In utero management of fetal lower urinary tract obstruction with a novel shunt: a landmark development in fetal therapy

Lifesaving Treatments for the Tiniest Patients-A Narrative Description of Old and New Minimally Invasive Approaches in the Arena of Fetal Surgery

Fetal surgery has become a lifesaving reality for hundreds of fetuses each year. The development of a formidable spectrum of safe and effective minimally invasive techniques for fetal interventions since the early 1990s until today has led to an increasing acceptance of novel procedures by both patients and health care providers. From his vast personal experience of more than 20 years as one of the pioneers at the forefront of clinical minimally invasive fetal surgery, the author describes and comments on old and new minimally invasive approaches, highlighting their lifesaving or quality-of-life-improving potential. He provides easy-to-use practical information on how to perform partial amniotic carbon dioxide insufflation (PACI), how to assess lung function in fetuses with pulmonary hypoplasia, how to deal with giant CPAMS, how to insert shunts into fetuses with LUTO and hydrothorax when conventional devices are not available, and how to resuscitate a fetus during fetal cardiac intervention. Furthermore, the author proposes a curriculum for future fetal surgeons, solicits for the centralization of patients, for adequate maternal counseling, for adequate pain management and adequate hygienic conditions during interventions, and last but not least for starting the process of academic recognition of the matured field as an independent specialty. These steps will allow more affected expectant women and their unborn children to gain access to modern minimally invasive fetal surgery and therapy. The opportunity to treat more patients at dedicated centers will also result in more opportunities for the research of rare diseases and conditions, promising even better pre- and postnatal care in the future.

Development and in-vitro characterization of a novel fetal vesicoamniotic shunt - the Vortex Shunt

OBJECTIVES

To develop and test a novel vesicoamniotic shunt (VAS) to treat fetal lower urinary tract obstruction (LUTO), decrease dislodgement and optimize shunt deployment in-vitro.

METHODS

VAS design objectives included: 1) robust and atraumatic fixation elements, 2) kink resistant conduit to adjust to fetal movement and growth, 3) one-way pressure valve to facilitate bladder cycling, and 4) echogenic deployment visualization aids. The force to dislodge the novel Vortex shunt was compared with existing commercially available shunts in a bench-top porcine bladder model. Sonographic echogenicity was evaluated with ultrasound-guided deployment, and the shunt valve pressure measured.

RESULTS

A prototype novel Vortex shunt was developed using braided nitinol "umbrella-type" ends with a kink-resistant stem incorporating an internal one-way valve. The peak force required to dislodge the Vortex shunt was significantly higher than commercially available shunts (p<0.01). Shunt deployment in the bench-top model was easily confirmed with ultrasound guidance and the brisk decompression of the inflated porcine bladder thereafter. In-vitro valve gauge pressure testing mirrored bladder pressures in human LUTO cases.

CONCLUSION

In-vitro testing shows that the Vortex shunt may improve deployment, sonographic visualization, kink resistance, and dynamic size adjustment. Validation in preclinical animal models are warranted and currently underway. This article is protected by copyright. All rights reserved.

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.

Current perspective and scope of fetal therapy: part 1

Fetal therapy term has been described for any therapeutic intervention either invasive or noninvasive for the purpose of correcting or treating any fetal malformation or condition. Fetal therapy is a rapidly evolving specialty and has gained pace in last two decades and now fetal intervention is being tried in many malformations with rate of success varying with the type of different fetal conditions. The advances in imaging techniques have allowed fetal medicine persons to make earlier and accurate diagnosis of numerous fetal anomalies. Still many fetal anomalies are managed postnatally because the fetal outcomes have not changed significantly with the use of fetal therapy and this approach avoids unnecessary maternal risk secondary to inutero intervention. The short-term maternal risk associated with fetal surgery includes preterm labor, premature rupture of membranes, uterine wall bleeding, chorioamniotic separation, placental abruption, chorioamnionitis, and anesthesia risk. Whereas, maternal long-term complications include risk of infertility, uterine rupture, and need for cesarean section in future pregnancies. The decision for invasive fetal therapy should be taken after discussion with parents about the various aspects like postnatal fetal outcome without fetal intervention, possible outcome if the fetal intervention is done, available postnatal intervention for the fetal condition, and possible short-term and long-term maternal complications. The center where fetal intervention is done should have facility of multi-disciplinary team to manage both maternal and fetal complications. The major issues in the development of fetal surgery include selection of patient for intervention, crafting effective fetal surgical skills, requirement of regular fetal and uterine monitoring, effective tocolysis, and minimizing fetal and maternal fetal risks. This review will cover the surgical or invasive aspect of fetal therapy with available evidence and will highlight the progress made in the management of fetal malformations in last two decades.

