儿童枢椎椎弓根及椎板螺钉内固定的解剖学研究

目的：探讨儿童枢椎椎弓根及椎板螺钉内固定的可行性。方法收集2009年至2012年广州军区广州总医院儿童颈椎薄层CT影像资料32套,其中年龄2～5岁（幼龄组）及5～10岁（学龄组）各16套32侧。测量枢椎椎弓根虚拟钉道宽度、长度、内倾角,椎板虚拟钉道峡部宽度、长度及外展角数据。结果幼龄组椎弓根虚拟钉道宽度＞3.5 mm为15侧、学龄组为26侧;幼龄组椎板虚拟钉道峡部宽度＞3.5 mm为24侧、学龄组为31侧。两组比较,差异均有统计学意义（P＜0.05）。幼龄组和学龄组椎弓根虚拟钉道平均宽度、平均长度,椎板虚拟钉道峡部平均宽度、平均长度比较,差异均有统计学意义（P＜0.05）;两组椎弓根虚拟钉道内倾角、椎板虚拟钉道外展角比较,差异无统计学意义（P＞0.05）。结论对于5～10岁的学龄期儿童,可根据情况选用枢椎椎弓根螺钉或椎板螺钉内固定方式;而对于年龄＜5岁的低龄患儿,术前需基于患儿颈椎薄层CT扫描螺钉内固定相关解剖参数的精确测量和评估,合理选择枢椎椎弓根螺钉、椎板螺钉或混搭式固定,以保证手术的安全性和内固定的可靠性。     

国人成年男性胸腰椎椎弓根径线和偏角与脊椎节段序数的相关性研究

目的:探讨胸腰椎椎弓根的径线和偏角与脊椎节段序数的相关性.方法:46具国人成年男性脊柱标本,拍胸椎及腰椎侧位X线片,并进行CT扫描.测量每个椎体椎弓根钉道长度、椎弓根内径宽度、椎弓根间距、椎弓根与矢状面夹角(e角)和椎弓根与横断面夹角(f角).将T1～L5脊椎节段序数按照1～17进行编号.应用SPSS 11.5软件进行统计分析.结果:T1-L4椎弓根钉道长度与脊椎节段序数呈正的直线相关(R2＝0.716);T2～T3椎弓根宽度与脊椎节段序数呈负的直线相关(R2=0.792);T8～L5椎弓根宽度与脊椎节段序数呈正直线相关(R2=0.673).T1～T4椎弓根间距与脊椎节段序数呈负直线相关(R2=0.866);T4-L5椎弓根间距与脊椎节段序数呈正的直线相关(R2＝0.771).T1～T2椎弓根f角与脊椎节段序数呈正直线相关(R2=0.767);T2～T4椎弓根f角与脊椎节段序数呈正直线相关(R2=0.908);T7～L5椎弓根f角与脊椎节段序数呈负的直线相关(R2=0.931);T1～T6椎弓根e角与脊椎节段序数呈负的直线相关(R2=0.774),T12～L5椎弓根e角与脊椎节段序数呈正的直线相关(R2=0.710).而T1～T2及T4～T7椎弓根宽度、T4～T6椎弓根f角以及T6-T12椎弓根e角与脊椎节段序数之间无显著相关性.结论:除T1～T2和T4～T7椎弓根宽度、T4～T6椎弓根f角以及T6～T12椎弓根e角外,国人成年男性胸腰椎椎弓根径线和偏角与脊椎节段序数之间有线性相关性,其回归方程有显著性意义.     

