BACKGROUND Aim of this biomechanical study was to investigate the anchorage of pedicle screws in osteoporotic vertebrae using two different preparation techniques (probe versus drill-assisted). METHODS Twelve thoracic vertebrae were used for the study. The right and left pedicles of the vertebra were prepared with a thoracic probe or a 3.2 mm drill bit and divided into two groups. A standard titanium (diameter: 5.5 mm, length: 45 mm) pedicle screw was then inserted. All pedicle screws were initially loaded with -25 N to +25 N in the cranio-caudal direction. The load was increased by 5 N every 500 cycles up to a maximum load of 10,000 cycles. Loosening was defined as a displacement of the pedicle screw head of >5 mm. The two groups were compared in terms of maximum number of cycles and maximum force until loosening. FINDINGS The pedicle screws prepared with the thoracic probe failed on average after 3819 cycles (SD 3281) and the pedicle screws prepared with the 3.2 mm drill after 3335 cycles (SD 3477). There was no significant difference between the two preparation techniques (P = .797). With regard to the maximum force until loosening, there was also no significant difference between the two techniques (thoracic probe: 61 N (SD 33), 3.2 mm drill bit: 56 N (SD 34), P = .791). INTERPRETATION Preparation of the pedicle screw hole either with a probe or drill bit doesn't seem to have an influence on pedicle screw loosening rates in the osteoporotic spine.

中文翻译：

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探针与钻头：两种不同的椎弓根准备技术在人体尸体骨质疏松性脊柱椎弓根螺钉固定中的生物力学评估。

背景技术该生物力学研究的目的是使用两种不同的制备技术（探针与钻头辅助）研究椎弓根螺钉在骨质疏松椎骨中的锚固。方法采用十二枚胸椎作为研究对象。用胸部探针或3.2 mm钻头准备椎骨的左右椎弓根，分为两组。然后插入标准钛（直径：5.5 mm，长度：45 mm）椎弓根螺钉。最初，所有椎弓根螺钉在颅尾方向上均承受-25 N至+25 N的载荷。每500个循环将负载增加5 N，直到10,000个循环的最大负载。松动定义为椎弓根螺钉头的位移> 5 mm。根据最大循环数和最大力直到松动比较两组。结果发现，经3819次循环（SD 3281）后，用胸腔探针准备的椎弓根螺钉平均失效；经3335次循环（SD 3477）后，由3.2 mm钻头准备的椎弓根螺钉平均失效。两种制备技术之间没有显着差异（P = .797）。关于直到松开的最大力，两种技术之间也没有显着差异（胸廓探头：61 N（SD 33），3.2 mm钻头：56 N（SD 34），P = .791）。解释用探针或钻头制备椎弓根螺钉孔似乎对骨质疏松性脊柱椎弓根螺钉的松动率没有影响。两种制备技术之间没有显着差异（P = .797）。关于直到松开的最大力，两种技术之间也没有显着差异（胸廓探头：61 N（SD 33），3.2 mm钻头：56 N（SD 34），P = .791）。解释用探针或钻头制备椎弓根螺钉孔似乎对骨质疏松性脊柱椎弓根螺钉的松动率没有影响。两种制备技术之间没有显着差异（P = .797）。关于直到松开的最大力，两种技术之间也没有显着差异（胸廓探头：61 N（SD 33），3.2 mm钻头：56 N（SD 34），P = .791）。解释用探针或钻头制备椎弓根螺钉孔似乎对骨质疏松性脊柱椎弓根螺钉的松动率没有影响。