Treatment and outcome of prenatally detected newborn hydronephrosis

Predictors of surgical intervention for antenatally detected ureteropelvic junction obstruction (UPJO): A prospective multivariate analysis

OBJECTIVE

We aimed to identify clinical and radiological predictors of the need for surgical intervention in infants with antenatally detected UPJO.

MATERIAL AND METHODS

We prospectively followed infants born with antenatally diagnosed ureteropelvic junction obstruction (UPJO) presented at our outpatient clinics for evidence of obstructive injury with a standard protocol with ultrasonography and renal scintigraphy. Indications for surgery included progression of hydronephrosis on serial examinations, initial differential renal function (DFR) ⩽35% or >5% loss in sequential studies, and febrile urinary tract infection (UTI). Univariate and multivariate analyses were utilized to define the predictors for surgical intervention, while the appropriate cut-off value of the initial Anteroposterior diameter (APD) was determined using the receiver operator curve analysis.

RESULTS

Univariate analysis revealed a significant association between surgery, the initial APD, cortical thickness, Society for Fetal Urology grade, UTD risk group, initial DRF, and febrile UTI (p-value < 0.05). No significant association between surgery and sex or side of the affected kidney (p-value 0.91 and 0.38, respectively). On multivariate analysis, the initial APD, initial DRF, obstructed renographic curve, and febrile UTI (p-value < 0.05) were the only independent predictors for surgical intervention. An initial APD of 23 mm can predict surgical requirement, with a specificity of 95% and sensitivity of 70%.

CONCLUSION

For antenatally diagnosed UPJO, the APD value (at the age of 1 week), DFR value (at the age of 6-8 weeks), and febrile UTI during follow-up are significant and independent predictors of the need for surgical intervention. APD, when used with a cut-off value of 23 mm, is associated with high specificity and sensitivity for predicting surgical need.

Determination of tissue tracer transit of Technetium-99m-mercaptoacetyltriglycine diuretic renography in infants with suspected ureteropelvic junction obstruction - A multicenter prospective observational study

INTRODUCTION

There is an ongoing controversy regarding management of ureteropelvic junction obstruction in infants, with a shift towards a non-operative approach. However, precise predictors of outcome are lacking. Recent studies postulated a high prognostic value of Technetium-99m-mercaptoacetyltriglycine tissue tracer transit with regard to the development of an impaired differential renal function and its potential improvement following pyeloplasty.

OBJECTIVE

To evaluate the prognostic value of Technetium-99m-mercaptoacetyltriglycine tissue tracer transit for the occurrence of changes in differential renal function in infants with suspected unilateral ureteropelvic junction obstruction in a prospective observational multicenter study.

STUDY DESIGN

Infants below 3 months of age with a unilateral isolated hydronephrosis ≥ grade 3 received ultrasound and Technetium-99m-mercaptoacetyltriglycine diuretic renography at two different time points (timepoint 1 and timepoint 2). Data were analyzed at local centers and at the study center and were collected in an internet-based database system. Tissue tracer transit was determined for each diuretic renography, inter-observer variation for tissue tracer transit and standard parameters for judgement of differential renal function development were assessed.

RESULTS

Thirty-seven patients were analyzed. Median age was 11 weeks (7-15) at timepoint 1 and 26 weeks (19-33) at timepoint 2. A delayed tissue tracer transit at timepoint 1 was not associated with deterioration of differential renal function at timepoint 2 in both, locally (10/37 cases) and centrally (4/37) analyzed cases. However, sensitivity and specificity were poor. The intraclass correlation coefficient comparing local and central findings of tissue tracer transit and renal drainage demonstrated poor or fair agreement. Analysis of standard parameters for differential renal function development revealed a prognostic value only for the dichotomized anteroposterior renal pelvic diameter (APD, p = 0.03, 95%-CI 1.2-22.2).

DISCUSSION

Regarding the primary endpoint of our study, we could not confirm the hypothesis that delayed tissue tracer transit reliably predicts a subsequent decline in differential renal function in the cohort of patients studied. Whether the low age of the patients, technical problems in the correct assessment of tissue tracer transit by the investigator in early infancy, the study design, or the parameter itself played a role is debated.

