Maxillary Distraction Osteogenesis Combined with Mandibular Osteotomy to Correct Asymmetry of the Maxillomandibular Complex

Outcome analysis of biplanar mandibular distraction in adults

BACKGROUND

Mandibular deficiency leading to facial asymmetry causes cosmetic deformity as well as psychological stigma for the patient. Correction of these mandibular asymmetries is a major challenge. The study investigates the efficacy of bidirectional mandible distraction for the treatment of mandibular deficiency.

METHODS

This prospective study included six individuals aged between 17 and 24.4 years. Five patients had hemifacial microsomia and one had unilateral temporomandibular joint ankyloses. All patients underwent mandibular distraction osteogenesis. Postoperative skeletal changes in affected mandible, and changes in occlusal plane and oral commissure cant were evaluated using three-dimensional reconstruction. Patient satisfaction and understanding of the procedure were assessed through three questionnaires administered during pre-distraction, distraction and postdistraction phases.

RESULTS

In pre-distraction phase, aesthetic appearance seemed to be the primary indication for surgery. In distraction phase, pain while chewing was the primary handicap. In post-distraction phase all patients were satisfied with the aesthetic outcome. The facial deformity was improved through mandibular distraction osteogenesis. On the affected side in all the patients, height and length of the mandible increased. Canting of the occlusal plane and oral commissure was corrected.

CONCLUSION

Bidirectional mandible distraction is an effective treatment for correction of mandible deformities in adult patients.

Hemifacial microsomia treated with a hybrid technique combining distraction osteogenesis and a mandible-guided functional appliance: Pilot study

INTRODUCTION

The purpose of this study was to evaluate the therapeutic effect of a hybrid treatment for hemifacial microsomia that combines distraction osteogenesis and a mandible-guided functional appliance to correct mandibular asymmetry.

METHODS

This was a retrospective analysis of 10 patients with unilateral hemifacial microsomia who underwent mandibular ramus distraction osteogenesis in our hospital from February 2013 to July 2015. The cases were classified into 2 comparison groups: 5 patients were in the MG-DO group (distraction osteogenesis combined with an mandible-guided functional appliance) and 5 in the control group (distraction osteogenesis only). Anteroposterior cephalometric analyses were conducted before and after treatment. Soft tissue symmetry and the occlusal relationship were observed from facial and intraoral photographs. Statistical analyses were performed to determine changes between before and after treatment as well as intergroup differences.

RESULTS

The MG-DO group showed greater vertical elongation of the mandibular ramus and less overcorrection and mandibular deviation than the control group. Occlusal reconstruction was enabled by the mandible-guided functional appliance owing to a decrease in lateral shifting. The symmetry of both skeletal and soft tissues was significantly improved in the MG-DO group.

CONCLUSIONS

The hybrid technique combining distraction osteogenesis and the mandible-guided functional appliance proved to be effective in correcting canting and deviation during mandibular elongation, which improved facial symmetry and occlusal balance in patients with hemifacial microsomia.

Combined Bimaxillary Distraction Osteogenesis Associated with Orthognathic Surgery for Hemifacial Microsomia in Adults

BACKGROUND

Hemifacial microsomia (HFM) is one of the most common congenital craniofacial asymmetries. Distraction osteogenesis (DO) is always recommended as an effective option for the treatment of HFM, but some studies showed that the asymmetry remained after DO. In comparison with DO, stable clinical outcomes could be achieved by orthognathic surgery approach as well. However, soft tissue expansion cannot be performed. In this study, we aim to assess the radiographic and clinical results of bimaxillary DO associated with staged orthognathic surgery in the treatment of craniofacial asymmetry for adult HFM patients.

METHODS

Twelve HFM patients who had been treated with bimaxillary DO and secondary orthognathic surgery between 2006 and 2013 were included in this study. Bimaxillary DO and staged orthognathic surgery were performed according to the particular condition. Clinical and cephalometric photographs were carried out pre- and postoperatively to evaluate the outcomes.

RESULTS

No significant complications occurred postoperatively. Excellent cosmetic outcomes such as notable improvement in facial pattern and occlusion were achieved. Cephalometrically, the height ratios of the affected/unaffected ramus were improved by 23.81% on average, and the photographic analysis demonstrated a rotation of the chin point toward the mid-line. Moreover, the occlusal cant was corrected from the slant to level by 8.95° on average.

CONCLUSION

The application of bimaxillary DO associated with staged orthognathic surgery in correcting the asymmetry of adult patients with HFM could have satisfactory aesthetic results, and it should be considered an alternative option for these patients.

LEVEL OF EVIDENCE IV

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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.

Unilateral mandibular hypoplasia in adult patients: distraction osteogenesis and conventional osteotomies in a standardized sequence

INTRODUCTION

This study analyzed the outcomes of nongrowing patients with unilateral mandibular hypoplasia treated according to a specific protocol, which combines distraction osteogenesis, orthodontic treatment, and conventional osteotomies.

MATERIALS AND METHODS

The patients treated were objectively evaluated. Patient's satisfaction was assessed by questionnaire. Surgical changes were analyzed using cephalometry and three-dimensional facial surface data before surgery (T0) and at long-term (T1) follow-up.

RESULTS

Four patients were included in this study. The normalization of facial proportion and a high increase in symmetry were evident. Residual defects were documented in the postoperative symmetry of the chin. In the questionnaire, all patients gave favorable responses to their facial changes; for most of the objective parameters, all patients improved.

CONCLUSIONS

A multistage treatment protocol for the correction of facial deformities in patients with unilateral mandibular hypoplasia is a valid procedure for skeletal and occlusal stability. An evident improvement of the facial appearance is also achieved.

Modified animal model and computer-assisted approach for dentoalveolar distraction osteogenesis to reconstruct unilateral maxillectomy defect

PURPOSE

The purpose of this report is to show the establishment of an animal model with a unilateral maxilla defect, application of virtual reality and rapid prototyping in the surgical planning for dentoalveolar distraction osteogenesis (DO).

MATERIALS AND METHODS

Two adult dogs were used to develop an animal model with a unilateral maxillary defect. The 3-dimensional model of the canine craniofacial skeleton was reconstructed with computed tomography data using the software Mimics, version 12.0 (Materialise Group, Leuven, Belgium). A virtual individual distractor was designed and transferred onto the model with the defect, and the osteotomies and distraction processes were simulated. A precise casting technique and numeric control technology were applied to produce the titanium distraction device, which was installed on the physical model with the defect, which was generated using Selective Laser Sintering technology, and the in vitro simulation of osteotomies and DO was done.

RESULTS

The 2 dogs survived the operation and were lively. The osteotomies and distraction process were simulated successfully whether on the virtual or the physical model. The bone transport could be distracted to the desired position both in the virtual environment and on the physical model.

CONCLUSIONS

The novel method to develop an animal model with a unilateral maxillary defect was feasible, and the animal model was suitable to develop the reconstruction method for unilateral maxillary defect cases with dentoalveolar DO. Computer-assisted surgical planning and simulation improved the reliability of the maxillofacial surgery, especially for the complex cases. The novel idea to reconstruct the unilateral maxillary defect with dentoalveolar DO was proved through the model experiment.