An overview of the literature on congenital lower urinary tract obstruction and introduction to the PLUTO trial: Percutaneous shunting in lower urinary tract obstruction

Predictors of advanced chronic kidney disease in infancy after definitive vesicoamniotic shunting for congenital lower urinary tract obstruction

BACKGROUND

Severe congenital lower urinary tract obstruction (cLUTO) is associated with poor postnatal outcomes, including chronic and end stage kidney disease, and high mortality. Studies of the impact of fetal intervention through vesicoamniotic shunting are marred by a device malfunction rate of up to 60%. In this study, we delineate the postnatal course and infant kidney function following definitive urinary diversion in utero.

MATERIALS AND METHODS

This is a retrospective, single-center cohort study of 16 male infants who survived the fetal intervention to birth, from 2010 to 2014 at a single center. All had patent shunts in place at birth. Perinatal and biochemical characteristics were collected with patients followed for one year, or until demise, with serial measures of serum creatinine (SCr) and serum cystatin C (CysC).

RESULTS

Of the 16 males, 81% were non-white (38% black, 43% Hispanic). Shunts were placed at a median of 20 weeks (IQR 19,23) gestation, with median fetal bladder volume of 39 cm³ (IQR 9.9,65). All neonates were born preterm [median 34 weeks (IQR 31,35)] and the majority with low birth weight [median 2340 grams (1,895, 2,600)]. 63% required positive pressure ventilation. Advanced chronic kidney disease stage 4-5 at 1 year of age was predicted by neonatal characteristics: peak SCr ≥2 mg/dl, time to peak SCr > 6 days, discharge SCr ≥1.0 mg/dl, CysC ≥2.5 mg/l, urine protein:creatinine ≥4.8 mg/mg, urine microalbumin:creatinine ≥2.2 mg/mg. In infancy, a nadir SCr ≥0.5 mg/dl occurring before 160 days (5.3 months) of age was also predictive of advanced chronic kidney disease stage 4-5 at 1 year. Three patients died in the neonatal period, with 1 receiving kidney replacement therapy (KRT). Three additional patients required KRT before 12 months of age.

CONCLUSIONS

Even with definitive vesicoamniotic shunting for cLUTO, postnatal morbidity and mortality remain high, emphasizing the role of renal dysplasia, in spite of urinary diversion, in postnatal kidney dysfunction. Neonatal and infant biochemical parameters exhibit distinct trends that offer families and physicians a better understanding of the prognosis of childhood kidney function.

Z-scores of fetal bladder size for antenatal differential diagnosis between posterior urethral valves and urethral atresia

OBJECTIVE

To construct reference values for fetal urinary bladder distension in pregnancy and use Z-scores as a diagnostic tool to differentiate posterior urethral valves (PUV) from urethral atresia (UA).

METHODS

This was a prospective cross-sectional study in healthy singleton pregnancies aimed at constructing nomograms of fetal urinary bladder diameter and volume between 15 and 35 weeks' gestation. Z-scores of longitudinal bladder diameter (LBD) were calculated and validated in a cohort of fetuses with megacystis with ascertained postnatal or postmortem diagnosis, collected from a retrospective, multicenter study. Correlations between anatomopathological findings, based on medical examination of the infant or postmortem examination, and fetal megacystis were established. The accuracy of the Z-scores was evaluated by receiver-operating-characteristics (ROC)-curve analysis.

RESULTS

Nomograms of fetal urinary bladder diameter and volume were produced from three-dimensional ultrasound volumes in 225 pregnant women between 15 and 35 weeks of gestation. A total of 1238 urinary bladder measurements were obtained. Z-scores, derived from the fetal nomograms, were calculated in 106 cases with suspected lower urinary tract obstruction (LUTO), including 76 (72%) cases with PUV, 22 (21%) cases with UA, four (4%) cases with urethral stenosis and four (4%) cases with megacystis-microcolon-intestinal hypoperistalsis syndrome. Fetuses with PUV showed a significantly lower LBD Z-score compared to those with UA (3.95 vs 8.83, P < 0.01). On ROC-curve analysis, we identified 5.2 as the optimal Z-score cut-off to differentiate fetuses with PUV from the rest of the study population (area under the curve, 0.84 (95% CI, 0.748-0.936); P < 0.01; sensitivity, 74%; specificity, 86%).

