Management of the severe cleft and syndromic midface hypoplasia.

Distraction Osteogenesis (DO) has become a treatment alternative to treat severe craniofacial skeletal dysplasias. A rigid external distraction (RED) device has been successfully used to advance the maxilla as well as the maxillary, orbital and forehead complex (monobloc) in children as young as two years, adolescents and adults. This approach has provided predictable and stable results. It can be applied by itself or as an adjunct to traditional orthognathic and craniofacial surgical procedures. The technical aspects, including planning, surgical and orthodontic procedures, required to properly apply the technique are presented. For this severe group of patients the technique has been found to be simpler and safer than traditional surgical methods. Maxillary and midfacial advancement through distraction has been found to be extremely stable in the patients in whom the technique was used. The reasons for stability are discussed as well as the observed morphologic changes in the facial soft tissues, velopharyngeal mechanism and airway. However, challenges remain to be solved to improve all distraction techniques and the need for collaboration between researchers and clinicians is emphasized to maximize the benefits of this already promising and rewarding approach.

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.

Changes in speech following unilateral mandibular distraction osteogenesis in patients with hemifacial microsomia.

OBJECTIVE: The purpose of this study was to describe changes in articulation, resonance, and velopharyngeal function following mandibular distraction osteogenesis. DESIGN: This is a descriptive, post hoc study comparing the performance of patients on measures of articulation, resonance, and velopharyngeal function before and after mandibular distraction. SETTING: The data were collected at a tertiary health care center located in Chicago. PATIENTS: The clinical data from preoperative and postoperative evaluations of seven mandibular distraction patients were used. OUTCOME MEASURES: The outcome measures were number of articulation errors, severity of hypernasality and audible nasal emission, and velopharyngeal orifice size as estimated using the pressure-flow technique. RESULTS: Immediately after distraction, 28% (2/7) experienced a temporary deterioration in articulation and 42% (3/7) experienced a deterioration in nasal resonance. But by the long-term follow-up evaluation, all had returned to their preoperative levels. Pressure-flow test results generally support the perceptual findings. CONCLUSIONS: Patients being considered for mandibular distraction surgery should receive preoperative and postoperative speech evaluations and be counseled about risks for changes in their speech following surgery.

Radiographic evaluation of bone formation in the pterygoid region after maxillary distraction with a rigid external distraction (RED) device.

In recent years, distraction osteogenesis has been used to correct skeletal disharmonies in the craniofacial region including the mandible and maxilla. Rigid external distraction has been used successfully to correct severe maxillary skeletal discrepancies. However, the characteristics of the newly formed bone have not been studied. A modified tomogram technique was used to analyze the radiological characteristics of the bone generated after maxillary advancement with rigid external distraction. The newly developed protocol may assist the clinician to evaluate the distracted area and to determine the length of stabilization required after active treatment with rigid external distraction.

Soft tissue profile changes after maxillary advancement with distraction osteogenesis by use of a rigid external distraction device: a 1-year follow-up.

PURPOSE: This study was conducted to evaluate the soft tissue profile changes after maxillary advancement with distraction osteogenesis (DO). PATIENTS AND METHODS: Sixteen subjects underwent maxillary advancement with rigid external distraction after a high Le Fort I osteotomy. There were 11 male and 5 female patients, ages 5.2 to 25.7 years. The subjects included 9 with unilateral cleft lip and palate (UCLP), 4 with bilateral CLP, 2 with facial clefts and bilateral CLP, and 1 with cleft palate. Pretreatment and posttreatment lateral cephalograms were compared to evaluate the changes in soft tissue profile. A line 7 degrees below the SN plane was used as the horizontal coordinate, and a perpendicular line through Sella was used as the vertical coordinate in an XY coordinate system. RESULTS: The preoperative facial concavity (N'SnPg') was reduced by 15.59 degrees, and the nasal tip moved 3.75 mm forward and 2.05 mm upward. These changes were positively correlated with the change of ANS position. The soft-tissue-to-hard-tissue ratio was 0.53:1 for nasal tip and ANS. The ratio was negatively correlated with the age of the patient. The ratio of soft tissue A point to skeletal A point was 0.96:1 and for the incisal edge to vermilion border of the upper lip it was 0.8:1. The soft tissue B point and Pg did not change significantly with maxillary distraction. However, the nasolabial angle increased by 4.96 degrees, the upper lip curvature flattened by 0.65 mm, and the lower lip curvature was accentuated by 0.89 mm after distraction. The amount of upper incisal exposure increased from 1.1 to 5.01 mm in the rest position. CONCLUSION: Maxillary DO improved the soft tissue profile by increasing nasal projection, normalizing the nasolabial angle, and making the upper lip more prominent. More upper anterior tooth show in the rest position was obtained, but the upper lip length did not change. The concave facial profile became convex, with improved facial balance and aesthetics.

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.

Maxillary distraction osteogenesis: a two-dimensional mathematical model.

