Fetal intervention for myelomeningocele: effect on postnatal bladder function

Stratification of neurogenic bladder risk in spina bifida using the urinary peptidome

Neurogenic bladder poses a major morbidity in children with spina bifida (SB), and videourodynamic studies (VUDS) are used to stratify this risk. This small-scale pilot study utilized current mass-spectrometry-based proteomic approaches to identify peptides or proteins in urine that may differentiate children at high risk of developing renal complications from a neurogenic bladder. Twenty-two urine samples of which nine had high bladder pressure storage that put the upper urinary tract at risk, while 13 with a lower risk for renal compromise were analyzed. More than 1,900 peptides across all 22 samples were quantified, and 115 peptides differed significantly (P < 0.05) between the two groups. Using machine learning approaches five peptides that showed the greatest differences between these two clinical categories were used to build a classifier. We tested this classifier by blind analysis of an additional six urine samples and showed that it correctly assigned the unknown samples in their proper risk category. These promising results indicate that a urinary screening test based on peptides could be performed on a regular basis to stratify the neurogenic bladder into low or high-risk categories. Expanding this work to larger cohorts as well as across a broad spectrum of urodynamics outcomes may provide a useful diagnostic test for neurogenic bladder.NEW & NOTEWORTHY This approach could help risk stratify the neurogenic bladder in patients with spina bifida and could allow us to safely defer on up to 1/3 of urodynamic studies. These pilot data justify a larger trial before this approach becomes a clinical tool.

Prevalence of high-risk bladder categorization with prenatal and postnatal myelomeningocele repair types

INTRODUCTION

Urologic substudies of prenatal myelomeningocele (MMC) closure have focused primarily on continence without significant clinical benefit. Fetoscopic MMC repair (FMR) is a newer form of prenatal intervention and touts added benefits to the mother, but urological outcomes have yet to be analyzed. We set out to focus on bladder safety rather than continence and examined bladder outcomes with different prenatal MMC repairs (FMR and prenatal open [POMR]) and compared bladder-risk-categorization to traditional postnatal repair (PSTNR).

METHODS

An IRB-approved retrospective analysis of all patients undergoing all forms of MMC repairs with inclusion and exclusion criteria based on the MOMS trial was performed. Bladder safety assessment required initial urodynamic studies (UDS), renal bladder ultrasound (RBUS), and/or voiding cystourethrogram (VCUG) within the 1st year of life. Follow-up analyses within the cohorts required follow-up studies within 18 months after initial evaluations. Outcomes assessed included bladder-risk-categorization based on the CDC UMPIRE study (high, intermediate, and safe), hydronephrosis (HN), and vesicoureteral reflux (VUR). A single reader evaluated each UDS.

RESULTS

Initial UDS in 93 patients showed that the prevalence of high-risk bladders were 35% FMR versus 36% PSTNR and 60% POMR. Follow-up UDS showed only 8% of FMR were high-risk compared to 35% POMR and 36% PSTNR. Change from initial to follow-up bladder-risk-category did not reach significance (p = .0659); however, 10% PSTNR worsened to high-risk on follow-up, compared to none in either prenatal group. Subanalysis of follow-up UDS between the prenatal cohorts also was not significant (p = .055). Only 8% of FMR worsened or stayed high-risk compared to 35% with POMR (p = .1). HN was significantly different at initial and subsequent follow up between the groups with the least in the FMR group.

CONCLUSIONS

Early outcome UDS analyses demonstrated lower incidence of high-risk bladders in FMR patients with a trend toward clinically significant improvement compared to POMR in regard to all evaluated metrics. Larger, prospective, confirmatory studies are needed to further evaluate the potential benefits on FMR on bladder safety and health.

Urological Outcome after Fetal Spina Bifida Repair: Data from the Zurich Cohort

INTRODUCTION

Neurogenic lower urinary tract dysfunction (NLUTD) represents a severe burden for patients with open spina bifida (OSB). The effect of fetal OSB repair on the urological outcome remains unclear, as controversial data exist. The aim of this study was to further increment existing outcome data and to demonstrate that our earlier published positive preliminary results are not erratic.

METHODS

Data from standardized urological follow-up appointments of patients with fetal OSB repair operated at our center were analyzed. Data were obtained from urodynamic studies (UDSs) and radiologic exams performed in the newborn (gestational age 37-39 weeks), at ages of 6, 12, 18, and 24 months, and then at yearly intervals.

RESULTS

Of 82 patients (mean age 2.6 years, range 6 months to 7 years), 26 (32%) had a normal bladder function as demonstrated by UDSs. Of the 56 (68%) patients with NLUTD, 29 (51%) patients showed initially a normal UDS, but developed NLUTD in the follow-up, 19 (66%) of them spontaneously and another 10 (34%) in association with growth and development, or surgery of inclusion cysts. Radiologic abnormalities (upper tract dilatation and vesico-uretero-renal reflux) were seen in 15%, mainly patients with NLUTD.

CONCLUSION

Our results add an important set of information to the existing body of evidence. The data reconfirm our earlier published favorable preliminary results and support other studies that show a possible benefit of prenatal OSB repair on the urological outcome, but they also demonstrate that the positive effect remains limited.

Evaluation and Long-term Management of Neurogenic Bladder in Spinal Dysraphism

Spinal dysraphism, which includes conditions such as myelomeningocele and sacral agenesis, is one of the most common causes of congenital lower urinary tract dysfunction. Early evaluation of the neurogenic bladder serves to minimize renal damage, and the main goals of management include preserving renal function, achieving acceptable continence, and optimizing quality of life. The survival of patients with such conditions has improved to greater than 80% reaching adulthood, owing to advances in diagnostic and therapeutic modalities. The result is a real, and unfortunately often unmet, need for successful transitional care in this complex patient population. Clinicians must be able to identify the unique challenges encountered by patients with neurogenic bladder as they shift through different stages of their life.

Fetal open spinal dysraphism repair through a mini-hysterotomy: Influence of gestational age at surgery on the perinatal outcomes and postnatal shunt rates

OBJECTIVE

To analyze the impact of gestational age (GA) at the time of fetal open spinal dysraphism (OSD) repair through a mini-hysterotomy on the perinatal outcomes and the infants' ventriculoperitoneal shunt rates.

METHODS

Retrospective study of cases of fetal OSD correction performed from 2014 and 2019.

RESULTS

One hundred and ninety women underwent fetal surgery for OSD through a mini-hysterotomy, and 176 (176/190:92.6%) have since delivered. Fetal OSD correction performed earlier in the gestational period, ranging from 19.7 to 26.9 weeks, was associated with lower rates of postnatal ventriculoperitoneal shunting (P: .049). Earlier fetal surgeries were associated with shorter surgical times (P: .01), smaller hysterotomy lengths (P < .001), higher frequencies of hindbrain herniation reversal (P: .003), and longer latencies from surgery to delivery (P < .001). Median GA at delivery was 35.3 weeks. Multivariate binary logistic regression showed that both fetal lateral ventricle-to-hemisphere ratio (%; P < .001; OR: 1.14 [95% CI: 1.09-1.21]) and GA at the time of fetal surgery (P: .016; OR: 1.37 [95% CI: 1.07-1.77]) were independent predictors of postnatal ventriculoperitoneal shunting.

CONCLUSION

Fetuses with OSD who were operated on earlier in the gestational interval, which ranged from 19.7 to 26.9 weeks, were less prone to receiving postnatal ventriculoperitoneal shunts.

Fetal repair of myelomeningocele: current status and urologic implications

Over the last 40 years, vast changes have occurred in the care of children with open neural tube defects. Not only has newborn survival dramatically improved but survival into adulthood has improved as well. Now, the ability to accurately identify and repair myelomeningocele (MMC) lesions before birth has become a reality. Pioneering efforts at several institutions in the United States paved the way for such advancements in care. Substantial data now exist to support the positive benefits of fetal MMC repair from a neurosurgical standpoint, chiefly the significant reduction in hindbrain herniation, decrease in shunt-dependent hydrocephalus, and improvement in lower-extremity motor function. However, until only recently, the urological impact of fetal repair has not been nearly as positive overall. Multiple retrospective reports of newborn bladder function from the United States suggest that prenatal repair has provided neither short-term nor long-term improvements in bladder function. Yet, the retrospective nature of these data and their focus upon urodynamic studies (UDS) parameters have hampered the ability to draw conclusions. Recently, published data from the landmark Management of Myelomeningocele Study indicate that fetal repair may improve certain aspects of bladder function when compared with conventional repair. This review provides an overview of the history and timeline of fetal repair in the United States and brings the reader quickly up to date on the current impact of repair on both neurosurgical and urological outcomes.

Neurological dysfunction of the bladder from myelomeningocele

Myelomeningocele (MMC) affects approximately 2000 infants in the US yearly and causes long-term damage to the genitourinary system. There is a wide spectrum of effects on the bladder and urethral sphincter that do not correlate with the level of the spinal cord defect. The bladder changes can provide a safe storage pressure, often at the expense of continence, or can create a hostile environment leading to increased pressure on the kidneys and eventually to chronic kidney disease. The ultimate goals in management are to maintain a safe system that prevents renal deterioration, while providing social continence and independence in the long term. This review intends to provide an overview of the effects of MMC on the genitourinary system, regardless of intervention, in order to understand the pathophysiology of the disease.

Low level myelomeningoceles: do they need prenatal surgery?

BACKGROUND

Postnatal closure of a myelomeningocele remains the standard of care in many countries. The prenatal closure has given hope for decreasing the damage to the neural placode and has challenged classic management. However, this technique presents potential sources of complications. Patients with MMC with an anatomical level of L4 and below have a better functional prognosis than higher level malformations. Are they still candidates for prenatal surgery?

OBJECTIVE

To evaluate outcome of MMC with an anatomical level of L4 and below and discuss, with support of the literature, the indications to perform prenatal closure in this particular group of patients.

MATERIALS AND METHODS

Twenty-nine children were included in this observational study. The level of the vertebral malformation was sacral in 12 cases (41.4%) or lumbar (level ≤ L4) in 17 cases (58.6%). All the patients was operated postnatally for closure of the MMC with microsurgical technique as soon as possible after clinical evaluation (range 0-97 days).

RESULTS

Only 11 out of 29 patients (37.9%) needed of a CSF diversion. A Chiari II malformation was present before MMC closure in 17 patients (58.6%) and only in 5 (17%) after. Twenty-six patients (89.7%) were able to walk. Seven (23%) and 16 (55%) of our patients have a normal bladder and bowel control, respectively. All school-aged children attend school.

CONCLUSIONS

The functional outcome for low-level MMC is good when managed with modern microneurosurgical techniques with a low risk for the patient and the mother. Therefore, we do not suggest prenatal surgery for subgroup of infant with MM.

Effectiveness of Prenatal Intervention on the Outcome of Diseases That Have a Postnatal Urological Impact

We reviewed the literature addressing outcomes of fetal intervention of conditions that require post-natal urological management including lower urinary tract obstruction, hydrometrocolpos, congenital adrenal hyperplasia, and myelomeningocele. Despite several decades of fetal intervention for these conditions, benefits remain elusive in part because of the enormous difficulty of conducting prospective randomized studies. In this review, we reached the following conclusions: Prenatal intervention in lower urinary tract obstruction (LUTO) improves survival in the worst cases by improving pulmonary function and it may be advantageous for renal function, particularly in patients with adverse urine parameters.Prenatal treatment of female fetuses at risk of having congenital adrenal hyperplasia (CAH) reduces virilization. Non-invasive fetal DNA analysis allows earlier diagnosis, reducing the risk of treating with dexamethasone males and non-affected fetuses.Fetal treatment of myelomeningocele (MMC) is gaining momentum. Prospective studies including standardized urologic evaluation will determine if the encouraging results reported by some hold on the long term follow-up.

Prenatal myelomeningocele repair improves urinary continence and reduces the risk of constipation

AIMS

The aim of the study was to evaluate the lower urinary tract function, frequency UTI, the degree of social urine continence, and the occurrence of constipation in children who underwent prenatal or postnatal surgery for MMC.

MATERIALS AND METHODS

Seventy-two patients with MMC were assessed and divided into the prenatal group (36 patients) and the postnatal one (36 patients). All children, regardless the time of operation, received the same treatment after birth. The urodynamic tests, USG, cystourethrography were performed in all patients along with evaluation of the UTI's, social urine continence, and presence of constipation.