改良CT测量法用于椎弓根螺钉个体化植入的实验研究

[目的]探讨进钉点到棘突中心矢状面的垂直距离用于椎弓根螺钉个体化植入的可行性.[方法]于华中科技大学同济医学院解剖教研室收集成人脊柱标本30例,在CT横断面扫描图像上测量如下数据:椎弓根宽度a,进钉点到椎体前缘的距离b,进钉点到棘突中心矢状面的垂直距离c,椎弓根纵轴与椎体矢状轴的夹角A,在侧位片上测量椎弓根纵轴与操作台垂直线的夹角B,分为实验组和对照组,实验组采用CT图像上进钉点到棘突中心矢状面的垂直距离用于进钉点在水平方向上的定位,对照组采用Ebraheim法定位进钉点,置钉后行CT扫描,判断螺钉有无穿破椎弓根内侧或外侧壁及穿破程度,按照穿破程度进行分级:A=完全位于椎弓根内;B:穿破程度＜2 mm;C=穿破程度2～4 mm;D=穿破程度＞4 mm,并进行对比分析.[结果]实验组T3-10水平螺钉穿破率明显低于对照组,T1,T2,T 11,12:两组的穿破率相当.在T 3-18水平,螺钉的穿破程度(C,D级)明显高于其他节段,与椎弓根在这些节段横径变小有关;T 1-12,实验组中C,D级的发生率低于对照组.[结论]采用进钉点到棘突中心矢状面的垂直距离用于定位椎弓根螺钉进钉点,可以明显提高螺钉在水平方向上的植入准确性.尤其在L 3-10节段,而且特别适合由于解剖变异,外伤,肿瘤破坏等原因使关节突关节,横突等解剖标志发生改变时椎弓根螺钉的植入,亦可以在正常解剖情况下作为传统定位方法的有效补充.     

枢椎椎弓根骨折半螺纹螺钉固定长度的影像学研究

 目的影像学测量枢椎椎弓根不同部位骨折后路半螺纹螺钉的固定长度。方法收集2007年6月至2013年6月收治非Hangman骨折致寰枢椎损伤汉族患者的影像学资料,枢椎椎体及关节突间部（椎弓根）骨折者均以排除,共160例患者资料纳入研究,男120例,女40例;年龄18~72岁,平均41.4岁。在ADW 4.4工作站行CT三维重建,选取枢椎椎弓根钉道设计图像,以Ebraheim法确定枢椎进钉点,测量自进钉点经枢椎椎弓根最狭窄部位中点至枢椎体前方皮质骨后缘的距离（半螺纹螺钉长度）;模拟临床常见的三种枢椎椎弓根骨折（经椎体后壁骨折、经峡部骨折、经椎板前缘骨折）的骨折线,分别测量自进钉点至骨折线的距离（螺杆长度)和自骨折线至枢椎椎体前方皮质骨后缘的距离（螺纹长度）。观察身高、性别、不同部位骨折半螺纹螺钉长度、螺杆长度及螺纹长度的规律。结果男性身高162~177 cm,平均（167±7.9） cm;女性身高151~167 cm,平均（156±6.6） cm。枢椎椎弓根骨折后所需半螺纹螺钉长度男性平均（28.8±3.2）mm;女性（24.7±2.6） mm,男性半螺纹螺钉较女性长（t=6.50,P< 0.05）。患者身高与半螺纹螺钉长度呈正相关（r=0.667,P<0.01）。骨折线越靠近枢椎体后壁半螺纹螺钉的螺杆越长、螺纹越短,经椎体后壁骨折组螺杆长度男性平均17 mm、女性15 mm,螺纹长度男性平均12 mm、女性10 mm;经峡部骨折组螺杆长度男性平均14 mm、女性13 mm,螺纹长度男性平均15 mm、女性12 mm;经椎板前缘骨折组螺杆长度男性平均10 mm、女性9 mm,螺纹长度男性平均18 mm、女性15 mm。结论枢椎椎弓根骨折后路手术中使用的半螺纹螺钉长度与身高、性别有关。椎弓根骨折部位不同,所需半螺纹螺钉的螺杆、螺纹长度也不相同。     

漏斗技术结合徒手椎弓根探针技术在椎弓根置钉术中的应用

目的探讨利用漏斗技术结合徒手椎弓根探针技术置入椎弓根钉的安全性及准确性。方法术前测量目标椎的e角、f角及椎弓根直径,选择准确的进针点:骶椎以下关节突左7点右5点为进针点,腰椎以人字嵴顶点作为进针点,胸椎按Kim推荐的入点进针。在椎弓根入口去皮质后据e、f角徒手推进椎弓根探针至椎体前缘,测量所需螺钉长度,再沿钉道扩孔、攻丝及置入相应直径与长度的螺钉;术后CT片按照椎弓根内侧壁穿透<2 mm,外侧壁穿透<4 mm作为安全评价标准。回顾性分析自2009年6月~2012年1月利用该技术在184例中置入736枚椎弓根钉的情况。结果所有螺钉椎弓根内侧壁穿透<2 mm,外侧壁穿透<4 mm,总合格率100%;无一例出现神经根或脊髓损伤加重的表现,无一例出现脑脊液漏。结论利用合理的进针点,在个体化置钉的基础上,利用漏斗技术结合徒手椎弓根探针技术能成功置入胸腰椎椎弓根钉。     

