Abstract：Objective: To explore the direction of pedicle screw placement for atlas pedicle screw placement through anatomic measurement of atlas specimens and provide theoretical guidance for accurate placement of atlas pedicle screws. Methods: 20 healthy complete atlas specimens were anatomically measured, accurate nail entry points were selected, a constant nail reference system was found, and the angle relationship between the screw channel and the selected reference system was measured to determine the related parameters of the pedicle screw point and angle of the atlas. Results: the width and the height of posterior arch at the thinnest part of the vertebral artery groove; the distance from entrance point of screw to median plane S1=(21.2±3.5)mm; the whole length screw path AB=(26.1±4.4)mm;the distance between the internal and external margin of dorsal of below lateral mass of atlas S2=(11.1±1.1)mm (5) atlas horizontal angle (X) are(10.9±5.2)°; vertical angle (Y) were(4.1±0.7)°. Conclusion: The distance from the midpoint of the internal and external margins of the lateral mass of the atlas to the posterior arch is from the vertical distance from the bottom of the vertebral arch to the most thin part of the arch. 2mm is the insertion point of the screw. The lateral angle is 6 to 16 degrees, and the longitudinal angle is 3 to 5 degrees. It is safe, objective and reliable to select screws with a diameter of 3.5mm and 21.7mm to 30.5mm.
[1] He B,Yan L,Xu Z,et al. Prospective,self-controlled,comparative study of trans-posterior arch lateral mass screw fixation and lateral mass screw fixation of the atlas in the treatment of atlantoaxial instability[J].Spinal Disord Tech ,2013. [2] Resnick DK,Benzel EC. C1-C2 pedicle screw fixation with rigid cantilever beam construct:case report and technical note[J].Neurosurgery,2002,50(2):426~428. [3] Visocchi M,Trevisi G,Iacopino DG,et al. Odontoid process and clival regeneration with Chiari malformation worsening after transoral decompression :an unexpected and previously unreported cause of"accordion phenomenon"[J]. Eur Spine,2015,24(Suppl 4):S564~568. [4] Wu AM,Wang XY,Zhou F,et al. Percutaneous atlantoaxial anterior transarticular screw fixation combined with mini-open posterior C1/2 wire fusion for patients with a high-riding vertebral artery[J].Spinal Cord Med,2016,39(2):234~239. [5] 谭明生,张光铂,李子荣,等.寰椎测量及其经后弓侧块螺钉固定通道的研究[J].中国脊柱脊髓杂志,2002,12(1):5~8. [6] 马向阳,钟世镇,刘景发,等.寰椎椎弓根螺钉进钉点的解剖定位研究[J].骨与关节损伤杂志,2003,18(10):683~685. [7] 胡勇,袁振山,董伟鑫,等.个性化3D打印“定点-定向”双导板辅助寰枢椎后路椎弓根螺钉置钉技术的安全性和准确性[J].中华创伤杂志,2016,32(1):27~34.
2018, Vol. 24 
冀公网安备13080202000677号