Faculty Bibliography

PURPOSE/OBJECTIVE:The use of dexamethasone (Dx) stimulates growth, fetal lung maturation and can improve pulmonary hypertension in congenital diaphragmatic hernia (CDH). Our aim was to evaluate the effect of Dx on the lung after fetal pulmonary ventilation in the CDH rat model. METHODS:Some groups underwent prenatal treatment with dexamethasone (0.4 mg/kg) that was given at 18.5 gestational day (GD). Sprague-Dawley rat fetuses were divided into groups: control (C); ventilated control (CV); control exposed to dexamethasone (CDx); ventilated control exposed to dexamethasone (CVDx); congenital diaphragmatic hernia (CDH), ventilated CDH (CDHV), CDH exposed to dexamethasone (CDHDx) and ventilated CDH exposed to dexamethasone (CDHVDx). At 21.5 GD fetuses were delivered by C-section, weighed and ventilated for 30 min. We analyzed the lung morphometry by Masson's Trichrome stain, and VEGF, VEGFR1, VEGFR2 and NOS3 expression by immunohistochemistry. RESULTS:All fetuses with CDH, with or without prenatal dexamethasone showed lung and body weight lower than control fetuses (p < 0.05). All groups that received dexamethasone showed a decrease in the medial muscular layer of arterioles, the internal diameter of the air spaces (Lma) and length of parenchymal transection/airspace ratio (p < 0.05). In the immunohistochemistry, VEGF decreased more in CDHDV group (p < 0.05). VEGFR1 showed no difference, whereas VEGFR2 decreased significantly in the CDHDV group (p < 0.05). NOS3 increased in the group CDHDV (p < 0.05). CONCLUSION/CONCLUSIONS:The use of prenatal dexamethasone added to ventilation alters the VEGF and NO pathways.

BACKGROUND:This study aimed to assess the feasibility of single-access fetal endoscopy (SAFE) for the management of myelomeningocele (MMC) using intrauterine carbon dioxide as a distension medium in a sheep model. METHODS:This prospective experimental case-control study investigated 12 lamb fetuses that had a myelomeningocele-like defect surgically created on the 75th day of gestation. Four fetuses remained untreated (control group), and eight fetuses had MMC repair using two fetoscopic approaches with carbon dioxide used to distend the amniotic cavity. A collagen patch was placed over the defect and secured with surgical sealant. Four animals had a two-port fetoscopic procedure, and four animals had SAFE. Clinical and pathologic studies were performed after delivery. RESULTS:This study confirmed the validity of the animal MMC model. None of the control animals was able to stand or walk, and all had a significant defect in the lumbar area with continuous leakage of cerebrospinal fluid, ventriculomegaly, and a Chiari-II malformation. All the treated animals, independently of the number of ports used in the repair, were able to walk and had a closed defect with resolution of the Chiari malformation. CONCLUSIONS:The SAFE patch and glue coverage of surgically created fetal MMC is feasible and effective in restoring gross neurologic function in the fetal lamb model.

BACKGROUND:Fetuses with severe congenital diaphragmatic hernia (CDH) and pulmonary hypoplasia may benefit from fetal endoluminal tracheal occlusion (FETO). Enlargement of the main bronchi and trachea appears to be a common complication of FETO. OBJECTIVE:To retrospectively evaluate the trachea and main bronchi of infants who underwent FETO for CDH and compare diameters with age-matched references. MATERIAL AND METHODS/METHODS:Postnatal and follow-up chest radiographs were performed in seven children with unilateral CDH treated by FETO. Additional CT was performed in six of these (one neonate died before CT could be performed). Images were acquired from 3 days to 23 months of age. For each child, radiographs and CT images with optimal visualisation of the airways were selected for retrospective analysis. Tracheal and bronchial morphology was assessed by two experienced paediatric radiologists, and the diameters of these structures measured and compared with age-matched references. RESULTS:Mean diameters of the trachea and main bronchi were above the age-matched normal range in all patients, regardless of the side of the hernia or the degree of lung hypoplasia. CONCLUSION/CONCLUSIONS:Enlargement of the trachea and main bronchi appears following FETO and persists at least to the age of 5 years.

