Download FAVS

April 13, 2018 | Author: Anonymous | Category: , Science, Health Science, Orthodontics
Share Embed


Short Description

Download Download FAVS...

Description

1 FACIOAURICULAR VERTEBRAL SYNDROME

INTRODUCTION  First and second branchial arch syndrome  Characterised by varying degrees of regional hypoplasia of temporo-mandibular and pterygo-mandibular complexes (skeletal and neuro-muscular structures).  Craniofacial microsomia is a widespread disorder involving the temporal bone, middle and external ear, mastoid process and base of the skull. Soft tissue hypoplasia is often apparent on the affected side. Condylar deformity is the hallmark.  Goldenhar syndrome is now considered a part of the continuous spectrum rather than a distinct variant; it is characterized by the additional features of 1. vertebral anomalies 2. rib deformities 3. epibulbar dermoids

Incidence  Incidence: between 1 in 4000 and 1 in 5600 live birth  second most common congenital craniofacial malformation, after cleft lip and palate.  M>F, 3:1  Bilateral in 30%  R>L  Increased risk with diabetic mothers Pathophysiology  sporadic, nongenetic disorder except in a few patients.  Probably due to some intra-uterine insult.  Theories: 1. vascular hematoma of the stapedial artery, the temporary blood supply to the primordia of the 1st and 2nd arches. (possibly induced by teratogens such as thalidomide). 2. deficiency in migration of neural crest cells, deficiency of mesodermal formation, or defective interaction between neural crest cells and mesoderm  Association with CHARGE (iris coloboma, heart anomaly, atresia [choanal], retardation [mental and growth], genital anomaly, ear anomaly) also thought to represent neural crest/mesodermal formation/migration deficiencies.

Clinical and pathological features  Hemifacial microsomia encompasses a wide spectrum of deformities all having in common the three major features  Characteristically heterogeneous nature: varies in extent and degree.  3 major features: auricular, mandibular and maxillary hypoplasia.

2  The auricular hypoplasia may range from ear tags(seen any where along the cheek from the lateral commisure to the ear) to microtia or anotia  Mandible may range from mild reduction in size to marked hypoplasia with absence of glenoid fossa and complete aplasia of the ascending ramus  Correlation exist between the severity of the ext ear deformity and the development of the mandible and the development of the middle ear structures  Hypoplasia also involves adjacent anatomical structures: middle and external ear; mandible; zygoma; maxilla; pterygoid processes; temporal bone, including the mastoid; the facial nerve and muscles of expression; the trigeminal nerve and muscles of mastication; other cranial nerves; other muscles including those of the palate and the tongue; the parotid; the floor of the nose; the eye and the subcutaneous tissues and skin.  The facial palsy is correlated with the severity of the deformity  Macrostomia, a lateral facial cleft (7) and a 1st branchial cleft sinus can occur but not necessary for diagnosis.  Development of the branchial arches is interlinked with the development of the chondrocranium and membranous skull. Anomalies of the branchial arches can therefore be associated with deformities of the cranial bones which can be extensive.  In severe forms, all the structures derived from the 1st and 2nd branchial arches are abnormal, whereas in less severe forms, either the ear or the jaw is predominantly abnormal.  Formes frustes (microforms) are more common than generally acknowledged.  Multiple ocular and adnexal findings have been associated with patients with hemifacial microsomia and the epibulbar dermoid is one of the markers of goldenhars syndrome Classification OMENS-Plus system  five major craniofacial manifestations of hemifacial microsomia (orbit, mandible, ear, nerve, and soft tissue) are assessed. PLUS = extracranial anomalies  Each anatomic abnormality is graded from 0 to 3.  Orbital grading - based on the size and position of the orbit 0. = normal 1. = abnormal size 2. = abnormal position 3. = abnormal size and position  Mandibular grading - based on Kaban modification of the original classification by Pruzansky 1. = Mild hypoplasia of the ramus while the body of the mandible is minimally affected. 2. = condyle and ramus are small, the head of the condyle is flattened (a) glenoid fossa anatomically acceptable compared with opposite temporomandibular joint or