CONCLUSIONS

Z-scores of LBD can distinguish reliably fetuses with LUTO caused by PUV from those with other subtypes of LUTO, with an optimal cut-off of 5.2. This information should be useful for prenatal counseling and management of LUTO. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Prediction model of postnatal renal function in fetuses with lower urinary tract obstruction (LUTO)-Development and internal validation

OBJECTIVE

To develop a prediction model of postnatal renal function in fetuses with lower urinary tract obstruction (LUTO) based on fetal ultrasound parameters and amniotic fluid volume.

METHODS

Retrospective nationwide cohort study of fetuses with postnatally confirmed LUTO and known eGFR. Fetuses treated with fetal interventions such as vesico-amniotic shunting or cystoscopy were excluded. Logistic regression analysis was used to identify prognostic ultrasound variables with respect to renal outcome following multiple imputation of missing data. On the basis of these fetal renal parameters and amniotic fluid volume, a model was developed to predict postnatal renal function in fetuses with LUTO. The main study outcome was an eGFR less than 60 mL/min * 1.73 m² based on the creatinine nadir during the first year following diagnosis. Model performance was evaluated by receiver operator characteristic (ROC) curve analysis, calibration plots, and bootstrapping.

RESULTS

Hundred one fetuses with a confirmed diagnosis of LUTO were included, eGFR less than 60 was observed in 40 (39.6%) of them. Variables predicting an eGFR less than 60 mL/min * 1.73m² included the following sonographic parameters: hyperechogenicity of the renal cortex and abnormal amniotic fluid volume. The model showed fair discrimination, with an area under the ROC curve of 0.70 (95% confidence interval, 0.59-0.81, 0.66 after bootstrapping) and was overall well-calibrated.

CONCLUSION

This study shows that a prediction model incorporating ultrasound parameters such as cortical appearance and abnormal amniotic fluid volume can fairly discriminate an eGFR above or below 60 mL/min * 1.73m² . This clinical information can be used in identifying fetuses eligible for prenatal interventions and improve counseling of parents.

Current strategies to predict and manage sequelae of posterior urethral valves in children

Posterior urethral valves (PUV) constitute a significant urological cause of chronic kidney disease (CKD) in children. The condition is characterised by the unique pathophysiology of the evolution of bladder dysfunction after relief of obstruction, which contributes to CKD. Improvements in prenatal diagnosis followed by selective foetal intervention have not yet produced improvement in long-term renal outcomes, although better patient selection may alter this in the future. Proactive management with surveillance, pharmacotherapy, timed voiding, double voiding, and/or assisted bladder-emptying, is being increasingly offered to those with severe bladder dysfunction and has the potential of reducing the burden of renal disease. Clinicians are currently able to counsel regarding the prognosis using serum creatinine and other emerging markers. However, much of this work remains to be validated. Satisfactory graft survival rates are now reported with aggressive management of bladder dysfunction in children who are candidates for renal transplantation. Knowledge gaps exist in identifying early markers of renal injury, risk stratification, and in understanding patient and carer perspectives in PUV.

Sequential fetal serum β2-microglobulin to predict postnatal renal function in bilateral or low urinary tract obstruction

OBJECTIVE

Fetal serum β2-microglobulin has been shown to predict postnatal renal outcome in cases of fetal obstructive uropathy. We assessed the value of serial measurements of fetal serum β2-microglobulin in the prediction of postnatal renal outcome.

METHODS

We retrospectively studied renal outcome in 42 fetuses with bilateral or low urinary tract obstruction that had fetal blood sampling on at least two occasions to assay serum levels of β2-microglobulin. Amniotic fluid volume at the time of each sampling was recorded. We classified renal outcome as either favorable (when postnatal renal function was normal) or adverse (when postnatal chronic renal failure occurred or when renal dysplasia at autopsy was noted). A β2-microglobulin cut-off of 5 mg/L and amniotic fluid index of 5 cm were used to predict postnatal renal outcome.

