Distraction osteogenesis of the ascending ramus for mandibular hypoplasia using extraoral or intraoral devices: a report of 8 cases

Bilateral Biplanar Distraction Osteogenesis in Facial Deformity Secondary to Temporomandibular Ankylosis

Background

The purpose of this single-centre prospective clinical study was to evaluate the correction of severe facial deformity and Obstructive sleep apnoea hypopnoea syndrome (OSAHS) in 22 patients aged from 9 to 42 years (mean 20.09) of bilateral Temporomandibular joint ankylosis.

Materials and Methodology

Patients underwent multisegment distraction using external bilateral bidirectional distractors. Facial deformity was evaluated clinically in terms of mouth opening and neck chin angle and cephalometrically in terms of corpus length (gonion-pogonion), ramal height (articulare-gonion), chin deficiency (N perpendicular to Pog and SNB). OSAHS was evaluated through Epworth sleepiness scale, Berlin's questionnaire, pharyngeal airway space, apnoeic hypoapnoeic index, oxygen desaturation index, average arterial oxygen saturation and minimal fall in O2 saturation. Patients were followed up for a period of 13-74 months (mean 28.68).

Results

Statistically highly significant results were obtained in all parameters. Complications encountered were pin infection (13.63%), loosening of pins (4.5%), wound dehiscence (9.09%), tooth fracture (4.5%) and parotid fistula (9.09%). Intermediate segment necrosis and vector loss were not observed.

Conclusion

This study is a large case series using two corticotomy cuts for external bilateral bidirectional distracters with concomitant neo callous moulding in patients both pre- and post-ankylosis release. It is extremely efficient in correcting mandibular corpal and ramal deficiency as well as improving OSAHS.

Evaluation of use of distraction osteogenesis in mandibular retrognathia and its effect on soft and hard tissues and airway

Objectives:

Bone distraction is the process of new bone formation between the surfaces of bone segments gradually separated by incremental traction of soft tissues. These adaptive changes in the soft tissues allow for greater skeletal movements while minimizing the potential relapse. In this study, we are reporting our clinical experience with mandibular distraction used to achieve simultaneous skeletal and soft-tissue correction with distraction osteogenesis (DO).

Methodology:

A total of five patients who reported to the department for the treatment of mandibular deficiencies were selected. Cephalometric studies were done preoperatively and postoperatively for hard tissue assessment. Predefined reference points were used for the clinical evaluation for the evaluation of soft tissues. Results were compared between preoperative and 1^st-, 3^rd-, 6^th-, and 12^th-month postoperatively.

Results:

The clinical observations in our study showed that there is a remarkable improvement in the facial esthetics. Cephalometric analysis has shown lengthening of the mandibular corpus and increase in the height of the vertical ramus. Certain minimal complications have also been noted.

Conclusion:

Despite the few complications, DO has become a popular surgical modality due to its many advantages.

Technique of Dual Distraction for Correction of Unilateral Temporomandibular Joint Ankylosis With Facial Asymmetry: A Case Series

PURPOSE

Temporomandibular joint (TMJ) ankylosis, not only results in joint hypomobility, but also causes considerable facial deformity. Its unilateral variant can cause facial asymmetry, leading to major psychosocial effects on the individual.

PATIENTS AND METHODS

We present the cases of 7 patients with unilateral TMJ ankylosis and facial asymmetry of various grades who have been treated using gap arthroplasty and simultaneous dual distraction. Considerable debate has surrounded the sequencing of TMJ release and distraction osteogenesis; however, the simultaneous approach has recently become popular. The use of a single distractor simultaneously with TMJ release has been widely reported. However, one disadvantage with this technique is that the proximal condylar segment remains unstable. Dual distraction is a newer technique which we have proposed as a single-stage approach for the correction of TMJ ankylosis and facial asymmetry and to address the problems resulting from the use of a single distractor.