Patients with cleft lip and palate with severe maxillary retrusion usually have a mandible with anterior-superior autorotation and subsequent overclosure and loss of the vertical facial dimension. Maxillary distraction osteogenesis can correct the sagittal maxillomandibular relationship and should simultaneously reestablish vertical dimension through maxillary vertical height increase and clockwise rotation of the mandible to restore facial balance. We present a two-dimensional mathematical model in the sagittal plane, which reestablishes sagittal and vertical skeletal deficiencies and proper occlusal alignment for planning maxillary advancement with distraction osteogenesis in patients with cleft lip and palate. The model is illustrated in a case of a 13-year-old boy with a complete bilateral cleft lip and palate and severe maxillary retrusion. The two-dimensional mathematical model described in this article allows the surgeon and orthodontist to calculate in a simple and accurate way the ideal distraction vector to advance the maxilla to its desired position.

Biomechanical considerations in distraction of the osteotomized dentomaxillary complex.

The completely osteotomized dentomaxillary complex is essentially a free body constrained only by its soft tissue attachments. Therefore the line of action and point of application of any protractive force(s) used during distraction osteogenesis must be considered relative to its center of mass. This is in contrast to the nonsurgically separated dentomaxillary complex, which is a constrained body, and therefore the application of protractive force(s) must be considered relative to its center of resistance. These two centers are not coincident. With knowledge of the location of the center of mass, predictable protraction of the dentomaxillary complex can be achieved. In this study, the center of mass of an adult maxillary specimen osteotomized to emulate a Le Fort I osteotomy was determined. Protractive force(s) through the center of mass will produce linear advancement along its line of action. Protractive movement of the dentomaxillary complex can be adjusted downward and forward or upward and forward by locating the protractive force(s) line of action superior or inferior to the center of mass. A cleft patient is described wherein the surgically separated dentomaxillary complex is protracted downward and forward with a force vector superior to its approximate center of mass. This results in a predictable increase in overbite and overjet with negligible mandibular rotation.

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.

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.

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.

Velopharyngeal changes after maxillary advancement in cleft patients with distraction osteogenesis using a rigid external distraction device: a 1-year cephalometric follow-up.

The effect of maxillary advancement on speech may have benefits on articulation improvement but compromises velopharyngeal (VP) closure by increasing the nasopharyngeal distance. The purpose of this study was to evaluate the static VP anatomic changes on lateral cephalograms in patients who underwent maxillary advancement through distraction osteogenesis (DO) with a rigid external distraction device and to correlate these changes with clinical speech data. Twenty-two patients (5 female and 17 male) underwent maxillary advancement through DO utilizing a rigid external distraction device (age, 5.2 to 25.7 years) with various diagnoses, including 13 unilateral cleft lip and palate (CLP) patients, 5 bilateral CLP patients, 1 isolated cleft palate patient, 2 facial cleft patients, and 1 patient with craniosynostosis. Lateral cephalograms of preoperative, immediate postdistraction, and 1-year postdistraction were obtained for analysis. Speech evaluation was performed preoperatively, immediate postdistraction, and then at 6-month intervals, and included assessment of air pressure flow, hypernasality, and articulation. With an average amount of 8.9 mm maxillary forward advancement, 14% of patients (3 of 21) presented deterioration in hypernasality. However, 57% of patients (12 of 21) demonstrated improvement in articulation. The cephalometric analysis demonstrated an increase in nasopharyngeal depth by 8.5 mm (1:1 ratio with bony movement) and velar angle by 14.1 deg. The length of the soft palate remained unchanged. The need ratio (intersection of palatal plane and posterior pharyngeal wall-posterior nasal spine/posterior nasal spine--tip of uvula) worsens after distraction. The deterioration of hypernasality was related to the amount of forward distraction, especially in patients without a preexisting pharyngeal flap (PF). Speech evaluation is an important aspect concerning treatment planning for maxillary distraction. The increase in nasopharyngeal depth may compromise VP closure. The increase in velar angle was considered to be part of the compensation in the VP mechanism. An adverse effect of a preexisting PF on maxillary distraction was not observed; however, it prevented postoperative hypernasality.

Rigid external distraction: its application in cleft maxillary deformities.

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.

Nonsyndromal craniosynostosis: longitudinal outcome following cranio-orbital reconstruction in infancy.

