spinal dysraphism
Spinal dysraphisms refer to a broad group of malformations affecting the spine and/or surrounding structures in the dorsum of the embryo. They are a form of neural tube defect.
Pathology
The neural tube is formed by the lengthwise closure of the neural plate, in the dorsum of the embryo.
The upper part of the neural tube forms the forebrain, midbrain and hindbrain. The lower part of the neural tube forms the spinal canal. Dysraphism results when the neural plate does not fuse completely in its lower section.
Classification
Spinal dysraphism can be broadly divided into two different clinicoradiological entities :
- open spinal dysraphism (formerly spina bifida aperta or cystica): occurs when the cord and its covering communicate with the outside; no skin or tissues cover the sac
- myelomeningocele (98% of open spinal dysraphism)
- myelocele
- hemimyelomeningocele
- hemimyelocele
- closed spinal dysraphism (formerly spina bifida occulta): occurs when the cord is covered by other normal mesenchymal elements
- with subcutaneous mass
- lipoma with dural defect
- terminal myelocystocele
- meningocele
- limited dorsal myeloschisis
- without subcutaneous mass
- posterior spina bifida (isolated defect of the posterior neural arch of vertebra)
- intradural lipoma
- filar lipoma
- tight filum terminale
- persistent terminal ventricle
- disorders of midline notochordal integration
- dorsal dermal sinus
- dorsal enteric fistula
- neurenteric cyst
- split cord malformations
- disorders of notochordal formation
- caudal regression syndrome
- Type 1
- Type 2
- segmental spinal dysgenesis
- caudal regression syndrome
- with subcutaneous mass
Associations
Associated abnormalities of mesenchymal development occur often. Hence, lipomas and/or teratomas may be associated with any type.
History and etymology
Dysraphism is formed from the greek root raphe which means ridge or seam.
See also
Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu Dysrhaphie:
