不同长度的下颈椎经关节螺钉侧位X线片评价

目的评价侧位X线片在了解下颈椎经关节螺钉固定中不同长度螺钉钉尖安全位置的作用。方法选用7具尸体颈椎标本,从C3、4~C5、6直视下依次置入经关节螺钉,分别置入螺钉钉尖仅为四层皮质固定(0mm)和超出皮质2、4、6mm各42枚,分别摄标本侧位X线片。根据X线片,将每个椎体分为前Ⅰ、Ⅰ、Ⅱ、Ⅲ和Ⅳ区。逐一记录螺钉钉尖在X线片上相应椎体各区的位置。结果共有87枚螺钉位于前Ⅰ区,其中42枚是当螺钉钉尖为四层皮质固定时(100%);37枚是当钉尖超出下位椎体上关节突侧前方皮质2mm时(88%);8枚是当钉尖超出4mm时(19%)。共有71枚螺钉位于Ⅰ区,其中5枚是当钉尖超出2mm时(2%);34枚是当钉尖超出4mm时(80%);32枚是当钉尖超出6mm时(76%)。10枚位于Ⅱ区的螺钉均是当钉尖超出6mm时的投影。没有发现螺钉钉尖位于Ⅲ区和Ⅳ区。不同长度的经关节螺钉钉尖在侧位X线片上的投影位置在颈椎各节段间差异无统计学意义(P>0.05)。结论在评价下颈椎经关节螺钉固定中不同长度的螺钉钉尖安全位置方面,侧位X线片有一定意义。下颈椎经关节螺钉理想长度的钉尖位置应该位于前Ⅰ区。     

下颈椎前路椎弓根螺钉固定系统的设计与运用

目的：研究下颈椎前路椎弓根螺钉钢板系统运用的可行性,为临床使用提供依据。方法：对16具颈椎标本随机分割获得C3．4,C4加C5．6,C6,7各8个运动单元（functionalspinalunit,FSu）,共32个FSU。运用下颈椎前路椎弓根螺钉钢板系统模拟植入重建FSU稳定性。测量钢板螺钉与椎体之间的适应性,运用X线摄片及CT扫描及重建评估下颈椎前路椎弓根螺钉植入的准确性,对于穿破椎弓根的标本,解剖明确其累及周围组织的情况。结果：32个FSU共计植入下颈椎前路椎弓根螺钉64枚,所有螺钉均顺利植入,无术中植入困难者。螺钉植入后与钢板螺钉孔之间的匹配程度好,未见难以锁紧的情况。钢板与椎体之间适应性良好。X线片提示所有64枚下颈椎前路椎弓根螺钉植入位置满意,螺钉长短合适。CT横断位像提示共有6枚螺钉在下颈椎椎弓根穿出,2枚内侧皮质1度穿破,4枚1度外侧缘皮质穿破累及横突孔内侧缘,未见螺钉≥2度穿破椎弓根。2枚下颈椎前路椎弓根内侧皮质1度穿破的患者,解剖发现仅有椎管内椎弓根内侧的静脉丛累及,未见硬膜囊受压,未见神经根受累。4枚1度外侧缘穿破的患者有1枚横突孔内椎静脉的累及,未见椎动脉穿破累及的情况,但其中1枚螺钉紧换椎动脉而行。结论：下颈椎前路椎弓根螺钉钢板系统适应下颈椎前路椎弓根螺钉固定重建,有临床运用价值。     

