Antenatally detected pelvi-ureteric junction obstruction: concerns about conservative management

Predictive Value of the Postural Difference in Antero-Posterior Diameter of Renal Pelvis on Ultrasonography of Unilateral Ureteropelvic Junction Obstruction in Determining the Need For Surgery

BACKGROUND

Ureteropelvic junction obstruction (UPJO) is the most common cause of antenatal hydronephrosis. Although majority of them improve with time, none of the existing diagnostic modalities can accurately predict which hydronephrotic kidney is at the risk of progressive renal damage and will benefit from early surgery. Postural variations in the anteroposterior pelvic diameter (APPD) of the hydronephrotic kidney in children during follow-up postnatal ultrasonography (USG) reflect the intrapelvic tension, which might help in predicting the need of surgery amongst these patients.

MATERIALS AND METHODS

We designed this prospective observational study in all unilateral UPJO patients on postural variation in the APPD of renal pelvis on ultrasonography. The mean age of all patients were 2.15 years (0-5 years) and managed at our institute at All India Institute of Medical Sciences, Bhubaneswar. The study duration was from July 2019 to May 2021. The management of these patients was done as per the standard institutional protocol and there was no deviation due to inclusion in this study. We documented the variations in postural APPD both amongst the conservatively managed group and the surgically managed group of patients. Linear correlation between two continuous variables was explored using Pearson's correlation (if the data were normally distributed) and Spearman's correlation (for non-normally distributed data).

RESULTS

We found a higher prone APPD than supine APPD in all these patients indicating the obstruction at ureteropelvic junction. However, in the surgical group, there was less variation in the postural APPD compared to the conservative group, and when there was no variation in the postural APPD, the need of surgery was 100%. The limitation of our study was the small sample size (n = 36). A study involving a larger population or involving multiple institutions may further add significance to our findings.

CONCLUSION

We found less postural variation in APPD on USG to be more likely associated with severe UPJO requiring early surgery. This may indicate a non-compliant renal pelvis. However, it was statistically not significant.

Does Age Influence the Functional Recovery after Infant Pyeloplasty?

Purpose

The purpose was to study the correlation between age at surgery and functional recovery after infant pyeloplasty.

Materials and Methods

All infants who underwent pyeloplasty were analyzed retrospectively in this multicenter study. Anteroposterior diameter (APD) >2 cm, split renal function (SRF) <40%, and Society of Fetal Urology (SFU) grade 3-4 were surgical indications. Based on the age at pyeloplasty, they were divided into Group 1 (1-3 months) and Group 2 (4-12 months). APD and SRF were compared before and after surgery in both groups. The fractional recoverable function (post-SRF-pre-SRF)/(50-pre-SRF) ×100 was correlated with age.

Results

Fifty-one infants underwent pyeloplasty (mean age: 1.6 months - Group 1 and 7.2 months - Group 2). The mean APD decreased from 3 cm to 1.2 cm in Group 1 while 2.8 cm to 2 cm in Group 2 (P = 0.001). The mean SRF increased from 32.28% to 42.81% in Group 1 while 31%-34.18% in Group 2. SRF recovery was significantly higher in Group 1 compared to Group 2 (P = 0.001). Regression analysis showed a weak negative correlation (r = -0.2792) between age at surgery and renal function improvement.

Conclusion

Functional recovery after pyeloplasty is better when done earlier (1-3 months), as this gives the growing kidney the best opportunity to recover.

Can we improve the usefulness of the diuretic renogram in the diagnosis of ureteropelvic junction obstruction (UPJO) in children? Introduction of mercaptoacetyltriglycine-suspected obstruction scoring system (MAG-SOS)

INTRODUCTION

Mercaptoacetyltriglycine (MAG-3) renogram is one of the gold standard diagnostic tools of ureteropelvic junction obstruction (UPJO); however, there is no widely agreed indications of pyeloplasty based on MAG-3 findings. In this study, we introduce a renogram scoring system that can help improve the prognostic value of MAG-3 renogram and in the decision making of pyeloplasty.

PATIENTS AND METHODS

We retrospectively reviewed consecutive pyeloplasties for antenatal hydronephrosis from 2010 to 2020. A control group was included of non-operatively managed SFU grade 3 and 4. The initial renal ultrasound and preoperative MAG-3 Lasix renogram were reviewed for differential renal function (DRF), type of renogram curve and tracer washout half-time (T1/2). A ROC curve was used to evaluate the cut-off points that can be associated with obstruction. A multivariate linear regression model was used to assess the best renogram parameter that can predict surgical intervention.

RESULTS

We included 188 patients with 209 renal units. The median age for pyeloplasty was 5.4 months. The mercaptoacetyltriglycine-Suspected Obstruction Scoring System (MAG-SOS) was associated with pyeloplasty (AUC = 0.97, P < 0.001) (Figure A). A score of 5 is 100% specific for obstruction. 78% of units required surgical intervention had a MAG-SOS score of≥5 while all units of the control group had a range of score 0-4. Using the multivariate analysis, the MAG-SOS system showed to the only independent predictor for pyeloplasty (HR = 0.03, p < 0.001).

DISCUSSION

This study has some limitations. Firstly, the retrospective nature of the cohort; however, all patients were reviewed by one investigator who was blinded to the line of management. This is a single institutional study; therefor, this MAG-SOS should be evaluated by other centers to ensure its efficiency. Lastly, the pyeloplasty decision was taken by 3 different urologists; nevertheless, all of them adopt the same indications which are similar to those of the Society for Pediatric Urology and the Canadian Urological Association guidelines.

CONCLUSION

The MAG-SOS system showed to be a useful tool that can predict pyeloplasty. A score of 5 has 100% specificity for patients having a pyeloplasty performed. Prospective studies are required to confirm the usefulness of this novel tool.

Outcome analysis of immediate and delayed laparoscopic pyeloplasty in infants with severe ureteropelvic junction obstruction

OBJECTIVE

The treatment timing of ureteropelvic junction obstruction (UPJO) in infants remains controversial. This study aimed to compare the recovery effect of renal morphology of immediate and delayed laparoscopic pyeloplasty in infants with severe UPJO.

METHODS

The infants with severe UPJO-induced hydronephrosis who underwent laparoscopic pyeloplasty according to their age at the time of surgery [the immediate treatment (IT) group: ≤1 month of birth, the delayed treatment (LT) group: 3-6 months of birth] in our center between 2010 and 2019 were enrolled in this study. Ultrasonography was used to assess renal morphology, including anteroposterior diameter (APD) of a pelvic, parenchymal thickness (PT), polar length (PL), and Society of Fetal Urology (SFU) grade. Preoperative and postoperative renal morphological outcomes at 6, 12, and 24 months were measured and compared.

