GDA 6.txt

• (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.
• EPIDERMIOLOGY
• 1/2000 (3.1~4.8 in 10,000 live births)

involving only one suture

two or more sutures are involved

• (Idiopathic or Familial):
• usually manifests as a component of various craniofacial syndromes without clearly known causes or may result from genetic mutations

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

• 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)

• 1. Sutures (Synarthrosis)– cranial vault
• 2. Synchondroses-- cranial base
• 3. Synovial joints-- TMJ with articular disk

• Primary cartilage: Meckel’s
• Secondary cartilages: condylar,coronoid,symphyseal
• zygmotic

• (surrounds the brain)
• Cranial Embryology
• Skull vault->Dermatocranium—Membranous BF (CNC&PM)
• Skull base->Chondrocranium-- Endochondral BF

• (forms the face)
• Cranial neural crest (CNC)
• Mandible
• Maxilla

• Major
• a. Metopic (frontal in utero)
• b. coronal
• c. sagittal
• d. lambdoi:
• 1. squamosal
• 2. synchondroses of the mid and posterior skull base

• 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

• 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

• 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”

• Turrecephaly (Greek: turri=tower): bilateral lambdoid suture fusion (flattened occiput)
• Posterior plagiocephaly: unilateral lambdoid suture fusion

• severe combinational synostoses may result in microcephaly (raised ICP and neurologic impairment)
• Oxycephaly (Greek: oxys=sharp)

• generally have severe neurological impairment
• Kleeblattschadel (German: kleeblatt=cloverleaf; schadel=skull)

• 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.

• 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.

• (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

• (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

• (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

• Greig syndrome
• first CS gene

• Boston type CS
• second CS gene

• Crouzon syndrome started journey of exploration of genes involved in syndromic CS (FGFR1,3, Twist— all in
• autosomal dominant inheritance pattern)

master in control of osteochondrogenesis

a CS associated gene identified by Differential Display PCR

• 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.)