Neonatal management. Role for early intervention

Prediction of Neonatal Respiratory Distress Biomarker Concentration by Application of Machine Learning to Mid-Infrared Spectra

The authors of this study developed the use of attenuated total reflectance Fourier transform infrared spectroscopy (ATR–FTIR) combined with machine learning as a point-of-care (POC) diagnostic platform, considering neonatal respiratory distress syndrome (nRDS), for which no POC currently exists, as an example. nRDS can be diagnosed by a ratio of less than 2.2 of two nRDS biomarkers, lecithin and sphingomyelin (L/S ratio), and in this study, ATR–FTIR spectra were recorded from L/S ratios of between 1.0 and 3.4, which were generated using purified reagents. The calibration of principal component (PCR) and partial least squares (PLSR) regression models was performed using 155 raw baselined and second derivative spectra prior to predicting the concentration of a further 104 spectra. A three-factor PLSR model of second derivative spectra best predicted L/S ratios across the full range (R²: 0.967; MSE: 0.014). The L/S ratios from 1.0 to 3.4 were predicted with a prediction interval of +0.29, −0.37 when using a second derivative spectra PLSR model and had a mean prediction interval of +0.26, −0.34 around the L/S 2.2 region. These results support the validity of combining ATR–FTIR with machine learning to develop a point-of-care device for detecting and quantifying any biomarker with an interpretable mid-infrared spectrum.

Renal-on-Chip Microfluidic Platform with a Force-Sensitive Resistor (ROC-FS) for Molecular Pathogenesis Analysis of Hydronephrosis

Hydronephrosis is one of the most common diseases in urology. However, due to the difficulties in clinical trials and the lack of reliable in vitro platforms, the surgical indicators are not clear. Herein, the renal-on-chip with a force-sensitive resistor microfluidic platform was established to simulate the state of hydronephrosis. Cell counting kit-8 (CCK-8) and tight junction protein claudin-2 were detected on a renal-on-chip microfluidic platform with a force-sensitive resistor (ROC-FS). The results indicated that the ROC-FS had normal physiological functions and the cell viability on ROC-FS declined to around 40% after 48 h of hydronephrosis-simulated treatment. In addition, proteomics analysis of 15 clinical ureteropelvic junction obstruction (UPJO) samples showed that compared with normal children, a total of 50 common proteins were differentially expressed in UPJO children (P < 0.05, |log₂fold change| ≥ 1). Metabolomic analysis of 39 clinical UPJO samples showed that a total of 241 metabolisms were dysregulated. Subsequent immunofluorescence and enzyme-linked immunosorbent assay (ELISA) analysis using ROC-FS were performed to identify the clinical multi-omics results for screening. All results pointed out that the TGF-β-related signaling pathways and arginine-related metabolism signaling pathways were dysregulated and α-SMA, AGT, and AGA might be the potential biomarkers of hydronephrosis. In addition, correlation analysis of AGT and KLK1 with differential renal function (DRF) from clinical samples indicated good correlation coefficients (R² 0.923, 0.8742, 0.6412, and 0.8347). This demonstrates the state of hydronephrosis could be significantly correlated with the biomarkers. These findings could provide a reliable reference for determining surgical biomarkers clinically, and ROC could be further used in the analysis of other kidney diseases.

Safe discharge parameters for patients with isolated antenatal hydronephrosis

INTRODUCTION

Antenatal hydronephrosis is a steady source of urology referrals since the era of routine fetal ultrasonography. Although most resolve, there are no guidelines for follow-up.

OBJECTIVE

Our goal is to define safe parameters with which patients can be discharged early and avoid unnecessary follow-up.

METHODS

We retrospectively reviewed all patients referred to a single children's referral hospital center for isolated antenetal hydronephrosis between 2010 and 2012. We looked at patients and renal units separately and divided the cohort into two groups for comparison. Our analysis endpoint is progression. That is, if the initial postnatal anterior-posterior diameter (APD) is less than 10 mm, progression occurs if the APD increases to 10 mm or above upon follow-up. Conversely, if the initial APD is 10 mm or more in at least one renal unit, progression occurs if the APD remains at 10 mm or above upon follow-up.

RESULTS

There majority of the 186 patients and 308 renal units included in the analysis, were classified in the APD less than 10 mm group. Most renal units in the APD of less than 10 mm group were of SFU grades 0-2 (92.1%) and most of the renal units in the APD of 10 mm or greater group were of SFU grades 3-4 (60%) (Table). Only 19 renal units (6.2%) underwent pyeloplasty, and they were all from the APD of 10 mm or greater group and classified as SFU grade 3-4. No renal unit with an APD of less than 10 mm, nor any with an APD of 10 mm or greater and a SFU grade 0-2 underwent pyeloplasty. More than half of the renal units' hydronephrosis resolved in the APD of 10 mm or greater group, in comparison with 96.1% of the APD of less than 10 mm group. On multivariate analysis, patients with an APD of 10 mm or greater were 7.76 times more likely to show progression (p = 0.0006).

CONCLUSION

An initial postnatal APD of 10 mm or greater, with a SFU grade 3-4, merits follow-up. However, all patients with an APD of less than 10 mm, especially when with a SFU grade 1-2, can be safely discharged as they are unlikely to experience complications.

Is urine intercellular adhesion molecule-1 a marker of renal disorder in children with ureteropelvic junction obstruction?

