Effection Of+Gz And Weightlessness On The Animal Lumbar Intervertebral Disc Early Clinical Application Of Expansive Open-door Laminoplasty By Arch Titanium Plate Reconstitution For Cervical Spinal Stenosis

Objective Lower back pain (LBP) often bothers aviators during or after flight and the causes are usually degenerative disc diseases (DDD). It has been speculated that the causes of degeneration may be related to the flight environment of high load(+Gz) and weightless. In this study, we use animal models of+Gz and simulated weightlessness models to explore the degenerative mechanism of animal intervertebral disc under+Gz and simulated weightlessness environment, in an effort to provide experimental basis for the prevention, delay and cure of aviators lumbar disc degeneration, for the improvement of the training mode and, and for possible portable protection.Method One hundred and twenty healthy male New Zealand rabbits were randomly divided into+Gz group, simulated weightlessness group,+Gz/simulated weightlessness group and control group. Rabbits in each of these groups were further divided into3sub-groups of30、60d and90d.Rabbits in these groups were exposed to corresponding research conditions and were killed by ear vein air embolism after imaging on30days,60days and90days. Pathological and immunohistochemical staining of L6-S1disc is performed. Analysis of variance was used to compare the statistical difference of every groups and P<0.05was regarded as statistically significant; analysis of variance was used to compare the statistical difference of different sub-groups, P<0.05was regarded as statistically significant.Result (1) Histomorphology:Through routine pathological staining of all L6-S1discs and observation under microscopic, little proliferation of nucleus pulposus cells and cell clusters in the control group was found, the annulus fibrosus was distributed in clear order. There was nucleus pulposus cells proliferation in30d of the experimental group, distributed as single or clusters cells, loose extracellular matrix and evenly distributed annulus fibrosus. Reduction of nucleus pulposus cells, many clusters cells, and partial fibrosis of nucleus pulposus can be observed in60d and90d of the experimental group. The compensated enlargement of cell cores was observed in the connection of the annulus fibrosus and nucleus pulposus cells. Statistical differences (P<0.05) were found in the percentage of cell clusters in total cells between experimental groups and the control group, and between all sub-groups with the same durations. The percentage of the clusters cells in the total cells increase as exposure prolonged.(2) Immunohistochemistry:The MMP-1,3(mateix metalloproteinases,MMP-1,3) immunohistochemical staining of all L,6-S1discs and microscopic observation showed that the positive expression of MMP-1,3is little in30d and60d control groups and we can see little positive expression of MMP-1,3in90d control group as the nucleus is blue-stained and endochylema is tan. The positive expression of MMP-1,3is many in all experimental groups-mainly in cell clusters cells as the nucleus is blue-stained and endochylema is tan. The rates of MMP-1,3positive expression in total cells is statistically different (P<0.05) between all sub-groups of experimental groups and control group.(3) Comparing experimental groups and control groups, there were no disc degenerative changes in AP and lateral X-ray of lumbar, CT scan of the disc and MRI scan.Conclusion+Gz and simulated weightlessness exposures for intermediate stage may induce early degenerative pathological changes of animal lumbar intervertebral disc. The effects of high load and simulated weightlessness on disc degeneration mechanism are cooperative. The degree of degenerative severity increases as the exposure time extends. The study suggests that+Gz and weightlessness environment were likely to cause and accelerate the aviators’lumbar intervertebral disc degenerative process. Objective To evaluate the early clinical application of expansive open-door laminoplasty with Arch titanium plate reconstruction for cervical spinal stenosis.Methods From April2010to June2012,25cases suffering from cervical spinal stenosis underwent expansive open-door laminoplasty with Arch titanium reconstruction. Recorded the VAS score、Japan Orthopaedic Association(JOA)score at preoperatrive and postoperative. The sagittal diameter of spinal canal(mean of the sagittal diameter of C3～C7spinal canal) before operation and7days,6months after operation respectively also were recorded.The reduction of neck and shoulder pain was evaluated by VAS score.The neurofunction was evaluated by JOA score and its improvement rate;X-ray,CT and MRI were used to evaluate postoperative spinal canal enlargement and bone fusion at the hinge side.The sagittal diameter of C5spinal canal on the lateral X-ray was measured before operation and7days,6months after operation respectively,and the expansion rate of spinal canal was calculated.All the intraoperative and postoperative complications of every patient were also recorded.Results The follow up period of every patient was not less than6months. Axial symptoms、C5palsy and cerebrospinal fluid leakage were noted in3cases after operation,which were relieved significantly after correspondent intervention. There is no recurrence of cervical stenosis and neurofunction deterioration after operative.Every patient got symptomatic relief.There were significant differences between preoperative and postoperative with regard to JOA score (P<0.05).The average JOA score improvement rate is (57.05±16.97)%after operation,with the efficiency rate of72%.Radiographic findings showed spinal canal enlarged perfectly and bony fusion at hinge side at7days and6months after operation.Compared the C5segment sagittal diameter7days or6months after operation with preoperative,the differences were statistically significan (P<0.05). There were no significant differences with regard to sagittal diameter between the postoperative two groups (-P>0.05).The expansion rate of spinal canal after operation is (97.74±9.06)%.Conclusion Among expansive open-door laminoplasty,the application of Arch titanium plate is a simple、reliable and safe method to cure cervical spinal stenosis,and the early clinical efficacy is satisfactory.