尽管椎弓根螺钉设计和手术技术取得了进步,插入椎弓根螺钉的标准步骤仍然需要遵循一套固定程序。第一步,被称为建立一个导向孔,也称为预钻孔,对于确保螺钉插入精度至关重要。在不同的手术方法中,例如微创或传统手术,创建导向孔的方法各不相同,导致不同的导孔轮廓,包括大小和形状的变化。这项研究的目的是评估与各种手术方法相对应的不同导向孔轮廓的生物力学特性。密度为0.16g/cc的市售合成L4椎骨被用作人骨的替代品。使用3.0mm圆柱形骨活检针创建四个不同的导向孔轮廓,3.6mm圆柱钻,3.2-5.0毫米锥形钻头,和3.2-5.0毫米锥形刮匙,用于模拟各种微创和传统脊柱手术。两种常用的螺钉形状,即,圆柱形和圆锥形,被选中。试样制备后,使用材料试验机进行螺钉拔出试验,并应用统计分析来比较每种配置的平均最大拔出强度。锥形和圆柱形螺钉在这四个导向孔配置中显示出类似的趋势,平均最大拔出强度从高到低排序如下:3.0毫米圆柱形活检针,3.6mm圆柱钻头,3.2-5.0mm锥形刮匙,和3.2-5.0毫米锥形钻头。在四种不同的导向孔配置中的三种中,锥形螺钉通常表现出比圆柱形螺钉更大的平均最大拔出强度。在带有锥形导向孔的组中,用3.2-5.0毫米钻头和3.2-5.0毫米刮匙创建,两个锥形螺钉的平均最大拔出强度均大于圆柱形螺钉。这项研究的优势在于综合比较了临床手术中常用的各种导向孔轮廓对螺钉固定稳定性的影响,文献中很少报道的话题。我们的结果表明,与传统手术相比,使用图像引导技术为微创手术创建的导向孔具有更高的拔出强度。因此,当预计螺钉植入困难或需要更坚固的螺钉固定时,我们建议优先考虑微创手术.当选择传统手术时,图像引导方法可以帮助建立更小的导向孔和增加螺钉固定强度。
Despite advancements in pedicle screw design and surgical techniques, the standard steps for inserting pedicle screws still need to follow a set of fixed procedures. The first step, known as establishing a pilot hole, also referred to as a pre-drilled hole, is crucial for ensuring screw insertion accuracy. In different surgical approaches, such as minimally invasive or traditional surgery, the method of creating pilot holes varies, resulting in different pilot hole profiles, including variations in size and shape. The aim of this study is to evaluate the biomechanical properties of different pilot hole profiles corresponding to various surgical approaches. Commercially available synthetic L4 vertebrae with a density of 0.16 g/cc were utilized as substitutes for human bone. Four different pilot hole profiles were created using a 3.0 mm cylindrical bone biopsy needle, 3.6 mm cylindrical drill, 3.2-5.0 mm conical drill, and 3.2-5.0 mm conical curette for simulating various minimally invasive and traditional spinal surgeries. Two frequently employed screw shapes, namely, cylindrical and conical, were selected. Following specimen preparation, screw pullout tests were performed using a material test machine, and statistical analysis was applied to compare the mean maximal pullout strength of each configuration. Conical and cylindrical screws in these four pilot hole configurations showed similar trends, with the mean maximal pullout strength ranking from high to low as follows: 3.0 mm cylindrical biopsy needle, 3.6 mm cylindrical drill bit, 3.2-5.0 mm conical curette, and 3.2-5.0 mm conical drill bit. Conical screws generally exhibited a greater mean maximal pullout strength than cylindrical screws in three of the four different pilot hole configurations. In the groups with conical pilot holes, created with a 3.2-5.0 mm drill bit and 3.2-5.0 mm curette, both conical screws exhibited a greater mean maximal pullout strength than did cylindrical screws. The strength of this study lies in its comprehensive comparison of the impact of various pilot hole profiles commonly used in clinical procedures on screw fixation stability, a topic rarely reported in the literature. Our results demonstrated that pilot holes created for minimally invasive surgery using image-guided techniques exhibit superior pullout strength compared to those utilized in traditional surgery. Therefore, we recommend prioritizing minimally invasive surgery when screw implantation is anticipated to be difficult or there is a specific need for stronger screw fixation. When opting for traditional surgery, image-guided methods may help establish smaller pilot holes and increase screw fixation strength.