RESULTS

After treatment, all the patients showed a mouth opening ranging from 35 to 50 mm and satisfactory facial symmetry.

CONCLUSIONS

Dual distraction is a promising technique in the correction of facial asymmetry. However, further studies with adequate statistical analysis and larger sample size are required.

Role of extra oral monofocal distractor device in the correction of the facial asymmetry, sleep apnoea, and quality of life associated with TMJ ankylosis

OBJECTIVES

The purpose of this study is to evaluate the role of primary osteo-distraction prior to ankylosis release in patients, diagnosed with sleep apnoea, facial asymmetry, and reduced quality of life secondary to temporomandibular joint (TMJ) ankylosis.

METHODS

Ten patients in the age group of 13-40 years with TMJ ankylosis underwent primary osteo-distraction for mandibular advancement. They were evaluated pre- and post-operatively using radiographs, various questionnaires, and subjective evaluation of facial asymmetry, sleep apnoea, and quality of life (QOL).

RESULTS

All the ten patients showed significant improvement in their sleep apnoea symptoms with a mean of 6.20 ± 1.39 (P < 0.05). The mean advancement of the mandible in all the ten patients (both bilateral and unilateral ankylosis) was 15.8 mm (P < 0.05). The quality of life showed marked improvement from very poor to very satisfactory (P < 0.001).

CONCLUSION

Primary mandibular distraction is an effective method of correction of facial asymmetry, sleep apnoea, and quality of life in patients with TMJ ankylosis.

Defining the ascending ramus: A search

STATEMENT OF PROBLEM

Lack of an accepted definition for the ascending ramus of the mandible means no common reference point is available for clinical or research dialogue.

PURPOSE

The purpose of this review was to determine whether the ascending ramus has been defined, by using a search of published studies.

MATERIAL AND METHODS

PubMed was searched, using terms "ascending ramus" and "mandible."

RESULTS

The search found no acceptable definition of the ascending ramus of the mandible.

CONCLUSIONS

An acceptable definition for the ascending ramus of the mandible is lacking, and one is proposed here.

Management of Cleft Maxillary Hypoplasia with Anterior Maxillary Distraction: Our Experience

Maxillary hypoplasia is a common developmental problem in cleft lip and palate deformities. Since 1970s these deformities have traditionally been corrected by means of orthognathic surgery. Management of skeletal deformities in the maxillofacial region has been an important challenge for maxillofacial surgeons and orthodontists. Distraction osteogenesis is a surgical technique that uses body's own repairing mechanisms for optimal reconstruction of the tissues. We present four cases of anterior maxillary distraction osteogenesis with tooth borne distraction device-Hyrax, which were analyzed retrospectively for the efficacy of the tooth borne device-Hyrax and skeletal stability of distracted anterior maxillary segment.

In Vitro Mechanical Evaluation of Mandibular Bone Transport Devices

Bone transport distraction osteogenesis (BTDO) is a surgical procedure that has been used over the last 30 years for the correction of segmental defects produced mainly by trauma and oncological resections. Application of BTDO has several clinical advantages over traditional surgical techniques. Over the past few years, several BTDO devices have been introduced to reconstruct mandibular bone defects. Based on the location and outline of the defect, each device requires a uniquely shaped reconstruction plate. To date, no biomechanical evaluations of mandibular BTDO devices have been reported in the literature. The present study evaluated the mechanical behavior of three different shaped prototypes of a novel mandibular bone transport reconstruction plate and its transport unit for the reconstruction of segmental bone defects of the mandible by using numerical models complemented with mechanical laboratory tests to characterize strength, fatigue, and stability. The strength test evaluated device failures under extreme loads and was complemented with optimization procedures to improve the biomechanical behavior of the devices. The responses of the prototypes were characterized to improve their design and identify weak and strong regions in order to avoid posterior device failure in clinical applications. Combinations of the numerical and mechanical laboratory results were used to compare and validate the models. In addition, the results remark the importance of reducing the number of animals used in experimental tests by increasing computational and in vitro trials.

