short-term period from 28 ± 4.3% prior to the surgery to 36.4 ± 5% (p < 0.001) in all patients and remains stable 35 ± 5% after puberty in all the reviewed patients.

CONCLUSION

 Our data demonstrate for the first time that successful ureteral reimplantation following antenatal diagnosis of UVJ obstruction is associated with an improvement in renal function, not only during short- and midterm follow-up but also allows preserving the renal function throughout the puberty period.

Side predilection in congenital anomalies of the kidney, urinary and genital tracts

BACKGROUND

There appear to be various patterns of sidedness with relation to the common urogenital malformations observed in pediatric urology. The objective of this statistical review was to synthesize this data and to assess if these patterns are significant.

MATERIALS AND METHODS

Eighteen urogenital conditions were investigated and for each condition the five largest studies that noted laterality were included. The sidedness of each condition was then analysed for statistical significance.

RESULTS

Three conditions had a statistically significant higher proportion on the right side: palpable undescended testis (63%, p = 0.0002), inguinal hernia (59%, p = 0.0001) and hydrocele (60%, p = 0.003). Three conditions were significantly more common on the left side: impalpable undescended testis (59%, p = 0.0008), renal agenesis (54%, p = 0.02) and vesico-ureteric junction obstruction (71%, p < 0.0001) while both pelvi-ureteric junction obstruction (62%, p = 0.09) and absent vas deferens (61%, p = 0.11) were trending towards significance.

CONCLUSIONS

Various urogenital malformations display a predilection for one side. Proximal malformations tend to be more frequently seen on the left side, where as inguinoscrotal malformations are more frequently observed on the right. There is an increasing body of literature regarding aetiological factors for these conditions. However, our current understanding of the pathophysiology of these conditions does not completely explain this pattern of observation.

Comparative Clinical Study Between Modified Ureteral Orthotopic Reimplantation and Cohen Method Under Pneumovesicum in Pediatric Patients With Hydroureteronephrosis

Purpose: To report our initial experience with a modified ureteral orthotopic reimplantation technique under pneumovesicum and compare the outcomes vs. those obtained with the Cohen technique under pneumovesicum for the correction of primary obstructive megaureter (POM) or vesicoureteral reflux(VUR) in pediatric patients. Methods: A total of 46 patients (38 POM and 8 VUR; mean age: 16.24 months) treated with modified ureteral orthotopic reimplantation (OR) and 43 patients (34 POM and 9 VUR; mean age: 22.98 months) treated with Cohen reimplantation (CR) under pneumovesicum were included. We compared the results perioperatively and during follow-up. Results: The mean operative time was significantly shorter in the OR group (OR: 86.86 and 108.18 vs. CR: 95.14 and 124.29 min for unilateral and bilateral cases, respectively). The mean postoperative hospital stay (OR: 5.02 vs. CR: 5.07 days), blood loss (OR: 3.67 vs. CR: 3.84 ml), and follow-up time (OR: 23.17 vs. CR: 23.37 months) did not exhibit significant differences between the two groups. One patient converted to open surgery in the CR group, whereas there was no conversion in the OR group. Postoperative febrile urinary tract infection occurred in two cases in each group. Both infections were controlled using antibiotics. All patients in both groups showed improved hydroureteronephrosis, and all patients with VUR showed reflux resolution post-surgery. Conclusions: Our modified ureteral orthotopic reimplantation technique under pneumovesicum can be safely and effectively performed, achieving a high success rate that is equivalent to that obtained through the Cohen technique under pneumovesicum. Moreover, it involves a simpler procedure and shorter operation time.

Primary Non-refluxing Megaureter: Analysis of Risk Factors for Spontaneous Resolution and Surgical Intervention

