Congenital malformations of the nervous system (Q00-Q07)

Neural tube defects affect the brain and spinal cord, and are among the most common of the congenital anomalies.
In anencephaly, the absence of the brain and calvaria can be total or partial. Craniorachischisis is characterized by anencephaly accompanied by a contiguous bony defect of the spine and exposure of neural tissue.
In open spina bifida, a bony defect of the posterior vertebral arches (in this case, the lower thoracic vertebrae) is accompanied by herniation of neural tissue and meninges and is not covered by skin.
In iniencephaly, dysraphia in the occipital region is accompanied by severe retroflexion of the neck and trunk.
In encephalocele, the brain and meninges herniate through a defect in the calvaria.
In closed spina bifida, unlike open spina bifida, the bony defect of the posterior vertebral arches (in this case, the lumbar vertebrae), the herniated meninges, and neural tissue are covered by skin.
The most prevalent types of neural tube defects are anencephaly, encephalocele and spina bifida.






Anencephaly (Q00.0)

A total or partial absence of the brain, together with total or partial absence of the cranial vault and the covering skin



Craniorachischisis(Q00.1)

The presence of anencephaly with a contiguous spine defect without meninges covering the neural tissue (rachischisis).





Iniencephaly (Q00.2)

A rare and complex neural tube defect characterized by extreme retroflexion of the head, variably combined with rachischisis of the cervical and thoracic spine and, more rarely, with occipital encephalocele. In iniencephaly, the cranium is always closed.



Frontal encephalocele (Q01.0)

Herniation of brain tissue, usually covered by meninges, through a defect in the frontal bone.



Nasofrontal encephalocele (Q01.1)

Herniation of brain tissue, usually covered by meninges, through an opening between the frontal bone and the nasal and ethmoid bones.


Occipital encephalocele (Q01.2)

Herniation of brain tissue, usually covered by meninges, through an opening in the occipital bone.


Parietal encephalocele (Q01.80)

Herniation of brain tissue, usually covered by meninges, through an opening in one of the parietal bones.


Orbital encephalocele (Q01.81)

Herniation of brain tissue, usually covered by meninges, through one of the orbits.


Nasal encephalocele (Q01.82)

Herniation of brain tissue, usually covered by meninges, through an opening in the nasal region.


Cervical spina bifida

Most cases of cervical spina bifida will eventually develop hydrocephalus, although this may not be immediately obvious at birth; therefore, coding for cervical spina bifida with or without hydrocephalus could be difficult at birth. Close follow-up of these neonates is important for consideration of shunt surgery.


Cervical spina bifida with hydrocephalus (Q05.0)

Protrusion of meninges and/or spinal cord through an opening in the cervical region of the spine, associated with hydrocephalus. It may be open, with or without membrane covering; or closed, covered by normal- appearing skin. Hydrocephalus is present as a result of obstruction to the flow of cerebrospinal fluid, secondary to the hindbrain herniation associated with Chiari II malformation.


Cervical spina bifida without hydrocephalus (Q05.5)

Protrusion of meninges and/or spinal cord through an opening in the cervical region of the vertebral column. It may be open, with or without membrane covering; or closed, covered by normal-appearing skin.





Thoracic spina bifida

Most cases of thoracic spina bifida will eventually develop hydrocephalus, although this may not be immediately obvious at birth; therefore, coding for thoracic spina bifida with or without hydrocephalus could be difficult at birth. Close follow-up of these neonates is important for consideration of shunt surgery.


Thoracic spina bifida with hydrocephalus (Q05.1)

Protrusion of meninges and/or spinal cord through an opening in the thoracic region of the vertebral column, associated with hydrocephalus. It may be open, with or without membrane covering; or closed, covered by normal-appearing skin. Hydrocephalus is present as a result of obstruction to the flow of cerebrospinal fluid, secondary to the hindbrain herniation associated with Chiari II malformation.

Thoracic spina bifida without hydrocephalus (Q05.6)

Protrusion of meninges and/or spinal cord through an opening in the thoracic region of the vertebral column, associated with hydrocephalus. It may be open, with or without membrane covering; or closed, covered by normal-appearing skin. Hydrocephalus is present as a result of obstruction to the flow of cerebrospinal fluid, secondary to the hindbrain herniation associated with Chiari II malformation.

Lumbar spina bífida

Some cases of lumbar spina bifida will eventually develop hydrocephalus, and this may not be immediately obvious at birth; therefore, coding for lumbar spina bifida with or without hydrocephalus could be difficult at birth. Close follow-up of these neonates is important for consideration of shunt surgery.


Lumbar spina bifida with hydrocephalus (Q05.2)

Protrusion of meninges and/or spinal cord through an opening in the thoracic region of the vertebral column, associated with hydrocephalus. It may be open, with or without membrane covering; or closed, covered by normal-appearing skin. Hydrocephalus is present as a result of obstruction to the flow of cerebrospinal fluid, secondary to the hindbrain herniation associated with Chiari II malformation.

Lumbar spina bifida without hydrocephalus (Q05.7)

Protrusion of meninges and/or spinal cord through an opening in the thoracic region of the vertebral column, associated with hydrocephalus. It may be open, with or without membrane covering; or closed, covered by normal-appearing skin. Hydrocephalus is present as a result of obstruction to the flow of cerebrospinal fluid, secondary to the hindbrain herniation associated with Chiari II malformation.

Sacral spina bifida

Few cases of sacral spina bifida will develop hydrocephalus, compared with the other types of spina bifida. The presence of hydrocephalus in infants with sacral spina bifida may not be immediately obvious at birth; therefore, coding for sacral spina bifida with or without hydrocephalus could be difficult at birth. Close follow-up of these neonates is important for consideration of shunt surgery.


Sacral spina bifida with hydrocephalus (Q05.3)

Protrusion of meninges and/or spinal cord through an opening in the sacral region of the vertebral column, associated with hydrocephalus. It may be open, with or without membrane covering; or closed, covered by normal- appearingskin. Hydrocephalus is present as a result of obstruction to the flow of cerebrospinal fluid, secondary to the hindbrain herniation associated with Chiari II malformation.

Sacral spina bifida without hydrocephalus (Q05.8)

Protrusion of meninges and/or spinal cord through an opening in the sacral region of the vertebral column, associated with hydrocephalus. It may be open, with or without membrane covering; or closed, covered by normal- appearingskin. Hydrocephalus is present as a result of obstruction to the flow of cerebrospinal fluid, secondary to the hindbrain herniation associated with Chiari II malformation.




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