Intrauterine Myelomeningocele Repair: Effect on Short-Term Complications of Prematurity

The Management of Myelomeningocele Study: Short-Term Neonatal Outcomes

INTRODUCTION

The Management of Myelomeningocele Study was a multicenter randomized trial to compare prenatal and standard postnatal repair of myelomeningocele (MMC). Neonatal outcome data for 158 of the 183 randomized women were published in The New England Journal of Medicine in 2011.

OBJECTIVE

Neonatal outcomes for the complete trial cohort (N = 183) are presented outlining the similarities with the original report and describing the impact of gestational age as a mediator.

METHODS

Gestational age, neonatal characteristics at delivery, and outcomes including common complications of prematurity were assessed.

RESULTS

Analysis of the complete cohort confirmed the initial findings that prenatal surgery was associated with an increased risk for earlier gestational age at birth. Delivery occurred before 30 weeks of gestation in 11% of neonates that had fetal MMC repair. Adverse pulmonary sequelae were rare in the prenatal surgery group despite an increased rate of oligohydramnios. There was no significant difference in other complications of prematurity including patent ductus arteriosus, sepsis, necrotizing enterocolitis, periventricular leukomalacia, and intraventricular hemorrhage.

CONCLUSION

The benefits of prenatal surgery outweigh the complications of prematurity.

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.

Morbidity and cost burden of prenatal myelomeningocele repair

OBJECTIVE

This study compared the morbidities and financial burden associated with prenatal open myelomeningocele repair versus postnatal repair.

MATERIALS AND METHODS

The retrospective study cohort included 23 mother-infant dyads undergoing prenatal repair and 30 with postnatal repair. Financial, demographic, and medical information were obtained for mother-infant dyads from each infant's birth through the first year of life.

RESULTS

Infants in the prenatal repair group were significantly affected by sequelae of prematurity, including apnea, bronchopulmonary dysplasia, and retinopathy of prematurity. Importantly, fewer of these infants required ventriculoperitoneal shunt procedures and the overall improved composite outcome of shunting or death. Infants in the postnatal repair group required more hospital readmissions in the first year of life. Financial costs for mother-infant dyads in the prenatal repair group were higher, driven by the length of stay in the neonatal intensive care unit and maternal hospital admissions. Kaplan-Meier curves analyzing the relative contributions of the length of stay and total charges in the population were constructed. The maternal contribution was markedly different between groups due to postoperative hospitalization, readmission, and close fetal surveillance required. Though these differences did not reach statistical significance, it highlights an important burden on families and the medical system.

CONCLUSIONS

This is the first study to report the contributions of prematurity in relation to maternal and infant morbidity and financial costs. The benefits of prenatal myelomeningocele repair include lower risk for ventriculoperitoneal shunting and fewer hospital readmissions. The risk of preterm birth and its neonatal sequelae continue to be a significant burden.

Spinal cord malformations

Malformations of the spinal cord are one of the most frequent malformations. They should be clearly divided into two completely different families of malformations: open dysraphisms and occult dysraphisms. Open dysraphism mostly consists in myelomeningocele (MMC). Its incidence is 1/1000 live births with a wide variation. Folic acid supplementation has been shown to reduce its risk. In most cases, the diagnosis is done prenatally by serum screening and ultrasound and may lead to termination of pregnancy. In case of decision to continue pregnancy, surgical treatment must be achieved during the first days of life, and in 50 to 90% of cases, a ventricular shunt must be installed. The follow-up of these children must be continued throughout life looking for late complications (Chiari II and syringomyelia, vertebral problems, neuropathic bladder, tethered cord). Occult dysraphisms are a heterogeneous group of malformations. Lipomas (filum and conus) are the most frequent and their treatment remains controversial. Diastematomyelia, neurenteric cysts, dermal sinus, and more complex forms (Currarino syndrome) belong to this group. Most of them can and must be diagnosed prenatally or at birth by careful examination of the lower back for the cutaneous stigmata of the disease to decrease the risk of neurological, urological, or orthopedic permanent handicap.

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.

Reproductive outcomes in subsequent pregnancies after a pregnancy complicated by open maternal-fetal surgery (1996-2007)

OBJECTIVE

The reproductive and gynecologic outcomes for women after the pregnancy complicated by open maternal-fetal surgery (OMFS) were evaluated.

STUDY DESIGN

The retrospective review identified 93 women with OMFS from a single institution (1996-2007). Consent and questionnaires were sent to women. Institutional review board approval was obtained from the Committee for Protection of Human Subjects.

RESULTS

The total return rate was 57.3%. Total pregnancies reported were 47, with 36 delivering after 20 weeks' gestation. The uterine dehiscence and rupture rates were 14% and 14%, respectively. Fetal anomalies occurred in 4 subsequent pregnancies. Normal conception occurred in 98% of subsequent pregnancies. Gynecologic issues were reported by 8 women, with infertility, abdominal pain, and ovarian and uterine factors.

CONCLUSION

The reproductive outcomes of uterine dehiscence (14%) and rupture (14%) in a subsequent pregnancy continue to be a major counseling issue for OMFS. Fertility and gynecologic factors do not appear to be increased for women undergoing OMFS.

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.

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.

Reproductive outcomes after pregnancy complicated by maternal-fetal surgery

OBJECTIVE

The reproductive outcomes for women after the pregnancy complicated by maternal-fetal surgery were evaluated to obtain evidence-based information for prenatal risk counseling.

STUDY DESIGN

The retrospective review identified 83 women with maternal-fetal surgery from a single institution (1996-2002). These women were sent a consent form and a questionnaire to document postoperative problems, fertility, obstetric outcomes, and psychosocial concerns in pregnancy after the index fetal therapy. Institutional Review Board approval was obtained from Committee for Protection of Human Subjects.

RESULTS

The total return rate was 55 (66%). The pregnancy rate was 62% (18% spontaneous abortion, 24% preterm delivery, and 58% term delivery). Complications were reported in 12 of 34 pregnancies (35%), including uterine dehiscence/rupture (12%/6%), cesarean hysterectomy (3%), and antepartum hemorrhage requiring transfusion (9%).

CONCLUSION

The reproductive outcome of uterine dehiscence, rupture, and hysterectomy was 12%, 6%, and 3%, respectively, after a pregnancy complicated by maternal-fetal surgery. The uterine rupture rate is similar to the rupture rate after "classical" cesarean section (4%-9%).

Intrauterine myelomeningocele repair

Preliminary studies have suggested that IUMR reduces the incidence of shunt-dependent hydrocephalus and the severity of the Chiari malformation. An RCT is in progress to confirm these results. Future efforts will revolve around refinement of the procedure with the goal of reducing risk. Robot-assisted surgery holds the promise of achieving this goal. If it is successful. IUMR might well become the standard therapy for myelomeningocele, resulting in a significant reduction in the devastating morbidity associated with this disease.