The Evaluation Of Sacral Vestibule And Clinical Value On Iliosacral Screws Fixation Of Pelvic Injury

ObjectiveTo measure the anatomic parameters of three-dimensional space on sacral vestibule, and investigate their clinical value on iliosacral screws fixation of pelvic injury.Make assessment of the degree on vestibular available space decrease with different sacral fracture displacement,and deduce the least clinical accepted level of the fracture displacement which can operative safely.Methods1.Seventy-four sacrum specimens with normal anatomic character were evaluated precisely with their both sides' vestibules,the parameters were recorded.2.Thirty-six of the specimens were accepted three-dimensional CT reconstructions, and measure the parameters of vestibules.3.Analyzed the parameters obtained with image evaluation and the ones obtained with actual measurement,to find whether there were difference between two groups.4.Analyzed the parameters of the sacral vestibules precisely,obtained its shape configurations and size characters,and investigate their clinical values.5.Make the simulated model of sacral vestibules in computer with 3D software. Simulated the different degrees of sacrum fracture displacement,and measure the intact' sizes of two fracture parts.Analyzed the parameters and deduce the least clinical accepted level of the fracture displacement which can implant the iliosacral screws safely.Results1.With statistical analysis,it proved that there was not significant difference between the parameters actual measured on the specimens and the ones obtained with image evaluation.2.The mean vestibular width(VD) was 24.79±2.91mm,the mean vestibular height(VH) was 20.19±3.03mm,and the mean vestibular size(VS) was 395.23±85.11mm~2.There were significant difference between the parameters of male and the ones of female except VH.The parameters of different sides in same sex had not significant differences. 3.Through analysis of simulated experiment data,we can deduce that the safe implant standard of the iliosacral screw was 5mm with superior-inferior displacement and 10mm with anterior-posterior displacement.Conclusions1.The anatomic parameters of sacral vestibule for Chinese people are less than foreigners,with area 1/4-1/3 less.Therefore the requirement must be more rigid for operation and internal fixation implant standard.2.The anatomic parameters of female were much less than the ones of male and close to the least standard of iliosacral screws implant.Therefore the female patients who need accept iliosacal screws operation must have the CT scans preoperatively,measure the parameters of sacral vestibule,and make the operation plan in detail.The requirement of operation technology need much more rigid.3.All the fractures with displacement more than 5mm in superior-inferior and 10mm in anterior-posterior must have reduction before the iliosacral screws being implanted.It was also advised to have reduction to ensure the fracture fixation stability when the displacement was less than 5mm.