Faculty Bibliography

This article presents a method of cephalometric tracing and analysis using the basilar view cephalogram and discusses its role in diagnosis and treatment planning. Landmarks and structures found in each of three separate basilar planes are defined and instructions for tracings are presented. The analysis is applied to the study of orbital hypertelorism, craniofacial synostosis, and hemicraniofacial microsomia. The multiplane tracing technique is demonstrated to provide a three-dimensional concept of deformities in the craniofacial skeleton. A method to determine an anteroposterior midline construct from structures in the cranial base is described. As is practiced with the lateral cephalogram, presurgical tracings of the basilar film may be manipulated to simulate the skeletal changes anticipated in surgery

The method of mean tensor analysis was used to study the cranial base in six craniofacial anomalies: Crouzon's disease, Apert's syndrome, Pfeiffer's syndrome, craniofacial microsomia (CFM), Treacher Collins (TC) syndrome, and frontonasal dysplasia (FND). The form was represented by five landmarks: the nasion (N), basion (Ba), sella (S), frontomaxillonasal suture (FMN), and sphenoethmoidal registration point (SE), and the deformities were computed as mean deformations from age- and sex-matched normal mean forms. The cranial base in CFM is normal in shape. The other five syndromes manifest four distinct patterns of shape variation. Only in TC and Pfeiffer's syndrome is the cranial-base angle distinctive. In Apert's and Crouzon's syndromes, point SE is displaced anteriorly upon a cranial base, small in size but otherwise normal in shape. In TC syndrome and FND, point SE is displaced posteriorly toward the sella

A prospective clinical and cephalometric study was conducted on 12 patients under the age of 12 years undergoing Le Fort III advancement with the following findings: 1. There was a remarkable degree of postoperative skeletal stability of the midfacial segment. 2. Disharmony in jaw relationship (anterior crossbite) observed during the period of longitudinal postoperative study could be attributed to expected mandibular development. 3. In some patients, growth and development of the maxilla in a forward and downward direction were documented after Le Fort III advancement. The authors recommend that a Le Fort III advancement can be safely performed at approximately age 4 without a deleterious effect on midfacial development in the patient with craniofacial dysostosis

A prospective review is presented of 50 patients with one of the craniofacial synostosis syndromes who underwent early interventive craniofacial surgical correction (average age 7.6 months at time of surgery). The study has demonstrated the efficacy and safety of the techniques when employed in the infant. Satisfactory cranio-orbital form was achieved in the majority of the patients, although 10 patients required secondary surgery because of sutural refusion or the development of turricephaly or calvarial contour irregularities. Despite earlier hopes, this surgery did not result in the development of satisfactory occlusal relationships and midfacial form in the craniofacial dysostosis group (Crouzon's, Apert's, etc.). Based on this clinical experience, a surgical treatment plan is presented for the newborn with craniofacial synostosis

A three-dimensional, multiplane cephalometric analysis is presented. This analysis permits visualization of skeletal midlines at selected depths of the craniofacial complex. When the midlines and associated anatomic structures are studied sequentially, the individual midlines may be combined conceptually into a warped midsagittal 'plane.' This localizes craniofacial asymmetry in the posteroanterior and basilar views. The study of structures in various coronal and transverse planes makes it possible to measure and record the three-dimensional relationships of anatomic structures to one another. A case of hemicraniofacial microsomia in which this analysis was used is presented

Various attempts to describe the skeletal characteristics of unilateral craniofacial microsomia have been made with the use of cephalometric and panoramic roentgenograms. Previous studies have been only descriptive in nature. To date, a detailed (quantitative) cephalometric analysis of the mandibular deformity has not been reported. The purpose of this study was to describe the skeletal jaw deformity by means of cephalometric landmarks in the lateral view. The patient population consisted of sixteen boys and eight girls who ranged in age from 6 to 16 years. They were compared to the University of Michigan normal control population for the following measures: gonial angle, mandibular plane angle, overall oblique length of the mandible, ramal height, and body length. The affected side showed a larger gonial angle and mandibular plane angle. The oblique length of the mandible (Cd-Gn) was decreased on both sides, as were ramal height and body length. Paradoxically, body length appeared shorter on the unaffected side than on the affected side. This paradoxical observation could be attributed to a shift of the mandible in relation to the midsagittal plane of the cranial base, the film cassette, and the path of the x-ray beam. Observation of the mandible in the basilar cephalogram explained the geometry of the projection error found in the lateral view. Similar projection errors exist for patients with other types of craniofacial asymmetry. It is suggested that two radiographic views, orthogonal to each other, should be used to define the x, y, and z planes for studies of craniofacial abnormality