RESULTS

During this period, a total of 135 patients were assigned to receive either IT (n = 73) or LT (n = 62) and were included for analysis. There were no significant differences in renal morphology indices at baseline between groups of IT and LT. The APD, PT, and PL in both groups all recovered to certain degrees compared with those at baseline, however, the IT group recovered more significantly than the LT group. Despite there being no significant difference in SFU grade between the two groups before and after surgery, the reduction of SFU grade in the IT group was more significant than that in the LT group during the 6-, 12- and 24-month follow-up periods. The PL, SFU, and APD were greater in the IT group than in the LT group at 6, 12, and 24 months of follow-up. At 6 months PL was not significantly higher between the two groups, while the outcome was significantly different at 12 months and 24 months.

CONCLUSION

Immediate laparoscopic pyeloplasty for the infant with severe ureteropelvic junction obstruction is effective, and it can accelerate the recovery of renal morphological indices in infants with severe UPJO-induced hydronephrosis.

Validation of modified diuretic drainage times criteria in congenital hydronephrosis

INTRODUCTION AND OBJECTIVE

The value of diuretic renography drainage times in congenital hydronephrosis (AHN) decision making is controversial. Recently, a group suggested a modification to the classically described diuretic drainage time cut-off values. They found that a drainage half-time (T_1/2) < 5 min was normal whereas a T_1/2 exceeding 75 min predicted pyeloplasty. In addition, they reported on the benefit of a delayed drainage image obtained with gravity assistance. We sought to evaluate the ability of these modified T1/2 criteria to predict pyeloplasty, alone or in combination with a delayed drainage image referred to as Global Washout (GWO).

METHODS

We retrospectively reviewed 113 patients, including consecutive pyeloplasties for AHN from 2004 to 2018. Patients who underwent pyeloplasty due to low differential renal function (DRF) < 30% or infection were excluded. The control group comprised high grade AHN managed non-operatively. The initial renal ultrasound and MAG 3 Lasix renogram were reviewed for grade, differential renal function (DRF), T_1/2 and GWO. A ROC curve was used to evaluate the T_1/2 and GWO cut-off points that can predict pyeloplasty, using a p-value of less than 0.05.

RESULTS

The pyeloplasty group consisted of 62 patients and the control group consisted of 51 patients. Two patients (3%) in the pyeloplasty group had a T_1/2 < 5 min whereas 21 (34%) had T _1/2 > 75 min (p < 0.001). In the control group, 25 patients (49%) had T _1/2 < 5 min and none had T_1/2 >75 min (P < 0.001). The ROC curve for T_1/2 < 5 min demonstrated 94% sensitivity and 51% specificity whereas a T_1/2 >75 min demonstrated 100% specificity and 34% sensitivity. Analysis of the GWO using a ROC curve revealed that a cut-off of 50% GWO has 100% specificity and 52% sensitivity for pyeloplasty. Overall, a T1/2 > 75 min or GWO <50% predicted 53% of pyeloplasties (Fig A) and was absent in all conservatively managed cases.

DISCUSSION

The limitations of the present study include its retrospective nature. Secondly, the lack of a gold standard diagnostic test for uretero-pelvic junction obstruction hampers objective quantification of diagnostic test utility performance.

CONCLUSIONS

We confirm the utility of the modified diuretic half-time criteria and delayed gravity assisted imaging. A T1/2 > 75 min or GWO <50% are indicators of severity whereas a T1/2 of <5 min or GWO >90% is reassuring. Gravity assisted delayed imaging can be especially helpful in cases with indeterminate T 1/2 times and should be included in the standard assessment of hydronephrotic kidneys. These parameters can be used to tailor the frequency and invasiveness of imaging within observation protocols.

Comparative analysis of suturing technique in pediatric pyeloplasty on surgical outcomes

PURPOSE

Pyeloplasty for ureteropelvic junction obstruction is the gold standard for surgical repair. There are currently no reports outlining optimal suturing technique. This paper compares the effect of suturing technique in dismembered pediatric pyeloplasty (open and laparoscopic) on post-operative outcomes.

METHODS

A non-concurrent cohort study assessed different suturing techniques in both open and laparoscopic dismembered pyeloplasty performed two senior urologists at a tertiary referral pediatric center. Cases were stratified according to different suturing techniques for ureteropelvic anastomosis and subgroup analysis was performed according to open or laparoscopic approach.

RESULTS

A total of 185 renal units were evaluated. The overall comparative analysis of different anastomotic suturing techniques and clustered analysis according to open and laparoscopic approach showed no significant differences on post-operative complication rate, leakage, stenosis, redo-pyeloplasties, operative time and hospital stay. There was a significant difference between suturing techniques on stent duration, age and weight of the patient. There was no effect of suture type or size on post-operative complication rate, leakage, UPJ stenosis and redo pyeloplasty rates, however, sample sizes were small.

CONCLUSION

Suturing technique has no significant effect on the surgical outcomes assessed regardless of open or laparoscopic technique.

Uretero-Pelvic Junction Stenosis: Considerations on the Appropriate Timing of Correction Based on an Infant Population Treated with a Minimally-Invasive Technique

There is no univocal consensus about timing of intervention and best surgical approach for infants with asymptomatic uretero-pelvic junction obstruction (UPJO). We conducted a retrospective analysis of patients undergoing one-trocar-assisted pyeloplasty (OTAP) in a 13 year range period by creating two homogenous groups (indications for surgery were the same for all patients): patients operated on in the first 90 days of life (34 patients; Group 1) and patients operated on between 3 and 12 months of life (34 patients; Group 2). We observed no statistically significant differences between groups in regard to mean operative time, conversion rate to open surgery, mean hospital stay, early complications (urinary leakage) rate and mean antero-posterior diameter (APD) reduction rate. Moreover, no statistical improvement was seen between groups in regard to separate renal function (SRF) at 1-year-follow-up renogram. Thanks to the HSS calculated before and 1 year after surgery, we registered an important improvement in Group I patients (p = 0.023). In our study, there was no significant evidence, in terms of intraoperative data and early postoperative outcomes, between patients who underwent an early pyeloplasty and those who underwent a delayed correction. Nevertheless, we registered a significant improvement in those patients with an impaired SRF that underwent an early surgical correction, especially in terms of urinary flow. Even though this study cannot definitely establish the superiority of early timing of correction, it is evident that further research is needed to clarify this aspect.