Background: The risk of febrile urinary tract infection (fUTI) in children with primary non-refluxing megaureter (PM) has been extensively studied in the literature, however, a paucity of information exists regarding risk factors for surgical intervention and spontaneous resolution. We sought to analyze data from our prospectively collected PM cohort to determine risk factors that would predict surgery and resolution in this population. Methods: Patients with PM were identified from our prospectively-collected prenatal hydronephrosis (HN) database from 2008 to 2017. Primary outcomes included surgical intervention and hydroureter resolution. Spontaneous resolution was defined as ureteral dilation <7 mm at last follow-up. Age at presentation, gender, development of fUTI, HN grade [low (SFU I/II) vs. high (SFU III/IV)], anteroposterior diameter (APD) measurements and ureteral diameter at baseline and last follow-up were recorded. Univariate and multivariable analyses (binary logistic and Cox regression) were performed. Results: Of 101 patients, 86 (85%) were male, and 80 (79%) had high grade HN. Median age at baseline and last follow-up were 2 (0-23) and 29 (2-107) months, respectively. Overall, 23 (23%) patients underwent surgery at a median age of 22 (3-35) months. Mean ureteral diameter was larger in surgical patients vs. those treated non-surgically (14 ± 4 vs.11 ± 3 mm; p < 0.01). Of the 78 (77%) non-surgical patients, 43(55%) showed resolution of their ureteral dilation at a median age of 24(4-56) months. Survival analysis demonstrated that 12 patients resolved by year 1, 22 by year 2, 30 by year 3, 40 by year 4, and 43 by year 5. However, when considering resolution as APD <10 mm, 62(79%) children resolved their HN by last follow-up (29 months). Univariate and multivariable analyses (Table 1) revealed that high-grade HN at baseline, development of fUTI, and ureteric dilation ≥14 mm were significant risk factors for surgical intervention. Cox regression (Figure 2) found that ureteral dilation <11 mm was the only independent risk factor significantly associated with PM resolution (Table 2). Conclusion: Patients with PM and high-grade HN, as well as individuals with ureteral dilation ≥14 mm and fUTI were more likely to undergo surgical intervention. Ureteral dilation <11 mm was the only independent risk factor significantly associated with spontaneous resolution of PM.

Diuresis renography in the evaluation and management of pediatric hydronephrosis: What have we learned?

Diuresis renography (DR) is widely used in the evaluation of hydronephrosis and hydroureter in infants and children. The goal of this provocative nuclear imaging examination should be to detect the hydronephrotic kidneys at risk for loss of function and development of pain, hematuria, and urinary tract infection. The reliability of DR is dependent on the acquisition and processing of the data as well as interpretation and utilization of the results. In this review, the key concepts of standardized DR and pitfalls to avoid are highlighted.

Use of MR Urography in Pediatric Patients

PURPOSE OF REVIEW

In this article, we describe the basics of how magnetic resonance urography (MRU) is performed in the pediatric population as well as the common indications and relative performance compared to standard imaging modalities.

RECENT FINDINGS

Although MRU is still largely performed in major academic or specialty imaging centers, more and more applications in the pediatric setting have been described in the literature. MRU is a comprehensive imaging modality for evaluating multiple pediatric urologic conditions combining excellent anatomic detail with functional information previously only available via renal scintigraphy. While generally still reserved for problem solving, MRU should be considered for some conditions as an early imaging technique.

Endoscopic balloon dilatation in primary obstructive megaureter: Long-term results

BACKGROUND

Open neoureterocystostomy is the traditional surgical treatment for primary obstructive megaureter (POM). Endoscopic balloon dilation is a new minimally invasive alternative. It has been shown to be a safe and effective endoscopic procedure over short-term follow-up; however, few studies have shown its long-term efficacy.

OBJECTIVE

The aim of this study was to evaluate the long-term results and complications of balloon dilation for the treatment of primary obstructive megaureter in infants.

MATERIALS AND METHOD

A retrospective review was performed of patients with primary obstructive megaureter treated with balloon dilation. The diagnosis was made through ultrasonography, diuretic isotopic renogram, and voiding cystourethrogram (VCUG). The indications for surgery were: worsening hydronephrosis, renal function impairment, and recurrent urinary tract infections (UTI). All patients were followed 3 months after the endoscopic procedure with ultrasonography and MAG-3 renogram, and 6 months after surgery with VCUG and ultrasonography. Annual ultrasound and clinical follow-up were performed until present time.

RESULTS

Seven boys and six girls were treated (median age 9 months, range 2-24). Ten patients had a prenatal diagnosis of hydronephrosis, and the diagnoses was made after UTI in three patients. No intraoperative complications were observed. One double-J stent was replaced after endoscopic procedure for malpositioning, and four patients developed UTIs after surgery. All patients had non-obstructive MAG-3 diuretic renogram 6 months after surgery. The mean washout on the renogram and the ultrasound pelvic diameter showed pre-operative and postoperative statistical differences (Summary Table). All patients maintained their results without recurrence or any other complications in the long-term follow-up. The median follow-up was 10.3 years (range 4.7-12.2).

