The Biomechanical Study Of L5 Posterior Vertebral Lamina Defect

Background: spina bifida occulta is a relatively common congenital malformations spine diseases,Vertebral column during embryonic development,bilateral vertebral arch is gradually close to the back of the central place until mutual confluence,formation of vertebral canal and continue to develop further extended spines backward,When bilateral vertebral arch to stop development.The bilateral vertebral arch of back is still not mutual fusion.It can produce different degrees of cracks in the spinous process and vertebral arch,If this kind of crack purely for congenital bone defect,and no sedation group bulging backwards from the crack and is called spina bifida occulta.The incidence of spina bifida occulta reported differences between 1.2% and 1.2%,Zhang Junbin think that the incidence of spina bifida occulta is 37.7% [1],but there are more than 80% of the patients have no symptoms at all along,as the modern life rhythm speeding up,we found that more and more lumbar disc herniation in young and middle-aged patients(20-40 years old),especially The patients of waist 5 to s1 intervertebral disc herniation,they are no history of trauma,and the job is also light manual labor.This aroused our great interest,after conventional X-ray on these patients,we found that these patients have different degrees of waist 5 vertebral plate defect.So far,there are no any L5 lamina portion defect biomechanics research literature reports.Objective: with the change of the modern human lifestyle,Some not obvious symptoms of the spina bifida occulta happened also more and more.spina bifida occulta patients compared with healthy people of their peers,Patients with spina bifida occulta compared with peers in the healthy population,whether it is more likely to suffer from L5 to S1 disc herniation? Are L5 posterior vertebral lamina defect will accelerate L5 to S1 disc herniation? we are trying through biomechanical,confirmed spina bifida occulta than healthy people of their peers,they are more likely to suffer from L5 to S1 disc herniation,and L5 posterior vertebral lamina defect will accelerate L5 to S1 disc herniation.So we can actively take preventive measures to reduce the spina bifida occulta patients of L5 to S1 disc herniation occurs,Reduce the psychological and physical suffering of patients and reduce the financial burden borne by the family and society.Methods: Choose eight fresh-frozen cadaveric specimens adult sheep,Select the adult sheep carcasses spine of L5 to sacral vertebrae and intervertebral disc as experiment samples,Carefully removing the surrounding muscle tissue,But keep the anterior longitudinal ligament,posterior longitudinal ligament,yellow ligament,the ligament,interspinous ligament and L5 to S1 intervertebral disc to complete.A total of 16 vertebral and eight disc,Adult sheep slaughter ages 2 to 3 years,Using 500 mA Siemens DR radiography machine to test specimens taken X-ray ruled out cancer,tuberculosis,trauma,fractures and congenital malformations and other diseases.Choose eight fresh-frozen cadaveric specimens adult sheep,Select the adult sheep carcasses spine of L5 to sacral vertebrae and intervertebral disc as experiment samples,.This experiment can be divided into experimental and control groups,Do first experimental control group,the experimental group was doing,Adult sheep spines samples numbered into: 1,2,3,4,5,6,7,8,Each spine samples with adult sheep of self-control by experimentally before and after the intervention.Control group: 8 adult sheep lumbar spine samples from L5 to S1 vertebral segments,It contains a complete disc and the surrounding ligaments.The L5 to S1 Intervertebral disc integrity,anterior longitudinal ligament,posterior longitudinal ligament,yellow ligament,interspinous ligament and the ligament are all intact,the facet joint capsule intact,lumbar 5 and sacral 1 vertebral bone integrity.Experimental group: Using rongeur to remove adult sheep L5 posterior vertebral lamina half In the control group based on experimental samples,During we are not to damage the surrounding ligament,interspinous ligament,posterior longitudinal ligament,anterior longitudinal ligament,facet joint capsule,spinous process and facet joint bone.All experiment samples of adult sheep L 5 to S1 vertebrae were fixed on the biomechanical testing machine one by one to load,we will use hierarchical load to load experimental samples of adult sheep L 5 to S1 vertebrae.Compressed motion at a set axial load,Measurement adult sheep spine between lumbar 5 to the sacral 1 vertebral disc space height,and change the load,Intervertebral height will be test under different loads and record the data.The above experimental data were statistically analyzed by SPSS.Results: The control group of the same adult sheep spines loaded with load increases,between L5 to S1 vertebral disc height increases gradually,experimental group the same sample is also loaded with a load increases,between L5 to S1 vertebral disc height increases gradually.In the case of the same load,the experimental group of between L5 to S1 vertebral disc height is greater than the control group.However,the experimental data by the statistical test analysis,there were no significant differences at different loads(P>0.05),no statistically significant(P> 0.05).Conclusion: Spina bifida occulta patients(L5 lamina portion defect)compared with healthy people,the L5 to S1 disc of spina bifida occulta patients to bear greater pressere,Spina bifida occulta patients(L5 lamina portion defect)compared with healthy people,the L5 to S1 disc of spina bifida occulta patients are more occur to degeneration.This experiment study from the perspective of biomechanics confirmed the recessive spina bifida patients(L5 lamina portion defect)compared with healthy people prone to waist 5 to s1 intervertebral disc herniation.