First and second branchial arch syndromes: multimodality approach

First and second branchial arch syndromes: multimodality approach Poster No.: C-3402 Congress: ECR 2010 Type: Educational Exhibit Topic: Pediatric Authors: T. Laswad, L. Alamo, E. Sengen, D. Fournier, B. Jacques, J. 1 1 2 2 2 1 1 2 2 Moreau, F. Gudinchet ; Sion/CH, Lausanne/CH Keywords: otomandibular dysplasia, Mandibulofacial Dysostosis, Pierre Robin Syndrome DOI: 10.1594/ecr2010/C-3402 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 38

Learning objectives The purpose of this educational exhibit is to review a wide spectrum of first and second branchial arch syndromes (BAS), among them hemifacial microsomia, mandibulofacial dysostosis, branchio-oto-renal syndrome, Pierre Robin sequence and Nager acrofacial dysostosis, to demonstrate the role of different imaging modalities (orthopantomogram, lateral and posteroanterior cephalometric radiographs, CT and MRI) in the diagnosis and to emphasize the importance of the systemic use of multimodality imaging approach for precising the grading of these syndromes, preoperative planning of different reconstructive surgical instrumentations and follow-up during treatment. Background First and second branchial arch syndromes (BAS) manifest as combined deficiencies of tissues and hypoplasias of the face, external ear, middle ear, maxillary and mandibular arches. They represent the second most common craniofacial malformation after cleft lip and palate [1]. Bilateral anomalies of hemifacial microcosmia are present in 30% of these patients [2] Extended knowledge of the embryology and anatomy of each branchial arch derivatives is mandatory in the diagnosis and grading of different BAS lesions and in the follow-up of postoperative patients. A retrospective study of a total 24 children referred or treated in our institution for facial and branchial arch lesionswas was carried out over a period of five years. Many new complex surgical approaches and instrumentations have been designed by maxillofacial surgeons to treat often extensive maxillary, mandibular, external and internal ear deformations. Page 2 of 38

Various imaging techniques such as plain x ray, ultrasound, CT and MRI have been proposed to investigate and follow these lesions with their own advantages and drawbacks. Embryology: The branchial apparatus consists of branchial arches, pharyngeal pouches, branchial grooves and branchial membranes[1]. Neural crest cells are pluripotent cells that are formed from the margins of the neural folds during neurulation and migrate in several domains of the embryo. In the developing head, the cephalic neural crest cells migrate from the hindbrain into the branchial arch system, and interact with epithelial and mesodermal cells leading to the development of craniofacial bones, cartilages and connective tissues [1, 3]. The first branchial arch is involved in the development of the face and muscles of mastication which are dependant on the motor root of the trigeminal nerve (V) [4]. During the 4th to 8th week of gestation, the frontonasal prominence gives rise to the median facial structures (Fig. 1). The paired maxillary and mandibular prominence develop into the lateral facial structures (Fig. 2 and 3). The second branchial arch enlarges during the 5th week, forms the mandibular prominence and is engaged in the development of muscles of facial expression which are dependant on the facial nerve (VII). Therefore, Both arches will develop into nerves, muscles, ligaments and skeletal structures, as shown in Table 1 [1, 4]. Congenital malformations may appear during transformation of the branchial apparatus into adult structures. Any structure derived from the first and the second branchial arches can be affected [5]. Classification: The wide spectrum of otomandibular dysplasias (BAS) makes them difficult to classify, but these deformities can be broadly considered as being skeletal, auricular and soft tissue. Several methods of classification and nomenclature systems have been proposed to categorize different craniofacial anomalies. Tessier [6] described an anatomical classification system whereby a number is assigned to each of the malformations according to its position relative to the sagittal midline. OMENS system, proposed in 1991 [7] includes 5 of the major craniofacial manifestations and allows independent grading of the dysmorphic features. In this system, each anatomical abnormality is graded from 0 (normal) to 3 (most severe. Five distinct dysmorphic manifestations are described by this acronym: O, orbital asymmetry; M, mandibular hypoplasia; E, auricular deformity; N, nerve involvement and S, soft tissue deficiency ),Table 2. Table 3 describes the most common otomandibular anomalies with their synonyms and associated multisystemic abnormalities. Page 3 of 38

Images for this section: Fig. 1: Embryo at 28±1 day. Illustrating the progressive stages of the development of the human face. The first branchial arch formes the frontonasal and maxillary Page 4 of 38

prominences. The second branchial arch enlarges during the 5th week, forms the mandibular prominence. Fig. 2: Embryo at 40±1 day. Illustrating the progressive stages of the development of the human face.the first branchial arch formes the frontonasal and maxillary prominences. The second branchial arch enlarges during the 5th week, forms the mandibular prominence. Page 5 of 38

