Faculty Bibliography

BACKGROUND: Precise control of the position of the midface through distraction with the rigid external distraction (RED) device has been a challenge. The present RED device with wire attachments to the intraoral dental splint and to the skeletal bone plates allows for flexibility in the vertical plane of the osteotomized Le Fort III segment. This tends to rotate the midface in a counterclockwise direction with inferior movement of the posterior nasal spine. OBJECTIVES: To report the development of a rigid distraction splint attachment to the RED device that permits precise control of the position of the midface during the latency period and through the activation and consolidation phases. METHODS: This paper describes the appliance design and the clinical application of a new device in controlling the position of the midface during distraction. Placement of the device and application of the desired force vectors are discussed. Patients treated by this modified device are illustrated to document the planned midface position after Le Fort III midface advancement. RESULTS: Examination of predistraction and postdistraction cephalograms of 2 patients treated with the new device showed advancement with minimum inferior displacement of the midface during all phases of the distraction process. CONCLUSIONS: The new device prevents undesired inferior movement of the posterior midface immediately after osteotomy and helps to stabilize the midface during the latency period. The device enables directional control of the distraction vectors, resulting in more predictable midface position at the end of treatment

Presurgical infant orthopedics has been employed since 1950 as an adjunctive neonatal therapy for the correction of cleft lip and palate. Most of these therapies did not address deformity of the nasal cartilage in unilateral and bilateral cleft lip and palate as well as the deficiency of the columella tissue in infants with bilateral cleft. The nasolaveolar molding (NAM) technique a new approach to presurgical infant orthopedics developed by Grayson reduces the severity of the initial cleft alveolar and nasal deformity. This enables the surgeon and the patient to enjoy the benefits associated with repair of a cleft deformity that is minimal in severity. This paper will discuss the appliance design, clinical management and biomechanical principles of nasolaveolar molding therapy. Long term studies on NAM therapy indicate better lip and nasal form, reduced oronasal fistula and labial deformities, 60 % reduction in the need for secondary alveolar bone grafting. No effect on growth of midface in sagittal and vertical plane has been recorded up to the age of 18 yrs. With proper training and clinical skills NAM has demonstrated tremendous benefit to the cleft patients as well as to the surgeon performing the repair

BACKGROUND: The purpose of this investigation was to determine the response of the osteotomized Le Fort III midface bony segment to variations in the location and direction, or vector, of force application on using the rigid external distraction device. METHODS: This retrospective study involved 18 consecutive syndromic craniosynostotic patients (average age, 5.7 years) who underwent Le Fort III midface advancement distraction. Various cephalometric and novel landmarks, located on the mobilized Le Fort III segment and on the components of the distraction device, were identified before activation and at mid-activation. The direction and magnitude of change for these points were recorded. RESULTS: Based on the observed change in the position of the midface during distraction, the sample was divided into the following groups. In group 1 (n = 5), the Le Fort III segment translated forward and no rotation was noted. In group 2 (n = 3), the Le Fort III segment rotated clockwise and showed downward displacement. In group 3 (n = 6), the Le Fort III segment showed forward displacement and rotated counterclockwise. In group 4 (n = 4), the Le Fort III segment translated forward and downward. CONCLUSIONS: Direction of movement and resultant change in position of the Le Fort III segment during distraction are directly related to the location and direction of force application. Translation forward, with minimal rotation, was achieved when the force was applied at a location 55 percent above the occlusal plane (between the occlusal plane and the nasion) and in a direction parallel to the maxillary occlusal plane

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: This article aims to assess the spectrum of unfavorable events or incidents encountered during mandibular distraction and to evaluate the difference in the incident rates among the following treatment groups: (1) native bone distraction using an external device, (2) native bone distraction using an internal device, and (3) grafted bone distraction using an external device. METHODS: This retrospective study examined the records of 141 patients treated by mandibular distraction over a 16-year period. Of the total 141 patients, 56 underwent unilateral mandibular distraction and 85 underwent bilateral mandibular distraction, contributing to a total of 226 sided distraction procedures. The number of procedures performed on native bone using external devices was 149, versus 41 internal devices. There were 36 distractions performed on grafted bone with external devices. Incidents were broadly classified into three groups based on a severity index. A minor incident was one that resolved satisfactorily with minimal or no invasive intervention. A moderate incident was one that resolved satisfactorily with moderate clinical intervention. A major incident was one that did not resolve or could not be resolved with surgical intervention, and compromised treatment outcome. RESULTS: The major incident rate was 5.31 percent (total of 226 distraction procedures). A higher rate of major incidents was observed when distracting grafted bone. The overall minor incident rate was 26.99 percent and the moderate incident rate was 20.35 percent. CONCLUSION: Mandibular distraction can be considered a safe and predictable procedure for lengthening/augmenting the mandible in patients with lower jaw deficiencies

