PEDBASE.org - The Pediatric Database - Detailed information of CRANIOSYNOSTOSIS

CRANIOSYNOSTOSIS

DEFINITION:

A congential anomaly of the CNS characterized by premature closing of one or more cranial sutures due to abnormalities of skull development.

EPIDEMIOLOGY:

incidence: ½,000 live births
age of onset:
- most cases evident at birth
risk factors:
- familial - autosomal dominant and autosomal recessive
  - chrom.#: 7p21.3-p21.2
  - gene: ?
- M = F (except in sagittal type where M > F (4:1))
- genetic syndromes account for 10-20% of cases:
  - Apert Syndrome
  - Chotzen Syndrome
  - Pfeiffer Syndrome
  - Carpenter Syndrome
  - Crouzon Syndrome

CLASSIFICATION:

1. Primary

etiology unknown but may involve abnormal cranial suture development which leads to inactive cranial suture growth re-sulting in the failure of adjacent cranial bones to increase in size perpendicular to the affected suture -> lack of growth of skull perpendicular to affected suture and overgrowth of skull parallel to the affected suture

2. Secondary

results from failure of brain growth and expansion

TYPES:

Suture % Skull Shape

Sagittal 40 scaphocephaly

Bicoronal 20 brachycephaly

Unicoronal 15 plagiocephaly (frontal)

Coronal + Sagittal 10 acrocephaly

Total 10 microcephaly

Metopic 4 trigonocephaly

Lambdoid + Sagittal 1 plagiocephaly (occipital)

CLINICAL FEATURES:

1. Craniosynostosis

abnormally-shaped head
prominent bony ridge over affected suture

2. Complications

hydrocephalus
increased intracranial pressure (ICP)
developmental delay

3. Sagittal Craniosynostosis

head shape: scaphocephaly
- long and narrow skull (increased A-P diameter)
- prominent occiput and broad forehead
- small or absent anterior fontanelle
usually not associated with other congenital malformations, a family history, or complications
normal neurologic examination

4. Bicoronal Craniosynostosis

head shape: brachycephaly
- wide and short skull (decreased A-P diameter)
characteristic deformity of orbits:
- shallow with poorly formed orbital ridges & frontal bone leads to a decreased orbital volume and results in:
  - proptosis -> corneal damage
  - orbital hypertelorism
  - nasolacrimal duct narrowing -> conjunctivitis
  - decreased visual acuity (optic nerve damage)
complications:
- hydrocephalus +/- increased ICP
associated anomalies:
- choanal atresia and high-arched palate
- hypoplasia of maxilla with prominent lower jaw and poor dental occulsion
associated syndromes:
- Acrocephalosyndactyly Syndromes

5. Unicoronal Craniosynostosis

head shape: plagiocephaly (frontal)
- marked craniofacial asymmetry
- unilateral flattening of the forehead
- elevation of ipsilateral orbit and eyebrow
- prominence of ipsilateral ear
- ipsilateral orbital ridge poorly formed -> proptosis and malalignment of eyes

6. Coronal + Saggital Craniosynostosis

head shape: acrocephaly
- cone-shaped head
- anterior fontanelle may remain widely opened
may be associated with increased ICP
associated syndromes:
- Pfeiffer Syndrome

7. Total Craniosynostosis

head shape: microcephaly
- skull has a normal shape but small
may be associated with increased ICP and developmental delay

8. Metopic Craniosynostosis

head shape: trigonocephaly
- keel-shaped forehead (prominent frontal ridge visible externally) -> triangular-shaped
- thickened frontal bones
deformity of orbits:
- hypotelorism
- flattened orbital ridges
may be associated with developmental abnormalities of the fore-brain

9. Lambdoid + Sagittal Craniosynostosis

head shape: plagiocephaly (occipital)
- flattened occipital bone
- bulging of frontal bone
- may be unilateral

INVESTIGATIONS:

1. Imaging Studies

1. Skull X-Ray/CT

fused sutures

MANAGEMENT:

1. Team Approach

multidisciplinary pre-op evaluation
- Paediatrics, Surgery, Neurology, Psychology, Genetics,
- Ophthalmology
- to investigate for other malformations or complications, i.e., hydrocephalus or increased ICP

2. Craniotomy

directed to correct the skull to prevent intracranial and oph-thalmologic complications
should be corrected within the 1st year of life
- elevation and contouring of bones easier
- reossification and remodelling occur rapidly
- facial involvement still minimal

3. Supportive

genetic counselling
- recurrence risk
- rule out syndrome
multidisciplinary Craniofacial Team
- follow for
  - disorders of speech and hearing
  - respiratory or feeding problems due to deviated nasal septum or choanal atresia
  - long term ophthalmologic problems

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