CHAPTER 05: CRANIOFACIAL Flashcards
1
Q
How are congenital craniofacial abnormalities classified?
A
Classification (American Soc of Cleft lip and Palate)
- Clefts – Lip / Palate / Facial, Encephalocoeles
- Synostosis (syndromal or non-syndromal)
- Hypoplastic conditions (HFM, hemifacial atrophy)
- Hyperplastic and neoplastic conditions (fibrous dysplasia)
2
Q
What is the aetiology of craniofacial clefts?
A
1 in 25000 live births
Possible aetiology
- Failure of fusion of prominences
- Lack of mesodermal penetration
- Intra-uterine compression by amniotic bands
- Clefts can involve any or all layers of the face
- Soft tissue defect may not correspond to the bony abnormality
- May have hairline markers (hair growing along the line of the cleft)
3
Q
Who classified craniofacial clefts?
A
TESSIER CLASSIFICATION
- Facial clefts down from orbit
- Cranial clefts up from orbit
- Midline = 0
- Clefts can connect -> add up to 14
- Described as orbital and nasal clock-faces that overlap
- Orbitocentric/ Nasocentric/ Mixed/ Extended
4
Q
Is there another classification?
A
Van Der Meulen Classification
Cerebral Craniofacial Dysplasia
- Interophthalmic dysplasia
- Ophthalmic dysplasia
Craniofacial Dysplasia - Clefts and Synostosis
- Dysostoses (described according to anatomical location e.g. frontal, nasal, maxillary, zygomatic, temporal, maxillary, mandibular, and combinations of)
Craniofacial Dysplasia of other origin
- e.g. neurofibromatosis, vascular anomalies, fibrous dysplasia
5
Q
Who wrote the seminal paper on facial clefts?
A
Tessier Classification (J Max Surg 1976)
- excluding CL/P + CP, incidence of facial clefts = 5:100 000
- lateral clefts - tend to have more severe bony abnormalities
- medial clefts - tend to have more severe soft tissue abnormalities
6
Q
What are the principles of cleft craniofacial surgery?
A
- MDT
- Tailored to each patient
- Protect Vital Functions – Airway, Feeding, Eye
- Separation of Facial Cavities
Anatomic Subunit Repair – David Fisher Toronto – PRS June 2005
- Facial Skeleton: Remove abnormal elements, transpose skeletal components, bone graft defects
- Facial muscles: reattach to the skeleton in correct anatomical position
- Soft Tissues: reconstruct with local, regional or distant flaps.
7
Q
What are encephalocoeles?
A
Caused by herniation of the brain or its lining through a defect in the skull
Skeletal defect can be due to a craniofacial cleft
Classified by their composition
o Meningoceles = contain meninges
o Meningoencephaloceles = contain meninges and brain
o Cystoceles = meninges, brain and a portion of ventricle
o Myeloceles = portion of spinal cord
8
Q
What is Treacher-Collins Syndrome?
A
Mandibulofacial dysostosis, Franceschetti syndrome
- Chromosome 5q31-33 - AD
- 1 in 40000 - 70000 live births
- Characterised by Tessier 6, 7 and 8 cleft centred around zygoma
- Bilateral abnormalities of 1st & 2nd branchial arches – Failure of first arch neural crest and failure of fusion of mandibular and maxillary prominences.
Abnormalities
- Orbits - lower lid coloboma cleft 6, Hypertelorism, Anti-mongoloid slant, lacrimal apparatus may be absent
- Nose - narrow, deviated hooked, broad bridge
- Cheek - Absent or hypoplastic zygoma cleft 7
- Palate - cleft / high arch
- Mandible - Maxillary and mandibular hypoplasia, hypoplastic ramus TMJ
- Mouth - macrostomia
- Ear - abnormalies of external, middle and inner ear, microtia, cryptotia, hearing defects, BAHA
9
Q
What is the treatment for Treacher-Collins Syndrome?
A
Airway → difficulty due to mandibular and maxillary hypoplasia → nursing prone, trache.
Zygoma and Orbits → Calvarial bone graft to augment orbital floor and zygoma, > 7yrs old
Mandible → rib grafts, mandibular advancement, bimaxillary procedures, distraction.
Ear→ reconstruction, bone conduction hearing aids.
10
Q
What is craniosynostosis?
What is Virchow’s law?
What is the incidence of craniosynostosis?
A
Premature fusion of one or more sutures in the cranial vault or skull base → growth retarded in plane perpendicular to suture
Virchow’s law = compensatory skull growth parallel to a fused suture in craniosynostosis
Incidence
1 in 2500 live births
Non-syndromic = isolated (90%)
- 0.6 in 1000
- may be due to gestational / toxic influences
- sporadic congenital findings
- usu single suture
Syndromic (10-20%, 50% hereditary)
Genetic mutations in
- 70% of Crouzon, Pfeiffer or Saethre-Chotzen
- 100% of Apert
FGFR genes encode tyrosine kinase receptors
- FGFR 1: assoc w Pfeiffer
- FGFR 2: assoc w Pfeiffer, Apert, Crouzon
11
Q
What is the history of craniosynostosis?