Early pyeloplasty versus conservative management of severe ureteropelvic junction obstruction in asymptomatic infants

BACKGROUND

Ureteric-pelvic junction obstruction (UPJO) is the most common cause of antenatal and neonatal hydronephrosis and its management remains controversial. While conservative management is advocated for all, this strategy puts a quarter of these patients at risk for possibly irreversible renal damage.

AIM

In this study, we compare functional and anatomic outcomes in newborns and infants less than 1 year of age with high-grade unilateral UPJO, following early surgical pyeloplasty (ESP) versus conservative management (CM).

MATERIALS AND METHODS

This was a single center prospective interventional study. Infants referred to our tertiary care pediatric surgery clinic between September 2016 and September 2018 with UPJO were considered. To be included patients must have been less than 1 year old, lack of clinical symptoms, suffer from severe hydronephrosis as defined by Society for Fetal Urology (SFU) grades 3 or 4, and have affected kidney Split Renal Function (SRF) above 40%. Patients with bilateral disease, structural anomalies, or an abnormal voiding cystourethrogram (VCUG) were excluded. Anatomical and functional outcomes were measured and compared at 6 and 12 months.

RESULTS

Fifty-six patients were assigned to receive either ESP (n = 28) or CM (n = 28). At 6 months Cortical thickness, polar length, and SFU indices were significantly lower in the ESP group, while none of the outcomes were significantly different between the two groups at 12 months. Despite the two groups not being different at 12 months regarding differential renal function (DRF), there was a significant decrease of function in the CM group compared to baseline.

CONCLUSION

When considering treatment options for infants with high-grade UPJO, it appears that ESP hastens improvement of anatomic and functional indices, while CM may lead to a significant deterioration in renal function.

Diuretic Enhanced Ultrasonography in the Diagnosis of Pyeloureteral Obstruction

Background and Objectives: To determine the value of diuretic ultrasonography for the diagnosis of obstructive hydronephrosis. Materials and Methods: Diuretic enhanced ultrasonography was used routinely as a part of examination of patients with hydronephrosis in our Department. There were 72 patients (42 males, 30 females; aged 2 months to 17 years; median age 7.07 years) with a sonoscopic diagnosis of hydronephrosis included from January 2006 until October 2011. The anteroposterior diameter (AD) of renal pelvis was measured sonoscopically before and at sixty minutes after furosemide injection. A weight-adjusted dose of 1 mg/kg of furosemide was administered intravenously. Results: Patients were operated on if pyeloureteral obstruction was suspected because of low or deteriorating differential renal function, increasing hydronephrosis or symptoms thereof. Hydronephrosis was unilateral in 61 (84.7%) and bilateral in 11 (15.3%) patients. The median AD of pelvis before furosemide injection was 22 mm in operated and 17 mm in non-operated patients (p = 0.005). Sixty minutes after furosemide injection, the AD of pelvis in operated patients was 35.5 mm and 25.8 mm in non-operated—25.8 mm (p < 0.001). Logistic regression model demonstrated that significant factors for surgery were: AD 60 min after furosemide infection and ultrasonographic parenchymal sclerosis. Conclusion: Ultrasound measurement of the AD of renal pelvis 1 h after the injection of furosemide used as an additional investigation can help in predicting obstructive hydronephrosis.

Does the use of 5 mm instruments affect the outcomes of robot-assisted laparoscopic pyeloplasty in smaller working spaces? A comparative analysis of infants and older children

INTRODUCTION

Pediatric robot-assisted laparoscopic (RAL) pyeloplasty has become a viable minimally invasive surgical option for ureteropelvic junction obstruction (UPJO) based on its efficacy and safety. However, RAL pyeloplasty in infants can be a challenging procedure because of the smaller working spaces. The use of the larger 8 mm instruments for these patients instead of the 5 mm instruments is common because of the shorter wrist lengths.

OBJECTIVE

We hypothesized that the use of 5 mm instruments for RAL pyeloplasty in infants with smaller working spaces will have comparable perioperative parameters and surgical outcomes in comparison with older children with larger working spaces.

STUDY DESIGN

We compared the perioperative parameters and surgical outcomes of RAL pyeloplasties performed by a single surgeon in infants and non-infant pediatric patients over a 2 year period. All of the procedures were performed using an 8.5 mm camera and 5 mm robotic instruments. Patient demographics, operative times, perioperative complications, hospital pain medication usage, hospital length of stay, and treatment success rates were compared between the two groups.

RESULTS

A total of 65 pediatric RAL pyeloplasties were included in the study (16 infants and 49 non-infants, Table). There were no significant differences in gender, laterality, proportion of re-do pyeloplasty, or preoperative hydronephrosis grade between the two groups. All procedures were performed without conversion to open surgery or significant perioperative complications. There were no differences in segmental operative times (total operative time, console time, port placement time, time for dissection to UPJO, and anastomosis time), hospital pain medication usage, and hospital length of stay between the two groups (p > 0.05 for all comparisons). The treatment success rates were 93.8% (15/16) and 100% (49/49), respectively (p = 0.08).

DISCUSSION

We present the first comparative study of infant and non-infant pediatric RAL pyeloplasty using 5 mm robotic instruments. An advantage of the current study is the use of a single surgeon's experience to compare RAL pyeloplasty outcomes in infants with those of older children, a group in which RAL pyeloplasty has already been shown to be efficacious and safe. Operative tips for infant RAL pyeloplasty are also provided.

CONCLUSIONS

RAL pyeloplasty is a safe and effective surgical modality even in infants, with comparable perioperative parameters and outcomes as those in older children. The use of 5 mm instruments in infants does not affect outcomes and offers the potential for improved cosmesis.

Primary non-surgical management of unilateral ureteropelvic junction obstruction in children: a systematic review

Ureteropelvic junction obstruction (UPJO) is the most common obstructive uropathy and its optimal management remains controversial. However, there is a current trend towards non-surgical management. We aimed to determine the effects of the non-surgical management in children with unilateral UPJO. For a systematic review, we searched MEDLINE, EMBASE, CENTRAL, clinical trials registries, and selected conference proceedings for eligible studies. Any type of study reporting the outcomes renal function, secondary surgical intervention, drainage pattern or hydronephrosis of non-surgical management in children with unilateral UPJO was included. Data from 20 studies were extracted and evaluated by two independent authors. The pooled prevalence was 21% for split renal function deterioration, 27.9% for secondary surgical intervention, 3.2% for progressive hydronephrosis, and 82.2% for improved drainage pattern. Not all patients with surgical intervention regained split renal function from enrolment. Renal imaging methods did not strongly correlate with each other. Many studies had to be excluded because of a lack of detection of an obstruction or mixed populations with bilateral UPJO or other uropathies. The variable definitions of UPJO, different criteria for surgical intervention, incongruity of management protocols, and the imprecise reporting of outcomes were limiting factors in the comparability of the results, leading to heterogeneity in meta-analyses. Although the available evidence cannot recommend or refute the current non-surgical management, the systematic review clarifies aspects of the ongoing controversy by providing realistic estimates for non-surgical management in children with unilateral UPJO. Additionally, it reveals unclear potential risks, particularly for long-term outcomes, which were rarely reported.