颈椎椎弓根螺钉徒手植入技术临床研究

目的：评价颈椎椎弓根螺钉徒手植入技术(无须术中影像技术引导)的安全性和可靠性。方法：作者应用Axis内固定系统(美国枢法模公司)对36例颈椎疾病患者进行颈后路经椎弓根内固定术,共植入螺钉144枚。椎弓根螺钉植入要点为：①术前仔细观察颈椎的侧位和双斜位x线片,并予以CT扫描以评估螺钉进针点、进针方向以及螺钉的长度及直径：②术中清晰地显露颈椎侧块和突间关节,用直径3．0mm高速球形磨钻去除侧块外卜象限处骨皮质,然后用2.0mm的自制手锥沿椎弓根事先确定的方向轻轻钻入,若遇阻力则需略改变方向,使其自然置入,深约2．0cm～2．5cm。确定无误后,则安置Axis钛板和置入长度合适的椎弓根螺钉;③安装完毕后,即用C掣臂作双斜位透视,无误后关闭切口。结果：从C3到C7,共植入根弓根螺钉144枚,其中10枚(6．8％)钉初次置入后感觉松动,经校正后二次置入成功,11枚(3．5％)钉道钻孔后出血较多,但及时处理后出血停止并无不良结果。术后X线斜位片及CT片显示,16枚(11．1％)螺钉穿破椎弓根,其中10枚(6．9％)螺钉穿破椎弓根外侧皮质,4枚(2,8％)钉穿破椎弓根上侧皮质,2枚(1．3％)钉穿破椎弓根卜侧皮质。随访未发现与螺钉置入穿破椎弓根皮质仃关的神经血管损伤问题。结论：本研究提示,在事先充分的埘每个患者颈椎椎弓根X线及CT解剖结构了解的情况下,徒手置入椎弓根螺钉行颈椎后路内同定是安全查行。     

下颈椎前路椎弓根螺钉固定系统与普通前路椎体螺钉固定系统的静力学比较

目的：比较下颈椎前路椎弓根螺钉（ATPS）锁定固定系统和普通前路椎体螺钉（VBS）锁定固定系统的静力学特性。方法：采集新鲜颈椎标本16具,分解为C3.,4,C4,5,C5,6,C6,7共32个运动节段（functionalspinalunit,FSU）,其中C3,4,C4,5,C5,6,C6,7各8个。将其按照不同节段随机分成A、B两组,对所获标本椎间盘切除后模拟植骨,分别植入自行设计生产的下颈椎前路椎弓根螺钉配套钢板系统和普通颈椎前路椎体螺钉钢板系统。在生物力学试验机上行钢板的垂直拔出强度试验。结果：下颈椎前路椎弓根螺钉的最大轴向拔出力为（604．68±48．76）N,椎体螺钉为（488．24±32．42）N,两者比较差异有统计学意义（t=2．147,P〈0．05）,前路椎弓根螺钉固定系统与椎体螺钉固定系统在各FSU间差异无统计学意义（A组和B组的F值分别为2．27、2．05,P〉0．05）。结论：下颈椎前路椎弓根螺钉钢板系统的拔出力明显优于普通前路椎体螺钉钢板系统,从生物力学角度上来看具有应用可行性。     

下颈椎侧块螺钉固定安全性的解剖学研究

目的　通过解剖学研究 ,确定下颈椎侧块螺钉安全的植入途径。方法　取 2 8具C3～ 7标本 ,解剖确定安全的入、出钉点后摄取C3～ 7各椎体的横断面X线片 ,测量片上C3～ 6横突孔外缘与入钉点连线和矢状轴之间的成角。结果　侧块背面中心内侧 1mm处是安全的入钉点 ,横突与关节突相交处是安全的出钉点。C3～ 6横突孔外缘与入钉点连线和矢状轴成外偏 5～ 12° ,椎体间差异无显著性 (P >0 .0 5 )。结论　颈椎侧块外上象限是螺钉植入的安全区 ,横突与关节突相交处是安全的出钉点。颈椎侧块螺钉置入时保持外倾 15°以上 ,不会损伤椎动脉。     