AIM

We aimed to investigate whether urine intercellular adhesion molecule-1 (ICAM-1) might serve as a marker of renal disorder in children with ureteropelvic junction obstruction.

MATERIAL AND METHODS

Twenty-nine children with severe hydronephrosis (HN) were compared with 23 participants with mild HN and with 19 healthy peers.

RESULTS

Urine ICAM-1/uCre levels were significantly higher in HN children than healthy controls (P<0.01), and in severe HN when compared with mild HN (p<0.05).

CONCLUSIONS

It seemed to us that uICAM-1 is a biomarker of renal disorder, and might have the potential to predict which patients will require surgery.

Is a Reassuring MAG-3 Diuretic Renal Scan Really Reassuring?

Objective

The mercaptoacetyltriglycine-3 (MAG-3) diuretic renal scan is frequently used to diagnose obstruction in children with hydronephrosis. However, it remains unclear whether a reassuring MAG-3 diuretic scan in the presence of high-grade hydronephrosis accurately predicts the absence of obstruction. We sought to determine if a reassuring nuclear scan can accurately identify patients with high-grade hydronephrosis that can be safely observed.

Materials and Methods

We retrospectively reviewed the course of 22 children (25 renal units) ages 0-3 months with significant hydronephrosis (Society of Fetal Urology grade 3-4) detected prenatally. All patients underwent a MAG-3 diuretic nuclear renal scan.

Results

Twenty-two patients with 25 renal units were included, 19 with grade 3 and 6 with grade 4 hydronephrosis on ultrasound. Sixteen renal units had a reassuring nuclear scan (T ½ < 10 minutes, average 5.9, range 2-9). Nine renal units had indeterminate scans (T ½ 10-20 minutes, average 12.8, range 10-17). Fifteen of 16 (94%) kidneys with a reassuring nuclear scan had complete resolution of their hydronephrosis. One patient with an initially reassuring nuclear scan underwent pyeloplasty after persistent grade 4 hydronephrosis one year later prompted a repeat MAG-3 indicating obstruction. Eight of 9 (89%) patients with an indeterminate T ½ of 10-20 minutes had complete resolution of their hydronephrosis. One patient was lost to follow up. Average length of follow up and time to resolution was 23.6 months (range 4-61 months).

Conclusion

In pediatric patients with persistent antenatally detected hydronephrosis, a reassuring MAG-3 can allow for safe observation in the vast majority. Only one of 24 renal units with follow-up progressed to obstruction. All patients treated without surgery had complete resolution of their hydronephrosis. Observation with serial ultrasounds may be an appropriate alternative to operative management, even in patients with moderate to severe hydronephrosis in the presence of a reassuring or indeterminate MAG-3 diuretic scan.

Hydronephrosis due to pelviureteric junction narrowing: Utility of urinary enzymes to predict the need for surgical management and follow-up

AIM

To study the role of urinary enzymes N-acetyl-β-glucosaminidase (NAG), alkaline phosphatase (AKP) and gamma glutamyl transferase (GGT) in the diagnosis and follow-up of patients with suspected pelviureteric junction obstruction (PUJO).

MATERIALS AND METHODS

A total of 70 patients, 29 managed conservatively (group A) and 41 managed by pyeloplasty (group B), were studied prospectively. A serial measurement of urinary enzymes NAG, AKP and GGT level was performed in both the groups. The mean levels of these urinary enzymes were compared between the two groups and among the patients of the same group at presentation as well as during follow-up.

RESULTS

There was a significant fall in the mean AKP level in patients managed conservatively at 8 months of follow-up. Similarly, in the operated group, there was a significant fall in the AKP levels at both 3 months and 8 months of follow-up. The mean level of GGT also showed a significant fall after 3 months of surgery but did not show further significant change at 8 months after surgery. The mean levels of NAG and GGT in the conservatively managed group were significantly low compared with that of patients requiring pyeloplasty at presentation as well as in the follow-up. The mean level of AKP was significantly low in the conservatively managed group when compared with the patients requiring surgery, but did not differ significantly in both the follow-ups after surgery.

CONCLUSIONS

The level of urinary enzymes NAG, AKP and GGT are significantly high in the patients with hydronephrosis (HDN) requiring pyeloplasty when compared with the patients managed conservatively. The level of AKP significantly falls after pyeloplasty in the patients of HDN due to PUJO. There is a negative correlation with the preoperative level of enzyme NAG with split renal function in the patients of HDN requiring pyeloplasty.

Probability of urinary tract infection in infants with ureteropelvic junction obstruction: is antibacterial prophylaxis really needed?

In infants with ureteropelvic junction obstruction (UPJO), the risk of urinary tract infection (UTI) is unknown, and there is a lack of prospective studies showing definitive evidence regarding the benefits and necessity of antibiotic prophylaxis. The aim of this study was to assess the risk of UTI in infants with UPJO and to determine whether the risk varies according to the degree of hydronephrosis. Infants with hydronephrosis detected prenatally or within the postnatal 28th day and who had no previous history of UTI were followed prospectively without antibacterial prophylaxis. Imaging studies were performed according to our Pediatric Uro-Nephrology Study Group protocol. Dimercaptosuccinate (DMSA) scintigraphy was performed in all infants at the end of 1 year of follow-up. Eighty-four infants (56 boys, 28 girls) were included in the study. The distribution of patients in each hydronephrosis grading group was incidentally similar. Within a median follow-up period of 18 (12-24) months, none of the patients had UTI. Furthermore, no pyelonephritic scar was found on DMSA scans in any patient. We conclude that prophylactic antibiotic usage is not indicated in infants with UPJO, regardless of the severity of hydronephrosis, as the risk of UTI is minimal in this population.

