| Objective:To investigate the effect of digital 3D printing in the operation of zygomatic maxillary complex(Zygomatic-Maxillar Complex,ZMC)fractures and the feasibility of evaluating symmetry with multiple facial markers.Methods:Forty-five patients with unilateral zygomatic maxillary complex(ZMC)fractures admitted to Yangzhou University Affiliated Hospital from September 2019 to April 2022 were included.According to whether the patients used digital 3D printing technology,they were divided into experimental group(n = 22)and control group(n =23).The experimental group according to the shape of healthy side ZMC microreplaced the affected side with the software in 3D images before operation.3D printer(3Dsystems Company,USA)was used to print 3D skull model(Shanghai Yilun 3D Design Co.,Ltd.),analyzed the fracture model before the operation,evaluated and designed the surgical plan,pre-prepared the intraoperative fracture repair and fixation titanium plate(mesh),and guided the model and repair titanium plate.In the control group,the fracture was reduced and fixed according to the experience of the operator.The degree of mouth opening,the amount of bleeding during operation and the time of operation were recorded,all patients were followed up 1 week and 3 months after operation,the spiral CT was reexamined one week after operation,the virtual three-dimensional coordinate system was established by using the CT images before and after operation,according to the facial symmetry zygomatic protruding starting point(ME)、 the intersection point between the lateral edge of zygomatic frontalis and the superior edge of temporal process(J)、the most prominent point above point J(SJ)、the outermost point of zygomatic arch(Z)and the lowest point of suborbital margin(O)were selected.The vertical distance between each marking point and the coordinate axis was obtained,and the facial asymmetry index(Asymmetry index,AI)was calculated,and the AI value of the same marker point before and after operation was obtained to evaluate the improvement of symmetry of the same point before and after operation.Results: 1 、 There were significant differences in AI differences between the experimental group and the control group at MZ point,J point,SJ point and Z point before and after operation(all P<0.05),but there was no significant difference in AI difference between the two groups before and after operation(P=0.05).2、The degree of mouth opening was 2.72 ±0.79 cm,slightly restricted 13.64% and moderately restricted 22.73% before operation;The degree of mouth opening was 3.59±0.29 cm,there were no patients with limited mouth opening after operation in the experimental group.The degree of mouth opening was 2.96 ±0.60 cm,with mild restriction 8.70% and moderate restriction 13.04% before operation;The degree of mouth opening was 3.53 ±0.24 cm with mild restriction 4.35% and no moderate restriction after operation in the control group.There was no significant difference between the two groups(P>0.05),the mouth opening degree of the two groups returned to normal after operation,but there was no significant difference between the two groups(P > 0.05).3、The operation time was 158.41 ±50.20 min in the experimental group and 175.87±37.65 min in the control group.There was no significant difference in the operation time between the two groups.The intraoperative blood loss was 173.64 ±62.30 ml in the experimental group and 212.61±52.68 ml in the control group,the amount of intraoperative blood loss in the experimental group was significantly lower than that in the control group(P < 0.05).Conclusion: The application of digital 3D printing technology to assist ZMC fracture surgery can effectively improve the symmetry of facial appearance,and do not increase the length of operation,which is a more accurate and feasible method.It is simple and practical to evaluate facial symmetry with multiple markers. |
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