Imaging in children with unilateral ureteropelvic junction obstruction: time to reduce investigations?

The objective of the study was the development of an abridged risk-stratified imaging algorithm for the management of children with unilateral ureteropelvic junction obstruction (UPJO). Data on timing, frequency and duration of diagnostic imaging in children with unilateral UPJO was extracted retrospectively. Based on these findings, an abridged imaging algorithm was developed without changing the intended management by the clinicians and the outcome of the individual patient. The potential reduction of imaging studies was analysed and stratified by risk and management groups. The reduction in imaging studies, seen for ultrasound (US) and functional imaging (FI), was 45% each. On average, this is equivalent to 3 US and 1 FI studies less for every patient within the study period. The change was more pronounced in the low-risk groups. Progression of UPJO never occurred after 2 years of age and all secondary surgeries were carried out until the age of 3.

CONCLUSIONS

Although our findings need to be validated by further prospective research, the developed imaging algorithm represents a risk-stratified approach towards less imaging studies in children with unilateral UPJO, and a follow-up beyond 3 years of age should be considered only in selected cases at the discretion of the clinician. What is Known: • ultrasound and functional imaging represent an integral part of therapeutic decision-making in children with unilateral ureteropelvic junction obstruction • imaging studies cannot accurately assess which patients are in need of surgical intervention, therefore close, serial imaging is preferred What is New: • a new, risk-stratified imaging algorithm was developed for the first 3 years of life • applying this algorithm could lead to a considerable reduction of imaging studies, and also the associated risks and health-care costs.

Is it Always Necessary to Treat an Asymptomatic Hydronephrosis Due to Ureteropelvic Junction Obstruction?

The postnatal treatment of asymptomatic unilateral hydronephrosis due to ureteropelvic junction obstruction remains controversial, and the timing of and indications for surgical intervention are continuously debated. There is no consensus on the best follow-up during expectant management. The various modalities and parameters have been discussed along with their pros and cons and an attempt has been made to clear up the controversies.

Functional outcomes of early versus delayed pyeloplasty in prenatally diagnosed pelvi-ureteric junction obstruction

Although initial conservative management is popular in the management of antenatally detected pelvi ureteric junction (PUJ) obstruction [1-3], several authors [4,5] have questioned this approach and expressed concern about failure to recover the function lost during expectant management following surgery. In this single center prospective study, we have compared the functional outcomes following early versus delayed pyeloplasty in SFU grade 3-4 PUJ obstruction.

METHODS

Among those children, who presented between 2004 and 2013, with prenatal diagnoses of unilateral PUJ obstruction (n = 886), those with SFU grade 1 or 2 hydronephrosis on USG (n = 533) were excluded. In the remaining 353 children with SFU grade 3 and 4 hydronephrosis, 243 had obstructive pattern on radionuclide scan. After excluding those with severely impaired or supranormal split renal function (SRF), palpable mass, single kidney status, bilateral disease and associated other urological anomalies a total of 126 children were included in the study group. Parents who were unwilling for a frequent follow-up underwent early pyeloplasty, (Group I: n = 62) while the remaining underwent initial conservative management, with 3 monthly USG and nuclear scans (Group II; n = 64). In this group pyeloplasty was performed whenever there was deterioration in SRF >10%, or urine infection or pain during the follow-up. A standard open dismembered pyeloplasty was performed by the same surgeon in all patients. Radionuclide scan was performed at 1 year, at the same center using the same protocol, to assess final SRF and drainage. The functional outcomes were compared using student's t test and chi square test.

RESULTS

Group I comprised of 62 patients while Group II 64 patients. The mean age at pyeloplasty was 2.8 months in group I while 12.5 months in group II. There was no significant difference in the initial antero posterior diameter (APD) between the groups; 30.2 (±3.2) mm in group I and 29.6 (±3.7) mm in group II. At 1-year follow up after surgery, there was improvement in the APD, 16.8 (±4.2) mm in group I and 18.2 (±4.5) mm in group II, with no significant difference between them. In group I, the initial mean SRF was 34.1% (±6.4) and there was significant improvement (p = 0.01) in mean SRF to 37.2 (±7.1) at 1-year follow up after surgery. In group II, the mean SRF was 35.9 (5.7) initially and there was a deterioration to 32.6 (±5.5) before surgery (Figure). At 1-year follow up after surgery, there was a marginal improvement to 33.5 (5.6), however it was significantly lower compared to the initial SRF (p = 0.01). Compared to initial function, at 1-year follow up after pyeloplasty, SRF improved in significantly higher number of patients; 17/62 (27.4%) in group I while only 7/64 (10.9%) in group II (p = 0.03) (Table). There was significantly fewer patients with deterioration in final SRF at 8/62 (12.9%) in group I compared to 22/64 (34.4%) in group II (p = 0.03).

DISCUSSION

Although several publications [1-3] have reported functional recovery during initial conservative treatment of PUJ obstruction, in our study a large proportion of patients (80%) in Group II had loss of function during follow-up. This is probably because the study population included only SFU grade 3-4 with obstructive renogram. Several authors have expressed concern about irreversible loss of renal function during expectant management [4,5]. Findings of our study reveal that irrespective of initial SRF, early pyeloplasty in prenatally diagnosed SFU grade 3-4 PUJ obstruction leads to significant improvement of SRF, while delayed pyeloplasty leads to a marginal but, significant loss. This fact should be highlighted to parents so that informed decisions can be made regarding early versus delayed surgery.

Long term outcome of management of antenatally diagnosed pelvi-ureteric junction obstruction

OBJECTIVE

To evaluate the outcome of children with antenatally detected unilateral pelvi-ureteric junction obstruction (PUJO).

METHODS

Children with antenatally diagnosed hydronephrosis, postnatally, unequivocally proven to be due to PUJO, with a normal contralateral kidney were evaluated. Children with atleast 2 y of follow-up were included in the study. The children were divided into early pyeloplasty (those who underwent pyeloplasty at presentation) and conservative (who were managed conservatively). Children in conservative group, who required pyeloplasty during follow up, constituted the delayed pyeloplasty group and those who are still being managed conservatively constituted the no surgery group. The outcome was compared in between these groups in terms of relative function of the affected kidney, drainage pattern and pelvicalyceal dilatation.