RESULTS

Renal outcome was adverse in 28 cases and favorable in 14. In 12 (28.6%) cases, fetal serum β2-microglobulin concentration differed between the first and last measurement. Prediction of postnatal renal outcome was correct in 11 of these cases based on the last β2-microglobulin measurement. The sensitivity of β2-microglobulin in predicting renal outcome was significantly higher (P = 0.005) when using the last rather than the first measurement (96.4% vs 64.3%), with similar specificity for both measurements (85.7% vs 78.6%, non-significant). The sensitivity of amniotic fluid volume was also significantly higher (P = 0.005) when using the last rather than the first measurement (75.0% vs 35.7%), with similar specificity for both measurements (64.3% vs 71.4%, non-significant).

CONCLUSION

Sequential measurement of serum β2-microglobulin, performed for adverse ultrasound findings, such as renal parenchymal abnormality or decreasing amniotic fluid volume, predicts postnatal renal outcome more accurately than does a single assay. This may be due to possible worsening of renal injury with increasing duration of urinary tract obstruction. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Antenatal Determinants of Long-Term Kidney Outcome in Boys with Posterior Urethral Valves

Background: Posterior urethral valves (PUV) are the most important cause of end-stage renal disease (ESRD) in young boys. The objective of this report was to define the antenatal determinants of long-term postnatal renal outcome in this condition. Design: This was a retrospective cohort analysis. The primary outcome was the development of ESRD defined as starting dialysis or receiving a preemptive kidney transplant. Results: Eighty-two cases of PUV were identified, with 17 (21%) developing ESRD at 6.1 ± 7.1 years. Cases developing ESRD were more likely diagnosed antenatally (41 vs. 19%, p = 0.05), had a younger gestational age (35.5 ± 3.4 weeks vs. 37.3 ± 2.1 weeks, p = 0.02), and on antenatal ultrasound scan were more likely to have oligohydramnios (60 vs. 26%, p = 0.02), renal cortical cysts (47 vs. 17%, p = 0.02), and the combination of oligohydramnios, renal cortical cysts, and increased renal echogenicity (47 vs. 9%, p = 0.002). Conclusions: In boys with PUV, decreased gestational age, oligohydramnios, renal cysts, and the combination of oligohydramnios, cortical cysts, and echogenic kidneys were associated with ESRD, while the combination was an independent predictor of poor long-term postnatal kidney function.

Fetal intervention for severe lower urinary tract obstruction: a multicenter case-control study comparing fetal cystoscopy with vesicoamniotic shunting

OBJECTIVE

To evaluate the efficacy of fetal intervention using fetal cystoscopy or vesicoamniotic shunting in the treatment of severe lower urinary obstruction (LUTO).

METHODS

A cohort of 111 fetuses with severe LUTO attending two centers between January 1990 and August 2013 were included retrospectively. Fetuses were categorized into three groups based on the method of intervention: (1) fetal cystoscopy, (2) vesicoamniotic shunting or (3) no intervention. Multivariate analyses were performed to determine the probability of survival and normal renal function until 6 months of age by comparing fetal cystoscopy and vesicoamniotic shunting to no fetal intervention.

RESULTS

Of the 111 fetuses with severe LUTO that were included in the analysis, fetal cystoscopy was performed in 34, vesicoamniotic shunting was performed in 16 and there was no fetal intervention in 61. Gestational age at diagnosis, method of fetal intervention and cause of bladder obstruction were associated with prognosis. In multivariate analysis and after adjustment for potential confounders (considering all causes of LUTO) the overall probability of survival was significantly higher with fetal cystoscopy and vesicoamniotic shunting when compared to no intervention (adjusted relative risk (ARR), 1.86 (95% CI, 1.01-3.42; P = 0.048) and ARR, 1.73 (95% CI, 1.01-3.08; P = 0.04) respectively). A clear trend for normal renal function was present in the fetal cystoscopy group (ARR, 1.73 (95% CI, 0.97-3.08; P = 0.06)) but was not observed in the vesicoamniotic shunt group (ARR, 1.16 (95% CI, 0.86-1.55; P = 0.33)). In cases in which there was a postnatal diagnosis of posterior urethral valves, fetal cystoscopy was effective in improving both the 6-month survival rate and renal function (ARR, 4.10 (95% CI, 1.75-9.62; P < 0.01) and 2.66 (95% CI, 1.25-5.70; P = 0.01) respectively) while vesicoamniotic shunting was associated only with an improvement in the 6-month survival rate (ARR, 3.76 (95% CI, 1.42-9.97; P < 0.01)) with no effect on renal function (ARR, 1.03 (95% CI, 0.49-2.17, P = 0.93)).

