Zhu Rui, Cheng Li-ming, Yu Yan, Zander Thomas, Chen Bo, Rohlmann Antonius
Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, 389 Xincun Road, 200065 Shanghai, PR China.
Clin Biomech (Bristol). 2012 Oct;27(8):771-6. doi: 10.1016/j.clinbiomech.2012.05.008. Epub 2012 Jun 16.
After total sacrectomy, it is mandatory to reconstruct the continuity between the lumbar spine and the pelvis. Only few biomechanical analyses exist which compare different reconstructions. Therefore, the aim of this study was to compare the lumbo-pelvic motion and the relative risk of implant breakage for four different reconstructions after total sacrectomy.
Finite element analyses were performed for four general different reconstructions after total sacrectomy: sacral-rod reconstruction, four-rod reconstruction, bilateral fibular flaps reconstruction, and improved compound reconstruction. The rotations between L5 vertebra and ilium, the L5 shift-down displacement, and the maximum von Mises stress in the implants were calculated and evaluated for flexion, extension, lateral bending and axial rotation.
The decreasing order of the rotations between L5 vertebra and ilium as well as of the L5 shift-down displacement for the studied reconstruction methods was four-rod reconstruction>sacral-rod reconstruction>bilateral fibular flaps reconstruction>improved compound reconstruction. The decreasing order of the maximum von Mises stress in the implants was sacral-rod reconstruction>four-rod reconstruction>bilateral fibular flaps reconstruction>improved compound reconstruction.
From the mechanical point of view, improved compound reconstruction is superior to the other methods studied here as it shows the highest stability and the lowest maximum von Mises stress. However, clinical aspects must also be regarded when choosing a reconstruction method for a specific patient.
全骶骨切除术后，重建腰椎与骨盆之间的连续性是必要的。仅有少数生物力学分析比较了不同的重建方法。因此，本研究的目的是比较全骶骨切除术后四种不同重建方法的腰骶部运动及植入物断裂的相对风险。
对全骶骨切除术后四种一般不同的重建方法进行有限元分析：骶骨棒重建、四棒重建、双侧腓骨瓣重建和改良复合重建。计算并评估L5椎体与髂骨之间的旋转、L5向下移位以及植入物中的最大冯·米塞斯应力，分析其在屈曲、伸展、侧方弯曲和轴向旋转时的情况。
对于所研究的重建方法，L5椎体与髂骨之间的旋转以及L5向下移位的递减顺序为：四棒重建>骶骨棒重建>双侧腓骨瓣重建>改良复合重建。植入物中最大冯·米塞斯应力的递减顺序为：骶骨棒重建>四棒重建>双侧腓骨瓣重建>改良复合重建。
从力学角度来看，改良复合重建优于此处研究的其他方法，因为它显示出最高的稳定性和最低的最大冯·米塞斯应力。然而，为特定患者选择重建方法时，还必须考虑临床因素。