CONCLUSION

In the presented setting tissue tracer transit was not useful as a predictive parameter for deterioration of differential renal function in infants with suspected unilateral ureteropelvic junction obstruction. Sensitivity and specificity of tissue tracer transit were not sufficient for risk stratification. Improved utility of tissue tracer transit as a marker might be achieved using a different study setting.

Can pyeloplasty restore normal renal function in patients with severe unilateral ureteropelvic junction obstruction and DRF < 35

PURPOSE

To assess the outcome of successful pyeloplasty in infants with Ureteropelvic Junction Obstruction (UPJO) and a differential renal function of (DRF) < 35% whether they can attain normal postoperative renal function or not.

METHODS

All children who were diagnosed with antenatal hydronephrosis due to UPJO were presented to our institutions and were prospectively followed up. Pyeloplasty was performed based on predefined indications such as: initial DRF ≤40%, progression of hydronephrosis, and febrile urinary tract infection (UTI). A total of 173 children, who had successful surgical intervention due to impaired DFR, were divided according to their pre-intervention DRF value as follows: DRF <35% (group I) and DRF 35-40% (group II). The renal morphology and function changes were recorded and used for comparison between both groups.

RESULTS

Group I was comprised of 79 patients, and group II included 94 patients. Pyeloplasty achieved significant improvement in the anatomical and functional indices in both groups (p-value <0.001). The degree of improvement in Anteroposterior diameter (APD) and cortical thickness was comparable in both groups (P-value, 0.64 and 0.44 respectively). While the improvement in the DRF was significantly higher in group I (16.06 ± 6.6) than in group II (6.25 ± 2.66) (P-value <0.001). Despite that, a significantly higher percentage of infants in group II (61.7%) achieved normal final DRF compared with only (10.1%) in group I (Figure).

CONCLUSION

Even in severely impaired renal function (<35%), successful pyeloplasty can recover a significant part of lost renal function. However, most of these patients do not achieve normal postoperative renal function.

Clues for the early loss of renal function in congenital hydronephrosis: Analysis of renal pelvis collagen ratio, diuresis renography and upper urinary tract morphology

INTRODUCTION

Diagnosing real urinary obstruction and surgical decision making for the operative correction of urinary obstruction, are still problematic in congenital hydronephrosis (CH). Compliance of the renal pelvis is one of the important defense mechanisms of renal parenchyma against urinary obstruction. We observed early loss of function in some cases of CH with low and moderate anteroposterior diameter of the renal pelvis (APDRP).

OBJECTIVE

To evaluate structural properties of the renal pelvic tissue of patients with CH and the relation of these structural properties with renal function and Anteroposterior diameter of the renal pelvis.

STUDY DESIGN

Ureteropelvic junction (UPJ) excised during UPJ obstruction operations from 2013 to 2019 were evaluated histopathologically. The patients were divided into the two groups according to initial renal function, i.e. group with initial preoperative differential renal function (DRF) less than 35% and group with initial DRF greater than 35%. The percentage of collagen to whole tissue area were analyzed using image processing program. The relationship between DRF and tissue collagen ratio, SFU and APDRP was evaluated.

RESULTS

There were 5 patients in the DRF <35% group and 16 patients in the DRF >35% group. However, APDRP's of the DRF <35% group were also significantly lower than the DRF >35% group. The collagen distribution in the muscle layer was more prominent in the DRF <35% group. Proportionally, percentage of collagen stained surface was significantly higher in DRF <35% group.

DISCUSSION

There are numerous histopathological studies evaluating the cause of UPJ obstruction. Besides these studies that are oriented to etiology, there are many studies comparing the histopathological changes at UPJ with surgical outcome and prognosis. In the present study, we found that renal pelvis collagen ratio was significantly increased in patients with lower APDRP and with severe renal function loss. This increase in the collagen content in the renal pelvis have been shown to affect the compliance negatively and decrease APDRP, which leads to a faster loss of renal function. Thus, pelvic structural changes accompanying UPJ obstruction may aggravate urinary obstructive process.

CONCLUSION

Increased renal pelvis collagen ratio negatively affects the expansion of the renal pelvis, which is one of the protective mechanisms of the renal parenchyma, and may be one of the triggering mechanisms of early loss of renal function.

