第1, 第2鰓弓症候群の1例

抄録

The first and second branchial arch syndrome is a rare anomaly characterized by hypoplasia of mandibular ramus, temporomandibular joint and ear. The hypoplasia involving both skeletal and soft tissues results in severe facial asymmetry increasing progressively. The present paper reports a case of this anomaly.
A 28 year-old female was admitted. Clinical examination showed hypoplasia of the middle and lower thirds of the left side of the face, canted mouth and malformed ear. Chin was significantly deviated to the left and retropositioned. Radiographic and CT examinations revealed hypoplasia of left mandibular ramus and angle, coronoid process, temporomandibular joint, muscles of mastication and parotid salivary gland. Intraoral evaluation showed canted occlusal plane with rigid interdigitation of occlusion. Both anteroposterior and lateral cephalometric analyses disclosed three-dimensional hypoplasia and deviation of the upper and lower jaws: that is, upward and posteromedial displacement of the affected malar bone and maxilla, upward and medial displacement of the affected temporomandibular joint, mandibular ramus and angle, deviation to the affected side and retroposition of the chin and the dental midline, canted occlusal plane and so forth.
The first treatment consisted of Le Fort I osteotomy, sagittal splitting osteotomy and genioplasty. This corrected the frontal and sagittal asymmetry, but the transverse asymmetry remained because the middle and lower thirds of the unaffected side of the face protruded farther and those of the affected side was more hollowed by the first reatment. At the second treatment iliac bone onlay graft was done on the affected mandibular ramus and angle, and masseter muscle myotomy and posterior and inferior border resection ostectomy of mandible were accomplished on the unaffected side. The two-stage surgery resulted in alignment of the occlusal plane with a more symmetrical face.