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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 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 OBJECTIVES To illustrate the imaging aspects of otomandibular dysplasia through a study of 10 cases. To highlight the contribution of imaging in the preoperative assessment of the lesions of oto-mandibular dysplasia. 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). RESULTS CT revealed skeletal anomalies in all cases variable mandibular hypoplasia (n=10) (table1) temporo-mandibular joint anomalies (n=8) zygoma hypoplasia (n=6) pterygoid hypoplasia (n=4) 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). Table 1 Mandible anomalies Ascending ramus hypoplasia 10 Mandibar condyle 7 Maxillar anomalies TM joint deformity 8 Reduced hight Ear malformations External meatal Middle ear cavity atretic hypoplasia 2 hypoplasia 6 4 absent 7 ossicles atretic 1 Aberrant course of the facial nerve hypoplasic 1 malformed 6 2 3 Others craniofacial anomalies mastoid hypoplasia Number Zygomatic arch hypoplasia 3 6 Styloid Process hypoplasia 3 Orbit anomalies Table 2 2 Soft tissus anomalies Number Mastication muscles hyploasia Parotid gland masseter hypoplasia 8 temporal 7 pterygoid 7 3 absent 3 present 4 Table 3 Case n°1: 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 c d (a,b) 3D bone reconstruction middle ear cavity (arrowhead) with atretic ossicles and external meatal atresia (arrow). reveal mandibular ramus,condyle and coronoid process hypoplasia, zygomatic arch hypoplasia (blue arrow) styloid hypoplasia ( yellow arrow) and reduced high of the maxillar (*) Case n°1 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 Case n°2: 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 d e f (e,f) axial CT scan reveal soft-tissu anomalies: hypoplastic masseter, temporal and pterygoid muscles (arrows) and hypoplastic parotid gland (*). reveal external meatal atresia, agenetic middle ear with hypoplastic and unpneumatized mastoid. Case n°3: 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 (*). Case n°4: 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 (*) Cas n°5: A 6 years old boy a b 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 Case n°6: 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 Case n°6 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) 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. 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. 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) 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. 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. Craniofacial anomalies S. Pruzansky’s 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 Craniofacial anomalies 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 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. 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 Craniofacial anomalies 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. 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 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. Skeletal categories Auricle categories Soft tissue categories S1 = Small mandible with A0 = Normal T1 = Minimal contour defect with normal shape no cranial nerve involvement S2 = Condyle, ramus, and A1 = Small, malformed T2= Moderate defect sigmoid notch identifiable but grossly distorted; mandible strikingly different in size and shape from normal auricle retaining characteristic features S3 = Mandible severely A2 = Rudimentary auricle T3 = Major defect with obvious malformed, ranging from poorly identifiable ramal components to complete agenesis of ramus with hook at cranial and corresponding to the helix 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 A3 = Malformed lobule with orbital involvment with gross posterior recession of lateral and inferior orbital rims rest of pinna absent S5 = The S4 defects plus orbital dystopia and frequently hypoplasia and asymmetrical neurocranium with a flat temporal fossa The skeletal, auricle, and soft tissue (SAT) classification system of HFM Orbit Mandible Ear Facial nerve Soft tissue O0 = Normal M0 = Normal E0 = Normal ear N0 = No facial nerve S0 = No obvious soft involvement tissue or muscle deficiency orbital size position mandible O1 = Abnormal M1 = Mandible and E1 = Mild N1 = Upper facial nerve S1 = Minimal orbital size glenoid fossa are small with a short ramus hypoplasia and cupping with all structures present involvement (temporal and zygomatic branches) subcutaneous/muscle deficiency N2 = Lower facial nerve S2 = Moderate between involvement (buccal, mandibular, and cervical branches) the 2 extremes,S1 and N3 = All branches of S3 = Severe soft tissue M2 = Mandibular ramus is short and abnormally shaped Subdivision A and B are based on relative positions of condyle and TMJ 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 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 deficiency due to subcutaneous and muscular hypoplasmia The orbit, mandible, ear, facial nerve, and soft tissue (OMENS) classification system of HFM 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.