RESULTS

A total of 30 children with a mean follow up of 43.3 mon were enrolled in the study. Of the 30 patients, ten had undergone early pyeloplasty and the remaining 20 were managed conservatively. Of these 20, 8 had undergone delayed pyeloplasty and the remaining 12 constituted no surgery group. Overall, 40% of patients in the present study had not required pyeloplasty till the end of the study period. The renal function in early pyeloplasty and conservative group was maintained or improved. Delayed pyeloplasty was able to restore the function in those operated for fall in function to the level that was seen at presentation. The change in renal function in between the early and delayed pyeloplasty groups was not statistically significant (p 0.97).

CONCLUSIONS

The conservative management of PUJO, in renal unit with good function, does not lead to any significant deterioration in the function even when delayed pyeloplasty is performed, when indicated. Two-fifths of the patients may not require pyeloplasty at all.

When is it necessary to perform nuclear renogram in patients with a unilateral neonatal hydronephrosis?

PURPOSE

To examine whether anteroposterior(AP) pelvic diameter on postnatal renal ultrasound scan (US) can predict both initial differential renal function (DRF) and deterioration in DRF in patients with prenatally diagnosed hydronephrosis.

METHODS

One hundred and thirty-three patients diagnosed with a unilateral prenatal hydronephrosis, confirmed postnatally, were evaluated. We tried to find the cutoff values for initial AP diameter and change in AP diameter based on initial DRF and renal outcome. Reduction of 5% or more was considered as deterioration in function. All patients had an initial US scan at a mean age of 1.62 weeks (1-4) and nuclear renogram at 13.24 weeks (7-21). All patients had a second US at a mean age of 10.58 weeks (6-19). 119 patients had a second renogram.

RESULTS

Initial mean pelvic diameter was 20.86 (11-49) mm. When AP pelvic diameter was less than 20 mm, 98.6% of all renal units had a function of ≥40%. The cutoff point for AP pelvic diameter was 19.05 when DRF was ≥45% (P < 0.001). When the reduction in hydronephrosis in pelvic diameter was analyzed to predict the initial renal function, a cutoff point of 1.3 mm decrease was found when initial renal function was ≥40% (P < 0.001). The reduction in AP pelvic diameter was 2.1 mm when initial DRF was ≥45% (P = 0.009). For all patients except 3 individuals, if there was a reduction in AP diameter or the AP diameter was stable, then no reduction in function was observed.

CONCLUSION

When the AP pelvic diameter is less than 20 mm at presentation, DRF is normal. If the AP diameter is stable or decreases, there is unlikely to be a significant deterioration in renal function. Consequently, in selected patients, congenital unilateral hydronephrosis can be followed with serial ultrasounds.

Unilateral anomalies of kidney development: why is left not right?

Abnormal renal development results in congenital anomalies of the kidney and urinary tract. As many studies suggest that renal malformations are more often found on the left side, a meta-analysis was performed on the distribution of five different unilateral anomalies: multicystic dysplastic kidney, renal agenesis/aplasia, renal ectopia, pelviureteral junction obstruction, and non-obstructive non-refluxing megaureter. Of these anomalies, the left side was affected in 53%, 57%, 56.9%, 63.2%, and 62.5% of patients, respectively, significantly different when compared with an anticipated 50% of left-sided anomalies. An exception to this left-side predominance was found in females with combined genital anomalies and unilateral renal agenesis that commonly present on the right side. The exact mechanisms leading to these lateralizations remain to be determined but may involve vascular development, differential gene expression, or susceptibility to environmental factors such as hypoxia. This remains largely speculative, however, illustrating our limited knowledge of embryogenesis in general and nephrogenesis in particular.

[Postnatally hydronephrosis (HN) in children with antenatally diagnosed hydronephrosis: surgery or medical treatment?]

OBJECTIVES

There is no formal agreement or criteria utilized to establish a standard of treatment in children with antenatally diagnosed HN.

METHODS

We analyzed our own experience in addition to the protocols attending to this subject. Twenty eight (28) children with unilateral HN were assessed from October 1999 through October 2005 and the anteroposterior diameter of renal pelvis (APDP) was measured.

RESULTS

Patients underwent surveillance with US and cintilography in 3, 6, 12 and 24 months. The treatment results were reviewed following the classification of Society of Fetal Urology: slight (2 to 5 mm), moderate (6 to 10 mm) and severe (> 10-15 mm).

CONCLUSIONS

We concluded that slight HN would never be operated on while the severe ones would always be. The moderate HN, on the other hand, would remain under surveillance with US and cintilography for two years.

International Scientific Committee of Radionuclides in Nephrourology (ISCORN) consensus on renal transit time measurements

This report is the conclusion of the international consensus committee on renal transit time (subcommittee of the International Scientific Committee of Radionuclides in Nephrourology) and provides recommendations on measurement, normal values, and analysis of clinical utility. Transit time is the time that a tracer remains within the kidney or within a part of the kidney (eg, parenchymal transit time). It can be obtained from a dynamic renogram and a vascular input acquired in standardized conditions by a deconvolution process. Alternatively to transit time measurement, simpler indices were proposed, such as time of maximum, normalized residual activity or renal output efficiency. Transit time has been mainly used in urinary obstruction, renal artery stenosis, or renovascular hypertension and renal transplant. Despite a large amount of published data on obstruction, only the value of normal transit is established. The value of delayed transit remains controversial, probably due to lack of a gold standard for obstruction. Transit time measurements are useful to diagnose renovascular hypertension, as are some of the simpler indices. The committee recommends further collaborative trials.

Treatment and outcome of prenatally detected newborn hydronephrosis

OBJECTIVE

For neonates with antenatally diagnosed primary ureteropelvic junction (UPJ)-type hydronephrosis, to attempt to clarify and refine criteria for establishing optimal follow-up and treatment guidelines.

PATIENTS AND METHODS

A total of 162 newborns (228 hydronephrotic kidneys) with this condition were prospectively followed and treated by the same surgeon in 2001-2005 for a mean of 53 (13-72) months. Ultrasonography and diuretic renogram were used for diagnosis and follow up, and Onen's grading system to determine degree of hydronephrosis.

