虚拟手术系统支持下置入寰椎侧块螺钉的实验研究

目的:建立虚拟手术系统支持下经寰椎侧块内固定的标准体系及操作流程,探讨在其支持下置入寰椎侧块螺钉的可行性及准确性。方法:选取8例成年无破损和畸形的寰椎(C1)防腐头颈标本,CT扫描后,数据导入虚拟手术系统进行三维重建和螺旋CT多平面重建(MPR),测量寰椎侧块数据;选择侧块与后弓根部下方交界区和横突孔的内侧缘与寰椎后弓内侧壁中点为进钉点,分别测量横突孔的内侧缘与寰椎后弓内侧壁的距离(L1),进钉点与侧块前缘最高点的距离(L2),进钉点与侧块前缘的垂直距离(L3),进钉点的垂线与寰椎侧块上缘切线的角度(α),进钉点垂线与横突孔内侧缘切线的角度(β),进钉点垂线与侧块内侧缘切线的角度(γ),并计算内斜角度[δ=(β+γ)/2-β]。左右两侧均测量3次,取其均值,进行统计学分析。根据虚拟手术系统测量结果,在标本上模拟手术置入寰椎侧块螺钉,然后虚拟手术系统进行重建,测量置钉准确性。结果:建立了虚拟手术系统手术流程,虚拟手术系统测量寰椎侧块相关参数L1左侧为9.82±0.76mm,右侧为9.16±0.85mm;L2左侧为21.76±1.36mm,右侧为21.50±1.02mm;L3左侧为17.78±1.67mm,右侧为18.22±1.60mm;α左侧为36.78°±1.23°,右侧为35.78°±2.40°;β左侧为18.84°±1.80°,右侧为18.40°±1.71°;γ左侧为31.49°±0.60°,右侧为30.46°±1.56°;δ左侧为6.32°±1.08°,右侧为6.25°±1.11°;经统计学分析,左右侧测量值均无统计学差异(P>0.05)。尸体标本置钉16枚,全部位于侧块内,未伤及毗邻组织。结论:虚拟手术系统支持下置入寰枢椎侧块螺钉可行且准确性高。

Atlas lateral mass screw insertion under virtual surgical system

Objectives: To establish a standard system and a standard operational process of atlas lateral mass screw insertion assisted by virtual surgical system and to investigate its feasibility and accuracy.Methods: CT scan were performed on eight specimens(bilateral) of atlas(C1) without damage or bony malformation,then the data were transferred into the virtual surgery system for three-dimensional reconstruction and multiple planar reformation(MPR) so as to measure the C1 lateral mass,the junctional zone of lateral mass and underside of posterior arch pedical and midpoint of inner border of transverse foramen and inner wall of the posterior arch of atlas was selected as screw insertion point.The following parameters were measured: the distance between the inner border of transverse foramen and the inner wall of posterior arch of atlas(L1),the distance between screw insertion point and the highest point of front border of lateral mass(L2),the vertical distance between screw insertion point and the highest point of front border of lateral mass(L3),the angle between perpendicular of screw insertion point and tangent of up border of lateral mass(α),the angle between perpendicular of screw insertion point and tangent of inner border of transverse foramen(β),the angle between perpendicular of screw insertion point(γ) and tangent of inner border of lateral mass[δ:(β+γ)/2-β].The measurements were performed on left and right sides and the mean values were taken for statistical analysis.Based on the measurements,the procedure of atlas lateral mass screw insertion was simulated on specimens,the virtual surgical system reconstructed,and the accuracy of insertion finally evaluated.Results: A virtual surgical system for operational process was established.The relative parameters of atlas lateral mass were as follows,L1: the left side was 9.82±0.76mm,the right side was 9.16±0.85mm;L2: the left side was 21.76±1.36mm,the right side was 21.50±1.02mm;L3: the left side was 17.78±1.67mm,the right side was 18.22±1.60mm;α: the left side was 36.78°±1.23°,the right side was 35.78°±2.40°;β: the left side was 18.84°±1.80°,the right side was 18.40°±1.71°;γ: the left side was 31.49°±0.60°,the right side was 30.46°±1.56°;δ: the left side was 6.32°±1.08°,the right side was 6.25°±1.11°.All data from left and right side by virtual surgery system showed no statistical difference(P>0.05).All sixteen screws located in lateral mass accurately,with no penetration into surrounding structure.Conclusions: Atlantoaxial lateral mass screw insertion assisted by the virtual surgical system is feasible and accurate.