Faculty Bibliography

BACKGROUND: Le Fort III distraction osteogenesis improves midface form and dental relationships in patients with syndromic craniosynostosis, but its effect on the upper airway is not well documented. METHODS: A retrospective review was conducted of patients with syndromic craniosynostosis undergoing Le Fort III distraction osteogenesis from 2000 to 2006 (n = 20). Changes in velar angle and nasopharyngeal, velopharyngeal, oropharyngeal, and hypopharyngeal spaces were measured cephalometrically. Three-dimensional airway casts were created from computed tomographic data to ascertain circumferential airspace changes. Patients with the preoperative diagnosis of severe obstructive sleep apnea or a tracheostomy were designated as having significant airway compromise. Cephalometric differences in the preoperative superior airspace were compared between patients with and without significant airway compromise. Improvement in the symptoms of obstructive sleep apnea was studied. RESULTS: Cephalometric analysis revealed an increase in the velar angle (121 degrees to 148 degrees; p < 0.001) and an increase in the nasopharyngeal (3.9 mm to 13.0 mm; p < 0.001) and velopharyngeal airspaces (2.0 mm to 5.9 mm; p < 0.01). Three-dimensional computed tomographic analysis confirmed these findings. Comparison between preoperative cephalograms of patients with (n = 10) and without significant airway compromise (n = 10) revealed smaller nasopharyngeal (2.2 mm versus 5.7 mm; p < 0.05) and velopharyngeal airspaces (0.9 mm versus 3.0 mm; p = 0.05). Nine of 10 patients with significant airway compromise experienced improvement in their symptoms of obstructive sleep apnea or had their tracheostomy removed. CONCLUSIONS: Le Fort III distraction osteogenesis significantly increases nasopharyngeal and velopharyngeal airspaces in patients with syndromic craniosynostosis. Midface distraction improves but does not resolve all causes of obstructive sleep apnea in this patient population

BACKGROUND: Bilateral cleft lip-cleft palate is associated with nasal deformities typified by a short columella. The authors compared nasal outcomes of cleft patients treated with banked fork flaps to those of patients who underwent nasoalveolar molding and primary retrograde nasal reconstruction. METHODS: A retrospective review of 26 consecutive patients with bilateral cleft lip-cleft palate was performed. Group 1 patients (n = 13) had a cleft lip repair and nasal correction with banked fork flaps. Group 2 patients (n = 13) had nonsurgical columellar elongation with nasoalveolar molding followed by cleft lip closure and primary retrograde nasal correction. Group 3 patients (n = 13) were age-matched controls. Columellar length was measured at presentation and at 3 years of age. The number of nasal operations was recorded to 9 years. The Kruskal-Wallis and Tukey-Kramer tests were used for statistical analysis. RESULTS: Initial columellar length was 0.49 +/- 0.37 mm in group 1 and 0.42 +/- 0.62 mm in group 2. Post-nasoalveolar molding columellar length was 4.5 +/- 0.76 mm in group 2. By 3 years of age, columellar length was 3.03 +/- 1.47 mm in group 1, 5.98 +/- 1.09 mm in group 2, and 6.35 +/- 0.99 mm in group 3. Group 2 columellar length was significantly greater (p < 0.001) than that of group 1 and not statistically different from that of group 3 (p > 0.05). All group 1 patients (13 of 13) needed secondary nasal surgery. No nasoalveolar molding patients (zero of 13, group 2) required secondary nasal surgery. CONCLUSION: Nonsurgical columellar elongation with nasoalveolar molding followed by primary retrograde nasal reconstruction restored columellar length to normal by 3 years and significantly reduced the need for secondary nasal surgery.

BACKGROUND: Unilateral craniofacial microsomia is characterized by soft-tissue and bony deficiencies. Mandibular distraction osteogenesis can be used to augment the hypoplastic skeleton and improve facial symmetry. The aim of this study was to determine how the vector of unilateral mandibular distraction affects treatment outcomes. METHODS: A retrospective chart and radiographic review was conducted of all patients treated with external mandibular distraction osteogenesis between October of 1990 and February of 2004 (n = 185). A subset of 42 patients underwent primary unilateral, uniplanar, external distraction, and 13 patients were found to have satisfied inclusion criteria and had adequate predistraction and postdistraction lateral and posteroanterior cephalograms. Cephalometric tracings were made and multiple points and planes were assessed before and after distraction. RESULTS: A strong correlation was noted between the vector of distraction and the movement of the mandible. A horizontal vector of distraction resulted in minimal increase in ramal length but a marked shift in the mandibular midline (r = 0.68, p < 0.05). In contrast, a vertical vector of distraction resulted in marked mandibular ramus lengthening but minimal mandibular midline shift (r = 0.73, p < 0.05). Mathematical formulas were derived to correlate the distraction vector and mandibular movements to improve preoperative planning. CONCLUSIONS: Successful distraction is dependent on accurate preoperative planning and prediction of outcomes. This study demonstrates a predictable relationship between the vector of unilateral distraction and the mandibular response