RESULTS

On first postnatal ultrasound, the severity of hydronephrosis was grade 1 in 152 kidneys (surgery, 0%), 2 in 41 (surgery, 19.5%), 3 in 19 (surgery, 42.1%), and 4 in 16 kidneys (surgery, 93.8%). All the grade 1 cases resolved spontaneously without renal deterioration (renal function >40%). Renal function ranged between 7% and 34% in grade 4 patients. Overall, 201 hydronephrotic kidneys (88.2%) resolved spontaneously, while 27 (11.8%) required pyeloplasty because of evidence of obstructive injury, including increased hydronephrosis in 14/27 (6/27 had less than 10% decrease in renal function), greater than 10% decrease of renal function in 9/27, and greater than 10% decrease of renal function as well as increased hydronephrosis in 4/27 patients (15%).

CONCLUSION

In most cases, neonatal hydronephrosis is a relatively benign condition that can be followed safely by an initial non-operative approach unless there is evidence of obstructive injury. A follow-up protocol that permits early identification of a limited number of kidneys that may develop signs of obstruction and require pyeloplasty is crucial for a favorable outcome in patients with primary UPJ-type hydronephrosis. Onen's hydronephrosis grading system promises an easier and more appropriate follow up and timely treatment for children with this condition. A sufficient follow-up interval, especially during the first 3 years of life, is essential to help prevent permanent loss of renal function in kidneys that do develop signs of obstruction.

[Prenatal diagnosis of hydronephrosis: utility of diuretic renography]

OBJECTIVE

To investigate the value of diuretic renography in patients with prenatally diagnosed unilateral hydronephrosis.

MATERIAL AND METHOD

We reviewed 44 patients who underwent ultrasonography in the first week of life and 1 month after birth, and cystography and diuretic renography at 1 month to evaluate differential renal function and the diuretic washout pattern. Patients with vesicoureteral reflux were followed-up according to the protocol for this disorder. In the remaining patients, ultrasonography and/or diuretic renography was performed every 3-6 months.

RESULTS

In 4/44 patients vesicoureteral reflux was detected as cause a of hydronephrosis. In the remaining 40 patients, diuretic renography showed a washout pattern not suggestive of obstruction in 32 (only one patient needed surgery due to pyohydronephrosis). An indeterminate washout pattern was detected in one patient (who required surgery due to worsening of the washout pattern). A pattern suggestive of obstruction was detected in seven patients, four of whom required surgery (three due to a decrease in differential renal function and one due to worsening of the degree of pelvic dilatation).

CONCLUSIONS

Diuretic renography is highly useful in risk stratification and in the management of newborn infants with hydronephrosis since infants with washout patterns not suggestive of obstruction will rarely develop obstructive hydronephrosis and can initially be followed-up with ultrasonography alone. In indeterminate and obstructive patterns, however, close monitoring that includes diuretic renography is mandatory.

Conservative Treatment of Ureteropelvic Junction Obstruction in Children with Antenatal Diagnosis of Hydronephrosis: Lessons Learned after 16 Years of Follow-Up

OBJECTIVES

We attempted to define predictive factors for surgery in children with antenatal diagnosis of hydronephrosis that led to postnatal diagnosis of ureteropelvic junction (UPJ) obstruction.

METHODS

We retrospectively evaluated our 16-yr experience (1988-2003) with 343 children (260 male and 83 female) with antenatal diagnosis of hydronephrosis that led to postnatal diagnosis of UPJ obstruction and who were followed conservatively. Right-sided hydronephrosis was present in 110 and left-sided in 233 children. According to the Society for Fetal Urology (SFU) classification none had grade 0 of postnatal hydronephrosis, 20 had grade 1, 118 grade 2, 147 grade 3, and the remaining 58 children grade 4 postnatal hydronephrosis. Relative renal function (RRF) on radionuclide scans revealed 235 children with RRF>40%, 68 with RRF between 30% and 40%, and 40 patients with RRF<30%. Renal function deterioration >5% was the main indication for surgery. Commercially available software GraphPad Prism 4.0 (GraphPad prism, Prism 4 for Windows, version 4) using the Fisher exact test was used for statistical evaluation.

RESULTS

Surgical correction was needed in 179 children (52.2%) during the course of conservative management. The average age at surgery was 10.6 mo (range, 1 mo to 7 yr). Of those, 50% underwent surgery during the first 2 yr of life and the majority of the remaining patients underwent surgery between the 2 and 4 yr of age; only two patients required surgery later on. Univariate analysis revealed that child sex, side of hydronephrosis, and SFU grade of prenatal hydronephrosis were not significant predictive factors for surgery. However, SFU grade 3-4 of postnatal hydronephrosis (p<0.0001; odds ratio, 0.06281) and RRF<40% (p<0.0001; odds ratio, 0.1022) were significant independent risk factors for surgery.

CONCLUSION

In contrast with previous publications by others and by us these data show that >50% of children with antenatal diagnosis of UPJ obstruction in this series required surgical correction while on conservative protocol. SFU grade 3-4 of postnatal hydronephrosis and RRF<40% are significant independent predictive factors for surgery.

Congenital unilateral hydronephrosis: a review of the impact of diuretic renography on clinical treatment

PURPOSE

The natural history of and optimal treatment for asymptomatic congenital hydronephrosis is unknown, mainly because most published series are nonrandomized or retrospective with nonstandardized followup regimens. In this survey we provide an overview of the different strategies used for the treatment of congenital unilateral hydronephrosis.

MATERIALS AND METHODS

A comprehensive literature review of clinical studies of asymptomatic congenital unilateral hydronephrosis is presented.

RESULTS

Different criteria for surgical intervention and different followup regimens have been used. Identification of the population at risk has been attempted but results are ambiguous. Surgery is done in approximately 25% of cases when using deteriorating differential function, symptoms and/or increasing hydronephrosis as criteria for operation. A nonstandardized renographic assessment does not compromise evaluation of the ideal followup but it may compromise the functional outcome.

CONCLUSIONS

More studies of kidneys with decreased function, severe hydronephrosis or poor drainage investigated with a standardized protocol are needed to clarify the natural history and establish optimal guidelines for treatment and followup.

Insights into the pathogenesis and natural history of fetuses with renal pelvis dilatation

Fetal renal pelvis dilatation is a frequent abnormality that has been observed in 4.5% of pregnancies. The majority of these cases have a tendency to resolve during infancy. Nevertheless, fetal renal pelvis dilatation may be due to significant structural abnormalities such as pelvi-ureteric junction stenosis or vesico-ureteral reflux that may adversely affect renal function or cause urinary infection or sepsis. This review article aims to summarize the data regarding fetal renal pelvis dilatation and to analyze controversial attitudes in the light of the various lines of practice, and to present rational antenatal and postnatal investigation strategy.

Upper urinary tract: when is obstruction obstruction?