A
400 BC Hippocrates described skull & cranial suture morphology
1830 Wilhelm Otto recognised premature fusion as primary cause of cranisynostosis
1851 Virchow described growth restriction in skull perpendicular to the prematurely fused suture, and is enhancement in plane parallel
1910, 1920 Crouzon and Apert noted craniosynostoses as part of syndromes
1950s Moss noted removal of affected suture did not alter abnormal skull growth, therefore abnormal growth was at level of skull base and follows brain development. Changed entire concept of surgery - to complex cranial expansion procedures
1960 Tessier - father of modern craniofacial surgery, including fronto-orbital and midface advancements
1978 Jane & Park - pi procedure for sagittal synostosis
12
Q
What is the aetiology of craniosynostosis?
A
3 possible sites:
Virchow = primary sutural abnormality
McCarthy = dural abnormality - intrinsic suture biology, secondary to osteoinductive properties of dura mater
Moss = abnormality in skull base (exerts abnormal tension)
? Abnormalities of fibroblast growth factor receptors 1,2 & 3 (FGFR)
Primary - defect in mesenchymal layer ossification in cranial bones
Secondary
- Endocrine: hyperthyroidism, Vit D deficiency, renal osteodystrophy, low P, high Ca
- Haematological: bone marrow hyperplasia (sickle cell, thalassaemia)
- Microcephaly (abnormal brain growth)
- in utero compression, hydrocephalus decompression e.g. after VP shunt
13
Q
How is craniosynostosis classified?
A
Classification
- By location of affected suture(s)
- By resultant head shape
- Primary or Secondary
- Syndromic vs non-syndromic
Sagittal = Scaphocephaly (35%)
- keel shaped skull
Coronal (Uni = 15%)
- Unilateral: twisted skull - ant plagiocephaly
- Bilateral: short skull (brachycephaly), compensatory growth upwards (turricephaly/acrocephaly).
- Also associated with upper and mid face hypoplasia, elliptical orbits (Harlequin feature), poorly formed supraorbital ridge
Metopic (5%) = Trigonocephaly
Lambdoid
- Unilateral: Posterior Plagiocephaly
- Bilateral: Brachycephaly
Synostosis of multiple sutures
- Clover leaf skull - Kleeblattschädel
Primary = suture fused prematurely Secondary = early fusion of sutures due to primary failure of brain growth (microcephaly - all sutures fuse)
14
Q
What are the clinical features of synostoses?
A
Primary changes - Abnormal skull shape - Symptoms/signs Raised ICP = Irritable, headache, difficulty sleeping, tense fontanelles, papilloedema, psychomotor retardation, fits 13% of single suture synostoses 40% with multiple sutures
Secondary changes
- Abnormal skull shape
- Harlequin appearance of lateral orbit on AP (superior displacement of the lesser wing of sphenoid)
- Copper beaten, thumb printing and wormian appearance, absent suture line if raised ICP
15
Q
How does positional plagiocephaly differ from synostotic?
A
Positional = distortion of the skull by external forces. Rx conservatively.
Differentiate by:
1. Skull shape
True: Trapezoid
Pos: Rhomboid
- Ear position
True: displaced back
Pos: displaced anterior - Brow and Cheek shape (frontal bossing)
True: contralateral prominence
Pos: ipsilateral prominence - Ipsilateral & contralateral occiput
Both: ipsilateral occipitoparietal flattening
True: contralateral parietal bossing
Pos: contralateral occipital bossing
16
Q
How is positional plagiocephaly managed?
A
All managed non-surgically
Most infants improve with repositioning manoeuvres and physiotherapy for torticollis
US - moulding helmets for severe cases
17
Q
Name some syndromal synostoses
A
- > 70 syndromes associated with craniosynostosis
- Characterised by bilateral coronal synostosis, often with some degree of sagittal synostosis
- Brachycephaly = shortened AP diameter of skull and corresponding enlargement of the bitemporal and biparietal diameter
- Also oxycephaly, scaphocephaly, and turricephaly
Acrocephalosyndactyly type
1) Apert’s syndrome
2) Crouzon syndrome
3) Saethre-Chotzen
5) Pfeiffer
Jackson-Weiss
Carpenter
Beckwith-Wiedemann
18
Q
What is Apert’s syndrome? (Acrocephalosyndactyly type 1)
A
- Eugene Apert 1906 (French Paed)
- 1 in 160 000 live births
- FGFR2 gene mutations
- sporadic, advanced paternal age
- Bicoronal synostosis
- Midface hypoplasia
- Acne
- Small beaked nose
- Class 3 malocclusion
- Cleft palate in 20%
- vertebral fusions C5-6
- low set ears, conductive hearing loss
- Complicated hand deformities – incl. acrosyndactyly (Upton)
o Type 1 – Spade or Paddle Hand +/- bony fusions at P3
o Type 2 – Mitten – thumb fused to central mass (simple) +/- bony fusions at P3
o Type 3 – Rosebud – bony union of thumb to central mass
18
Q
How did Upton classify Apert hands?
