A Study Of Zygomatic Three-dimensional (3D) CT Based Cephalometric Analysis And The Basic And Clinical Application Research Of The Malar Augmentation With L-shaped Zygomatic Osteotomy

Objective The cheekbone in a prominent position of face played an important role in facial appearance.But there was no useful information about the 3D CT based cephalometric analysis of the cheekbone in orientals for zygomatic plasty.Through 3D CT based cephalometric analysis,to obtain the aesthetics of 3D characteristics of the zygoma.According to these parameters,the diagnosis and plastic surgery of zygomatic deformities could be carried out more precisely.Based on this,the basic and clinical application research of the L-shaped zygomatic osteotomy augmentation with coral graft was carried out,to explore the biomechanical changes,the absorption of coral.osteogenic process,and a new effective method for correction of malar-zygomatic deficiency.Zygomatic 3D CT based cephalometric analysisMethod:58 prominent zygomatic female patients who underwent reduction malarplasty were randomly selected.And 10 normal female beauties were selected by plastic experts.The cephalometric points represent the features of middle and upper face,and the characteristics of the zygomatic structure in 3D CT reconstruction images were selected.Among them,24 parameters were measured.The results of the two groups were statistically analyzed using independent samples-t test. Results::5 parameters had statistical significance(P＜0.05):zy-zy,zp-zp, Or-zb,front face width index,the zygoma/forehead index.Thickness of 1/ 2 height zygomatic body close to the maxillary(Zt)=11.55±0.88mm in prominent zygomatic female patients;Thickness of zygomatic arch(Wz) =6.15+0.55mm。Animal experiments of L-shaped zygomatic osteotomy augmentation with of coral graftMethods:21 healthy adult goats were randomly divided into 3 groups of 7. A(negative control group):the osteotomy gap was stabilized with a titanium plate.B group(positive control group):the osteotomy gap was stabilized with interposed autologous bone block.C group(experimental group): purified and sterilized coral graft was inserted into the osteotomy gap. Goats were euthanized 1,3,6 and 12 months after operation.By histology, X-ray and CT imaging,biomechanics studies,we drew the following conclusions:(1)The pore's of the Porites that we used average diameter was 503.86±112.43μm.Application of SEM with EDX in Material Analysis, Porites's main component was calcium carbonate(98.65%).Trace element contents were Na0.53%,Sr0.32%,Mg0.28%,S0.22%.(2)3 to 6 months after implantation,the absorption of coral reached a peak.Total absorption rate of coral was about 16.9%12 months after operation.(3)Coral had been partly absorbed in 1 month,but it still had been seen 12 months after operation in the X-ray films.(4)6 months post the zygomatic osteotomy operation, corals and autologous bone implantation had no differences in biomechanical properties.But both of these two groups did not reach the normal zygomatic mechanics level.(5)6 to 12 months after coral implantation,histological repair were achieved.Clinical application research of the malar augmentation with L-shaped zygomatic osteotomy36 patients received malar augmentation with L-shaped zygomatic osteotomy through an intraoral incision.The external rotation was stabilized with interposed coral graft in 16 cases,bone graft in 20 cases.During 3 months to 6 years,28 cases were followed up.Among the 28 cases,two cases(7%) complaint upper lip numbness.There was no complication such as implant infection,hematomas,maxillary sinus and so on.The post surgery results were: perfect for 12 patients(42.9%),good for 10 cases(35.7%),acceptable for 5 cases(17.9%),poor for 1 patients(3.6%).The process and the height of the zygomatic body,as well as the width of zygomatic arch had been improved.At the same time in the process of clinical application research,to resolve the problem that deep operative area being seen unclearly caused by the blood, a special zygomatic retractor was invented by my mentor and me,and applied for a utility model patent. Conclusion Prominent cheekbone diagnosis may refer to these five parameters:zy-zy,zp-zp,Or-zb,front face width index,the zygoma/forehead index.Thickness of 1/2 height zygomatic body close to the maxillary (Zt)=11.55±0.88mm in prominent zygomatic female patients;Thickness of zygomatic arch(Wz)=6.15±0.55mm。Malar augmentation with L-shaped zygomatic osteotomy through an intraoral incision could increase the process and the height of the zygomatic body, as well as the width of zygomatic arch.Animal experiments also confirmed that,6 to 12 months after coral grafts being inserted into the expansion gap,histological repair were achieved.Total absorption rate of coral was about 16.9%.L-shaped zygomatic osteotomy augmentation through an intraoral incision with coral graft is a good choice for correction of malar-zygomatic deficiency.