颈椎椎弓根螺钉徒手植入技术的临床研究

目的 评价颈椎椎弓根螺钉徒手植入技术（无须术中影像技术引导）的安全性和可靠性。方法应用Axis内固定系统（美国枢法模公司）对36例颈椎疾病患者进行颈后路经椎弓根内固定术,共植入螺钉144枚,方法如下：①术中清晰地显露颈椎侧块和突间关节,用直径3,0mm高速球形磨钻去除侧块外上象限处骨皮质,然后用2．0mm的自制手锥沿椎弓根事先确定的方向轻轻钻入,若遇阻力则需略改变方向,使其自然置入,深约2～2,5cm。确定无误后,则安置Axis钛板和置入长度合适的椎弓根螺钉。②安装完毕后,即用C型臂X线机作双斜位透视,无误后关闭切口。结果从G～G,共植入根弓根螺钉144枚,其中10枚（6．8％）钉初次置入后感觉松动,经校正后二次置入成功,11枚（3．5％）钉道钻孔后出血较多,但及时处理后出血停止并无不良结果。术后X线斜位片及CT片显示,16枚（11．1％）螺钉穿破椎弓根,其中10枚螺钉（6．9％）穿破椎弓根外侧皮质,4枚（2．8％）穿破椎弓根上侧皮质,2枚（1．3％）穿破椎弓根下侧皮质。随访未发现与螺钉置入穿破椎弓根皮质有关的神经血管损伤问题。结论本研究提示,在事先充分的对每个患者颈椎椎弓根X线及CT解剖结构了解的情况下,徒手置入椎弓根螺钉行颈椎后路内固定安全可行。     

下颈椎经关节螺钉钢板固定的生物力学研究

目的:研究下颈椎单独经关节螺钉固定与经关节螺钉钢板固定的三维稳定性之间的差异。方法:12具新鲜人体颈椎标本,制成C4,5、C5,6节段三柱损伤模型。随机选取6具标本在C4,5、C5,6行单独经关节螺钉固定,另6具标本在C4,5、C5,6行经关节螺钉钢板固定。在非限制性和非破坏性的试验条件下测试它们在前屈、后伸、左右侧弯和轴向旋转运动状态的稳定性,分别测试标本损伤模型制作前完整标本组(A组)、单独经关节螺钉固定组(B组)和螺钉钢板组(C组)3组数据。结果:单独经关节螺钉固定组和经关节螺钉钢板固定组在各方向的运动范围(ROM)和中性区(NZ)的均数均小于完整标本组,差异有统计学意义(P0.05)。经关节螺钉钢板固定在前屈运动中的ROM和NZ与单独经关节螺钉固定比较,差异无统计学意义(P0.05);在后伸、左右侧弯和轴向旋转运动中,经关节螺钉钢板固定的稳定性优于单独经关节螺钉固定,差异有统计学意义(P0.05)。结论:下颈椎经关节螺钉钢板固定的稳定性优于单独经关节螺钉固定,在使用下颈椎经关节螺钉时,相对于单独螺钉固定,建议以螺钉钢板形式固定。     

C2/3经关节螺钉固定的临床应用解剖研究

目的研究C2/3侧块关节螺钉固定的解剖可行性,为颈椎后路钉板固定在枢椎提供新的螺钉锚点.方法利用20例配套颈椎干骨标本,测量枢椎和第三颈椎侧块的宽度和高度.设定C2/3侧块关节螺钉的进钉点和进钉方向,即进钉点在头尾方向上位于枢椎侧块的中下1/3交界处,在内外方向上位于枢椎侧块的中央,螺钉穿枢椎侧块经由C2/3侧块关节进入C3侧块;进钉方向与人体矢状面平行,并与C2/3侧块关节面呈90°角,测量螺钉分别在枢椎和第三颈椎侧块内的长度.结果枢椎侧块的平均宽度和高度分别是14.83mm和9.63mm;第三颈椎侧块的平均宽度和高度分别是13.86mm和11.27mm.螺钉在枢椎和第三颈椎侧块内的平均长度分别是6.24mm和9.70mm,螺钉总长平均15.94mm.结论经C2/3侧块关节进行螺钉固定在解剖学上是可行的,可以作为枢椎后路螺钉固定的补充方法.     

