BACKGROUND: Spinal lamina reimplantation assisted hollow screw laminoplasty has achieved good clinical efficacy. The search literature found that there is no research at home and abroad on the biomechanical properties of unilateral and bilateral hollow screw fixation. OBJECTIVE: To evaluate the biomechanical property of different fixation with hollow screws in artificial and goat vertebrate laminoplasty. METHODS: A laminoplasty was conducted by using hollow screws. Based on the artificial vertebrate laminoplasty model, new models were generated by simulating unilateral screws fixation with a depth of screw insertion 5 mm (A group), unilateral screw fixation with a depth of screw insertion 8 mm (B group) and bilateral screw fixation with a depth of screw insertion 5 mm (C group). Based on the goat vertebrate laminoplasty model, new models were generated by simulating unilateral screws fixation (A group) and bilateral screw fixation (B group). The pull-out strength and static pressure were tested in the biomechanical testing machine with a sensor. RESULTS AND CONCLUSION: (1) In the artificial vertebrate model, the average pull-out strength of the group B was stronger than that of the groups A and C (P < 0.01); the average pull-out strength of the group A was stronger than that of group C (P < 0.01), the difference was statistically significant (P < 0.05). However, the average static compression of the group A and group B was similar; the average static compression of the group C was lower than that of the groups A and B, and the difference was statistically significant (P < 0.01). (2) In the goat vertebrate model, the average pull-out strength and static compression of the group A were stronger than that of the group B, and the difference was statistically significant (P < 0.05). (3) Results suggest that unilateral screw fixation in the artificial and goat vertebrate laminoplasty can provide sufficient pull-out strength and static compression, and the biomechanical strength is positively related to the depth of the screw.%背景:脊柱椎板回植辅助空心钉椎管成形已取得良好临床疗效;检索文献发现目前国内外尚无关于单侧与双侧空心钉固定椎管成形生物力学特性的研究实验.目的:测试人工椎体及山羊椎体椎管成形结合螺钉不同内固定方式的生物力学性质.方法:人工仿形骨常规棘突椎板复合体回植辅助螺钉原位回植内固定实验分成3组,A 组单枚螺钉置入深度5 mm,B组单枚螺钉置入深度8 mm,C组双侧分别置入螺钉5 mm.成年山羊胸椎标本椎管成形结合螺钉内固定实验分成2组,A组为单枚螺钉固定加压组,B组为双侧置入螺钉组.在生物力学试验机上通过传感器测出固定螺钉的最大拔出力及对棘突的静态压缩力.结果与结论:①在人工仿形骨的拔出测试实验中,单钉置入8 mm的拔出力值约为单钉置入5 mm失效力值的2倍(P < 0.01);而置入双钉5 mm的拔出力值远低于单侧置入8 mm的拔出力值(P < 0.01),且低于单钉置入5 mm的拔出力值(P < 0.05).静态压缩测试实验中,2个单钉置入组的结果相近,差异无显著性意义;双钉置入的静态压缩力值低于2个组单钉置入组,且差异有显著性意义(P < 0.01);②成年羊骨单钉置入的拔出力值及静态压缩力均高于双钉置入组,且差异有显著性意义(P < 0.05);③结果表明,与双钉置入相比,脊柱椎板回植结合单枚螺钉内固定加压可以提供更大的生物力学稳定性,其强度与螺钉置入深度呈正相关.
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