Urinary biomarkers can identify the need for pyeloplasty in presence of supranormal differential renal function in antenatally diagnosed unilateral hydronephrosis

INTRODUCTION

Decision for surgery can be challenging in children with AH (Antenatal Hydronephrosis) especially in the setting of supranormal differential renal function (SnDRF).

OBJECTIVE

Aim of this study is to investigate whether IP-10 (interferon gamma-induced protein 10), MCP-1 (monocyte chemotactic protein-1), NGAL (neutrophil gelatinase-associated lipocalin), CA 19-9 (carbohydrate antigen 19-9), and KIM-1 (kidney injury molecule-1) can identify the need for pyeloplasty in presence of SnDRF in antenatally diagnosed unilateral hydronephrosis.

STUDY DESIGN

A prospectively collected urinary biomarker database was used for the study. There was a total of 53 patients in the AH group. Nineteen children with no history of AH and a normal urinary ultrasonography were taken as controls. Patients with initial ipsilateral DRF (Differential Renal Function) over 50% were included in the SnDRF group while the remaining were named as non-SnDRF. Patients that didn't undergo surgery were classified as non-obstructive dilation (NOD) in both groups.

RESULTS

Pyeloplasty was performed in 6/20 patients in SnDRF group, and in 19/33 patients in non-SnDRF group. Biomarker levels in the pyeloplasty and NOD groups were not affected by the presence or absence of SnDRF (p = 1.00, for both). Urinary NGAL, and CA 19-9 could determine the need for surgery in SnDRF group with 83% and 100% sensitivity, 86% and 79% specificity, respectively whereas urinary IP-10 and KIM-1 could with 84% and 83% sensitivity, 57% and 71% specificity, respectively. Urinary MCP-1 could differentiate patients who underwent surgery with 83% sensitivity and 50% specificity in SnDRF groups.

CONCLUSION

Our results showed that biomarker levels were not affected whether the kidney has SnDRF. Furthermore, in patients with SnDRF, NGAL and CA 19-9 appear to better estimate requirement for surgical correction before deterioration of renal function.

Symptomatology and Clinic of Hydronephrosis Associated With Uretero Pelvic Junction Anomalies

The most common cause of hydronephrosis in the pediatric age group is ureteropelvic junction-type hydronephrosis (UPJHN). Since the advent of widespread maternal ultrasound screening, clinical presentation of hydronephrosis associated with UPJ anomalies has changed dramatically. Today most cases are diagnosed in the prenatal period, and neonates present without signs or symptoms. For those who are not detected at birth, UPJHN eventually presents throughout childhood and even adulthood with various symptoms. Clinical picture of UPJHN highly depends on the presence and severity of obstruction, and whether it affects single or both kidneys. Abdominal or flank pain, abdominal mass, hematuria, kidney stones, urinary tract infections (UTI), and gastrointestinal discomfort are the main symptoms of UPJHN in childhood. Other less common findings in such patients are growth retardation, anemia, and hypertension. UTI is a relatively rare condition in UPJHN cases, but it may occur as pyelonephritis. Vesicoureteric reflux should be kept in mind as a concomitant pathology in pediatric UPJHN that develop febrile UTI. Although many UPJHN cases are known to improve over time, close clinical observation is critical in order to avoid irreversible kidney damage. The most appropriate approach is to follow-up the patients considering the presence of symptoms, the severity of hydronephrosis and the decrease in kidney function and, if necessary, to decide on early surgical intervention.