Bone regeneration and docking site healing after bone transport distraction osteogenesis in the canine mandible

PURPOSE

Bone transport distraction osteogenesis provides a promising alternative to traditional grafting techniques. However, existing bone transport distraction osteogenesis devices have many limitations. The purpose of this research was to test a new device, the mandibular bone transport reconstruction plate, in an animal model with comparable mandible size to humans and to histologically and mechanically examine the regenerate bone.

MATERIALS AND METHODS

Eleven adult foxhounds were divided into an unreconstructed control group of 5 animals and an experimental group of 6 animals. In each animal, a 34-mm segmental defect was created in the mandible. The defect was reconstructed with a bone transport reconstruction plate. Histologic and biomechanical characteristics of the regenerate and unrepaired defect were analyzed and compared with bone on the contralateral side of the mandible after 4 weeks of consolidation.

RESULTS

The reconstructed defect was bridged with new bone, with little bone in the control defect. Regenerate density and microhardness were 22.3% and 42.6%, respectively, lower than the contralateral normal bone. Likewise, the anisotropy of the experimental group was statistically lower than in the contralateral bone. Half the experimental animals showed nonunion at the docking site.

CONCLUSION

The device was very stable and easy to install and activate. After 1 month of consolidation, the defect was bridged with new bone, with evidence of active bone formation. Regenerate bone was less mature than the control bone. Studies are underway to identify when the regenerate properties compare with normal bone and to identify methods to augment bone union at the docking site.

Biomechanical characteristics of regenerated cortical bone in the canine mandible

To test the mechanical properties of regenerate cortical bone created using mandibular bone transport (MBT) distraction, five adult male American foxhound dogs underwent unilateral distraction of the mandible with a novel MBT device placed to linearly repair a 30-35 mm bone defect. The animals were sacrificed 12 weeks after the beginning of the consolidation period. Fourteen cylindrical specimens were taken from the inner (lingual) and outer (buccal) plates of the reconstructed mandible and 21 control specimens were removed from the contralateral aspect of the mandible. The mechanical properties of the 35 cylindrical cortical bone specimens were assessed by using a non-destructive pulse ultrasound technique. Results showed that all of the cortical mechanical properties exhibit higher numerical values on the control side than the MBT regenerate side. In addition, both densities and the elastic moduli in the direction of maximum stiffness of the regenerate cortical bone specimens are higher on the lingual side than the buccal side. Interestingly, there is no statistical difference between elastic modulus (E(1) and E(2) ) in orthogonal directions throughout the 35 cortical specimens. The data suggest that not only is the regenerate canine cortical bone heterogeneous, but the elastic mechanical properties tend to approximate transverse isotropy at a tissue level, as opposed to control cortical bone, which is orthotropic. In addition, the elastic mechanical properties are higher not only on the control side but also in the lingual anatomical position, suggesting a stress shielding effect from the presence of the reconstruction plate.

Biomechanical configurations of mandibular transport distraction osteogenesis devices

Mandibular bone transport (MBT) distraction osteogenesis devices are used for achieving reconstruction of mandibular defects in a predictable way, with few complications, less complexity than other alternative surgical procedures, and minimal tissue morbidity. However, selection of appropriate MBT device characteristics is critical for ensuring both their mechanical soundness and their optimal distraction function for each patient's condition. This article assesses six characteristics of currently available MBT devices to characterize their design and function and to classify them in a way that assists the selection of the best device option for each clinical case. In addition, the present work provides a framework for both the biomechanical conception of new devices and the modification of existing ones.

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

INTRODUCTION

Distraction osteogenesis has gained popularity because of the hypothesized concurrent soft-tissue expansion, which is believed to reduce postoperative relapse. Although many articles describe the immediate success of mandibular distraction, little research has been done on its long-term stability. Our goal was to examine the long-term craniofacial changes after distraction.