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.

Role of urinary biomarkers in the diagnosis of congenital upper urinary tract obstruction

Background:

Congenital obstructive uropathy constitutes a significant cause of morbidity in children. Currently, there is no reference standard for the diagnosis of renal obstruction in children. The noninvasive measurement of biomarkers in voided urine has considerable appeal as a potential application in children with congenital obstructive nephropathy. The aim of the present review is to explore the current role of biomarkers in the diagnosis and follow-up of obstructive uropathy in children.

Materials and Methods:

The literature database (PubMed) was searched from inception to May 2007 regarding the role of urinary biomarkers in the diagnosis and follow-up of children with congenital obstructive uropathy.

Results:

The review included 23 experimental and 33 prospective controlled clinical studies. Several cytokines, peptides, enzymes and microproteins were identified as major contributors to or ensuing from obstruction-induced renal fibrosis and apoptosis. The most important biomarkers were transforming growth factor-β₁ (TGFβ₁), epidermal growth factor (EGF), endothelin-1 (ET-1), urinary tubular enzymes [N-acetyl-β-D-glucosaminidase (NAG), γ-glutamyl transferase (GGT) and alkaline phosphatase (ALP)], and microproteins [β₂-microglobulin (β₂M), microalbumin (M. Alb) and micrototal protein (M.TP)]. All biomarkers showed different degrees of success but the most promising markers were TGFβ₁, ET-1 and a panel of tubular enzymes. These biomarkers showed sensitivity of 74.3% to 100%, specificity of 80% to 90% and overall accuracy of 81.5% to 94% in the diagnosis of congenital obstructive uropathy in children. Moreover, some of the markers were valuable in differentiation between dilated non-obstructed kidneys in need of conservative management and obstructed kidneys in need of surgical correction. Some studies demonstrated that urinary biomarkers are helpful in the evaluation of success of treatment of children with congenital renal obstruction. Some limitations of the previous studies include lack of different types of controls and small sample size. Larger studies with variable controls are invited to confirm the clinical usefulness of biomarkers in the diagnosis and follow-up of children with congenital obstructive uropathy.

Conclusion:

Urinary biomarkers are a promising tool that could be used as a noninvasive assessment of congenital renal obstruction in children.

Management of severe bilateral ureteropelvic junction obstruction in neonates with prenatally diagnosed bilateral hydronephrosis

PURPOSE

The management of prenatally detected bilateral ureteropelvic junction obstruction (UPJO) remains controversial. We attempted to develop a treatment plan for patients with severe bilateral UPJO.

MATERIALS AND METHODS

We evaluated the records of 13 patients with prenatally diagnosed grade 3 or more bilateral hydronephrosis that led to the postnatal diagnosis of severe bilateral UPJO. Ultrasonography and (99m)technetium mercaptoacetyltriglycine ((99m)Tc-MAG3) renal scans were performed within 1 month. Four renal units had grade 3 and 22 had grade 4 hydronephrosis. All 13 patients were managed by unilateral pyeloplasty, and the patients' mean age was 3 months. At 1 month postoperatively, we decided whether delayed surgery in the opposite renal unit was necessary according to the findings of ultrasonography and (99m)Tc-MAG3 scans.

RESULTS

Of 13 patients, 11 underwent initial pyeloplasty on renal units with more severe hydronephrosis or lower relative renal function (RRF) on (99m)Tc-MAG3 scans. The remaining 2 patients simultaneously underwent percutaneous nephrostomy on renal units with a lower RRF and initial pyeloplasty on renal units with a higher RRF. In 5 patients, contralateral hydronephrosis had spontaneously improved at 1 month postoperatively, and 8 patients underwent delayed contralateral pyeloplasty at 2 months postoperatively.

CONCLUSIONS

In children with severe bilateral UPJO, the non-operated renal units with grade 3 and some with grade 4 hydronephrosis improved spontaneously after unilateral pyeloplasty. Therefore, delayed pyeloplasty of the opposite side should be considered at 1 month following initial pyeloplasty.

Results of a practical protocol for management of prenatally detected hydronephrosis due to ureteropelvic junction obstruction

INTRODUCTION

Several algorithms exist for the management of prenatally diagnosed hydronephrosis due to ureteropelvic junction obstruction (UPJO). We utilize a conservative and practical approach emphasizing observation, with less frequent use of renal flow scans (RFS). We reviewed the results of 143 pediatric patients with congenital UPJO managed at our institution, focusing on surveillance and selective utilization of RFS, according to a standardized protocol.

MATERIALS AND METHODS

Charts of all infants with prenatally detected UPJO treated surgically or followed conservatively according to our protocol were reviewed. Patients were initially evaluated with ultrasound (US), voiding cystourethrogram, and RFS. Successive follow-up was with interval US. RFS was reserved for those with worsening hydronephrosis or that which failed to improve on US by 1 year. Radiographic studies and operative reports were examined. Gender, side of UPJO, degree of hydronephrosis, mode of management, and current status of the patients were noted.

