骨盆后环骨折脱位不同内固定的生物力学研究

BIOMECHANICAL RESEARCH ON INTERNAL FIXATION METHODS OF POSTERIOR PELVIC RING FRACTURE DISLOCATION

目的比较采用改良Galveston(improved Galveston,IG)、重建钢板(reconstruction plate,RP)、骶骨拉力钉(iliosacral screw,LS)3种内固定方式固定骨盆后环骨折脱位的生物力学差异,为临床选择恰当的内固定方式提供实验依据。方法取自愿捐献成年男性新鲜尸体完整骨盆标本6个,平均年龄45岁。采用MTS855型Mini-Blonix生物力学测定仪分别进行正常骨盆垂直压力(压力800N)与左、右方向扭转(扭矩8N.m)的生物力学测试。之后骨盆标本模拟DenisⅠ型骨盆左侧后环骨折,分别行IG、RP、LS固定骨盆后环,对固定后的骨盆同法行生物力学测试。结果施加垂直压力及左、右方向扭转力时,骨折两端位移从小到大均依次为正常骨盆、LS、IG及RP,LS与正常骨盆间差异无统计学意义(P>0.05),其余两两比较差异均有统计学意义(P<0.05)。结论LS固定骨盆后环骨折脱位较IG及RP稳定。

Objective To investigate the biomechanical differences of three internal fixation approaches,namely improved Galveston （IG）,reconstruction plate （RP）,and iliosacral screw （LS） to the posterior pelvic ring fracture dislocation and provide experimental evidence for the clinical application of proper internal fixation method. Methods Six donated fresh adult cadaver pelvic specimens （age averaged 45 years old） were numbered randomly and their normal biomechanics were tested by the measure instrument （MTS855 Mini-Blonix）. The displacement values of normal pelvis were measured under the vertical compression （800 N） and reverse direction compression （8 N·m）. Then they were made into left Denis I pelvic fracture and fixed with the IG,RP,and LS,respectively,in different orders. Biomechanics test was conducted on the fixed pelvis from both the vertical and the reversed directions. Results Concerning the direction of verticality and torsion,the order of fracture displacement from small to large was the normal pelvis,LS,IG and RP. There was no significant difference between LS and the normal pelvis （P 〉 0.05）,and the differences between other tow groups were significant （P 〈 0.05）. Conclusion The LS fixation can provide better stability for posterior pelvic ring fracture dislocation when compared with IG and RP.