螺钉植入后椎弓根横径膨胀的初步观察

目的观察椎弓根植钉前后横径是否存在膨胀现象及其影响因素。方法采用新鲜尸体骨标本T2～L1共4具,均为女性,年龄25～50岁,平均41岁。将标本分解为单个椎体48个,共96个椎弓根。植钉前使用游标卡尺测量椎弓根横径,使用双能X线骨密度仪检测骨密度,随后对椎弓根进行骨密度(A)和直径比(椎弓根螺钉直径/椎弓根横径×100%,B)的3×3析因分组,共分为9组(A1B1,A1B2,A1B3,A2B1,A2B2,A2B3,A3B1,A3B2,A3B3)。按分组情况,使用同一类型螺钉,遵循统一标准植入螺钉,植钉后立即测量椎弓根横径。结果11例数据失效,包括6例椎弓根崩裂,其中A3B3组4例。有效实验数据为85个,经统计学分析:椎弓根植钉前后横径存在膨胀现象,且椎体骨密度和螺钉直径/椎弓根横径比均对椎弓根的膨胀率有显著影响(P<0.05),但两者之间无交互作用(P>0.05)。结论在行椎弓根系统内固定手术时,应考虑植钉后椎弓根的膨胀现象,以及椎弓根膨胀率与椎体骨密度、螺钉/椎弓根直径比之间的关系。椎弓根膨胀可能直接或间接引发相关临床症状。     

成人胸椎安全置入椎弓根钉相关的解剖形态特点及意义

目的分析安全置入胸椎椎弓根钉相关的椎弓根解剖形态特点,研究在探设成人胸椎椎弓根钉通道过程中需要重点探查的区域。方法使用CT三维重建图像对60位正常发育的成人胸椎椎体和15例胸椎椎弓根钉穿出椎弓根内侧壁的胸椎手术患者进行测量。测量参数包括:临界距离,安全距离,椎弓根钉通道长度,椎弓根宽度,椎弓根横向角,穿出距离。危险区域定义为安全距离和临界距离之差。结果成人不同节段胸椎的临界距离为8.69~10.53 mm,安全距离为14.53~16.16 mm,危险区域为5.10~6.41 mm。临界距离、安全距离与危险区域相对恒定。椎弓根钉通道长度为31.21~45.01 mm,椎弓根宽度为4.03~8.29 mm。椎弓根横向角从T1的27.68°逐渐减少到T12的7.82°。15枚穿出椎板腹侧皮质或者椎弓根内侧皮质的椎弓根钉的穿出距离为(12.68±1.12)mm,所有的穿出距离均介于临界距离和安全距离之间。结论正确认识成人胸椎的临界距离、安全距离和危险区域有助于安全置入胸椎椎弓根钉。     

小牛与人颈椎解剖结构的比较

目的比较小牛与人颈椎节段的解剖结构,探讨小牛颈椎是否合适在脊柱体外研究中替代人的脊柱标本。方法对12具小牛颈椎标本和8具人体颈椎标本进行形态解剖学测量。测量C1-7的椎体宽度、椎体长度、椎体高度、椎管的宽度、椎管的深度、椎弓根宽度、椎弓根高度、椎弓根角度、椎体总宽度及椎体总深度。结果小牛颈椎从C3-7与人颈椎在解剖学上比较相似,但也有许多不同：①小牛颈椎比人大,人颈椎大约为小牛颈椎的75％;②小牛颈椎椎弓根比人粗,椎弓根角比人大;③小牛颈椎横突比人短;④小牛颈椎棘突短且多为水平位;⑤小牛颈椎齿突长宽明显比人大。结论本研究为小牛颈椎动物实验研究提供了解剖学参考数据;小牛颈椎解剖在某些方面与人具有相似性,还需进一步研究其与人颈椎间生物力学的差异。     