Fig. 3: Fetus at 14 week. Illustrating the progressive stages of the development of the human face. The first branchial arch formes the frontonasal and maxillary prominences. The second branchial arch enlarges during the 5th week, forms the mandibular prominence. Page 6 of 38

Fig. 4: Table 1: Structures derived from branchial arch components. Page 7 of 38

Fig. 5: Table 2: OMENS classification system. Page 8 of 38

Fig. 6: Table 3: Most common branchial arch syndromes (oto-mandibular anomalies). Page 9 of 38

Fig. 7: Table 3 cont: Most common branchial arch syndromes (oto-mandibular anomalies). Page 10 of 38

Imaging findings OR Procedure details Imaging Findings : Lateral cephalometric radiographs and orthopantomograms combine the advantage of the availability, low cost and and low radiation dose. They usually depict the size and shape of the face, orbit and mandible (Fig. 11a-d), and allow the grading according to the OMENS classification system (Table 2). These two techniques allow an accurate postoperative follow-up and monitoring of bone growth under mono or double distractor treatment (Fig. 16 and 18). Axial and 3D CT imaging permit an accurate description of craniofacial complexes of BAS. Axial images are important to study the skull base configuration, external auditory canal and middle ear anomalies (Fig.8), inner ear abnormalities (Fig.9), middle ear anomalies (e.g abnormal shape and malposition of ossicles), external auditory canal narrowing or atresia, ear pinna atresia or hypoplasia and temporomandibular joint abnormalities. However, we encountered two problems 3D CT images. Movement artefacts in some cases resulted in unsharpness of axial images with deformities of 3D VRT images. Moreover, in one patient with hemifacial microsomia associated with KlippelFeil syndrome, 3D VRT images overestimated occipito cervical C0-C1 assimilation by showing bilateral fusion between occipital condyles and the posterior arch of the atlas while 2D coronal and sagittal thin section reconstructions showed only right side C0-C1 assimilation (Fig 11 and 12). In fact, depending only on 3D volume rendering techniques could be detrimental as the image information depend on the selected Hounsfield Units threshold for structures reconstruction and visualization which can lead to overestimations or underestimations of bone diseases, like occipito cervical assimilation and craniosynostosis. Hemifacial Microsomia (Goldenhar Syndrome, First Branchial Arch Syndrome, Second Branchial Arch Syndrome, Otomandibular Dysostosis, Oto-Auriculo-Vertebral (OAV) Complex) Hemifacial microsomia (HFM) is a craniofacial disorder characterized by a wide spectrum of anomalies, including unilateral mandibular hypoplasia, conductive hearing loss due to external and middle ear deformities as well as vertebral anomalies. HFM is the second most facial birth defect after cleft lip and palate, and may be linked with the VATER sequence as well as cerebral and epibulbar lipomas and dermoides (Fig 10). Page 11 of 38

Any structure derived from the first and second branchial arches may be involved (Table 3). Figures 1, 2, 3, 7, 8 and 9 demonstrate imaging findings of HFM. Mandibulofacial Dysostosis (Treacher Collins, Franceschetti-Zwahlen-Klein Syndrome, Berry-Treacher Collins Syndrome, Franceschetti's Syndrome I, Thomson Complex, Berry Syndrome) Mandibulofacial dysostosis (MFD) occurs in 1/ 50'000 live births and is an autosomal dominant syndrome. About 60% of patients are new mutations. MFD is related to the TCS gene on chromosome 5q32-q33.1. The multiple anomalies associated with MFD are summarized in Table 3. The principal clinical manifestations of MFD are an hypoplasia of the malar bone and of the mandibular ramus and condyle, with an associated antimongoloid slant of the palpebral fissures due to orbito-zygomatic malformation (Fig. 4 and 5). Deformity or absence of the EAC and conductive hearing loss are frequent. Differentiation from HFM may be difficult with overlapping features, but MFD mandibles are bilateral and symmetric with a greater frequency of lid colobomas and skin tags is encountered in MFD patients. Pierre Robin Sequence ( Pierre Robin Syndrome, Robin Anomaly, Pierre Robin Complex) Pierre Robin Sequence (PRS) has no known genetic pattern. Girls are more affected than boys (Female/Male ratio: 3/2). PRS occurs in about 1/8'500 live births. The main clinical features are micrognathia, glossoptosis and cleft palate. The anomalies associated with PRS are summarized in Table 3. The main imaging findings are: global hypoplasia of the mandible (Fig. 6), obtuse mandibular angle, cleft palate. Plain x-rays may show skeletal anomalies such as amelia, congenital amputations, syndactilies, clubfoot, congenital hip dislocation, rib and scapulae anomalies. Some features of the VATER complex may also be associated. Branchio-Oto-Renal Syndrome ( Ear Pits-Deafness Syndrome, BOR Syndrome, Melnick-Fraser Syndrome ) BOR syndrome occurs in about 1/40'000 live births and 2% of profoundly deaf children. The syndrome is autosomal dominant with variable expressivity and penetrance. Page 12 of 38