OBJECTIVES/OBJECTIVE:To describe the outcome of patients with twin-to-twin transfusion syndrome and cervical length ≤ 25 mm, treated with laser and an Arabin cervical pessary. METHODS:Retrospective analysis of a consecutive series of all cases with severe twin-to-twin transfusion syndrome who underwent laser surgery: a group with cervical length above 25 mm (group A) and two groups who had a cervical length of 25 mm or less prior to the procedure. The first 8 cases (group B) were managed expectantly and the next 8 cases had a cervical pessary inserted immediately after laser surgery (group C). Gestational age at birth was the primary outcome. The secondary outcome was a composite one encompassing severe neonatal morbidity. RESULTS:The median gestational age at laser surgery was 20 weeks in all groups but the median gestational age at delivery was significantly higher in group C versus B (28 vs 32 weeks, p = 0.01). Severe neonatal morbidity was present in 18% in group C and 70% in group B (p < 0.01). CONCLUSION/CONCLUSIONS:Early results suggest a potential role for pessary use in prolonging gestation in cases with shortened cervix at the time of laser. A randomized trial to test this hypothesis should be performed.

PURPOSE/OBJECTIVE:The purpose of this study is to describe the malformations of cortical development detected in a model of cerebrospinal fluid (CSF) leakage and the influence of surgical closure technique on developmental outcome. METHODS:Using a surgically induced model of myelomeningocele (MMC) in sheep, we studied the effects of different repair methods upon the development of hydrocephalus, the presence of the Arnold-Chiari II (AC-II) hindbrain malformation, and cerebral cortex developmental anomalies using gross and histologic (hematoxylin and eosin and Nissl staining) study techniques. RESULTS:A malformed cerebral cortex, including 2 anomalous cortical folding patterns, and lower brain weights were observed in the untreated animals. Hydrocephalus and AC-II malformations were also found in this group. These malformations were mostly prevented with prenatal 2-layer closure. CONCLUSIONS:Cerebral cortical malformations and hydrocephalus, in addition to the AC-II hindbrain malformation, are disorders caused by fetal CSF leakage. These malformations were prevented with the technique of MMC closure currently used in humans. Both observations magnify the importance of the second hit associated with chronic CSF leakage, in addition to the primary defect causing the MMC, in the development of the malformation complex.

OBJECTIVE:Assess the feasibility of a fetoscopic patch coverage method for myelomeningocele repair in a sheep model. STUDY DESIGN/METHODS:Experimental study. A myelomeningocele-like defect was created in 15 fetal sheep on day 75 of gestation. Six remained untreated, whereas 9 underwent fetoscopic coverage of the defect on day 95 of gestation using an inert patch secured with surgical sealant. Clinical and histological examinations were performed after delivery. RESULTS:Four valid newborn lambs were obtained in each group. Mean fetoscopic surgical time was 26.9 (SD=7.4)min. All untreated animals had an open lumbar defect with cerebrospinal fluid leakage, paraplegia, urinary incontinence, and Chiari malformation. All treated animals had a closed defect and were able to walk; one had weak bladder control, and another mild Chiari malformation. CONCLUSION/CONCLUSIONS:In a chronic myelomeningocele model in fetal sheep, fetoscopic repair using a sealed patch results in simple, fast, satisfactory neural tube closure and averts neurological damage and Chiari malformation.