胸椎椎弓根形态测量研究

目的:观察不同节段胸椎椎弓根形态特征,探讨其临床意义。方法:测量40具国人胸椎标本的椎弓根横径、矢状径、矢状面夹角、椎弓根间距、椎弓根后缘皮质到椎体前缘皮质距离及椎弓根-椎板夹角,观察椎弓根后缘中点与相应横突根部的关系。结果:（1）除T1外,各节段椎弓根矢状径均明显大于横径（P<0.01）;（2）椎弓根矢状面夹角从T1到T9逐渐减小,T10以下为负角;（3）椎弓根后缘皮质沿其轴线到椎体前缘的长度从T1到T7逐渐增加,T7到T12基本相同;（4）T1与T12椎弓根螺钉拟进钉点位于横突根部中点,T2及T11位于横突根部中上1/3点,其余各节段均位于横突根部上缘。结论:进行胸椎椎弓根螺钉固定时,应根据不同节段椎弓根形态特点,结合X线片或CT片,选择相应的螺钉直径、长度、进钉部位及方向。     

枢椎棘突螺钉与椎弓根螺钉固定的生物力学拔出力比较

目的 比较枢椎棘突螺钉和椎弓根螺钉的生物力学拔出力强度.方法 取8具新鲜尸体枢椎标本(C2).于椎体两侧随机进行枢椎棘突螺钉和椎弓根螺钉固定,置入直径为4.0 mm的皮质骨螺钉.枢椎棘突螺钉进钉点选择为棘突的基底部、棘突及椎板的交界处,进钉角度为水平置钉,螺钉由对侧棘突基底部穿出,形成双层皮质固定;枢椎椎弓根螺钉在直视椎弓根下置钉.置钉后行拔出强度实验,比较2种螺钉的最大轴向拔出力强度.结果 枢椎棘突螺钉的平均拔出力强度为(387.56±137.73)N,稍小于枢椎椎弓根螺钉的平均拔出强度(465.25±214.32)N,差异无统计学意义(t=-0.862,P =0.403);枢椎棘突螺钉的平均钉道长度为(21.42±1.14) mm,稍短于枢椎椎弓根螺钉的(23.16±1.01) mm,差异有统计学意义(t=4.368,P ＜0.05). 结论 枢椎棘突螺钉具有椎弓根螺钉相近的生物力学拔出力强度,枢椎棘突螺钉在生物力学上具有应用可行性.     

幼猪胸腰椎椎弓根参数的CT测量对置钉的指导意义

[目的]采用CT扫描测量约克夏幼猪的胸腰椎椎弓根螺钉置入的相关参数,提供动物实验的解剖学参考数据。[方法]10只6周龄的雌性约克夏幼猪进行CT平扫三维重建后测量T1～L5的椎体高度、椎体横径、椎体纵径、椎管横径、椎弓根骨性通道全长、椎弓根宽度等参数,按照测量数据置入椎弓根螺钉,术后再次行CT扫描检查,评估螺钉置入准确性。[结果]根据CT影像学测量结果,椎弓根宽度平均为5.3～7.4 mm,椎弓根骨性通道全长平均为18.8～22.6 mm,椎弓根水平面置入角度平均为32.1°～44.4°之间。根据测量数据,选取直径为4.5 mm,长度为25 mm的椎弓根螺钉,并在幼猪脊柱成功置入,固定效果可靠。[结论]尽管幼猪的脊椎较小,通过术前CT测量的指导,可以有效地指导椎弓根螺钉的置入。     

