| There is no report about osteotomy of the outer mandibular cortex combined with coral implantation for treatment of hemifacial microsomia at home and abroad. This article illustrates our study about osteotomy of the outer mandibular cortex combined with coral implantation in the basic and clinic area, and reports the results of our research.Animal experiment: 10 miniature pigs at age 8-12months were selected as the experimental animals which were divided into 2 groups randomly: group A and group B. In group A, the outer cortex of mandibular body and angle was split in one side and coral (thickness: 0.5cm) was implanted into the gap between the outer and inner cortex of mandible, with the other side as control. In group B, two kinds of coral (thickness: 0.5cm and 1cm) was implanted into the gaps with the same methods separately. Computer tomography (CT) was applied preoperatively, immediately after operation and 6 months after operation. 2 pigs were selected randomly in each group and were killed 12 weeks after coral implantation. Specimen was harvested from implantation site of mandible, and then histological study (HE stain, scanning electron microscopy) was performed. The rest animals were killed 6 months after operation. Gross inspection of the mandible was performed at that time including the condition of the coral. The bone of mandibular angle region was collected bilaterally in 6 pigs and sent for biomechanical test. Histological studies (HE stain, scanning electron microscopy, Azan Mallory special stain) were performed in the other 2 pigs. The results showed:â‘ After the osteotomy of the outer mandibular cortex combine with coral implantation, mandibular body get thicker. There was no obvious difference between experimental side and normal side in the histology area and no obvious impact on the maximum stress of mandible. So osteotomy of the outer mandibular cortex combine with coral implantation is a suitable method for the expansion of mandible.â‘¡Gross inspection showed that the wound in the experimental side of mandible had almost been healed, and depression was seen at the inferior border of mandible. Soft tissue had grown into the coral, especially when the thickness of coral is 1cm. Bone tubercle can be found at angle area.Clinical research: There were 11 patients of hemifacial microsomia treated with method above. Using computer tomography (CT) dissection technique, variables were observed and analyzed including the thickness of mandible preoperatively, immediately after operation, 6 months after operation; regeneration at 6 months after operation compared with immediate after operation; direct sight of the appearance of patient. The results showed:â‘ thickness of the mandible immediately after operation became 5. 80mm thicker than that preoperatively, and thickness of the mandible 6 months after operation became 4.81m thicker than that preoperatively;â‘¡Asymmetry of lower 1/3 face has been improved obviously because of the accrescence in thickness of the mandible in corresponding side after coral implantation.Conclusion: New bone regeneration in the gap and histological structure can almost repair after osteotomy of the outer mandibular cortex combined with coral implantation. Mandible got thicker obviously. Although soft tissue grew into the coral, there was no obvious impact on the maximum stress of mandible. Bone resorption happens after coral implantaion, but the thickness of mandible immediately after operation has no significant difference from 6 months after operation. Conclusion supports the clinical application of osteotomy of the outer mandibular cortex combined with coral implantation for the treatment of hemifacial microsomia. Quantization of bone resorption rate can guide its clinical application. The inconsistence of bone resorption rate between animal experiment and clinic research should be studied further with the improvement of experiment condition and augmentation of sample size.
|
PDF Full Text Request