The anomalies associated with BOR are summarized in Table 3. BOR patients are characterized clinically by ear anomalies, preauricular pits, hearing loss and renal dysplasia. Temporal bone CT scan using thin slices and 2D or 3D reconstructions allows the assessment of the external ear abnormalities the status of the middle ear cavity, the absent or dysplastic and rudimentary ossicles or inner ear anomalies such as microcochlea. Nager Acrofacial Dysostosis Syndrome (AFD Nager, Preaxial Acrofacial Dysostosis) AFD Nager is a sporadic or familial rare variant of MFD. AFD Nager combines many features of MFD, with mandibular and malar hypoplasia, dysplastic ears, antimongoloid slant of the palpebral fissures and deformity or absence of the EAC and conductive hearing loss with limb abnormalities. The limb anomalies of AFD consist mostly in hypoplasia of the radial aspect of the hand, deformed forearm, limitation of elbow extension. Some features of the VATER complex may also be associated. Plain X-rays may demonstrate the radial hypoplasia or aplasia and hypoplasia of the thumb. The same imaging approach as in patients with MFD seems adequate due to the clinical overlapping of the syndromes. Surgical Techniques : Different types of distraction osteogenesis have been advocated as an effective technique in the management of craniofacial deformities [8]. The peculiarity of this technique is that the bone lengthening achieved is accompanied by a simultaneous expansion of the surrounding soft tissue envelope, which contributes to the stability of the reconstruction and lessens the risk of relapse [9]. The usual growth rate for the mandible is 1 mm per day and on the middle third of the face (maxilla, orbit ) not more than 0.3 mm per day. The simultaneous distraction of the maxilla and the mandible has already been described, using a Le Fort I osteotomy and the ascending ramus osteotomy [10]. However, one single distractor on the ascending ramus was used to distract the mandible and the maxilla using a maxillomandibular fixation. Page 13 of 38

In order to reduce intermaxillary inconvenients for the patient (feeding problems and loss of weight, potential respiratory distress, etc..), a new technique of independent distraction of the maxilla and the mandible, each of them equipped by their own distractor, was described by our maxillofacial team in a recent publication [9] (Fig.13 and 14). A consolidation phase of 6 to 8 weeks is needed to allow the distracted callus to calcify and the new bone to remodel, after which the device is removed through the same incision as before (Fig. 15, 16 and 17). CT scans can help to identify contraindications to surgical procedure such as sever hypoplasia or total absence of mandibular ramus. CT is also mandatory in defining which type of surgical procedure to be used, for example, patients with mild form of hemifacial microsomia need conventional maxillary and mandibular osteotomies. In patients with external ear aplasia, uni or bilateral, replacement of the ear can be achieved with an epithesis retained by endosseous implants (Fig. 18 and 19). The same proceeding can be used in children affected by ossicular chain malformation in order to retain an auditive amplificator called BAHA (Bone Anchored Hearing Aid), (Figure 20). Figures: Figure 1: 16 year-old girl with left side hemifacial microsomia. lateral cephalometric radiograph shows asymmetrical mandibular angles (arrows). Figure 2: Same patient. The Orthopantomogram shows the hypoplasia of the left ascending ramus of the mandible and the coronoid process. Figure 3: Same Patient. 3D volume rendering CT: Inferior lateral view of the left pathological side with the hypoplasia of the ascending ramus and malformation of the coronoid process. Figure 4: Mandibulofacial dysostosis ( Treacher Collins syndrome). Lateral cephalometric radiograph shows hypoplasia of the malar bone, mandible and the mastoid. Note the metallic structures for the retention of ear epithesis. Figure 5: Mandibulofacial dysostosis ( Treacher Collins syndrome). lateral view 3D volume rendering CT demonstrates hypoplasia of the malar bone and mandible (ascending ramus and condyle). Note also, the orbito-zygomatic malformation. Page 14 of 38