RESULTS

The records of 143 patients and a total of 198 renal units (RU) were reviewed. The male:female ratio was 2.7. UPJO was unilateral in 88 (61%) patients and occurred more frequently on the left side (68%). Obstruction was bilateral in 55 (39%) patients. Initial US grade of hydronephrosis was Grade 1 in 56 RU (28%), Grade 2 in 51 RU (26%), Grade 3 in 50 RU (25%) and Grade 4 in 41 RU (21%). 178 RU (90%) were followed conservatively, while open dismembered pyeloplasty was the initial therapeutic approach in 20 RU (10%). The mean age at the time of surgery was 15.95+/-14.60 weeks (range 2-60). Indications included low differential renal function (DRF) (n=12), absence of tracer clearance from the renal pelvis (n=2), parental preference (n=3), and acute renal failure (n=3). Postoperative course was uneventful during 33.43+/-33.53 months (range 2-120) with favorable US and RFS results. In conservatively managed patients, mean follow-up time was 14.94+/-14.35 months (range 1.5-142). Spontaneous resolution of hydronephrosis was observed in 87 RU (49%), while 10 RU (5.6%) eventually required surgery for worsening appearance or function on US or RFS, respectively (n=8), symptom development (n=3), and/or parental preference due to persistently prolonged T1/2 (n=4). Seventy-two RU (40.4%) remain under surveillance with improvement (47.2%) or stable hydronephrosis (47.2%) in 94.4%. Decreased DRF occurred in 1 RU. Nine RU (5%) were lost to follow-up. With application of this algorithm, only 12% of patients underwent two or more RFS.

CONCLUSION

Pyeloplasty may be performed safely in infants when indicated; however, the majority of children with UPJO can be managed conservatively. Spontaneous resolution of hydronephrosis and/or favorable prognosis was encountered in 87% of conservatively managed RU. The use of a standard US grading system, selective utilization of follow-up renal function testing, and parental compliance are important factors in successful management.

Hydronephrosis in infants and children: natural history and risk factors for persistence in children followed by a medical service

Background:

Infants with neonatal hydronephrosis and a normal voiding cystourethrogram (VCUG) are presumed to have ureteropelvic junction obstruction (UPJO). There is little current information about the natural history of children with hydronephrosis or clinical factors that predict resolution of the radiological abnormality.

Objective:

To determine the time course until spontaneous resolution of neonatal hydronephrosis and define risk factors for persistence of the abnormality.

Methods:

This retrospective single center review examined infants and children <5 years of age with hydronephrosis who were followed for at least 12 months.

Results:

136 children were identified (96 male:40 female). The mean age at diagnosis of hydronephrosis was 3.3 ± 9.7 months and 76% of the patients were diagnosed at birth. The hydronephrosis was unilateral in 98 (72%) of cases, and hydronephrosis was at least moderate in severity in 22% of affected kidneys. At last follow-up at 30 ± 10 months, the abnormality had resolved in 77 out of 115 (67%) available patients, 30 (26%) had been referred to urology, and 12 (10%) had persistent hydronephrosis. Severity of hydronephrosis was the only clinical feature that predicted persistence of the abnormality (P < 0.001). There was an association between detection at birth and lack of resolution of hydronephrosis.

Conclusions:

Children with hydronephrosis and presumed UPJO and normal kidney parenchyma can be followed for at least 2 years to allow for spontaneous resolution before referral to urology. Serial sonography can be performed at 6 month intervals in uncomplicated cases. More severe hydronephrosis and presence of the lesion at birth may predict infants and children requiring closer observation and referral for possible surgical correction of the hydronephrosis.

Obstructed Versus Dilated Nonobstructed Kidneys in Children With Congenital Ureteropelvic Junction Narrowing: Role of Urinary Tubular Enzymes

PURPOSE

We evaluated the role of voided urine lysosomal enzyme N-acetyl-beta-D-glucosaminidase and brush border enzymes alkaline phosphatase and gamma-glutamyl transferase in differentiating between children with ureteropelvic junction obstruction in need of pyeloplasty and those with dilated nonobstructed kidneys suitable for conservative treatment.

MATERIALS AND METHODS

The study included 35 children with unilateral ureteropelvic junction obstruction treated with pyeloplasty (study group) and 15 children with dilated nonobstructed kidneys who were treated conservatively and followed for 15 months (control group). Voided urine samples were obtained before treatment from both groups, and from the study group at 1, 2, 3, 6, 9 and 12 months postoperatively and the control group at 3, 9 and 15 months of followup. N-acetyl-beta-D-glucosaminidase, alkaline phosphatase and gamma-glutamyl transferase were measured in urine samples collected from both groups.

RESULTS

In the study group the activities of preoperative urinary N-acetyl-beta-D-glucosaminidase, alkaline phosphatase and gamma-glutamyl transferase were significantly higher than in the control group. A cutoff value of 7.8 mU/mg creatinine N-acetyl-beta-D-glucosaminidase yielded a sensitivity of 97.1%, a specificity of 80% and an overall accuracy of 92%. A cutoff value of 34.5 IU/gm creatinine alkaline phosphatase resulted in a sensitivity of 91.4%, a specificity of 100% and an overall accuracy of 94%. A cutoff value of 54 IU/gm creatinine gamma-glutamyl transferase yielded a sensitivity of 62.9%, a specificity of 100% and an overall accuracy of 74%. The combination of urinary N-acetyl-beta-D-glucosaminidase and alkaline phosphatase resulted in a sensitivity of 100%, a specificity of 80% and an overall accuracy of 94%. Compared to preoperative activities, N-acetyl-beta-D-glucosaminidase, alkaline phosphatase and gamma-glutamyl transferase decreased significantly at 12 months after pyeloplasty in the study group.

