John W. Polley

Management of severe maxillary deficiency in childhood and adolescence through distraction osteogenesis with an external adjustable, rigid distraction device

We present our technique for maxillary distraction osteogenesis in patients with severe maxillary hypoplasia. With the use of an external, adjustable, rigid distraction device, we can now treat patients with severe maxillary hypoplasia with a precise and controlled distraction process, obtaining predictable results. This technique has allowed us to treat patients in all age groups. In this report we review our indications for maxillary distraction and describe our technique using an external, adjustable, rigid midface distraction device.

Rigid External Distraction: Its Application in Cleft Maxillary Deformities

&NA; Patients with severe maxillary hypoplasia secondary to congenital facial clefting present numerous challenging problems for the reconstructive surgeon. Traditional surgical/orthodontic approaches for these patients often fall short of expectations, especially for achieving normal facial aesthetics and proportions. The purpose of this paper is to present our clinical experience and cephalometric results with the use of rigid external distraction for the treatment of patients with severe maxillary deficiency. Eighteen consecutive orofacial cleft patients with severe maxillary hypoplasia were treated with maxillary distraction osteogenesis. Criteria for patient selection included severe maxillary hypoplasia with negative overjet of 8 mm or greater, patients with normal mandibular morphology, and patients with full primary dentition or older. There were 10 unilateral cleft lip and palate patients, 6 bilateral cleft lip and palate patients, and 2 patients with severe congenital facial clefting. A maxillary splint was prepared for each patient, and all patients underwent a high Le Fort I maxillary osteotomy. All surgery was performed on either an outpatient or a 23‐hour admission basis. No patient required blood transfusions or intermaxillary fixation. Two types of mechanical distraction were utilized in this series. In group 1 (n = 14), the patients underwent rigid external distraction with an external distraction device. In group 2 (n = 4), patients underwent face mask distraction with elastics. There was no surgical morbidity in any of the patients. For the patients in the rigid external distraction group, the mean effective horizontal advancement of the maxilla was 11.7 mm. All of these patients had correction of their negative overjet. For patients in the face mask distraction group, the results were disappointing. The mean effective advancement of the maxilla in this group was only 5.2 mm. In all face mask distraction patients, the initial maxillary hypoplasia was undercorrected. Maxillary distraction osteogenesis with rigid external distraction permits full correction of the midfacial deficiency, including both the skeletal and soft‐tissue deficiencies. Rigid external distraction in patients with severe maxillary hypoplasia allows full correction of the deformity through treatment of the affected region only. It offers the distinct advantage of correcting these severe deformities through a minimal procedure. Rigid external distraction has dramatically improved our treatment results for patients with severe cleft maxillary hypoplasia. (Plast. Reconstr. Surg. 102: 1360, 1998).

Management of severe cleft maxillary deficiency with distraction osteogenesis: Procedure and results ☆ ☆☆

Distraction osteogenesis has become an important technique to treat craniofacial skeletal dysplasia. In this study, the technique of maxillary distraction with a rigid external distraction device is presented. Cephalometric results in the first 14 consecutive patients are analyzed. The study sample consisted of 14 patients with various cleft types and maxillary hypoplasia treated with the rigid external distraction technique. Analysis of the predistraction and postdistraction cephalometric radiographs revealed significant skeletal maxillary advancement. All patients had correction of the maxillary hypoplasia with positive skeletal convexity and dental overjet after maxillary distraction. The morbidity for the procedure was minimal. Surgical and orthodontic procedures are thoroughly described.

Monobloc craniomaxillofacial distraction osteogenesis in a newborn with severe craniofacial synostosis: A preliminary report

Severe craniofacial synostosis can be a devastating problem for a newborn infant. Reasons for early surgical intervention include cranial stenosis, hydrocephalus, inadequate globe and corneal protection, compromised airway patency, and feeding problems. In this preliminary report, we describe the management of severe craniofacial synostosis in a newborn infant by means of cranial and midfacial distraction osteogenesis.

