Nonsyndromic craniosynostosis Flashcards
What is craniosynostosis?
The premature fusion of one or more skull sutures
What is Virchow’s law of skull sutures?
That the skull grows perpendicular to the open suture. When a suture fuses the skull is forced into a compensatory growth pattern.
What is the theory of the pathogenesis of craniosynostosis?
Pathological interaction between the dural and abnormal osteoblasts are the suture front. The osteoblasts proliferate more rapidly and have an increased response to growth factors.
What are the causes of secondary craniosynostosis (i.e. not in utero)?
Rickets Hypophosphataemia Hyperthyroidism Sickle cell Polycythaemia vera MPS Over shunting Medications (incl chlorpheniramine, nitrofurantoin, methotrexate and valproate)
What are the indications for surgery in non-syndromic synostosis?
High ICP
Cosmesis
What is the historical summary for the treatment of synostosis?
Lannelongue 1890 - Suture release
Mehner 1921 - Suturectomy
Tessier 1950 - Cranial vault remodelling
Epstein 1980s - Advanced remodelling (FOR / TCR / PVE / Pi procedure)
Jimenez and Barone 1990 - Endoscopic
What is the incidence of non-syndromic synostosis?
Sagittal - 1/5,000 (males)
Coronal - 1/10,000 (females)
Metopic - 1/10,000 (males)
Lambdoid - 1/20,000 (females)
Which suture is most commonly affected in syndromic synostosis?
Coronal synostosis - more likely to be bilateral
What other diseases are related to metopic synostosis?
Midline abnormalities including heart defects
When is lambdoid synostosis seen in non-syndromic cases?
Rare but can be seen with sagittal synostosis
Whar head shape is seen with sagittal synostosis?
Scaphocephaly - long and narrow head. Associated with frontal and occipital bossing
What head shape is seen with coronal synostosis?
Anterior plagiocephaly in unilateral cases with flat forehead, harlequin eye (lateral orbit pulled up) and ear pulled forward unilaterally.
Bilateral coronal synostosis leads to brachycephaly which is very wide and flat.
What head shape is seen with metopic synostosis?
Trigonocephaly resulting in a triangular-shaped forehead. Eyes are close (hypotelorism). Posterior parietal regions are full in compensation for the narrow forehead.
What head shape is seen with lambdoid synostosis?
Posterior plagiocephaly - trapezium shape with ipsilateral ear pulled back with forehead flattening. There are compensatory enlargements of contralateral lambdoid/parietal regions.
What mutation is found in coronal synostosis?
FGFR-3 mutation in bicoronal cases and most are female
What proportion of patients with single suture synostosis develop raised ICP?
ICP >15 mmHg in 10% (compared to 40% in syndromic cases)
How does raised ICP manifest in very young children with synostosis?
Regression of mild stones Sleeping difficulties Behavioural changes Headache Nausea / Vomiting
What is doliocephaly?
An abnormal head shape similar to scaphocephaly due to in-utero positioning. This will correct over time.
When does the metopic suture close normally?
Between 3-9 months. There may be a ridge as it closes. The anterior fontanelle remains open until the suture closes.
What proportion of patients developed raised ICP in unoperated unicoronal synostosis?
15%
At what age does fundoscopy become a reliable indicator of raised ICP?
8 years old
What facotrs are reliable indicators of raised pressure in children <18 months?
Copper beating
Sellar erosion
Suture diastasis
Volcano sign
What is the correlation between language dysfunction and metopic synostosis?
Language dysfunction is greatest in patients with worse deformity, but this does not improve after surgical correction.
What objective measure if used to assess children’s development?
Bayley’s developmental assessment
What skull morphology is associated with trigonocephaly?
Triangular shaped forehead
Temporal narrowing
Hypotelorism (narrow BFZ)
Biparietal widening
Supra-orbital resession
Anteriorly displaced coronal sutures
What skull morphology is associated with unicoronal synostosis?
TRAPEZIUM deformity:
Ipsilateral frontal flattening (smaller volume anteroir cranial fossa)
Ipsilateral temporal bulding
Contralateral frontal bulding
Deviation of nasal root to ipsilateral side
Anterior displacement of ipsilateral ear
Harlequin eye deformity
Narrow sphenopetrosal angle
Narrow medio-lateral dimension of the orbit
