下颈椎椎弓根螺钉内固定相关参数的解剖学和影像学测量

目的:测量成人下颈椎椎弓根相关径线,为临床应用下颈椎椎弓根螺钉内固定提供相关解剖参数.方法:成人干燥尸体颈椎C3～C7标本20具,分别用手工和CT测量椎弓根宽度、高度,从横断面CT图像上测量椎弓根的内部宽度、内部高度,从纵断面CT图像上测量椎弓根矢状角.随机在CT窒保存的100例成人患者的颈椎CT图像上测量椎弓根的宽度、自身长度和椎弓根通道全长、椎弓根内倾角.结果:下颈椎标本各节段椎弓根宽度、高度的手工测量值与CT测量值比较无统计学差异(P>0.05),椎弓根宽度小于高度;C3～C6节段CT测量椎弓根内部宽度平均为2.5～2.8mm,椎弓根内部高度平均为2.9～3.0mm,C7椎弓根的内部宽度和高度接近,约4.0mm;下颈椎标本CT测量椎弓根矢状角分别为C3 8.6°,C4 4.6°,C5-1.3.,C6-4.0°,C7-8.2°.100例成人下颈椎CT图像测量椎弓根宽度最小值为3.1mm(C3),最大值为9.3mm(C7),其中>3.5mm者为92.8%;椎弓根自身长度平均为19.1～20.5mm,椎弓根通道全长平均为33.2～35.0mm,椎弓根内倾角平均值C3～C5为43.2°～45.1°,C6为40.8°,C7为37.5°.结论:术前CT测量可为椎弓根准确置钉提供可靠的解剖参数,下颈椎椎弓根一般可接受直径3.5mm的螺钉同定.     

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.     

以枢椎椎弓峡部内上壁为解剖标志行枢椎椎弓根置钉的CT测量及临床应用

目的:探讨以枢椎椎弓根峡部内上壁为解剖标志的枢椎椎弓根螺钉置钉的可行性及安全性。方法:57例成人枢椎行三维CT重建,在三维重建图像上测量枢椎左右侧椎弓根的中部宽度L1和高度L2;以枢椎椎弓峡部内上壁为标志横断面确立左右侧的最外侧模拟进钉点B和最内侧模拟进钉点A到峡部距离;测量最佳进钉点S(经过枢椎椎弓根中部宽度连线的中垂线与峡部后侧皮质交点)到峡部内壁距离,分别测量A、B、S点横断面进钉角度最大置钉角度区间;冠状面上测量S点距离峡部内上壁距离;测量S点进钉最佳内倾角及上倾角。选择2007年10月～2011年7月收治的33例患者采用枢椎椎弓根峡部内上壁为标志实施枢椎椎弓根螺钉内固定术,其中新鲜齿状突骨折13例,陈旧性齿状突骨折10例,横韧带损伤伴寰枢椎脱位7例,寰椎骨折3例。观察手术中与枢椎椎弓根螺钉置钉相关的并发症,术后三维CT重建观察螺钉的位置。结果:CT横断面测量进钉点A、B、S到峡部的距离为1.75mm、9.01±0.62mm、5.77±0.53mm,S点置钉角度区间与A、B点置钉角度区间比较有显著性差异(P<0.05)。冠状面上S点距离峡部内上壁距离为4.30±0.49mm;S点进钉内倾角为30°、上倾角为26°时为最佳进钉角度。临床共置入枢椎椎弓根螺钉66枚,术中显露良好,未出现椎动脉、静脉丛损伤出血及脊髓、神经根损伤等并发症。术后三维CT复查显示所有枢椎椎弓根螺钉均未误入椎管或椎动脉孔,术中测量枢椎椎弓根螺钉进钉点横断面上与枢椎椎弓峡部内壁水平间距为5.44±0.72mm,冠状面上距离峡部内上壁为4.50±0.52mm,与术前S点测量值相比较均无显著性差异。结论:枢椎椎弓根与峡部存在恒定位置关系,以枢椎椎弓峡部内上壁为解剖参照行枢椎椎弓根置钉是安全可行的。     