下颈椎关节突关节的解剖学测量与经关节螺钉固定的关系

目的:测量下颈椎关节突关节的相关数据,探讨其与经关节螺钉固定的关系。方法:41具成人颈椎干燥标本,测量其颈椎关节突关节的上、下关节面的高度、宽度和冠状面角度以及下关节面在侧块后方投影的高度,并对侧块进行形态学评定;根据Dalcanto技术对30具颈椎标本行经关节突关节螺钉固定,以侧块中心点下2mm为进钉点,在矢状面上尾倾40°、在冠状面上外倾20°置入螺钉,测量螺钉的长度,观察螺钉位置。结果:C3～C7下关节面在侧块后方投影的高度为7.4～9.0mm,侧块的中心点约在下关节面后方投影的上界下方2mm。C6和C7上、下关节面的倾斜角度相对更大,侧块厚度相对较薄。采用Dalcanto技术经关节突关节螺钉固定,螺钉长度从C3/4向C7/T1呈下降趋势,由16.9mm降至15.7mm,其中在C7/T1水平螺钉最短。螺钉由头侧向尾侧经关节突关节复合体,大体上从关节面的中心点穿过;在矢状面上几乎与关节面垂直;无一例损伤到横突孔,螺钉从下位椎体的上关节突基底部的侧前方穿出,钉道指向侧前下方。结论:下颈椎关节突关节复合体可为经此关节螺钉固定提供足够的皮质骨。Dalcanto技术经关节突关节螺钉不仅具有可行性,而且可以避开横突孔,钉道方向几乎与横突沟平行,安全空间较大。由于C6、C7侧块的厚度较薄,在C6/7和C7/T1行经关节固定时不宜使用16mm以上长度的螺钉。     

颈椎斜位片在下颈椎椎弓根螺钉术的研究

目的通过C形臂X线机以不同角度拍摄的尸体颈椎样本的斜位片观测颈椎椎弓根。在此基础之上不同角度的颈椎斜位片上观察术前拟行下颈椎椎弓根钉植入的患者颈椎椎弓根影象学表现。在这两个观测的基础上找到颈椎椎弓根及螺钉植入的最佳斜位片角度。方法选用干燥的人颈椎(C3~7)标本在C形臂X线机辅助下通过透视不同的斜位角度(40°、45°、50°、55°、60°)观测椎弓根。同时在颈椎标本观测的基础上,对拟行颈椎椎弓根螺钉植入患者术前摄不同角度的颈椎斜位片(45°、50°、55°)观测颈椎椎弓根的显示。两次试验都是观测椎弓根的长度及对侧椎弓根在椎体上显影的位置(把椎体3等分)。结果通过测量发现55°颈椎双斜位片对椎弓根长度的显示及对侧椎弓根位置显示与其他角度斜位片相比有明显的统计学差异(P<0.05)。结论55°双斜位片对术前颈椎椎弓根的判断及术中椎弓根钉植入准确性的判断是斜位片的最佳角度。     

Lateral radiological evaluation of transarticular screw placement in the lower cervical spine

This study assessed the ideal district of lateral radiograph in evaluation of transarticular screw placement in the lower cervical spine. To assess the ideal zone of lateral radiographs in determining the safe or hazardous locations of the screw tips during transarticular screw implantation in the lower cervical spine. Transarticular screw in the lower cervical spine had been used as an alternative technique to achieve posterior cervical spine stability. Injury to the spinal nerves caused by transarticular screws which are too long must be identified quickly to minimize the neurologic complication. No previous radiological study regarding evaluation of the transarticular screw placement using lateral radiographs has been reported. Twelve cervical spines were removed from embalmed cadavers. Four transarticular screw placements with Dalcanto’s technique under direct visualization, including placement of the screw tip staying the ventral cortex, 2, 4 and 6 mm over-penetration of the ventral cortex, were performed on each specimen. Following each placement, a lateral radiograph was taken. Each vertebral body was divided vertically into four equal zones, and another equal zone posterior to the posterior border of the vertebral body was defined as Zone pre-1. The numbers of screw tips seen in each zone were quantified for each placement. Partitions of χ ² method was used to evaluate the ideal zone on lateral radiograph for transarticular screw insertion. At C34 and C45, no significant difference was found between Zone pre-1 and Zone 1 (χ ² = 0.18, P > 0.50), while there was significant difference between Zones 1 and 2 (χ ² = 73.6, P < 0.005), as well as Zones 2 and 3 (χ ² = 13.2, P < 0.005). At C56 and C67, No significant difference was found between Zones 2 and 3 (χ ² = 0.25, P > 0.50), while there was significant difference between Zone pre-1 and Zone 1 (χ ² = 66.2, P < 0.005), as well as Zones 1 and 2 (χ ² = 10.5, P < 0.005). Ideal screw tip positions on lateral radiograph for transarticular screw by Dalcanto’s technique should be in Zone 1 at C34 and C45, in Zone pre-1 at C56 and C67. If the screw tip was in Zones 3 and 4, the safe rate will be decreased significantly and it might be too deep and be dangerous.     