下颈椎前路椎弓根螺钉内固定解剖学测量及临床应用

 目的 通过解剖学测量和临床应用, 探讨下颈椎前路椎弓根螺钉置入的可行性、安全性 及其临床疗效。方法 对 20具成人颈椎标本通过 CT扫描后进行数据测量, 内容包括: 椎体高度、椎体 前后径、椎体宽度、椎弓根横径、椎弓根高度、螺钉长度、横切面角度、矢状面角度、横切面进针点距离、 矢状面进针点距离, 确定进针点, 并进行尸体标本置钉。根据测量数据和术前影像学检查对 5例颈椎骨 折脱位患者行下颈椎前路椎弓根螺钉固定植骨融合术, 术后观察复位及螺钉位置情况及短期随访结 果。结果 横切面角度从 Cxiaobiaokaishi3xiaobiaojieshu(45.7°±4.0°)至 Cxiaobiaokaishi5xiaobiaojieshu(52.1°±5.9°)逐渐增大, 至 Cxiaobiaokaishi6xiaobiaojieshu(47.8°±6.7°)、Cxiaobiaokaishi7xiaobiaojieshu(44.4°±8.3°)又 有所减小。矢状面角度从 Cxiaobiaokaishi3xiaobiaojieshu(93.4°±7.2°)至 Cxiaobiaokaishi6xiaobiaojieshu(112.1°±6.2°)逐渐增大, 至 Cxiaobiaokaishi7xiaobiaojieshu(102.7°±8.5°)又有所减小。横 切面进针点 Cxiaobiaokaishi3xiaobiaojieshu~Cxiaobiaokaishi5xiaobiaojieshu位于椎弓根对侧, Cxiaobiaokaishi6xiaobiaojieshu~Cxiaobiaokaishi7xiaobiaojieshu位于椎弓根同侧;矢状面进针点距离 3.4~7.5 mm。 5例患者术 中减压彻底, 螺钉均位于椎弓根钉道内, 日本骨科协会评分(Japanese Orthopaedic Association Scores, JOA)均有不同程度地提高。结论 下颈椎前路椎弓根螺钉的理想进针点位于距上终板 5 mm左右, 椎 体前正中线附近。横切面角度约为 45.7°~52.1°, 矢状面角度约为 93.4°~112.1°。螺钉长度约为 32 mm。     

腰骶移行椎S_1椎弓根解剖测量及临床应用

目的探讨腰骶移行椎S1椎弓根进钉方法及临床初步应用效果。方法测量17例腰骶移行椎标本及30例正常骶骨标本的S1椎椎弓根横径、上下径、椎弓根中心轴线长度及角度,采用特定进钉点治疗15例腰骶移行椎患者。结果根据测量结果确定椎弓根螺钉置钉点。S1椎弓根横径:腰骶移行椎(22.47±4.67)mm,正常椎(26.72±3.76)mm(P0.05)。上下径:腰骶移行椎(20.71±2.97)mm,正常椎(25.38±4.62)mm(P0.05)。椎弓根中心轴线长度:腰骶移行椎(41.27±5.65)mm,正常椎(49.83±6.72)mm(P0.05)。移行椎椎弓根A角:腰骶移行椎6.54°±1.98°,正常椎6.31°±1.72°(P0.05);B角:腰骶移行椎43.55°±11.21°,正常椎35.71°±10.63°(P0.05)。腰骶移行椎的上关节突形态与正常者相近,但双侧不对称者多见。腰骶移行椎17例中11例出现不对称,正常椎30例中2例不对称,两者比较差异有统计学意义(P0.05)。V形槽形态在正常骶骨中不易见到,在腰骶移行椎中出现率为100%。结论腰骶移行椎后部横突变异,上关节突不对称率高,而V形槽出现恒定。以V形槽外缘3 mm处为纵线,以上关节突关节面下缘水平线为横线,其交点作为椎弓根螺钉进钉点。角度选择A角在6°左右、B角在43°左右,长度选择35~40 mm之间,临床应用收到理想疗效。     

Anatomic study of the axis for surgical planning of transarticular screw fixation

Transarticular screw fixation has shown increased stability compared with other posterior stabilization techniques. However, there have been few reports on vertebral artery injury related to the screw insertion. The current study measured the parameters of the pedicle and vertebral artery groove of the axis and clarified the accuracy and safety of the transarticular screw fixation. Direct measurements were taken from 98 dry axis vertebrae. The width and height of the pedicle were measured. The mediolateral and anteroposterior dimensions of the vertebral artery groove also were measured. Forty-one percent had asymmetry. In 20% of the specimens, the pedicle was smaller than the diameter of the screw (3.5 mm). The pedicle of the axis has large anatomic variability and asymmetry. Some pedicles were not suitable for atlantoaxial transarticular screw fixation. The risks associated with screw fixation should be prevented by preoperative computed tomography with three-dimensional reconstruction. Screw trajectory reconstruction with coronal and sagittal reconstruction is useful to evaluate the pedicle width and height.     