Grading of Hydronephrosis: An Ongoing Challenge

The crucial point for prompt diagnostics, ideal therapeutic approach, and follow-up of hydronephrosis associated with UPJ anomalies in children is the severity of hydronephrosis. Such many hydronephrosis grading systems as AP diameter, SFU, radiology, UTD, and Onen have been developed to evaluate hydronephrosis severity in infants. Unfortunately, it is still an ongoing challenge and there is no consensus between different disciplines. AP diameter is a very dynamic parameter and is affected by many factors (hydration, bladder filling, position, respiration). More importantly, its measurement is very variable and misleading due to different renal pelvic configurations. The radiology grading system has the same grades 1, 2, and 3 as the SFU grading system with addition of the AP diameter for the first 3 grades. This grading system divides parenchymal loss into two different grades. Grade 4 represents mild parenchymal loss while grade 5 suggests severe parenchymal loss. However, it is operator dependent, is not decisive, and does not differentiate grades 4 and 5 clearly. All grades of SFU are very variable between operators and clinicians. UTD classification aims to put all significant abnormal urinary findings together including the kidney, ureter, and bladder and thus determines the risk level for infants with any urinary disease. Different renal deterioration risks occur depending on the mechanism of hydronephrosis. Therefore, SFU and UTD classification may result in significant confusion and misleading in determining the severity of hydronephrosis. SFU-4 and UTD-P3 represent a considerable range of severity of hydronephrosis. Both represent minimal thinning of the medullary parenchyma and severe thinning of the cortical parenchyma (cyst-like hydronephrotic kidneys) at the same grade. The wide definition of SFU-4 and UTD-P3 fails to indicate accurately the severity of hydronephrosis and thus significantly misleads from a prompt treatment. They do not suggest who need surgical treatment and who can safely be followed non-operatively. The anatomy and physiology of the 4 suborgans of the kidney (renal pelvis, calices, medulla, and cortex) are completely different from each other. Therefore, each part of the kidney affect and behave differently as a response to UPJ-type hydronephrosis (UPJHN) depending on the severity of hydronephrosis. The upgraded Onen hydronephrosis grading system has been developed based on this basic evidence both for prenatal and post-natal periods. The Onen grading system determines specific detailed findings of significant renal damage, which clearly show and suggest who can safely be followed conservatively from who will need surgical intervention for UPJHN. Neither AP diameter nor radiology, SFU, or UTD classification is the gold standard in determining the severity of hydronephrosis. All these grading systems are based on subjective parameters and are affected by many factors. They do not determine the exact severity of UPJHN and thus cause permanent renal damage due to a delay in surgical decision in some infants while they may cause an unnecessary surgery in others. The Onen grading system has resolved all disadvantages of other grading systems and promises a safer follow-up and a prompt treatment for UPJHN. It is an accurate and easily reproducible grading that has high sensitivity and specificity.

Reliability of society of fetal urology and Onen grading system in fetal hydronephrosis

Objective

To evaluate the reliability of the Society for Fetal Urology (SFU) and Onen grading systems for fetal hydronephrosis in prenatal ultrasound according to the level of experience of the examiner.

Methods

We reviewed the prenatal ultrasound images of 146 fetuses (292 kidneys) that were diagnosed as having hydronephrosis between January 2005 and December 2014. One expert and two trainees assessed the prenatal renal ultrasound images using the SFU and Onen grading systems. The three examiners independently assessed each ultrasound image with both grading systems and reassessed the same images after 7 to 14 days. Cohen's kappa statistic was used to estimate intra- and inter-observer reliability in prenatal ultrasound images according to training level.

Results

The intra-observer reliability of the SFU grading system (κ 0.873–0.945) showed almost perfect agreement and that of the Onen grading system (κ 0.749–0.913) showed substantial to almost perfect agreement. The overall inter-observer reliability of the SFU grading system (κ 0.620–0.825) showed substantial to almost perfect agreement and that of the Onen grading system (κ 0.618–0.724) showed substantial agreement. The weighted kappa value of inter-observer agreement was 0.223 to 0.400 for SFU grade 1 and 0.064 to 0.346 for SFU grade 3. For Onen grading, the inter-observer agreement was 0.012 to 0.214 for grade 2 and 0.193 to 0.334 for grade 3.

Conclusion

Both the SFU and Onen grading systems showed good intra-observer agreement in prenatal ultrasonography. The inter-observer agreement was decreased in SFU grades 1 and 3 and Onen grades 2 and 3. Therefore, more focus should be given to SFU grades 1 and 3 and Onen grades 2 and 3 for trainees.

A long-term follow-up in conservative management of unilateral ureteropelvic junction obstruction with poor drainage and good renal function