RESULTS

Urodynamic and imaging studies showed no differences between the test groups. Children from the prenatally operated group showed statistically significant lower number of urinary tract infections, better urine continence, and less frequent constipation.

CONCLUSIONS

Prenatal MMC repair ensures statistically significant improvement of the degree of social urinary continence, reducing the risk of urinary infections and constipation. Time of MMC repair does not statistically influence the urodynamic tests results and the urodynamic parameters are not the prognostic elements to assess the social urinary continence possibility in patients with the neurogenic bladder.

Current State of Fetal Intervention for Lower Urinary Tract Obstruction

PURPOSE OF THE REVIEW

In this article, we explore the origins of intervention of fetal lower urinary tract obstruction, and we specifically discuss the background and recent outcomes of vesicoamniotic shunt placement and fetal cystoscopy. The article seeks to provide a comprehensive overview of the field while bringing the reader quickly up to speed on the pertinent literature and the critical data that are available to guide decision-making regarding intervention.

RECENT FINDINGS

Appropriate patient selection for fetal intervention remains challenging despite advances in prenatal imaging. Both a randomized controlled trial and multiple systematic reviews show evidence of a perinatal survival benefit following fetal intervention but rates of renal morbidity remain very high. Despite 30 years of research, fetal lower urinary tract obstruction remains a difficulty entity to treat. Intervention may lead to survival, but physicians and caregivers must remain alert for the distinct possibility of long-term renal morbidity in survivors.

Early postnatal bladder function in fetoscopic myelomeningocele repair patients

PURPOSE

Prenatal repair of myelomeningocele (MMC) via hysterotomy has demonstrated neurosurgical and motor benefits, when compared to postnatal repairs. Urologic benefits, however, remain to be seen. The purpose of this study was to review early postnatal bladder function in patients undergoing a novel endoscopic approach for MMC repair using an exteriorized uterus.

METHODS

A prospective urologic assessment of patients undergoing fetoscopic MMC repair and receiving subsequent care at our facility, was performed. Patients were managed and urodynamic studies risk-stratified according to the Centers for Disease Control and Prevention Urologic and Renal Protocol for the Newborn and Young Child with Spina Bifida.

RESULTS

Fetoscopic MMC repair was performed in 14 patients. No patients had hydronephrosis or bladder thickening at birth. Detrusor overactivity was observed in nine (64.3%) patients. Impaired compliance was seen in eight (57.1%) patients. No patients had a detrusor leak point pressure of > 40 cm H2O or evidence of detrusor sphincter dyssynergia. Three (21.4%) patients had vesicoureteral reflux, seven (50.0%) had an open bladder neck, and none had trabeculated bladders.

CONCLUSION

In this early experience with fetoscopic MMC repair, postnatal bladder function does not appear to be any worse than that of previously reported prenatal or postnatal closures.

A 4-Year Prospective Urological Assessment of In Utero Myelomeningocele Repair-Does Gestational Age at Birth Have a Role in Later Neurogenic Bladder Pattern?

PURPOSE

Premature delivery is a major complication of in utero myelomeningocele repair. The prematurity rate in MOMS (Management of Myelomeningocele Study) was 79%, with a mean gestational age at birth of 34 weeks. We speculated that prematurity could also influence urological outcome in patients operated on prenatally for myelomeningocele.

MATERIALS AND METHODS

Beginning in November 2011, we prospectively followed a population of patients with myelomeningocele who had undergone in utero repair.

RESULTS

We compared patients based on gestational age at birth, ie younger than 34 weeks (group 1, 42 patients) and 34 weeks or older (group 2, 37 patients). Mean gestational age at birth was 28.3 weeks (range 25 to 33) in group 1 and 35.2 weeks (34 to 38) in group 2. Of the cases 47.5% in group 1 were classified as high risk, 35% as incontinent, 10% as hypocontractile and 7.5% as normal. By comparison, 54.5% of cases in group 2 were classified as high risk, 33.3% as incontinent and 12.1% as normal. Differences between the groups were not statistically significant. Mean followup was 27.9 months in group 1 and 24.3 months in group 2.

CONCLUSIONS

Our results show that gestational age at birth has little impact on bladder pattern. These data reinforce the need to follow this population closely.

Bladder Function After Fetal Surgery for Myelomeningocele

BACKGROUND

A substudy of the Management of Myelomeningocele Study evaluating urological outcomes was conducted.

METHODS

Pregnant women diagnosed with fetal myelomeningocele were randomly assigned to either prenatal or standard postnatal surgical repair. The substudy included patients randomly assigned after April 18, 2005. The primary outcome was defined in their children as death or the need for clean intermittent catheterization (CIC) by 30 months of age characterized by prespecified criteria. Secondary outcomes included bladder and kidney abnormalities observed by urodynamics and renal/bladder ultrasound at 12 and 30 months, which were analyzed as repeated measures.

RESULTS

Of the 115 women enrolled in the substudy, the primary outcome occurred in 52% of children in the prenatal surgery group and 66% in the postnatal surgery group (relative risk [RR]: 0.78; 95% confidence interval [CI]: 0.57-1.07). Actual rates of CIC use were 38% and 51% in the prenatal and postnatal surgery groups, respectively (RR: 0.74; 95% CI: 0.48-1.12). Prenatal surgery resulted in less trabeculation (RR: 0.39; 95% CI: 0.19-0.79) and fewer cases of open bladder neck on urodynamics (RR: 0.61; 95% CI: 0.40-0.92) after adjustment by child's gender and lesion level. The difference in trabeculation was confirmed by ultrasound.

CONCLUSIONS

Prenatal surgery did not significantly reduce the need for CIC by 30 months of age but was associated with less bladder trabeculation and open bladder neck. The implications of these findings are unclear now, but support the need for long-term urologic follow-up of patients with myelomeningocele regardless of type of surgical repair.