Computed tomography in the determination of transarticular C1-C2 screw length

This study evaluated the significance of computed tomographic (CT) measurements of the upper cervical vertebrae and their clinical implications in transarticular C1-C2 screw placement. In the first part of the study, analysis of axial CT scans of the atlas of 46 patients who had a normal C1-C2 region was performed. Measurements included the vertical distance between the middle of the ventral cortex of the lateral mass and the anterior-most point of the anterior tubercle, and the angle of the anterior ring of C1 relative to the frontal plane. In the second part, axial CT scans of the upper cervical spine were performed in seven cadaveric cervical spines and analyzed using the same criteria. Using the Magerl technique of transarticular C1-C2 screw placement, one screw was placed in each cervical spine. Following each placement, a strict lateral radiograph was taken and the distance between the tip of the screw and the anterior-most point of the anterior tubercle of C1 was measured. Analysis of the cervical cadaveric specimens showed the vertical distance between the middle of the ventral cortex and the anterior-most part of the anterior tubercle when measured on CT scan corresponded to the distance measured on lateral radiographs after placement of the C1-C2 transarticular screw. The study of the 46 patients with normal C1-C2 region had shown the mean values of linear and angular measurements to be greater in males than in females, although no significant difference was found between the two groups (P>.05). The mean distance between the anterior-most point of the anterior tubercle and the middle of the ventral cortex of the lateral mass was 6.5+/-1 mm, and the mean transverse angle of the anterior ring relative to the frontal plane was 22 degrees+/-3.1 degrees. Axial CT evaluation of the individual anatomic relationships of the atlas is simple and may be a useful guide in the determination of the length of the transarticular screw when performed during surgery under lateral fluoroscopic control.     

下颈椎经关节螺钉联合侧块或椎弓根螺钉固定的效果

目的 探讨在下颈椎经颈后正中入路应用经关节螺钉联合侧块螺钉或椎弓根螺钉行内固定治疗的固定效果.方法 2003年2月至2007年10月,对22例患者通过后路应用经关节螺钉联合侧块螺钉或椎弓根螺钉行内固定治疗,男14例,女8例;年龄24～73岁,平均43岁.其中下颈椎创伤性骨折脱位13例,颈椎后纵韧带骨化症4例,颈椎管狭窄伴Ⅱ型齿突骨折1例,颈椎间盘突出伴椎管狭窄4例.结果 共置入经关节螺钉45枚,其中C4,5 2枚,C5,639枚,C6,74枚;共置入侧块螺钉12枚,C3、C4各6枚;共置入椎弓根螺钉41枚,其中C24枚,C32枚,C46枚,C721枚,T18枚.术中所有螺钉均成功置入,未出现椎动脉、神经根和脊髓损伤等置钉相关并发症.22例患者均获随访,随访时间10个月～3年8个月,平均17个月.植骨融合时间3～5个月,平均3.5个月.术后发现1例患者的2枚经关节螺钉松动,部分脱出.经加强颈托制动,术后4个月获得融合.结论 通过后路固定下颈椎时,采用经关节螺钉联合侧块螺钉或椎弓根螺钉固定,均可取得较好的固定效果.     

