多层螺旋CT评价脊柱融合模型成骨过程的研究

Assessment of Osteogenic Ability of Spinal Fusion Model Using Multislice Computed Tomography

目的分析自体骨成骨与硫酸钙成骨的CT表现,结合同期病理学结果,探讨影像改变的病理机制。材料与方法20只健康家兔建立腰椎融合模型,一侧植入医用硫酸钙,对侧植入自体髂骨。于术后3、6、12周行手术部位多层螺旋CT(MSCT)检查,观察植入物与自体骨融合状况。于术后12周,根据CT表现计算植骨融合率及MSCT评估腰椎融合的敏感度、特异度、阳性预测值(PPV)及阴性预测值(NPV)。术后3、6周各随机处死1只家兔,获得同期病理对照,术后12周处死剩余18只家兔,获得最终时间点病理对照。结果 MSCT评估硫酸钙植骨一侧腰椎融合的敏感度、特异度均为100.0%,自体髂骨植骨侧分别为94.1%和100.0%。术后12周,硫酸钙植骨一侧融合率为88.9%(n=16),PPV为94.1%,NPV为100.0%;自体髂骨植骨一侧融合率为94.4%(n=17),PPV为100.0%,NPV为50.0%,两侧融合率差异无统计学意义(P>0.05)。结论 MSCT能够有效评价脊柱融合术后骨移植材料的成骨表现。

Purpose To evaluate calcium sulfate performance in the traverse process of vertebra using CT with histopathology as standard of reference.Materials and Methods Twenty rabbits undergoing surgeries of lumbar spinal fusion,intervertebral fusion and inter-transverse process bone graft were included in this study.An injectable form of calcium sulfate was implanted into the left traverse process in healthy rabbit.In comparison,autologous-iliac bone graft was implanted into the right traverse process of the same vertebra.Morphologic analysis of calcium sulfate as well as the subsequent bone response to calcium sulfate based on CT imaging was performed at 3,6 and 12 weeks after implantation with histopathology as standard of reference.The sensitivity,specificity,positive predictive value,and negative predictive value for detecting fusion were calculated for MSCT scans by comparing the results of surgical exploration.Results MSCT scans had sensitivity and specificity of 100.0% for calcium sulfate fusion.For autologous-iliac bone graft fusion,the sensitivity was 94.1% and specificity 100.0%.No statistical significance was demonstrated in bone graft fusion between autologous-iliac bone and calcium sulfate at 12 weeks （P 〉 0.05）.The positive predictive value for calcium sulfate fusion was 94.1%;negative predictive value was 100.0%.The positive predictive value for autologous-iliac bone graft fusion was 100.0%,negative predictive value was 50.0%.Conclusion CT imaging can be used to evaluate osteogenic process after lumbar spinal fusion.