Complex gastroschisis: a new indication for fetal surgery?

Gastroschisis (GS) is a congenital abdominal wall defect, in which the bowel eviscerates from the abdominal cavity. It is a non-lethal isolated anomaly and its pathogenesis is hypothesized to occur as a result of two hits: primary rupture of the ‘physiological’ umbilical hernia (congenital anomaly) followed by progressive damage of the eviscerated bowel (secondary injury). The second hit is thought to be caused by a combination of mesenteric ischemia from constriction in the abdominal wall defect and prolonged amniotic fluid exposure with resultant inflammatory damage, which eventually leads to bowel dysfunction and complications. GS can be classified as either simple or complex, with the latter being complicated by a combination of intestinal atresia, stenosis, perforation, volvulus and/or necrosis. Complex GS requires multiple neonatal surgeries and is associated with significantly greater postnatal morbidity and mortality than is simple GS. The intrauterine reduction of the eviscerated bowel before irreversible damage occurs and subsequent defect closure may diminish or potentially prevent the bowel damage and other fetal and neonatal complications associated with this condition. Serial prenatal amnioexchange has been studied in cases with GS as a potential intervention but never adopted because of its unproven benefit in terms of survival and bowel and lung function. We believe that recent advances in prenatal diagnosis and fetoscopic surgery justify reconsideration of the antenatal management of complex GS under the rubric of the criteria for fetal surgery established by the International Fetal Medicine and Surgery Society (IFMSS). Herein, we discuss how conditions for fetoscopic repair of complex GS might be favorable according to the IFMSS criteria, including an established natural history, an accurate prenatal diagnosis, absence of fully effective perinatal treatment due to prolonged need for neonatal intensive care, experimental evidence for fetoscopic repair and maternal and fetal safety of fetoscopy in expert fetal centers. Finally, we propose a research agenda that will help overcome barriers to progress and provide a pathway toward clinical implementation. © 2021 International Society of Ultrasound in Obstetrics and Gynecology

Cortical Surface Matching of the Fetal Brain Pre and Post Fetal Surgery for Open Spina Bifida

