Imaging OF OTOMANDIBULAR DYSPLASIA: ABOUT 10 CASES

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Imaging OF OTOMANDIBULAR DYSPLASIA ABOUT 10 CASES
A.Ben Abdallah, K.Mrad Dali, M.Omezzine,
I.Chaabani, N.Mama, K.Kadri, H.Moulahi,
K.Tlili Radiology service, Sahloul
Hospital MaxilloFacial surgery service, Sahloul
Hospital
HN14
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INTRODUCTION

• Otomandibular dysplasia is a condition in which
  the lower half of one side of the face is
  underdeveloped and does not grow normally.
• It is sometimes also referred to as hemifacial
  microsomia, first and second brachial arch
  syndrome, oral-mandibular-auricular syndrome,
  lateral facial dysplasia,
• or otomandibular dysostosis.
• The syndrome varies in severity, but always
  includes the underdevelopment of the ear and the
  mandible. This is the second most common facial
  birth defect after clefts

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OBJECTIVES

• To illustrate the imaging aspects of
  oto-mandibular dysplasia through a study of 10
  cases.
• To highlight the contribution of imaging in the
  preoperative assessment of the lesions of
  oto-mandibular dysplasia.
  
  

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PATIENTS AND METHODS

• Retrospective study about 10 pediatric cases
• 7 boys and 3 girls,
• Aged from 5 months to 10 years old.
• All patients underwent a computed tomography scan
  (CT).

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RESULTS

• CT revealed skeletal anomalies in all cases
• variable mandibular hypoplasia (n10) (table1)
• temporo-mandibular joint anomalies (n8)
• zygoma hypoplasia (n6)
• pterygoid hypoplasia (n4)
• Soft tissue anomalies (table3) muscle hypoplasia
  were observed in 7 cases and parotid gland
  hypoplasia in 3 cases and agenesic in 3 cases
• Hypoplasia of the tympanic cavity was present in
  7 patients whith ossicular anomaly in 6 cases.
• Other craniofacial anomalies was seen (table2).

