Dura mater-preserving technique for fetal brain extraction after intrauterine death with prolonged retention.

Abstract

Examination of the fetal brain represents a crucial step in the diagnostic assessment of fetal death in utero, particularly in cases of unexplained intrauterine fetal death (IUFD). Prolonged intrauterine retention, advanced autolysis, and the intrinsic structural immaturity of the fetal brain frequently compromise tissue integrity, limiting diagnostic evaluability. We describe a brain extraction technique preserving the dura mater combined with a modified alcohol-formalin-acetic acid fixation protocol aimed at improving morphological preservation and diagnostic yield. Between 2017 and 2019, 295 fetal autopsies were performed at the regional reference center for SIUD-IRCCS Istituto Giannina Gaslini, Genoa, Italy. The method enables en bloc removal of the brain completely enveloped by the intact dura mater, which acts as a protective scaffold during handling and fixation. The brain is suspended in a modified Culling solution (40% buffered formalin at 10%, 40% ethanol at 95%, 20% glacial acetic acid) for approximately 20 days prior to serial sectioning according to the Charcot's technique. This approach appears to reduce mechanical disruption even in severely macerated cases, ensures uniform tissue compaction, shortens fixation times compared with formalin alone, and preserves cortical, ventricular, and brainstem anatomical relationships. It also allows gross exclusion of major abnormalities, including extensive intraventricular and intraparenchymal hemorrhages, and enables systematic inspection and sampling of the dural venous sinuses. Histological and immunohistochemical analyses demonstrated satisfactory preservation quality comparable to conventional methods. This simple and reproducible technique enhances evaluability in fetal autopsies and supports more reliable etiological assessment in cases of IUFD.