Unusual fetal ascites and spontaneous bladder rupture in a female fetus: a case report

BACKGROUND

Fetal bladder rupture causing urinary ascites is uncommon. It is generally related to invasive fetal medicine procedures or obstructive disorders such as in posterior urethral valves in male fetuses. An exceptional case of spontaneous bladder rupture in a female fetus occurred in a pregnant woman treated with high doses of opiates in an intensive care unit. This unusual obstetric situation leads to discussion of the possible causes of fetal bladder rupture, its management, and the pediatric prognosis.

CASE PRESENTATION

We report the case of a 30-year-old nulliparous black woman with a history of mesenteric cystic lymphangioma and multiple bowel resections leading to chronic malabsorption. During her pregnancy, our patient presented with an occlusive syndrome and major bilateral renal dilation. Urinary derivation resulted in iatrogenic bilateral ureteral perforation. Our patient thus presented with major uroperitoneum, bilateral pleural effusion and acute renal failure, treated by thoracic drainage and bilateral nephrostomy. Postoperative pain required treatment with level III analgesics. In this context, 5 days after morphine treatment introduction an enlarged fetal bladder was observed, followed 3 days later by voluminous fetal ascites. The diagnosis of spontaneous bladder rupture was suspected. After multidisciplinary discussion, expectant management was decided. At 31 weeks and 4 days gestation, our patient went into spontaneous labor with a subsequent vaginal delivery. The infant required resuscitation and paracentesis of ascites at birth. Her neonatal course was favorable with a simple urethral bladder drainage. Cystography at day 9 was normal. At 2 years of follow-up, the mother and the child have a normal course.

CONCLUSIONS

An iatrogenic origin of megacystis in a female fetus must be evoked in the event of maternal administration of high doses of opiates in the second part of her pregnancy. In our case, the megacystis was followed by spontaneous bladder rupture at 30 weeks of gestation, with a favorable maternal fetal issue.

Clinical predictors of chronic kidney disease in congenital lower urinary tract obstruction

Congenital lower urinary tract obstruction is associated with oligohydramnios and significant perinatal mortality and long-term chronic kidney disease. The counseling of families facing this diagnosis, especially when prenatal intervention is proposed, is fraught with ambiguity. This review aims to equip the provider with the current evidence behind the conventional and novel biomarkers predictive of chronic kidney disease. The relevant clinical predictors are categorized by when they are identified, antenatally or postnatally, and as either anatomic or chemical. They are considered for their prognostic value and the challenges in obtaining them, specifically the risk to the fetus in the case of prenatal biomarkers. Serum creatinine in infancy is the traditional chemical biomarker of kidney function and continues to be a consistent predictor of future serum creatinine. β-2 microglobulin may provide earlier information regarding fetal glomerular and tubular function and is also predictive of long-term serum creatinine. Renal parenchymal area is an anatomic surrogate of nephron mass that is used in both prenatal and postnatal settings. Understanding the anatomic and chemical biomarkers is essential for future refinement of the staging algorithm used to distinguish which patients may benefit from early in utero intervention.

