REGRESSION OF MICROCEPHALY AS A PROTECTIVE FACTOR OF NEUROPSYCHOMOTOR DEVELOPMENT IN FETAL SURGERY FOR OCCIPITAL ENCEPHALOCELE
Authors: Nicácio Jardel Mendonça , Cavalheiro Sergio , Costa Marcos Devanir Silva da , Dastoli Patricia Alessandra , Suriano Italo Capraro , Barbosa Mauricio Mendes , Sarmento Stéphanno Gomes Pereira , de Faria Tereza Cristina Carbonari , Moron Antonio Fernandes 
Published: January 2024

Abstract

Introduction: Encephaloceles are an NTCD characterized by herniation of intracranial contents through a defect in the bony framework of the skull. Its mortality rate can reach 33.3%. About one in three patients die from complications linked to the malformation. Of the patients who survive, approximately 50% have some degree of NPMD impairment or difficult-to-control seizures. The aim of this study was to analyze the relationship between good NPMD in patients undergoing fetal OE correction and the reversal of microcephaly in those same patients, comparing with the results found in patients who underwent postnatal surgery.
Methods: The records of patients diagnosed with OE who underwent surgery in the postnatal period and patients who underwent surgery in the fetal period between 19 and 27 weeks were retrospectively evaluated. All cases were diagnosed, evaluated, and monitored by the same healthcare service between July 2012 and July 2018. Twenty-two patients were selected for this study and separated into two groups, the Fetal Group (FG) and the Postnatal Group (PNG). The inclusion criteria in the FG were a singleton pregnancy, gestational age between 19 and 27 weeks, normal karyotype, maternal age greater than 18 years, progressive microcephaly documented by Obstetric Sonography, presence of OE with a volume greater than 10 mL, and contents of the hernial sac predominantly cystic (80% or more liquid content). The main exclusion criteria were fetal anomalies not associated with OE, chromosomal abnormalities, extruded brain parenchyma corresponding to more than 20% of the herniated content, presence of a brain stem in the encephalocele, venous sinus in the encephalocele, volume of the hernia sac less than 10 ml, and no progression to microcephaly other than atretic encephaloceles. All participants were subjected to a careful developmental assessment using the Bayley-II Scale up to two years and 11 months of age, and were monitored with CP measurements in the first year of life.. The relationship between the reversal of microcephaly and NPMD was also studied.
Results: In the FG, one case developed placental abruption, being removed from the study, which then totaled nine patients. In the PNG, two patients were excluded because they were diagnosed with Walker–Warburg syndrome and, in the other patient, the fetus had more than 20% of herniated brain parenchyma in the encephalocele, thereby totaling 10 cases. The head circumference adjusted for gestational age — obtained by nonlinear regression statistics with exponential plateau curve fitting, plotted with the median and the 5th to 95th percentiles based on the Snijders and Nicolaides fetal head circumference reference curves — showed a tendency towards reversal of progressive microcephaly after correction of encephaloceles in the FG. After analyzing NPMD using the BSID-II, for all nine patients in this group, the median was 98.7, with seven patients having a score greater than 90 points and two patients having a score below 50 points. One of the cases with a low score was a patient who was diagnosed with Knobloch Syndrome, and the MRI examination of the other case showed the presence of heterotopias and hypoplasia of the cerebellar vermis. In the PNG, NPMD assessment using the BSID-II ranged from 9 to 96.7, with a median of 27.8. We found a statistically significant difference in the median BSID-II between the Postnatal Group (27.8) and the Fetal Group (98.7), with p=0.007. Patients in the FG maintained normal CP development in the first year of life, while those in the PNG remained microcephalic, with p<0.001.
Conclusion: There is an evident superiority in NPMD demonstrated by the statistically significant difference in the Bayley II score in the FG patients when compared to the PNG patients. The reversal of microcephaly in the FG directly influenced good NPMD, and can be considered a protective factor for these patients. New studies need to be carried out in order to confirm the effectiveness of fetal surgery and provide greater understanding regarding its pathophysiology.