经口咽前路寰枢椎复位钢板固定螺钉拔出强度的实验研究

Experimental study of screw pull-out strength of anterior transoralpharyngeal atlantoaxial reduction plate

目的:对经口咽前路寰枢椎复位钢板(transoralpharyngeal adantoaxial reduction plate,TARP)螺钉进行固定螺钉拔出力实验,探讨TARP螺钉固定的可行性.方法:6例C1～C3椎体新鲜标本,左右双侧均行螺钉固定,寰椎螺钉固定于侧块,枢椎和C3椎体螺钉固定于椎体.在生物力学实验机上通过传感器测定TARP寰椎和枢椎固定螺钉的最大拔出力、钉道长度,并将结果同C3椎体螺钉固定进行比较.结果:寰椎与枢椎、寰椎与C3椎体的固定螺钉的最大拔出力之间均有显著性差异,枢椎和C3椎体最大拔出力之间无显著性差异.寰椎与枢椎、寰椎与C3椎体的钉道长度之间均有显著性差异,枢椎和C3椎体钉道长度之间无显著性差异.C1～C3的最大拔出力与钉道长度呈显著正相关(r=0.810).结论:TARP螺钉固定是比较安全的,固定时一般采用钻孔后丝攻攻破寰椎、枢椎和C3椎体前表面较硬的骨质后用单皮质螺钉固定.钉道长度(即进钉深度)是影响拔出力的重要因素.

Objective:To evaluate the screw pull-out strength of transoralpharyngeal atlantoaxial reduction plate(TARP).Method:Six fresh C1～C3 spine specimens(totally 12 cases including both sides) were designed to compare screw pull-out strength and screw path length of C1 and C2 with that of controlled C3.C1 screw was implanted into the lateral mass and C2～C3 screws were anchored into the vertebrae.Result:There was statistically significant difference between screw pull-out strength,screw path length of C1 and those of C2/C3.No statistically significant difference was observed between screw pull-out strength and path length of C2 and C3.Screw pull-out strength was positively correlative to path length(r=0.810).Conclusion:Experimentally,anterior C1～C2 screw placement of TARP is strong and safe.It is necessary to tap for TARP operation.C1 and C2 screws should be implanted unicortically.Screw path length is one of the important factors of influencing screw pull-out strength.