Advanced ultrasound for prenatal interventions

Ultrasound is an integral part of prenatal interventions. Doppler studies and 3-dimensional ultrasound (3DUS) are frequently used to determine whether fetal surgery is required. The operator's experience remains crucial for reducing procedure-related morbidity. Real-time 3DUS (or 4DUS) can simultaneously display the needle tip in three orthogonal planes, providing reassurance that no fetal parts are in the path. In experienced hands, 4DUS guidance may not be more effective than B-mode, but its value for less-experienced operators remains to be determined. Recent developments in needle, shunt, and video endoscopic technologies may compliment the use of image-guided in utero procedures. Future developments of higher-dimensional transducers and image software may improve the utility of ultrasound for invasive obstetric interventions.

A classic twin study of lower urinary tract obstruction: Report of 3 cases and literature review

OBJECTIVE

The aim of the present study was to investigate genetic effects in the formation of congenital lower urinary tract obstruction (LUTO) comprising posterior urethral valves (PUV), urethral atresia, and urethras with variable degrees of stenosis.

METHODS

A classic twin study was performed by assessing LUTO twin pairs from the literature. Furthermore, data regarding 3 previously unreported twin pairs with PUV from University of Bonn, Essen and Wrocławs own in-house databases were added. Both pair- and probandwise concordance rates were calculated and compared for monozygotic (MZ) and dizygotic (DZ) twin pairs.

RESULTS

The pairwise concordance rates for all LUTO were 53% (95% confidence interval [CI] 32%-73%) and 17% (95% CI 3%-56%) for MZ and DZ twin pairs, respectively (P = .180). The probandwise concordance rates were 69% (95% CI 51%-83%) and 29% (CI 95% 8%-64%) for MZ and DZ twin pairs respectively (P = .084). The MZ/DZ ratios of the pair- and probandwise concordance rates were 3.1 and 2.4, respectively.

CONCLUSION

The present study did not show significant differences in comparisons of concordance rates of MZ and DZ twin pairs, probably due to the small number of twin pairs reported. However, the more than 2-fold higher pair- and probandwise concordance rates for MZ versus DZ twin pairs are very suggestive of a contribution of genetic factors to the development of LUTO.

Fetal surgery: a critical review

Therapeutic fetal surgical procedures are predicated upon the ability to make an accurate fetal diagnosis. The earliest open fetal surgical procedures were introduced in the 1960s to treat Rh isoimmunisation. They were introduced when it became possible to predict impending fetal demise. Open procedures were abandoned when percutaneous approaches proved superior. The introduction of fetal ultrasound allowed the diagnosis of other congenital anomalies, some being amenable to fetal interventions. Open fetal surgical procedures were initially utilised, with significant maternal morbidity. For some anomalies, percutaneous approaches became favoured. In general, all of these procedures involved significant risks to the mother, to save a baby that was likely to die before or shortly after birth without fetal intervention. Fetal repair for myelomeningocele was a "sea change" in approach. The same maternal risks were taken to improve the quality of life of the affected fetus, not save its life. The completion of the "MOMs Trial" has occasioned a "tsunami" of centres in North America applying this approach. Others are attempting percutaneous repairs, with mixed results. This paper reviews the history of fetal surgery, focusing on the themes of the tension between accurate diagnosis and prognosis and open versus "minimally invasive" approaches.

Vesico-amniotic shunting for lower urinary tract obstruction in a fetus with VACTERL association

Newborn cases of VACTERL association with lower urinary tract obstruction (LUTO) are rare and there have been no reports on those patients undergoing fetal therapy in English literature. We successfully performed vesico-amniotic shunting in a fetus having LUTO caused by abnormality of the external genitalia at 16 weeks' gestation. Although fetal karyotype was normal 46XY, follow-up fetal ultrasound examinations revealed ventriculomegaly in the brain, a small stomach and a right multicystic dysplastic kidney. MRI at 31 weeks' gestation suggested lobar type holoprosencephaly. Diagnosis of VACTERL association was confirmed postnatally. We consider that vesico-amniotic shunting is indicated for a fetus of VACTERL association with LUTO if the parents wish the procedure after genetic counseling and explanations about the fetal conditions.