下颈椎侧块螺钉固定与椎动脉、神经根的解剖关系及评价

目的　通过解剖学研究和影像学手段 ,了解下颈椎侧块螺钉固定与椎动脉之间的关系以及斜位片在置钉过程中对神经根的监测价值。方法　 (1)取 2 8具尸体的C3 ～C7标本 ,年龄 2 8～ 79岁。摄取标本各椎体的横断面片 ,测量X线片上C3 ～C7横突孔外缘与侧块背面中心内侧 1mm处的连线在横断面上与矢状轴之间的成角。 (2 )取 10具标本 ,以侧块背面中心点内侧 1mm处为入针点、横突与侧块相交处为出针点在C3 ～C6侧块内置入克氏针。当针尖未超出或超出侧块远侧皮质 2、4、6mm时 ,摄取标本左右 4 5°斜位片。把斜位片上椎间孔分为上、下两部分 ,上部实际是真正的椎间孔 ,下部则相当于横突间孔位置。观察针尖在斜位片上椎间孔内的位置并计数 ,同时与实际解剖比较两者的一致性。　结果　 (1)C3 ～C6横突孔外缘与侧块背面中心内侧 1mm处的连线在横断面上与矢状轴成外偏 5°～ 12°的角度 ,椎体间差别无统计学意义 (P >0 0 5 )。 (2 )以横突与关节突相交处为出针点 ,实际观察当针尖超出侧块远侧皮质 2mm时 ,未突入横突间孔 ;当超出距离为 4、6mm时 ,针尖则突入横突间孔。X片上显示当针尖未超出远侧皮质时 ,斜位片上有 15 %针尖出现于椎间孔下部 ;当针尖超出 2mm时 ,斜位片 4 1 3%针尖出现于椎间孔下部 ;当针尖超出 4mm     

Cervical transfacet versus lateral mass screws: a biomechanical comparison

The authors directly the compared biomechanical pullout strength of screws placed in the cervical lateral masses to that of screws placed across the facet joints. Posterior cervical fixation with lateral mass plates is an accepted adjunctive technique for cervical spine fusions. Altered anatomy resulting from congenital malformation, tumor, trauma, infection, or failed lateral mass fixation may limit traditional screw placement options. Transfacet screw placement, which has been studied extensively in the lumbar spine, may offer an alternative when posterior cervical fusion is required. Ten fresh human cadaveric cervical spines (postmortem age range, 69 to 91 years) were harvested. On one side, transfacet screws were placed at the C3-4, C5-6, and C7-T1 levels. On the other side, lateral mass screws were placed at the C3, C5, and C7 levels. The screw insertion technique at each level was randomized for right or left. After screw placement, each set of vertebral bodies were dissected and mounted in a custom jig for axial pullout testing using a servohydraulic testing machine. The load-displacement curves were obtained for each screw pullout. The mean pullout strength for the screws placed across the facets was 467 N (range, 192 to 1,176 N). This compares with 360 N (range, 194 to 750 N) for the lateral mass screws (p = 0.008). At each level, transfacet screws exhibited greater pullout resistance compared with the lateral mass placement, but the difference was most pronounced at the C7-T1 level (lateral mass = 373 N, transfacet = 539 N, p = 0.042). Cervical transfacet screw placement provides pullout resistance that is comparable to, if not greater than, lateral mass placement. This type of placement, although technically difficult, may be an alternative to lateral mass screws in cases with unusual anatomy, stripped screws, or when additional intermediate points of fixation are desired.     

颈椎经关节椎弓根螺钉固定与标准椎弓根螺钉固定的生物力学比较

目的 比较颈椎经关节椎弓根螺钉固定和标准椎弓根螺钉固定的拔出强度.方法 取10具新鲜尸体颈椎标本(C_3～T_1),游离成三个颈椎运动节段(C_(3,4),C_(5,6),C_7T_1).在椎体两侧随机进行经关节椎弓根螺钉固定或标准椎弓根螺钉固定,置入直径3.5 mm皮质骨螺钉.经关节椎弓根螺钉固定以上位椎骨侧块外下象限中点为进钉点,在直视椎弓根下,螺钉在冠状面内倾约45°、矢状面尾倾约50°.由上位椎骨下关节突经关节突关节、下位椎骨的椎弓根,进入下位椎骨的椎体内.标准椎弓根螺钉固定以侧块外上象限中点为进钉点,在直视椎弓根下,螺钉方向参考CT测量结果 ,尽量与椎弓根倾斜角度保持一致,在横断面上内倾约45°、矢状面上螺钉指向椎体的上1/3.在生物力学试验机上行拔出强度试验,比较两种螺钉固定的最大轴向拔出力.结果 颈椎经关节椎弓根螺钉固定平均最大轴向拨出力为(694±42)N,标准椎弓根螺钉固定为(670±36)N,两者比较差异有统计学意义(P<0.05).结论 颈椎后路经关节椎弓根螺钉固定的拔出强度大干标准椎弓根螺钉固定,从生物力学强度方面考虑经关节椎弓根螺钉固定可以作为标准椎弓根螺钉固定的一种补充方法.     

