Experimental Study Of Bone Cement Infusion In Different Proportions According To Balloon Volume In PKP

Objective:1.Using EDTA-Na2on adult swine vertebral decalcifiedprocessing to simulate a vertebral osteoporosis, and in general, pathology, DRobservation and the measurement of bone mineral density (BMD), vertebralbody strength and stiffness of vertical compression test, observation in theshort term to produce osteoporosis vertebral model results, to explore a rapid,effective and reliable in vitro preparation of vertebral osteoporosisbiomechanical model of the method;2.Using EDTA-Na2preparedosteoporosis model, in the universal material testing machine verticalcompression vertebral body compression fractures underwent model,kyphoplasty (PKP) for biomechanical analysis, according to the differentratio of balloon volume of bone cement perfusion after vertebral biomechanicschanges, to provide reference data for clinical treatment.Methods:1.Six fresh swine spine, thoracic lumbar segment to be chosenevery with section6, A total of36vertebral body, measuring the fanteriorflange height,10%of formaldehyde to soak for24hours, one side eachvertebral body through pedicle with diameter of2.0gram holing needle to thevertebral body near the center, randomly divided into4groups, each group ofnine vertebral bodies,4kinds of processing methods: as control group A, don’tdo processing, group B to A tendency for0.595mol/L EDTA-Na2solutionfor10days, group C decalcified15days, group D decalcified20days,decalcified group every day to50ml syringes by pedicle screw hole injectionEDTA-Na2decalcified fluid,2times A day, each time1minute. Groups ofrandomly selected from a vertebral body, sagittal cut open line generallyobserved, at the same time take nail, made a small amount of cancellous bonebiopsy line around the microscopic observation. Each group of randomlyselected from the second quarter vertebral observation line of DR. Detection of each vertebral body bone mineral density (BMD). Respectively eachvertebral body on the universal material testing machine, to5mm/min loadingrate of vertical loading, until the specimen to yield25%, get a load-deformation curve, the maximum load as the compression strength (Fmax),the load-deformation curve of the slope as the compressive stiffness.Observations with the extension of decalcified time, vertebral BMD, thechange of vertebral body compression strength and stiffness;2.Six fresh swinespine, thoracic lumbar segment to be chosen every with section6, A total of36vertebral body,10%formaldehyde to soak for24hours, one side eachvertebral body through pedicle with diameter of2.0gram holing needle to thevertebral body near the center, with EDTA-Na2decalcified20days,preparation good osteoporosis vertebral bodies were randomly divided into A,B, C, D four groups, each group of nine vertebral bodies, testing eachvertebral body bone mineral density (BMD), and so on the universal materialtesting machine, to5mm/min loading rate of vertical loading, until thespecimen to yield25%, record the maximum compression strength andcompression stiffness and compressed vertebral bodies before and afterfanterior flange height. After each group separately PMMA perfusion vertebralbody shaping, according to the different proportion of balloon expansionvolume infusion PMMA, groups A, B, C, D PMMA perfusion with balloonexpansion volume ratio respectively0.8:1;1:1;1.5:1;2:1. After the recordvolume and pressure of the balloon, balloon expansion forming fanteriorflange height and Numbers of vertebral body bone cement leakage. After thesecond load test, according to the method of initial compression vertebral body,record biggest vertebral body compression strength and stiffness at this time.Results:1.Gross specimen observation: group B, C, D pedicle nail holesin order to expand, the decalcified fluid invasion scope, in turn, increases;Tissue section showed: B, C, D group of trabecular bone tapering, widerspacing; DR test shows: compared with group A, B, C, D group of vertebralbone mineral density decreases, bone loss, particularly group D; B, C, D group,BMD, vertebral body compression strength and stiffness were lower than group A, and in turn reduce the trend, comparison between groups wasstatistically significant (P <0.01);2.Four groups before PKP of anterior heightof vertebral body, vertebral compression strength and compression stiffnesswere not statistically significant (P>0.05); Each group before and after PKP,vertebral maximum compressive strength and stiffness compared withstatistical significance (P<0.01); After PKP, A,B group between vertebralcompression strength and stiffness is not statistically significant (P>0.05); A,B and C, D between vertebral compression strength and stiffness comparedwith statistical significance (P<0.01); After PKP four groups betweenrestoration of vertebral height values were not significant (P>0.05); A, Bbone cement leakage rate was0, C, D bone cement leakage rate were:22.22%,44.44%.Conclusion:1. The bone mineral density (BMD), vertebral body compression strengthand stiffness can reflect the degree of vertebral osteoporosis and vertebralbody biomechanical performance, BMD can provide help for the clinicaldiagnosis of osteoporotic bone disease;2. The application of EDTA-Na2decalcified method can be established in arelatively short time for the biomechanical research of osteoporoticvertebral body model;3. According to the balloon in PKP holds the expansion volume0.8-1timesthat of the infusion of bone cement can effectively restore vertebral bodyosteoporotic compression fractures of biomechanical properties, and canreduce the leakage of bone cement;4. According to the balloon in PKP holds the expansion volume0.8-1timesthat of the infusion of bone cement can partly restore compressionvertebral body height, with the high perfusion group no significantdifference;5. The balloon expansion volume can be used as a reference index of the bone cement perfusion in PKP holds the dose.