GDA 6.txt

  1. craniosynostosis
    • (or craniostenosis):
    • Premature fusion of cranial sutures resulting in deformity of cranial vault
    • 1. Growth restriction perpendicular to fused suture
    • 2. Compensatory skull overgrowth in unrestricted areas
    • May also have Increased intracranial pressure (ICP), mental retardation, visual defects and cosmetic deformity are frequent causes of morbidity.
    • 1/2000 (3.1~4.8 in 10,000 live births)
  2. Simple CS
    involving only one suture
  3. Compound CS
    two or more sutures are involved
  4. Primary CS
    • (Idiopathic or Familial):
    • usually manifests as a component of various craniofacial syndromes without clearly known causes or may result from genetic mutations
  5. Secondary CS:
    results from a known underlying systemic or metabolic disorders such as hyperthyroidism, hypercalcemia, vitamin D deficiency, sickle cell disease and the conditions like microcephaly and encephalocele with diminished growth stretch at sutures
  6. Syndromic CS:
    • about 10~20% of CS with extra-cranial anomalies (facial, limb, ear and/or heart malformations) diagnosed early in life
    • more coronal CS
    • seen in female and sagittal CS in male

    • Non-syndromic CS
    • (Isolated): constitutes 80~90% of CS cases without extra- cranial deformities and affects sagittal, coronal, metopic and lambdoid sutures (in descending order of frequency)
  7. Three types of articulations:
    • 1. Sutures (Synarthrosis)– cranial vault
    • 2. Synchondroses-- cranial base
    • 3. Synovial joints-- TMJ with articular disk
  8. Cranial Cartilages
    • Primary cartilage: Meckel’s
    • Secondary cartilages: condylar,coronoid,symphyseal
    • zygmotic
  9. Neurocranium
    • (surrounds the brain)
    • Cranial Embryology
    • Skull vault->Dermatocranium—Membranous BF (CNC&PM)
    • Skull base->Chondrocranium-- Endochondral BF
  10. Viscerocranium
    • (forms the face)
    • Cranial neural crest (CNC)
    • Mandible
    • Maxilla
  11. Sutures
    • Major
    • a. Metopic (frontal in utero)
    • b. coronal
    • c. sagittal
    • d. lambdoi:
    • 1. squamosal
    • 2. synchondroses of the mid and posterior skull base
  12. Sagittal suture fusion:
    • Results in restriction of biparietal growth (rare with neurologic deficits and elevated ICP)
    • Dolichocephaly (Greek: dolikhos=long)
    • Scaphocephaly (Greek: scaphe=boat): a subset of Dolichocephaly with obvious ridging fused sagittal sutures, the most common isolated CS in male
  13. Coronal suture fusion
    • results in restriction of anterior-posterior calvarial growth
    • (cause secondary facial abnormalities: midface hypoplasia and Harlequin Eye)
    • Brachycephaly (Greek: brakhu=short): from bicoronal fusion
    • Plagiocephaly (Greek: plagios=oblique): from unicoronal fusion
  14. Metopic suture fusion:
    • usually occurs before 6 months (3-9 M) of age in utero fusion and 1/3 cases are syndromic with other midline anomalies (brain and palate)
    • Trigonocephaly (Greek: trigonos= three angles): milder form “metopic ridge”
  15. Lambdoid suture fusion:
    • Turrecephaly (Greek: turri=tower): bilateral lambdoid suture fusion (flattened occiput)
    • Posterior plagiocephaly: unilateral lambdoid suture fusion
  16. Sagittal and Coronal sutures fusion:
    • severe combinational synostoses may result in microcephaly (raised ICP and neurologic impairment)
    • Oxycephaly (Greek: oxys=sharp)
  17. Sagittal, Coronal and Lambdoid sutures fusion
    • generally have severe neurological impairment
    • Kleeblattschadel (German: kleeblatt=cloverleaf; schadel=skull)
  18. Deformational or positional plagiocephaly
    • Differential diagnosis:
    • not a true synostosis due to no sutures are fused.
    • It caused by compressional forces in utero and modulated by postnatal preferential head positioning in infants sleeping on their back.
  19. CS SYNDROMES (ACP constitutes 2/3)
    • Craniofacial features (CF): skull deformity with raised ICP, hydrocephalus,optic atrophy and respiratory,speech and hearing problems, need surgucal intervention
    • Noncraniofacial features (NCF): digital anomalies (H&F), cervical fusion, short humerus and femur and syndactyly.
  20. Apert’s syndrome:
    • (1906 by Apert)
    • CF: bilateral coronal synostosis at birth, small and malformed skull base, large
    • fontanels and a gaping frontal midline defect; brain malformation and mental retardation
    • NCF: cervical vertebral fusion(C5-6) (joint ankylosis), digital anomalies (H&F), acrocephalosyndactyly
  21. Crouzon’s syndrome:
    • (1912 by Crouzon)
    • CF: coronal suture and minor skull base suture closure (brachycephaly), midfacial
    • hypopalsia, parrot-beak nose, hypertelorism and hydrocephalus. NCF: short humerus and femur, partial syndactyly (type II Crouzon), carpal fusion
  22. Pfeiffer’s syndrome:
    • (1964 by Pfeiffer) (three types)
    • Type I: most common, hearing loss with auditory stenosis and hypertelorism
    • Type II: cloverleaf skull and severe proptosis
    • Type III: features of Type I and II with mental retardation and hydrocephalus
  23. Gli3
    • Greig syndrome
    • first CS gene
  24. MSX-1&2
    • Boston type CS
    • second CS gene
  25. FGFR2
    • Crouzon syndrome started journey of exploration of genes involved in syndromic CS (FGFR1,3, Twist— all in
    • autosomal dominant inheritance pattern)
  26. Runx2
    master in control of osteochondrogenesis
  27. Nell 1
    a CS associated gene identified by Differential Display PCR
  28. strip craniectomy
    • Surgical manegement:
    • (usually most effective in the 1st year of life using “strip craniectomy” technique)
    • a typical way for primary CS with obvious restriction of brain
    • growth and raised ICP. ( or Endoscopic-assisted minimally invasive suturectomy plus cranial helmet). Multiple surgical corrections may be needed for syndromic patients than nonsyndromic ones due to facial suture anomaly.)
Card Set
GDA 6.txt