A
Spade hand
thumb is foreshortened, radial clinodactyly (delta phalanx of the proximal phalanx)
separate from the index finger
shallow first web space.
complex syndactyly of index, middle and ring fingers because of osseous or cartilaginous union of the distal phalanges.
simple syndactyly of little and ring fingers, complete or incomplete
DIPJ of little finger is well formed and functional
Mitten / spoon hand
simple incomplete or complete syndactyly of the thumb and index ray, without any osseous union, no synechia
large, concave palm
bony union of distal phalanges of the index, middle and ring fingers
simple but complete 4th web syndactyly
Rosebud / hoof hand
tight osseous or cartilaginous union between all 5 fingers
All 5 nailplates are conjoined +/- longitudinal ridges, which indicate separate underlying distal phalanges
thumb is indistinguishable from the index ray
little finger, although joined by a common fingernail, does not have an osseous union at the distal phalanx and remains a simple but complete syndactyly
metacarpal synostosis of little and ring finger rays
19
Q
What is Saethre-Chotzen Syndrome? (Acrocephalosyndactyly type 3)
A
- 1 in 25 - 50000
- TWIST gene, AD
- Bicoronal synostosis
- Low set hair line
- Ptosis
- Small posterior displaced ears
- No hand problems or incomplete syndactyly esp 2nd WS
- developmental delay
20
Q
What is Pfeiffer Syndrome? (Acrocephalosyndactyly type 5)
A
- Rudolf Pfeiffer - German geneticist 1964
- 1 in 100 000
- AD
- FGFR 1&2 gene mutations
- Bicoronal synostosis, turribrachycephaly
- Facial appearance like Aperts
- BROAD THUMBS AND BIG TOES +/- ankylosis of elbows
- normal intelligence
Muenke Syndrome = variant of Pfeiffers
- FGFR3 gene mutation
21
Q
What is Crouzon Syndrome? (Acrocephalosyndactyly type 2)
A
Crouzon Syndrome (Acrocephalosyndactyly type 2)
- Octave Crouzon 1912 (French neurologist)
- AD
- FGFR2 & 3 gene mutations
- 1 in 25 000 live births
- Bicoronal synostosis
- Midfacial hypoplasia
- shallow orbits - ocular proptosis, exorbitism, keratitis
- parrot-beaked nose
- conductive hearing loss
- normal intelligence usu
- HANDS NORMAL
22
Q
What is Jackson-Weiss Syndrome?
What is Patau syndrome?
A
JWS
- AD
- Craniosynostosis
- Broad Halluces
- Fused tarsal and metatarsals
PS
- trisomy 13
- microcephaly
- wide sagittal suture & fontanelles, cutis aplasia congenita (holoprosencephaly)
- micro / anophthalmia, coloboma, retinal dysplasia
- CL/P (60-80%)
- low set ear, conductive hearing loss
- camptodactyly, polydactyly, rocker bottom feet
23
Q
What is Carpenter syndrome?
A
- AUTOSOMAL RECESSIVE
- British physician 1909
- Rare 1 in million
- Various sutures involved, usu scaphocephaly
- Partial syndactyly of the fingers
- DUPLICATE THUMB / SYMBRACHYDACTYLY- - cong heart defects
24
What is Beckwith-Wiedemann Syndrome?
- Overgrowth syndrome
- 85% sporadic, 1 in 15000
- Metopic synostosis, microcephaly
- Macroglossia (90%), gaping mouth, prognathism
- Large prominent eyes
- Large prominent ears, pits / grooves in earlobe
- Large body size
- Visceromegaly
- Midline abdo wall defects (Exomphalos / umbilical hernia, diastasis recti)
- Wilms Tumour, Hepatoblastoma (~10% develop cancer: regular USS screening)
- Neonatal hypoglycaemia
25
How should a patient with craniosynostosis be managed?