METHODS

Four hemifacial microsomic patients treated with unilateral mandibular distraction were recalled. Changes in maxillary width and height, occlusal height, ramus height, mandibular length, and chin position were quantified by using the posteroanterior and 45 degrees lateral oblique cephalographs. Predistraction and postdistraction measurements were taken over a 5-year period. The data were analyzed by using paired t tests and ANOVA.

RESULTS

Maxillary height, ramus height, mandibular length, and chin point deviation all experienced moderate improvement after distraction. Although the growth patterns between the control side and the treated side were comparable until 2 years after removal of the device, the normal side outgrew the affected side thereafter until 5 years after distraction.

CONCLUSIONS

Because of the greater inherent growth potential of the unaffected side, more overcorrection than originally believed is needed to offset the persistent asymmetry in growing hemifacial microsomia patients who undergo unilateral distraction osteogenesis.

Meta-analysis of mandibular distraction osteogenesis: clinical applications and functional outcomes

BACKGROUND

Mandibular distraction osteogenesis has been used effectively to treat syndromic craniofacial deformities. In recent years, its scope of application has widened to include treatment of airway obstruction in adults and children and nonsyndromic class II mandibular hypoplasia. So far, there has been no evidence-based review of mandibular distraction osteogenesis for mandibular lengthening.

METHODS

Two rounds of searches were performed by two independent assessors. The first-round PubMed search used the keywords "mandible" and "distraction osteogenesis." In the second-round search, the reference lists of the articles were retrieved. For both rounds, abstracts and then full articles were reviewed and selected on the basis of a set of inclusion and exclusion criteria.

RESULTS

The 178 retrieved articles yielded 1185 mandibular distraction osteogenesis patients: 539 received unilateral mandibular distraction osteogenesis and 646 received bilateral mandibular distraction osteogenesis. Mandibular distraction osteogenesis was reported to improve facial asymmetry and retrognathia (50.1 percent), correct the slanted lip commissure (24.7 percent), and improve or level the mandibular occlusal plane (11.1 percent) in unilateral asymmetry cases, whereas bilateral mandibular distraction osteogenesis was shown to be effective in preventing tracheostomies for 91.3 percent of neonates or infants with respiratory distress, and in relieving symptoms of obstructive sleep apnea for 97.0 percent of children and 100 percent of adult patients.

CONCLUSIONS

Mandibular distraction osteogenesis is effective in treating craniofacial deformities, but further clinical trials are required to assess the long-term stability and to compare the treatment with conventional treatment methods, especially in cases of obstructive sleep apnea or class II mandibular hypoplasia.

Intraoral distraction osteogenesis for the correction of facial deformities following temporomandibular joint ankylosis: a modified technique

The aim of this study was to evaluate the feasibility of transoral bimaxillary distraction osteogenesis before releasing temporomandibular joint (TMJ) ankylosis using intraoral mandibular distractors. Nine patients (5 males, 4 females) aged 14-35 (mean 19) years were included. A bilateral Le Fort I osteotomy was performed together with a mandibular osteotomy on the affected side(s). An intraoral distractor(s) was inserted in the lower jaw, followed by an intermaxillary fixation (IMF) to maintain preoperative dental occlusion. The distractor was activated, after a latency period of 5-7 days, 2 times daily by 0.5 mm. There followed a consolidation period of 6-8 weeks. TMJ ankylosis was then released via a peri-auricular incision, a gap arthroplasty was performed, and mandibular movement was established after removal of the IMF and distractor. Optimal results were achieved clinically and radiologically with minimal relapse and complications. Apart from minor complaints, the distraction process was smooth and tolerable in all cases. Total mandibular elongation ranged from 17 to 25 mm (20.7 mm). Occlusal canting decreased to 0 degrees in 7 patients and to 1 degree in 2 patients (mean 0.2 degrees). After a mean follow-up period of 17 months, a mean postoperative mouth opening of 34.7 mm was achieved (0.6 mm preoperatively) and no re-ankylosis was detected. Intraoral distraction of a deformed mandible and maxilla before releasing TMJ ankylosis is a feasible and perhaps advantageous technique.