CONCLUSIONS

Voided urinary N-acetyl-beta-D-glucosaminidase, alkaline phosphatase and gamma-glutamyl transferase are accurate markers for differentiating between children with ureteropelvic junction obstruction requiring pyeloplasty and those with dilated nonobstructed kidneys suitable for conservative treatment. Measurement of these enzymes in voided urine could be used as a noninvasive tool for long-term followup of children with ureteropelvic junction obstruction after pyeloplasty and those receiving conservative treatment.

Pattern of renal function deterioration as a predictive factor of unilateral ureteropelvic junction obstruction treatment

OBJECTIVES

To assess the process of renal function deterioration in patients with unilateral ureteropelvic junction (UPJ) obstruction and its impact on their treatment course.

MATERIAL AND METHODS

The files of patients treated for unilateral UPJ obstruction at our department from 1996 to 2003 were retrospectively reviewed. All patients were initially treated conservatively and followed up regularly. Criteria for conversion to surgical treatment were increase in anteroposterial renal pelvis diameter, increase in T(1/2) washout pattern, and drop of relative renal function (RRF) below 40% in diuretic renogram. Patients operated on because of multiple urinary infections, pelvic stones, or solitary kidneys were excluded. Patients were divided into group A, which included those whose treatment was converted from conservative to surgical, and group B in which patients were treated conservatively. All patients operated on underwent dismembered pyeloplasty.

RESULTS

Sixty-four patients with grade three or four hydronephrosis in postnatal ultrasound examination and an obstructive pattern in diuretic renogram were studied. All group A patients (n=47) reached an RRF below 40%; in 41 (87.2%) deterioration of RRF was detected in at least two sequential follow-up studies. In group B patients (n=17), deterioration was also detected in seven (41.1%) patients in two sequential studies (p<0.0005), although the RRF never dropped below 40%. No differences in gender, side of obstruction, or frequency of follow-up were detected between the two groups.

CONCLUSIONS

RRF deterioration and its progression for at least two sequential follow-ups could serve as a predictive factor for surgical treatment.

Ureteropelvic junction obstruction in children: 10 years' experience in one institution

We reviewed our experience over 10 years with pyeloplasty for ureteropelvic junction obstruction. Preoperative and postoperative isotope renal scans were performed to assess the surgical outcome, with particular emphasis on the postoperative change in renal function (RF). We retrospectively reviewed the medical records of 137 consecutive children with ureteropelvic obstruction operated between January 1994 and December 2003. A total of 109 kidneys in 102 patients were evaluated with renal echo and (99m)Tc-diethylenetriaminepentaacetic renography both before and after Anderson-Hynes dismembered pyeloplasty. The improvement of RF >5% was noted in 67 kidneys (61.5%), the function remained stable in 30 kidneys (27.5%), and it deteriorated (>5%) in 12 kidneys (11.0%). Five patients (4.6%) required repeat pyeloplasty for either prolonged urine leakage or reobstruction with deterioration in RF. Dismembered pyeloplasty in children with ureteropelvic junction obstruction is safe. The renal functional improvement can be expected in the majority of kidneys that have impaired function at presentation.

Management of neonatal hydronephrosis

Management of neonatal hydronephrosis is a clinical challenge. The natural history of hydronephrosis has shown that most resolve spontaneously; however, there are a significant number that do not. Although hydronephrosis does not always mean obstruction, it becomes the clinician's role to determine when obstruction will eventually lead to renal damage. Work-up of hydronephrosis diagnosed prenatally starts with a postnatal ultrasound. Using the Society of Fetal Urology (SFU) grading of hydronephrosis based on ultrasonography, a management and treatment algorithm can be constructed. Other studies include a voiding cystourethrogram to evaluate for vesicoureteral reflux or in severe cases of bilateral hydronephrosis to evaluate for posterior urethral valves. Diuretic renography is useful in many cases to evaluate the degree of obstruction and determine differential renal function. The goal is to select the patients who would benefit from early surgical intervention. To achieve that goal, aggressive observation is often required.

Postnatal unilateral pelviureteral junction obstruction: impact of pyeloplasty and conservative management on renal function

OBJECTIVES

To study the effect of pyeloplasty and conservative management on renal function in children with pelviureteral junction obstruction.

METHODS

This prospective study included 65 children postnatally diagnosed with unilateral pelviureteral junction obstruction. On the basis of the patients' symptoms and technetium-99m diethylenetriamine pentaacetic acid renal isotope scan findings, symptomatic patients or those with split function of the corresponding kidney of 40% or less were assigned to group 1 (n = 35) and underwent pyeloplasty. Asymptomatic patients with split function greater than 40% (group 2, n = 30) were treated conservatively. Patients who showed deterioration of renal function underwent pyeloplasty. The effect of both lines of treatment on renal function was evaluated.

RESULTS

After pyeloplasty, group 1 had improvement in the glomerular filtration rate (GFR) in 30 (85.7%), stabilization in 2 (5.7%), and deterioration in 3 (8.6%) patients. In group 1, the comparison between the mean value of the baseline GFR (17.1 +/- 7.7 mL/min) and its mean value at follow-up (28 +/- 6.3 mL/min) showed an increase of statistical significance (P <0.01). In the group 2 patients, conservative treatment resulted in improvement in the GFR in 12 (40%), stabilization in 3 (10%), and deterioration in 15 (50%) patients. In group 2, no significant difference was found between the mean baseline GFR (29.8 +/- 9.8 mL/min) and its mean value at follow-up (31.2 +/- 5.6 mL/min).

