THE PRENATAL MANAGEMENT OF NEURAL TUBE DEFECTS: TIME FOR A RE-APPRAISAL

Abstract

The prevalence of neural tube defects (NTD) in Europe is around 9 per 10,000 births making it one of the most frequent congential anomalies affecting the central nervous system. NTD encompass all anomalies that are secondary to failure of closure of the neural tube. In this review, we will first summarize the embryology and some epidemiologic aspects related to NTDs. The review focuses on myelomeningocele (MMC), which is the most common distal closure defect. We will describe the secondary pathologic changes in the central and peripheral nervous system that appear later on in pregnancy and contribute to the condition's morbidity. The postnatal impact of MMC mainly depends on the upper level of the lesion. In Europe, the vast majority of parents with a fetus with prenatally diagnosed NTDs, including MMC, opt for termination of pregnancy, as they are apparently perceived as very debilitating conditions. Animal experiments have shown that prenatal surgery can reverse this sequence. This paved the way for clinical fetal surgery resulting in an apparent improvement in outcome. The results of a recent randomized trial confirmed better outcomes after fetal repair compared to postnatal repair; with follow up for 30 months. This should prompt fetal medicine specialists to reconsider their position towards this condition as well as its prenatal repair. The fetal surgery centre in Leuven did not have a clinical programme for fetal NTD repair until the publication of the MOMS trial. In order to offer this procedure safely and effectively, we allied to a high volume centre willing to share its expertise and assist us in the first procedures. Given the maternal side effects of current open fetal surgical techniques, we have intensified our research programmes to explore minimally invasive alternatives. Below we will describe how we are implementing this.