PURPOSE OF REVIEW

Obstruction can either be defined as a condition that hampers optimal renal development, or, more conservatively, as a restriction to urinary outflow that, when left untreated, will cause progressive renal deterioration. Currently, management is mostly based on the latter definition, but still remains controversial. Relevant work published before 2002 is considered because of a lack of recent literature.

RECENT FINDINGS

Almost all reports comparing the primary conservative treatment of suspected obstruction versus early surgical intervention show comparable results, but there are different interpretations. The approach of 'watch and wait' for a unilateral hydronephrotic kidney with normal function is usually quite safe, with a very low risk of the permanent loss of renal function when accompanied by close monitoring, but it is certainly not without risk. At this time, the main underlying problems are that all currently applied diagnostic methods only detect effects secondary to obstruction, and the currently used definition of obstruction is based on a longitudinal observation period. The most relevant publication in the observation period was an in-depth report on a workshop in which the need for valid prospective markers for renal maldevelopment and 'significant' obstruction was expressed.

SUMMARY

The optimal management of infants with congenital hydronephrosis and suspected obstruction will remain controversial until new diagnostic methods are able to discriminate between 'harmful' and 'harmless' obstruction. Most experts currently advocate primary conservative management, with close follow-up and surgical intervention only if there are signs of reduced function of the obstructed kidney.

Perinatal obstructive nephropathy

Significant advances have been made recently in elucidating the cellular consequences of urinary tract obstruction during renal development. Urinary tract obstruction impairs growth and maturation of the kidney, and can also cause renal maldevelopment. This includes a reduction in the number of nephrons, tubular atrophy, and progressive interstitial fibrosis. Apoptosis (programmed cell death) accounts for much of the loss of tubular epithelial cells. Factors contributing to apoptosis include stretching of cells in dilated tubules, altered renal production of growth factors, and infiltration of the renal interstitium by macrophages. Two major controversies remain regarding the surgical management of congenital obstructive nephropathy: first, which fetuses with bladder outlet obstruction should undergo prenatal intervention, and second, which infants should undergo early pyeloplasty for ureteropelvic junction obstruction? Even after successful surgery for congential obstructive nephropathy, all patients should be followed for hypertension, proteinuria, or renal deterioration.

Ureteropelvic junction obstruction in children: two variants of the same congenital anomaly?

OBJECTIVE

To compare the characteristics of prenatally and postnatally diagnosed ureteropelvic junction obstruction (UPJO) in children.

PATIENTS AND METHODS

We reviewed the records of 74 children who underwent pyeloplasty or nephrectomy for UPJO between 1995 and 2000. The patients were divided into 2 groups: prenatally and postnatally diagnosed UPJO. In each group, we compared age at surgery, gender, affected side, anteroposterior diameter (APD) of the renal pelvis, surgical findings, and renal function as determined by creatinine clearance.

RESULTS

Of the 74 children, 44 (59.4%) had a prenatal diagnosis of UPJO and 30 (40.6%) had a postnatal diagnosis despite the fact that all had had a fetal ultrasonography. Median age at the time of surgery was 6.3 years (4 months to 16 years) for children with postnatal UPJO and 3.6 months (1 month to 4 years) for the prenatal group. Forty-three percent of the children in the postnatal group and 25% in the prenatal group were females. Clinical manifestations in children with postnatal UPJO included abdominal pain in 13 (43%) patients, pyelonephritis in 7 (23%), urinary tract infection in 5 (16.6%), and occasional findings upon ultrasound in 5 (16.6%). Excretory urography suggested obstruction in most children. The surgical findings included ureteral kinks due to adhesions in 93.3% of postnatally diagnosed UPJO cases and in 27.3% of prenatal cases (p < 0.01). A reduction in mean creatinine clearance of hydronephrotic kidneys was observed for both groups when compared to reference values for the respective ages, but this difference was not statistically significant.

CONCLUSIONS

Postnatally diagnosed UPJO may be considered, at least in part, an entity different from prenatally detected obstruction due to its peculiar characteristics, i.e., postnatal UPJO more frequently affects females, manifests later in life with urinary infection or abdominal pain, and is frequently associated with ureteral kinking.

Unilateral urinary flow impairment at the pelviureteral junction: outcome of renal function with respect to therapeutic strategy

OBJECTIVES

To evaluate the renal function outcome in children with unilateral hydronephrosis and urinary flow impairment at the pelviureteral junction with respect to the therapeutic strategy.

METHODS

We retrospectively selected 45 children with iodine-123-hippuran renography performed at diagnosis and after 3 or more years of follow-up. All children had bilateral nonobstructive pattern findings on diuretic renography at follow-up. Eleven children were treated conservatively, and 34 underwent unilateral pyeloplasty. Split and individual renal function, measured by an accumulation index, was computed from background-corrected renograms for the affected and contralateral kidneys at diagnosis and the follow-up examination.

RESULTS

Of 11 children treated conservatively, 9 had normal bilateral function at diagnosis, all had reached normal function at follow-up. Of the 34 operated kidneys, 12 (38%) had initially normal function that remained normal at the follow-up examination, and 22 had impaired function that had normalized at the follow-up examination in 15 (68%). The function of the contralateral kidneys was increased in 5 of 8 children with persistently abnormal affected kidneys. Pyeloplasty was performed in 23 children (68%) and 11 children (32%) younger and older than 1 year, respectively. The function of the affected kidneys increased in both groups, but normalization occurred only in the younger children.

CONCLUSIONS

Of the children selected for conservative treatment, 82% had normal bilateral renal function at diagnosis that was normal in all at the follow-up examination. Of the children treated surgically, 65% had initially impaired function of the affected kidney that improved in 87% after pyeloplasty. Normalization of function was observed only in children who were younger than 1 year old at surgery. Persistently low function of the affected kidney was compensated for by the contralateral one regardless of the age at surgery.

Does delaying pyeloplasty affect renal function in children with a prenatal diagnosis of pelvi-ureteric junction obstruction?

OBJECTIVE

To evaluate retrospectively children with an antenatal diagnosis of pelvi-ureteric junction (PUJ) obstruction who required pyeloplasty for deteriorating renal function during the follow-up, specifically assessing the recovery of function after surgery.

PATIENTS AND METHODS

Between 1988 and 2000, 44 consecutive patients with a prenatal diagnosis of PUJ obstruction who were initially treated by observation underwent pyeloplasty because their renal function deteriorated during the follow-up. Patients with bilateral disease, a single kidney or vesico-ureteric reflux were excluded from the study. The mean (sd) age of the patients was 13.3 (4.5) months and their mean (range) initial renal function 39.7 (30.4-45)%. In all patients the diagnostic criteria and indications for surgery were identical. The main indication for surgery was deteriorating renal function of >5%, confirmed by renal scintigraphy. Of 44 patients, 35 (77%) had severe dilatation of the renal pelvis by >3 cm. The mean (sd) deterioration in renal function during the follow-up, just before surgery, was 8.2 (2.4)%, and the mean time between the last acceptable renogram and the study showing deterioration was 8.3 (1.3) months; the mean follow-up was 5.1 (1.6) years. The results were assessed statistically using the unpaired nonparametric Mann-Whitney U-test.