CONCLUSIONS

In patients with postnatal pelviureteral junction obstruction, early pyeloplasty is recommended if the corresponding GFR is 40% or less. Conservative management in patients with better function resulted in deterioration of renal function in 50%. Should this policy of treatment be chosen, meticulous follow-up is mandatory.

Moderate approach to the antenatally diagnosed unilateral ureteropelvic junction obstruction: experience with 93 patients

To evaluate the results of the treatment in patients with antenatally detected unilateral ureteropelvic junction obstruction. Ninety-three patients were analyzed according to the radiologic and scintigraphic findings and mode of the treatment. Fifty-eight patients were treated surgically while 29 patients were followed conservatively. All patients were reevaluated at the first year of the treatment with diuretic renogram (DR). Follow-up procedure was finished at first postoperative year in surgically treated patients, while mean follow-up duration was 14.9+/-6.9 months for the conservatively treated group. In the operated group, pelvic diameter was greater than 20 mm on ultrasound and overall rate of mean split renal function was 38.65+/-9.55% on DR and 39.65+/-12.55% at first postoperative year. In the conservatively treated group, mean split renal function was 46.17+/-3.42 at the beginning and 47.48+/-4.00 at first year of follow-up. Sixty-three percent of the patients underwent pyeloplasty while 83% of them were showing obstructive pattern on DR. We believed that surgery should be done in renal units which showed pelvic diameter greater than 20 mm and less than 40% of split renal function, while others might be followed conservatively, with or without an obstructive pattern on DR.

BIOMARKERS OF CONGENITAL OBSTRUCTIVE NEPHROPATHY: PAST, PRESENT AND FUTURE

PURPOSE

Congenital obstructive nephropathy constitutes one of the major causes of renal insufficiency in infants and children. This review addresses the need to define biomarkers that serve as surrogate end points for measuring the severity of obstruction, the evolution of renal maldevelopment and injury, and the response to medical or surgical intervention.

MATERIALS AND METHODS

The literature from the last 10 years was reviewed for biomarkers of congenital obstructive nephropathy. Sources of biomarkers included urine, blood, amniotic fluid, tissue and imaging techniques.

RESULTS

Previous markers of congenital obstructive nephropathy include sonographic renal pelvic diameter, quantitative diuretic renography, and markers of glomerular and tubular function. Attempts to correlate renal histological changes with differential renal function have been disappointing. Immunohistochemical analysis and laser capture microscopy should improve specificity. Most promising is the application of new insights into the cellular response of the developing kidney to urinary tract obstruction. These findings include components of the renin-angiotensin system, transforming growth factor-beta 1, monocyte chemoattractant protein-1 and epidermal growth factor. Microarray studies show unique patterns of gene expression by the neonatal rat kidney subjected to ureteral obstruction, and proteomics should provide even more sensitive biomarkers of obstructive nephropathy.

CONCLUSIONS

We must define the cellular and molecular bases of renal maldevelopment, focusing on the link between functional and developmental pathophysiology. These findings will lead to biomarkers that will optimize our management of congenital obstructive nephropathy.

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.

Ureteropelvic Junction Obstruction: Some new Acquisitions about Etiology, Pathophysiology and Diagnostics

The etiopathogenesis of uretero-pelvic junction obstruction (UPJO) has been the subject of many speculations and it remains, in some ways, a debatable matter. Some recently reported thorough research refer to neuro-mediated pathogenetic mechanisms rather than (or together with) myogenic ones.

Advances in US, radioisotopic functional imaging, CT and RM contribute to differentiate the obstructive conditions from the non-obstructive ones and to afford today a better assessment of renal functional damage. Particularly, diuretic renography is a non-invasive test for characterization of the renal functional abnormalities resulting from UPJO. Helical CT with angiography is a useful technique for identification of crossing vessels (pyelo-vascular tangle) which can be used for the pre-surgical planning of endopyelotomy. Endoluminal ultrasonography can be used to guide the position of the incision for endopyelotomy (US-guided endopyelotomy).

Laboratory examinations are important to determine the overall renal function (serum creatinine, acid-base balance, serum electrolytes, etc.), urinary MCP-1 and NAG (markers of tubular damage), and to rule out urinary tract infections.

The management of UPJO (watchful waiting; either open or laparoscopic dismembered pyeloplasty; endoluminal procedures) is greatly influenced by the diagnostic evaluation.

The paper aims to outline the advances in both physiopathology and diagnostics of UPJO on the basis of a review of the literature.

[Diuretic renography in the diagnostic approach of prenatal hydronephrosis]

OBJECTIVE

To verify the utility of diuretic renography using 99mTc-MAG3 in the evaluation of the urinary tract obstruction in patients with prenatal diagnosis of hydronephrosis. In a neonate with upper urinary tract dilatation, it is difficult to differentiate a true obstruction from a dilated non-obstructed system.

MATERIAL AND METHODS

The retrospective study (january 1993-december 1998) included 40 consecutive patients selected from 181 newborns with a prenatal diagnosis of hydronephrosis. The mean age of the performance of the first renography was 2.6 months.

RESULTS

The final diagnosis (once the vesicoureteral reflux was ruled out) was: ureteropelvic junction obstruction (UPJ) 16, megaureter 15, ureterocele 3 and stasis 6. Conservative treatment was applied in most of the patients. Nevertheless, 17 of them needed surgical treatment due to the high risk of the permanent renal damage.

