O型臂3D导航与徒手置钉在上颈椎椎弓根螺钉置入中的精确性比较

Accuracy of the pedicle screw insertion in upper cervical spine: a comparison between 3D O-arm based navigation and free-hand technique

目的 ：比较O型臂3D导航下C1、C2椎弓根螺钉置钉与徒手置钉精确性的差异,探讨O型臂导航在上颈椎椎弓根螺钉置钉中的应用价值。方法：纳入我院C1、C2椎弓根螺钉内固定患者62例,分为导航置钉组（A组）与徒手置钉组（B组）。A组：2014年1月~2015年3月,O型臂导航下行C1、C2后路椎弓根螺钉内固定术22例,男15例,女7例,年龄17~58岁（40.8±12.7岁）;B组：2005年3月~2013年12月经徒手置入C1及C2椎弓根螺钉患者40例,男26例,女14例,年龄12~70岁（42.0±15.6岁）。所有患者术后均行颈椎CT平扫,按照Neo等的方法,根据椎弓根螺钉穿破椎弓根皮质的程度将置钉精确性分为四级（0级,螺钉完全处于椎弓根中,没有穿破骨皮质;1级,螺钉穿破皮质〈2mm,或小于螺钉直径的50%;2级,螺钉穿破皮质≥2mm且﹤4mm,或大于螺钉直径的50%但没完全穿出;3级,完全穿出皮质,螺钉处于椎管或椎动脉孔内）,分别评估两组的置钉精确性并比较两组间的差异。结果：A组共置入C1、C2椎弓根螺钉67枚（C1 28枚,C2 39枚）,其中0级60枚（89.6%）,1级7枚（10.4%）,无2级或3级不良置钉;B组共置入C1、C2椎弓根螺钉134枚（C1 64枚,C2 70枚）,其中0级116枚（86.6%）,1级13枚（9.7%）,2级4枚（3.0%）,3级1枚（0.7%）。两组间置钉精确性分级（P=0.49）及0级置钉率（P=0.55）均无统计学差异;A组未发现不良置钉,B组不良置钉发生率为3.7%,但组间无统计学差异（P=0.17）。两组均无置钉相关的血管、神经并发症发生。结论：术中O型臂导航与徒手置钉在上颈椎椎弓根螺钉置钉精确性上并无统计学差异,虽然导航能提供清晰的术中3D图像,但该技术未能完全避免置钉时螺钉轻度穿破骨皮质的发生,仍需提高术者与导航系统间的交互作用,完善操作技术,进一步提高置钉精确性。

Objectives： To compare the accuracy of pedicle screw insertion between three-dimensional（3D）O-arm based navigation and free-hand technique in upper cervical spine, and to explore the advantages of the O-arm based pedicle screw insertion. Methods： Sixty-two patients undergoing the upper cervical pedicle screw insertion in our institution were included and divided into two groups, the navigation group（group A）and free-hand group（group B）. Group A consisted of 22 consecutive patients, including 15 males and 7 fe-males with a mean age of 40.8±12.7 years（17-58 years）, all patients underwent posterior upper cervical pedicle screw instrumentation based on intraoperative 3D navigation by using O-arm system between January 2014 and March 2015. Group B consisted of 40 patients（26 males and 14 females） received both free-hand C1 and C2 pedicle screw insertion from March 2005 to December 2013, all patients had an average age of 42.0 ±15.6years（12-70 years）. All patients undertook postoperative CT scans to assess the accuracy of cervical pedicle screw placement of each group and the differences between two groups were compared. The accuracy of pedicle screw insertions was classified into 4 grades according to Neo′ s classification based on pedicle-wall perforations（grade 0, no perforation of the pedicle; grade 1, perforations 〈2mm, or 〈50% of screw diameter outside the pedicle; grade 2, perforations between ≥2mm and 4mm, or ﹥50% of screw diameter outside the pedicle; grade 3, perforations〉 4mm, or complete perforation）. Results： Group A had 67 upper cervical pedicle screws being inserted（28 C1 pedicle screws and 39 C2 pedicle screws）, 60（89.6%） of them were classified as grade 0, 7（10.4%） were grade 1, no grade 2 or grade 3 was identified. A total of 134 upper cervical pedicle screws were placed in group B（64 C1 pedicle screws and 70 C2 pedicle screws）. 116（86.6%）of them were classified as grade 0, 13（9.7%） as grade 1, 4（3.0%） as grade 2, 1（0.7%） as grade 3. There was no statistical significance of the accuracy distribution of pedicle screw insertion and grade 0 screw placement between 2 groups（P=0.49 and P=0.55, respectively）; moreover, the malposition of pedicle screws was identified in 3.7% screws of free-hand group, which was not found in navigation group, however, no significant difference was identified（P =0.17）. No neurovascular complications related to pedicle screw insertion were noted in both groups. Conclusions： No significant difference of the accuracy in upper cervical pedicle screw insertion between O-arm navigation and free-hand group is found. Even clear intraoperative three-dimensional images can be provided by O-arm navigation, pedicle screw perforation cannot be completely prevented with this technology. Therefore, the interaction between the surgeon and navigation system should be improved and manipulation of O-arm navigation should be optimized to achieve more accuracy during pedicle screw placement.