RESULTS

An improvement in hydronephrosis was confirmed in all patients, with renal function returning to the initial levels in 36 of 44 (81%) patients 6-12 months after surgery, although in two patients renal function did not improve after surgery. There was no significant difference between the preoperative characteristics and the degree of hydronephrosis, renal function or patient age with the level of renal functional improvement after surgery.

CONCLUSION

In patients with an antenatal diagnosis of PUJ obstruction, expectant management is recommended and spares the children unnecessary surgery. Even if renal function deteriorates, delayed pyeloplasty recovers the initial functional level.

Successful early pyeloplasty in infants

BACKGROUND

Early pyeloplasty for the treatment of congenital ureteropelvic junction obstruction to maximize nephron salvage is justified only if potential hazards of operating on small infants are avoided.

METHODS

The records were analyzed of all infants who underwent pyeloplasty over a 5-year period. Open pyeloplasty was performed if collecting systems had deteriorated or were demonstrated to be obstructed; it was also performed for severe cases of hydronephrosis. Outcome of surgery in the younger infant (patients <2 months of age) was compared with the older infant group (patients >2 months of age). Preoperative evaluation in case of mild or moderate hydronephrosis was directed toward ruling out a non-obstructed collection system and included voiding cystourethrography, and serial ultrasonography and/or dual isotope diuretic renography. Postoperative assessment consisted of serial ultrasonography and/or nuclear imaging to confirm decompression and relief of obstruction.

RESULTS

A total of 24 pyeloplasties were performed on 22 patients in the younger infant group (two bilateral) and 30 were performed on 27 infants in the older infant group (three bilateral). The only significant differences between the groups were as follows: patients in the younger infant group were likely to present in utero (75%, p = 2.69), whereas those in the older infant group were more likely to present with a urinary tract infection (48%, p = 4.12). During follow-up examination, 23 renal units in the younger infant group and 24 in the older infant group were judged to be stable or improved. Four kidneys were not salvaged after pyeloplasty, one in the younger infant group and three in the older infant group.

CONCLUSIONS

Good results of pyeloplasties performed in the infants in this series support early correction of ureteropelvic junction obstruction in infants.

Prenatal diagnosis: does it alter outcome?

The prenatal detection of urinary tract anomalies is changing paediatric practice but in many areas the impact on clinical outcome remains difficult to quantify. However it is already apparent that termination of pregnancy has reduced the numbers of infants with lethal pulmonary hypoplasia and renal dysplasia who would previously have been liveborn but destined to succumb as neonates. Similarly, referrals of major non lethal abnormalities such as bladder exstrophy are declining as parents increasingly opt for termination. Fetuses at greatest risk of early onset postnatal renal failure can now be identified with considerable accuracy on prenatal ultrasound. Termination, prompted by quality of life considerations, could result in reduced numbers of infants and young children requiring end stage renal failure treatment in the first few years of life. Pre natal detection of anomalies such as PUJ obstruction and reflux undoubtedly provides an opportunity to avert functional deterioration and minimise urinary infection. But the proportion of children who genuinely benefit has proved difficult to assess. The prenatal detection of mild dilatation is of doubtful benefit in all but a minority of cases. Clinically significant underlying pathology is rare yet this common prenatal finding often generates disproportionate parental anxiety.

Prenatal hydronephrosis

Prenatal hydronephrosis is diagnosed with an incidence of 1:100 to 1:500 maternal-fetal ultrasonographic studies. Although ultrasonography accurately describes dilation of the renal collecting system, it cannot define mechanical obstruction, a functional characteristic. The purpose of prenatal screening has changed from simple detection of hydronephrosis to selection for specific diagnosis-based management. The natural history of prenatal hydronephrosis is difficult to determine, and therefore physicians who take care of the fetus and infant are challenged with the following question: when does dilation of the renal collecting system indicate that serious pathology (ongoing renal deterioration) exists? The diagnosis of prenatal hydronephrosis, indications for and timing of prenatal intervention, and recommendations for treating children with a history of prenatal hydronephrosis are included in this review.

The long-term followup of newborns with severe unilateral hydronephrosis initially treated nonoperatively

PURPOSE

During the last decade it has become apparent that prenatally detected, unilateral severe hydronephrosis does not necessarily represent obstruction and may spontaneously improve or resolve postnatally. To define its natural history better we performed a long-term (mean 78 months) followup study of infants with hydronephrosis.

MATERIALS AND METHODS

A total of 104 newborns with antenatally diagnosed, primary, unilateral severe hydronephrosis were followed nonoperatively unless evidence of renal deterioration occurred for which pyeloplasty was performed.

RESULTS

All 23 infants (22%) who required pyeloplasty were younger than 18 months and had progressive hydronephrosis and/or reduction in differential renal function. Differential function exceeded predeterioration levels in all kidneys postoperatively. Of those cases followed nonoperatively hydronephrosis resolved in 69% and improved in 31%. Mean time to maximum improvement of hydronephrosis was 2.5 years. In 76% of those cases followed nonoperatively initial differential function was greater than 40% and final function averaged 49%. In the remaining 24% of cases differential function was less than 40% (mean 23%), and in an average of 18 months differential function increased to a mean of 47%. Initial half-time in nonoperative cases was greater than 30 minutes in 37%, 20 to 30 in 21% and less than 20 in 42%. Final half-time was greater than 30 minutes in 16%, 20 to 30 in 17% and less than 20 in 67%. Half-time was greater than 30 minutes in 87% of the patients and 20 to 30 in 4% before, and greater than 30 in 10%, 20 to 30 in 27% and less than 20 in 63% after pyeloplasty.

CONCLUSIONS

Unilateral newborn hydronephrosis appears to be relatively benign and in most instances dilatation and renal function improve with time. However, close followup is necessary to identify the subgroup of less than 25% of infants with obstruction because prompt pyeloplasty will prevent permanent loss of renal function. Standard tests for assessing obstruction in older patients appear to be invalid in infants because prolonged half-time and/or high grade hydronephrosis is neither an indicator of obstruction or surgery. Nonoperative treatment with close followup especially during the first 2 years is safe and recommended for these children.