下颈椎椎板和侧块作为椎弓根置钉角度参考标志的可靠性

Reliability of subaxial vertebral lamina and lateral mass for the orientation of pedicle screw insertion

中文关键词:  下颈椎  椎板  侧块  置钉角度  椎弓根螺钉

英文关键词:Subaxial cervical vertebra  Vertebral lamina  Lateral mass  Direction of pedicle screw insertion  Pedicle screw

中文摘要:

  【摘要】 目的：探讨下颈椎椎板和侧块作为椎弓根置钉角度参考标志的可靠性。方法：完整成人颈椎骨性标本10具，男、女各5具，模拟施行下颈椎椎弓根置钉手术；术前对C3~C7进行螺旋CT扫描多平面重建，确定椎弓根进钉轴，并以椎板和侧块作为椎弓根内倾角和上倾角的参考标志，测量椎弓根进钉轴与同侧椎板的夹角（PL角）及与侧块后表面的夹角（PLM角），术中以相同参考标志和置钉角度置入椎弓根螺钉。术后复查CT并评估椎弓根螺钉置钉的准确率：0级，螺钉完全位于椎弓根内；1级，穿破椎弓根的部分<螺钉直径的25%；2级，螺钉直径的25%~50%穿破椎弓根；3级，螺钉直径>50%穿破椎弓根；2级和3级螺钉为误置。对颈椎标本各节段椎弓根螺钉位置的分级与椎弓根的宽度与高度进行相关性分析。2011年10月~2012年12月，用同样方法对6例患者进行下颈椎椎弓根螺钉置钉手术，评估置钉准确率和并发症情况。结果：10具颈椎标本的下颈椎椎弓根的PL角，C3、C4>C5、C6>C7；PLM角，C3、C4

英文摘要:

  【Abstract】 Objectives: To explore reliability of subaxial vertebral lamina and lateral mass as anatomic landmark for the orientation of pedicle screw insertion. Methods: Pedicle screws were inserted into C3-C7 pedicles on 10 adult cervical vertebral specimens(5 males and 5 females). Vertebral lamina and lateral mass was regarded as anatomic landmark defined as transverse and sagittal angle of pedicle screw insertion respectively. Pedicle-lamina angle(PL angle, the transverse angle) between the central axis of each pedicle and vertebral lamina, and pedicle-lateral mass angle(PLM angle, the sagittal angle) between the central axis and lateral mass were measured preoperatively on computed tomography(CT) images. On the postoperative CT, the grade of pedicle perforation was analyzed(Grade 0 was defined when the entire screw was placed within the cortical bone of the pedicle, grade 1 was defined as less than 25% of the screw diameter violation, grade 2 was defined as 25% to 50% of the screw diameter violation, and grade 3 was defined as more than 50% of the screw diameter violation). Grade 0 and 1 were considered to be the correct position, whereas grade 2 and 3 were considered to be wrong positions.Correlative analysis between the grade of each pedicle screw position and the pedicle width or height was performed. From October 2011 to December 2012, 6 patients underwent pedicle screw insertion on subaxial cervical vertebra. Complications and accuracy of pedicle screw placement were evaluated. Results: Among 10 cervical spine specimens, PL angles of C3-C7 pedicles on axial CT images were C3, C4>C5, C6>C7. PLM angles of C3-C7 pedicles on sagittal CT images were C3, C4