Urological Results after Fetal Myelomeningocele Repair in Pre-MOMS Trial Patients at the Children's Hospital of Philadelphia

Introduction: Myelomeningocele patients deal with multiple medical issues, including lower extremity neurological deficits, bowel and bladder incontinence and the sequelae of hydrocephalus secondary to a Chiari II malformation. In utero intervention holds the promise of reversing some of the sequelae and improving outcome. Material and Methods: Between 1998 and 2003 (preceding the formal Management of Myelomeningocele Study, MOMS), an initial group of 58 patients underwent in utero repair of their myelomeningocele between 21 and 25 weeks' gestation. Long-term (5-year) follow-up has occurred in this cohort of patients. Previous reports have documented decreased incidence of ventriculoperitoneal shunting and neuromotor functioning, showing improved outcomes compared with historical controls. Results: Overall, 4 fetal deaths occurred, while the majority of patients returned for follow-up for up to 5 years after closure. Phone follow-up has also been conducted for those who could not return. To date, 10 patients (18.5%) have successfully toilet-trained, while 2 patients have bowel continence and 1 has bladder continence but requires enemas; 2 patients who successfully toilet-trained developed spinal dermoid cysts requiring surgical resection. Discussion: Historically, in utero repair of myelomeningocele patients yields a greater percentage of patients who have achieved continence compared with those undergoing postnatal repair. The MOMS trial will compare contemporary urological outcomes of those patients undergoing either prenatal or postnatal repair in a randomized fashion. The results of this trial showed a decreased need for ventriculoperitoneal shunting in those patients who underwent in utero repair as well as an improvement in lower extremity function.

Bladder changes after several coverage modalities in the surgically induced model of myelomeningocele in lambs

OBJECTIVE

To assess the presence of early bladder abnormalities in a prenatally corrected and uncorrected animal model of Myelomeningocele (MMC).

METHOD

A MMC-like lesion was surgically created in 18 fetal lambs between the 60th and the 80th day of gestation. Eight of them did not undergo fetal repair (group A), three were repaired with an open two-layer closure (group B), three using BioGlue® (groupC) and four fetoscopically (group D). At term, bladders were examined macroscopically and histopathological changes were assessed using H-E and Masson Trichrome.

RESULTS

Five animals in group A (5/8, 62%), two in group B (2/3, 66%), one in group C (1/3, 33%) and one in group D (1/4, 25%) survived. Macroscopically bladders in group A were severely dilated and showed thinner walls. Microscopically they showed a thin layer of colagenous tissue (Blue layer. BL) lying immediately subjacent to the urothelium. The muscular layers were thinner. Non compliant pattern with thick wall and low capacity was also found in the non corrected model. Group B and the control showed preservation of muscular layers and absence of BL. Groups C and D presented BL but also preservation of muscular layers.

CONCLUSION

Bladder changes in a surgically-induced model of MMC can be described using histopathological data. Both extremes of bladder changes can be observed in the model. These changes were completely prevented with open fetal surgery and partially with other coverage modalities.

[Prenatal repair of myelomeningocele: State of the art]

Myelomeningocele is characterized by the extrusion of the spinal cord into a sac filled with cerebrospinal fluid. One part of the postnatal disabilities could be related to the spinal damage and to the cerebral repercussion of the leak of cerebrospinal fluid from the defect. Several experimental studies in animals have demonstrated that a surgical repair of the lesion at middle gestation reduced the postnatal disabilities. These results were confirmed in humans by the Management of Myelomeningocele (MOM) Trial. However, the prenatal surgical repair is associated with maternal and fetal morbidity.

THE PRENATAL MANAGEMENT OF NEURAL TUBE DEFECTS: TIME FOR A RE-APPRAISAL

The prevalence of neural tube defects (NTD) in Europe is around 9 per 10,000 births making it one of the most frequent congential anomalies affecting the central nervous system. NTD encompass all anomalies that are secondary to failure of closure of the neural tube. In this review, we will first summarize the embryology and some epidemiologic aspects related to NTDs. The review focuses on myelomeningocele (MMC), which is the most common distal closure defect. We will describe the secondary pathologic changes in the central and peripheral nervous system that appear later on in pregnancy and contribute to the condition's morbidity. The postnatal impact of MMC mainly depends on the upper level of the lesion. In Europe, the vast majority of parents with a fetus with prenatally diagnosed NTDs, including MMC, opt for termination of pregnancy, as they are apparently perceived as very debilitating conditions. Animal experiments have shown that prenatal surgery can reverse this sequence. This paved the way for clinical fetal surgery resulting in an apparent improvement in outcome. The results of a recent randomized trial confirmed better outcomes after fetal repair compared to postnatal repair; with follow up for 30 months. This should prompt fetal medicine specialists to reconsider their position towards this condition as well as its prenatal repair. The fetal surgery centre in Leuven did not have a clinical programme for fetal NTD repair until the publication of the MOMS trial. In order to offer this procedure safely and effectively, we allied to a high volume centre willing to share its expertise and assist us in the first procedures. Given the maternal side effects of current open fetal surgical techniques, we have intensified our research programmes to explore minimally invasive alternatives. Below we will describe how we are implementing this.

Fetal surgery for myelomeningocele

Myelomeningocele (MMC) is a congenital neural tube defect that occurs in approximately 1 in 2900 live births in the United States. It is a devastating disability with significant morbidity and mortality within the first few decades of life. MMC was the first nonlethal disease to be considered and studied for fetal surgery and is now the most common open fetal surgery performed. The recently completed MOMS randomized controlled trial has shown that fetal repair for MMC can improve hydrocephalus and hindbrain herniation, can reduce the need for vetriculoperitoneal shunting, and may improve distal neurologic function in some patients.

Morphometric analysis of posterior fossa after in utero myelomeningocele repair

OBJECT

Myelomeningocele (MMC) is characterized by a defect in caudal neurulation and appears at birth with a constellation of neuroanatomical abnormalities, including Chiari malformation Type II. The authors investigated the effects of antenatal versus postnatal repair of MMC through a quantitative analysis of morphometric changes in the posterior fossa (PF).

METHODS

The authors retrospectively reviewed the records of 29 patients who underwent in utero MMC repair, 24 patients who underwent postnatal repair, and 114 fetal and pediatric controls. Tonsillar displacement, cerebellum length, pons length, clivus-supraocciput (CSO) angle, and PF area were compared in antenatal and postnatal MMC repair groups as well as in controls without neural tube defects by using t-tests and correlation coefficients.