Rapid orthodontic tooth movement into newly distracted bone after mandibular distraction osteogenesis in a canine model.

Orthodontic tooth movement through recently distracted fibrous bone tissue has not been investigated previously. We hypothesized that a tooth can be moved into the fibrous new bone created by the distraction process at a rapid rate. Four mature beagle dogs were used in this study. An edentulous space was created in 2 weeks by using a bone-borne intraoral distraction device on each side of the mandibular body between the third and fourth premolars. Calibrated elastic threads with 50 g of orthodontic force were applied to move the fourth premolar into the edentulous space for 5 weeks. On one side, the tooth was moved simultaneously with distraction; and on the opposite side, it was initiated immediately after the cessation of distraction. The fourth premolars were moved 1.2 mm per week. The results indicated that the best time to initiate tooth movement was immediately after the end of distraction. With this approach, most of the periodontal support was preserved after orthodontic tooth movement. In contrast, moderate to severe alveolar bone loss was noted in the fourth premolars moved simultaneously with distraction. This is one of the first experimental studies to demonstrate successful rapid orthodontic tooth movement into an edentulous space newly created by distraction osteogenesis. Clinical implications of these results may be applied to relieve severe dental crowding and to correct sagittal or transverse dental arch discrepancies.

Changes in Speech following Maxillary Distraction Osteogenesis

OBJECTIVE The purpose of this study was to describe changes in articulation and velopharyngeal function following maxillary distraction osteogenesis. DESIGN This is a descriptive, post hoc clinical report comparing the performance of patients before and after maxillary distraction. The independent variable was maxillary distraction while the dependent variables were resonance, articulation errors, and velopharyngeal function. SETTING The data were collected at a tertiary health care center in Chicago. PATIENTS The data from pre- and postoperative evaluations of 18 maxillary distraction patients were used. OUTCOME MEASURES The outcome measures were severity of hypernasality and hyponasality, velopharyngeal orifice size as estimated using the pressure-flow technique, and number and type of articulation errors. RESULTS At the long-term follow-up, 16.7% exhibited a significant increase in hypernasality. Seventy-five percent of patients with preoperative hyponasality experienced improved nasal resonance. Articulation improved in 67% of patients by the 1-year follow-up. CONCLUSIONS In a predominately cleft palate population, the risk for velopharyngeal insufficiency following maxillary distraction is similar to the risk observed in Le Fort I maxillary advancement. Patients being considered for maxillary distraction surgery should receive pre- and postoperative speech evaluations and be counseled about risks for changes in their speech.

Distraction osteogenesis: its application in severe mandibular deformities in hemifacial microsomia.

&NA; The reconstruction of severe mandibular deformities in patients with hemifacial microsomia (HFM) is difficult. The multiple requirements include temporomandibular joint construction, mandibular ramus and body reconstructions with autogenous bone grafts, and soft tissue facial augmentation. The sequencing of these reconstructions include staged procedures, generally performed at the time of skeletal maturity. Mandibular distraction osteogenesis has gained popularity as a technique for managing patients with mandibular hypoplasia. However, the use of distraction osteogenesis in HFM patients with severe grade III mandibular deformities has not been previously addressed. The purpose of this report is to present our early findings with the clinical application of mandibular distraction osteogenesis in HFM patients with grade III mandibular deformities. In selected patients, mandibular distraction osteogenesis can be beneficial by improving overall facial symmetry and balance. Mandibular distraction osteogenesis has unique advantages for these patients in that it can be performed early in childhood with minimal morbidity. Through the use of clinical examples, the application, patient selection, and advantages and disadvantages of mandibular distraction osteogenesis in HFM patients with grade III mandibular deformities are discussed.

Maxillary distraction for the management of cleft maxillary hypoplasia with a rigid external distraction system

Maxillary hypoplasia is a common finding in patients with repaired orofacial clefts. Management of this condition has been a challenge to the reconstructive team. The introduction of distraction osteogenesis to treat craniofacial skeletal dysplasias has opened alternative approaches to manage these severe conditions. In this article, the authors present their technique to distract the hypoplastic cleft maxilla using a rigid external distraction device. The clinical assessment, indications, orthodontic procedure, surgical technique, and distraction protocol are reviewed. A case report shows the use of the technique. This technique allows the reconstructive team to treat patients in all age groups with predictable and stable results.