DISCUSION

In 2014, Aparicio et al. first described balloon dilation being used as a definitive treatment for primary obstructive megaureter in infants. Bujons et al. also presented 20 cases with a mean follow-up of 6.9 years. The current study is the largest to date, with a median follow-up of 10.2 years. It demonstrated the value of balloon dilation as a definitive treatment for POM. Despite these results, it was difficult to establish endoscopic balloon dilation as a definitive treatment for POM, due to the absence of long-term studies like the current one.

CONCLUSION

Balloon dilation can be a safe and effective endoscopic procedure for the treatment of primary obstructive megaureter in infants, and has shown good outcomes in long-term follow-up. More studies are needed to demonstrate these results.

Long-Term Outcomes in Primary Obstructive Megaureter Treated by Endoscopic Balloon Dilation. Experience After 100 Cases

Aim: To assess long-term effectiveness, complications, and outcomes of primary obstructive megaureter (POM) treated by endoscopic balloon dilation (EBD) in the largest series reported. Patients and Methods: Hundred POM in 92 consecutive patients were treated by EBD between years 2004 and 2016. A total of 79 POM (73 patients) with more than 18 months of follow-up after treatment have been analyzed. EBD of the vesicoureteral junction was performed with semicompliant high-pressure balloon catheters (2.7FG) with minimum balloon diameter of 5 mm, followed by temporary Double-J stent placement. Follow-up protocol included periodical clinical reviews, US and MAG-3 renogram scans. Results: Median age at surgery was 4 months (15 days-3.6 years), with median operating time of 20 min (10-60) and hospital stay of 1 day (1-7). Initial renal function was preserved in all patients with significant improvement in renal drainage on the MAG-3 diuretic renogram after endoscopic treatment (p < 0.001 T-test). Significant post-operative differences were observed in hydronephrosis grade and ureteral diameter that were maintained in the long-term (p < 0.001 T-test). Endoscopic approach of POM had a long-term success rate of 87.3%, with a mean follow-up of 6.4 ± 3.8 years. Secondary VUR was found in 17 cases (21.5%), being successfully treated by endoscopic subureteral injection in 13 (76.4%). Nine cases developed long-term re-stenosis (12.2%) that were successfully treated with a new EBD in 8. Endoscopic management of POM failed in 10 cases (12.7%) that required ureteral reimplantation. Five were early failures (4 intraoperative technical problems and 1 double-J stent migration with severe re-stenosis), and 5 long-term (4 persistent VUR and 1 re-stenosis recurrence). Conclusion: EBD has shown to be an effective treatment of POM with few complications and good outcomes at long-term follow up. Main complication was secondary VUR that could also be treated endoscopically with a high success rate. In our opinion, EBD may be considered first-line treatment in POM.

Modified ureteral orthotopic reimplantation method for managing infant primary obstructive megaureter: a preliminary study

PURPOSE

To describe a modified ureteral orthotopic reimplantation method in infant with primary obstructive megaureter (POM) and report our initial experience.

METHODS

Thirteen children with POM (range 1-7 months) underwent modified transvesical ureteral implantation surgery. Treatment consists of transecting the ureter proximal to the obstruction and performing orthotopic reimplantation in end freely fashion with distal ureter protruding into the bladder, providing dilated ureteral diameter: ureteral exposure length in bladder ratio of 1:1.5-2. All patients underwent repeat ultrasound, radionuclide imaging and voiding cystourethrography. Cystoscopy was conducted in patients at 6 months after surgery.

RESULTS

The mean operating time was 40 min. There were one redo this procedure for recurrent obstruction and one Cohen reimplantation for Grade 5 vesico-ureteral reflux in one bilateral POM. Hydroureteronephrosis improved in other 11 patients, and the ureter diameter was significantly reduced from preoperative measurements. At the time of cystoscopy, thick and large volcanic-shaped ureteral orifice was found and urine ejected intermittently.

