Gantous A, Phillips J H
Department of Otolaryngology, University of Toronto, Ontario, Canada.
Plast Reconstr Surg. 1995 Jun;95(7):1165-9. doi: 10.1097/00006534-199506000-00004.
Screw failure during insertion is not an uncommon problem, especially with the micro and mini fixation systems. In this study, the holding power of 1-, 1.5-, and 2-mm screws was tested at various simulated bone thicknesses of 1, 2, 3, 4, and 5 mm with an increasing pilot hole size. This was done to ascertain the effects of pilot hole size on screw failure and any subsequent tradeoff with respect to decrease in holding power. For the 1-mm screws, there was no statistically significant decrease in holding power of the screws with increasing pilot hole size that ranged from 70 to 85 percent of the external diameter of the screw. For the 1.5-mm screw, a critical pilot hole size was found to be 1.24 mm (82 percent of the screw's external diameter), with no statistically significant decrease in holding power in the 1-, 2-, and 3-mm thickness blocks. For the 2-mm screws, the critical pilot hole size was found to be 1.65 mm (83 percent of the screw's external diameter). A statistically significant decrease in holding power was observed after this drill hole size in all thicknesses. Commercially available systems use drill bits that represent approximately 70 to 75 percent of the external diameter of the screw. Our results show that the pilot hole size for the 1-, 1.5- and 2-mm screws can be increased to 80 to 85 percent of the screw's external diameter without losing significant holding power.(ABSTRACT TRUNCATED AT 250 WORDS)
在螺钉植入过程中出现螺钉失效并非罕见问题，尤其是对于微型和小型固定系统而言。在本研究中，对1毫米、1.5毫米和2毫米的螺钉在1、2、3、4和5毫米的各种模拟骨厚度下，随着导向孔尺寸增大进行了把持力测试。这样做是为了确定导向孔尺寸对螺钉失效的影响以及随后在把持力降低方面的任何权衡。对于1毫米的螺钉，随着导向孔尺寸从螺钉外径的70%增加到85%，螺钉的把持力没有统计学上的显著下降。对于1.5毫米的螺钉，发现临界导向孔尺寸为1.24毫米（螺钉外径的82%），在1毫米、2毫米和3毫米厚度的骨块中，把持力没有统计学上的显著下降。对于2毫米的螺钉，临界导向孔尺寸为1.65毫米（螺钉外径的83%）。在所有厚度下，超过这个钻孔尺寸后，观察到把持力有统计学上的显著下降。市售系统使用的钻头约为螺钉外径的70%至75%。我们的结果表明，1毫米、1.5毫米和2毫米螺钉的导向孔尺寸可以增加到螺钉外径的80%至85%，而不会显著损失把持力。（摘要截选至250字）
