Cephalometric evaluation of the craniofacial complex in patients treated with an intraoral distraction osteogenesis device: a long-term study

Evaluation of post-activation mandibular remodelling in children with craniofacial microsomia treated with distraction osteogenesis

OBJECTIVE

Patients with type IIA craniofacial microsomia (CFM) may benefit from mandibular distraction osteogenesis (MDO) treatment during childhood; however, remodelling of the mandible during the consolidation phase, which may affect the short-term outcomes of MDO, has not yet been quantitatively analysed using computed tomography. Therefore, we aimed to investigate bone remodelling of the mandible in children with type IIA CFM treated with MDO before distractor removal and the factors that influence ramus vertical elongation efficiency.

MATERIALS AND METHODS

Twenty-three children with unilateral CFM were studied between 2020 and 2024. Longitudinal computed tomography data (preoperative, end of active phase and at pre-distractor removal) were analysed. Condyle positions and the mandibular cant were analysed using a paired-sample t test. The relapse rates of vertical lengthening and mandibular cant were calculated. The correlation between distraction efficiency and preoperative craniofacial morphology was analysed.

RESULTS

The condyle on the affected side moved upwards and backwards by 28.84 ± 4.08 and 2.85 ± 4.33 mm, respectively during the active phase but lost 7.66 ± 2.64 mm of vertical extension during the consolidation phase. The relapse rates for vertical extension of the condyle and occlusal plane were 27% and 35%, respectively. The ratio of mandibular ramus height was positively related to EV.

CONCLUSIONS

In children with CFM, attention should be paid to vertical elongation instability and relapse of mandibular inclination during consolidation. Severe mandibular ramus hypoplasia is a preoperative risk factor for vertical skeletal relapse during consolidation. Further efforts are required to reduce the stress that leads to relapse.

Non-progressive mandibular changes in children with Type I and II craniofacial microsomia

OBJECTIVE

To describe the mandibular growth of craniofacial microsomia (CFM) patients during early childhood to adolescence with attention to symmetry.

MATERIALS AND METHODS

Altogether 61 CFM patients were studied at the Cleft Palate and Craniofacial Center, Helsinki University Hospital between 1986 and 2006. In this cohort study, we measured and analysed 293 radiographs (posteroanterior, panoramic and lateral); 165 radiographs of 40 patients met the final inclusion criteria. The vertical height of the ramus in anteroposterior and panoramic radiographs, the length of the mandible in anteroposterior radiographs and the maxillary protrusion and mandibular retrognathia in lateral cephalograms were measured in four different age groups.

RESULTS

A statistical difference existed between the groups in the vertical height of the ramus and in the mandibular length. The vertical height of the ramus measured from the panoramic radiograph grew on both sides, and the ratios remained unchanged. In the sagittal dimension, the maxilla and mandible grew forward, but no significant differences emerged between the groups.

CONCLUSIONS

Results suggest that mild-type CFM is not progressive in nature. During growth, mandibular asymmetry measured in the horizontal, vertical and sagittal planes did not increase.

Growth characteristics and classification systems of hemifacial microsomia: a literature review

BACKGROUND

Hemifacial microsomia is characterized by the hypoplasia of the mandible and temporomandibular joint, involving a variety of abnormalities of the craniofacial area. Since it gradually worsens as patients grow, it is necessary to understand the characteristics of facial bone growth and facial deformity in hemifacial microsomia patients in order to determine appropriate treatment timing and treatment methods.

MAIN BODY

Appropriate classification of hemifacial microsomia would facilitate accurate diagnosis, selection of treatment methods, and prognosis prediction. Therefore, in this article, we review previously published hemifacial microsomia classification and provide an overview of the growth of the facial skeleton and the characteristics of hemifacial microsomia-related facial deformities. The OMENS system is the most comprehensive classification method based on the characteristics of hemifacial microsomia deformity, but it needs to be improved to include malar/midface abnormalities and nerve involvement. In hemifacial microsomia, growth is progressing on the affected side, but to a lesser degree than the unaffected side. Therefore, surgical intervention in growing patients should be performed selectively according to the severity of deformity.

CONCLUSION

Understanding growth patterns is important to develop appropriate treatment protocols for correcting asymmetry in adult patients and to minimize secondary anomalies in growing patients.

Quantitative structural analysis of hemifacial microsomia mandibles in different age groups

Introduction

This study aims to quantitively analyze mandibular ramus and body deformities, assessing the asymmetry and progression in different components.

Methods

This is a retrospective study on hemifacial microsomia children. They were divided into mild/severe groups by Pruzansky-Kaban classification and into three age groups (<1 year,1-5 years, 6-12 years old). Linear and volumetric measurements of the ramus and the body were collected via their preoperative imaging data to compare between the different sides and severities, using independent and paired tests, respectively. The progression of asymmetry was assessed by changes in affected/contralateral ratios with age using multi-group comparisons.

Results

Two hundred and ten unilateral cases were studied. Generally, the affected ramus and body were significantly smaller than those on the contralateral side. Linear measurements on the affected side were shorter in the severe group. Regarding affected/contralateral ratios, the body was less affected than the ramus. Progressively decreased affected/contralateral ratios of body length, dentate segment volume, and hemimandible volume were found.

Discussion

There were asymmetries in mandibular ramus and body regions, which involved the ramus more. A significant contribution to progressive asymmetry from the body suggests treatment focus in this region.

A new treatment strategy for hemifacial microsomia: Auricular reconstruction with an expanded two-flap method and simultaneous mandibular distraction osteogenesis

BACKGROUND

Owing to the complex clinical manifestations of hemifacial microsomia (HFM), multidisciplinary cooperation is required to achieve better therapeutic effects in terms of function and aesthetics. This study aimed to explore the efficacy of the expanded two-flap auricular reconstruction combined with mandibular distraction osteogenesis in the treatment of HFM.

