| Objective:1. To establish a three-dimensional measurement method suitable for bone tissues and soft tissues in hemifacial microsomia cases. Three-dimensional data from CT imageology and facial scanning were used to conduct quantitative evaluation of the deformed bone tissues and soft tissues in the craniofacial region, and to analyze the morphological characteristics of the facial asymmetry deformity.2. To discuss the combined procedure of distraction osteogenesis with sagittal split ramus osteonomy (SSRO) to treat hemifacial microsomia and its clinical effect with the aid of digital technology.3. To use the three-dimensional measurement method to measure and analyze changes of bone tissues and soft tissues before and after the modified distraction osteogenesis treatment for hemifacial microsomia, and evaluate the result of operation quantitatively.Methods:Successive cases of 10 patients with hemifacial microsomia treated at the Department of Maxillofacial Plastic Surgery, Plastic Surgery Hospital, Chinese Academy of Medical Sciences from June 2013 to October 2015 were selected for this study.1. After the the CT data and three-dimensional facial scanning data of hemifacial microsomia patients were input into MIMCS to establish the three-dimensional coordinate system for measuring bone tissues and soft tissues, the anatomical landmarks would be marked to conduct accurate quantitative analysis of both side of face. Further, the morphological characteristics of facial asymmetry deformity would be discussed and the method for preoperative evaluation would be assured.2. Before the surgery, three-dimensional CT data were used to reconstruct bone tissues models. We marked the locations of inferior alveolar neurovascular bundle and dental germs, on the basis of which an accurate operation design for osteotomy would be worked out. The distances and directions of distraction according to the asymmetry of the affected and unaffected sides will also be planned. The distraction osteogenesis combined with sagittal split ramus osteonomy (SSRO) would be performed in the operation. Afterwards, the postoperatively rapid traction would be applied to lengthen the mandible and improve facial asymmetry.3. We used the three-dimensional measurement method to conduct preoperative and postoperative comparative analysis of hemifacial microsomia patients, and calculated the changes of marked points as well as the important distances such as the length of mandibular ramus before and after the surgery. We quantitatively analyzed the improvement of asymmetry of bone tissues and soft tissues in hemifacial microsomia patients who have undergone modified distraction osteogenesis.Results:1. A three-dimensional measurement method was established to conduct analysis on the 10 cases of facial soft tissues deformity and the morphological characteristics of soft tissues in hemifacial microsomia were discovered.2. Modified distraction osteogenesis based on digital technology was applied in the operation of 10 patients with hemifacial microsomia and no serious complications were detected. Important vessels, nerves and dental germ structures were effectively protected, the facial asymmetry was significantly improved and the plane of occlusion became horizontal. The effect was satisfactory.3. After the operations, the length of mandibular ramus of the affected side rose from 35.90+3.85 mm to 44.85 ± 5.05 mm, the thickness of mandibular ramus of the affected side rose from 8.29 ± 1.00 mm to 10.08 ± 1.64 mm. The asymmetric rate of bilateral mandibular ramus reduced from 30.30%±4.80% to 13.27%±5.60%. The distance from chin point to facial midline decreased from 13.19±3.52 mm to 5.61 ± 2.67 mm. The distance from angulus oris to outer canthus rose from 62.93±5.61 mm to 65.92 ± 5.84 mm. The distance from angulus oris to tragus rose from 77.58 ± 9.34 mm to 82.22± 10.71 mm. The results have statistical significance. To summarize, the asymmetry of facial bone tissues and soft tissues was significantly improved.Conclusion:1. The three-dimensional measurement is an accurate and reliable method to analyze the symmetry of hemifacial microsomia and develop a relevant operation plan. This research discusses the three-dimensional method for measuring the asymmetry deformity in soft tissues, which also applies to other researches in craniofacial anomalies and aethestics, thus advanced study should be carried out in this direction. The deformity of facial soft tissues is dimensional asymmetry. The condition of the lower face is more serious than that of the upper face.2. The combined application of distraction osteogenesis with sagittal split ramus osteonomy (SSRO) can speed up the distraction, shorten the period of treatment and reduce the risk of complications, thus treating the asymmetry deformity of hemifacial microsomia with great effect.3. Quantitative evaluation of the preoperative and postoperative changes proofs that the treatment effect of modified distraction osteogenesis is positive and reliable. The three-dimensional measurement can be used to evaluate the treatment effect of hemifacial microsomia or other craniofacial anomalies. This method has wide adaptability and high practicability, and it should be promoted for clinical use. |
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