Joint clinics, MDT setting
Paediatric neurologist
- evaluate cause and differentiate primary from secondary craniosynostosis
- plot head circumference and growth
Geneticist
- evaluate for associated syndromes
Plastic Surgeon
- evaluate any associated facial deformities
Neurosurgeon
- evaluate primary craniosynostosis and elevated ICP
Paediatrician
- e.g. hyperthryroid etc
26
Pre-operative assessment for craniosynostosis
Observe position of
Forehead
Eyebrows
- downward displacement in coronal
Eyes
- hypertelorism - CF cleft
- hypotelorism - metopic
- exophthalmos - bilat coronal
Nose
- curvature = facial scoliosis - uni coronal, mandibular hypoplasia
Cheeks
Mandibles
- uni/bilat mandibular hypoplasia - hemifacial microsomia
Ears
- ant & inf displacement - skull base synostosis
27
What preoperative imaging is used?
Plain Xray - shows fused sutures
CT 3D - shallow anterior fossa, deformed dystopic orbits, abnormal calvarial contour, and asymmetric cranial base
Cephalometry (using measurements from CT)
MRI -soft tissue
28
What are the indications for surgery?
| What considerations are taken into account?
Indications for surgery
- progressive facial and cranial deformity
- raised ICP / intracranial hypertension
- progressive exophthalmos with risk to vision
- within 1st year (may be recurrent age 5-10, may require midface advancement at 10-15)
- use cell salvage and tranexamic acid to reduce bleeding
- neuro ICU postop, ICP monitoring
Techniques
- Calvarial vault remodelling
- Endoscopic surgery
- patients with facial deformities may require staged surgical approach
29
What are the treatments for synostosis?
Sagittal strip craniectomy
- Rx early isolated sagittal synostosis
- longitudinal strip of bone over suture excised & constriction released
- +/- spring assisted surgery
Fronto-orbital advancement
- Advances frontal part of skull
- Allows anterior skull growth
- Rx usu < 1yr old
Le Fort III Osteotomy
- Corrects midface retrusion
- Advancements limited to ~ 1 cm
Skeletal distraction
- Recent technique
- Osteotomies similar to Le Fort III advancement, a RED frame (rigid external distraction device) fitted, can advance >1cm
Monobloc advancement
- Advances fronto-orbital and Le Fort III segments as one block
- Communication between cranial and nasal cavities → high infection rate
Internal distraction devices
Endoscopic techniques (Jimenez, Barone)
30
What are the complications following surgery?
Death (1-2%) - due to uncontrolled intraop haemorrhage, air embolus, cerebral oedema, resp infection/obstruction, CSF leak and meningitis
Other complications
- optic nerve injury
- persistent CSF leak
- seizures, raised ICP, hypdrocephalus
- plate migration
- infection 2.5% (lower rate in infants c.f. older children)
- facial swelling including orbital
- airway obstruction
- cosmetic disappointment / recurrence of defect (27% of syndromic cases, 6% isolated)
31
What follow-up care is required?
- continue head circumference measurements
- check suture does not refuse
- watch for signs of raised ICP
32
What is the difference between
1. hypertelorism
2. hypotelorism
3. telecanthus
4. pseudo-telecanthus
1. Hypertelorism = ↑ distance between the bony orbits
2. Hypotelorism = ↓ distance between orbits (can be caused by metopic synostosis )
3. Telecanthus = ↑ intercanthal distance (ICD) (dist between bony orbits may be normal)
4. Pseudo-telecanthus = illusion of telecanthus caused by a flat nasal bridge or prominent epicanthal folds.
33
What are the causes of hypertelorism?
1. Median and paramedian facial clefts - Type 1&2
2. Syndromes → Aperts, Crouzon’s, Craniofacial nasal dysplasia
3. Sincipital (frontal / nasofrontal) encephalocoeles
4. Midline tumours e.g. Midline dermoid tumours
34
What is the treatment for hypertelorism?
Box osteotomy
- Rectangular osteotomies made around each orbit, bone bn removed and orbits are moved medially towards each other. Used in patients with isolated hypertelorism & a normal midface width.
Facial Bipartition
- whole facial skeleton is divided vertically in the midline
- central bony segment is removed and two lateral segments containing orbits are moved medially towards each other.
35
What is hemifacial microsomia?
Hemifacial microsomia
- Congenital underdevelopment of one side of the face. Aka first and second branchial arch syndrome and otomandibular dysostosis.
- 1 in 5000 live births
- usually asymmetrical (TCS - symmetrical)
36
What are the hypoplastic craniofacial conditions?
1. Hemifacial microsomia (cleft 7)
2. Treacher Collins (TCS) (cleft 678)
3. Goldenhars (cleft 8)
4. Hemifacial atrophy
37
Tell me about HFM.
- spectrum of morphogenetic anomalies involving the cranial skeleton, soft tissue, and neuromuscular structures derived from the first and second branchial arches
- incidence of 1:5600 live births
- unilateral in 80% of cases
- M:F = 3:2
- R:L = 3:2
- most cases sporadic, 3% 1st degree relatives
- familial - AD & AR, chr 8, 22q, 14q
Pathogenesis theories
1. stapedial artery hematoma during the fourth to eight weeks of gestation
2. failure of neural crest cell development and migration ('mesodermal insufficiency' Stark)
38
What is HFM also know as?