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Table 1
Mandible anomalies Mandible anomalies Mandible anomalies Maxillar anomalies Ear malformations Ear malformations Ear malformations Ear malformations Ear malformations Ear malformations Ear malformations Ear malformations
Ascending ramus hypoplasia Mandibar condyle TM joint deformity Reduced hight External meatal External meatal Middle ear cavity Middle ear cavity ossicles ossicles ossicles Aberrant course of the facial nerve
Ascending ramus hypoplasia Mandibar condyle TM joint deformity Reduced hight atretic hypoplasia hypoplasia absent atretic hypoplasic malformed 3
10 7 8 2 6 4 7 1 1 6 2 3
Number Others craniofacial anomalies Others craniofacial anomalies Others craniofacial anomalies Others craniofacial anomalies
Number mastoid hypoplasia Zygomatic arch hypoplasia Styloid Process hypoplasia Orbit anomalies
Number 3 6 3 2
Table 2
Number Soft tissus anomalies Soft tissus anomalies Soft tissus anomalies Soft tissus anomalies Soft tissus anomalies Soft tissus anomalies
Number Mastication muscles hyploasia Mastication muscles hyploasia Mastication muscles hyploasia Parotid gland Parotid gland Parotid gland
Number masseter temporal pterygoid hypoplasia absent present
Number 8 7 7 3 3 4
Table 3
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Case n1 A 2 years old boy
e
a
b
f
(c,d) coronal CT scan shows pterygoid process
hypoplasia (red arrow), abnormal right TM joint
(arrows) with dysplastic condylar process (e,f)
axial CT scan shows hypoplactic middle ear cavity
(arrowhead) with atretic ossicles and external
meatal atresia (arrow).
c
d
(a,b) 3D bone reconstruction reveal mandibular
ramus,condyle and coronoid process hypoplasia,
zygomatic arch hypoplasia (blue arrow) styloid
hypoplasia ( yellow arrow) and reduced high of
the maxillar ()
8
Case n1
c
a
b
Coronal (a,b) and axial (c,d) CT scan show
hypoplasia of muscles of mastication masseter
(arrowhead), temporal (red arrow) and pterygoid
(yellow arrow). It shows also agenesis of the
parotid gland
d
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Case n2 8 year old boy who had malformed left
external ear since birth.
(a)3D bone reconstruction shows left mandibular
and maxillary severe hypoplasia ()with
hypoplastic zygoma arch (arrow).
a
b
c
(b,c) CT scan show an absent condylar process,
hypoplastic condyle with abnormal TM joint
(arrow) and hypoplastic pterygoid process
(arrowhead)
(d) axial CT scan reveal external meatal atresia,
agenetic middle ear with hypoplastic and
unpneumatized mastoid.
d
e
f
(e,f) axial CT scan reveal soft-tissu anomalies
hypoplastic masseter, temporal and pterygoid
muscles (arrows) and hypoplastic parotid gland
().
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Case n3 A 11 years old boy
(a,b) coronal CT scan and 3D bone reconstruction
hypoplastic mandibular condyle with TM joint
dislocation (arrow).
b
a
e
(e)axial CT scan shows minor muscles hypoplasia
(arrow) with normal parotid gland.
c
d
Coronal (c) and axial(e) CT scan agenesis of
external meatal, hypoplastic middle ear cavity,
malformated ossicles (arrow) and hypoplastic
and unpneumatized mastoid ().
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Case n4 A 9 years old boy
Axial CT scan (a,b) and 3D bone reconstruction
(c,d) mandibular condyle hypoplasia (arrow) with
normal ramus. There is an external meatal
agenesis and hypoplastis ossicles (arrowheads).
(e,f) axial and coronal CT scan show
masseter,pterygoid and temporal muscle
hypoplasia (arrows)with hypoplastic parotid
gland ()
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Cas n5 A 6 years old boy
b
a
3D bone reconstruction shows a more dramatic
appearance of asymmetric hypoplasia of the
mandible and hypoplastic zygomatic arch (a,b) CT
scan reveals hypoplastic external meatal , middle
ear cavity and ossicles (arrows)
(c,d) axial CT scan shows musles of mastication
hypoplasia (arrows) agenesis of parotid gland ()
c
d
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Case n6 A 10 years old boy
b
a
c
CT scan and 3D bone reconstruction show a left
hemifacial microsoma which associate hypoplastic
ramus (c,e) , mandibular condyle (b) with
anomaly of TM joint (b) , hypoplastic pterygoid
process( a) and zygomatic arch (e).
d
e
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Case n6
a
b
e
(e) axial CT image shows masseter muscle
hypoplasia with hypoplastic parotid gland
c
d
( a,b,c,d) axial and coronal CT images reveal
agenesis of external meatal (yellow arrow)and
middle ear constituents (red arrows) and show
an aberrant course of the 3rd portion of facial
nerve (arrowhead)
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DISCUSSION

• Hemifacial microsomia is a congenital
  malformation in which there is a deficiency in
  the amount of hard and soft tissue on one side of
  the face. It is primarily a syndrome of the first
  branchial arch,
• It a syndrome involving underdevelopment of the
  temporomandibular joint, mandibular ramus,
  masticatory muscles and the ear
• There may be cardiac, vertebral, and central
  nervous system defects, in addition to
  craniofacial anomalies.

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Discussion

• Otomandibular dysostosis (OMD) is the second most
  common congenital facial anomaly after cleft
  lip/palate with a reported incidence of about 1
  in 5600 live births.
• Males appear to be more frequently affected than
  females (7 boys for 3 girls in our study).
• It is usually unilateral (70) and always
  asymetrical if it exhibits bilaterality.