The aim of the study was to retrospectively review the outcome of neonatal ureteropelvic junction obstruction with a good renal function and a poor drainage at a first diuretic renal scan, in cases where surgery was recommended on the basis of a loss of renal function, worsening of hydronephrosis or occurrence of clinical symptoms. Hydronephrosis was graded from 1 to 4 or as ureteral tract dilatation (UTD) P1 to UTD P3. During follow-up, 15 out of 38 patients (34.2%) required surgery while 25 out of 38 (65.8%) could have been managed conservatively. In patients with grade 2, 3, and 4 hydronephrosis, the ureteropelvic junction obstruction resolved or improved spontaneously in 100%, 63%, and 33% of cases (in 100% of UTD P1, 67% of UTD P2, and 50% of UTD P3), respectively. The median of follow-up was 14 years. Chi-square test showed a significant relationship between initial grade of hydronephrosis or UTD and the possibility of an efficient conservative management (p = 0.0088 and p = 0.0460).Conclusion: Conservative management can be safely achieved in ureteropelvic junction obstruction with poor drainage. Scheduled controls are needed for early discovery of functional renal deterioration. High-grade hydronephrosis is unlikely to resolve spontaneously and is often accompanied by a loss of renal function during the first years of life. What is Known: • There is controversy about which management should be adopted in infants with unilateral ureteropelvic junction obstruction with poor drainage but good differential renal function. What is New: • Long-term follow-up suggests that conservative management can be safely achieved also in unilateral ureteropelvic junction obstruction with poor drainage in more than 60% of cases, even if high-grade hydronephrosis is unlikely to resolve spontaneously and it is often accompanied by a loss of renal function during the first years of life. In our experience, surgical intervention was required in more than 50% of cases before 1 year of life and in all cases before 3 years of life.

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.

Effective predictors for surgical decision in antenatal hydronephrosis: a prospective multiparameter analysis

OBJECTIVE

The majority of antenatal hydronephrosis disappears spontaneously. In our study, we have investigated the effective predictors for surgical decision in antenatal hydronephrosis.

MATERIAL AND METHODS

Forty-four patients found to have renal pelvic anteroposterior (AP) diameter more than 10-mm on antenatal ultrasonograpy were followed after birth. The study groups were divided into two groups: follow-up and surgery group. On follow-up, longitudinal diameter of the kidney, parenchymal thickness of the kidney, AP diameter of renal pelvis, AP diameter of middle calyces on ultrasonograpy, and differential renal function, 20th minute clearance, half-life of radionuclide tracer (T1/2), Tmax, Tmax-T1/2, normalised residual activity (NORA) on diuretic renography were evaluated. Ultrasonograpy and diuretic renography measurements were compared in patients whose hydronephrosis resolve or proceeded to surgery.

RESULTS

Forty-four patients were diagnosed as antenatal hydronephrosis, spontaneous resolution occurred in 23 (52%), and surgery was performed in 21 patients (48%). Mean age at operation was 8.5±6.5 months (3-24 months). Mean AP diameter of renal pelvis was 29.5±14.2 mm for surgery group, 13.6±4.2 mm for follow-up group (p<0.001). Univariate analyses showed significance for all ultrasonographic measurements and only the differential renal function by diuretic renography. Multivariate logistic regression analysis showed significance for AP diameter of renal pelvis (odds ratio 1.37; 95% Cl 1.13-1.66), and differential renal function (odds ratio 1.14; 95% Cl 1.01-1.29).

CONCLUSION

AP diameter of renal pelvis and differential renal function were the most effective parameters for surgical decision. These parameters can be used for appropriate management of antenatal hydronephrosis.

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.

Therapeutic approaches and long-term follow-up for prenatal hydronephrosis

Objective:

This study summarises the outcomes of 149 patients who underwent surgery for antenatally diagnosed unilateral hydronephrosis.

Methods:

The medical records of such patients over a 23-year period were reviewed retrospectively. Age at the time of operation, preoperative and postoperative mean pelvic diameter on ultrasound, split renal function, washout patterns on scintigraphy, and early and late complications were recorded.

Results:

The mean preoperative follow-up period was five months (range: 1–66 months). One patient was operated on after 12 months and two patients after five years of follow-up. Mean preoperative pelvic diameter and renal function were 30.8 mm and 38.6%, respectively; all patients had an obstructive wash-out pattern. In the postoperative period, the corresponding measurements were 11.7 mm and 39.2%, with 111 non-obstructive, 24 partially obstructive, and 14 obstructive wash-out patterns. Three patients with severe caliectasis and low renal function underwent surgery despite mild hydronephrosis. The mean postoperative follow-up period was six (range 4–11) years. Complications developed in 14 (9.3%) patients.

Conclusion:

Patients with antenatal hydronephrosis may need surgery even after a follow-up period of six years. Because of the potential late development of complications, postoperative follow-up should be continued for 10 years.