Morphometry of the thoracic and lumbar spine related to transpedicular screw placement for surgical spinal fixation

Vertebral transpedicular screws provide secure attachment for posterior spinal fixation devices. Screw design details, biomechanics, and implantation safety depend upon anatomic constraints, especially from the pedicle and body. Previous morphometric data were limited; thus, a retrospective study was undertaken using computerized axial tomograms (CT) of 91 vertebrae (T9-L5). In addition, eight cadaver vertebrae were CT scanned and then cut transversely to compare x-ray measurements with direct physical measurements. Measured parameters included pedicle width, pedicle length, angle of pedicle axis to sagittal plane, and transpedicular cortex-to-cortex chord length. Good correlation is shown to occur between CT scan and direct physical measurements of human vertebrae. Implications for spinal implant screw dimensions and safety of implantation are discussed. Comparison with previously available data is made.     

Anatomical considerations for cervical pedicle screw insertion: the use of multiplanar computerized tomography measurements in 122 consecutive clinical cases

Background contextSuccessful placement of pedicle screws in the cervical spine requires a sufficient three-dimensional understanding of pedicle morphology to allow accurate identification of the screw axis.PurposeThe goal of the present study was to assess morphologic trends from one level to the next with respect to linear and angular parameters associated with the subaxial cervical pedicles.Study design/settingWe evaluated the pedicle morphology of cervical spine using axial and sagittal computed tomography (CT) imaging. The C3–C7 vertebrae in 122 patients (610 vertebrae) were evaluated (age range, 14–93; mean, 48 years).MethodsThin cut (2.5 mm thickness) axial CT images were measured. Sagittal reconstructions were obtained using 1.25-mm thickness slices. The following pedicle parameters were assessed: pedicle width (PW, the mediolateral diameter of the pedicle isthmus, perpendicular to the pedicle axis), pedicle height (PH, rostro-caudal dimension of the pedicle determined on the sagittal image), maximal screw length (MSL, distance from the posterior cortex of the lateral mass to the anterior wall of the vertebral body along the pedicle axis), and pedicle transverse angle (PTA, angle between the pedicle axis and the midline vertebral body).ResultsThe overall mean PW and PH ranged from 4.7 to 6.5 mm and 6.4 to 7.0 mm, respectively. For both these parameters there was a trend toward increasing size proceeding caudally in the cervical spine. The mean PW and PH was greater in males than in females, and this difference was statistically significant at all levels (p<.0001). The overall mean MSL ranged from 29.9 to 32.9 mm. All intersections of the pedicle axis and the posterior cortex of the lateral mass were located at the most lateral portion of the lateral mass for the C3–C6 vertebrae. The overall mean PTA ranged from 37.8° to 45.3°. The overall mean PTA was approximately 44° from C3 to C6 and 37.8° at C7.ConclusionThe findings of our radiological anatomical study suggest that the preoperative CT scans of patients undergoing cervical transpedicular fixation should be thoroughly analyzed and close attention paid to the pedicle size and its angulation. The placement of cervical pedicle screws should be individualized for each patient and based on detailed preoperative planning.     

Axial computed tomography of the pedicle in the lower cervical spine

Using axial computed tomography (CT), we measured pedicle width, pedicle axis length, pedicle transverse angle, and distance between screw entry point and vertebrae midline in the cervical spines (C3-C7) of 40 patients. All measurements were greater in men than in women, and we noted significant sex differences at most levels of pedicle inner and outer widths (P < or = .05 or P < or = .01). Mean pedicle inner and outer widths for all levels and all patients ranged from 2.3 to 3.0 mm and from 5.0 to 6.0 mm, respectively. Mean distances between screw entry point and vertebrae midline ranged from 22.2 to 23.7 mm. Results of this study-along with axial CT measurements of individual pedicle diameter, pedicle transverse angle, and screw entry point-would be useful when considering and performing transpedicular screw fixation in the cervical spine.     