METHODS

This surgical strategy was performed in three stages. In the first stage, the retroauricular skin was expanded with a tissue expander and a mandibular distraction device was installed. In the second stage, the traditional expanded two-flap method for auricular reconstruction was adapted, and the framework was fabricated with costal cartilage and wrapped with the expanded skin flap, retroauricular fascia flap, and full-thickness skin graft. In the final stage, the tragus and lobule were rebuilt, the concha cavity deepened, and the mandibular distraction device removed.

RESULTS

From January 2014 to November 2018, 166 HFM patients underwent auricular reconstruction with the expanded two-flap method and simultaneous mandibular extension in our hospital. The median follow-up period was 9.3 months. Of the 166 patients, 154 patients and their families were satisfied with the results, and only 16 patients experienced complications.

CONCLUSIONS

This three-stage technique of simultaneous auricular reconstruction and mandibular distraction osteogenesis is safe and effective in achieving facial symmetry, improving occlusal contact, shortening treatment course, and relieving patient's suffering, especially for HFM patients.

The Association of External and Middle Ear Anomaly and Mandibular Morphology in Congenital Microtia

OBJECTIVE

To investigate the relationship between the severity of ear anomaly and mandibular dysplasia in congenital microtia.

STUDY DESIGN

Retrospective case review.

SETTING

Sapporo Medical University Hospital.

PATIENTS

Congenital microtia: 44 patients over a period of 4 years.

INTERVENTIONS

The height of the condylar process of the mandible was assessed by three-dimensional computed tomography (CT), and the patients were divided into three groups based on the ratio of the condylar process height on the affected side to that on the unaffected side: Group A, ≥1.00; Group B, 0.99 to 0.85; Group C, <0.85. Developmental abnormalities of the ear were evaluated using Jahrsdoerfer's scoring system on high-resolution CT scans.

MAIN OUTCOME MEASURES

Nonparametric statistical tests were used to determine correlations between the height of the condylar process of the mandible and Jahrsdoerfer's score.

RESULTS

The total Jahrsdoerfer's score for each group was 7.36 ± 2.23, 7.28 ± 0.10, and 4.52 ± 0.30, respectively; this value was significantly lower in Group C than in the other groups. In terms of subtotal points, oval window open, middle ear aeration, and mastoid pneumatization correlated significantly with mandibular dysplasia. Patients in Group C tended to have grade III microtia, by Marx's classification. Facial nerve weakness was not significantly correlated with mandibular dysplasia.

CONCLUSIONS

In congenital microtia, mandibular development correlated significantly with aeration of the middle ear space, pneumatization of the mastoid, and formation of the oval window, but not with the presence of a bony part of the external auditory canal or with ossicular development.

Combined maxillary and mandibular distraction osteogenesis in patients with hemifacial microsomia

INTRODUCTION

Hemifacial microsomia is a deformity of variable expressivity with unilateral hypoplasia of the mandible and the ear. In this study, we evaluated skeletal soft tissue changes after bimaxillary unilateral vertical distraction.

METHODS

Eight patients (4 preadolescents 4 adolescents) each with a grade II mandibular deformity underwent a LeFort I osteotomy and an ipsilateral horizontal mandibular ramus osteotomy. A semiburied distraction device was placed over the ramus, and intermaxillary fixation was applied. Anteroposterior cephalometric and frontal photographic analyses were conducted before and after distraction. Statistics were used to analyze the preoperative and postoperative changes.

RESULTS

Cephalometrically, the nasal floor and the occlusal and gonial plane angles decreased. The ratios of affected-unaffected ramus and gonial angle heights improved by 15% and 20%, respectively. The position of menton moved toward the midline. The photographic analysis showed a decrease of the nasal and commissure plane angles, and the chin moved to the unaffected side. The parallelism between the horizontal skeletal and soft tissue planes improved, with an increase in the affected side ramus height and correction of the chin point toward the midline.

CONCLUSIONS

Simultaneous maxillary and mandibular distraction improved facial balance and symmetry. Patients in the permanent dentition with fixed orthodontic appliances and well-aligned dental arches responded well to this intervention.

Maxillary molar intrusion with zygomatic anchorage in open bite treatment: lateral and oblique cephalometric evaluation

PURPOSE

We aimed to use lateral and oblique radiographs to evaluate dental and skeletal changes arising from maxillary molar intrusion with zygomatic anchorage in open bite patients.

METHODS

We conducted a pilot study including nine patients (six females and three males; mean age, 18.7 ± 5.1 years) with skeletal open bite treated with titanium miniplates for posterior dentoalveolar intrusion. Lateral and oblique (right and left, 45°) radiographs were obtained before (T1) and 6 months after intrusion (T2). A paired t test was used for statistical evaluation.

RESULTS

The maxillary posterior teeth were intruded 2.03 ± 0.87 mm (p < 0.01) with 450×g of force, which resulted in counterclockwise rotation of the mandible (1.57°, p = 0.02) and clockwise rotation of the occlusal plane (4.27 ± 2.66°, p = 0.01). Anterior facial height decreased by a mean of 1.79 ± 1.51 mm (p < 0.01). No significant change in the palatal plane or in anteroposterior molar movement was observed.

CONCLUSION

The oblique radiograph at 45° was useful for the assessment of molar intrusion and anteroposterior displacement. The treatment of anterior open bite with skeletal anchorage provided intrusion of molars and counterclockwise rotation of the mandible, resulting in open bite closure.