CONCLUSIONS

1) UPJ is the most frequent cause of neonatal hydronephrosis (NH) and consequently, of the request for diuretic renographies. The renography with 99mTc-MAG3 has the greatest influence in the therapeutic decision (identifying who should be operated on and when this should be done), due to the fact that it is the disease with the highest rate of surgical interventions. 2). The surgical indication in NH is based on the diuretic renography parameters and/or on the presence of symptomatology. In our series of surgical patients, none of those who had a differential renal function <20% with regard to the contralateral one showed recuperation after surgery (control 6 months later).

[Pyeloureteral junction stenosis: our experience and review of the literature]

OBJECTIVES

To study patients with ureteropelvic junction obstruction treated in our department and a retrospective study of this pathology, focus our attention in the diagnosis and treatment.

MATERIAL AND METHODS

62 patients from 7 weeks to 68 years old (mean 29 +/- 1.9). Half of the patients were men and the other half women. In 30 patients the UPJ obstruction was on the right side and 32 patients was on the left side.

RESULTS

The most frequent symptom was the flank pain (46.8%). To confirm the diagnosis, we had IVU in the 61.3% of the patients and ultrasound in the 38.7%. The treatment was the Anderson-Hynes pyeloplasty in the 96.8% of the patients. In 33 patients we used a ureteral catheter. The overall success rate was 90.3%. The 29% of the patients presented postoperative complications.

CONCLUSIONS

Open pyeloplasty is the gold standard treatment of the UPJ obstruction in selected cases, mainly in children.

Renal function before and after pyeloplasty: does it improve?

PURPOSE

Controversy exists concerning the timing of surgical correction of presumed ureteropelvic junction obstruction. Different opinions on the timing of intervention focus on renal function deterioration with time, poor initial relative function, or obstructive drainage curves and/or drainage time on diuretic renography. We retrospectively determined whether there is any improvement in renal function after pyeloplasty for presumed renal obstruction.

MATERIALS AND METHODS

We retrospectively reviewed the charts of patients who underwent pyeloplasty between 1990 and 1997 in whom preoperative and postoperative diuretic renography data were available. Patients were excluded from review when they had bilateral ureteropelvic junction obstruction, a solitary kidney, associated vesicoureteral reflux, or other bladder or ureteral abnormalities, and when preoperative and postoperative renography studies were not available.

RESULTS

Complete data were available for review in 79 patients 2 weeks to 18 years old (median age 6 months). Of the patients 73% were male and 73% of the affected kidneys were on the left side. Prenatal hydronephrosis had been diagnosed in 58 patients (73%), of whom 19 (33%) were observed for a variable period before pyeloplasty was performed. In all cases diuretic renography performed at the same institution using a standard protocol revealed a drainage time of 20 minutes or greater preoperatively, while in 58 cases a measurable drainage time was never achieved. As a rule, drainage improved postoperatively (mean and median 25 and 16 minutes, respectively). Open renal biopsy done at pyeloplasty in 54 patients was normal in 29. Preoperatively renal function ranged from 5 to 67% (mean and median 41 and 45, respectively). In all patients the paired t test showed no statistical difference in preoperative and postoperative renal function (p = 0.078, 95% confidence interval -3.451 to 0.185). There was no statistical change in renal function in patients with an abnormal renal biopsy regardless of the severity of renal scarring (p = 0.38) or when renal function was 40% or less (mean preoperative versus postoperative 29.7 versus 28.4%, p = 0.46). The group with greater than 40% function preoperatively had no relevant difference in function before or after surgery (mean 49.7 versus 47.8%, p = 0.065). Prenatally screened patients who were initially observed had a statistically significant difference in renal function before and after pyeloplasty (mean 45.6 versus 43%, p = 0.002).

CONCLUSIONS

Renal function did not improve after pyeloplasty regardless of the initial level of relative function. Renal scan revealed that differential function decreased after pyeloplasty in some patients in whom hydronephrosis was detected prenatally and who were initially followed with observation. In our opinion waiting for renal function to decrease before considering pyeloplasty is not warranted, since function does not improve even when obstruction is corrected and drainage time improves.

Renal function before and after pyeloplasty: does it improve?

PURPOSE

Controversy exists concerning the timing of surgical correction of presumed ureteropelvic junction obstruction. Different opinions on the timing of intervention focus on renal function deterioration with time, poor initial relative function, or obstructive drainage curves and/or drainage time on diuretic renography. We retrospectively determined whether there is any improvement in renal function after pyeloplasty for presumed renal obstruction.

MATERIALS AND METHODS

We retrospectively reviewed the charts of patients who underwent pyeloplasty between 1990 and 1997 in whom preoperative and postoperative diuretic renography data were available. Patients were excluded from review when they had bilateral ureteropelvic junction obstruction, a solitary kidney, associated vesicoureteral reflux, or other bladder or ureteral abnormalities, and when preoperative and postoperative renography studies were not available.