CONCLUSIONS

The proposed 'modified ureteral orthotopic reimplantation' with no tapering or advancement for POM in infants is a simple, feasible and less invasive procedure that had good success rates in this small series. Further, larger studies are required to support or negate the usefulness of this technique.

Isolated low initial differential renal function in patients with primary non-refluxing megaureter should not be considered an indication for early surgery: A multicentric study

INTRODUCTION

Low initial differential renal function (DRF) in patients with primary non-refluxing megaureter (PNRM) is considered an indication for surgery as are an increase of dilatation and symptoms.

OBJECTIVE

We hypothesized that low DRF is not necessarily a result of obstruction, but may be due to impaired development of the upper urinary tract. Thus, in the absence of symptoms, there is a low risk for further loss of renal function. This study aimed to assess whether initially low DRF is a reliable indicator of obstruction.

STUDY DESIGN

We reviewed data from four university centers between 1995 and 2010. Patients under 12 months of age with unilateral primary non-refluxing megaureter (PNMR) and a DRF between 10% and 40%, and followed minimally 24 months, were included. Patients were placed in two groups based on management: group A, surgical; group B, conservative. The dynamics of DRF in relation to age and type of treatment was studied. In each patient we recorded the earliest (initial) DRF, the last known (final) DRF, the age when MAG-3 scans were performed and the type of treatment.

RESULTS

From 25 patients, 16 were treated surgically (group A) and 9 followed conservatively (group B). The initial mean DRF in group A was 33.1% and in group B 34.5%, at a mean age 3.0 and 3.6 months, respectively. The final mean DRF in group A was 40.1% and in group B 43%, at a mean age 59.9 and 46.3 months, respectively. Using two-way repeated ANOVA (age [initial DRF, final DRF] vs. group [group A, group B]), we found non-significant difference between the groups in the DRF, F (1, 21) = 0.96, p = 0.338, while we observed statistically significant and similar increase from the initial to final DRF in both groups, F (1, 21) = 16.66, p = 0.001 (Figure).

DISCUSSION

This is the first study focusing on the evolution of renal function in patients with PNRM and low initial DRF. Results suggest that the diagnosis of obstruction is inaccurate in most infants with unilateral PNRM if it is based on low initial DRF only. Renal deterioration rarely occurs in asymptomatic patients, and even profoundly impaired kidneys have potential for improvement. Limitations of our study include retrospective design and lack of standardization of treatment among the four centers.

CONCLUSION

Low DRF in asymptomatic and anatomically stable patients with PNMR should not be considered an indication for early surgery. These findings challenge current practice and should be confirmed by a prospective study.

[Pitfalls for renogram interpretation in pediatric urology]

Renograms are currently used for functional assessment by pediatric urologists. The aim of the present work was to focus on the potential pitfalls concerning renography. Potential confounding factors are described in reference to concrete cases. The main types of pitfalls concern venous or urinary catheters and background area definition. Protocols and renogram interpretation are critiqued in a bibliographic review. We propose a technical update and original data on the potential pitfalls in renography interpretation. Multidisciplinary discussion between nuclear medicine, pediatrics and pediatric surgery departments is required before drawing conclusions.

Conservative management of primary non-refluxing megaureter during the first year of life: A longitudinal observational study

INTRODUCTION

There is a lack of prospective studies that include a selected population of patients with primary non-refluxing megaureter (PM). Thus, a longitudinal observational study was designed to follow from birth a selected population of children with PM; all were antenatally diagnosed. In this paper, the outcomes observed in the first year of life are presented.

OBJECTIVE

The primary aim was to follow the natural history of PM. The secondary aim was to monitor the onset of any potential complications such as urinary tract infections (UTIs), need for hospitalization and need for surgical correction.

STUDY DESIGN

All children with antenatally diagnosed PM, born between January 2007 and December 2013, were prospectively followed with observational management: renal ultrasonography and clinical evaluation on a 3-month basis; urinalysis and culture in case of symptoms; and mercaptoacetyltriglycine (MAG3) nuclear scan once older than 1 month. Children presenting at birth with mild urinary tract dilatation were included in Group A; those with moderate-to-severe dilatation were included in Group B. Continuous antibiotic prophylaxis (CAP) was administered to Group B.

RESULTS

Forty-seven children (44 males, three females) with 58 PM were included in the study. The participants and their corresponding outcomes are shown in the summary Table. The presence of obstruction at renogram was a significant predictor of UTIs and hospitalization.