Otomandibular dysostosis (Francois & Haustrate 1954)
1st and 2nd branchial arch syndrome (Stark and Saunders 1962, Grabb 1965)
Oculoauriculovertebral sequence (Gorlin 1956)
Lateral facial dysplasia (Ross 1975)
Craniofacial microsomia (Converse 1979)
39
What is the OMENS plus classification?
```
O
0 Normal orbit
1 Abnormal size
2 Abnormal position
3 Abnormal size and position
```
```
M
0 Normal mandible
1 Hypoplastic mandibular ramus
2 Hypoplastic and malformed mandibular ramus
3 Absence of ramus, glenoid fossa
```
```
E
0 Normal ear
1 Auricular hypoplasia
2 Absence of external auditory canal
3 Absent auricle and malpositioned lobe
```
```
N
0 Normal facial nerve
1 Upper facial nerve involvement (TZ)
2 Lower facial nerve involvement (BMC)
3 All branches affected (TZBMC)
```
S
0 No soft tissue abnormality
1–3 Minimal, moderate, severe soft tissue/muscle deficiency
(Does not include e.g. other CN V, XI, macrostomia or auricular anomalies)
Plus Extracraniofacial abnormalities
40
What classification is used for mandibular malformations in hemifacial microsomia?
The Pruzansky classification of mandibular hypoplasia
Type I
- all components of the mandible are present but hypoplastic
- TMJ present, but cartilage and joint space reduced
Type IIA
- condylar process is cone shaped
- articulation allows hinge but not
translatory mvmt
Type IIB
- no condylar process articulates with temporal bone,
- coronoid process of varying size is present
Type III
- entire mandibular ramus is absent
41
What is the SAT Classification of HFM?
SAT classification
| - skeletal, auricular, and soft tissue involvement
42
What are the goals of reconstruction for HFM?
Anatomical
- construction and reshaping of craniofacial skeleton
- augmentation of soft tissue
- treatment of e.g. auricular malformation.
Functional
- TMJ articulation and occlusion
- facial paralysis
43
What is Goldenhar's syndrome?
- Oculoauriculovertebral sequence
- Variant of hemifacial microsomia with
additional epibulbar dermoids, preauricular skin tags and vertebral anomalies
44
What are the features of Goldenhars syndrome?
```
Upper eyelid coloboma
Epibulbar dermoids
Antimongoloid slant
Preauricular appendices
External auditory meatal stenosis
Middle and inner ear malformations
Vertebral anomalies
Maxillary hypoplasia
Unilateral facial hypoplasia
Aplasia of mandibular ramus and condyle
Macrostomia
Laryngeal abnormalities
Cardiac defect
Cranial anomalies
Small-for-dates
Feeding difficulties
```
45
What are the features of Goldenhars syndrome?
- Hemifacial microsomia
- Epibulbar dermoids
- Vertebral abnormalities
- Craniofacial microsomia : hypoplasia of pinna, TMJ, middle ear, muscles of mastication, parotid
- Vertebral & rib anomalies
- Cardiovascular defects
- CL(P), CP – not a typical feature
- renal anomalies
46
What is the treatment for Goldenhar's syndrome in stages?
< 2 yrs →
Remove auricular appendages
Correct macrostomia with commissuroplasty
+/- Fronto-orbital advancement
2 - 6 yrs →
Distraction of mandibular ramus (Prozansky 3
may require recon w costochondral rib graft)
```
6 - 14 yrs →
Orthodontic treatment
Ear recon
Soft tissue augmentation (implant / free tissue transfer)
Zygomaticoorbital complex reconstruction
```
> 14 yrs →
Bone grafting to deficient areas
Orthognathic surgery
47
What is Nager Syndrome (Acrofacial Dysostosis)?
- AR
- Craniofacial and upper limb abnormalities
- Hypoplasia of orbits, zygoma, maxilla, mandible and soft palate
48
What is hemifacial atrophy (Parry Romberg’s disease)
- Acquired condition ~ 5 yr → late teens
- 95% unilateral, F:M 3:2
- slowly progressive atrophy of soft tissues of 1/2 of face (starts above maxilla, NL fold area)
- process 'burns-out' in 2-10 yrs
- left with unilateral permanent soft tissue deficiency of face
- cause: ? localised scleroderma, abnormal sympathetics
Sites affected
- 'En coupe de sabre' deformity - sc atrophy in a line from chin to malar, eyebrow & forehead
- Skin → localised atrophy, hyperpigmentation, vitiligo
- Hair → pigment change or loss
- Eye → enophthalmos, refractive error
- Iris → pigment change (heterochromia iridis)
- Forehead → a sharp depression, occasionally into the hairline (coup de sabre)
- Cheek → soft tissue atrophy
- Tongue, salivary gland → atrophy
- Skeleton → underlying hypoplasia
Neurological - seizures, trigeminal neuralgia
49
What is the treatment of hemifacial atrophy?