RESULTS

Initially, the in utero CSO angle was significantly more acute in all patients with MMC--prenatally and postnatally repaired--as compared with controls (57.8° vs 75.4°, p < 0.001); however, the angle rapidly changed and became similar to that in controls between 30 and 31 weeks' gestation to approximately 80°, with antenatal repair having little effect. Postnatally, the CSO angle decreased in controls (R = -0.58) and in the antenatal repair group (R = -0.17). The cerebellum and pons length demonstrated no significant differences in any group. Overall, tonsil descent was corrected in the antenatal repair group as compared with postnatal repair (p < 0.001), and the PF area increased in all 3 groups in utero. Growth was less rapid in patients with MMC compared with controls, but this was corrected by antenatal repair (p = 0.015).

CONCLUSIONS

Myelomeningocele was associated with tonsillar herniation and a smaller PF than in control fetuses. Antenatal surgical repair corrected both abnormalities. The CSO angle began significantly more acutely in patients with MMC, but normalized with development regardless of when surgery was performed. Determining the clinical effects of antenatal repair requires further follow-up.

Amniotic fluid levels of glial fibrillary acidic protein in fetal rats with retinoic acid induced myelomeningocele: a potential marker for spinal cord injury

OBJECTIVE

The objective of this study was to determine whether amniotic fluid levels of glial acidic fibrillary protein (GFAP) would reflect myelomeningocele-related neurodegeneration in the rat model of retinoic acid-induced myelomeningocele, which is a model that is very similar to human myelomeningocele and develops the entire spectrum of disease severity including features of the Chiari II malformation.

STUDY DESIGN

Time-dated (embryonic day 10) pregnant Sprague-Dawley rats were gavage fed 60 mg/kg/bodyweight retinoic acid that had been dissolved in olive oil or olive oil alone. Myelomeningocele, retinoic acid-exposed no myelomeningocele, and control fetuses were harvested at specific time points throughout gestation. A standard set of pinching tests was performed to interrogate the sensorimotor reflex arc of hindpaws and tails. Amniotic fluid-GFAP levels were analyzed by standard enzyme-linked immunosorbent assay techniques.

RESULTS

Amniotic fluid-GFAP levels were similar between groups at embryonic days 14, 16, and 18, respectively. Compared with control fetuses, amniotic fluid GFAP levels were significantly increased in myelomeningocele fetuses at embryonic days 20 and 22 (P < .001). Defect size (P < .001), presence of clubfoot deformity (P = .0004), and absence of sensorimotor function (P < .01) at embryonic day 22 correlated with amniotic fluid-GFAP levels.

CONCLUSION

Amniotic fluid-GFAP levels appear to correlate with spinal cord injury as gestation proceeds in fetal rats with myelomeningocele.

Urologic management of spina bifida

The urologist plays an important role in the multidisciplinary team of physicians who provide care for patients with spina bifida. We review common strategies for managing the urinary tract in these patients. The primary objective in all phases of life is protecting kidney function by minimizing bladder hostility and establishing a good capacity, low-pressure urinary reservoir. Ensuring adequate bladder and bowel continence is also paramount for enhancing self-esteem and independence. Medical therapy incorporating clean intermittent catheterization and antimuscarinic medication is the cornerstone of neurogenic bladder management and often the only intervention required to achieve the above goals. Others may require formal lower urinary tract reconstruction to prevent urinary tract deterioration. As will be shown, current management, while effective, is not supported by strong evidence-based protocols; and the impact of any intervention upon quality of life, while subjectively seen as positive, does not have objective validation. These limitations are recognized and currently the subject of urologic investigation.

Prenatal management of urogenital disorders

Antenatal sonography has markedly increased the detection of urogenital anomalies, including those conditions that lead to significant morbidity and mortality. Prenatal intervention is feasible to arrest and sometimes reverse the sequelae of bladder outlet obstruction but not necessarily renal damage. Myelomeningoceles, the most severe form of spina bifida, can be corrected in utero, with improvements in hydrocephalus seen along with a decreased incidence of ventricular shunting postnatally. Medical therapy to prevent virilization associated with congenital adrenal hyperplasia has been successful, with improved ability to detect its presence prenatally now possible. As further techniques evolve to correct underlying disease processes, it becomes important to critically assess the therapies, particularly with long-term outcome data.

The urologist's role in the management of spina bifida: a continuum of care

Caring for the child with spina bifida necessitates lifelong care by a coordinated team of health care providers, and the urologist plays a vital role in this team. The most important management goal of the urologist is the early establishment and consistent maintenance of a lower pressure urinary reservoir. Ensuring social continence along with its attendant social independence provides some of the greatest management challenges. In those patients who fail medical therapy, surgeons, caregivers, and patients must understand the scope of lower urinary tract reconstruction, the need for strict compliance, and the possibility of future surgery. In this article, we review the recent advances in spina bifida management.

Fetal surgery for myelomeningocele

Fetal intervention for myelomeningocele (MMC) may improve hydrocephalus and hindbrain herniation associated with the Arnold-Chiari II malformation and may reduce the need for ventriculoperitoneal shunting. As of now, there is little evidence that prenatal repair of MMC improves neurologic function. MMC is the first nonlethal disease under consideration and study for fetal surgery. As a result, potential improvements in outcome must be balanced with maternal safety and well-being, in addition to that of the unborn patient.

[Accessibility of legal benefits available in Rio de Janeiro for physically handicapped people]

According to PAHO, only 2 % of Latin America's 85 million disabled people receive adequate medical care. Ten percent of the world's population lives with disabilities without having access to their constitutional rights. Disability must be addressed on several levels: medical, rehabilitative, social and political. Disability is strongly linked to poverty. Stigma, discrimination and inability to pay limit access to health services and education and ill-health increases the treatment cost, creating a vicious circle that must be broken. Although the Constitution grants rights to disabled persons including access to health and education, these legal benefits are not always obtained or respected. To better understand and address the problem, the process for obtaining three of these legal benefits was studied among disabled pediatric patients with myelomeningocele in a specialized Institute in Rio de Janeiro. Results show a low achievement rate. Bureaucracy and the expenses with locomotion were main constrains worsened by lack of time and resources in families struggling with poverty. Other difficulties were lack of professional attention and confidence in the system, problems related to documents, unqualified educational system and locomotion constrains.

