颈胸段脊柱在模拟肿瘤破坏状态下稳定性预测的生物力学研究

Biomechanical Study on the Stability of the Cervicothoracic Spine Damaged by Tumors in the Simulated Situation

目的评价颈胸段脊柱在模拟溶骨性肿瘤破坏的情况下的生物力学特性。从而为采取预防性稳定手术提供理论依据。方法取12具新鲜冷藏人体尸体脊柱标本(C7～T2),胸椎带有肋椎关节,分别进行完整标本和模拟颈胸段脊柱肿瘤溶骨性破坏状态时的生物力学测试。测试肿瘤破坏椎体面积的大小(完整标本,30%、40%、50%和90%的面积破坏)对脊柱稳定性的影响。结果椎体破坏面积从完整标本,30%、40%、50%和90%的面积破坏时,其屈服载荷分别为3549±254N、3203±223N、2822±182N、2707±174N和2510±176N。刚度分别从正常完整标本的910±210(N/mm),下降至781±90(N/mm)、664±60(N/mm)、585±40(N/mm)和482±30(N/mm)。T1椎体破坏面积在30%和40%时的屈服载荷有统计学显著性差异。结论在一定范围内,椎体破坏面积大小与椎体屈服载荷呈线性关系。颈胸段T1椎体在破坏面积达40%后,因稳定性下降容易出现椎体塌陷骨折和节段不稳,可作为外科采取预防性稳定手术的参考依据。

Objective To evaluate the biomechanical effects of the tumor size on the failure load of the cervicothoracic vertebrae by using human spine model simulating the osteolytic metastases. Methods Twelve specimens obtained from human cervicothoracic spine wet, used. Each specimen comprised three vertebrae （C7～T2） with intervertebral discs and ribs. The trabecular defects simulating the oste. olytic metastases were created within the T1 vertebral bodies. The specimens with various sizes of the vertebral defect （0%, 30%, 40% , 50% , 90% , in cross sectional area） were subjected to testing. Results The failure load were 3549 ±254 N、 3203 ± 223 N、 2822±182 N、 2707 ± 174 N and 2510 ± 176 N respectively when the defect area of the vertebrae were 0% , 30% , 40% , 50% ant 90% , respectively. The relation between the failure load and defect sizes within vertebral body was studied and there was statistical difference between the 30% defect area and the 40% defect area. Conclusion The defect area of the vertebral body is proportional to th, vertebral failure load in a certain extent. If the defect area of the vertebral body （T1） in the cervicothoracic spine is greater than 40 % the vertebral body will be subjected to instability and is potentially unstable against the destructive force.