Prenatal Repair of Spina Bifida: A 2-Center Experience with Open Intrauterine Neurosurgery in Chile.

OBJECTIVE: To report the experience with prenatal repair of open spina bifida (OSB) from 2 centers in Chile. METHODS: Women with a second-trimester fetus with OSB were offered intrauterine neurosurgical repair following the protocol from the Management of Myelomeningocele Study (MOMS) trial. Pediatric follow-up with infants reaching 12 and 30 months of life was also reviewed. RESULTS: Fifty-eight fetuses with OSB underwent intrauterine repair at an average (±SD) gestational age of 24.8 ± 0.9 weeks. There were 3 (5.1%) intrauterine deaths. The average gestational age at delivery of the remaining 55 cases was 33.3 ± 3.6 weeks, and the average birth weight was 2,172 ± 751 g. Delivery before 30 weeks occurred in 11 cases (20.0%). Two (3.6%) neonatal deaths (<28 days) occurred. At 12 months, a ventriculoperitoneal shunt or an endoscopic third ventriculostomy was required in 25% of the cases. At 30 months, 72.4% of the infants were able to walk. DISCUSSION: Prenatal neurosurgical repair of OSB is a complex and challenging intervention. Major complications include perinatal death and severe prematurity. No major maternal complications occurred in our series. A reduction in the need for cerebrospinal fluid diversion and an improved ability to walk seem to be the greatest long-term advantages of this procedure.

Prenatal diagnosis of spina bifida: from intracranial translucency to intrauterine surgery.

Accurate and timely prenatal diagnosis of spina bifida (SB) is a major goal of modern antenatal care. Prenatal screening for open SB should be first performed at the time of routine first-trimester ultrasound by examining the posterior fossa for obliteration or non-visualization of the fourth ventricle ("intracranial translucency") and cisterna magna. The second step of screening is the second-trimester anatomy scan, at which time the features of the Chiari type II malformation should be looked for, including ventriculomegaly, scalloping of the frontal bones ("lemon" sign), and backward and caudal displacement of the cerebellar vermis with obliteration of the cisterna magna ("banana" sign). In cases with positive findings, evaluation must include a focused examination of the spine for defects. In cases of closed SB and SB occulta, the cranial and posterior fossa features will not be present as they are not associated with leaking of spinal fluid and resultant hindbrain herniation, highlighting the fact that the spine should be examined thoroughly whenever possible during the second-trimester scan. In tertiary fetal medicine centers, two-dimensional and three-dimensional ultrasound allows an accurate determination of the location, type, extent, and upper level of the spinal defect as well as the presence of associated anomalies. Fetal magnetic resonance imaging should be restricted to candidates for intrauterine surgery as part of the preoperative protocol.

Acardiac fetus complicating a triplet pregnancy: management and outcome.

OBJECTIVE: To report our experience with the management of triplet pregnancies complicated by an acardiac fetus. METHODS: During the 5-year period from 2003 to 2008, five cases were identified. The prenatal sonographic findings, antepartum course, antenatal intervention if performed, and perinatal outcome of each case were reviewed. RESULTS: Four pregnancies were spontaneously conceived and one was achieved by in vitro fertilization. Three pregnancies were dichorionic and two were monochorionic, and two acardiac fetuses were part of a monoamniotic set. All cases underwent an early sonographic examination, but the diagnosis was only made in the first trimester in only two cases, as the acardiac fetus was overlooked or inaccurately identified as a dead fetus in the remaining three cases. Early fetal demise before 12 weeks occurred in a case of monochorionic-triamniotic triplets. Percutaneous laser coagulation of the main intra-abdominal vessel was attempted at 17 weeks in two cases, with subsequent delivery after 34 weeks and perinatal survival of three of the four structurally normal fetuses. In the other two pregnancies which were managed expectantly, both were complicated by severe preterm delivery with perinatal survival of three of the four structurally normal fetuses. Overall, there were no survivors in one case, one twin survived in two cases, and two twins survived in the remaining two cases. None of the survivor had neurological sequelae. CONCLUSIONS: The presence of an acardiac fetus in a triplet pregnancy carries a high risk for poor pregnancy outcome, including fetal death and severe preterm labor. Prenatal intervention may be indicated in some cases, but does not prevent fetal death of the pump twin.

