Congenital anomalies in the teratological collection of Museum Vrolik in Amsterdam, The Netherlands. IV: closure defects of the neural tube.

The Museum Vrolik collection of the Department of Anatomy and Embryology of the University of Amsterdam, founded by Gerardus Vrolik (1775-1859) and his son Willem Vrolik (1801-1863), consists of more than 5,000 specimens of human and animal anatomy, embryology, pathology, and congenital anomalies. Recently, the collection of congenital anomalies, comprising 360 specimens, was recatalogued and redescribed according to contemporary morphogenetic opinions. The original descriptions, as far as preserved, were compared with the clinical and additional findings. Based on the classification by closure site, proposed by Van Allen et al. [1993], the following closure defects of the neural tube were diagnosed in 107 specimens: craniorachischisis, holoacranium with partial rachischisis, faciocranioschisis, holoacranium, meroacranium, occipital cranioschisis, frontal encephalocele, parietal encephalocele, occipital encephalocele, occipital encephalocele with rachischisis, occipito-cervical encephalocele, thoracolumbar spina bifida, lumbosacral spina bifida, occult sacral dysraphism, and sacrococcygeal dysgenesis. Furthermore, we diagnosed three conditions that did not appear in the aforementioned classification; we named these conditions craniorachischisis totalis, occipital craniorachischisis, and thoracolumbosacral spina bifida. The results of our study are in line with the assumption that particularly occipito-cervical neural tube defects are associated with concomitant anomalies and are more common in females. The results support the idea of multisite closure of the human neural tube.