DISCUSSION

The strengths of this study were its prospective nature and its very consistent population. A limitation was the lack of control groups. The results regarding the negligible incidence of complications in Group A and the residual incidence of febrile UTIs (20%) and hospitalization (17%) in Group B, even with CAP, are in line with previous literature. In contrast, there was a higher risk of UTIs observed in children aged older than 6 months.

CONCLUSIONS

Resolution or improvement is expected in all cases of PM with mild postnatal dilatation, and close to 60% of those with moderate or severe dilatation. Surgery is rarely performed on children younger than 1 year of age. It is safe to observe children with mild urinary tract dilatation without CAP, because the incidence of UTIs is negligible. In those presenting with moderate or severe urinary tract dilatation, despite CAP, a residual incidence of UTIs is seen, and symptomatic patients often require hospitalization. However, UTIs are well tolerated and do not seem to modify outcome. Cases showing obstruction on the MAG3 scan seem to be at higher risk of UTIs and hospitalization.

Can endoscopic balloon dilation for primary obstructive megaureter be effective in a long-term follow-up?

BACKGROUND

Ureteral tapering and reimplantation is an established treatment for persistent or progressive primary obstructive megaureter (POM) but may result in complications and morbidity. Use of a less invasive technique involving endoscopic balloon dilation appears very interesting.

OBJECTIVE

The objective of this report is to determine if endoscopic balloon dilation for POM is effective in the long term as well as to assess complications of the procedure.

MATERIAL AND METHODS

A retrospective review was done on 19 patients and 20 ureters treated with the endoscopic balloon dilation by POM from June 2000 to February 2010. Surgery was performed solely in those cases in which there was persistence of obstruction in the renogram along with one or all of the following conditions: impairment of the differential renal function <40%, worsening of the renal pelvic dilation, febrile UTI in spite of antibiotic prophylaxis or renal calculi. The patients comprised 16 boys and 3 girls with a mean age at surgery of 17 months (range 1-44 months). Ten cases were left sided, eight right sided, and one bilateral. Under endoscopic and fluoroscopic guidance, a 3-5 Fr dilating balloon was inflated to 12-14 atm, or until disappearance of the stenotic obstructive area. A double J stent was positioned and withdrawn 2 months later. Follow-up recorded the presence of symptoms, number of reintervention procedures registered, and included renal ultrasound and MAG-3 renogram.

RESULTS

There were no perioperative complications. Eighteen ureters showed a non-obstructive pattern on MAG-3 renogram after the first endoscopic dilation, representing a 90% success rate. One case required a second dilation, which proved successful and two cases of recurrent lithiasis required ureterotomy without instances of obstruction. 2 patients had a febrile UTI and a vesicoureteral reflux was diagnosed in one. Renal function was preserved in 95% of patients. The mean follow-up was 6.9 years (range 3.9-13.3 years). One patient was lost after the procedure.

DISCUSSION

In an era of minimally invasive techniques, the search for less invasive procedures for treatment of POM has resulted in a variety of surgical options. Angulo et al., in 1998 and our group described the first POM treatment with endoscopic balloon dilation, which is believed to be a definitive, less invasive, and safe treatment. Furthermore, should an endoscopic approach fail, reimplant surgery can be performed. Few publications have reported short series with good results in the short and medium term. Torino et al. presented five cases in children aged less than 1 year, none of these showed evidence of obstruction. García-Aparicio et al. presented a series of 13 patients treated with a success rate of 84.6%. Christman et al. added laser incision in cases of narrowed ureteral segment 2-3 cm long and used double stenting. Good outcomes were presented in 71%. Romero et al. reported improvement of drainage within the first 18 months after treatment in 69% of patients. The potential de novo onset of vesicoureteral reflux may be the source of some controversy. We consider that dilation does not significantly alter the antireflux mechanism. In VCUG is not systematically performed because it is an invasive test. This restricts the conclusions that can be drawn from our findings. Nevertheless, some groups continue to systematically perform VCUG.

CONCLUSIONS

Endoscopic balloon dilation for POM is a safe, feasible, and less invasive procedure that shows good outcomes on long-term follow-up. However, multicenter studies and prospective trials should be encouraged to provide more definitive evidence on its benefits.