3 (b) temporomandibular joint displaced anteriorly, medially, or inferiorly with a severely hypoplastic condyle 3. = ramus is reduced to a thin lamella of bone or is completely absent. There is no evidence of a temporomandibular joint.  External ear grading - based on that of Meurman 0. = normal 1. = mild hypoplasia and cupping with all structures present 2. = absence of external auditory canal with variable hypoplasia of the concha 3. = malpositioned lobule with absent auricle, lobule remnant inferiorly and anteriorly displaced).  Facial Nerve involvement is categorized according to the division of the nerve involved 0. = normal 1. = upper facial nerve involved 2. = lower facial nerve involved 3. = all branches involved).  Soft-tissue grading is based solely on subcutaneous and apparent muscular deficiency 0. = no obvious deficiency 1. = minimal deficiency 2. = moderate deficiency 3. = severe deficiency).

In those patients with bilateral deformities, the two sides are classified separately David David uses the SAT system - Skeletal, Auricular and Tissue (soft) deficiencies

4 Diagnosis  there has been no agreed minimum clinical criteria for the diagnosis of hemifacial microsomia.  Cousley and Calvert (BJPS1995) suggested useful guidelines of minimal diagnostic criteria for the diagnosis of hemifacial microsomia based on the premise that either mandibular or ear defects are mandatory features, and they accordingly proposed two categories. 1. First, a diagnosis of hemifacial microsomia may be confidently made if both mandibular and ear defects are present. 2. If only one or the other is present, a diagnosis of hemifacial microsomia may be assumed if either two or more indirectly associated anomalies or a positive family history is present.

1. Jaw Deformity  The most conspicuous deformity of craniofacial microsomia is hypoplasia of the mandible on the affected side.  Typically the ramus is short or virtually absent on the affected side. The body of the mandible therefore curves upwards posteriorly and is longer on the affected side. The gonial angle is increased. The chin is deviated to the affected side. Usually the opposite side is also abnormal too.  The condyle is always abnormal (hypoplastic), even in the most minor cases (a pathognomonic feature). With greater degrees of severity, both the condyle and the ramus may be absent.  Clinically, the hypoplasia may be subtle with only a mild occlusal slant (up on the affected side) or the mid-incisor point of the lower jaw being slightly off to the one side.  With growth, facial asymmetry increases, ie, the deformity is progressive.  The floor of the nose, maxillary sinus and the base of the skull may follow the occlusal cant.  Teeth often crowded.  Cross bite occurs because with growth, the condyle lies medially.

2. Orbit  Orbital abnormalities are a manifestation of hypoplasia of the entire cranio-orbitozygomatic complex, with the zygomatic complex being the central component involved.  This results in secondary growth restriction on the adjacent orbit, glenoid fossa, and squamous temporal bone.

3. Other Skeletal Deformities

5  Craniofacial bones, other than the mandible and maxilla can be involved: tympanic and mastoid parts of the temporal bone; styloid process frequently shorter and smaller; frontal bone flattening.  The petrous part of the temporal bone (contains the middle ear) is often spared.  Vertebral anomalies (10%): hemi-vertebrae causing secondary scoliosis, kyphosis, fused vertebrae, spina bifida.  Rib anomalies.

4. Muscles of Mastication  Masseter, temporalis and medial and lateral pterygoids may be deficient.  Soft-tissue deficiency and hypoplasia of the muscles of mastication are intimately associated with the degree of mandibular deformity  According to Moss’s theory of a functional matrix (1968), bone grows in response to its functional requirements, ie the soft tissue affects bone growth by the forces it places on the bone.  Absent pterygoids contribute to mandibular deviation to the affected side on mouth opening. 5. Auricular Deformity  Ear abnormalities are a major manifestation of the syndrome.  presence of a severely affected ear increases the likelihood of a more severely affected mandible being present.  Hearing function does not correlate well with grade of external ear defect, but does correlate with severity of mandibular defect.  Type of hearing loss not always conductive –sensorineural loss in 10%  Need for audiometry in all patients  Tomography (and CT) need to be done to determine middle ear morphology.  The opposite ear needs to be evaluated too.  Ear reconstruction is as for other causes of microtia.

6. Cerebral Anomalies  Wide variety: ipsilateral cerebral hypoplasia, hypoplasia of the corpus callosum, hydrocephalus (both communicating and obstructive), intracranial lipoma and unilateral hypoplasia of brain stem and cerebellum.  Also: mental retardation (5-15%), epilepsy.

