Faculty Bibliography

BACKGROUND: Mandibular distraction has evolved from the use of external to the use of intraoral and semiburied devices. The authors highlight the evolution of the semiburied technique. The authors evaluate advantages and limitations, and report perioperative events for external and semiburied techniques to establish the indications for selection of the different devices. METHODS: A retrospective review was conducted of patients undergoing mandibular distraction at the New York University Langone Medical Center from the authors' introduction of mandibular distraction in May of 1989 to June 30, 2009. Perioperative events were stratified into three groups: minor incidents, moderate incidents, and major incidents. RESULTS: A total of 211 mandibular distraction procedures were performed: 129 external procedures on native bone, 37 external procedures on grafted bone, and 45 semiburied procedures on native bone. Minor incidents were more common with the semiburied device (62 percent) compared with external devices on native (26 percent) and grafted (38 percent) bone. There were fewer moderate incidents with the semiburied device (18 percent) than with the external device on native (22 percent) and grafted (30 percent) bone. In contrast to the external technique, no major incidents were seen with semiburied distraction. CONCLUSIONS: The semiburied device reduces scarring and has the mechanical advantages of being applied directly to the bone, less vulnerable to dislodgment, and more favorable for a vertical vector. However, its use requires more bone stock and it has the disadvantage of requiring a second operation for removal. Semiburied distraction is safe, reliable, and indicated for lengthening of the hypoplastic mandible where there is adequate bone stock for its attachment

BACKGROUND: Patients with Apert, Crouzon, and Pfeiffer syndromes who have severe midfacial hypoplasia are treated by Le Fort III midface advancement. The purpose of this study was to examine long-term (10-year) midface skeletal stability and growth following Le Fort III midface advancement in growing children. METHODS: A review of 192 patients with syndromic craniosynostosis treated by classic (nondistracted) Le Fort III advancement osteotomy between 1973 and 1998 was performed. Twenty-five patients met the inclusion criteria (age at surgery < 11 years and availability of cephalograms of diagnostic quality before treatment, after surgery, and at 1-, 5-, and 10-year follow-up). The mean age at the time of surgery was 5.8 years and the diagnosis was either Crouzon (n = 10), Apert (n = 9), or Pfeiffer (n = 6) syndrome. RESULTS: After surgery, point A advanced sagittally 10.72 mm and moved downward 3.77 mm. At 1 year, point A moved forward 0.10 mm and downward 0.47 mm. At 5 years, point A moved back 0.18 mm, whereas at 10 years it advanced 0.12 mm. During the same periods, however, pogonion came forward 5.72 mm and 7.32 mm, respectively. CONCLUSIONS: Le Fort III midface advancement in growing children with syndromic craniosynostosis is stable after the first year postoperatively. There is minimal horizontal growth of the midface between postoperative years 5 and 10, although the mandible continues to grow. Due to the differential growth rate of the midface and mandible, the facial profile becomes concave, thereby necessitating secondary midface surgery at the completion of skeletal growth

BACKGROUND:: The purpose of this study was to compare clinical outcomes and 1-year postsurgical stability with three different techniques of Le Fort III midface advancement. METHODS:: The records of 212 syndromic craniosynostosis patients were reviewed from the period 1973 to 2006. A total of 60 patients satisfied the inclusion criteria, and the mean age of the sample at surgery was 6.2 years. In group I (1977 to 1987), fixation was performed by interosseous wiring and intermaxillary fixation; in group II (1987 to 1996), fixation was achieved by only rigid plate fixation; and in group III (2000 to 2005), the patients underwent midface distraction with the rigid external distraction device. Cephalometric landmarks were identified and digitized at each of the time intervals (preoperatively, postoperatively, and 1 year postoperatively). RESULTS:: The mean advancement measured at point A in group I averaged 9.7 mm; in group II, it was 10.6 mm; and in group 3, it was 16.1 mm. There was no statistically significant difference in the amount of advancement between groups I and II. However, when groups I and II were compared with group III, there was a statistically significant difference (p < 0.05). No statistical significance was noted within and between all three groups at 1-year follow-up. CONCLUSIONS:: Significantly larger midface advancement was achieved with rigid external distraction (group III) compared with classic Le Fort III midface advancement with wire (group I) or plate (group III) fixation. At 1 year after surgery, the three groups showed relative stability of the advanced midface segment

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