CONCLUSION

Fetal cystoscopy and vesicoamniotic shunting improve the 6-month survival rate in cases of severe LUTO. However, only fetal cystoscopy may prevent impairment of renal function in fetuses with posterior urethral valves. Our data support the idea of performing a subsequent randomized controlled trial to compare the effectiveness of fetal cystoscopy vs vesicoamniotic shunting for severe fetal LUTO.

Fetal surgery: principles, indications, and evidence

Since the first human fetal surgery was reported in 1965, several different fetal surgical procedures have been developed and perfected, resulting in significantly improved outcomes for many fetuses. The currently accepted list of fetal conditions for which antenatal surgery is considered include lower urinary tract obstruction, twin-twin transfusion syndrome, myelomeningocele, congenital diaphragmatic hernia, neck masses occluding the trachea, and tumors such as congenital cystic adenomatoid malformation or sacrococcygeal teratoma when associated with developing fetal hydrops. Until recently, it has been difficult to determine the true benefits of several fetal surgeries because outcomes were reported as uncontrolled case series. However, several prospective randomized trials have been attempted and others are ongoing, supporting a more evidence-based approach to antenatal intervention. Problems that have yet to be completely overcome include the inability to identify ideal fetal candidates for antenatal intervention, to determine the optimal timing of intervention, and to prevent preterm birth after fetal surgery. Confronting a fetal abnormality raises unique and complex issues for the family. For this reason, in addition to a maternal-fetal medicine specialist experienced in prenatal diagnosis, a pediatric surgeon, an experienced operating room team including a knowledgeable anesthesiologist, and a neonatologist, the family considering fetal surgery should have access to psychosocial support and a bioethicist.

Urological fistulas after fetal cystoscopic laser ablation of posterior urethral valves: surgical technical aspects

OBJECTIVE

To describe the surgical technical aspects associated with the development of urological fistulas after fetal antegrade cystoscopic laser fulguration of the posterior urethral valves (PUV).

METHODS

The perioperative data for all fetal cystoscopies performed between January 2004 and August 2013 at three institutions in the USA, France and Brazil were reviewed, with particular emphasis on surgical technical aspects of the procedure and the complications encountered.

RESULTS

A total of 40 fetal cystoscopies were performed at the three institutions. Laser fulguration of the PUV was performed in 23 of these cases, with a survival rate of 60.9% (14/23) and normal renal function in 85.7% (12/14) of these infants. Urological fistulas were diagnosed postnatally in four (10%) newborns. The presence of fistulas was associated with a higher gestational age at diagnosis of PUV (P < 0.01) and with the use of semi-curved rather than curved sheaths (P < 0.01), the use of a diode laser (P < 0.01) and the use of higher laser power and energy (P < 0.01 and P < 0.01, respectively), as well as with less operator experience (P < 0.01) and with absence of fetal anesthesia/immobilization (P = 0.02).

CONCLUSION

Urological fistulas are a severe complication of fetal cystoscopic laser fulguration of PUV and are associated with type, energy and power settings of the laser and instrumentation. The use of appropriate technique and proper training of the operator are necessary to perform this fetal intervention safely.

Fetal posterior urethral valve mechanic perforation using an 18-gauge needle: a case-series

Objective: To assess the effectiveness of using an 18-gauge needle inserted through the perineal surface of the fetus to solve magacystis and posterior urethral valve (PUV).

Methods: From February 2008 to January 2012, 15 cases of magacystis were referred to our tertiary referral center, and in ten, PUV was suspected. In the cases where PUV was suspected after a detailed ultrasound scan, women gave consent to proceed with fetal therapy under sonographic guidance using an 18-gauge needle. The procedures lasted for a median time of 30 min (range 15–50 min). The needle was inserted through the perineal surface of the fetus to perforate the dilated posterior ureteral valve, as well as to perform a perineal vescicocentesis.