Fetal spina bifida repair--current trends and prospects of intrauterine neurosurgery

Myelomeningocele is a common dysraphic defect leading to severe impairment throughout the patient's lifetime. Although surgical closure of this anomaly is usually performed in the early postnatal period, an estimated 330 cases of intrauterine repair have been performed in a few specialized centers worldwide. It was hoped prenatal intervention would improve the prognosis of affected patients, and preliminary findings suggest a reduced incidence of shunt-dependent hydrocephalus, as well as an improvement in hindbrain herniation. However, the expectations for improved neurological outcome have not been fulfilled and not all patients benefit from fetal surgery in the same way. Therefore, a multicenter randomized controlled trial was initiated in the USA to compare intrauterine with conventional postnatal care, in order to establish the procedure-related benefits and risks. The primary study endpoints include the need for shunt at 1 year of age, and fetal and infant mortality. No data from the trial will be published before the final analysis has been completed in 2008, and until then, the number of centers offering intrauterine MMC repair in the USA is limited to 3 in order to prevent the uncontrolled proliferation of new centers offering this procedure. In future, refined, risk-reduced surgical techniques and new treatment options for preterm labor and preterm rupture of the membranes are likely to reduce associated maternal and fetal risks and improve outcome, but further research will be needed.

Delayed intrauterine repair of an experimental spina bifida with a collagen biomatrix

BACKGROUND/PURPOSE

The aim of the study was to evaluate whether a collagen biomatrix is useful for delayed intrauterine coverage of a surgically created spina bifida in a fetal lamb.

METHODS

In 20 fetal lambs, surgery was performed at 72 or 79 days' gestation. In 15 lambs a spina bifida was created surgically. In 8 lambs it was covered with a collagen biomatrix 2 weeks later and in 7 lambs it was left uncovered. Five lambs served as sham operated controls. Neurological examination was performed at 1 week of age and afterwards the lambs were sacrificed for further histological evaluation.

RESULTS

None of the 5 surviving lambs with the defect covered showed loss of spinal function and the architecture of the spinal cord was preserved in 4 of the 5 lambs. In the uncovered group, 1 of the 4 surviving lambs had loss of spinal function, 5 lambs were available for histological evaluation and 4 of them showed disturbance of the architecture of the spinal cord.

CONCLUSIONS

Collagen biomatrices can be used for intrauterine coverage of an experimental spina bifida and can preserve the architecture of the spinal cord. Neurological outcome is not different between fetuses with their spinal cord covered and fetuses with uncovered cords.

Fetal myelomeningocele repair: urologic aspects

PURPOSE OF REVIEW

The notion that earlier surgical correction of congenital anomalies will lead to improved outcomes permeates throughout surgical literature. This review critically assesses some of the urologic evaluations in patients who have undergone fetal repair of their myelomeningoceles.

RECENT FINDINGS

Thus far, there are limited data to determine the effects of such a repair with respect to urologic outcome. Early data, though, have suggested that improvements are being noted in a cohort of patients who have undergone fetal repair of their myelomeningocele with respect to neurodevelopmental outcome and lower extremity neuromotor function.

SUMMARY

What remains to be seen is whether fetal surgery and the noted changes translate into long-term improvement. The efforts being put forth to critically assess the outcomes of such surgery are laudable and yet the end analysis may still leave the question unanswered.

In utero topographic analysis of astrocytes and neuronal cells in the spinal cord of mutant mice with myelomeningocele

OBJECT

Myelomeningocele (MMC) is the most severe form of spina bifida causing severe neurological deficits. Injury to the placode has been attributed to in utero aggression. In this study, glial and neuronal cell changes in both number and topography in mice with MMC were investigated during gestation.

METHODS

The curly tail/loop-tail mice model of MMC was used, and fetuses were harvested using caesarean surgery at Days 14.5, 16.5, and 18.5 (full gestation at 19 days). Immunohistochemical analyses of the MMC placodes and the normal spinal cords from the control group were performed using anti-glial fibrillary acidic protein (astrocytes) and mouse anti-neuronal nuclear (neurons) antibodies. Light microscopy was used along with computer-assisted morphometric evaluation. Progressive increases in astrocytes in the spinal cord of all mouse fetuses were found between Days 14.5 and 18.5 of gestation. This increase was significantly higher in the placodes of mice with MMC than in those of normal mice, particularly in the posterior region. Neuronal labeling at Day 14.5 of gestation was similar between mice with MMC and control mice. At Day 16.5 of gestation there was a deterioration of neural tissue in MMC fetuses, mainly in the posterior region, progressing until the end of gestation with a marked loss of neurons in the entire MMC placode.

CONCLUSIONS

This study delineated the quantitative changes in astrocytes and neurons associated with MMC development during the late stages of gestation. The detailed topographic analysis of the MMC defines the timing of the intrauterine insult and how the placode lesions progress. This study supports the current concept of placode protection through in utero surgery for fetuses with MMC.

Fetal spina bifida in a mouse model: loss of neural function in utero

OBJECT

The devastating neurological deficit associated with myelomeningocele has previously been assumed to be a direct and inevitable consequence of the primary malformation-failure of neural tube closure. An alternative view is that secondary damage to the pathologically exposed spinal cord tissue in utero is responsible for the neurological deficiency. If the latter mechanism were shown to be correct, it would provide an objective rationale for the performance of in utero surgery for myelomeningocele, because coverage of the exposed spinal cord could be expected to alleviate or perhaps prevent neurodegeneration. To examine this question, the authors studied the development of neuronal connections and neurological function of mice during fetal and neonatal stages in a genetic model of exposed lumbosacral spina bifida.

METHODS

The persistently exposed spinal cord of mouse fetuses carrying both curly tail and loop-tail mutations exhibited essentially normal anatomical and functional hallmarks of development during early gestation (embryonic Days 13.5-16.5), including sensory and motor projections to and from the cord. A significant proportion of fetuses with spina bifida at early gestation exhibited sensorimotor function identical to that seen in age-matched healthy controls. However, at later gestational stages, increasing neurodegeneration within the spina bifida lesion was detected, which was paralleled by a progressive loss of neurological function.

