Craniorachischisis

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Craniorachischisis is characterized by the combination of anencephaly (absence of the brain and cranial vault, without skin covering) with a contiguous bony defect of the cervical spine (also without meninges covering the neural tissue – rachischisis).

Fig. 3. Craniorachischisis

Fig. 3. Craniorachischisis

 

Photograph source: CDC–Beijing Medical University collaborative project.

Key findings in craniorachischisis (see Fig. 3):
  1. Head – anencephaly (absence of the brain and cranial vault).
  2. Covering – no skin covering residual brain tissue, spinal cord tissue, or cranial vault (calvarium).
  3. Spine – open (rachischisis) might be limited to the cervical spine, but the open defect can extend to the thoracic spine or even lumbar or sacral spine (craniorachischisis totalis).

Diagnosis

Prenatal. Craniorachischisis is readily diagnosed using ultrasound but can be confused with other defects involving the brain – anencephaly, acrania and amniotic band syndrome. Use programme rules (SOPs) to decide whether to accept or not accept prenatal diagnoses without postnatal confirmation (e.g. in cases of termination of pregnancy or unexamined fetal death).

Postnatal. Careful examination of the fetus or newborn can confirm the diagnosis of craniorachischisis and distinguish it from the other rare anomalies that involve the brain, cranium and spine.

Clinical and epidemiologic notes

Craniorachischisis is a lethal condition and is often an isolated, non-syndromic anomaly.
  • Eyes are normally formed; bulging is a result of absence of the frontal portion of the cranial vault.
  • Neck may appear to be shortened and is sometimes retroflexed.
  • Cerebellum and brain stem are intact.
  • Craniorachischisis is always an open lesion, with the anencephaly always being contiguous with the spinal lesion.
Additional clinical tips:
  • Craniorachischisis might co-occur with other anomalies: Cleft lip and palate, omphalocele, limb defects, or cyclopia.
  • Check for chromosomal anomaly: Case reports of trisomy 18 with craniorachischisis and omphalocele have been reported.
  • Craniorachischisis might be confused with:
    • Amniotic band or limb-body wall spectrum, which have other findings (facial schisis, limb and ventral wall anomalies, bands) and allow the differentiation from typical craniorachischisis.
    • Iniencephaly if spinal retroflexion is present.

Checklist for high-quality reporting

Craniorachischisis – Documentation Checklist
Describe in detail:
  • Defect – overall presentation.
  • Extent of spinal involvement (cervical spine or lower) – especially comment on and document the fact that the head involvement (anencephaly) and the spine defect are contiguous, without intervening normal-appearing spine.
  • Retroflexion of neck and spine – this is more typical of iniencephaly, so important to note.
  • If amniotic bands are present – disruptions by amniotic bands could possibly mimic severe atypical NTDs.

Take and report photographs: Show clearly the missing cranium; can be crucial for review.

Describe evaluations to find or rule out related and associated anomalies: 

  • Orbits – usually protruding but normally developed (do not include as an associated anomaly).
  • Head circumference will be small – do not code as microcephaly.
  • Spina bifida (mention but do not code contiguous defects).
  • Other anomalies or chromosomal abnormality.

Report whether autopsy (pathology) findings are available and if so, report the results.
Page last reviewed: March 11, 2021
Content source: Division of Birth Defects and Developmental Disabilities, NCBDDD, Centers for Disease Control and Prevention