【作者】 谢文贵；

【导师】 聂林；

【作者基本信息】 山东大学 ， 外科学（专业学位）， 2013， 硕士

【摘要】 目的寰椎结构特殊,由前弓、后弓以及两侧块和横突构成骨环,没有椎体和棘突,经典解剖学没有椎弓根的结构,大量解剖观察发现寰椎后弓与侧块的连接部分在结构和力学上类似于其他脊椎的椎弓根,解剖与影像测量显示寰椎侧块螺钉可以经后弓经过椎弓根进行固定,称之为寰椎椎弓根螺钉。测量数据显示解剖与影像测量数据一致,可以应用影像学测量指导手术中椎弓根螺钉的置入。寰椎椎弓根螺钉成功置入的关键之一在于进钉点和进钉角度的把握,本研究旨在利用寰椎横断面CT测量建立寰椎椎弓根螺钉安全置钉区域及相应的进钉角度并指导临床手术操作。方法随机选取38例就诊患者的寰椎螺旋CT薄层扫描和三维重建。置钉空间定义为寰椎横断面上进钉通道与横突孔内缘的切线、与椎管外缘的切线这两条平行线间的距离。要安全通过直径3.5mm螺丝钉,寰椎椎弓根螺钉的置钉空间至少5mm。以寰椎椎管外缘与横突孔内缘的最小距离为椎弓根宽度,以此线段的垂直平分线与寰椎后弓的交点为安全置钉区域的外侧界,若此交点在过横突孔内缘的寰椎中线的平行线和后弓交点以外,则以后者为外界。以置钉空间为5mm时螺钉通道中轴线与寰椎后弓交点为内侧界,若此交点落在过寰椎椎管外缘的寰椎中线的平行线和后弓的交点的内侧则以后者为内侧界。测量寰椎后结节与安全置钉区域内、外界点的距离,安全置钉区域内、外侧界点间的距离和相应的进钉角度、进钉通道长度以及椎弓根的宽度。以术前螺旋CT测量确定安全置钉区域的方法,应用管道疏通法对7例患者行寰椎椎弓根螺钉内固定。结果CT测量：椎弓根宽度为(9.15±2.57)mm,可以安全容纳3.5mm螺钉,安全置钉区域：在寰椎后弓距后结节距离(18.35±2.86)mm～(25.26±1.76)mm,进钉角度范围为外倾(9.09±7.45)°～内倾(18.72±17.42)°,钉道长度在(26.20±2.69)mm～(27.04±2.51)mm。安全置钉区域宽度达(6.914±7.66)mm,横断面倾斜角度范围达到(27.81±10.32)。。但存在个体差异。7例患者手术时间90～120min,术中出血60～300ml,无椎动脉、神经根及脊髓损伤。术后行颈椎正侧位X线片及颈椎螺旋CT检查显示14枚椎弓根螺钉位置理想,均位于术前测量安全置钉区域内,无穿破椎弓根骨皮质现象。术后随访6～12月无内固定松动及断裂现象。7例患者植骨均获骨性融合。结论寰椎椎弓根螺钉存在安全置钉区域,在安全置钉区域内可根据进钉点不同相应的内倾或外倾置钉。详尽的术前影像测量,确定安全置钉区域,个体化置钉是手术成功的关键。更多还原

【Abstract】 Objective:The atlas is special with no vertebral body and no spinous process, which is constituted by anterior arch, posterior arch, two lateral masses and transverse process. No structure of pedicle of vertebral arch can be found in classic anatomy, but massive anatomical observations reveal that the connecting part between the posterior arch of atlas and lateral mass resemble pedicle of vertebral arch of other spines in structure and mechanics. Anatomical and imaging measurements demonstrate that atlas lateral mass screw can be fixed through posterior arch and pedicle of vertebral arch, which is called atlas pedicle screw. Measurement data present that the data in the anatomy and image are consistent, therefore, imaging measurement can guide the placement of pedicle screw in surgery. One of the key points in successful placement of pedicle screw lies in taking control of the entry point and the angle of pedicle screw. Through axial CT measurement of atlas, the study is to confirm the safe placement area and corresponding entry angle of atlas pedicle screw, and to guide the clinical operations.Methods:With random selection of spiral CT thin-layer scanning and three-dimensional reconstruction of atlas of38patients, the space available for the screw (SAS) is defined as the distance between two paralleled lines, one of which is the tangent line of the inner edge of transverse foramen, the other of which is the tangent line of outer edge of vertebral canal. The SAS should be at least5mm with successful placement of the atlas pedicle screw, the diameter of which is3.5mm. The minimum distance between the outer edge of vertebral canal and the inner edge of transverse foramen is the width of pedicle of vertebral arch, and the intersection of the perpendicular bisector of the width and posterior arch of atlas is the lateral boundary of safe placement area. If the intersection is beyond that intersection of tangent line and the posterior arch, the latter intersection was the lateral boundary. The tangent line, in parallel with atlas midline, is of the inner edge of transverse foramen. The intersection of central axis line of screw channel and posterior arch of atlas is the inner boundary when the space available for the screw is5mm. If the intersection is in the inside of that intersection of tangent line and the posterior arch, the latter intersection is the inner boundary. The tangent line, in parallel with atlas midline, is of the outer edge of vertebral canal. Measure the distance between the posterior tubercle of atlas and the inner and the lateral boundary of the safe placement area of screw, corresponding entry angle and depth of pedicle screw, and the width of pedicle of vertebral arch. Guided by preoperative spiral CT measurement,7patients were performed pedicle screw internal fixation in atlas with the application of dredging pipeline method.Results:CT measurement:the width of pedicle of vertebral arch was (9.15±2.57) mm, which was safe to fix the3.5mm screw. The safe placement area of screw:the entry point was (18.35±2.86) mm～(25.26±1.76) mm away from posterior tubercle of atlas, the entry angle of screw ranges from leaning outwards (9.09±7.45)°to leaning inwards (18.72±17.42)°. The length of screw channel was (26.20±2.69) mm～(27.04±2.51) mm. The width of the safe placement area of screw was6.91±7.66) mm. The transverse angle was (27.81±10.32)°. But there were individual differences. The duration of operation of the7patients was90～120min, and intraoperative hemorrhage was60～300ml, with no vertebral artery injury, no nerve root injury. or no spinal cord injury. After surgery the7patients were examined by X-film and spiral CT of cervical spine, which revealed that the14pedicle screw positions were ideal within the safe placement area of screw measured before surgery, with no break-through of bone cortex of pedicle of vertebral arch. The7patients were followed up from6to12months, which showed no loosening and breakage of internal fixation and bone fusion were observed in all7patients.Conclusion:There exists safe placement area in fixing pedicle screw. The fixation of pedicle screw in the safe placement area can lean inwards or lean outwards according to the entry point of screw. It is critical for successful surgery to have exhaustive preoperative imaging measurement, to confirm safe placement area of screw, and to fix pedicle screw individually.更多还原