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Discussion

• The phenotype is highly variable
• The clinical picture varies from slight asymetry
  in the face to sever underdevelopment of one face
  half with orbital implications, a partially
  formed ear or even total absence of the ear.
• In 48 of the cases, the condition is a part of a
  larger syndrome such as Goldenhar Syndrome (when
  epibulbar dermoids and vertebral anomalies are
  seen along with other findings of HFM)

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Discussion

• A panoramic radiograph provides an excellent
  overview of the osseous structures of the
  mandible and maxillofacial complex.
• The relationship of the mandible and maxilla to
  the cranial base can be established initially
  with a lateral cephalometric radiograph.
• Computed tomography (CT) can provide both a three
  dimensional rendition of the soft tissue and an
  image of the under lying bone
• Information on comparative muscle development can
  be assessed through CT or magnetic resonance
  imaging on a case by case basis.

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Imaging findings Craniofacial anomalies

• 1-Mandible
• The most obvious skeletal deformity (all our
  cases),
• The ascending ramus can be absent or reduced in
  height. It was the most common anomaly in our
  study,
• The chin is deviated towards the affected side
• The mandibular condyle may be hypoplastic
• and malformed
• The TM joint deformity can range from mild
  hypoplasia of the codyle with normal joint
  anatomy to a grossly disorganized joint anatomy
  and pseudo-articulation of the condyle at the
  cranial base.

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Craniofacial anomalies
S. Pruzanskys mandible hypoplasia classification
Grade I minimal hypoplasia of mandible Grade II
functioning but deformed TM joint with anteriorly
and mdially dispalced condyle Grade III absence
of the ramus and glenoid fossa
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• 2-Maxillar
• Is also reduced in height, present only in 2
  cases in our study
• Eruption of mandible and maxillary molllars is
  delayed
• 3-Ear
• The meatal atresia and middle ear anomalies are
  almost constant findings (from 66 to 99) (all
  cases),
• The external ear malformations vary from complete
  aplasia to a crumpled, distorted pinna along with
  ear tags
• Supernumerary ear tags may occur anywhere from
  the tragus to the angle of the mouth.
• Middle ear cavity is small and ossicles may be
  absent, hypoplastic and/or malformed
• The mastoid is always hypoplastic and
  unpneumatized

Craniofacial anomalies
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Craniofacial anomalies

• 4-Other craniofacial bones anomalies
• The zygoma arch may be decreased in length or
  absent (60 in our study)
• The mastoid process can be hypoplastic
• The styloid process may be short or absent ,
  present in only 3 patients
• The orbit may be reduced in dimensions and
  frontal bone can be flattered
• Clinical microphthalmia or anophthalmia has been
  reported and the ipsilateral eye may be at a
  lower level than that on the opposite side.

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Craniofacial anomalies

• 5-Extraskeletal anomalies
• Hypoplasia of facial muscles, such as the
  masseter, temporal, pterygoid, and those of
  facial expression on the involved side can be
  observed (80 in our study)
• Hypoplasia or aplasia of the parotid gland
• Narrowing of the palpebral fissure occurs on the
  affected side in about 10 of patients
• A coloboma of the upper eyelid is frequently
  encountered
• Associated cleft lip and/or palate is found in 7
  of patients

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• Epibulbar dermoids may be seen in Goldenhar
  Syndrome
• Hypoplasia and / or paresis of palatal muscles
  and pharynx, alongwith tongue musculature is also
  reported
• 6-Cranial nerve anomalies
• Sensorineural hearing loss and facial nerve
  dysfunction are common
• Aberrant course of the facial nerve,
• Total or partial hypoplasy of the nerve.
• Only 3 patients have aberrant course of the
  facial nerve without nerve paralysis.