Introduction: Fetal surgery has become a clinical reality, even for non-lethal conditions such as open spina bifidayelomeningocele, the spinal cord extrudes into a cereberospinal fluid (CSF) filled sac 1, 2. It is associated with brain anomalies such as hindbrain herniation and variable degrees of ventriculomegaly. Prenatalrepair yields better outcomes compared to postnatal surgery3. Nonetheless, mechanical tissue damage of brain parenchyma due to ventriculomegaly and damage to the neural tracts lead to abnormal white matter development, as demonstrated by diffusion weighted imaging studies4-9. This may lead to altered gyrification patterns in MMC patients. Gyrification, measured by magnetic resonance imaging (MRI), correlates with motor and cognitive function in infants, children and adolescents with who have undergone postnatal closure 6. Evaluation of cognitiveand motor function in fetuses who have had prenatal surgery, is performed only after birth, with deficits becoming more evident with increasing age. Clinicians therefore urgently need early fetal brain imaging methods that can predict the cognitive and motor challenges that fetuses may encounter after birth. We aim to demonstrate that longitudinal quantitative MRI measurement of cortical gyrification is possible, before and after repair. We will also demonstrate the curvature (curvedness and shape index) of cerebellum and ventricles before and after surgery. Methods: T2-weighted single-shot fast spin-echo (SSFSE) was performed of the fetal brain in multiple containing an axial, coronal and sagittal planewith 3mm slice thicknesson women with , both before surgery (n=12, 23+6 1+7 weeks, (22+1–25+6)) and after surgery (n=12, 26+1 1+3 weeks, (24+1– 29+4))acquisition time thirty-forty minutes. Initial diagnosis of open spina bifida was made on mid-trimester ultrasound. Fetuses affected by aneuploidy or with structural anomalies outside the CNS were excluded. A novel automated super resolution reconstruction (SRR) algorithm10, 11 was used to build 3D volumes of the fetal brain based on the 2D stacks that were acquired in different directions. Rigid slice-to-volume registration correcting for fetal motion was used to generate an SRR image in standard anatomical orientation, from which we automatically segmented white matter, ventricles, and cerebellum using template brain segmentations12, 13. 14make us of 12Brain masks for pre-operative SRR volumes were resampled from their corresponding post-operative MMC masks after affine and non-rigid alignment. All masks where manually corrected and meshes were generated using ITK-Snap14. A rigid coherent point drift algorithm was applied to find an initial correspondence for the intrasubject cortical, cerebellar and ventricle regions before and after surgery. Joint spectral matching (JSM) was then used to find the correspondence for the intrasubject at those two different time points. In JSM a dual layered graph was produced whereby layers correspond to the surface of the white matter, cerebellum or ventricles of each subject. The correspondence links from the initial intrasubject matching, connecting both layers to produce a set of shared eigenmodes of the surfaces. After mapping the post-operative surface to the pre-operative surface using JSM, we computed the change in parameters at the vertex of each mesh to explore longitudinal cortical gyrification, and curvature (curvedness and shape index) of the 12. Results: Figure 1 illustrates five spectral modes for the white matter, ventricles and cerebellum of a fetus before surgery (24 weeks), and therafter (26 weeks). Although the meshes are quite different in the three-dimensional space, with respect to different levels of folding, variation in shape, surface area and volume, they have similar representations in the spectral domain. Figure 2 shows the curvedness and shape index in the white matter, cerebellum and ventricles before and after fetal surgery. JSM allows us to map the mean curvatures of each mesh to compute changes in the mean and to generate the shape index.Figure 3 shows maps of mean curvature of a fetus pre and post-surgery. Positive values are depicted in red/yellow and represent gyri (convex structures), and negative values in blue represent sulci (concave) structures. JSM allows mapping of mean curvatures from the post-op to the pre-op space, computing the changes in mean curvature between these two time points in the pre-op space.Figure 4 illustrates the shape index histogram for white matter, showing the differences in gyri and sulci between the pre and post-operative MMC brain.Discussion: Surface-based matching provides additional information about changes in growth and gyrification of the fetal brain compared to measurement of total volume and shape change. This may be useful in evaluating changes in cerebral growth of MMC fetuses before and after fetal surgery. Spectral graph matching is a promising tool for matching shapes with significant differences in cortical folding, surface area, and volume, but with similar representations in the spectral domain such as depicted with fetuses before and after surgery12, 15. Future work may be able to better explore the physiological and mechanical properties contributing to the differences observed in brain growth and development in the context of fetal surgery. Conclusion: Novel analysis of fetal longitudinal correspondence of white matter, and development of specific regions of the brain as secondary gyri emerges, in the context of fetal surgery is demonstrated. This tool allows the measurement of the shape and growth of the white matter surface may help establish longitudinal growth trajectories. References: 1. Rethmann, C., et al., Evolution of posterior fossa and brain morphology after in utero repair of open neural tube defects assessed by MRI. Eur Radiol, 2017. 27(11): p. 4571-4580. 2. Zarutskie, A., et al., Prenatal brain imaging for predicting need for postnatal hydrocephalus treatment in fetuses that had neural tube defect repair in utero. Ultrasound Obstet Gynecol, 2019. 53(3): p. 324-334. 3. Adzick, N.S.T., E.A.; Spong, C. Y.; Brock III, J. W.; Burrows, P. K.; Johnson, M. P.; Howell, R. N.; Farrell, J. N.; Dabrowiak, M.E.; Sutton, L.N.; Gupta, N.; Tulipan, N.B.; D’Alton, M.E.; Farmer, D.L., A Randomised Trial of Prenatal versus Postnatal Repair of Myelomeningocele. N Engl J Med, 2011. 364: p. 993-1004. 4. Juranek, J., et al., Neocortical reorganization in spina bifida. Neuroimage, 2008. 40(4): p. 1516-22. 5. Juranek, J. and M.S. Salman, Anomalous development of brain structure and function in spina bifida myelomeningocele. Developmental Disabilities Research Reviews, 2010. 16(1): p. 23-30. 6. Treble, A., et al., Functional significance of atypical cortical organization in spina bifida myelomeningocele: relations of cortical thickness and gyrification with IQ and fine motor dexterity. Cereb Cortex, 2013. 23(10): p. 2357-69. 7. Hasan, K.M., et al., White matter microstructural abnormalities in children with spina bifida myelomeningocele and hydrocephalus: a diffusion tensor tractography study of the association pathways. J Magn Reson Imaging, 2008. 27(4): p. 700-9. 8. Mignone Philpott, C., et al., Diffusion-weighted imaging of the cerebellum in the fetus with Chiari II malformation. AJNR Am J Neuroradiol, 2013. 34(8): p. 1656-60. 9. Woitek, R., et al., Fetal diffusion tensor quantification of brainstem pathology in Chiari II malformation. Eur Radiol, 2016. 26(5): p. 1274-83. 10. Ebner, M., et al., An Automated Localization, Segmentation and Reconstruction Framework for Fetal Brain MRI, in Medical Image Computing and Computer Assisted Intervention – MICCAI 2018. 2018. p. 313-320. 11. Ebner, M., et al., An automated framework for localization, segmentation and super-resolution reconstruction of fetal brain MRI. NeuroImage, 2019. 12. Orasanu, E., et al., Cortical folding of the preterm brain: a longitudinal analysis of extremely preterm born neonates using spectral matching. Brain Behav, 2016. 6(8): p. e00488. 13. Kuklisova-Murgasova, M., et al., A dynamic 4D probabilistic atlas of the developing brain. Neuroimage, 2011. 54(4): p. 2750-63. 14. Yushkevich, P.A., et al., User-guided 3D active contour segmentation of anatomical structures: significantly improved efficiency and reliability. Neuroimage, 2006. 31(3): p. 1116-28. 15. Lomabert, H., Spopring J., and Siddiqi K., Diffeomorphic spectral matching of cortical surafaces. Inf Process Med Imaging, 2013. 7917: p. 376-289

