The Three-dimensional Reconstruction And Analysis Of The Cervical Vertebrae Posture In Patients With Mandibular Developmental Asymmetry

Developmental lateral jaw deformity (DLJD) is a common kind of jaw deformity in clinic. Patients suffer from not only craniofacial paramorphia but also oral dysfunction. Additionally, recent studies have found that DLJD was often accompanied by abnormal cervical curve and pain in head-neck, shoulder and back muscles, which are similar to cervical spine disorder (CSD).Up to now, it is not clear that whether DLJD could lead to CSD and by what way it does. Therefore, studies of facial morphology, cervical spine curve and also oral clinical examination were preformed to research the relationship between these two kinds of disease. The detailed statistical relationship between head posture, cervical vertebrae and facial morphology was demonstrated by Solow and Tallgren, who proposed a hypothesis to account for the association between them, so called"soft tissue stretching". At present, there is a lot of arguments on the relationship between head posture, cervical vertebrae ,and facial morphology .The detailed statistical relationship between head posture and facies cranii was researched by the foreign investigators in the 90 times of the 20th century, and they found preliminarily the relationship between cervical vertebrae and mandibular asymmetry ,but there was some difference between their conclusions because of their different control facts and methods. The relationship between cervical vertebrae , head posture and facial morphology was researched by the our investigators in the 90 times of the 20 th century, but the reports about the feature of cervical vertebrae in patients with mandibular asymmetry are based on radiographic research, which does not support correctly the diagnosis and treatment of change of cervical vertebrae in patient with mandibular asymmetry, because of graphic distortion with the result of anatomic structure's overlap and amplification of image on radiography.Based on the above research, we apply with Spiral Computed.Tomography and three-dimensional reconstruction technology to study the characterization of change of cervical vertebrae in patient with mandibular asymmetry. At present, the method that we used is not reported. The 20 cases of mandibular developmental asymmetry belong to experimental group and the other cases in 20 people with normal occlusion are control group. There are two aspects in this research.1. The three dimensional reconstruction of the facial and cervical vertebrae posture in patients with mandibular developmental asymmetry.The sample consists of 20 adolescent patients, including 10 men and 10 women respectively. There are 12 cases of mandibular right lateral deformity and 8 cases in left hand side. The CT images of cervical vertebrae and facies cranii are processed by HP Workstation xw8000, as well as recording the result Dicom standard. We apply with Mimics8.13 to obtain dates of image, and reconstruct the three-dimensional model. The 29 collected landmark are analyzed by correlation analysis and regression analysis, from which we can obtain the coordinate value of each landmark and the coherence of location. Conclusion: We propose that the location of landmarks on three-dimensional reconstructive image in the surface of bone tissue is the standard of three-dimensional reconstruction in the cervical vertebrae of the patient with mandibula asymmetry.2. The three-dimensional analysis of the cervical vertebrae posture in patients with mandibular developmental asymmetry. The sample consists of 20 adult patients with mandibular lateral deviation. 20 adult with normal occlusion were as the control. We scan cervical vertebrae and facies cranii by CT. After applying with three dimensional reconstruction, we observe the bone structure of facial and cervical vertebrae, as well as analyzing the facial morphology and curvature of cervical vertebrae. We try to find out the characterization of change of cervical vertebrae in patient with mandibular rilateral deformity. The research shows that the cervical vertebrae posture of the experimental group displays significant asymmetries in all three dimensions with both linear measurements and angular measurements. The results about coronal plane indicate that the distance between each TP of the non-shafted side and the MS plane is bigger than the distance between each TP of the shafted side and the MS plane, especially in the middle region of the cervical vertebrae(C3,C4,C5), the difference between non-shafted side and shafted side has statistically significance, which means that the cervical vertebrae inclines to the non-shafted side and bends like a bow in anterior-posterior view. The results about MS plane show that the angle formed by CP plane and FH plane is smaller than the control group, which means that the upper cervical vertebrae inclines and bends forward much more comparing with the control group. OPT-CVT angle is bigger in experimental group than in control group, which means that the mandibular deviation patients'cervical vertebrae bends more than normal people. The results about transverse plane show that the angle formed by the line connecting both TPs of each vertebrae and MS plane increases from lower vertebrae to upper vertebrae. The difference of the angle formed by C2 and C3 between experimental group and control group has statistically significance, which means that the cervical vertebrae of the mandibular deviation patients rotates around the Y axis in the opposite direction the chin did. Conclusion The cervical vertebrae posture among patients changes in all three directions and should be paid more attention to while we treat the mandibular deviation.