Figure 6: Pierre Robin syndrome. 3DCT VRT, Lateral view showing a retrognathism with mandibular hypoplasia. Note the global hypoplasia of the mandible without dysplasia. Figure 7: Temporal bone abnormality: Note abnormality of right malar bone with hypoplasia of zygomatic arch as well as dysplasia of right mastoid bone. Note also, right side muscular atrophy of masseter and pterygoid muscles. Figure 8: External and middle ear abnormalities: 16 year old girl with right hemifacial microsomia. Axial CT depicts dysplasia of right tempanic cavity with complete absence of right side middle ear ossicles associated with hypoplasia of mastoid air cells. Note also, the external ear anomaly. Figure 9: Inner ear abnormalities: Right side internal auditory canal hypoplasia in comparison with the normal left side in this patient with right hemifacial microsomia. Figure 10: Associated abnormalities detected by axial CT depicted a Lipoma of corpus callosum in a 15 years old girl with Goldenhaar syndrome. Figure 11: 3D volume rendering techniques could lead to overestimations or underestimations of bone diseases depending on the selected Hounsfield Units threshold used. A 29 year old boy with hemifacial microsomia and Klippel-Feil syndrome. 3D VRT images showed bilateral assimilation between occipital condyles and the posterior arc of the atlas. Figure 12: However, thin section coronal and sagittal reconstructions showed only right side C0- C1 assimilation. Figure 13: Osteogenesis by bone lengtheninig: Application of the maxillary distractor and the mandibular distractor after performing the Le Fort I osteotomy (white arrow) and the horizontal osteotomy of the mandibular ramus (black arrow). Figure 14: Intraoperative view of the maxillary distractor. Figure 15: 11-year old girl with right hemifacial microsomia. Frontal picture shows facial asymmetry and upward cant of the right labial commissure. Note the obliquity of occlusal plane. Page 15 of 38

Figure 16: Osteogenesis by bone lengtheninig: Same patient, ortopantomograms during double maxillo-mandibular elongation by an orthodontic distractor. Figure 17: Same patient, post osteogenesis by double maxillo-mandibular elongation. Frontal picture shows a perfect correction of the occlusal plane. Figure 18: Bilateral external ear aplasia in a patient with mandibulofacial dysostosis ( Treacher Collins syndrome), (a) ear epithesis retained by endosseous implants. Figure 19: Ear epithesis. same patient in figure 23. Transcutaneous abutments of two temporal fixatures. Figure 20: left epithesis and BAHA (Bone Anchored Hearing Aid) retained on another implant. Images for this section: Page 16 of 38

Fig. 1: 16 year-old girl with left side hemifacial microsomia. Lateral cephalometric radiograph shows asymmetrical mandibular angles (arrows). Page 17 of 38

Fig. 2: Same patient.the Orthopantomogram shows the hypoplasia of the left ascending ramus of the mandible and the coronoid process. Page 18 of 38

Fig. 3: Same Patient. 3D volume rendering CT: Inferior lateral view of the left pathological side with the hypoplasia of the ascending ramus and malformation of the coronoid process. Page 19 of 38

Fig. 4: Mandibulofacial dysostosis ( Treacher Collins syndrome). Lateral cephalometric radiograph shows hypoplasia of the malar bone, mandible and the mastoid. Note the metallic structures for the retention of ear epithesis. Page 20 of 38

Fig. 5: Mandibulofacial dysostosis ( Treacher Collins syndrome). lateral view 3D volume rendering CT demonstrates hypoplasia of the malar bone and mandible (ascending ramus and condyle). Note also, the orbito-zygomatic malformation. Page 21 of 38

Fig. 6: Pierre Robin syndrome. 3DCT VRT, Lateral view showing a retrognathism with mandibular hypoplasia. Note the global hypoplasia of the mandible without dysplasia. Page 22 of 38

Fig. 7: Temporal bone abnormality: Note abnormality of right malar bone with hypoplasia of zygomatic arch as well as dysplasia of right mastoid bone. Note also, right side muscular atrophy of masseter and pterygoid muscles. Page 23 of 38

Fig. 8: External and middle ear abnormalities: 16 year old girl with right hemifacial microsomia. Axial CT depicts dysplasia of right tempanic cavity with complete absence of right side middle ear ossicles associated with hypoplasia of mastoid air cells. Note also external ear anomaly. Page 24 of 38

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Fig. 9: Inner ear abnormalities: Right side internal auditory canal hypoplasia in comparison with the normal left side in this patient with right hemifacial microsomia. Fig. 10: Associated abnormalities detected by axial CT depicted a Lipoma of corpus callosum in a 15 years old girl with Goldenhaar syndrome. Page 26 of 38

