Faculty Bibliography

The ability to avoid a subsequent bone graft makes the use of gingivoperiosteoplasty (GPP) at the time of cleft lip repair an attractive technique. The use of GPP, in combination with presurgical orthodontics, has been shown to result in successful bony union in the majority of patients. However, secondary bone grafting is still necessary in 30% to 40% of patients due to persistent alveolar bony defects. The elucidation of methods to improve the success rates of these procedures has been hampered by the lack of reproducible animal models. The purpose of this study was, therefore, to develop a rodent model of GPP that would facilitate the investigation of methods to improve osteogenesis in alveolar defects. We report a surgically produced rat model (9 x 5 x 3-mm alveolar defect) that is reproducible, inexpensive (relative to large-animal models), and simple technically. In addition, healing in this model occurs in a predictable manner during a 12-week period, thus enabling analysis of methods designed to accelerate or facilitate osseous regeneration

Presurgical infant orthopedics has been employed since the 1950s as an adjunctive neonatal therapy for the correction of cleft lip and palate. In this paper, we present a paradigm shift from the traditional methods of presurgical infant orthopedics. Some of the problems that the traditional approach failed to address include the deformity of the nasal cartilages in unilateral as well as bilateral clefts of the lip and palate and the deficiency of columella tissue in infants with bilateral clefts. The nasoalveolar molding (NAM) technique we describe uses acrylic nasal stents attached to the vestibular shield of an oral molding plate to mold the nasal alar cartilages into normal form and position during the neonatal period. This technique takes advantage of the malleability of immature cartilage and its ability to maintain a permanent correction of its form. In addition, we demonstrate the ability to nonsurgically construct the columella through the application of tissue expansion principles. This construction is performed by gradual elongation of the nasal stents and the application of tissue-expanding elastic forces that are applied to the prolabium. Use of the NAM technique has eliminated surgical columella reconstruction and the resultant scar tissue from the standard of care in this cleft palate center

OBJECTIVE: This objective of this study was to determine the effect of presurgical nasoalveolar molding on long-term nasal shape in complete unilateral clefts. DESIGN: The study was retrospective, and the subjects were chosen at random. Nasal casts of the subjects were scanned in three dimensions. Each nose was best fit to its mirror image, and a numerical asymmetry score was determined. SETTING: All patients were treated at the Institute of Reconstructive Plastic Surgery, NYU Medical Center, New York, New York. PATIENTS: The study subjects (n = 10) were selected from a group that had undergone presurgical nasal molding in conjunction with alveolar molding. The control subjects (n = 10) were selected from a group that had undergone presurgical alveolar molding alone. INTERVENTIONS: All subjects underwent presurgical orthopedic treatment until the age of approximately 4 months at which time the primary surgery was performed. MAIN OUTCOME MEASURE: The nasal shape following nasal molding should be more symmetrical than if molding had not been done. RESULTS: The mean asymmetry index for the nasoalveolar molding group was 0.74, and the control group was 1.21. This difference was statistically significant (p < .05). CONCLUSIONS: Presurgical nasoalveolar molding significantly increases the symmetry of the nose. The increase in symmetry is maintained long term into early childhood. The limitations of this study include (1) asymmetry alone is not an adequate shape result in most situations, (2) the children evaluated in this study were not fully grown, and (3) the control group was not age matched

Distraction osteogenesis is an effective technique for reconstruction of the congenitally deficient mandible. However, the age at which it is best performed remains under discussion. Distraction performed at an early age, while possibly allowing the face to develop with a more normal functional matrix, may entail a higher rate of complications. Additionally, it is possible that subsequent asymmetric growth of the mandible may necessitate serial distraction. To address this issue, the clinical records and cephalometric radiographs of all patients less than 48 months of age undergoing mandibular distraction at New York University Medical Center between August of 1989 and August of 1997 were examined. There was a total of 14 patients ranging in age from 19 months to 43 months. Nine patients had a diagnosis of unilateral craniofacial microsomia, three had Treacher Collins syndrome, one had Nager syndrome, and one had bilateral developmental micrognathia. The average amount of distraction was 27 mm (range, 23 to 39 mm) in unilateral cases and 24 mm in bilateral cases (range, 15 to 31 mm). The period of clinical follow-up averaged 32.6 months (range, 12 to 92 months). All patients showed significant improvement in craniofacial appearance, and in four patients, long-term tracheostomy tubes were removed. There were two major complications. In one patient with craniofacial microsomia, there was a relapse in the early postretention phase related to the presence of a dentigerous cyst. This required removal of the cyst and repeat distraction. In the patient with Nager syndrome, a coronoid ankylosis developed requiring surgical release. There were no other major complications. The scars required revision in only two of the patients. Cephalometric analysis of the patients in the study revealed a differential in the rate of growth between the affected and the unaffected side in all cases of craniofacial microsomia. The affected side always grew at a slower rate than the contralateral side after the distraction process was complete. This led to a progressive asymmetry of the rami, clinically expressed by some degree of facial asymmetry and an occlusal cant. For this reason, secondary distraction was required in one patient and is planned in a second. Initial overcorrection of the patient would seem to minimize the likelihood that secondary distraction will be necessary. Distraction osteogenesis for reconstruction of the mandible in this subset of young patients was a safe and effective technique for improving the craniofacial skeletal form and appearance, with minimal associated morbidity. Longer follow-up is necessary to assess the full impact of growth in these cases

