Spinal retroflexion in craniorhachischisis: its classification and limitations

Abstract

Spinal retroflexion has been studied in five stillborn human fetuses having craniorhachischisis. The findings show that retroflexion in this variant of anencephaly can be classified into severe, moderate and mild forms. The three grades can be differentiated from one another by the direction of the face, shape of the mentothoracic junction, extension of hairline on back, radiographic abnormalities of the spine, and the diaphragmatic defects. It is discussed that, though the anencephalies with severe or moderate degree of cervical retroflexion resemble iniencephaly in their features of spinal retroflexion, those having mild retroflexion are contrasted and should not be categorised with iniencephaly. It is suggested that for precision the term ‘spinal retroflexion’ should be used after duly prefixing it by an appropriate word (severe, moderate or mild) indicating the degree of retroflexion observed.

Prenatal diagnosis and pathoanatomy of iniencephaly

“…of spina bifida, omphalocele, diaphragmatic hernia, agenesis of the diaphragm, pulmonary hypoplasia or hyperplasia, abnormalities of the heart, renal maldevelopment, club-foot, gastro-intestinal atresia, etc. (Lewis 1897, Osborne 1948, Stark 1951, Cimmino & Painter 1962, Bose et al 1964, Cunningham 1965, Lemire et al 1972, Chaurasia & Wagh 1974, Chaurasia et al 1976, easily discernible (Chaurasia et al 1976). Iniencephaly should be differentiated When the malformation is restricted to the from anencephaly with simultaneous spinal cervical spine it is known as Klippel-Feil retroflexion (Lewis 1897, Chaurasia et al syndrome which most likely represents a 1976.…”

Neural tube closure and neural tube defects: Studies in animal models reveal known knowns and known unknowns

“…It is possible that it will be useful to take these extrapolations even further. Human CRS is often, but not always associated with spinal retroflexion [Chaurasia et al, 1976; Moore et al, 1997]. Frog embryos lacking PCP signaling also display both of these phenotypes [Wallingford and Harland, 2001].…”

“…On the other hand, mice lacking the RaldH2 gene display a fully open neural tube and a shortened axis, but there is no evidence of spinal retroflexion [Niederreither et al, 1999]. Since it has been suggested that the presence or absence of associated spinal retrofelxion with CRS may be informative for classification of human NTDs [Chaurasia et al, 1976], a similar association in model animals may also be informative.…”

Iniencephaly: prenatal diagnosis and management

“…Although the detection of a ®xed retroexion of the fetal head is highly suggestive of iniencephaly, the differential diagnosis should include other entities presenting with similar features such as certain forms of anencephaly (Lemire et al, 1972;Chaurasia et al, 1976;Salamanca et al, 1992) and Klippel±Feil syndrome (Gilmour, 1941;Gardner, 1979). Anencephaly with ®xed retro¯exion has easily discernible cervical vertebrae whereas iniencephaly does not (Lemire et al, 1972;Chaurasia et al, 1976;Salamanca et al, 1992). In the case of Klippel±Feil syndrome, it has been suggested that this is a mild form of iniencephaly, and that a continuum may exist linking these two entities (Gilmour, 1941;Gardner, 1979).…”