Sonographic Renal Parenchymal Measurements for the Evaluation and Management of Ureteropelvic Junction Obstruction in Children

PURPOSE

To correlate sonographic renal parenchymal measurements among patients with ureteropelvic junction obstruction (UPJO) labeled society of fetal urology (SFU) hydronephrosis grades 1-4 and to examine whether sonographic renal parenchymal measurements could be used to differentiate conservative vs. surgical management.

MATERIALS AND METHODS

Retrospective chart review and sonographic renal parenchymal measurements (renal length, medullary pyramid thickness, and renal parenchymal thickness) were performed in patients with SFU grades 1-4 hydronephrosis secondary to UPJO managed between 2009 and 2014. Exclusion criteria included other concomitant genitourinary pathology or incomplete follow-up. Anterior-posterior renal pelvic diameter (APRPD) and radionuclide renography were also evaluated when available.

RESULTS

One hundred four patients with UPJO underwent 244 renal and bladder ultrasound (1,464 sonographic renal parenchymal measurements in 488 kidneys). Medullary pyramid thickness and renal parenchymal thickness progressively decreased from SFU grades 1-4 (p < 0.05). A similar trend was appreciated when comparing SFU grades 1 and 2 vs. 3 and 4, as well as SFU grades 3 vs. 4 (p < 0.05). SFU grade 3 and 4 patients who underwent pyeloplasty had longer renal length in comparison to those who were managed conservatively (p < 0.02).

CONCLUSION

This is the first study that evaluates these objective, quantifiable sonographic renal parenchymal measurements in children with unilateral UPJO. These sonographic renal parenchymal measurements correlate closely with worsening of hydronephrosis graded by the SFU and APRPD classification systems. Prospective studies are needed to elucidate the role of sonographic renal parenchymal measurements in the management of children with UPJO.

Comparison of the reliability of two hydronephrosis grading systems: the Society for Foetal Urology grading system vs. the Onen grading system

AIM

To compare the reliability of the conventional ultrasonography grading system for hydronephrosis as suggested by the Society for Fetal Urology (SFU) in 1993 and that developed by Onen in 2007.

MATERIALS AND METHODS

One hundred and eighty kidneys in 90 paediatric patients were assessed by four radiologists using each of the two grading systems twice. The SFU system was graded 0-4 (0 = no hydronephrosis; 1 = visualized only renal pelvis; 2 = plus a few caliceal dilatation; 3 = all calyceal dilatation; 4 = plus parenchymal thinning). The Onen system was graded 0-4 (0 = no hydronephrosis; 1 = only renal pelvic dilatation; 2 = plus caliceal dilatation; 3 = plus <50% renal parenchymal loss; 4 = plus >50% renal parenchymal loss). Cohen's kappa statistic was used to estimate intra- and interobserver agreement. The weighted least-squares approach was used to compare the intra-observer agreement, and bootstrapping was used to compare the interobserver agreement between the two systems.

RESULTS

Intra-observer agreement was substantial to almost perfect in both the SFU (κ 0.79-0.95) and the Onen (κ 0.66-0.97) grading system without difference. The overall interobserver agreement was substantial in both the SFU (κ 0.61-0.68) and the Onen (κ 0.66-0.76) grading system. However, interobserver agreement was fair to moderate for SFU grades 1 and 2 and Onen grades 2 and 3.

CONCLUSION

Both the SFU and Onen grading system are reliable with good intra- and interobserver agreement. However, decreased interobserver agreement was demonstrated for SFU grades 1 and 2 and Onen grades 2 and 3.

Interference of mobile phones and digitally enhanced cordless telecommunications mobile phones in renal scintigraphy

PURPOSE

The aim of the study was to assess the potential negative impact of cellular phones and digitally enhanced cordless telecommunication (DECT) devices on the quality of static and dynamic scintigraphy to avoid repeated testing in infant and teenage patients to protect them from unnecessary radiation exposure.

METHODS

The assessment was conducted by performing phantom measurements under real conditions. A functional renal-phantom acting as a pair of kidneys in dynamic scans was created. Data were collected using the setup of cellular phones and DECT phones placed in different positions in relation to a camera head to test the potential interference of cellular phones and DECT phones with the cameras.