Treatment
- No treatment while condition active and progressive
- Reconstruction when stable for at least 6 months
o Skeletal - Onlay grafts / implants or osteotomies
o Fat and Dermofat grafts
o Temporoparietal fascia and temporalis muscle transfers
o Free tissue transfer → scapular, parascapular, omentum, groin (over correct)
50
What is the treatment of hemifacial atrophy?
Treatment
- No treatment while condition active and progressive
- Reconstruction when stable for at least 6 months
o Skeletal - Onlay grafts / implants or osteotomies
o Fat and Dermofat grafts
o Temporoparietal fascia and temporalis muscle transfers
o Free tissue transfer → scapular, parascapular, omentum, groin (over correct)
51
What is fibrous dysplasia?
- Abnormal proliferation of bone forming mesenchyme (70-80% monostotic)
- Membranous bones of children
- Presents as enlarging mass in maxilla or mandible
- Lesions are osseous rather than fibrous
- elevated ALP, urine hydroxyproline
- Xray: ground glass appearance, expansion . deformity
- MRI (if ?malignant)
Cherubism
o familial polyostotic fibrous dysplasia → mandible and maxilla. May occur as early as 1 yr old.
```
Albright's syndrome (AD)
o Fibrous dysplasia
o Precocious puberty
o Café-au-lait skin lesions
o Tumours of the pituitary gland
```
52
How does facial growth occur?
Facial skeleton is suspended from skull base
Enlow's principle - midface and mandible grow by
- displacement: whole bone mass moves
- remodelling: occurs behind wave of displacement
Moss' functional matrix principle
- osteogenic membranes (e.g. periosteum) react to functional and morphogenic processes acting on them
- e.g. brain growth, pull of muscles of mastication, dentition growth
53
What is the treatment for fibrous dysplasia?
Treatment
Medical
- iv bisphosphonates, calcium & phosphate supplements, vit D
Surgical
- curettage (20-30% recurrence)
- Resection of abnormal areas
- Defects reconstructed with carved calvarial bone grafts
- Radiotherapy may induce malignant transformation (0.5% osteosarcoma)
54
Tell me about craniofacial embryology
- face is recognisable by end of wk 8
- majority of craniofacial anomalies arise in 1st 12wks
- face is derived from 5 facial prominences (frontal nasal process, paired maxillary and mandibular processes)
- they fuse day 46-47
Facial clefting theories
- failure of fusion
- failure of migration of mesoderm into a bilaminar ectodermal membrane → loss of support to overlying epithelial seam
55
What factors contribute to craniofacial anomalies?
Genetic - e.g. FGFR mutations
Radiation - assoc w microcephaly
Maternal infection - toxoplasmosis, rubella, CMV
Maternal health - PKU, DM, vit deficiency, smoking
Encephaloceles - herniation of cranial contents thru skull defect
- 1:5000 births
- Meningocoele - meninges
- Meningoencephalocoele - meninges and brain
- Meningoencephalocystocoele - meninges, brain and ventricle
Encephalomeningocoele
- congenital midline swelling
- herniation from ant cranial fossa via foramen caecum
- assoc w metopic synostosis and hypertelorism
- sites: occipital (80%), parietal, frontal, nasal, nasopharyngeal
- Ix: skull XR, CT/MRI
56
Please define
1. Malformation
2. Dysplasia
3. Disruption
4. Deformation
5. Syndrome
1. Malformation: intrinsic inborn area of fetal developmental process
2. Dysplasia: abnormal organisation of cells into tissue (e.g. Stickler's)
3. Disruption: normal fetus subjected to tissue injury/breakdown (vascular, infection, metabolic)
4. Deformation: abnormal external forces causing secondary distortion/deformity e.g. amniotic band
5. Syndrome: dysplasia affecting 2 or more sites not linked embryologically
57
What are the aims and principles of reconstruction of facial clefts?
