The Study And Clinical Application Of Spinal Shortening To Protect Spinal Cord During PVCR Operation For Spinal Deformity

Objectives:1.The effects of different orthopedic operations on spinal cord blood flow,neuroelectrophysiology,and microcirculation metabolites in pigs with spinal deformity were studied by establishing a pig spinal deformity model.2.To study whether proper spinal shortening can protect the spinal cord function by avoiding th e increase of neuron calcium ion,calpain and Caspase-3 expression.3.To investigate the effect of proper shortening of the spine on the blood flow of the spinal cord,neuroelectrophysiology,and spinal cord function in patients with severe spinal deformity using PVCR technology.Methods:1.Establishment of spinal deformity model:18 experimental pigs of 2 months old were selected to establish the spinal deformity model by the tethering method,and X-ray examination was performed after feeding for 2 months after the modeling operation.2.Intraoperative electrophysiological monitoring(IOM)and Spinal cord blood flow(SCBF):The pigs with spinal deformities successfully modeled were selected and randomly divided into non-osteotomy group,2/4 group and 0/4 group.Among them,the experimental animals in the non-osteotomy orthopedic group directly used the nail-rod system for orthopedics.The 2/4 group used PVCR technique for orthopedics,and after the vertebral body resection was completed,shortened 1/2 of the vertebral body osteotomy space containing the upper and lower vertebral discs for orthopedic treatment.Group 0/4 used PVCR technology to perform orthopedic surgery without spinal shortening.Each experimental group used a laser Doppler flowmeter to monitor the SCBF at each critical stage of the operation,and the intraoperative nerve electromyography was used to monitor the intraoperative nerve electrophysiology.3 After the operation was completed,spinal cord specimens were taken for the detection of endothelin-1 and heme oxygenase-1 by Elisa method.4.Pathological examination:The above spinal cord specimens were observed under HE staining light microscope.5.The above specimens were taken for calcium ion detection in nerve cells,calpain expression content(western blot)detection,caspase-3 expression(immunofluorescence labeling method)detection,and calpain activity detection.6.Clinical research:Patients with severe rigid kyphotic deformity using PVCR technology for orthopedics and vertebral resection level higher than L1 were selected,and neurological function tests were performed before and after operation.During the orthopaedic process,laser Doppler flowmeter was used to monitor the spinal cord blood flow at different stages of operation,and nerve myoelectricity monitor was used to monitor the whole process of nerve electrophysiology during the operation.Results:1.A total of 18 pigs with spinal deformity were successfully established.The average Cobb angle in the coronal position was 57.3±3.9 degrees,and the Cobb angle in the sagittal plane was 23.9±3.2 degrees.2.SCBF:a.Spinal deformity model group(n=18)are certain differences in the convex and concave sides of the SCBF,the concave side is 305.0±47.0PU,the convex side is 312.7±33.8PU,of which 61.1%of the experimental animals' concave side SCBF is lower than the convex side Side,but there is no statistical difference between the concave and convex sides(p>0.05).b.b.In the SCI group(n=6),the spinal cord blood flow decreased significantly after the spinal cord injury was modeled,and the SCBF decreased from 317.8±39.4PU to 130.4±32.5PU.It dropped to 41.7%at the time of laminectomy.c.In the non-osteotomy group(n=6),the SCBF was 310.8±37.8PU during laminectomy and 290.5±33.5PU after orthopedics.After 30 minutes of orthopedics,it was 288.7±35.1 PU.d.After vertebral column resection(VCR),SCBF dropped to 78.5%at the time of laminectomy(n=12).e.The SCBF of group 0/4 was 306.1 ±42.01PU after laminectomy,and decreased to 239.2±37.1PU after VCR.There was a statistical difference between the two(p<0.05).After orthopedics,it was further lowered to 218.5±36.4 PU,and it decreased again 30 minutes after the orthopaedic completion.At this time,the spinal cord blood flow was 202.8±24.0 PU.The SCBF of the 2/4 group was 310.5±48.7PU after laminectomy,and decreased to 245.8±43.3PU after VCR.There was a statistical difference between the two(p<0.05),and it increased to 321.1±40.9 after spinal shortening.After orthopedics,the drop was 285.9±34.5PU.It returned to 299.8±44.2PU 30 minutes after the orthopaedics.3.IOM results:Only the SCI group caused IOM alarms,other groups did not have IOM alarms.4.Hemoglobin oxygenase-1(HO-1)content:Control group was 0.095±0.019U/mg,non-osteotomy group was 0.120±0.027 U/mg,0/4 group was 0.165±0.025U/mg,2/4 group was 0.154±0.016 U/mg,SCI group was 0.175± 0.027U/mg.5.Endothelin-1(Et-1)content:2.47±0.22ug/g in the Control group,2.38±0.34ug/g in the non-osteotomy group,3,68±0.48ug/g in the 0/4 group,and 2.57±in the 2/4 group 0.47ug/g,SCI group was 6.03 ±1.19ug/g.5.Pathological results:Compared with the Control group,the neuron cells in the non-osteotomy orthopedic group and the 2/4 group showed no obvious abnormalities;0/4 neuron cells had mild edema;and SCI had obvious necrosis.6.Calcium in nerve cells:Compared with the Control group,the fluorescence intensity of the non-osteotomy group and the 2/4 group did not increase significantly,the 0/4 fluorescence intensity was higher,and the SCI group increased significantly.7.Calpain content and activity:Compared with the Control group,the expression and activity of calpain in the non-osteotomy orthopedic group and the 2/4 group did not increase significantly.The 0/4 calpain expression was higher,and the SCI group was significantly higher.8.caspase-3:Compared with the Control group,the expression of caspase-3 in neurons of the non-osteotomy group and the 2/4 group did not increase significantly,the expression of 0/4 caspase-3 was higher,and the SCI group increased significantly.9.A total of twelve patients with severe rigid kyphosis were included.The SCBF was 316.4 ± 86.1 PU during laminectomy,and decreased to 228.2±67.5 PU after VCR(p<0.05).After the first shortening and correction,SCBF increased to 241±76.8 PU,and after the middle shortening and correction,SCBF increased to 296±99.6 PU,which was a 121%increase compared to SCBF after VCR.SCBF reduce to 270.9 ± 65.4 PU after final fixation.IOM was negative in all patients,and MEP and SSEP did not reach the alert values at the time of surgery.Conclusions:1.Compared with non-osteotomy,PVCR technology has a greater impact on spinal cord blood flow and microcirculation metabolism,but proper spinal shortening can significantly reduce this effect.2.Appropriately shortening the spinal column during PVCR orthopedic surgery to reduce spinal cord tension can inhibit the activation of the calpain signaling pathway and protect nerve cells,thereby increasing the spinal cord's tolerance to subsequent spinal orthopedic procedures.3.The effects of different steps on severe spinal deformity PVCR orthopedics have different characteristics on spinal cord blood flow;proper spinal shortening before orthopaedics can improve spinal cord tension,protect spinal cord blood perfusion,and effectively prevent intraoperative spinal cord injury.