1995, 10(4):201-204. DOI: 10.3871/j.1004-7220.1995.4.204.
Abstract:Hemorheology including blood viscosity,visco-elasticity and thixotropy has been studied in 71 patients with deep vein thrombosis in lower extremity.All the cases were confirmed by phlebography.The results showed high blood viscosity,decreased in red blood cell elasticity and increase value on each point of thixotropy-Hysteresis Loop in all.As compared with the control group,there is significant difference(p<0.01).However,the area of the Hysteresis Loop and the energy consumption have no remarkable difference(p>0.05)between the two groups.It reveals that the blood viscosity,red blood cell visco-elasticity and thixotropy take part in the formation of thrombosis.
1995, 10(4):205-208. DOI: 10.3871/j.1004-7220.1995.4.208.
Abstract:The tensile force acting on the suture line connecting a synthetic graft to a host artery in end-to-side anastomosis is shown to increase as the ratio of the graft-artery area,and has minimum value at 0.3 of the ratio of the flow rates.The angle of the end-to-side anastomosis is shown to have little effect on the suture line stress,but can not be negligated.Considering suture material and other factors,sufficient sutures per cm should be established.
1995, 10(4):209-213. DOI: 10.3871/j.1004-7220.1995.4.213.
Abstract:This paper discusses a new method by which the boundaries of the objects of the angiography can be located with recursive regularization filter and wavelet transform.The edges of the vessel can be accurately abstracted by the wavelet transform,after the noise and objects that fall below a scale of interest have been selectively removed by the filter under the regularization extent chosen.The result in this paper has explicitly show that it provides adequately accurate boundaries of the vessel that are of sufficient size in the width regularization extent.Comparing the method directly using wavelet transform and regularization filter respectively with the method which we proposed,the advantage of the method describing in this paper is complementary to the default that the wavelet transform badly reduces the correlative noise and add the multiresolution analysis which the regularization filter do not share.
1995, 10(4):214-219. DOI: 10.3871/j.1004-7220.1995.4.219.
Abstract:The measuring of the 3-D mechanical properties of the small artery is significant for the investigation and clinical diagnosis of vascular surgery and evaluation of treatment efficiency.In order to describe the performance of the artery blood vessel.On the basis of anisotropic and nonlinear behavior of the blood vessel,the author applied biomechanical principle to set up a three dimensional constitutive equation of small artery blood vessel.Going through the mechanical analysis,examination,and statistics,the accuracy and reliability of the data of small artery was defined.Thus,a dependable data was provided building up the model of parameters.
1995, 10(4):220-223. DOI: 10.3871/j.1004-7220.1995.4.223.
Abstract:With the analytic method of the construction-mechabism-function the authors have analysed the ball-like motion of intervertebral disc,and,especially,have calculate its motional status in biomechanics at the conjugative point,obtainning the characteristic values of ball-like conjugative motion of the supportive point of intervertebral disc,and,further,contraryly researching into the mechanism of intervertebal disc protrusion and its contrary characteristic value.
1995, 10(4):224-228. DOI: 10.3871/j.1004-7220.1995.4.228.
Abstract:Twenty simulant bones (polymethacrylate cylinders) were used in this experiment.The mid-shaft of each simulant bone was fixed with 316L stainless steel plate.Four of the 20 were served as control(no washer group) and the other 16 as experimental group(washer group).In the latter,different numbers and thickness of UHMWPE washers were inserted in between the screw-hole walls and the screws.The longitudinal loading test was performed immediately,and at 4,8,12and16 weeks after plate fixation,respectively.The strain of the surface between 2 screw holes in the plate and on the mid-shaft of the simulant bones apposite the plate was measured so as to calculate the stress shielding rate of plate on bone.The results demonstrate that the stress shielding rate of plate on bone would gradually decrease in the washer group and keep constant in no washer group after fixation.Ten weeks later,there was significant difference of the stress shielding rate between the two groups.The resutls also show that if the thickness of the washers remain unchanged,the greater the number,the more obvious the reduction of the stress shielding rate at the later stage.It is suggested that the stress shielding rate of the plate on bone in the washer group is closely related to the number of washers.