CONCLUSIONS

These findings provide support for the hypothesis that neurological deficit in human myelomeningocele arises following secondary neural tissue destruction and loss of function during pregnancy.

Current diagnosis and management of fetal genitourinary abnormalities

Prenatal assessment with ultrasonography provides excellent imaging of fluid-filled structures (eg, hydronephrosis, renal cysts, and dilated bladder) and renal parenchyma. This information allows for the generation of a differential diagnosis, identification of associated anomalies, and assessment of the prenatal and postnatal risks of a given anomaly. This enhances parental education and prenatal and postnatal planning. This article discusses the current methods of diagnosis and management of fetal genitourinary anomalies, and also the postnatal evaluation and treatment of these conditions.

Bladder and External Urethral Sphincter Function After Prenatal Closure of Myelomeningocele

PURPOSE

We compared urodynamic findings in patients who underwent prenatal closure of myelomeningocele with those of patients who underwent postnatal closure, and equivalent lower urinary tract evaluations.

MATERIALS AND METHODS

Urodynamic studies of 5 patients (2 boys, 3 girls) who underwent prenatal closure of myelomeningocele were compared to those of 88 patients with similar level lesions who underwent repair postnatally between 1979 and 2002.

RESULTS

All 5 patients in the prenatally treated cohort had lower lumbosacral lesions on neurological examination. These patients displayed no evidence of electromyographic activity, indicating complete denervation of the external sphincter. In comparison 34 of the 88 patients in the postnatal cohort (39%) lacked sphincter activity at newborn examination, with similar findings noted at 1-year evaluation. In terms of bladder function all 5 patients in the prenatal cohort exhibited detrusor overactivity, compared to 33 of the 88 patients (38%) in the postnatal cohort at the newborn examination, with similar findings at 1-year evaluation.

CONCLUSIONS

Fetal closure of myelomeningocele is associated with a higher incidence of complete denervation of the external urethral sphincter and detrusor overactivity compared to postnatal closure. Patients who undergo this novel procedure should undergo urodynamic studies in the immediate newborn period and should be under close postnatal surveillance to document possible tethering of the spinal cord, urinary incontinence and increased detrusor pressures.

The Timing of Primary Neurosurgical Repair Significantly Affects Neurogenic Bladder Prognosis in Children With Myelomeningocele

PURPOSE

The correlation between timing of the primary neurosurgical repair and urological prognosis in infants with open spinal dysraphism remains unknown. We investigated the impact of primary repair timing on neurogenic bladder prognosis in children with myelomeningocele.

MATERIALS AND METHODS

We retrospectively reviewed the records of 401 children with myelomeningocele followed at our multidisciplinary clinic between 1996 and 2005. Among these patients 129 were included in the study based on the availability of urological followup data at age 3 years, which was chosen as an ideal point for the standardization of urological findings. Children were assigned to 1 of 2 groups-those who underwent primary neurosurgical repair within 72 hours of delivery (group 1) and those undergoing repair after 72 hours (group 2). We compared the incidence of febrile urinary tract infections, hydronephrosis, vesicoureteral reflux and secondary tethering of the spinal cord at age 3 years, as well as cystometric bladder capacity and detrusor leak point pressure between the 2 groups.

RESULTS

Urological followup data at age 3 years revealed significantly increased incidence of febrile urinary tract infections, vesicoureteral reflux, hydronephrosis and secondary tethering of the spinal cord in children in group 2 compared to group 1 (chi-square, p < or =0.05 for all comparisons). Urodynamic assessment also showed a significantly lower bladder capacity and a substantially higher detrusor leak point pressure in children who received primary repair at later than 72 hours (t test, p <0.05). A subgroup analysis of group 1 comparing children who underwent repair before and after 24 hours following delivery failed to demonstrate any significant difference in terms of febrile urinary tract infections, vesicoureteral reflux, hydronephrosis and secondary tethering (chi-square, p >0.05 for all comparisons), whereas mean bladder capacity was significantly higher (t test, p <0.05) and mean detrusor leak point pressure was lower (t test, p = 0.08) in children undergoing repair within 24 hours of delivery.

CONCLUSIONS

The timing of primary neurosurgical repair has a significant impact on neurogenic bladder prognosis in children with myelomeningocele. Closure of the spinal lesion on the first day of life seems to provide the best chance for favorable lower urinary tract function.

Fetal anal incontinence evaluated by amniotic fluid digestive enzyme assay in myelomeningocele spina bifida

The goals of this study were to determine whether anal sphincter dysfunction in spina bifida develops during fetal life or after birth and whether it reflects the severity of spina bifida and therefore can be used as a criterion to select the cases that could benefit from in uterosurgery. Total protein and digestive enzyme activities [gamma-glutamyl transpeptidase (GGTP), aminopeptidase M (AMP), and alkaline phosphatase isoenzymes including the intestinal form (iALP)] were assayed retrospectively in amniotic fluid from 80 myelomeningocele spina bifida cases without unrelated associated malformation (gestational age 14-33 wk). A normal enzyme activity profile was observed in 46 of the 80 cases. Two abnormal profiles were observed: 1) bilious vomiting, characterized by abnormally high GGTP and AMP activities but normal iALP, and 2) digestive enzyme leakage, characterized by abnormally high activities of GGTP, AMP, and iALP, typical of anal incontinence. No relation was observed between these enzyme activity profiles and the different secondary signs of spina bifida or the level of the damage. In conclusion, anal sphincter dysfunction in spina bifida revealed by amniotic fluid digestive enzyme activities occurred before 24 wk in fetal life in 28.7% of cases. This criterion may be indicative of the severity of spina bifida and therefore perhaps could be used to select cases that are suited to in utero surgery. It could also be used to establish the potential benefit of this surgery in fecal incontinence.

Spina bifida

Spina bifida results from failure of fusion of the caudal neural tube, and is one of the most common malformations of human structure. The causes of this disorder are heterogeneous and include chromosome abnormalities, single gene disorders, and teratogenic exposures. However, the cause is not known in most cases. Up to 70% of spina bifida cases can be prevented by maternal, periconceptional folic acid supplementation. The mechanism underlying this protective effect is unknown, but it is likely to include genes that regulate folate transport and metabolism. Individuals with spina bifida need both surgical and medical management. Although surgical closure of the malformation is generally done in the neonatal period, a randomised clinical trial to assess in utero closure of spina bifida has been initiated in the USA. Medical management is a lifelong necessity for individuals with spina bifida, and should be provided by a multidisciplinary team.