7. Cranial Nerve Anomalies (20-45%)  Multiple cranial nerves can be affected. Arhinencephaly to less extensive forms which may involve any of the cranial nerves.  The commonest cranial nerve involved is the facial nerve

6  degree of external ear deformity, rather than other bony or soft-tissue defects, is a predictor of seventh nerve involvement.  Remains unclear whether facial nerve dysfunction is caused by 1. an aberrant pathway of the nerve in the temporal bone 2. hypoplasia of the intracranial portion of the facial nerve 3. a manifestation of facial muscle agenesis 8. Macrostomia/Facial cleft  Atypical cleft no 7  Failure of mesodermal migration or merging to obliterate the gooves between the maxillary and mandibular prominences during week 4-5  Varies from minimal lateral displacement of commissure to complete cleft of face  Cheek deformity always accompanies a muscle defect 9. Soft Tissue Anomalies  Often generalised soft tissue hypoplasia of skin, subcutaneous tissue and facial muscles. The musculature of the soft palate and of the tongue may be affected.  palatal deviation to the normal side  10-15% have cleft lip/palate (mostly ipsilateral)  epibulbar dermoids  benign congenital tumors that contain choristomatous tissue (tissue not found normally at that site) - epidermal appendages, adipose and lacrimal gland tissue, smooth and striated muscle, cartilage, brain, teeth, and bone  2 theories 1. early developmental error resulting in metaplastic transformation of the mesoblast between the rim of the optic nerve and the surface ectoderm. 2. Another proposed mechanism is sequestration of the pluripotential cells during embryonic development of the surrounding ocular structures.

Examination 1. Begin with forehead and the orbit and these are compared for symmetry with the opposite side 2. globe evaluated for epibulbar dermoids and extraocular muscles noted

7 3. 4. 5. 6. 7. 8.

extent of auricular deformity is noted, external auditory meatus facial nerve evaluated chin deviation noted presence or absence of TMJ palpated intraoral examination for cleft and uvula deviation get child to bite on determine occlusal tilt and type a. most pts have class I relationship in spite of marked unilateral hypoplasia of the maxilla and mandible on the affected side 1. assess hearing – average hearing loss of 50 Db 2. assess for VPI as 1/3rd have VPI and palatal movement problems INVESTIGATIONS 1. X rays: facial views, cephalograms, CT head/face, MRI 2. Audiology

DIFFERENTIAL DIAGNOSIS  Bilateral form must be differentiated from Treacher Collins (Irregular AD inheritance with variable penetrance). Craniofacial microsomia has defects of the mandibular ramus and facial paralysis.  Postnatal trauma or infection of the mandibular condylar cartilage can result in impaired growth not only of the mandible, but also of the whole craniofacial osseous complex. Soft tissues are spared. No temporal bone involvement.  Severe orbito-facial clefts: Patients lack the condylar deformity.

Prognosis  Mulliken (PRS 2000)  found that angle piriform rim, maxillary occlusal plane, and intergonial angle increased with serial measurements in 67 patients with untreated hemifacial microsomia  demonstrated that hemifacial microsomia is progressive and underscores the importance of early surgical correction of mandibular asymmetry in this disorder.

TREATMENT  Multidisciplinary team approach best.  Geneticist  Paediatrician  Social worker  ENT  Dental

8 Timing  Most believe that surgery should be performed when the child is 5-6 years, rather than delaying until facial growth is complete.  mandible is usually corrected first in the hope that this will unlock the growth potential of the functional matrix.  Two critical variables are the age of the patient and the extent of the defect.  The more extensive the defect, the greater will be the surgery required and the sooner it should be commenced.  Early surgery during infancy is dictated by airway compromise (ie laryngomalacia) Surgical goals 1) normalizing the occlusal tilt- symmetry of the occlusal plane is necessary to prevent problems with the opposite TMJ 2) reconstruct the TMJ if absent 3) auricular reconstruction Surgical sequence Infancy 1. Airways a. Positioning, trachestomy 2. Feeding difficulties a. gastrostomy Age
View more...

Comments

Copyright © 2017 HUGEPDF Inc.