1995, 10(4):229-234. DOI: 10.3871/j.1004-7220.1995.4.234.
Abstract:Loading on imitative tibiofemoral joint of a flexed knee in 0°,10°,20°and 30°,which is made of photoelastic material. The result shows that the tibiofemoral touching area of internal condyle is larger than external condyle, the stress distrbution of external condyle is stronger than internal condyle, the strongest stress distribution is on the area of touching centre. With the angle of flexed knee joint goes larger, (1) the centre point moves backward, within 30°,the slide rate of internal side is 40.23%, external side is 45.92%;(2)two centre points of tibial plateau move medially,the distance between the centre points is enlarged; (3) tibiofemoral touching area decreases; (4) the peak value of stress increases, the increasing rate is far higher than decreaseing rate in area. The result of the experiment points out that for correcting knee deformity, recovering the normal tibiofemoral para-position and stress distribution should be paid more attention.
1995, 10(4):235-237. DOI: 10.3871/j.1004-7220.1995.4.237.
Abstract:Artificial joint replacement is a feasible approach to serious arthritic diseases. The 3D reconstruction for femur provides scientific basis for the prostheses optimal design. Development of Computed Tomograph makes it possible to obtain the geometry shapes of bone cross sections nondestructively. When the cross sections are arranged in sequence along the bone axis, the 3D image of bone can be developed. By taking the femur for example this paper presents a new 3D reconstruction process of human bone systemly including CT image processing, outline points screening, 3D mesh surface building and image rendering.
1995, 10(4):238-244. DOI: 10.3871/j.1004-7220.1995.4.244.
Abstract:This paper investigates the fatigue fracture of tibia that often occurs in soldiers, as well as in dancers and athletes. The data of ground reaction force(GRF) of soldiers were measured using a force platform in three common gaits, the marching, parading and running. The stress distribution in tibia under these GRF's were analyzed with a FE model. Then the fatigue life of fresh human tibia specimens were tested under the corresponding maximum stress by compressive fatigue test.Results show that the GRF is the smallest in quick marching, the next in parade step and the largest in running. e. g. the maximum vertical force are 1391. 6N、1156. 4N and 744. 8N in running,parading, and marching steps, respectively. The stress distribution under the GRF is not uniform in the tibia. The maximum stresses occur at the position 1/3 tibia length from the upper end,where the tibia fracture often ocurs in clinic. The maximum stresses are 110MPa and 115MPa in the parade step and running respectively. The fatigue lifes of tibia specimens are 793, 927,2467 and 13425 under the compressive stress of 100MPa, 90MPa, 70MPa and 50MPa, respectively. This means that the fracture in tibia are mostly like stress fractures, the larger the stress, the higher the incidence of stress fracture.
1995, 10(4):245-248. DOI: 10.3871/j.1004-7220.1995.4.248.
Abstract:An new type of artificial vertebral body was designed for the surgical treatment of vertebral replacement.It was mainly composed of a grooving spring is located in the middle of the artificial vertebral body and the platforms are fixed to the upper and lower ends of the spring by forth-and-back hand thread. Through turning the spring, the height of the artificial vertebral body could be adjusted. This artificial vertebral body possesses the movable function of axial compression, the flexion, extension and lateral bending.
1995, 10(4):249-252. DOI: 10.3871/j.1004-7220.1995.4.252.
Abstract:According to the concept of hybirds of simple, clamp, and ring fixators,we modified the AO/ASIF tubular device into a modified AO/ASIF fixator I. The biomechanical studies for axial compression, tension, anterior-posterior bending, and medial-lateral bending showed that the four characteristics of the modified AO/ASIF fixator I are significantly superior to the Hoffmann and AO/ASIF devices.Between July 1992 and December 1993, 31 consecutive tibial fractures were treated using the modified AO/ASIF fixator I. Early follow-up of 11-17 months showed that all fracture healed. The time of fixator removal was 16-32 weeks, averaged 22. 2weeks. In treatment of segmental fractures, the modified AO/ASIF fixator I gave more improved results over others among simplicity of frame,simplification of operation, and relibility of mechanical quality.