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.

Congenital Anomalies of the Kidney and the Urinary Tract (CAKUT)

This article reviews the majority of Congenital Anomalies of the Kidney and Urinary Tract (CAKUT) with emphasis in Pediatric Pathology describing and illustrating lesions as varied as ureteral duplications, ureteropelvic junction obstruction, horseshoe kidney, posterior urethral valve and prune belly syndrome, obstructive renal dysplasia, nonmotile ciliopathies and several syndromes associated with renal malformations (Meckel-Joubert, short rib, Bardet-Biedl, asplenia/polysplenia, hereditary renal adysplasia, Zellweger, trisomies, VACTER-L, Potter, caudal dysplasia, and sirenomelia), as well as ADPK, and ARPK. The purpose of this review is not only to describe the congenital renal anomalies, but also to analyze the more recent therapeutic interventions that may modify the natural history of some of these severe conditions.

Fetal lower urinary tract obstruction and its management

INTRODUCTION

Prenatal counselling in case of fetal obstructive uropathies still represents a clinical dilemma, despite ultrasound detection of lower urinary tract obstruction has greatly advanced during recent years as well as fetal intervention techniques.

MATERIALS AND METHODS

A systematic review of the relevant literature on the topic was performed, with a special focus on the role of antenatal ultrasound, in utero treatment and prognosis.

CONCLUSIONS

A clinico-diagnostic flow chart was developed, with the specific aim of aiding health care givers in the clinical management and the parental decision-making process.

Fetal surgery for severe lower urinary tract obstruction

Fetal interventions have been proposed for treatment of severe lower urinary tract obstruction (LUTO), as this condition is associated with high rates of perinatal mortality and postnatal renal impairment. The rationale for in utero treatment for those cases is based on the possibility of relieving the obstruction, improving the amniotic fluid volume, and preventing renal and bladder damage. Candidates for fetal intervention should be rigorously selected based on the confirmation of severe LUTO (dilated bladder and bilateral hydronephrosis), oligohydramnios or anyhydramnios and 'favorable' fetal urinalysis (dependent on gestational age). Nowadays there are two different therapeutic options with specific technical approaches. Vesico-amniotic shunting is an easier procedure, but with a higher frequency of related complications. Fetal cystoscopy can be used for diagnostic purpose and for treatment of posterior urethral valves, with suggestive advantage of allowing a more physiological release of the obstruction. According to the literature, estimated survival rates and postnatal normal renal function frequencies are approximately 40 and 50% after vesico-amniotic shunting and 75 and 65% after fetal cystoscopy, respectively.

Feasibility of vesicoamniotic shunt insertion in an inanimate model: comparison of fetoscopic and ultrasound-guided techniques

OBJECTIVES

To determine the feasibility of fetoscopic vesicoamniotic shunt insertion (F-VASI) in an inanimate model and to compare F-VASI to ultrasound (US)-guided VASI (US-VASI) with respect to accuracy of shunt placement and overall success rate.

METHODS

An inanimate second-trimester fetus with a replaceable bladder balloon was suspended in a pressurized water tank and localized with US. Fetal position was randomized, the operator was blinded and a 5-Fr Harrison Shunt® decompressed the bladder in both groups. Thirty shunt insertions were performed per group.

RESULTS

Procedure time was longer for F-VASI (15.0 vs. 2.8 min, p < 0.05), although it decreased with practice. F-VASI and US-VASI were similar for adequate depth of insertion (27/30 vs. 27/30, p = 1.0), placement within 1 cm of midline (27/30 vs. 25/30, p = 0.42), bladder puncture (28/30 vs. 28/30, p = 1.0), and overall success rate (27/30 vs. 23/30, p = 0.3).

CONCLUSIONS

F-VASI is feasible in an inanimate model. Overall success rate was similar between the groups, although procedure time was longer for F-VASI. Further study is required to determine whether shunt migration is decreased with F-VASI.