脊柱虚拟手术系统测量下颈椎椎弓根固定相关参数精确性的实验研究

ACCURACY OF RELATED PARAMETERS TO SCREW PLACEMENT IN LOWER CERVICAL PEDICLE MEASURED BY SPINAL VIRTUAL SURGERY SYSTEM

目的通过与多层螺旋CT(multi-spiral CT,MSCT)工作站测量参数进行比较,评价自主研发的脊柱虚拟手术系统(spinal virtual surgery system,SVSS)三维重建技术测量数据的精确性。方法取7具成年男性颈椎标本经MSCT扫描后,分别将信息传送至MSCT工作站及SVSS,结合下颈椎椎弓根植钉参数要求,采用两系统进行容积重建和多平面重组,重建后测量椎弓根10个参数。然后应用SPSS11.0统计软件包对两系统测量数据进行对比分析。2009年6月-2010年3月,临床应用SVSS辅助下颈椎椎弓根固定手术6例。结果 SVSS测量时发现7具标本中1个椎弓根缺失(C3)、4个椎弓根冠状位直径<3 mm(C4 1个、C5 2个、C6 1个),与MSCT工作站测量结果一致。统计学分析显示,除C3左侧椎弓根皮质骨高度、C4两侧椎弓根皮质骨宽度、C4右侧椎弓根松质骨宽度、C6左侧椎弓根入点至侧块边缘切距、C3两侧椎弓根入点至下关节突下缘距离、C3两侧及C5左侧椎弓根入点至椎体前缘矢状位距离,以及C3两侧、C5左侧、C6右侧椎弓根入点至椎体前缘轴位距离共计14组数据,两系统比较差异有统计学意义(P<0.05)外;其余数据差异均无统计学意义(P>0.05)。临床应用6例共植钉34枚,术后MSCT复查发现30枚(88.24%)完全位于椎弓根内,4枚(11.76%)穿破。参照Richter等的分级标准,1级穿破2枚(5.88%),2级穿破2枚(5.88%),无3级穿破发生。结论 SVSS与MSCT工作站测量数据的准确性基本相同。

Objective To evaluate the accuracy of the related parameters measured by spinal virtual surgery system （SVSS） three-dimensional （3D） techniques by comparing with the parameters measured by multi-spiral CT （MSCT） workstation. Methods Seven vertebrae specimens of adult men were scanned with MSCT, and the messages were sent to MSCT workstation and SVSS. The 3D image of spine was reconstructed by using volume rendering and multi-planar reformation; based on the parameter requirement of lower cervical pedicle fixation, 10 related parameters were measured. Then SPSS11.0 analyzer software was used to analyze the parameters measured by 2 systems. Between June 2009 and March 2010, 6 patients who received screw insertion in lower cervical spines were given MSCT scanning, then the messages were sent to SVSS 3D reconstruction to evaluate the situation and to collect the parameters of pedicle screw insertion. Results SVSS measurement showed that 1 pedicle was clausura （C3） and the diameters of 4 pedicles in coronal view were lee than 3 mm （C4 in 1, C5 in 2, C6 in 1）, which did not fit for screw insertion; the results were similar to those by MSCT measurement. A total of 66 lower cervical pedicle were measured successfully. Significant differences were found in 14 parameters as follows between 2 systems （P 〈 0.05）： the left pedicle height of C3, the both sides pedicle width of C4, the right pedicle spongy width of C4, the left X-direction entrance of C6, the both sides Y-direction entrance of C3, total pedicle length of sagittal view in both sides pedicle of C3 and the left pedicle of C5, total pedicle length of axial view in C3 pedicles, the left pedicle of C5, and the right pedicle of C6. There was no significant difference in the other parameters （P 〉 0.05）. In 6 cl inical cases, 34 screws were inserted, the postoperative MSCT scanning showed that 30 screws were placed successfully. The rate of accuracy was 88.24%. According to the Richter’s perforation classification, perforation at grade I and at grade II occurred in 2 cases （5.88%）, respectively. Conclusion The accuracy of the parameters measured by SVSS is similar to that by MSCT.