Current controversies in prenatal diagnosis 4: Should fetal surgery be done in all cases of severe diaphragmatic hernia?

Several groups involved in fetal surgery now have the requisite skills for FETO but the widespread development of this intervention remains controversial. There are several fundamental areas of disagreement. Some of the American literature suggests that improvements in neonatal care have led to a fundamental shift in survival without fetal intervention. Despite the fact that some of these observations were made in 1997 (Wilson et al., 1997), they do not seem to have affected more recent outcomes (Hedrick et al., 2007; Datin-Dorriere et al., 2008). Prospective datasets representing both regions are needed to establish whether these differences are real or related to local study bias. To some extent, this first area of disagreement is irrelevant if a subgroup of cases with severe disease and extremely poor prognosis can be confidently identified. Once again, there is considerable disagreement over this. Although both liver herniation and LHR seem to be prognostic, there is disagreement on whether they are independent predictors and for that reason the European trial will take both variables into account. It is expected that other methods, assessing volume of the lung or herniated liver as well as vasculature, may further refine prediction of outcome. Although clinicians representing both sides of this debate call for a randomized controlled trial to resolve some of these issues, it is important to recognize that, due to the differences discussed earlier, they are not aiming to examine the same hypothesis. The European FETO study will not examine the issue of whether fetal intervention improves survival in the most severe group of cases. This may be left to American clinicians to examine. In the meantime, the European trial will answer important questions regarding the timing of the FETO procedure and will begin to address the issue of more widespread use of this technique with the aim of improving long-term morbidity as well as survival for affected infants. Both sides of the debate agree that in order to resolve these controversies, TO should currently not be performed outside of well-designed clinical trials.