Longitudinal analysis of mandibular asymmetry in hemifacial microsomia.

&NA; Reconstruction of the mandible is one of the key elements in the skeletal rehabilitation of patients with hemifacial microsomia. Unfortunately, knowledge about longterm mandibular skeletal growth in these patients is lacking. The purpose of this study was to analyze mandibular skeletal growth longitudinally in unoperated hemifacial microsomia patients from childhood to adolescence. The longitudinal records of 26 patients with unoperated unilateral hemifacial microsomia were utilized. The average age at initial records was 3.1 years, and the average age at final records was 16.7 years. Posteroanterior cephalometric radiographs were utilized to evaluate both horizontal and vertical mandibular asymmetry. Patients also were analyzed according to the grade and side of the mandibular deformity. A paired t test (p < 0.05) and a two‐way ANOVA were used to analyze the data. There were 5 patients with grade I, 14 with grade II, and 7 with grade III. The results indicated that the skeletal mandibular asymmetry in hemifacial microsomia is not progressive in nature and that growth of the affected side in these patients parallels that of the nonaffected side. The grade and the side of the mandibular deformity did not influence these findings. These results should be considered when treatment strategies are developed to reconstruct the asymmetrical mandible in hemifacial microsomia.

A longitudinal three-dimensional evaluation of the growth pattern in hemifacial microsomia treated by mandibular distraction osteogenesis : a preliminary report

This study analyzed in three dimensions the longitudinal growth pattern of young patients with hemifacial microsomia (HFM) before and after mandibular distraction osteogenesis (DO). Six individuals with HFM (five boys and one girl; age at distraction, 12.5 +/- 2.4 years) were treated with similar procedures (surgery, type and direction of distraction, no functional orthodontic treatment before and after DO). Two individuals who did not undergo DO until late in their growth were used to compare growth patterns. In addition, one individual besides the six previously chosen sample in whom no DO was performed was also used to compare longitudinal growth patterns. Lateral and posteroanterior (PA) cephalograms were utilized preoperatively, spanning a period of 9 years. Computerized three-dimensional models were constructed from the lateral and PA cephalograms using a vector intercept algorithm. In the comparison group, for a period of 8 years on the affected side, the ramus height, body length, and total mandibular length increased at an average rate of 1.3, 1.9, and 3.0 mm per year respectively. On the unaffected side, the ramus height increased by 2.1 mm per year, 1.9 mm in the body, and 2.9 mm per year in total mandibular length. On average, the gonial angle on the affected side was increased by 1 deg per year, yet decreased by 1 deg per year on the unaffected side. The proportions between the affected to the unaffected side were maintained. In the six individuals 18 months after DO, it was found that the ramus height was reduced by 1.0 mm, whereas the body was found to resume its growth with a faster rate on the distracted side, maintaining its proportion. Angular changes demonstrated closing of the gonial angle on both the unaffected (0.5 deg) and distracted (3.5 deg) sides. Observed in three dimensions were the following: (1) On average, unoperated patients with isolated HFM tend to maintain their asymmetrical facial proportions and do not worsen substantially with time. (2) Different treatment effects were seen on the ramus, body, and total length of the mandible: changes in body length > ramus height > total length. (3) Eighteen months after DO, the correction was stable but with some degree of settling back from the initial overcorrection (< 5%). (4) Eighteen months after DO the mandibular body was found to have greater growth than the ramus. (5) Evaluating changes in three dimensions provides an improved understanding of the growth pattern and distraction effects on the mandible and its structural components. (6) Additional studies on the effect of mandibular distraction on other conditions involving mandibular deformities are required. In addition, the effect of various distractor devices should also be evaluated. Three-dimensional evaluation is recommended for improved accuracy.