Sacroiliac Joint Fractures Treated By Posterior Sacroiliac Screw Dislocation Of Biomechanics Of Observation

Objective:Sacroiliac joint fracture dislocation is a common severe pelvic fracture damage, often with pubic symphysis separation or pubic bone fracture, serious damage to the stability of the pelvic ring before and after.There are scholars with reconstruction plate fixation ring before, after the tension screw ring of sacroiliac joint method of treatment, can restore the stability of pelvis.Especially the tension screw has satisfied, small trauma, and low risk of infection.But using one or two pieces of screw fixation, there were differences in clinical work.This study attempts to look for pieces of screw 1 and 2 pieces of screw sacroiliac joint mechanical stability, provide a reference for clinical treatment.Method:1. Preparation of sample Selection four of adult antiseptic body, Since 4,5, a third lumbar border and double leg bodies will cross sectional. Excluding attached to the pelvis and femur of fat, muscle and other soft tissue, Keep complete bilateral sacroiliac joints, bilateral hip, double lateral sacral spine ligaments, bilateral sacral nodules ligaments.there are four pelvic specimen.2.Preparation of the experimental model According to the experimental design, the preparation of sacroiliac joint dislocation, pubic symphysis separation model. All specimens model pubic symphysis line 6 hole reconstruction plate fixation, Then according to the experiment with a first order sacroiliac sacroiliac joint tensile screws, made a set of fixed screw. After biomechanical testing, Add a sacroiliac sacroiliac joint tensile screws, Made from two fixed set screw.3. Experiment method. Will correct fixed Yu Lixue instrument experiment model, through the waist 5 vertebral fracture dislocation model for the axial compression test. Biomechanics of instrument to automatically generate related data, and store analysis by computer。At the same time corresponding processing data records (including load-displacement value and the axial stiffness) Pelvic specimen of sacroiliac joint separation of vertical displacement available electronic digital display micrometer to measure。4.Statistical Analysis Application SPSS 17.0 statistical software for statistical analysis of three sets of data for each group of data such as displacement and axial stiffness, Comparison between two fixed methods using paired t test, test of significance is P< 0.05 for the difference was statistically significant.Results:Within 0-1000 n pressure, under the same loading a sacroiliac screw fixation group of sacroiliac joint vertical displacement, pelvic overall sinking displacement is greater than 2 pieces of sacroiliac screw group (P> 0.05), pelvic axial stiffness is less than 2 pieces of screw group (P> 0.05), there was no statistical difference in 0-1000 n pressure range, under the same loading a sacroiliac screw fixation group of sacroiliac joint vertical displacement, pelvic overall sinking displacement is greater than 2 pieces of sacroiliac screw group (P>0.05), pelvic axial stiffness is less than 2 pieces of screw group (P>0.05), there was no statistically significant difference.Conclusion:The experiment research shows that the simulated physiological load cases, via a sacroiliac screw and two pins fixed pelvic stability of sacroiliac joints, there is no obvious difference.Clinical instability pelvic fractures treated with a screw can be obtained the preliminary stability.