RESULTS

Cellular phones reproducibly interfered with the oldest type of gamma camera, which, because of its single-head specification, is the device most often used for renal examinations. Curves indicating the renal function were considerably disrupted; cellular phones as well as DECT phones showed a disturbance concerning static acquisition.

CONCLUSIONS

Variable electromagnetic tolerance in different types of γ-cameras could be identified. Moreover, a straightforward, low-cost method of testing the susceptibility of equipment to interference caused by cellular phones and DECT phones was generated. Even though some departments use newer models of γ-cameras, which are less susceptible to electromagnetic interference, we recommend testing examination rooms to avoid any interference caused by cellular phones. The potential electromagnetic interference should be taken into account when the purchase of new sensitive medical equipment is being considered, not least because the technology of mobile communication is developing fast, which also means that different standards of wave bands will be issued in the future.

Postnatal evaluation of intrauterine hydronephrosis due to ureteropelvic junction obstruction

PURPOSE: Fetal hydronephrosis is a frequent finding due to advances in prenatal ultrasonography. The definition of fetal and neonatal urinary tract obstruction is a very difficult task requiring confirmation of reduced renal function and hydronephrosis. In this study we followed a series of consecutive patients with intrauterine hydronephrosis that persisted during post-natal life. METHODS: 116 newborns with antenatal hydronephrosis diagnosed by ultrasound and submitted to a specific post-natal evaluative protocol with a follow-up period of 6 years. RESULTS: In 45 (38.8%) of 116 patients, ureteropelvic junction (UPJ) obstruction was confirmed and surgical correction of the UPJ obstruction was done in 19 patients. From 26 children who were initially submitted to non-surgical treatment, only 6 (23%) needed a surgical approach during follow up. Overall analysis showed that surgery was performed in 25 patients with UPJ obstruction, and the others 20 patients were kept under clinical observation, since normal renal function was confirmed by scintigraphy scans. CONCLUSION: Fetal hydronephrosis due to UPJ obstruction deserves careful postnatal evaluation. UPJ obstruction is the most frequent anomaly and its surgical treatment has very precise indications. The evaluative protocol was useful in identify patients that could be followed-up with a non-surgical approach.

Pelvis/cortex ratio: A sonographic marker of pelvi ureteric junction obstruction in children

Objectives

The aim of the study is to document pelvis/cortex ratio (P/C ratio) in children presenting with antenatally detected hydronephrosis and determine whether it could be used as a sonographic marker of Pelvi ureteric junction (PUJ) obstruction.

Materials and Methods:

All the children presenting with unilateral fetal hydronephrosis (PUJ) between Jan 2007 and March 2008 were included. Ultrasonogram was performed by the same sonologist and P/C ratio was determined by dividing maximum anteroposterior pelvic diameter with maximum cortical thickness.

Results:

Among a total of 111 children, 87 (78%) improved on conservative management while 24 (22%) required pyeloplasty. The mean (± SD) P/C ratio was 2.7 ± 2.18 in those improved on conservative management while 13.5 ± 1.48 in those who required surgery (P < 0.01). All (22/22) children with P/C ratio of 12 or above required pyeloplasty, while 2/5 with P/C ratio 8-12 and none (0/84) with P/C ratio less than 8 required pyeloplasty (P<0.01).

Conclusions:

P/C ratio could be used as a marker of PUJ obstruction in children with hydronephrosis.

[Hydronephrosis: urgency of interventions and recommended times for surgical correction]

The prevalence of malformations of the kidneys is quite high compared to other congenital malformations. In a study of the Association for Neonatology of Mecklenburg-West Pomerania examining 37,634 births, a hydronephrotic kidney was diagnosed in 16.7 of 10,000 children. Depending on the type and severity of the congenital malformation it might be difficult to find out when there is a risk for loss of renal function. Unfortunately, in 2010 health politicians (the Gemeinsame Bundesausschuss) voted against routine ultrasound screening for renal abnormalities in newborns despite an increasing number of pre- or postnatally diagnosed dilated kidneys in recent years. Will this lead to a decrease in the diagnosis of hydronephrosis with possible loss of renal function later on? According to Roth et al. the incidence of in utero dilatations of the urinary tract is about 1:100, but only 1:500 children have a clinically relevant problem. This raises the question of which of these young patients need an intervention and which might be monitored expectantly.