Outcome measurement in the correction of mandibular asymmetry

This study related clinical assessments of the severity of mandibular asymmetry with computerized measurements, obtained by digitizing mandibular outlines from standardized facial photographs. Four ratios were calculated: area (size), compactness (shape), perimeter (length of outline), and moment (center of area). When comparing clinical severity with computer assessment, significant correlations were observed; those for area and compactness were the highest. Sixteen patients subsequently underwent corrective surgery, and their ratios were used to relate the degree of improvement to the original severity of the asymmetry. The posttreatment ratios were also used to audit the outcome, comparing the patients' scores as a group with results previously obtained from patients with normal symmetry and mild asymmetry. Posttreatment outcomes were significantly different from the normal outline group but were comparable with outcomes of patients with mild mandibular asymmetry. The system provided a sensitive, noninvasive method of assessing treatment change and could be useful in providing an objective means of quantifying treatment outcomes.

Cephalometric evaluation of the craniofacial complex in patients treated with an intraoral distraction osteogenesis device: a preliminary report

The purpose of this pilot study was to evaluate cephalometrically the efficacy of an intraoral distraction osteogenesis device in treating patients with unilateral mandibular hypoplasia. Six patients with hemifacial microsomia underwent unilateral mandibular distraction. Posteroanterior and 45 degrees lateral oblique cephalograms were measured, and changes in maxillary width and height, occlusal height, ramus height, mandibular length, and chin position were quantified. Measurements were taken preoperatively and postoperatively at 7 time points (T1-T7) over 2 years. Calculations for statistical significance were done to T6 for all patients and through T7 for 4 patients. The means and variances were calculated for the 6 cephalometric variables for each time point. The mean differences between treatment and control were calculated as well as analysis of variance. Mean differences between specific time periods were measured by pairwise comparison with significance determined at the 0.05 level of confidence. Statistical analysis was used for descriptive purposes only. The cephalometric data suggest that the intraoral distractor is as capable of lengthening hypoplastic mandibles as the initial extroral appliances. The bone lengthening appears stable, with the distracted side of the mandible maintaining a growth rate similar to the normal side. Immediately after distraction, transient improvements were noted in maxillary height, ramal height, and maxillary width. All patients demonstrated an immediate improvement in chin position toward the skeletal midline; however, after T4, menton appeared to be moving away from the midline over time.

Pediatric Mandibular Distraction Osteogenesis: The Present and the Future

Pediatric mandibular distraction osteogenesis (MDO) has become a mainstay of treatment for patients with micrognathia and retrognathia. As craniofacial surgeons have gained experience with MDO, the technique has become a safe and durable means of mandibular lengthening that avoids the significant morbidity of conventional surgical treatments. The full impact of this technique has not yet been realized for pediatric patients. Although studies have confirmed durable reconstruction of mandibular length with MDO, the range of applications of this technique is currently limited. As innovative clinicians continue to apply MDO to pediatric clinical craniofacial problems not easily treated with conventional means, the field of MDO will continue to mature. This article discusses current uses and examples of potential future applications of pediatric MDO. The development of novel and creative applications of MDO will advance the management of complex craniofacial anomalies, taking the field of craniofacial surgery into the future.

Mandibular distraction osteogenesis using an intraoral device and bite plate for a case of hemifacial microsomia

OBJECTIVE

To present orthodontic treatment combined with mandibular distraction osteogenesis using an intraoral device and a bite plate in a patient with hemifacial microsomia, severe facial asymmetry, and unilateral mandibular hypoplasia.

