Faculty Bibliography

BACKGROUND: It is essential to critically assess bone deposition in midface distraction. The aim of this study was to characterize the quality and volume of bone deposition at specific osteotomy sites following midface distraction. METHODS: At approximately 6 months after distraction, computed tomographic scans with three-dimensional reconstruction were obtained on 10 craniosynostosis syndromal patients who had undergone LeFort III osteotomy and midface distraction. Patient age ranged from 37 to 109 months (mean, 63.7 months) and the distractions ranged from 7 to 15 mm. Both the reconstructed scans and axial cuts were independently evaluated by four blinded observers (two plastic surgeons, an orthodontist, and a radiologist) and graded for bone deposition in predetermined anatomical sites correlated to the osteotomy. RESULTS: The authors found that variable bony bridging occurred at all sites along the osteotomy, but bone deposition was most reliably seen at the pterygomaxillary buttress and nasofrontal junction. In addition, the medial orbital walls tended to show greater consistency in bone deposition than the lateral orbital walls, and deposition at the zygomatic arches was shown to be least likely to occur. The technique of evaluation and the clinically significant findings are discussed. CONCLUSIONS: Bony deposition occurs more reliably in the medial facial skeleton following LeFort III osteotomy, and osteotomy through the zygomatic body was more likely to result in deposition than one through the arch

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

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

We present a 26-year-old patient with juvenile-onset arthritis, Alagille's syndrome, micrognathia, and progressive sleep apnea. Despite the presence of significant temporomandibular joint pathology, mandibular distraction was indicated to correct life-threatening sleep apnea. Before distraction, the patient had only 10 mm of maximal interincisal opening and bilateral temporomandibular joint symptomatology. After distraction, the patient's sleep apnea resolved. There was slight improvement in her maximal incisal opening (12 mm) with neither exacerbation nor improvement of her temporomandibular joint symptomatology

The purpose of this retrospective study was to evaluate the extent to which an early Le Fort III osteotomy affects the position and eruption of the permanent maxillary first and second molars. To test the null hypothesis that there are no changes in eruption patterns, 31 patients diagnosed with craniosynostoses (13 with Crouzon's syndrome, nine with Apert's syndrome, eight with Pfeiffer's syndrome, and one with Carpenter's syndrome) with a mean age at the time of surgery of 5.3 +/- 1.3 years were studied. All patients underwent a Le Fort III osteotomy performed by a single surgeon to correct the anatomical deformity for functional and psychosocial reasons. Eighteen patients with craniosynostoses who had not been operated on (11 with Crouzon's syndrome, four with Apert's syndrome, and three with Pfeiffer's syndrome) served as controls; they had a mean age of 21.2 +/- 9.5 years. First and second molar positions and eruption patterns were assessed separately on panoramic radiographs by three observers. For the patients who underwent surgery, long-term evaluation showed that although 79 percent of all first molars erupted compared with 100 percent for the control group (p < 0.001), only 18 percent of all second permanent molars erupted compared with 89 percent for the control group (p < 0.0001). The authors conclude that in a significant minority of cases, early Le Fort III osteotomy affects first molar eruption, whereas the probability of second molar eruption is significantly decreased in the majority of cases. Therefore, Le Fort III osteotomy sites should be positioned distal to the second molar tooth buds. If this is not possible, patients, parents, and dental professionals should be made aware of these early postosteotomy sequelae so that later treatment planning can be enhanced.

OBJECTIVES: To examine the long-term effect of nasoalveolar molding and gingivoperiosteoplasty (modified Millard type) on midface growth at prepuberty. PROCEDURES: In this retrospective study, 20 consecutive patients with a history of complete unilateral cleft lip and palate were evaluated. Ten patients had nasoalveolar molding and gingivoperiosteoplasty performed at lip closure; 10 control patients had nasoalveolar molding but no gingivoperiosteoplasty because of late start in treatment or poor compliance. A single surgeon (C.B.C.) performed all surgical procedures. Standardized lateral cephalometric radiographs were evaluated at two time periods: T1 at pre-bone-grafting age and T2 at prepuberty age. Superimposition and cephalometric analysis were undertaken to investigate the two groups. Two cephalometric reference planes, sella-nasion and basion-nasion, were used to assess the vertical and sagittal relations of the midface (ANS-PNS). The reference landmarks were procrustes fitted. The mean location and variance of ANS and PNS landmarks were computed. All results were analyzed by permutation test. RESULTS: No significant difference in mean location or variance of ANS-PNS in both vertical and sagittal planes at both T1 and T2 periods were found between the two groups (p > .05). CONCLUSIONS: The results suggested that midface growth in sagittal or vertical planes (up to the age of 9 to 13 years) were not affected by presurgical alveolar molding and gingivoperiosteoplasty (Millard type).

The principle objective of presurgical nasoalveolar molding (NAM) is to reduce the severity of the initial cleft deformity. This enables the surgeon and the patient to enjoy the benefits associated with a repair of a cleft deformity that is of minimal severity. Retraction of the premaxilla, presurgical elongation of the columella, correction of the nasal cartilage deformity, alignment of the cleft alveolar segments, increase in the surface area of the nasal mucosal lining, up-righting of the columella, and achieving close approximation of the cleft lip segments at rest result from gentle application of forces through the NAM appliance. Preservation of these presurgical changes is achieved through the coordinated and modified surgical technique of the primary cleft repair