BACKGROUND: The authors studied the effect of midface distraction on maxillary skeletal position and clinical appearance in patients with Crouzon, Pfeiffer, and Apert syndromes, and examined the stability of these changes at 1 year after distraction. METHODS: Fifteen consecutive patients (six male and nine female; average age, 5.9 years) underwent Le Fort III osteotomy with midface advancement using a rigid external distraction device. Six patients had Crouzon, five had Pfeiffer, and four had Apert syndrome. Midface advancement was initiated at the level of the occlusal splint and at the zygomatic/maxillary anchor screws. The device was activated 11 mm on average, at a rate of 1 mm per day. Twenty anatomical landmarks were identified and digitized at three time intervals, and displacement of each landmark was compared with its pretreatment position. RESULTS: By the time of device removal, point A had advanced sagittally along the x axis 15.85 mm and moved downward 1.06 mm along the y axis; the orbitale was moved sagittally along the x axis 12.72 mm and downward 1.99 mm along the y axis. Maximum mean advancement (17.16 mm) was observed at the upper incisal edge. Maxillary and mandibular skeletal discrepancy was significantly decreased, with the ANB angle changing from -5.87 to +13.17 degrees. At 1 year after distraction, point A had advanced an additional 0.81 mm, and the orbitale and upper incisal edge had moved posteriorly 0.07 mm and 1.34 mm, respectively. CONCLUSION: Significant midface advancement can be achieved and maintained with rigid external distraction of the Le Fort III osteotomy segment (up to 24 mm), with excellent stability of the advanced midfacial skeleton

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.

BACKGROUND: The purpose of this study was to evaluate long-term mandibular skeletal stability and growth following unilateral mandibular distraction in growing children. METHODS: This retrospective longitudinal study of 12 consecutive patients with unilateral craniofacial microsomia who underwent mandibular distraction had a range of 5 years of postdistraction follow-up; five patients were followed for 10 years. Records included clinical photographs, dental study models, lateral and posteroanterior cephalograms, and panoramic radiographs obtained before distraction, at the time of device removal, and 1, 5, and 10 years after distraction. The mean patient age at the time of distraction was 48 months. The device was activated an average of 21.7 mm at the rate of 1 mm per day. The mean latency period was 6.1 days, and the mean consolidation period was 60.6 days. Fifty-two parameters were examined at each of the five time intervals. RESULTS: On average, the ramal length (condylion to gonion) increased 13.04 mm in the distracted rami. At 1 year after distraction, this dimension decreased by 3.46 mm. At 5 and 10 years after distraction, the average condylion-gonion dimension increased by 3.83 and 4 mm, respectively, with an average growth rate of 0.87 mm per year; during the same period, the unaffected ramus grew 1.15 mm per year. CONCLUSIONS: The distraction technique does not eliminate the inherent growth potential of the affected mandibular side. Facial asymmetry is significantly improved after distraction, and despite mild relapse observed during the first year, surgical correction is stable in the later years of follow-up

OBJECTIVE: To examine lateral cephalometric radiographs of adult unoperated cleft lip and palate patients for the purpose of clarifying whether maxillary deficiencies observed in treated cleft patients result from intrinsic defects or surgical intervention early in life. MATERIALS AND METHODS: This retrospective study examined lateral cephalograms of 30 adult patients with nonsyndromic complete unilateral cleft lip and palate (CUCLP). The lateral cephalograms were traced and evaluated for size and position of the cranial base, maxilla, maxillary dentition, mandible, and mandibular dentition as well as for vertical relationships. Comparisons with 30 adult noncleft individuals were made. RESULTS: In unoperated adult cleft lip and palate patients, the cranial base angle was increased with the anterior cranial base reduced in length. The maxilla was found to be normal in size and somewhat prognathic in position. Both the maxillary and mandibular incisors were relatively upright. The mandible was smaller in size and posteriorly positioned. CONCLUSIONS: The potential for normal growth of the maxilla exists in patients with CUCLP. It is likely that disturbances of maxillary growth in surgically operated cleft patients are related primarily to the surgical intervention