下颈椎关节突关节与椎体后缘关系的影像学研究

目的：研究探讨下颈椎关节突关节前缘与椎体后缘的位置关系，为临床行下颈椎经关节螺钉植入时评价进钉深度提供参考。方法：选取无明显下颈椎畸形的标准颈椎侧位X线片100张，下颈椎标准CT平扫片50张，测量下颈椎关节突关节顶点、中部、基底部前缘与椎体后缘的距离（分别记为HS，HM，HI），椎体后缘之前为负、之后为正。并对测量数据行统计学分析。结果：所有关节突关节前缘距离、椎体后缘的距离从顶点到基底部逐渐减小（HS〉HM〉HI）。C。关节突关节前缘大多位于椎体后缘之前（HS，HM，HI均为负值）；C4.5C5.6关节突关节前缘逐渐后移；Co，，关节突关节前缘均位于椎体后缘之后（HS，HM，HI均为正值）。下颈椎关节突关节顶点前缘与椎体后缘的距离HS从C。到C6，7逐渐增大，C3．4为（0±0．25）mm，C4．5为（2．03±0．47）mm，C5．6为（2．45±0．56）mm，C6．7为（2．91±1．05）mm；下颈椎关节突关节中部前缘与椎体后缘的距离HM从C3.4到C6.7逐渐增大，C3.4为（-1．57±0.53）mm,C4.5为（O．50±0．26）mm，C5．6为（0．56±0．36）mm，C6．7为（1．54±0．39）mm；下颈椎关节突关节基底部前缘与椎体后缘的距离HI从C3.4到C6.7逐渐增大，C3.4为（-2．03±0．40）mm，C4．5为（0±0．30）mm，C5，6为（0．50±0．44）mm，C6．7为（1．08±0．70）mm。结论：在行下颈椎经关节螺钉固定时，螺钉的头部在C3.4应位于相应榷体后缘前方0～2mm，C4.5应位于相应椎体后缘之后0-2mm，C5.6应位于相应椎体后缘之后0．5-2．5him，C6.7应位于相应椎体后缘之后1～3mm。下颈椎关节突关节前缘与椎体后缘关系的确立，可为临床工作中下颈椎经关节螺钉植入时判断进钉深度提供参考。     

Lateral mass screw fixation for cervical spine trauma: associated complications and efficacy in maintaining alignment.

BACKGROUND CONTEXT: Many studies have documented the efficacy of lateral mass screws, but there are no studies examining the alignment maintenance capability and few large studies examining the complications associated with the use of these devices in cervical spine trauma. PURPOSE: To evaluate complications and alignment maintenance capability associated with lateral mass screw placement for cervical spine trauma by one surgeon at one institution. STUDY DESIGN: A retrospective chart and radiograph review of adult patients who underwent lateral mass screw fixation after traumatic injuries to the cervical spine. PATIENT SAMPLE: Of 34 consecutive patients with cervical spine injuries who were treated surgically at a level-I regional trauma center, 29 met the inclusion criteria and formed the study group. OUTCOME MEASURES: Sagittal alignment, screw placement, and fusion were assessed on postoperative radiographs. METHODS: Inclusion criteria included an unstable cervical vertebral fracture or a fracture-dislocation treated with posterior spine fusion and lateral mass instrumentation and a minimum follow-up of 24 months. A review of hospital charts, operative reports, clinic notes, and plain radiographs for the 29 patients was performed, with an emphasis on operative and postoperative complications and alignment maintenance. RESULTS: For 28 of the 29 patients, the mean change in sagittal alignment from the immediate postoperative to the most recent follow-up radiographic examination was 2 degrees (range, 0 degrees to 6 degrees ). Radiographically, there was one case of instrumentation/fixation failure and loss of sagittal alignment 3 months postoperatively. Other complications included one case of C5 nerve root injury and four wound infections. CONCLUSIONS: The use of lateral mass screws for traumatic injuries of the cervical spine is associated with excellent maintenance of alignment and minimal complications.