Prenatal management of urogenital disorders

Antenatal sonography has increased the detection of urogenital anomalies markedly, including conditions that lead to significant morbidity and mortality. Prenatal intervention is feasible to arrest and sometimes reverse the sequelae of bladder-outlet obstruction, but not necessarily renal damage. Myelomeningoceles, the most severe form of spina bifida,can be corrected in utero, with improvements in hydrocephalus and a decreased incidence of ventricular shunting postnatally. Medical therapy to prevent virilization associated with congenital adrenal hyperplasia has been successful, with improved ability to detect its presence prenatally. As techniques evolve to correct underlying disease processes,it becomes important to assess the therapies critically, particularly with long-term outcome data.

Fetoscopic surgery: where are we today?

PURPOSE OF REVIEW

Since the early 1990s, advances in endoscopic equipment and the commercial availability of micro-catheters, mini-balloons, tiny laser fibers and other ingenious tools have set the trend toward the development of minimally invasive fetoscopic surgical techniques for the treatment of some congenital malformations that progress in severity over the course of gestation and may destroy entire organ systems of the unborn. The purpose of this review is to provide a state-of-the-art overview of these new procedures for the anesthesiologist.

RECENT FINDINGS

Procedures like diagnostic fetoscopies, laser coagulation of inter-twin placental vascular connections in twin-twin transfusion syndrome, fetal tracheal balloon occlusion in diaphragmatic hernia, laser perforation of posterior urethral valves, vocal cord division in congenital high-airway obstruction syndrome and most recently even coverage of spina bifida aperta can be performed entirely percutaneously using minimally invasive fetoscopic techniques. Careful selection of anesthetic methods and intensive maternal monitoring by the anesthesiology team are paramount to the success of these procedures, particularly in hemodynamically unstable fetuses or procedures that employ gas insufflation of the amniotic cavity.

SUMMARY

An increasing spectrum of congenital malformations can be treated by fetoscopic surgery. Compared to open fetal surgery, fetoscopic surgery results in significantly less maternal trauma. Like the open procedures, the efficacy of the fetoscopic procedures to improve fetal outcome over postnatal treatment strategies will have to be assessed in further studies under close supervision of committees for human research.

Evaluation of femur length during the second and third trimesters in fetuses with myelomeningocele

OBJECTIVES

To determine if the femur length of fetuses with myelomeningocele is shorter in the second and third trimesters compared with that of normal fetuses.

METHODS

We retrospectively collected measurements of femur length, head circumference, biparietal diameter and abdominal circumference from detailed obstetric ultrasound studies performed during the second and third trimesters in 31 fetuses with myelomeningocele and 43 fetuses with no detectable anomaly. The gestational age predicted by each parameter (based on Hadlock's tables) was compared with the true gestational age (based on last menstrual period), using the ANCOVA test to determine if there was a statistically significant difference between the two groups of fetuses.

RESULTS

There was no significant difference in femur length (P = 0.60) or in abdominal circumference (P = 0.85) between fetuses with myelomeningocele and normal fetuses. Fetuses with myelomeningocele did have a significantly lower biparietal diameter and head circumference (P < or = 0.001).

CONCLUSIONS

Myelomeningocele is not associated with reduced femur length in the second and third trimesters, suggesting that the known postnatal lower extremity foreshortening in patients with myelomeningocele develops late in gestation or after birth.

Maternal-fetal research and human research protections policy

It may be that the current system of formal definitions, ethical theories, and voluntary professional guidelines to protect patients from unwittingly becoming subjects of research is inadequate to meet the challenge of surgical innovation. Important questions, such as when surgical innovation becomes research involving human subjects or how to distinguish between variations on an existing technique and true innovations, are key. These questions also apply to MFS as an innovative surgical therapy. Now that MFS has been recognized as experimental and formal clinical trials will be conducted, it is important to ensure adequate protection of the pregnant women and fetuses involved as human research subjects. This issue is even more pertinent in light of the new regulations regarding fetuses as research subjects. Those responsible for reviewing study protocols will have to be especially careful when examining the new version of DHHS regulations as they apply to future studies in the field of MFS.

Maternal-fetal surgery for treatment of myelomeningocele

Maternal-fetal surgery for repair of fetal MMC is experimental treatment for which ethically justified clinical trials are not yet possible because equipoise is not established on medical or nonmedical grounds. We have focused here on only two of the important questions raised by this surgery. At least three others might have been considered. First is the question of access to the surgery. MMC is available only to those who can afford it. Given its poor results, that may be a good thing. However, if it were ever proved successful, it should be covered for the poor and affluent women who desire it. Second is the question of the autonomy of the women who seek the procedure. Although the women who undergo the surgery at Vanderbilt are counseled extensively by bioethicists, the autonomy of their decisions may be compromised by pressures from partners or others who think that any risk for the sake of a potential child is fully warranted. Third is the issue of potential discrimination against people with disabilities. Seeking or providing surgery that introduces the risk of fetal demise, a risk that could be avoided by postponing the surgery until after birth, suggests that life with disability is regarded as worse than death. Each of these questions deserves careful, critical analysis in its own right. Along with those addressed in this article, these issues are applicable to other ethical issues in perinatology, including those examined by other contributors to this issue.

Primary myelomeningocele closure and consequences

PURPOSE OF REVIEW

Myelomeningocele, the most frequently occurring open neural tube defect, requires lifelong care of the patient by medical professionals and by relatives. A basic understanding of the neurosurgical measures that have to be taken in the newborn, the infant, the child and the adult is important also for physicians of other disciplines involved in the treatment of patients with myelomeningocele.

RECENT FINDINGS

The most recent topic broadly discussed in this context is the role of foetal neurosurgery for closure of the neural tube defect. There is ongoing debate as to whether the beneficial postnatal effects of a prenatal operation in the unborn foetus outweighs the possible complications for the mother as well as the child.

SUMMARY

As some of the problems associated with myelomeningocele occur only later in life, it will still take many years until the beneficial, as well as the adverse, effects of prenatal neurosurgical procedures can be evaluated.