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Fig. 11: 29 year old boy with hemifacial microsomia and Klippel-Feil syndrome. 3D volume rendering images showe bilateral assimilation between occipital condyles and the posterior arc of the atlas. So, 3D volume rendering techniques could lead to overestimations or underestimations of bone diseases depending on the selected Hounsfield Units threshold used. Fig. 12: Same patient of fig.17: thin section coronal and sagittal reconstructions showed only right side C0-C1 assimilation. Page 28 of 38

Fig. 13: Application of the maxillary distractor and the mandibular distractor after performing the Le Fort I osteotomy (white arrow) and the horizontal osteotomy of the mandibular ramus (black arrow). Page 29 of 38

Fig. 14: Intraoperative view of the maxillary distractor. Page 30 of 38

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Fig. 15: 11-year old girl with right hemifacial microsomia. Frontal picture shows facial asymmetry and upward cant of the right labial commissure. Note the obliquity of occlusal plane. Fig. 16: Osteogenesis by bone lengtheninig: Same patient, ortopantomograms during double maxillo-mandibular elongation by an orthodontic distractor. Page 32 of 38

Fig. 17: Same patient, post osteogenesis by double maxillo-mandibular elongation. Frontal picture shows a perfect correction of the occlusal plane. Page 33 of 38

Fig. 18: Bilateral external ear aplasia in a patient with mandibulofacial dysostosis ( Treacher Collins syndrome), ear epithesis retained by endosseous implants. Page 34 of 38

Fig. 19: Ear epithesis. same patient in figure 23. Transcutaneous abutments of two temporal fixatures. Fig. 20: left epithesis and BAHA (Bone Anchored Hearing Aid) retained on another implant. Page 35 of 38

Conclusion complex first and second branchial arch syndromes are best understood using a multimodality imaging approach in order to increase the diagnostic efficiency. Extended knowledge of the embryology and anatomy of each branchial arch derivatives is mandatory in establishing the diagnosis of facial and branchial arch syndromes. Pantomograms, cephalometric radiographs, 2D and 3D CT should be used together for morphological mapping for surgical treatment planning. For grading different BAS, axial CT is essential for providing the detailed analysis of inner, middle and external ear structures as well as the skull base anomalies. 3D CT becomes of prime importance for pre surgical planning 3D measurement. Multimodality imaging approach is also essential to depict various associated brain and muscle anomalies and for the follow-up of postoperative patients. Personal Information Authors: 1 2 2 1 2 1 T. Laswad, L. Alamo, E. Sengen, D. Fournier, B. Jacques, F., J. Moreau ; 2. Gudinchet Page 36 of 38

1 Sion/CH, 2 Lausanne/CH References References 1. Moore K (1988) The Developing Human. Clinically oriented embryology. Toronto: W.B. Saunders Company, Philadelphia, London, 2. Carvalho GJ, Song CS, Vargervik K, Lalwani AK (1999) Auditory and facial nerve dysfunction in patients with hemifacial microsomia. Arch Otolaryngol Head Neck Surg 125:209-212 3. Cobourne MT (2000) Construction for the modern head: current concepts in craniofacial development. J Orthod 27:307-314 4. Charrier JB, Bennaceur S, Couly G (2001) [Hemifacial microsomia. Embryological and clinical approach]. Ann Chir Plast Esthet 46:385-399 5. Rahbar R, Robson CD, Mulliken JB, Schwartz L, Dicanzio J, Kenna MA, McGill TJ, Healy GB (2001) Craniofacial, temporal bone, and audiologic abnormalities in the spectrum of hemifacial microsomia. Arch Otolaryngol Head Neck Surg 127:265-271 6. Tessier P (1976) Anatomical classification of facial, cranio-facial and latero-facial clefts. J. Maxillofac. Surg 4:69 7. Vento AR, LaBrie RA, Mulliken JB (1991) The O.M.E.N.S. classification of hemifacial microsomia. Cleft Palate Craniofac J 28:68-76; discussion 77 8. Ilizarov GA (1988) The principles of the Ilizarov method. Bull Hosp Jt Dis Orthop Inst 48:1-11 9. Scolozzi P, Herzog G, Jaques B (2006) Simultaneous maxillo-mandibular distraction osteogenesis in hemifacial microsomia: a new technique using two distractors. Plast Reconstr Surg 117:1530-1541; discussion 1542 Page 37 of 38

10. Ortiz Monasterio F, Molina F, Andrade L, Rodriguez C, Sainz Arregui J (1997) Simultaneous mandibular and maxillary distraction in hemifacial microsomia in adults: avoiding occlusal disasters. Plast Reconstr Surg 100:852-861 Page 38 of 38