Module 5 - Head and Neck

Congenital and Acquired Craniofacial Reconstruction


A. Craniosynostosis vs. Craniofacial dysostosis

Virchow's Law - Premature fusion of a cranial suture inhibits normal skull growth perpendicular to the fused suture and allows compensatory growth at the open sutures.

Classification is based on skull shape

Craniosynostosis:

  • Scaphocephaly
  • Brachycephaly
  • Plagiocephaly
  • Trigonocephaly
  • Oxycephaly
  • Turricephaly

Craniofacial Dysostosis:

  • Carpenter
  • Crouzon
  • Apert's
  • Sathre-Chotzen
  • Pfeiffer
  • Kleeblattschadal

 

B. Functional Considerations

  • Intracranial volume triples within the first year of life and reaches four-times by 2 y/o
  • Hydrocephalus affects as many as 5-10% of craniosynostosis/ craniodysostosis patients

 

C. Etiopathogenesis and Incidence

  • Isolated is related to the functional effect of the suture where syndromic occurs with primary defects in morphogenesis
  • Primary or secondary allows for better characterization of the underlying cause
  • Hematologic disorders, malformations (microcephaly/encephalocoele), metabolic disorders (hyperT4, Vitamin D deficiency), iatrogenic disorders (hydrocephalus treated with VP shunt)
  • Simple 78% or Compound 16%
  • Isolated 94% or Syndromic 6%
  • Primary or Secondary
  • Significant predominance in Caucasians
  • Males > Females
  • 1:200 live births

 

D. Investigations

1. CT Scan/ X-ray

  • Spiral 3-D CT scan lens dose 8.9mSv vs. 24.6mSv for standard 3-D
  • 1mm cuts of cranium and 3mm cuts of facial bones

2. Radiologic Findings

Primary Findings

  • Bony bridging along suture line, heaped up bone on suture, sutural narrowing, indistinctiveness of the suture
  • Often unreliable in the first 3 months

Secondary Findings

  • Altered calvarial shape, fontanelle changes, facial anomalies, effacement of underlying subarachnoid space
  • Harlequin sign in plagiocephaly (elevation of the ipsilateral lesser spenoid wing)

3. Clinical Exam

  • Sutures palpable in scaphocephaly and trigocephaly but only 1/15 coronal synostoses is palpably ridged and 0% of lambdoid sutures are palpably ridged.

4. Pressure Measurements

  • Finger printing or Copper beaten (on X-ray)
  • Papilledema (late optic atrophy)

5. Mental Development

  • Unclear for unisutural non-syndromal synostosis
  • Significant risk in syndromal synostosis due to skull base involvement
  • Increasing risk with increasing number of sutures fused
  • Volume measurement alone does not correlate with raised ICP

 

E. Brain Growth & Mental Development

Marchac & Renier concluded (some disagreement with this)

  1. Intracranial hypertension can occur in all types of crainosynostosis and this increases with coronal suture and multiple suture involvement
  2. Mental development decreases with time in unoperated cases
  3. Surgery halts this progression

Oxycephaly

  • Oxus = pointed
  • Only involves the cranial vault (normal midface)
  • Only occurs in children > 2-3 yrs
  • Cause - late closure of the coronal sutures +/- sagittal suture
  • Supraorbital bar is recessed obliquely with an absence of fronto-nasal angle
  • Exophthalmic appearance due to short orbital roof
  • Upper forehead narrow and tilted backwards in continuity of nose

Scaphocephaly

  • Dolichocephaly vs. Sagittal suture synostosis
  • Correction by total skull re-shaping vs. strip craniectomy
  • Endoscopic sutural excision described by Jimenez & Barone 1998

Plagiocephaly (Anterior)

  • Usually refers to uni-coronal synostosis
  • The most complete presentation of craniofacial asymmetry
  • Females > Males
  • 9 - 15%
  • 10 times more common than unilateral lambdoidal synostosis
  • Bony structures more displaced in transverse and A-P direction than vertically
  • Deformational plagiocephaly occurs more frequently than either of the synostotic forms of plagiocephaly (between 5-48% of healthy newborns)
  • One must differentiate synostotic (malformational) from non-synostotic form (deformational) plagiocephaly (see below)

> Deformational Plagiocephaly (Non-synostotic)

  • Ipsilateral superior orbital rim - higher
  • Ipsilateral ear - anterior/higher
  • Ipsilateral palpebral fissure - even or lower
  • Nasal root - ipsilateral
  • Ipsilateral malar - anterior
  • Chin - contralateral
  • Ipsilateral:

    > Forehead - flat

    > Superior obital rim - up

    > Ear - anterosuperior

    > Malar eminence - anterior

    > Palpebral fissure - round

> Malformational Plagiocephaly (Synostotic)

  • Ipsilateral superior orbital rim - lower
  • Ipsilateral ear - posterior/lower
  • Ipsilateral palpebral fissure - mixed
  • Nasal root - contralateral
  • Ipsilateral malar - posterior
  • Chin - ipsilateral
  • Ipsilateral:

    > Forehead - flat

    > Superior orbital rim - down

    > Ear - posterioinferior

    > Malar eminence - posterior

    > Palpebral fissure - slit-like

The constellation of physical findings can be remembered by imagining that the craniofacial skeleton is twisted about a vertical axis (near the clivus). The upper 1/2 of the cranium rotated in one direction the lower 1/2 below the orbit in the opposite direction with increased facial height on the involved site.

 

F. Plagiocephaly

Plagios = oblique, aslant; Kephale = head

Calvarial shape

  • Oxycephaloc calvarial shape
  • Frontal bossing and elevated supraorbital rim (harlequin sign)
  • Shortened anterior cranial fossa, pteryon elevated
  • Advanced glenoid fossa and petrous temporal bone

Sutures

  • Unilateral coronal synostosis
  • Contralateral deviation of the bregma
  • Ipsilateral deviation of the lambda
  • Shortening of sphenozygomatic and sphenofrontal sutures

Orientation of the Face

  • Normal occlusion, oblique nose - root deviated to ipsilateral (synostotic) side & tip near midline
  • Ipsilateral - Forehead flat, auricle is advanced, eyebrow elevated, palpebral fissure shortened and rounded with lateral and medial canthal dystopia
  • Contralateral - Forehead bossed, pseudoptosis, lowered eyebrow

 

G. Brachycephaly

  • Incidence 9-15% of synostosis
  • Bilateral coronal sutural synostosis
  • Can be associated with increased ICP especially in syndromal cases such as Crouzon's and Apert's

 

H. Trigonocephaly

  • Marchac incidence 14% (237 of 1713 patients)
  • Others <8-10.3%
  • Males > Females (3.3:1)
  • 20% are syndromal
  • Isolated closure of the metopic suture
  • No significant risk of increased intracranial pressure
  • Can be associated with hypotelorism

 

I. Occipital Plagiocephaly

  • True posterior plagiocephaly is uncommon 3% (3-20%)
  • Must differentiate lambdoidal synostotic form from others
  • Positional, torticollis, asymmetric brain injury, spine anomalies, asymmetric tone, incidence of OP increased with side sleeping habitus (AAP-SIDS prevention)

J. Lambdoidal Synostosis

Radiologically (1996 Lo et al.)

  • CT scan - rotation of skull base - line from crista galli through mid anterior and posterior clinoids will not pass through the centre of foramen magnum

Indications

  • Increased ICP
  • Esthetic
  • Ocular

Risks and Complications

  • Blood transfusions, injection, relapse/recurrence, death, air embolism, scars, alopecia, ocular, brain injury


Author: Dr. R. Bendor-Samuel