PATIENT

An 8-year-old girl exhibited mandibular deviation resulting from hypoplasia of the mandibular condyle and ramus on the left side. The patient was treated with an intraoral device for mandibular distraction osteogenesis, bite plate, and hybrid-type functional appliance. Facial asymmetry was improved, and the mandibular ramus was elongated in an anterior and primarily posterior direction with slightly posterior and superior displacement of the proximal segment. Postdistraction treatment results have been stable for 1 year. At the 1-year follow-up, the volume of the lateral and medial pterygoid muscles on the left side had increased. The condyle and disc on the right temporomandibular joint moved well and in harmony at open mouth position, and a rotational movement of the left temporomandibular joint was observed.

Effects of mandibular distraction osteogenesis on the inferior alveolar nerve: an experimental study in monkeys

A series of experimental studies were performed in monkeys to study the effect of mandibular distraction osteogenesis on the inferior alveolar nerve at different times before and after distraction. A mandible osteotomy was performed and distraction was carried out unilaterally in 10 young rhesus monkeys and bilaterally in six. The intact nerves on the contralateral side of the 10 monkeys were used for the control. Care was taken to avoid destroying the integrity of the inferior alveolar nerve during the surgical procedure. After a 5-day latency period, the distraction device was activated at a rate of 0.5 mm twice each day for 15 days. Sensory nerve action potential testing was applied before and 1 day after the operation, at completion of distraction, and at 2, 4, 6, 9, and 12 weeks of fixation. Necropsy was performed at the completion of distraction and 2, 4, 6, and 12 weeks of fixation. The mental nerves were taken, sectioned, and stained with lead citrate and uranyl acetate, and examined with a transmission electron microscope. The inferior alveolar nerves in the distraction gap were obtained, and paraffin slides were made and stained with hematoxylin and eosin, Luxol fast blue, and Bodian methods. The authors found that immediately after the mandible osteotomy, most nerves showed signs of slight acute injury; the latency was increased by 5.553 percent, and the amplitude was decreased to 1808 microV. This might be caused by the surgical procedure or by compressions produced by swelling tissues around the nerves. When distraction was completed, the latency was prolonged for an average of 22.18 percent, and the amplitude average had attenuated to 28.54 percent (804 microV) of the preoperative value on the distracted side. Most nerve fibers exhibited signs of degeneration, such as myelin disruption, swelling of cell organs greatly increased in axoplasm, axon tearing, and myelin fragments engulfed by macrophages. These were nerve reactions to the tensions produced by mandible lengthening. As time elapsed, the nerve's action potential recovered gradually because of its repairing ability, the latency shortened, amplitude increased, Schwann cells proliferated and formed new myelin sheaths, and the tearing axons reconnected. After 12 weeks of consolidation, there was still a latency of 12.384 percent prolongation because of the prolonged conduction distance, and the average amplitude was restored to 2786 microV, the approximate preoperative value. The nerve seemed to be repaired completely; its myelin thickness, axon diameter, and ultrastructure were all similar to those of the control. It was concluded that mandibular distraction osteogenesis can produce some degree of harmful effects on the function and structure of inferior alveolar nerves, but it is reversible and relatively slight. Along with the regeneration of the nerve's myelin and axon, the nerve function can gradually rehabilitate to a normal level.

Do position and soft tissue affect distraction vector? An in vitro investigation

OBJECTIVES

The purpose of this investigation was to provide an in vitro evaluation of the effects of soft tissue and position on vector during distraction.

