骨质疏松性椎体骨折患者胸腰椎椎体后壁形态学测量及临床意义

The morphological measurement and clinical significance of thoracic and lumbar vertebral posterior wall in patients with osteoporotic vertebral fracture

目的 :探讨骨质疏松性椎体骨折(osteoporotic vertebral fracture,OVF)患者胸椎、腰椎椎体后壁形态学差异及其临床意义。方法:选取我院2013年1月~2016年12月收治的临床资料完整的98例OVF患者,采用CT三维重建技术及多平面重建技术(multiplanar reconstruction,MPR)观察测量T6~L5椎体相关参数。测量椎体纳入标准:椎体无新鲜或陈旧性骨折、无感染征象、无肿瘤性骨质破坏、无半椎体及阻滞椎等先天畸形等;排除标准:已行经皮穿刺椎体后凸成形术(percutaneous kyphoplasty,PKP)治疗的椎体。测量T6~L5椎体CT影像的如下参数:双侧椎体后缘线与椎弓根中轴层面的内侧骨皮质处的交点A、B的连线(AB),骨性椎管凸入椎体顶点O到线AB的距离(OC),椎体最前缘点P到AB的距离(PC),计算R=OC/PC(术中侧位像上骨性椎管凸入椎体深度与椎体中矢状径比值)。采用独立样本t检验比较T12与L1椎体OC值。结果:OC值自T6至T12在3.83±0.13mm到5.21±0.06mm之间,PC值自T6到L5在23.42±0.21mm到44.38±4.51mm之间,均呈逐渐增大趋势。OC值自T12至L5在5.21±0.06mm到0mm之间,呈逐渐减小趋势。R值在T6~T12均接近0.16(1/6),腰椎较胸椎明显减小,在L1~L3明显小于1/6,在L4、L5接近于0。T12与L1的OC值差异有统计学意义(P<0.05)。结论 :中下胸椎椎体后壁形态与腰椎相比存在明显差异,OC的存在致中下胸椎椎体后壁在侧位像上的真实投影线位于椎体后1/6处。在中下胸椎行PKP时尽量避免骨水泥分布超过椎体后1/6从而减少骨水泥椎管内渗漏的发生。

Objectives： To investigate the difference of thoracic and lumbar vertebral posterior wall morphology in patients with osteoporotic vertebral fracture and its clinical significance. Methods： 98 patients with complete detailed data were enrolled in this study from January 2013 to December 2016, the related parameters of the T6-L5 vertebral were observed and measured through the CT 3D reconstruction and multiplanar reconstruction（MPR）. Inclusion criteria were without fresh or old fracture of vertebral body, without infection, tumor, hemivertebral body and obstructive vertebral deformity. Exclusion criteria were the vertebral bodies that had been treated with percutaneous kyphoplasty（PKP）. The following parameters were measured and analyzed by using CT image from T6 to L5： （1）AB, the distance between the junctions of the posterior border of bilateral vertebral body and the medial cortical at the axial plane of vertebral arch; （2）OC, the distance between line AB and point O（the top point of spinal canal intruded into the relative vertebral body）; （3）PC, the distance between line AB and the top point of anterior edge of body; （4）R=OC/PC was calculated（in the C arm fluoroscopy lateral imaging, the ratio of the lumbar of vertebral disc to the sagittal diameter of vertebral body）. To compare the OC values of T12 and L1 through independent sample t test. Results： The range of PC values from T6 to L5 was from 23.42±0.21mm to 44.38±4.51mm, the OC value from T6 to T12 was from 3.83±0.13mm to 5.21±0.06mm, the data from two groups were gradually increasing. The OC value from T12 to L5 was from 5.21±0.06mm to 0mm, which was gradually decreasing. The R value from T6 to T12 was close to 0.16（1/6）, compared with thoracic vertebra, the lumbar vertebra decreased significantly, which was significantly less than 1/6 in L1 to L3, and was close to 0 in L4 and L5. The difference between the OC values of T12 and L1 was statistically significant（P〈0.05）. Conclusions： The posterior wall morphology of thoracic vertebral body is significantly different from that of lumbar vertebra, and the OC structure causes the posterior wall of the middle and lower thoracic vertebral body to be located in the posterior of the vertebral body 1/6. Due to the presence of OC structure in the middle and lower thoracic vertebra, it is possible to reduce the occurence of bone cement leakage into spinal canal through avoiding bone cement distribution over the posterior 1/6 of vertebral body in PKP.