Results: Median gestational age at time of referral was 17 weeks of gestation (range 16–19 weeks). Five fetuses were female and ten male. Nine cases opted for pregnancy termination, as the kidneys were dysplastic showing hyperechoic structure, while six cases were treated, as the kidneys showed a normal functionality as well as cortico-medullar differentiation. Five fetuses were male and one female. After fetal therapy, there were no stillbirths. All fetuses were delivered at term and the infants were followed up by routine kidney ultrasonography and functionality after a median follow-up of 16 months.

Conclusions: Despite the most commonly used fetal therapy being vesico-amiotic shunting, percutaneous fetal cystoscopy that allows laser valve ablation and mechanical disruption was the procedure used in the present study. This allowed the direct treatment of the urethral obstruction that caused megacystis, without need to repeat the procedure and without the need of any postnatal therapy.

Evaluation of the cost effectiveness of vesico-amniotic shunting in the management of congenital lower urinary tract obstruction (based on data from the PLUTO Trial)

Objective

To determine the cost-effectiveness of in-utero percutaneous Vesico Amniotic Shunt (VAS) in the management of fetal lower urinary tract obstruction (LUTO)

Design

Model based economic analysis using data from the randomised controlled arm of the PLUTO (percutaneous vesico-amniotic shunting for lower urinary tract obstruction) trial.

Setting

Fetal medicine departments in United Kingdom, Ireland and Netherlands.

Population or Sample

Pregnant women with a male, singleton fetus with LUTO.

Methods

Costs and outcomes were prospectively collected in the trial; three separate base case analyses were performed using the intention to treat (ITT), per protocol and uniform prior methods. Deterministic and probabilistic sensitivity analyses were performed to explore data uncertainty.

Main Outcome Measures

Survival at 28 days, 1 year and disease free survival at 1 year.

Results

VAS was more expensive but appeared to result in higher rates of survival compared with conservative management in patients with LUTO. Using ITT analysis the incremental cost effectiveness ratios based on outcomes of survival at 28 days, 1 year, or 1 morbidity-free year on the VAS arm were £15,506, £15,545, and £43,932, respectively.

Conclusions

VAS is a more expensive option compared to the conservative approach in the management of individuals with LUTO. Data from the RCT suggest that VAS improves neonatal survival but does not result in significant improvements in morbidity. Our analysis concludes that VAS is not likely to be cost effective in the management of these patients given the NICE (National Institute of Health and Clinical Excellence) cost threshold of £20,000 per QALY.

Intrauterine surgery--choices and limitations

BACKGROUND

The past decade has seen much progress in intrauterine surgery. Randomized trials have documented the benefit of some procedures of this type for the unborn child.

METHOD

Selective literature review

RESULTS

Randomized trials have demonstrated the benefit of fetoscopic laser coagulation of placental anastomoses in twin-to-twin transfusion syndrome (TTTS) and of intrauterine surgery via hysterotomy for the repair of spina bifida. Other fetoscopic procedures have yielded promising initial results but are not yet supported by findings from randomized trials. Some intrauterine surgical procedures must still be considered experimental in view of the lack of randomized trials and the rarity of the conditions they are designed to treat. Fetoscopic laser coagulation for TTTS is by far the most common procedure in fetal surgery; TTTS arises in roughly 1 in 2500 pregnancies. The other procedures discussed in this article are performed much less often and for rarer indications. In general, intrauterine surgery is indicated only to treat conditions that would otherwise lead to intrauterine death or irreversible prenatal damage.

CONCLUSION

Intrauterine surgery is a rapidly developing field. Prenatal intervention by laser coagulation is indicated to treat severe TTTS, as its benefit has been shown in a randomized trial. Not enough evidence is yet available for the possible benefit of intrauterine surgery to treat myelomeningocele and congenital diaphragmatic hernia. Other indications are experimental. When an indication for intrauterine surgery exists, the parents should be informed and, depending on their wishes, referred to a center where it can be performed.