MATERIALS AND METHODS

A polyurethane skull and mandible replica (Synbone, Landquart, Switzerland) was used in this study along with an internal distraction device (Synthes Maxillofacial, Paoli, PA). The first portion of the investigation evaluated the effects of distractor position (inferior body, midbody, and superior body) on distraction vector. The second portion of the investigation used polyethylene straps to simulate the suprahyoid muscles and muscles of mastication, and polysulfide to simulate periosteum and mucosa. A laser light source attached to the synthetic mandible was projected on a grid 7.1 m from the construct to measure deflection from the starting point. The distractor was advanced 8.0 mm for each trial. Five trials each for inferior, middle, and superior, with and without simulated soft tissues (N = 30) were performed. Vertical and horizontal deflection along with absolute distance were measured and recorded. Means and standard deviations were derived for groups, and compared for statistical significance (P <.05) with a 1-way analysis of variance for the effects of position with and without simulated soft tissue, and with a paired t-test for the effects of simulated soft tissue within groups of similar distractor position.

RESULTS

Statistically significant differences (P <.05) for distractors without simulated soft tissues were only noted for vertical deflection between the inferior and superior distractor groups. Statistically significant differences were noted for all measures, for all distractor positions with simulated soft tissues. Statistically significant differences were noted for all measures between similar distractor positions with and without simulated soft tissues. Distractors without simulated soft tissues were deflected lateral to the y-axis and above the x-axis. Distractors with simulated soft tissues were deflected lateral to the y-axis, but below the x-axis. For distractors with simulated soft tissues, the closer to the inferior border, the less the deflection from the x-axis.

CONCLUSION

Position alone had minimal effects on distraction vector. Simulated soft tissues affected the vector of distraction. The combination of position and simulated soft tissues affected distraction vector.

Hemifacial microsomia. Etiology, diagnosis and treatment

BACKGROUND

Three percent of all newborns have significant structural anomalies. Hemifacial microsomia, or HFM, is the second most common facial anomaly, second only to cleft lip and palate. New therapeutic and clinical management techniques offer promising interventions that can allow many patients to have more normal childhoods at earlier ages.

DESCRIPTION

Due to a unilateral deficiency of the mandible and lower face, patients who have HFM have specific dental needs that require restorative, orthodontic and surgical correction.

CLINICAL IMPLICATIONS

Oral and maxillofacial malformations present diagnostic and treatment challenges unique to the dental profession. The etiology, diagnosis and treatment modalities discussed in this article can be used to help effectively rehabilitate patients who have HFM.

Intraoral mandibular distraction osteogenesis: special attention to treatment planning

PURPOSE

To demonstrate our experience using internal devices for unidirectional distraction osteogenesis in treating different mandibular hypoplasias (with or without maxillary deformities). An algorithmic table for diagnosis, and treatment planning is presented.

PATIENTS AND METHODS

Twenty internal distraction devices were used in 16 patients with mandibular hypoplasia. Deficiency in length of the mandible was calculated on three-dimensional computed tomography scans. The device was activated by a transcutaneous pin on the fifth postoperative day. Distraction was achieved at rates of 0.5 mm/12 h. After a variable period of consolidation the devices were removed. Mean follow-up was 18 months.

RESULTS

Successful distraction osteogenesis was achieved in all patients. No premature consolidation or pseudoarthrosis was observed. Improvement of facial aesthetics was produced in all cases. Final occlusion was excellent in those cases where no simultaneous maxillary deformity was present. Orthodontic treatment was applied in all cases. Results remained stable one year postoperatively.

CONCLUSIONS

The occlusal results obtained in this series show that we can plan distraction as a definitive treatment in cases with isolated mandibular hypoplasia. When an additional maxillary deformity is present, mandibular distraction must be performed first if indicated, but a maxillary procedure will be necessary later.

Mandibular angle augmentation with the use of distraction and homologous lyophilized cartilage in a case of morphing to Michael Jackson surgery

Correction of an ill-defined mandibular angle is not an easy task, whether it is requested by the "congenital, orthognathic or cosmetic" patient. Deliberate over-correction has not been reported to our knowledge. This article presents a combination of distraction osteogenesis and lyophilized cartilage used to three-dimensionally over-augment the mandibular angle of a long-face prognathic patient who had the wish to be morphed to Michael Jackson or at least as far as current technique and his endogenic features allowed.