Weinstein J N, Oster D M, Park J B, Park S H, Loening S
Department of Orthopaedic Surgery, University of Iowa, Iowa City 52242.
Clin Orthop Relat Res. 1988 Oct(235):261-7.
The extracorporeal shock wave lithotriptor (ECSWL) is a machine that generates shock waves that transfer energy through biologic materials. This study focused the wave at a composite bone-cement (polymethylmethacrylate) interface and evaluated the effects both quantitatively and qualitatively. Six matched sets of dog femora were selected. The intramedullary canals were packed uniformly with cement. One of the set was randomly selected for treatment with impulses while the other served as the control. The bone was then sectioned transversely into discs, and scanning electron microscopy and mechanical push-out studies were performed. The results indicated that the ECSWL does have a loosening effect on the bone-cement interface. Using a paired Student's t-test, the shear strength was significantly less in the treated group than in the control (p less than 0.003). Microscopically, the treated specimens revealed relative sparing of the surrounding bone. At the bone-cement interface, however, microfractures, loose bodies, and widening were seen. Revision total arthroplasty has a significant morbidity, which can be partially attributed to cement extraction. The results of this study indicate that the ECSWL may be a useful adjunct in revision surgery by facilitating the extraction of polymethylmethacrylate and thereby reducing the morbidity.
体外冲击波碎石机（ECSWL）是一种能产生冲击波并通过生物材料传递能量的机器。本研究将冲击波聚焦于复合骨水泥（聚甲基丙烯酸甲酯）界面，并对其效果进行了定量和定性评估。选取了六组匹配的犬股骨。髓腔内均匀填充水泥。随机选择其中一组用脉冲进行治疗，另一组作为对照。然后将骨头横向切成薄片，进行扫描电子显微镜检查和机械推出试验。结果表明，体外冲击波碎石术确实对骨水泥界面有松动作用。使用配对t检验，治疗组的剪切强度明显低于对照组（p<0.003）。在显微镜下，治疗后的标本显示周围骨相对保存完好。然而，在骨水泥界面处，可见微骨折、松动体和增宽。翻修全关节置换术有显著的发病率，这部分可归因于骨水泥取出。本研究结果表明，体外冲击波碎石术可能是翻修手术中的一种有用辅助手段，通过促进聚甲基丙烯酸甲酯的取出，从而降低发病率。
