Luc Joyeux

Fetoscopic versus Open Repair for Spina Bifida Aperta: A Systematic Review of Outcomes.

Objective: To compare outcomes of fetoscopic spina bifida aperta repair (FSBAR) with the results of the open approach (OSBAR) as in the Management Of Myelomeningocele Study (MOMS). Methods: This was a systematic comparison of reports on FSBAR with data from the MOMS (n = 78). Inclusion criteria were studies of spina bifida aperta patients who underwent FSBAR and were followed for ≥12 months. Primary outcome was perinatal mortality. Secondary outcomes included operative, maternal, fetal, neonatal and infant outcomes. Results: Out of 16 reports, we included 5 from 2 centers. Due to bias and heterogeneity, analysis was restricted to two overlapping case series (n = 51 and 71). In those, FSBAR was technically different from OSBAR, had comparable perinatal mortality (7.8 vs. 2.6%, p = 0.212) and shunt rate at 12 months (45 vs. 40%, p = 0.619), longer operation time (223 vs. 105 min, p < 0.001), higher preterm prelabor membrane rupture rate (84 vs. 46%, p < 0.001), earlier gestational age at birth (32.9 vs. 34.1 weeks, p = 0.03), higher postnatal reoperation rate (28 vs. 2.56%, p < 0.001) and absence of uterine thinning or dehiscence (0 vs. 36%, p < 0.001). Functional outcomes were not available. Conclusion: FSBAR utilizes a different neurosurgical technique, takes longer to complete, induces more prematurity, requires additional postnatal procedures, yet has a comparable shunt rate and is not associated with uterine thinning or dehiscence. Long-term functional data are awaited.

Sonographic detection of central nervous system defects in the first trimester of pregnancy

The fetal central nervous system can already be examined in the first trimester of pregnancy. Acrania, alobar holoprosencephaly, cephaloceles, and spina bifida can confidently be diagnosed at that stage and should actively be looked for in every fetus undergoing first‐trimester ultrasound. For some other conditions, such as vermian anomalies and agenesis of the corpus callosum, markers have been identified, but the diagnosis can only be confirmed in the second trimester of gestation. For these conditions, data on sensitivity and more importantly specificity and false positives are lacking, and one should therefore be aware not to falsely reassure or scare expecting parents based on first‐trimester findings. This review summarizes the current knowledge of first‐trimester neurosonography in the normal and abnormal fetus and gives an overview of which diseases can be diagnosed.

In Utero Lung Gene Transfer Using Adeno-Associated Viral and Lentiviral Vectors in Mice

Virus-mediated gene transfer to the fetal lung epithelium holds considerable promise for the therapeutic management of prenatally diagnosed, potentially life-threatening inherited lung diseases. In this study we hypothesized that efficient and life-long lung transduction can be achieved by in utero gene therapy, using viral vectors. To facilitate diffuse entry into the lung, viral vector was injected into the amniotic sac of C57BL/6 mice on embryonic day 16 (term, ∼ 20 days) in a volume of 10 μl. Vectors investigated included those based on adeno-associated virus (AAV) (serotypes 5, 6.2, 9, rh.64R1) and vesicular stomatitis virus G glycoprotein (VSV-G)-pseudotyped HIV-1-based lentivirus (LV). All vectors expressed green fluorescent protein (GFP) under the transcriptional control of various promoters including chicken β-actin (CB) or cytomegalovirus (CMV) for AAV and CMV or MND (myeloproliferative sarcoma virus enhancer, negative control region deleted) for LV. Pulmonary GFP gene expression was detected by fluorescence stereoscopic microscopy and immunohistochemistry for up to 9 months after birth. At equivalent vector doses (mean, 12 × 10(10) genome copies per fetus) three AAV vectors resulted in long-term (up to 9 months) pulmonary epithelium transduction. AAV2/6.2 transduced predominantly cells of the conducting airway epithelium, although transduction decreased 2 months after vector delivery. AAV2/9-transduced cells of the alveolar epithelium with a type 1 pneumocyte phenotype for up to 6 months. Although minimal levels of GFP expression were observed with AAV2/5 up to 9 months, the transduced cells immunostained positive for F480 and were retrievable by bronchoalveolar lavage, confirming an alveolar macrophage phenotype. No GFP expression was observed in lung epithelial cells after AAV2/rh.64R1 and VSV-G-LV vector-mediated gene transfer. We conclude that these experiments demonstrate that prenatal lung gene transfer with AAV vectors engineered to target pulmonary epithelial cells may provide sustained long-term levels of transgene expression, supporting the therapeutic potential of prenatal gene transfer for the treatment of congenital lung diseases.

A growing animal model for neonatal repair of large diaphragmatic defects to evaluate patch function and outcome

Objectives We aimed to develop a more representative model for neonatal congenital diaphragmatic hernia repair in a large animal model, by creating a large defect in a fast-growing pup, using functional pulmonary and diaphragmatic read outs. Background Grafts are increasingly used to repair congenital diaphragmatic hernia with the risk of local complications. Growing animal models have been used to test novel materials. Methods 6-week-old rabbits underwent fiberoptic intubation, left subcostal laparotomy and hemi-diaphragmatic excision (either nearly complete (n = 13) or 3*3cm (n = 9)) and primary closure (Gore-Tex patch). Survival was further increased by moving to laryngeal mask airway ventilation (n = 15). Sham operated animals were used as controls (n = 6). Survivors (90 days) underwent chest X-Ray (scoliosis), measurements of maximum transdiaphragmatic pressure and breathing pattern (tidal volume, Pdi). Rates of herniation, lung histology and right hemi-diaphragmatic fiber cross-sectional area was measured. Results Rabbits surviving 90 days doubled their weight. Only one (8%) with a complete defect survived to 90 days. In the 3*3cm defect group all survived to 48 hours, however seven (78%) died later (16–49 days) from respiratory failure secondary to tracheal stricture formation. Use of a laryngeal mask airway doubled 90-day survival, one pup displaying herniation (17%). Cobb angel measurements, breathing pattern, and lung histology were comparable to sham. Under exertion, sham animals increased their maximum transdiaphragmatic pressure 134% compared to a 71% increase in patched animals (p<0.05). Patched animals had a compensatory increase in their right hemi-diaphragmatic fiber cross-sectional area (p<0.0001). Conclusions A primarily patched 3*3cm defect in growing rabbits, under laryngeal mask airway ventilation, enables adequate survival with normal lung function and reduced maximum transdiaphragmatic pressure compared to controls.