Congenital diaphragmatic hernia in a first-trimester ultrasound aneuploidy screening program.

OBJECTIVES: To review our experience with the prenatal detection of congenital diaphragmatic hernia (CDH) in fetuses presenting for ultrasound screening of chromosomal abnormalities in the first trimester. METHODS: As part of our first-trimester ultrasound protocol, fetuses with a crown-rump length between 45 and 84 mm underwent a limited anatomical assessment in conjunction with nuchal translucency thickness measurement and nasal bone assessment. Cases of CDH diagnosed prenatally or after delivery in this population were identified. RESULTS: Among the six cases of CDH detected (prevalence of 1 in 927), the first-trimester ultrasound findings were abnormal in five fetuses (83%), including three with increased nuchal translucency only; one with increased nuchal translucency, an intrathoracic stomach, dextrocardia and a cephalocele; and one with normal nuchal translucency thickness and a small, complex intrathoracic mass later confirmed as the fetal stomach. The diagnosis of CDH was confidently made in the first trimester in one case, in the second trimester in three cases, and after birth in the remaining two cases. CONCLUSION: The diagnosis of CDH in the first trimester is difficult, especially in those cases in which the defect is small or late migration of the abdominal viscera occurs. Therefore, screening for CDH in the first trimester is unlikely to be effective.

Endoscopic laser surgery in severe second-trimester twin-twin transfusion syndrome: a three-year experience from a Latin American center.

OBJECTIVE: In order to assess the outcome of pregnancies complicated by severe second trimester twin-twin transfusion syndrome (TTTS) undergoing treatment with endoscopic laser surgery, we reviewed our experience following the implementation of an institutional fetal surgery program. METHODS: Patients presenting with monochorionic-diamniotic twin pregnancies complicated by severe TTTS before 26 weeks of gestation were offered endoscopic laser surgery to coagulate placental vascular anastomoses. Using regional anesthesia and guided by real-time sonography, anastomoses were identified and selectively coagulated. At the end of the procedure, amniodrainage was performed to restore normal amniotic fluid volume. Follow-up and delivery were carried out at the referring institutions. Six-month follow-up was performed in all cases. RESULTS: During a 3-year period from September 2003 to December 2006, 33 consecutive cases of severe TTTS were operated on at a median gestational age of 21 weeks (range 17-25). Nine (27.3%) cases were classified as stage II, 21 (63.6%) as stage III, and three (9.1%) as stage IV. The placenta was anterior or predominantly anterior in 15 (45.5%) of the cases. Overall, both twins were born alive in 16 (48.5%) cases, only one twin was born alive in 11 (33.3%), and neither was born alive in the remaining six (18.2%). Therefore, 81.8% (27 of 33) of the pregnancies resulted in at least one liveborn infant. Among them, the mean gestational age at delivery was 32 weeks (range 23-38) and the mean birthweight of the liveborn infants was 1591 g (range 350-3800). Thirty-four infants survived the perinatal period, yielding an overall perinatal survival rate of 51.5%, with 75.8% (25 of 33) of the pregnancies resulting in at least one perinatal survivor. All neonatal deaths were associated with extreme prematurity. CONCLUSIONS: This preliminary experience suggests that selective laser coagulation appears to be a good treatment option in cases of monochorionic twin pregnancies complicated by severe TTTS. However, technical skills and adequate equipment are required for implementing a fetal surgery program. Auditing outcomes during the learning curve would help in identifying potential problems.

Three-dimensional power Doppler sonography in the prenatal diagnosis of a true knot of the umbilical cord: value and limitations.

