后凸成形骨水泥强化技术对骶骨钉固定强度的生物力学影响  

Biomechanical effect of kyphoplasty-assisted PMMA augmentation on the sacral screw fixation strength

作　　者：于滨生[1] 郑召民[1] 庄新明[1] 李泽民[1] 王泰平[1] 

机构地区：[1]中山大学附属第一医院脊柱外科,广州510700

出　　处：《中国骨质疏松杂志》2010年第4期251-255,共5页Chinese Journal of Osteoporosis

基　　金：广东省科科技计划重点项目(2008B050100012)

摘　　要：目的评价后凸成形骨水泥(Polymethylmethacrylate,PMMA)强化技术对骨质疏松情况下骶骨钉固定强度的生物力学影响,为骶骨钉松动选择坚强的补救技术提供依据。方法11具新鲜骶骨标本用于实验,并采用DEXA评价标本骨密度。在同一骶骨标本上,依次建立非PMMA强化和PMMA强化骶骨钉的固定模型如下,A组:单皮质椎弓根钉;B组:双皮质椎弓根钉;C组:传统PMMA强化单皮质椎弓根钉;D组:后凸成形PMMA强化椎弓根钉;E组:后凸成形PMMA强化侧翼钉。在MTS试验机上对五种骶骨钉依次进行轴向拔出测试,记录最大拔出力并比较。结果11具标本的平均骨密度为0.71±0.08g/cm2。A组的螺钉拔出力(508N)显著低于其他4种固定组(P<0.05)。B组的螺钉拔出力(685N)与E组(702N)无显著差异(P>0.05),但是,两者的拔出力均显著低于C和D组(P<0.05)。重要的是,D组(986N)的拔出力显著高于C组(846N)。结论在骨质疏松患者的骶骨固定中,双皮质骶骨椎弓根钉较单皮质具有显著的力学优势。骶骨椎弓根钉一旦发生松动,传统的和后凸成形PMMA强化技术均可成为补救手段,并且后凸成形PMMA强化骶骨椎弓根钉可获得最坚强的锚定。Objective To evaluate the biomcchanical effect of kyphoplasty-assisted polymethylmethacrylate （PMMA） augmented technique on the sacral screw fixation strength in osteoporotic sacrum, and guide the use of rigid salvage technique for loosened sacral pedicle screw. Methods 11 fresh osteoporotic cadaveric sacra were used in this study. Following measurement of the bone mineral density （BMD） of each specimen with dual-energy radiograph absorptiometry, two pedicle screws and three salvage techniques with PMMA augmentation were sequentially established and tested on the same sacrum as follows, Group A： unicortieal pediele screw; Group B： bicortical pediele screw; Group C： pediele screw with traditional PMMA augmented technique; Group D： pedicle screw with kyphoplasty-assisted PMMA augmentation; Group E： ala screw with kyphoplasty-assisted PMMA augmentation. Axial pull-out resistance of each screw was sequentially tested on a MTS material testing machine, and the maximum pull-out strengths were measured and compared. Results The average BMD of 11 specimens was 0.71 ±0.08 g/cm^2. Group A （508 N） exhibited significantly lower pull-out strength compared with all the other groups （ P 〈 0. 05 ）. No statistical difference on pull-out strength was detected between Group B （685 N） and E （702 N） （P 〉0.05） ; however, the two techniques exhibited markedly lower pull-out strength than Group C and D （ P 〈 0. 05 ）. Importantly, the pull-out strength in Group D （986 N） was obviously higher than that in Group C （846 N）. Conclusion For sacral screw fixation of osteoporotic patient, bicortical pedicle screw could acquire significantly higher fixation strength than the unieortical. Once the loosening of pedicle screw occurs, the traditional and kyphoplastyassisted PMMA augmentations may serve as a suitable salvage technique. Moreover, the sacral pedicle screw with kyphoplasty-assisted PMMA augmented technique may obtain the strongest anchoring.

关 键 词：腰骶融合 骨质疏松 骶骨钉 骨水泥强化 生物力学 

分 类 号：R683.2[医药卫生—骨科学] R687.3[医药卫生—外科学]