Aim: Functional and aesthetic correction of deformities
- Eyelids (to prevent corneal exposure)
- Macrostomia
- Confluent oral, nasal and orbital cavities
Principles
1. Excision of cleft scar tissue and abnormal elements
2. Layered soft tissue closure (local skin flaps) & reattach soft tissue to correct position
3. Delay skeletal recon until child is older,
remove abnormal bone elements and reconstruct with transposition of neighbouring bone or bone grafts
58
Name the oronasal clefts
Tessier 0-3
Cleft 0 (median craniofacial dysraphia)
- Due to failure or delay in closure of anterior neuropore -> midline cleft
- may be assoc with encephalocoeles and hypertelorism
- median cleft lip (absent prolabium), bifid nose, tongue, maxillary midline cleft
Cleft 1 (paramedian craniofacial dysraphia)
Cleft 2 (paranasal)
- cupid's bow → lateral to alar dome
- maxillary alveolar cleft lateral to lat incisor
Cleft 3 (oculonasal)
- MOST COMMON Tessier oronasoocular cleft
- Due to failure of fusion of lateral nasal process with maxillary process
- cupids bow → lacrimal punctum, medial canthal ligament agenesis, colobomata
- cleft from maxilla (lat incisor and canine), secondary palate → nasomaxillary groove → lacrimal bone
59
Name the oroocular clefts
Tessier 4-6
```
Cleft 4 (oculofacial 1 cleft)
- medial to infraorbital foramen
```
```
Cleft 5 (oculofacial 2 cleft)
- lateral to infraorbital foramen
```
Cleft 6
- b/t maxilla & zygoma
- absent lower lashes, lateral coloboma
- 6, 7, 8 = Treacher Collins
60
Name the lateral clefts
Tessier 7-9
Cleft 7 - hemifacial microsomia
- 10% bilateral
- commonest cleft 1 in 3000, M>F
- sporadic, secondary to disruption of stapedial artery
- structures affected centred on line b/t oral commissure and ear: macrostomia, ear defects, facial and trigeminal nerve, parotid
- Runs between zygoma and temporal bone
- bony structures: ascending ramus (mandible), maxilla
Cleft 8
- component of Goldenhar syndrome
- Outwards from the lateral canthus
- b/t zygoma and temporal bone into greater wing of sphenoid (frontozygomatic suture)
Cleft 9
- rarest
- supraorbital rim into forehead (continuation of cleft 5)
- associated with encephaloceles, facial nerve palsy, cranial base abnormalities
61
Name the cranial clefts
Tessier 10-14
Cleft 9-11: Start in supraorbital region, each more medial, assoc with 5, 4, 3 clefts (they add up to 14)
Cleft 10
- middle 1/3 of supraorbital rim
- fronto-orbital encepahlocele displaces eye inferolaterally → hypertelorism
Cleft 11
- medial 1/3 of upper lid and eyebrow, bony cleft lateral to ethmoid → hypertelorism
Clefts 12,13,14
- Cranial extensions of 2, 1, 0 (add up to 14)
- Do not involve orbit, may be assoc with hypertelorism and widening of cribriform plate
Cleft 12
- medial 1/3 of eyebrow
- hypertelorism, telecanthus, enlarged frontal and sphenoid sinuses
Cleft 13
- medial to eyebrow → hypertelorism
- wide cribriform plate, hypertrophied ethmoid cells
Cleft 14
- holoprosencephaly, frontonasal encephalocele, bifid crista galli
Cleft 30
- Median cleft of lower lip and mandible, inferior extension of cleft 0, may go into neck (hyoid bone, sternum).
62
What are the principles of craniofacial surgery?
Good access
Rigid fixation (absorbable plates preferable)
Autologous bone graft - split calvarial (parietal), split rib
Mepore (porous polyethylene, methylmethacrylate, hydroxyapetite
Pericranial / galeal flaps
63
What are the suggested timings for CF surgery?
Marchac (BJPS 1994)
- brachycephaly: 3mths
- others: 9-12mths
Wall (BJPS 1994)
- unless raised ICP or severe exorbitism, operate after 12mths
- both suggest later surgery reduces re-op rates (~5%)
64
When is frontofacial monobloc advancement indicated in infancy?
- only if severe exorbitism in infancy
Risks
- infection
- blood loss intraop
- deformity may return (op <5yrs old)
65
What is the usual treatment algorithm for craniosynostosis with midface hypoplasia (e.g. Apert, Crouzon)?
1. Frontal advancement
2. Le Fort III facial advancement (age 6-12)
(+/- facial bipartition to correct hypertelorism) +/-
3. Le Fort I advancement for correction of bite (age 12-18)
66
What are the key steps in e.g. fronto-orbital remodelling?
- transcoronal zig zag incision, subperiosteal dissection
- burr holes, craniectomy, elevate bone off dura (risk of entering sinuses)
- elevate temporalis, cut and advance frontal bar
- cut barrel staves and out-fracture
- split calvarial bone grafts
- replace bone flaps, fix with absorbable plates, mix bone dust with Tiseel and add to gaps
- close with drains
67
How do you correct sagittal synostosis?
- aim: reduce AP length and increase width
- Sagittal strip craniectomy
- Frontal, parietal and orbital remodelling (barrel stave)
68
How do you correct unicoronal and bicoronal synostosis?