This paper presents a prospective longitudinal outcome study on patients with nonsyndromal craniosynostosis who were treated with the contemporary craniofacial surgical techniques of suture release, cranial decompression, and cranial and orbital reconstruction and reshaping in infancy. Diagnosis, surgical treatment, and long-term results and complications are reviewed. Preoperative and long-term postoperative intracranial volumes in these patients were evaluated and compared with age and gender match controls throughout the period of the study. From July 1, 1990, to July 1, 1994, 25 patients with isolated nonsyndromal craniosynostosis underwent surgery of the deformity. Eight patients were excluded from the study based on incomplete postoperative computed tomography (CT) records. Of the 17 patients with long-term computerized records, 11 were boys and 6 were girls. The nonsyndromal craniosynostosis patients in this study include six with bilateral coronal craniosynostosis, six with unilateral coronal craniosynostosis, four with sagittal craniosynostosis, and one with metopic craniosynostosis. The average age at the time of surgery for all patients was 9 months, and the average age at the time of the latest follow-up CT scan for all patients in the study was 3.5 years. There were no perioperative complications in this series of patients including no bleeding, no infection, no wound healing complications, and no mortality. Bony fixation included a combination of wire osteosynthesis and rigid microfixation. All patients had only one surgical procedure for the correction of their deformity. Evaluation of both preoperative and long-term postoperative intracranial volume measurements in this series of patients revealed that these volume measurements were comparable with the gender match control groups at all ages throughout the study. The significance of these findings for this longitudinal outcome study is discussed.

Alternative techniques in rigid fixation of the craniomaxillofacial skeleton.

Rigid fixation techniques in pediatric craniofacial surgery have enhanced our clinical results by offering greater stabilization and control of bone grafts and osteotomized free segments of the craniofacial skeleton. A potential disadvantage of rigid fixation techniques in the growing craniofacial skeleton includes possible long-term growth restrictions, which have been demonstrated in various animal models. Our goal was to evaluate alternative fixation techniques in the growing craniofacial skeleton of the rabbit to study how altering fixation techniques affects craniofacial development. Eighty New Zealand White rabbits were used in this study. Rabbits were divided into eight groups of 10 each, and seven variant fixation techniques were used to stabilize the frontal bones after bifrontal craniectomies. In all groups except Group 1, the animals underwent a bifrontal craniectomy with orthotopic replacement of the frontal bones. Fixation for each group was as follows: Group 2, wire; Group 3, full microplate; Group 4, suture; Group 5, microplate removal at 4 weeks; Group 6, anterior plate; Group 7, posterior plate; Group 8, soft plate. It was demonstrated that long-term effects on craniofacial development in this animal model are significantly influenced by the type and location of rigid fixation hardware. Significant differences in growth of the craniofacial skeleton for the different fixation groups are presented and discussed.

Maxillary dental development in complete unilateral alveolar clefts.

OBJECTIVE: This study was conducted to determine whether development of individual maxillary teeth in subjects with complete unilateral alveolar clefts was significantly different from that found in unaffected children. DESIGN: Retrospective, mixed longitudinal. SETTING: Craniofacial Center, university based. MATERIALS AND METHODS: A sample of 179 panoramic radiographs obtained during the mixed dentition from 79 subjects (47 males, 32 females) with complete alveolar clefts was analyzed. After visual evaluation of root development of the permanent maxillary teeth from radiographs, a score from 0 to 5 was assigned utilizing a predefined scoring system. Statistical analyses were performed between the cleft and unaffected reference groups available in the literature. RESULTS: The cleft side dentition was found to be significantly delayed in development relative to the noncleft side (p < .05). Compared to the reference group, the cleft side lateral incisor demonstrated a mean difference in development of 1.59 years followed by the canine (1.39 years), the central incisor (0.96 years), the first premolar (0.94), and the second premolar (0.78). CONCLUSION: Teeth directly adjacent to the cleft site were shown to be the most delayed. The lateral incisors and canines were observed to be the most variable when compared to their corresponding antimeres. The information obtained from this study may assist the orthodontist in selecting the appropriate time to initiate orthodontic treatment in order to prepare the permanent dentition prior to alveolar bone grafting.

Distraction osteogenesis: the effects of orthodontic tooth movement on distracted mandibular bone.

The application of distraction osteogenesis in craniomaxillofacial surgery has created new treatment methods for patients with craniofacial skeletal dysplasias. Most of the applications in the craniofacial skeleton have been for the correction of severe congenital or acquired conditions. As more understanding is gained with these new approaches, refinements in techniques will enhance treatment planning and outcome. This will expand the application of distraction osteogenesis to more common, less severe types of skeletal dysplasias. One of the important areas in mandibular distraction osteogenesis is the management of the dental gap created when distraction is applied within the tooth-bearing segment of the mandibular body. In this study, the authors investigated the effects of orthodontic tooth movement into new bone created through the process of distraction osteogenesis. Orthodontic tooth movement through newly formed mandibular bone in the canine model was performed and, through histologic studies, was found to create compact bone along the path of the moving tooth. This compact bone replaced the more unstructured woven bone that was originally created by the process of mandibular distraction osteogenesis. These findings indicate that orthodontic tooth movement can be performed in distracted bone and can have significant influence on the stability and long-term structural preservation of the bone created by distraction osteogenesis within the tooth-bearing segment of the mandible.

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.

Longitudinal analysis of mandibular asymmetry in hemifacial microsomia.

Reconstruction of the mandible is one of the key elements in the skeletal rehabilitation of patients with hemifacial microsomia. Unfortunately, knowledge about long-term 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.