BACKGROUND: The application of distraction osteogenesis is an effective treatment for mandibular deficiencies. A priori, a horizontal vector of distraction was hypothesized to produce horizontal movement of the mandible and a vertical vector of distraction to produce primarily downward vertical elongation of the ramus. This study was designed to test this hypothesis. METHODS: A retrospective clinical and radiographic review was conducted of all patients who underwent bilateral, uniplanar distraction with an external device at the New York University Medical Center between October of 1990 and February of 2004 (n = 185). A subset of 15 patients was identified who satisfied inclusion criteria and had adequate predistraction and postdistraction lateral cephalograms. Cephalometric tracings were made and multiple landmarks were assessed before and after distraction. RESULTS: A strong correlation was noted between the vector of distraction and rotation of the symphyseal plane, movement of the mandibular symphysis, and change in interocclusal angle. A horizontal vector of distraction resulted in minimal counterclockwise rotation of the symphyseal plane, greater downward vertical translation of the mandibular symphysis, and minimal closure of an anterior open bite. In contrast, a vertical vector resulted in greater counterclockwise rotation of the symphyseal plane, greater horizontal projection of the mandibular symphysis, and greater closure of an anterior open bite. Mathematical formulas were derived to correlate the distraction vector and mandibular movements. CONCLUSIONS: Successful distraction is dependent on accurate prediction of outcomes. This study demonstrates that the vector of distraction predictably affects the mandibular response during bilateral distraction osteogenesis but contradicts the a priori hypothesis

BACKGROUND: Gingivoperiosteoplasty has been shown to eliminate the need for secondary alveolar bone grafting in 60 percent of patients. The purpose of this study was to compare radiographic alveolar anatomy following infant gingivoperiosteoplasty, secondary alveolar bone grafting, and secondary alveolar bone grafting in patients who had prior infant gingivoperiosteoplasty with inadequate bone formation. METHODS: Seventy-four consecutive nonsyndromic patients (complete bilateral cleft lip-cleft palate, n = 12; complete unilateral cleft lip-cleft palate, n = 46; complete unilateral cleft lip and alveolus, n = 14) treated at New York University Medical Center were available for evaluation. Eighty-two complete alveolar cleft sites were assigned to three groups: gingivoperiosteoplasty (n = 30), secondary alveolar bone grafting (n = 41), and secondary alveolar bone grafting following gingivoperiosteoplasty (n = 11). All gingivoperiosteoplasties were performed at the time of primary lip surgery, and secondary alveolar bone grafting (cancellous iliac crest at 7 to 12.5 years of age) was performed before eruption of the permanent canine. Radiographs were measured according to the modified method of Long. RESULTS: Seventy-three percent of gingivoperiosteoplasty cases did not require secondary alveolar bone grafting and none had fistulas. The rate of missing teeth in the total sample, adjacent to the cleft, was within normal limits for the population. Group 1 alone and groups 1 and 3 combined had superior alveolar anatomy compared with group 2 (p < 0.01). No significant differences existed between groups 1 and 3 (p > 0.05). Crest height was best in group 1 (p < 0.01), followed by group 3 and then group 2, with no difference between the latter two groups. CONCLUSION: Gingivoperiosteoplasty alone or combined with secondary alveolar bone grafting results in superior bone levels when compared with conventional secondary alveolar bone grafting alone

BACKGROUND: The purpose of this study was to investigate the relationship between soft-tissue and underlying skeletal structures before and after unilateral mandibular distraction osteogenesis. METHODS: The sample consisted of 11 patients (three girls and eight boys) with an average age of 4.6 years at the time of treatment. All patients had unilateral craniofacial microsomia (four right-sided and seven left-sided unilateral craniofacial microsomia) and all underwent unilateral mandibular distraction osteogenesis. Measurements were performed on frontal medical photographs and posteroanterior cephalograms at predistraction (time 1) and postdistraction (time 2) periods. Left and right ramus heights, skeletal midline deviation, and transverse occlusal plane were measured on the posteroanterior cephalograms and compared with the linear distances between the lip commissures and the orbital plane, the circumference of both sides of the faces, and the angulation of the oral commissure plane as recorded on the medical photographs, respectively. To reduce magnification error, ratios of affected to less affected sides of the mandibles and soft-tissue facial structures were selected and studied. RESULTS: A similar relationship was observed between soft-tissue and skeletal components. However, there was no 1:1 relationship between the changes in ramus height and improvement in parallelism of lip commissures to the orbital plane. CONCLUSIONS: A significant improvement in soft- and hard-tissue anatomy has been observed following unilateral distraction osteogenesis of the mandible. The relationship between the soft-tissue and skeletal correction was different for all patients because of the large range in severity of the craniofacial malformation. Greater skeletal deficiency requires more correction to achieve symmetry of both hard and soft tissue

The purpose of this study was to examine mandibular morphology and growth in patients with Crouzon, Pfeiffer, and Apert syndromes using posteroanterior cephalograms. Fifteen patients with Apert (n = 2), Crouzon (n = 11), and Pfeiffer (n = 2) (11 female, 4 male) syndrome were included in this study. All patients had serial posteroanterior cephalograms at 5, 10, and 15 years of age. The bicondylar width, bigonial width, bicondylar/bigonial ratio, and ramus to intercondylar plane angle for each patient were measured on the cephalograms and compared with age-match controls. An analysis of variance analysis was carried out to detect differences between patients and controls and sex differences between patients. In both male and female patients, there was a statistically significant reduction in bicondylar width compared with age-matched controls. Male patients also had a statistically significant increase in bigonial width compared with controls and female patients at 10 and 15 years. The resulting bicondylar/bigonial ratios were significantly reduced, and the ramus to intercondylar plane angles were significantly increased in both male and female patients compared with controls. Unlike previous reports of patients with syndromic synostosis, this study demonstrates that the mandible has significant morphologic and growth abnormalities, including constriction of bicondylar width with near normal bigonial width in female patients. These findings suggest a narrowing at the cranial base with resulting restriction of normal transverse mandibular growth at the condyle. The secondary nature of the mandibular finding is suggested by the near normal or increased transverse growth at the gonion in females and males, respectively. Consequently, the ramus appears torqued inward, forming a greater angle with the cranial base.