Abstract:Objective To identify the anatomical feasibility of screwplate system adopted in posterior arch of atlas,provide a reference for clinical applications.Methods A total of 60 3D CT and 30 dry atlas specimens were used to measure anatomical data.The parameters included anterior to posterior thickness and superior to inferior height of the posterior ring of C1 at the midline as well as at 5mm,10mm,15mm lateral to the midline,angle of posterior arch,internal semi-distance of the outside screw(from midline to outer edge of screw in inner side),distance from the planned cross nail entry point to the edge of outer screw which called supposed biggest length of cross screw(where screws completely located in the medullary cavity without touching the outer screw).The data gained from CTs and specimens were then compared.The anatomy of the atlas was analyzed and the design of internal fixation screw-plate system was performed.Results The height of the center of posterior nodule was (9.48±0.95)mm,and the respective thickness was (7.80±1.60)mm,the angle of posterior arch was (130.70±12.31) °,the biggest length of cross screw was (13.67±0.53)mm and the supposed internal semi-distance of the outside screw was (10.51±0.95) mm tested in CTs. The respective parameters from specimens were (9.97±2.18)mm,(7.44±1.32)mm,(135.07±9.59)°,(14.17±0.54)mm and (11.03±1.07)mm.No statistical difference was found between data of the left side and the right side,whereas the outcomes including the biggest length of cross screw and the supposed internal semi-distance of the outside screw from CTs were smaller than those from specimens with statistical difference.Conclusion Data measured from CT provides a reference in clinical practice but can not present anatomical structure precisely.It is feasible and safe for posterior arch screw-plate fixation system in anatomy which may be an new alternative of atlantoaxial fixation.
[1]Syre P,Petrov D,Malhotra NR.Management of upper cervical spine injuries a review[J].J Neurosurg Sci,2013,57(3):219-240.
[2]Richard J.Bransford M,Timothy B,et al.Upper cervical spine trauma[J].J Am Acad Orthop Surg,2014,22(11):718-729.
[3]Huang D,Hao D,He B,et al.Posterior atlantoaxial fixation:a review of all techniques[J].Spine J,2015,15(10):2271-2281.
[4]倪斌,郭翔.对后路寰枢椎固定技术的评价及选择策略[J].中国脊柱脊髓杂志,2013,23(5):392-393.
[5]马乐群,镇万新,徐亮,等.Apofix椎板夹内固定在寰枢椎不稳治疗中的应用[J].中华骨科杂志,2005,25(10):28-31.
[6]Menendez JA,Wright NM.Techniques of posterior C1 to C2 stabilization[J].Neurosurgery,2007,60(1):103-111.
[7]刘海兵,王文军.寰枢椎后路内固定术的研究进展[J].中国现代医药杂志,2009,11(4):128-131.
[8]Lapsiwala SB,Anderson PA,Oza A,et al.Biomechanical comparison of four C1 to C2 rigid fixative techniques:anterior transarticular,posterior transarticular,C1 to C2 pedicle,and C1 to C2 intralaminar screws[J].Neurosurgery,2006,58(3):516-521.
[9]郭晓辉,刘兰泽,逯强,等.寰椎后弓螺钉在寰枢椎后路固定融合手术中的应用[J].中国脊柱脊髓杂志,2015(12):1129-1131.
[10]马向阳.寰椎后路螺钉固定技术[J].中国骨科临床与基础研究杂志,2015,7(3):177-182.
[11]Jurgen Harms,Melcher R P.Posterior C1 to C2 fusion with polyaxial screw and rod fixation[J].Spine,2001,26(22):2467-2471.
[12]Christensen DM,Eastlack RK,Lynch JJ,et al.C1 anatomy and dimensions relative to lateral mass screw placement[J].Spine,2007,32(8):844-848.
[13]朱海波,贾连顺,孙启全,等.寰椎测量及临床意义[J].解剖学杂志,1997,20(6):517-520.
[14]金国鑫,王欢,李雷,等.寰椎后弓螺钉交叉固定的解剖学研究[J].中华骨科杂志,2012,32(1):65-69.
[15]Guo-Xin Jin,Huan Wang,Lei Li,et al.C1 posterior arch crossing screw fixation for atlantoaxial joint instability[J].Spine,2013,38(22):1397-1404.
[16]Guo-Xin Jin,Huan Wang,Lei Li.Unilateral C1 posterior arch screws and C2 laminar screws combined with a 1-side C1~2pedicle screw system as salvage fixation for atlantoaxial instability[J].J Neurosurg Spine,2016,24(2):315-320.
[17]Kelly BP,Glaser JA,Diangelo DJ.Biomechanical comparison of a novel C1 posterior locking plate with the harms technique in A C1 to C2 fixation model[J].Spine,2008,33(24):920-925.
[18]Eb K.Surgical approaches to the neck[M]//Cervical spine and upper extremity.London:Saunder,1966:9.
[19]Meyer D,Meyer F,Kretschmer T,et al.Translaminar screws of the axis-an alternative technique for rigid screw fixation in upper cervical spine instability[J].Neurosurgical Review,2012,35(2):255-261.
[20]周凤金,倪斌,谢宁,等.个体化后路寰枢椎融合内固定治疗寰枢椎不稳[J].脊柱骨科杂志,2014,12(3):143-146.