Mandibular distraction has been performed at the authors' institution for the past 10 years on a variety of craniofacial anomalies. This article reviews the experience with distraction and outlines the authors' treatment algorithms based on patient age and pathology. The roles of distraction versus conventional orthognathic surgery are reviewed. The need for preoperative surgical planning and postoperative orthodontic therapy is emphasized

As in traditional combined surgical and orthodontic procedures, the orthodontist has a role in the planning and orthodontic support of patients undergoing distraction osteogenesis. This role includes predistraction assessment of the craniofacial skeleton and occlusal function in addition to planning both the predistraction and postdistraction orthodontic care. Based on careful clinical evaluation, dental study models, photographic analysis, cephalometric evaluation, and evaluation of three-dimensional computed tomographic scans, the orthodontist, in collaboration with the surgeon, plans distraction device placement and the predicted vectors of distraction. Both surgeon and orthodontist closely monitor the patient during the active distraction phase, using intermaxillary elastic traction, sometimes combined with guide planes, bite plates, and stabilization arches, to mold the newly formed bone (regenerate) while optimizing the developing occlusion. Postdistraction change caused by relapse is minimal. Growth after mandibular distraction is variable and appears to be dependent on the genetic program of the native bone and the surrounding soft tissue matrix. A significant advantage of distraction osteogenesis is the gradual lengthening of the soft tissues and surrounding functional spaces. Distraction osteogenesis can be applied at an earlier age than traditional orthognathic surgery because the technique is relatively simple and bone grafts are not required for augmentation of the hypoplastic craniofacial skeleton. In this new technique, the surgeon and the orthodontist have become collaborators in a process that gradually alters the magnitude and direction of craniofacial growth

Obstructive sleep apnea in the neonatal period may originate from a hypoplastic mandibular framework causing retroposition of the base of the tongue and an inadequate hypopharyngeal space. A tracheotomy in childhood is an effective treatment for obstructive sleep apnea, but it is associated with increased morbidity, management problems, and difficulties in social interaction. Tracheostomy-dependent pediatric patients who underwent mandibular distraction were reviewed to determine the effectiveness of this technique in achieving decannulation. A clinical review was completed to determine the status of the tracheostomy after external, unidirectional distraction in tracheostomy-dependent patients. Expansion of the mandibular framework was analyzed using traditional bony landmarks on predistraction and postdistraction lateral cephalograms. The area of the lower face was analyzed, and changes in the position of the hyoid bone were determined. Four patients with tracheostomies underwent an average of 21.3 mm and 20.8 mm of distraction on the left and right hemimandibles, respectively. The average age at the time of distraction was 2.7 years (range, 2.2 to 3.2 years). All patients underwent successful decannulation at an average of 3.8 months (range, 1.5 to 5.5 months) after completion of distraction. The area of the lower face increased 26.9 percent (range, 12.2 to 53.5 percent) after distraction, and the hyoid bone advanced an average of 14.5 mm (range, 8 to 25 mm). Bilateral mandibular distraction is an effective method of expanding the mandibular framework and concomitantly advancing the base of the tongue. The technique provides a tool for early intervention and decannulation in pediatric patients with indwelling tracheostomies secondary to mandibular deficiencies

This article reports our clinical experience since 1994 with rigid-motion tracking of bone fragments during craniofacial surgical procedures, using a virtual reality approach. Three noncollinear infrared diodes are fixed to the skull base. A pointer is used to register anatomic features on the patient to those on the computerized tomography-based model of the patient within a computer work station. Three diodes are then attached to each fragment just before the osteotomy is completed. Rigid motions of the fragment are thus tracked and reported to the surgeon by using virtual reality techniques. Errors in fragment positioning are reported both graphically and numerically with respect to a precomputed optimum fragment position. This guidance system allows multisegment midface osteotomies to be performed more precisely. The main problems encountered so far have been devascularization-infection and difficulties in maintaining correct position during application of rigid fixation. Devascularization-infection problems have been addressed by minimizing surgical exposure of the bone. Soft-fixation plates and temporary Kirschner wire fixation have helped with intermediate positioning, but an intraoperative mechanical positioning device would be useful in the future