Mandibular distraction osteogenesis in a skeletal Class II patient with obstructive sleep apnea

Mandibular Endochondral Growth Is Specifically Augmented by Nutritional Supplementation with Myo-Inositol Even in Rabbits

Mandibular retrognathism occurs by insufficient mandibular growth and causes several issues, such as respiratory difficulty and diminished masticatory function. At present, functional orthodontic appliances are used for stimulating mandibular growth in pediatric cases. However, the effectiveness of functional appliances is not always stable in daily practices. A more effective, reliable, and safer therapeutic method for mandibular growth promotion would be helpful for growing mandibular retrognathism patients. As we previously discovered that nutritional supplementation of myo-inositol in growing mice specifically increases mandibular endochondral growth, we performed preclinical animal experiments in rabbits in this study. Briefly, six-week-old male Japanese white rabbits were fed with or without myo-inositol supplementation in laboratory chow until 25 weeks old, and 3D image analysis using micro CT data and histological examinations was done. Myo-inositol had no systemic effect, such as femur length, though myo-inositol specifically augmented the mandibular growth. Myo-inositol increased the thickness of mandibular condylar cartilage. We discovered that the nutritional supplementation of myo-inositol during the growth period specifically augmented mandibular growth without any systemic influence, even in rabbits. Our results suggest the possibility of clinical use of myo-inositol for augmentation of the mandibular growth in growing mandibular retrognathism patients in the future.

A systematic review on the outcome of distraction osteogenesis in TMJ ankylosis

Introduction

TMJ ankylosis (TMJa) management by arthroplasty alone fails to address the deformity and the compromised airway. Distraction osteogenesis (DO) can offer a pragmatic solution to TMJa. The aim of the study was to generate evidence towards the role of DO in TMJa, evaluate its efficiency and develop an algorithm for use of DO in TMJa.

Material and methods

The research question was formulated using the PICOS statement for reporting guidelines in systematic reviews, where the efficiency of DO was evaluated in terms of mouth opening, correction of facial deformity and asymmetry, airway correction, and its long term effects.

Results

1130 articles reported DO as a treatment modality for TMJ ankylosis, of which 32 prospective studies, 16 retrospective and 2 RCTs were included in the study. DO was used for mandibular distraction in 45 studies and for simultaneous maxillamandibular distraction in only five studies. An algorithm for use of DO in TMJa was developed.

Conclusion

Although DO has proven its application in TMJ ankylosis cases, its best use is for correction of obstructive sleep apnoea. Relapse causing loss of posterior ramal height is a concern after transport DO. Prearthroplastic DO appears to best correct mandibular deformity. A maxillomandibular deformity requires simultaneous maxillomandibular distraction. However, a metanalysis is still awaited for effectiveness of DO in TMJ ankylosis.

Nutritional supplementation with myo-inositol in growing mice specifically augments mandibular endochondral growth

INTRODUCTION

The purpose of this study was to examine growth-promoting effects of myo-inositol nutritional supplementation on the mandible in experimental animals.

METHODS

Mice were fed on diets that contained various concentration of myo-inositol for 3 to 12 weeks. The length of the mandible, maxilla, and femur were measured on μCT images. The mandible and tibia were examined histologically and immunohistochemically. The effects of myo-inositol on cell proliferation and chondrocytic differentiation were examined using ATDC5 cells.

RESULTS

Myo-inositol supplementation had no effects on body weight, length, and maxilla and femur lengths. However, the length of mandible and the thickness of the mandibular condylar cartilage (MCC) were increased by myo-inositol supplement. Microarray analysis revealed that Pik3cd was highly expressed in MCC as compared to that in the cartilage of the tibial growth plate, which was confirmed by real-time RT-PCR and immunohistochemistry. ATDC5 cells also highly expressed Pik3CD. Myoinositol induced increases in cell proliferation and chondrocytic differentiation in ATDC5 cells. The addition of a PIK3CD inhibitor blocked the induction of cell proliferation by myo-inositol in ATDC5 cells.

CONCLUSIONS

Nutritional supplementation with myo-inositol in growing mice augmented mandibular endochondral growth without any systemic effects. The specific promotion of mandibular growth by myoinositol is primarily dependent on the specific intensive expression of PIK3CD in the MCC.

Controlling the vector of distraction osteogenesis in the management of obstructive sleep apnea

Background:

Obstructive sleep apnea (OSA) in individuals with craniofacial anomalies can compromise airway and is a serious life-threatening condition. In many cases, tracheostomy is carried out as the treatment of choice. Distraction osteogenesis of the mandible as a treatment modality for OSA is very useful and may spare the need for tracheostomy or allow decannulation, yet controlling the vector of distraction is still a major challenge. We present a method for controlling the vector of distraction.

Materials and Methods:

Eight patients with severe respiratory distress secondary to a micrognathic mandible were treated by mandibular distraction osteogenesis using either external or internal devices. Temporary anchorage devices (TADs) and orthodontic elastics were used to control the vector of distraction. Cephalometric X-rays, computed tomography, and polysomnographic sleep studies were used to analyze the results.

Results:

A mean distraction of 22 mm using the internal devices and a mean of 30 mm using the external devices were achieved. Increase in the pharyngeal airway and hyoid bone advancement was also observed. Anterior-posterior advancement of the mandible was noted with no clockwise rotation. Most importantly, clinical improvement in symptoms of OSA, respiratory distress, and feeding was noted.

Conclusions:

We describe a method for controlling the vector of distraction used as a treatment for OSA. In these cases, TADs were used as an anchorage unit to control the vector of distraction. Our results show excellent clinical and radiographical results. TADs are a simple and nonexpensive method to control the vector of distraction.