BACKGROUND:Prenatal ultrasound study allows the detection of fetal malformations. Intrauterine interventions are now contemplated to correct, or interfere with, the natural history of these anomalies. Minimally invasive techniques, such as the so-called "Fetendo" (fetal endoscopy), are now therapeutic possibilities. METHODS:From 2002 to 2007, 205 fetoscopies were performed in our hospital's fetal surgery program. Fetoscopic interventions were carried out under epidural anesthesia, accessing the uterine cavity with a fetoscope containing a 1.2-mm telescope. Following ultrasound-guided needle puncture of the amniotic cavity, the fetoscope was inserted through a 3-mm sheath by the Seldinger technique. Visibility was maintained with an amnioinfusion system. This procedure offers access to the placental surface, umbilical cord, and fetus. RESULTS:Fetoscopy was used to perform laser coagulation of communicant placental vessels in 148 biamniotic monochorionic gestations with twin-to-twin transfusion syndrome (TTTS) and to occlude the umbilical cord in 32 cases of discordant monochorionic twins with a severe or lethal anomaly in one of the fetuses, and 5 cases of reversed arterial perfusion (TRAP) sequence. In addition, fetoscopy was performed in 18 cases to treat severe congenital diaphragmatic hernia by tracheal occlusion with an endotracheal balloon. Finally, in 2 cases, fetoscopic release of amniotic bands was performed to rescue extremities and the umbilical cord. The most common complications (10%) were preterm rupture of membranes, which resulted in preterm delivery. Other indications for fetoscopy, which we are currently using in experimental animal models, include low urinary tract obstruction, sacrococcygeal teratoma, and repair of myelomeningocele defects. CONCLUSIONS:Fetoscopy can lower the incidence of preterm labor that occurs in response to the aggression of open surgery. At present, fetoscopy is effective for treating several fetal anomalies. Preterm rupture of membranes remains the weak link of fetoscopy. Refinement of the technique and technologic advances will help this problem and allow the use of fetoscopy for other pathologies in the future.

Mdx mice show a milder phenotype than Duchenne patients despite bearing an analogous genetic defect. Our aim was to sort out genes, differentially expressed during the evolution of skeletal muscle mdx mouse disease, to elucidate the mechanisms by which these animals overcome the lack of dystrophin. Genome-wide microarray-based gene expression analysis was carried out at 3 wk and 1.5 and 3 mo of life. Candidate genes were selected by comparing: 1) mdx vs. controls at each point in time, and 2) mdx mice and 3) control mice among the three points in time. The first analysis showed a strong upregulation (96%) of inflammation-related genes and in >75% of genes related to cell adhesion, muscle structure/regeneration, and extracellular matrix remodeling during mdx disease evolution. Lgals3, Postn, Ctss, and Sln genes showed the strongest variations. The analysis performed among points in time demonstrated significant changes in Ecm1, Spon1, Thbs1, Csrp3, Myo10, Pde4b, and Adamts-5 exclusively during mdx mice lifespan. RT-PCR analysis of Postn, Sln, Ctss, Thbs1, Ecm1, and Adamts-5 expression from 3 wk to 9 mo, confirmed microarray data and demonstrated variations beyond 3 mo of age. A high-confidence functional network analysis demonstrated a strong relationship between them and showed two main subnetworks, having Dmd-Utrn-Myo10 and Adamts5-Thbs1-Spon1-Postn as principal nodes, which are functionally linked to Abca1, Actn4, Crebbp, Csrp3, Lama1, Lama3, Mical2, Mical3, Myf6, Pxn, and Sparc genes. Candidate genes may participate in the decline of muscle necrosis in mdx mice and could be considered potential therapeutic targets for Duchenne patients.

With the advent of less-invasive fetal surgery techniques, nonlethal disorders are considered amenable to intrauterine treatment. Extremity amniotic band syndrome fulfils the criteria of intrauterine disorders conformable with fetal treatment: capability of prenatal diagnosis and severity. We report 2 cases of extremity amniotic bands with risk of limb amputation released fetoscopically with YAG laser.

Congenital intracranial tumours are uncommon and differ from those occurring in older children in clinical presentation, imaging characteristics and prognosis. These tumours are often detected incidentally on routine prenatal US and/or fetal MRI. Hence, the paediatric radiologist should be familiar with the features of those lesions that should be included in the differential diagnosis. In general, the prognosis of these conditions is poor owing to large tumour size and the limitations of adjuvant therapy at such a young age. Congenital lesions involving the head and neck region require a meticulous imaging approach using both US and MRI techniques to better guide prenatal planning and fetal or neonatal surgical procedures.