Design And Manufacture Intra-support Fracture Fixator Of Hook Type For The Zygomatic Arch Through Intraoral Incision

Part I : Measurement The Anatomic Data Of The Zygomatic Arch.Objective: To design a kind of internal fixation instrument aiming at zygomatic arch fracture, we measured the anatomic data of the zygomatic arch.Methods: The zygomatic arches of 107 dry skulls(56 males, 51 females) were measured with sliding gauge in our study, certain datas such as the arch chord length, depth, thickness,width were included. We analysed the datas with statistically methods to assure that whether the datas have left-right difference or sex difference or not.Results: 1.The anatomic datas of the male or female zygomatic arch of right and left have no statistically difference(P>0.05).2.The arch chord length, depth, thickness,width of the male zygomatic arch are higher than those of female(P<0.05).Conclusions: 1.We measured the arch chord length, depth, thickness, width of the zygomatic arch to provide the anatomic basis for the design-manufacture of intra-support fracture flxator of hook type for the zygomatic arch.2. The lower edge of the zygomatic arch could be exposured clearly through intraoral incision. But its thickness does not favor rigid internal fixation.Part II: Design and Manufacture Intra-support Fracture Fixator of Hook Type for the Zygomatic Arch through Intraoral IncisionObjective: To design and manufacture a new type of fracture fixator of the zygomatic arch through intraoral incision, isolated fractures of the zygomatic arch fixed by intra-support fracture fixator of hook type for the zygomatic arch were tested for the sake of understanding its biomechanical function.Methods: 1. According to the anatomic data and the biomechanical capability of the zygomatic arch, we designed and manufactured a new type of fracture fixator of the zygomatic arch through intraoral incision.2. In the experiment, 10 pieces of zygomatic arches were used and two point fracture model were made. These zygomatic arches fracture model were marked serial number in random and divided into four groups according to experiment sequence: anatomic realignment without any fixation( I group); anatomic realignment and fixed with miniplates (II group); anatomic realignment and fixed with intra-support fracture fixator of hook type for the zygomatic arch, the end of the hook beyond the middle of the zygomatic arch (IIIa group) , the end of the hook leave the middle of the zygomatic arch (IIIb group) .3. The compress test are performed on the four groups fracture model. The extreme load were registered and compared between IIIa group, IIIb group and I group, II group with statistically methods. The loads corresponding to the displacement of 0.5mm,1.0mm,1.5 mm and 2.0 mm were read from the load-displacement chart in IIIa group, IIIb group and II group and were analysed with statistically methods.Results: 1. The extreme loads of IIIa group and IIIb group were higher than that of I group(P<0.05). The extreme loads of IIIa group and IIIb group were lower than that of II group(P<0.05).The extreme loads of IIIa group and IIIb group have no statistically difference(P>0.05).2. The loads corresponding to the displacement of 0.5mm, 1.0mm, 1.5 mm and 2.0 mm of II group are higher than those of IIIa group and IIIb group(P < 0.05).The loads corresponded to the displacement of 0.5mm, 1.0mm, 1.5 mm and 2.0 mm of IIIa group and IIIb group have no statistically difference(P>0.05).Conclusions: 1. Intra-support fracture fixator of hook type for the zygomatic arch could be bended and cut at will and could be used to fix fractures of the zygomatic arch through intraoral incision conveniently.2. The bearing capacity and the anti-bending capacity of the zygomatic-arch- miniplates are better than those of the zygomatic-arch-fixator. But compared with the realignment zygomatic arch without any fixation, the zygomatic-arch- fixator has better bearing capacity.3. That whether the end of the hook beyond the middle of the zygomatic arch or not has no obviously influence on the bearing capacity and the anti-bending capacity of the zygomatic-arch- fixator.