Craniorachischisis

Craniorachischisis is a variant of rachischisis that occurs when the entire spinal cord and brain are exposed – simultaneous complete rachischisis and anencephaly.^([Wikipedia])

Craniorachischisis and anencephaly represent the most extensive of the neural tube defects. In craniorachischisis the neural tube from the midbrain down to the upper sacral region of the spinal cord remains open (Fig. 26.1), there being no fusion of the tube.

The neural tube closure occurs around day 28 after conception; its closure failure may result in a defect that can range from anencephaly, incompatible with life, to small meningoceles.[1] The definition of neural tube defects (NTD) include anencephaly, craniorachischisis, iniencephaly, meningocele, meningomyelocele, and encephalocele, but not isolated findings of hydrocephalus or spina bifida oc[c]ulta.[1] Iniencephaly, from the ancient Greek "inion" meaning "nape of the neck", had its first report by Saint-Hilaire in 1836,[2] is characterized by a variable defect of the occipital bone, resulting in a large foramen magnum; partial or total absence of the cervical and thoracic vertebrae with irregular melting of those present, accompanied by incomplete closure of arcs and/or vertebral bodies, marked lordosis, hyperextension of the cervicothoracic spine; and a face deflected up.[3] The incidence is about 1:1000–1:2000 births,[4] then is a pretty rare NTD.

Craniorachischisis is readily diagnosed using ultrasound. However, it can be confused with other defects involving the brain – anencephaly, acrania or amniotic band syndrome.