OBJECTIVE: The purpose of this study was to examine the value of 3-dimensional power Doppler sonography in the prenatal diagnosis of a true knot of the umbilical cord. METHODS: Cases in which the diagnosis of a true knot of the umbilical cord was suspected by prenatal 2-dimensional sonography were reviewed. The presumably affected segment of the cord was examined with 3-dimensional power Doppler sonography for further characterization. Confirmation of the prenatal diagnosis was sought by reviewing the delivery records and contacting the referring obstetrician and the patients themselves. RESULTS: Eight consecutive cases were studied. Three-dimensional power Doppler sonography displayed a vascular spatial configuration pattern consistent with a true knot of the umbilical cord in all of them. However, the prenatal diagnosis was confirmed at delivery in only 5 cases (62.5%). Although there were no cases of a false knot mimicking a true knot of the umbilical cord, all incorrect diagnoses in this series were associated with multiple loops of the umbilical cord in the third trimester. CONCLUSIONS: Three-dimensional power Doppler sonography seems to be helpful in determining the presence of a true knot of the umbilical cord in utero, especially in the second trimester. However, this should not be considered a definitive method for the diagnosis because multiple loops of the umbilical cord lying close to each other can generate a sonographic image that can be undistinguishable from a true knot of the umbilical cord prenatally, especially when located in a small pocket of amniotic fluid. Therefore, the presumable diagnosis of a true knot of the umbilical cord in utero should be taken with caution.

Discordant lower urinary tract obstruction in early twin gestations: management and outcome.

OBJECTIVE: To report our experience with the management of twin pregnancies discordant for lower urinary tract obstruction. METHODS: Cases of twin pregnancies discordant for lower urinary tract obstruction were identified from our fetal medicine database. Information on ultrasonographic findings, antenatal course, pregnancy complications, and perinatal outcome was obtained by reviewing medical records or contacting the referring obstetricians. RESULTS: Five twin pregnancies discordant for lower urinary tract obstruction were diagnosed between 11 and 15 weeks of gestation. There were 3 dichorionic and 2 monochorionic pregnancies (1 diamniotic and 1 monoamniotic). The dichorionic pregnancies were managed conservatively, resulting in a pregnancy loss of both twins in 1 case, a single fetal death at 29 weeks in 1 case, and an early neonatal death due to lung hypoplasia of the affected twin in 1 case. On the other hand, both monochorionic twin pregnancies were managed with serial vesicocenteses. In both cases, the prenatal course was complicated, 1 by premature rupture of the membranes and the other by cord entanglement, requiring delivery at 29 and 31 weeks, respectively. Among the 4 continuing pregnancies with complete perinatal outcome, none of the affected twins survived, and the structurally normal twins were delivered between 29 and 36 weeks and discharged from the hospital in good condition. CONCLUSION: Twin pregnancies discordant for lower urinary tract obstruction are at high risk of perinatal death and premature delivery. Prenatal intervention seems not to be associated with an improved perinatal outcome of the affected twin, but it may be beneficial in selected cases to attain viability of the unaffected twin.

Perinatal outcome after prenatal diagnosis of placental chorioangioma.

OBJECTIVE: To review the prenatal complications, management, and perinatal outcome in pregnancies complicated by placental chorioangioma. METHODS: Cases of placental chorioangioma diagnosed prenatally as part of a prospective, multicentric program for fetal diagnosis and therapy were identified. All cases were evaluated with color flow imaging. In the latter part of the study, three-dimensional power Doppler angiography was also used to study the vascular pattern of the tumor. Information on maternal demographics, prenatal sonographic findings, pregnancy complications, antenatal intervention, and perinatal outcome was obtained by reviewing the medical records or contacting the referring obstetricians. RESULTS: In the 5-year period from January 1997 to December 2001, 11 cases of placental chorioangioma were diagnosed prenatally. Nine cases were diagnosed in singleton and two in twin pregnancies. Among the nine cases occurring in singletons, five (56%) were associated with pregnancy complications, including polyhydramnios (n = 3), oligohydramnios (n = 2), fetal growth restriction (n = 2), and nonimmune hydrops (n = 1). Amniodrainage was required in one of these cases, allowing prolongation of pregnancy until term. Four (44%) singletons delivered before 35 weeks. Overall, two fetuses died, including one twin due to complications of twin-twin transfusion syndrome and another with hydrops after alcohol injection into the chorioangioma. In four pregnancies, no prenatal complications were detected in spite of continuous growth and vascularity of the placental mass in three of them. CONCLUSION: Placental chorioangioma is associated with an increased risk of pregnancy complications, the most common being polyhydramnios and preterm delivery. In selected cases, amniodrainage allows continuation of the pregnancy with improving perinatal outcome. Fetuses who develop hydrops are at the highest risk for perinatal death, with limited therapeutic options being available. Close follow-up is advised, even in those cases with no associated findings at the time of the diagnosis.