Neonatal ascites and oligohydramnios: the role of kidney

Posterior urethral valve pathologies are the most frequent childhood obstructive uropathy reported, and we infer their presence on diagnosing foetal ascites and oligohydramnios. Early action is vital to determine the long-term development and the degree of impairment of renal function. We report a newborn male 34 weeks of gestation with a prenatal diagnosis of foetal ascites, fluid on the loose in renal fossa and oligohydramnios. Subsequent studies have shown the presence of posterior urethral valves with associated significant vesicoureteral reflux. There was no secondary renal damage. Intrauterine decompression of the urinary tract seems to have exerted a protective role against kidney damage. This finding supports the role of foetal decompression surgery in early and severely obstructive forms to improve the prognosis of renal function in the long term.

Prune belly syndrome

The majority of paediatric surgeons will encounter a patient with prune belly syndrome (PBS) only a few times in their clinical practice. There have been many opposing views in the literature regarding the pathogenesis and management of this complex condition. A detailed review was conducted using PubMed to identify key publications involving PBS. This article discusses the evolution of our understanding of the pathogenesis and diagnosis of PBS, including its typical characteristics. We describe the management options available for bilateral intra-abdominal testes, the deficient abdominal wall, the dilated urinary system and examine the evidence base used to support the current approaches employed.

Current perspectives on congenital obstructive nephropathy

Congenital obstructive nephropathy is the leading cause of chronic renal disease in children. As a result, it represents a tremendous societal burden in terms of morbidity and mortality, as well as in health care expenses of caring for children with chronic kidney disease and end-stage renal disease. The various diagnostic, prognostic, and therapeutic challenges associated with congenital obstructive nephropathy highlight the importance of developing effective experimental models for studying this disease process. In this review, we define the clinical entity that is congenital obstructive nephropathy, outline the current standards of diagnosis and care, and discuss the utilization of current experimental models designed to help clarify some of the clinical conundrums associated with this important disease.

Posterior urethral valves: renal failure and prenatal treatment

Posterior urethral valves occur in 1 : 5000 live births. Despite the high prevalence, the few children that survive do poorly, with over 50% progressing to ESRD in 10 years. The gold standard for post-natal diagnosis is voiding cystourethrography, while pre-natal diagnosis is dependent on routine screening ultrasonography. Despite the ability to identify features of bladder outlet obstruction early in fetal development, there is no consensus on how to incorporate early detection into current screening protocols. There has yet to be a marker that allows prediction of obstruction in the absence of or prior to radiographic evidence of obstruction. With our current screening strategy, the majority of interventions are performed well after irreversible damage has occurred. Improved mortality and long term morbidity from posterior urethral valves and congenital bladder outlet obstruction will likely remain unchanged until it is possible to intervene prior to the onset of irreversible renal damage. New biologic markers and improved instrumentation will allow for more effective diagnosis and intervention at earlier stages of fetal development.

Fetal therapy: practical ethical considerations

Progress in prenatal diagnosis can lead to the diagnosis of severe fetal abnormalities for which natural history anticipates a fatal outcome or the development of severe disability despite optimal postnatal care. Intrauterine therapy can be offered in these selected cases. Prenatal diagnosis is the only field of medicine in which termination is an option in the management of severe diseases. Fetal therapy has therefore developed as an alternative to fatalist expectant prenatal management as well as to termination of pregnancy (TOP). There are few standards of fetal care that have gone beyond the stage of equipoise and even fewer have been established based on appropriate studies comparing pre- and postnatal care. Several ethical questions are being raised as fetal surgery develops, including basic Hippocratic principles of patients' autonomy and doctors' duty of competence moving the boundaries between experimental surgery, therapeutic innovation and standard care. In addition, the technical success of a fetal intervention can only rarely fully predict the postnatal outcome. Managing uncertainty regarding long-term morbidity and the possibility for fetal therapy to change the risk of perinatal death into that of severe handicap remains a critical factor affecting women's choice for TOP as an alternative to fetal therapy.

Effectiveness of fetal cystoscopy as a diagnostic and therapeutic intervention for lower urinary tract obstruction: a systematic review

OBJECTIVE

To determine the effectiveness of fetal cystoscopy in the prenatal diagnosis of and intervention for congenital lower urinary tract obstruction.