Craniofacial anomalies
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Imaging findings Extrafacial anomalies

• Cranial CT scan can revel hypoplasia of cerebrum
  and corpus callosum as well as hydrocephalus
• Approximately, 50 of patients have congenital
  heart disease
• 40 to 60 of HFM patients exhibit
  occipitalization of the atlas, cuneiform
  vertebra, cervi cal complete or partial
  synostosis of 2 or more vertebrae, supernumerary
  vertebrae, spinal bifida, and anomalous ribs.
• No extrafacial anomalies were seen in our study

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Imaging findings classification

• The wide spectrum of anomalies associated with
  HFM has made systematic and inclusive
  classification difficult. Classification of the
  disease aids in diagnosis, treatment planning,
  prognostic predications, and data evaluation.
• the 2 popular classification systems used for
  HFM, namely, the skeletal, auricular, and soft
  tissue (SAT) system, and the orbit, mandible,
  ear, nerve, and soft tissue (OMENS) system.

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Skeletal categories Auricle categories Soft tissue categories
S1 Small mandible with normal shape A0 Normal T1 Minimal contour defect with no cranial nerve involvement
S2 Condyle, ramus, and sigmoid notch identifiable but grossly distorted mandible strikingly different in size and shape from normal A1 Small, malformed auricle retaining characteristic features T2 Moderate defect
S3 Mandible severely malformed, ranging from poorly identifiable ramal components to complete agenesis of ramus A2 Rudimentary auricle with hook at cranial and corresponding to the helix T3 Major defect with obvious facial scoliosis, possible severe hypoplasia of cranial nerves, parotid gland, muscles of mastication eye involvement clefts of face or lips
S4 An S3 mandible plus orbital involvment with gross posterior recession of lateral and inferior orbital rims A3 Malformed lobule with rest of pinna absent
S5 The S4 defects plus orbital dystopia and frequently hypoplasia and asymmetrical neurocranium with a flat temporal fossa A3 Malformed lobule with rest of pinna absent
The skeletal, auricle, and soft tissue (SAT)
classification system of HFM
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Orbit Mandible Ear Facial nerve Soft tissue
O0 Normal orbital size position M0 Normal mandible E0 Normal ear N0 No facial nerve involvement S0 No obvious soft tissue or muscle deficiency
O1 Abnormal orbital size M1 Mandible and glenoid fossa are small with a short ramus E1 Mild hypoplasia and cupping with all structures present N1 Upper facial nerve involvement (temporal and zygomatic branches) S1 Minimal subcutaneous/muscle deficiency
O1 Abnormal orbital size M2 Mandibular ramus is short and abnormally shaped Subdivision A and B are based on relative positions of condyle and TMJ E1 Mild hypoplasia and cupping with all structures present N1 Upper facial nerve involvement (temporal and zygomatic branches) S1 Minimal subcutaneous/muscle deficiency
O1 Abnormal orbital size M2 Mandibular ramus is short and abnormally shaped Subdivision A and B are based on relative positions of condyle and TMJ E1 Mild hypoplasia and cupping with all structures present N2 Lower facial nerve involvement (buccal, mandibular, and cervical branches) S2 Moderate between the 2 extremes,S1 and S3
O1 Abnormal orbital size M3 Complete absence of ramus, glenoid fossa, and TMJ. Submental vertex views were used to distinguish mandibular type 2A from type 2B. Type O, an apparently normal mandible has not been included in previous classification systems E1 Mild hypoplasia and cupping with all structures present N3 All branches of facial nerve affected. Other involved nerves were also analyzed, eg, trigeminal N5 (sensory), hypoglossal N12 remaining cranial nerves are signified by the appropriate number in superscript S3 Severe soft tissue deficiency due to subcutaneous and muscular hypoplasmia
The orbit, mandible, ear, facial nerve, and soft
tissue (OMENS) classification system of HFM
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CONCLUSION

• The modern imaging opened a possibility of
  precise exploration of oto-mandibular dysplasia
• The techniques of browsing by CT scan and the
  software of image processing allow to carry out a
  true anatomical dissection of the whole of these
  malformative syndromes
• The SAT and OMENS classification systems allows
  to delineate the condition of OMD to provide a
  rational basis for treatment choice.