RESULTS

Complete data were available for review in 79 patients 2 weeks to 18 years old (median age 6 months). Of the patients 73% were male and 73% of the affected kidneys were on the left side. Prenatal hydronephrosis had been diagnosed in 58 patients (73%), of whom 19 (33%) were observed for a variable period before pyeloplasty was performed. In all cases diuretic renography performed at the same institution using a standard protocol revealed a drainage time of 20 minutes or greater preoperatively, while in 58 cases a measurable drainage time was never achieved. As a rule, drainage improved postoperatively (mean and median 25 and 16 minutes, respectively). Open renal biopsy done at pyeloplasty in 54 patients was normal in 29. Preoperatively renal function ranged from 5 to 67% (mean and median 41 and 45, respectively). In all patients the paired t test showed no statistical difference in preoperative and postoperative renal function (p = 0.078, 95% confidence interval -3.451 to 0.185). There was no statistical change in renal function in patients with an abnormal renal biopsy regardless of the severity of renal scarring (p = 0.38) or when renal function was 40% or less (mean preoperative versus postoperative 29.7 versus 28.4%, p = 0.46). The group with greater than 40% function preoperatively had no relevant difference in function before or after surgery (mean 49.7 versus 47.8%, p = 0.065). Prenatally screened patients who were initially observed had a statistically significant difference in renal function before and after pyeloplasty (mean 45.6 versus 43%, p = 0.002).

CONCLUSIONS

Renal function did not improve after pyeloplasty regardless of the initial level of relative function. Renal scan revealed that differential function decreased after pyeloplasty in some patients in whom hydronephrosis was detected prenatally and who were initially followed with observation. In our opinion waiting for renal function to decrease before considering pyeloplasty is not warranted, since function does not improve even when obstruction is corrected and drainage time improves.

Does early detection of ureteropelvic junction obstruction improve surgical outcome in terms of renal function?

PURPOSE

Prenatal ultrasound leads to the early detection of hydronephrosis. When followed by the early diagnosis of ureteropelvic junction obstruction surgical treatment, if indicated, is associated with minimal morbidity. We attempt to prove the benefits of this therapeutical approach from the point of view of renal function.

MATERIALS AND METHODS

From 1979 to 1997, 452 patients with ureteropelvic junction obstruction underwent dismembered pyeloplasty. Of these patients 113 with comparable data were retrospectively evaluated. Patients were divided into group 1-50 who presented with prenatal hydronephrosis and group 2-63 with neonatal hydronephrosis who were lost to followup and who then presented with symptoms leading to the diagnosis of ureteropelvic junction obstruction. In each group the diagnostic criteria and indications for surgery were identical based on symptomatology, ultrasound and renal scan. Patients with bilateral disease, solitary kidney or vesicoureteral reflux were excluded from study. In groups 1 and 2 median patient age at surgery was 11 months and 5 years, and average postoperative followup was 4.2 and 3.2 years, respectively.

RESULTS

In 41 of the 50 group 1 and 60 of the 63 group 2 patients hydronephrosis was severe and the renal pelvis was more than 3 cm. wide. Poor relative renal function (less than 30%) was significantly more pronounced in group 2 than in group 1 (56 of 63 patients or 89% versus 6 of 50 or 12%, p <0.05). In all 113 patients postoperative followup ultrasound and renal scan revealed significant improvement in hydronephrosis and washout curve pattern. There was a significant difference in the 2 groups in regard to renal function improvement postoperatively (66% of group 1 versus 16% of group 2 patients, p <0.05).

CONCLUSIONS

We believe that patients who undergo prenatal imaging and are diagnosed early with ureteropelvic junction obstruction should be carefully and meticulously followed. Special efforts should be made to ensure that patients are not lost to followup. After any sign of deterioration develops early surgery is indicated. According to our data operative treatment results in improved renal function.

Does early detection of ureteropelvic junction obstruction improve surgical outcome in terms of renal function?

PURPOSE

Prenatal ultrasound leads to the early detection of hydronephrosis. When followed by the early diagnosis of ureteropelvic junction obstruction surgical treatment, if indicated, is associated with minimal morbidity. We attempt to prove the benefits of this therapeutical approach from the point of view of renal function.

MATERIALS AND METHODS

From 1979 to 1997, 452 patients with ureteropelvic junction obstruction underwent dismembered pyeloplasty. Of these patients 113 with comparable data were retrospectively evaluated. Patients were divided into group 1-50 who presented with prenatal hydronephrosis and group 2-63 with neonatal hydronephrosis who were lost to followup and who then presented with symptoms leading to the diagnosis of ureteropelvic junction obstruction. In each group the diagnostic criteria and indications for surgery were identical based on symptomatology, ultrasound and renal scan. Patients with bilateral disease, solitary kidney or vesicoureteral reflux were excluded from study. In groups 1 and 2 median patient age at surgery was 11 months and 5 years, and average postoperative followup was 4.2 and 3.2 years, respectively.

RESULTS

In 41 of the 50 group 1 and 60 of the 63 group 2 patients hydronephrosis was severe and the renal pelvis was more than 3 cm. wide. Poor relative renal function (less than 30%) was significantly more pronounced in group 2 than in group 1 (56 of 63 patients or 89% versus 6 of 50 or 12%, p <0.05). In all 113 patients postoperative followup ultrasound and renal scan revealed significant improvement in hydronephrosis and washout curve pattern. There was a significant difference in the 2 groups in regard to renal function improvement postoperatively (66% of group 1 versus 16% of group 2 patients, p <0.05).

CONCLUSIONS

We believe that patients who undergo prenatal imaging and are diagnosed early with ureteropelvic junction obstruction should be carefully and meticulously followed. Special efforts should be made to ensure that patients are not lost to followup. After any sign of deterioration develops early surgery is indicated. According to our data operative treatment results in improved renal function.