寰椎椎弓根螺钉进钉通道的选择

Selection of the screw fixation path in atlas via pedicle of vertebral arch

目的：探讨不同寰椎椎弓根通道置钉的可行性及安全范围。方法：选取成年人共58例（116侧）寰椎或寰枢椎的MSCT扫描资料进行分析：设定3个进钉通道，测量寰椎高度、宽度、进钉长度及进钉方向等解剖径线。结果：寰椎椎弓根左右两侧各指标差异无统计学意义（ P＞0．05）。58例寰椎椎弓根矢状面上的宽度与椎弓根宽度的平均值为8．21和9．59 mm，其中有3侧椎弓根矢状面上的宽度小于5．5 mm。钉道1、2、3的椎弓根高度的平均值分别为4．57、4．55、4．51 mm，椎弓根高度小于3．5 mm所占的比例分别为11．21％（6/58）、12．06％（7/58）、12．06％（7/58）。钉道3的平均内倾角为21．27＆#176;。钉道1、2、3的头倾夹角平均值分别为17．88＆#176;、18．27＆#176;、15．24＆#176;，钉道长度的平均值分别为29．02、27．69、28．55 mm。结论：寰椎椎弓根进钉首选钉道2、3之间，内倾角度为0＆#176;～10＆#176;，进钉长度27．5 mm。

Aim：To evaluate the feasibility and the safety range of the pedicle screw placement in atlas by different channels and choose the best entry channel .Methods： Fifty-eight （ 116 sides ） adults of atlas or atlantoaxial lesion were randomly selected ,who had a multi-slice spiral CT screening .Three screw fixation pathways in atlas via posterior pedicle of vertebral arch were set up , and the parameters of atlas pedicle including the height ,width,lenghth and direction of screw were measured .Results：The differences of anatomic measurements of atlas pedicles between the two sides were not statis -tically significant （P＆gt;0.05）.All the mean width of the atlas pedicle in sagittal direction and the direction of pedicle was 8.21 and 9.59 mm, respectively,and 3 sides with the width less than 5.5 mm.The mean height （H1,H2,H3） of the atlas pedicle of vertebral arch was 4.57, 4.55 and 4.51 mm,among which, the height less than 3.5 mm accounted for 11.21%（6/58）,12.06%（7/58） and 12.06%（7/58）.The median inside oblique angle of channel 3 of atlas pedicle screw fixation was 21.27°, and the median superior inclination angles of 3 channels were 17.88°,18.27°;and 15.24°.The mean path length（D1E1,D2E2,D3E3） atlas pedicle were 29.02,27.69 and 28.55 mm.Conclusion： It is more safe to implant screws between channel 2 and channel 3, with the inside oblique angle between 0°-10°,and the mean path length of 27.5 mm.