METHODS

This study was a literature search using MEDLINE, Embase, Cochrane Library, MEDION, Web of Science reference lists and contact with experts. All studies reporting on fetal cystoscopy in lower urinary tract obstruction with data for a 2 × 2 table were selected for review. No language restrictions were applied. There was independent selection of studies, data extraction and quality assessment by two reviewers. Peto odds ratios were calculated as a summary measure of effect.

RESULTS

A total of 2071 citations were identified and 66 papers selected for detailed evaluation, from which four papers with a total of 63 patients were selected for inclusion. Two papers had results for the use of cystoscopy in diagnosis, showing that fetal cystoscopy altered the ultrasound diagnosis of the underlying pathology in 36.4 and 25.0% of fetuses, respectively. Compared to no treatment, fetal cystoscopic intervention demonstrated an odds ratio for improved perinatal survival of 20.51 (95% CI, 3.87-108.69). However, comparing vesicoamniotic shunt (VAS) with fetal cystoscopy there appeared to be no significant improvement in the perinatal survival odds ratio of 1.49 (95% CI, 0.13-16.97). These results had wide CIs and for cystoscopy vs. VAS, all results crossed the line of no effect.

CONCLUSION

There is little published evidence for the effectiveness of therapeutic fetal cystoscopy as an intervention for congenital lower urinary tract obstruction and the quality of this evidence is poor. It should thus be considered to be an 'experimental intervention' and subjected to further investigation.

New and/or improved aspects of fetal surgery

Open fetal surgery through a wide hysterotomy is no longer a real option for prenatal intervention, but a minimally invasive approach has emerged as treatment for a small number of indications. Endoscopic ablation of placental vessels is the preferred treatment for severe twin-to-twin transfusion syndrome and it may be the only chance to salvage the most severe forms of congenital diaphragmatic hernia. Several other indications are currently under review and may become justified in the future, provided that diagnostic accuracy and patient selection become more accurate. Before invasive fetal intervention becomes widely accepted, however, we need to better define outcome. It is no longer acceptable to express results in terms of survival at birth. Survival at discharge and long-term morbidity must be considered as well.

The Society for Fetal Urology consensus statement on the evaluation and management of antenatal hydronephrosis

The evaluation and management of fetuses/children with antenatal hydronephrosis (ANH) poses a significant dilemma for the practitioner. Which patients require evaluation, intervention or observation? Though the literature is quite extensive, it is plagued with bias and conflicting data, creating much confusion as to the optimal care of patients with ANH. In this article, we summarized the literature and proposed recommendations for the evaluation and management of ANH.

CONGENITAL URINARY BLADDER OUTLET OBSTRUCTION

The term congenital ‘bladder outlet obstruction (BOO)’ describes the collection of conditions in which the normal, urethral egress of urine from the fetal bladder is impaired. The term is interchangeable with fetal ‘lower urinary tract obstruction’, as used by other authors. After considering normal urinary tract embryology, we describe the epidemiology of congenital BOO and the primary anatomical disorders associated with it. We then proceed to describe its fetal and postnatal clinical manifestations and then consider therapies and interventions which have been used to manage the condition. We not only focus on urethral and bladder disease with constitutes BOO itself, but also describe associated kidney disorders which, via chronic renal excretory failure, are important causes of morbidity. Rather than provide an exhaustive review, we emphasise studies published in the last decade, and therefore readers are referred to other reviews citing numerous earlier references.

Magnetic resonance nephrourographic techniques and applications: how we do it

Chronic kidney disease is a significant public health problem, and a comprehensive evaluation of renal disease often requires accurate evaluation of both kidney structure and function. Magnetic resonance (MR) nephrourography refers to newly developed imaging techniques that have the ability to provide a quantitative assessment of renal function, especially glomerular filtration rate and renal blood flow. Our review outlines several different methodologies that are present in the literature and also details the specifics of our own methods for renal imaging. Though varied, all MR imaging methods use the common steps of image acquisition, image postprocessing, and tracer kinetics modeling of the processed image data. The optimal methodology should be practical and based primarily on simplicity, speed, and reproducibility. The combination of anatomic and quantitative functional information of the kidneys provided by MR imaging allows for a safe, comprehensive evaluation of renal disease, with particular utility in the settings of urinary tract obstruction and renal transplantation.