A novel translational model for fetoscopic intratracheal delivery of nanoparticles in piglets

The aim of this study was to assess the feasibility of fetal tracheal injection in the late‐gestational pig to target the airways.

Safety and efficacy of fetal surgery techniques to close a spina bifida defect in the fetal lamb model: A systematic review

To determine the safety and efficacy of different neurosurgical techniques for closure of spina bifida (SB) in the fetal lamb model.

Quantitative analysis of motor evoked potentials in the neonatal lamb

Evoking motor potentials are an objective assessment method for neuromotor function, yet this was to our knowledge never done in neonatal lambs. There is neither a method for standardized quantification of motor evoked potentials (MEPs). We first aimed to evaluate the feasibility of MEP recording in neonatal lambs and test its validity. Second we aimed to develop an algorithm for its quantification and test its reliability since manual input is required. We recorded myogenic MEPs after transcranial motor cortex stimulation in 6 lambs aged 1–2 days. MEPs were also measured in one lamb undergoing Neuro-Muscular Blockade (NMB) and another undergoing lumbar spinal cord (SC) transection, both serving as controls. We computed 5 parameters using a custom-made algorithm: motor threshold, latency, area-under-the-curve, peak-to-peak amplitude and duration. Intra- and inter-observer reliability was analyzed. MEPs could be easily recorded, disappearing after NMB and SC transection. The algorithm allowed for analysis, hence physiologic readings of the parameters in all 4 limbs of all lambs were obtained. Our method was shown to have high intra- and inter-observer ( ≥70%) reliability for latency, area-under-the-curve and peak-to-peak amplitude. These results suggest that standardized MEP recording and analysis in neonatal lambs is feasible, and can reliably assess neuromotor function.

Maternal-fetal surgery for myelomeningocele: some thoughts on ethical, legal, and psychological issues in a Western European situation

BackgroundThe results of the Management of Myelomeningocele Study (MOMS) randomized controlled trial have demonstrated that maternal-fetal surgery (MFS) for myelomeningocele (MMC) compared to postnatal MMC repair has clear neurological benefits for the child at 12 and 30 months of age. Level I evidence nevertheless does not provide answers to many questions in this delicate field. Since the beginning of 2012, our fetal center has been offering MFS for spina bifida aperta (SBA) to patients from different European and non-European countries, in a societal context where termination of pregnancy is the option chosen by most patients when being informed of this diagnosis.MethodsWe aim to explore in this text some of the ethical, legal, and psychological issues that we have encountered.ResultsFor many of these questions, we do not have definite answers. A pregnant patient when diagnosed with a MMC fetus is a vulnerable subject. She needs to be referred to a highly specialized center with sufficient expertise in diagnosis and in all therapeutic options. Objective but compassionate counseling is of paramount importance. It is required that a multidisciplinary professional team obtains full voluntary consent from the mother after providing an appropriate information including diagnosis, short-, medium-, and long-term prognosis as well as benefits and harms of the fetal surgery.ConclusionThe latter should be offered with full respect for maternal choice and individual assessment and perception of potential risks taking into consideration legislation in the fetal center and the parents’ country legislation.

Tissuepatch is biocompatible and seals iatrogenic membrane defects in a rabbit model

To evaluate novel sealing techniques for their biocompatibility and sealing capacity of iatrogenic fetal membrane defects in a pregnant rabbit model.

Providing direction improves function: Comparison of a radial pore-orientated acellular collagen scaffold to clinical alternatives in a surgically induced rabbit diaphragmatic tissue defect model

Gore‐Tex® is a widely used durable patch for repair of congenital diaphragmatic defects yet may result in complications. We compared Gore‐Tex with a composite of a radial pore‐orientated collagen scaffold (RP‐Composite) and clinically used porcine small intestinal submucosa (SIS; Surgisis®) in a rabbit model for diaphragmatic hernia. The growing rabbit mimics the rapid rib cage growth and reherniation rates seen in children. We created and immediately repaired left hemidiaphragmatic defects in 6‐week‐old rabbits with Gore‐Tex, SIS, and an RP‐Composite scaffold. An additional group of rabbits had a sham operation. At 90 days, survivors more than doubled in weight. We observed few reherniations or eventrations in Gore‐Tex (17%) and RP‐Composite (22%) implanted animals. However, SIS failed in all rabbits. Maximum transdiaphragmatic pressure was lower in Gore‐Tex (71%) than RP‐Composite implanted animals (112%) or sham (134%). Gore‐Tex repairs were less compliant than RP‐Composite, which behaved as sham diaphragm (p < 0.01). RP‐Composite induced less foreign body giant cell reaction than Gore‐Tex (p < 0.05) with more collagen deposition (p < 0.001), although there was a tendency for the scaffold to calcify. Unlike Gore‐Tex, the compliance of diaphragms reconstructed with RP‐Composite scaffolds were comparable with native diaphragm, whereas reherniation rates and transdiaphragmatic pressure measurements were similar.