Truumees Eeric, Demetropoulos Constantine K, Yang King H, Herkowitz Harry N
William Beaumont Hospital, Royal Oak, MI, USA.
Spine (Phila Pa 1976). 2003 Oct 1;28(19):2204-8. doi: 10.1097/01.BRS.0000084881.11695.50.
An in vitro biomechanical study using a servohydraulic testing machine on cadaveric endplates.
To characterize the effects of bone mineral density, endplate geometry, and preparation technique on endplate failure load.
The effects of endplate preparation methods on failure loads are only partly characterized in the literature. Endplate burring has been recommended to increase fusion rates. However, graft subsidence may complicate anterior reconstruction procedures.
After radiographic screening, 21 cadaveric cervical spines underwent dual-energy x-ray absorptiometry scanning to quantify mineral content. Endplate geometry was calculated in 55 randomly selected endplates from the inferior C2 to the superior T1 levels. These vertebrae were embedded in polyester resin and randomly left intact, perforated, or burred. The cervical endplates were loaded at a rate of 0.2 mm/s on an Instron materials tester with an attached 9 mm diameter polycarbonate rod (an area of 64 mm2). A stepwise, univariate linear regression was used to compare the point of endplate failure with the vertebral level, endplate area, gender, age, bone mineral density, and preparation technique.
Mean bone mineral density, as measured by dual-energy x-ray absorptiometry, was 0.713 g/cm2 (+/- 0.173 g/cm2). Mean endplate area was calculated at 323 mm2. A mean compressive force of 754 N (+/- 445 N) was required before endplate failure. Trends toward increasing compressive loads were noted with decreasing endplate area and increasing bone mineral density. Increasing age (P = 0.0203), caudal vertebral level (P < 0.0001), endplate burring (P = 0.0068), and female gender (P = 0.0452) were associated with significantly lower endplate fracture loads in compression.
Bone quality was predictive of endplate compressive failure loads. Intact endplates failed at significantly higher loads than their perforated or burred counterparts.
一项体外生物力学研究，使用伺服液压试验机对尸体终板进行测试。
描述骨密度、终板几何形状和制备技术对终板破坏载荷的影响。
文献中仅部分描述了终板制备方法对破坏载荷的影响。有人建议进行终板打磨以提高融合率。然而，植骨下沉可能会使前路重建手术复杂化。
经影像学筛查后，对21个尸体颈椎进行双能X线吸收测定扫描以量化矿物质含量。从C2下至T1上水平随机选取55个终板计算其几何形状。将这些椎体嵌入聚酯树脂中，并随机保持完整、打孔或打磨。在配备直径9毫米聚碳酸酯杆（面积为64平方毫米）的英斯特朗材料试验机上，以0.2毫米/秒的速率对颈椎终板施加负荷。采用逐步单变量线性回归比较终板破坏点与椎体水平、终板面积、性别、年龄、骨密度和制备技术之间的关系。
通过双能X线吸收测定法测得的平均骨密度为0.713克/平方厘米（±0.173克/平方厘米）。平均终板面积计算为323平方毫米。终板破坏前所需的平均压缩力为754牛（±445牛）。随着终板面积减小和骨密度增加，压缩载荷有增加的趋势。年龄增加（P = 0.0203）、椎体水平靠下（P < 0.0001）、终板打磨（P = 0.0068）和女性（P = 0.0452）与终板压缩骨折载荷显著降低相关。
骨质量可预测终板压缩破坏载荷。完整终板的破坏载荷明显高于打孔或打磨后的终板。
