Study On The Correlation Between The Posterior Morphology And Spinal Stenosis Of Thoracolumbar Vertebral Fracture And The Effection Of Vertebral Bone Healing To Suppress The Sclerostin

Part Ⅰ: Correlation analysis between thoracolumbar fractures vertebral posterior morphology and spinal canal stenosis【Objective】: To investigate the relationship between the thoracolumbar burst fracture vertebral bone block morphology, spinal canal occupying rate measured by X-ray and CT and the indirect reduction effection of fracture, it would provide a clinical theoretical support for the diagnosis of different types of thoracolumbar burst fracture and the intraoperative spinal cord decompression.【Methods】: A retrospective study was done on 134 cases of thoracolum barburst fractures treated in our hospital.A comprehensive evaluation was carried out according to the clinical symptoms, physical signs and imaging examinations of the patients.The correlation analysis was performed on the basis of the Frankel rating system to evaluate the sensory and motor function of patients with different injury segments.We measured the canal occupying rate by lateral X-ray and CT,and then analyzed the relationship between them.To observe the distribution of posterior bone morphology in different segments,we analyzed the correlation between different types of posterior bone morphology and the indirect reduction effection of vertebral fracture.【Results】: There was a significant relationship between the spinal cord nerve function and the canal occupying rate in the 134 patients(P<0.05);and at the level of T12 and L1, there was a high correlation between the degree of spinal cord injury(r=0.873, 0.735), and the same result at the level of T11 and L2(r=0.546, 0.594).There was a significant correlation between lateral X-ray occupying rate and CT occupying rate in the 134 cases with thoracolumbar vertebral fracture(P<0.05);There was a high correlation(r=0.823, 0.716) between and T11 and L2, while the level of T12 and L1 was significant correlated(r=0.615, 0.567).According to the morphology of the posterior fracture bone block measured by standard lateral X-ray of the 134 patients,it is divided into the four types: the circular arc, spoon shaped, the polygon and other type.The results showed that the main type of T11 was circular arc,of T12 were circular arc and spoon shaped,while of L1 and L2 were spoon shaped.By observing the 59 cases without spinal canal decompression,we found that the distribution of the types were the spoon shaped in 29 cases(49.2%), the circular arc in 17 cases(28.8%), the polygon in 6 cases(10.2%), and the other types in 7 cases(11.9%).It suggested that the types of the circular arc and spoon shaped fracture would be obtained a effective indirect reduction.【Conclusion】: During the treatment of thoracolumbar burst fracture patients, The measuring of the spinal canal occupying rate by X-ray is effective,and the morphology of the posterior vertebral fracture can tell us the effection of the indirect reduction.It will provided a simple monitoring method for spinal surgeons.Part II:Clinical application on the indirect reduction by measuring the posterior morphology of thoracolumbar vertebral fracture【Objective】: To evaluate the clinical value of "canal occupying rate and the vertebral fracture morphology measured by standard lateral X ray in the treatment of thoracolumbar burst fractures.【Methods】: Under X-ray assisted, 140 cases of thoracolumbar burst fractures were treated with short segment pedicle screw internal fixation system.The patients were divided according to the canal occupying rate measured by lateral X-ray after distraction of pedicle screw rod system in the operation,>30% was in the direct decompression group and <30% was in the indirect reduction group,.(1)the direct decompression group:after distraction of pedicle screw rod system,we decompressed the vertebral canal by incision of unilateral or bilateral vertebral plate.(2)indirect decompression group:We only fixed and distracted with pedicle screw system.The general situation of two groups were compared and analyzed with no statistical significant differences.The spinal nerve function was evaluated according to the Frankel rating of two groups of patients before surgery and after the last follow-up.A comparative analysis were carried out between two groups with anterior vertebral body height(AVH), posterior vertebral height(PVH), posterior arch angle(Cobb),vertebral canal occupying rate and the morphology of vertebral fracture.All patients were followed up for more than 6 months.At the time of the last follow-up we evaluated the curative effection using the VAS and ODI score system.【Result】: The two groups were operated successfully, and the anterior vertebral body height(AVH), posterior vertebral body height(PVH), posterior arch angle(Cobb angle) were significantly differences compared with preoperation(P<0.05).But there were no significant differences between the two groups(P>0.05). Neurological function had a Good recovery in the two groups,and there were no significant differences between the two groups with neurological function improvement in the level of Frankel 1(P>0.05).There were significant differences between different fracture morphology types with severity and recovery of the spinal cord injury.At the last follow-up visit,comparied with preoperative score,the VAS score and ODI index of the two groups were significantly improved, the differences were statistically significant(P<0.05),but there were no significant differences between the two groups(P>0.05).【Conclusions】: During the treatment of thoracolumbar burst fracture patients,spinal canal occupying rate measured by standard lateral X-ray can effectively reflect the intraspinal occupying degree,combined with a continuous and smooth "linear shadow" on posterior vertebral body wall imaging is a simple and efective way to judge the reduction of bone fragment.Comparied with polygon,the spoon shaped and circular arc morphology of the vertebral fracture had less severity and better recovery of spinal cord injury,also had the more successful reduction of the fracture bone.So it maybe provide the reference on whether decompressing the spinal canal and guide the operative plan of thoracolumbar fracture.Part III: Sclerostin Suppression Increases BMP-4-Induced Osteogenesis of human Mesenchymal Stem Cells 【Objective】:To further examine the in vitro proliferation and BMP-4-induced osteogenic differentiation effects of Sclerostin on human bone marrow-derived mesenchymal stem cells(MSCs).【Methods】: Sclerostin-specific small interfering RNA(si RNA) was developed to inhibit the Sclerostin expression of human MSCs. Moreover, the mitochondrial dehydrogenase activity, cell proliferation were detected to evaluate the viability of human MSCs. Furthermore, the osteogenic differentiation of human MSCs induced by BMP-4 was assessed by measuring the enzymatic alkaline phosphatase(ALP) activities and calcification and the expression levels of some osteoblastic genes were also analyzed through real-time PCR.【Result】: Results showed that human MSC metabolism and proliferation increased drastically on Days 3 and 7 after Sclerostin inhibition.The depression of Sclerostin also increased the expression levels of osteocalcin(OCN), osteocalcin(OC), and osteopontin(OPN). Enzymatic ALP activity and calcium deposits in Sclerostin-inhibited group increased obviously.【 Conclusion 】 : Sclerostin suppression could retain viability and promote BMP-4-induced osteogenic differentiation of human MSCs which can be indicated that Sclerostin contributed to the osteogenesis suppression of human MSCs.