Unicoronal
- Aim: advance and restore supra-orbital rim
- Bilateral fronto-orbital advancement, frontal remodelling
Bicoronal (e.g. Aperts, Crouzons)
- frontal advancement within 1st yr
- mid-face advancement Le Fort III osteotomy age 9-12
- may require secondary Le Fort I osteotomy (risk of causing VPI)
- alternatively: monobloc advancement (Monasterio) but higher risk of infection & need for bone graft
69
How is multiple sutures synostosis e.g. Kleeblattschadel treated?
- Aim: correct exorbitism, exophthalmos, hydrocephalus, mid-face hypoplasia
- urgent cranial vault expansion
- repeat / revisional procedures usually needed
70
How is metopic synostosis treated?
Aim: correct trigonocephaly, hypotelorism
- frontoparietal advancement & remodelling with barrel stave osteotomies
- supra-orbital bar advancement
- hypotelorism self-corrects
71
How is lambdoid synostosis treated?
Aim: correct occipital flattening on affected side - remodel occiput
- occipital bandeau with barrel staving or spiral osteotomy
72
What are the causes of craniofacial asymmetry?
Congenital
- HFM
- unicoronal synostosis
- Beckwith-Wiedemann syndrome
Acquired
- hemifacial atrophy
- lipodystrophy
- DXT in childhood / surgery
- hypoplasia
73
What is the typical Tessier treatment timing?
Neonate - airway (tracheostomy), secondary vision, feeding, hearing issues
6 mths - CP repair
5-6yrs - split calvarial onlay grafts (inferolateral orbit & zygoma)
6rys - soft tissue correction, coloboma, ear recon, macrostomia commissuroplasty, reset hairline / sideburn
6-12 yrs - orthodontics, jaw surgery: Le Fort III maxillary advancement, mandibular sagittal split osteotomy, advancement or distraction
12-18 yrs - Le Fort I advancement, sliding genioplasty
18yrs - rhinoplasty (broad nasal bridge)
74
What is the difference b/t hypertelorism and telecanthus?
What is Tan and Muliken's classification of hypertelorism (1997 PRS)
Treatment
Hypertelorism - inc dist b/t bony orbits
Telecanthus - inc intercanthal dist
Classification
- Frontonasal malformation (median cleft syndrome)
- Craniofrontonasal dysplasia (Cohen syndrome)
- Craniofacial clefts (paramedian)
- Encephaloceles (interorbital)
- Misc: Apert Pfeiffer Noonan
Facial bipartition - removal of central bony segment
Box osteotomy - rectangular osteotomy around each orbit, remove / add bone if needed. Good for asymmetry
75
Miscellaneous HN conditions
1. Craniofrontonasal dysplasia
2. Binder's syndrome
3. Klippel Feil sequence
1. Craniofrontonasal dysplasia (Cohen syndrome) - - unicoronal synostosis, hypertelorism, bifid nasal tip, broad nasal bridge, dry frizzy hair, long grooved nails
2. Binders
- maxillonasal dysostosis, hypoplastic mid-face
- decreased vertical height of maxilla, absent ant nasal spine, class III malocclusion, short flat nose, short columella, acute NL angle, perialar flatness, convex upper lip, shallow philtrum, vertebral anomalies 50%
3. KF
- 1 in 40000, AD variable penetrance
- failure of segmentation of cervical spine esp C2-3, Sprengel's deformity, congenital scoliosis, low hairline, hearing loss 30%, cleft palate 20%, may be feature of other syndromes e.g. Goldenhars
76
4. Cutis aplasia congenita
| 5. Hurler's syndrome
4. Cutis aplasia congenita
- usu sporadic, isolated, 25% multifocal
- absence of midline vertex, sharply demarcated patch
- may be associated with skull defects, exposed dura, sagittal sinus or brain
Rx: usu conservative, dressings and secondary healing
5. Hurlers
- mucopolysaccharidosis (deficient alpha-L-iduronidase
- AR
- gargoylism: coarse features, prominent forehead, corneal clouding, short stature, progressive metal disability, life expectancy 10yrs
Rx - enzyme replacement, haematopoietic stem cell transplant
77
What is the assessment for genioplasty
What are the different types?
Assessment
- medical and orthodontic hx, dentition, occlusion
- Ricketts E line (pogonion - nose tip should lie just anterior to lips)
- chin-nose relationship
- Cephalometrics - Frankfurt plane, pogonion, menton, subspinale, supramentale, nasion
Imaging
- OPG
- Cephalogram
78
What are the different types of genioplasty?
Osseus
- Sliding
- Jumping
- Wedge
- Interpositional
- Reduction
- Centralising (or asymmetric)
Implant
- Snythetic (silicone, medpor, bylon mesh, expanded PTFE, hydroxyapetite)
- Biological - autologous bone
79
What is the technique for implant augmentation?
submental exposure
intraoral exposure
fixed / not fixed
80
What are the complications of genioplasty
```
haematoma
infection
nerve injury (mental, inf alveolar)
malposition
under / overcorrection, asymmetry
```