Monochorionic triamniotic triplet pregnancy with a co-triplet fetus discordant for congenital cystic adenomatoid malformation of the lung

BACKGROUND: Spontaneous monochorionic triamniotic pregnancy is rare and is at increased risk for pregnancy complications. The presence of an anomalous fetus further complicates the management. CASE PRESENTATION: We present a case of monochorionic triamniotic triplet pregnancy diagnosed at 15 weeks of gestation with one fetus having developed a multicystic lung lesion, suggestive of congenital cystic adenomatoid malformation (CCAM). At 24 weeks, the largest cyst measured 10 mm in diameter. We managed the pregnancy conservatively and delivered three live male fetuses with birth weights 1560 g, 1580 g and 1590 g at 35 weeks of gestation. Two newborns were admitted to the neonatal intensive care unit with respiratory distress, the third one died due to sepsis 7 days postpartum. One of the newborns was discharged healthy at 24 days postpartum. The newborn with CCAM developed a pneumothorax on the right side, recovered after treatment, and was discharged after one month. Computerized tomography (CT) of the infant at 3 months demonstrated two cystic lesions in the middle lobe of the right lung measuring 25 mm and 15 mm. A repeat CT of the infant at 6 months showed a 30 mm solitary cystic mass. CONCLUSION: Monochorionic triamniotic triplet pregnancy with a co-triplet fetus discordant for CCAM, present rarely and can be managed conservatively. These findings may help in decision making and counselling of parents

Prenatal use of salbutamol in congenital total atrioventricular block

This article describes a fetal presentation at 24 weeks and 5 days postmenstrual age of a congenital complete AV block in the context of maternal lupus (anti-SSA antibodies). Because of fetal hydrops in decreasing heart rate (56 beats/min), salbutamol was started successfully as a sympathomimetic in combination with corticosteroids, with increase in the fetal heart rate and fetal hydrops. A caesarean section was performed at 31 weeks and 4 days because of increasing pleural effusion. Postnatal policy consisted of placement of temporary epicardial pacemaker leads and implantation of an internal pacemaker after 6 weeks.status: publishe