Analysis of the morphometric characteristics of the thoracic and lumbar pedicles

A total of 2,905 pedicle measurements were made from T1-L5. Measurements were made from spinal computerized tomography (CT) scan examinations and individual vertebral specimen roentgenograms. Parameters considered were the pedicle isthmus width in the transverse and sagittal planes, pedicle angles in the transverse and sagittal planes, and the depth to the anterior cortex in a line parallel to the midline of the vertebral body and along the pedicle axis. There was no significant difference between data obtained from CT scans and specimen roentgenograms. Pedicles were widest at L5 and narrowest at T5 in the transverse plane. The widest pedicles in the sagittal plane were seen at T11, the narrowest at T1. Due to the oval shape of the pedicle, the sagittal plane width was generally larger than the transverse plane width. The largest pedicle angle in the transverse plane was at L5. The posterolateral to anterolateral pedicle axis orientation in the transverse plane, seen at other levels throughout the thoracolumbar spine, reversed at T12. In the sagittal plane, the pedicles angled caudally at L5 and cephaladly from L3-T1. The depth to the anterior cortex was significantly longer along the pedicle axis than along a line parallel to the midline of the vertebral body at all levels with the exception of T12 and T11.     

The effect of pedicle screw instrumentation at a young age on upper thoracic vertebra and canal development

BACKGROUND CONTEXTPedicle screws are widely used in spinal surgeries. Pedicle screw fixation has shown better clinical effects than other techniques by providing steady fixation from the posterior arch to the vertebral body. However, there are several concerns about the impact of pedicle screw instrumentation insertion on vertebral development in young children, including early closure of the neurocentral cartilage (NCC). The effect of pedicle screw insertion in an early age on further growth of the upper thoracic spine is still unclear.PURPOSEThis study aimed to evaluate the impact of pedicle screw insertion on further growth of the upper thoracic vertebra and spinal canal.STUDY DESIGNA retrospective case study.PATIENT SAMPLETwenty-eight patients.OUTCOME MEASUREMENTSX-ray and CT parameters including length, height and area of the vertebrae and spinal canal were manually measured.METHODSTwenty-eight patients who underwent pedicle screw fixation (T1-T6) before the age of 5 years from March 2005 to August 2019 at Peking Union Medical College Hospital were recruited, and records were retrospectively reviewed. Vertebral body and spinal canal parameters were measured at instrumented and adjacent noninstrumented levels and compared using statistical methods.RESULTSNinety-seven segments met the inclusion criteria (average age at instrumentation 44.57 months, range from 23–60 months). Thirty-nine segments had no screws, and 58 had at least one screw. There was no significant difference between the preoperative and final follow-up values of the measurement of vertebral body parameters. No significant difference was observed between the growth rates in levels with or without screws in pedicle length, vertebral body diameter, or spinal canal parameters.CONCLUSIONPedicle screw instrumentation in the upper thoracic spine does not cause a negative effect on the development of the vertebral body and spinal canal in children younger than 5 years old.     

经伤椎椎弓根钉内固定治疗胸腰椎爆裂骨折

目的探讨经伤椎椎弓根钉固定治疗胸腰椎爆裂骨折的临床疗效。方法 58例胸腰椎爆裂骨折患者中36例行传统跨伤椎的4钉固定(A组),22例行经伤椎椎弓根5钉固定(B组)。结果 58例均获随访,时间7～32(13.5±5.4)个月。依据患者伤椎前缘高度、矢状面Cobb角、椎管正中矢状径、神经功能恢复进行临床疗效评价。伤椎前缘高度、矢状面Cobb角、椎管正中矢状径两组术后1周与术前比较差异均有统计学意义(P<0.01);但两组之间比较差异无统计学意义(P>0.05);术后6个月,椎前缘高度、矢状面Cobb角两组比较差异有统计学意义(P<0.05),椎管正中矢状径、神经功能评定两组比较差异无统计学意义(P>0.05)。结论经伤椎椎弓根固定是治疗胸腰椎爆裂骨折的有效方法,较传统跨伤椎固定能更好维持矫正效果。