前路经寰枢关节螺钉内固定术治疗寰枢关节不稳定的解剖学及临床研究

目的 为前路经寰枢关节螺钉内固定术提供临床解剖学依据.方法 在100对中国成人干燥寰、枢椎配对标本上,对与临床前路经寰枢关节螺钉内固定术相关的数据进行解剖学测量.并对11例创伤性寰枢椎不稳定患者施行了前路经寰枢关节螺钉内固定术,在齿状突与寰椎前结节后方置入颗粒状松质骨.结果 前路经寰枢关节螺钉内固定术冠状面上螺钉植入最小外偏角(5.5±2.0)度,最大外偏角(23.6±2.1)度,矢状面上螺钉植入最小后倾角(14.9±2.6)度,最大后倾角(25.6 ±2.5)度,内侧钉道距离(16.58±1.49)mm,外侧钉道距离(26.44±1.75)mln.11例患者中,1例颈脊髓完全损伤患者,术后1个月死于肺部感染.其余10例病例获得随访,时间7个月～3年,平均17个月,无椎动脉及脊髓损伤,所有病例获得骨性融合.结论 前路经寰枢关节螺钉内固定术,操作简便,损伤脊髓或椎动脉的风险较小,为寰枢椎不稳定患者提供了一种新的内固定治疗方法.     

Morphometric analysis using multiplanar reconstructed CT of the lumbar pedicle in patients with degenerative lumbar scoliosis characterized by a Cobb angle of 30° or greater

Object Although the anatomy of the thoracic pedicle in adolescent idiopathic scoliosis is well known, that of the lumbar pedicle in degenerative lumbar scoliosis is not. The morphometric differences between the pedicles on the concave and convex sides can result in an increased risk of malpositioned pedicle screws. The purpose of this study was to analyze the lumbar pedicle morphology in degenerative lumbar scoliosis using multiplanar reconstructed CT. Methods The study group comprised 16 consecutive patients (1 man and 15 women, mean age 70.9 ± 4.5 years) with degenerative lumbar scoliosis characterized by a Cobb angle of at least 30° who underwent preoperative helical CT scans. The CT data in DICOM format were reconstructed, and the following parameters were measured for each pedicle inside the curves: the inner cortical transverse pedicle width (TPWi) and outer cortical transverse pedicle width (TPWo) and axial angle, all on an axial plane, and the inner cortical minimum pedicle diameter (MPDi) and outer cortical minimum pedicle diameter (MPDo) and cephalocaudal inclination of the pedicle, all on the plane perpendicular to the pedicle axis. The cortical thickness and cortical ratio of the pedicles on the axial plane and the plane perpendicular to the pedicle axis were calculated. Data were obtained for a total of 124 pedicles; L-1, 26 pedicles in 13 patients; L-2, 32 pedicles in 16 patients; L-3, 32 pedicles in 16 patients; L-4, 28 pedicles in 14 patients; and L-5, 6 pedicles in 3 patients. Results Among the target vertebrae, the TPWi, MPDi, and MPDo were significantly smaller and the axial angle was significantly larger on the concave side than on the convex side (TPWi, 6.37 vs 6.70 mm, p < 0.01; MPDi, 5.15 vs 5.67 mm, p < 0.01; MPDo, 7.91 vs 8.37 mm, p < 0.05; axial angle, 11.79° vs 10.56°, p < 0.01). The cortical ratio of the pedicles was larger on the concave side than on the convex side (on the axial plane, 0.29 vs 0.26, p < 0.05; on the plane perpendicular to the pedicle axis, 0.36 vs 0.32, p < 0.01). These differences were most evident at L-4. Conclusions This study demonstrated lumbar pedicle asymmetry in degenerative lumbar scoliosis. The authors speculate that these asymmetrical changes were attributed to the remodeling caused by axial load imbalance and the limited space available for pedicles on the concave side. On the concave side, because of the narrower pedicle diameter and larger axial angle, surgeons should carefully determine screw size and direction when inserting pedicle screws to prevent possible pedicle wall breakage and neural damage.     

骶髂关节经皮拉力螺钉固定钉道参数的解剖学测量

目的 为经S_1椎弓根水平骶髂关节拉力螺钉固定术提供应用解剖学依据.方法 2008年6月至2009年7月收集50个成人骨盆的螺旋CT扫描数据,重建骨盆三维模型,模拟经皮托力螺钉固定.测量S_1椎弓根的宽和高、骶髂关节拉力螺钉的进针点和进针方向、进针点至S_1椎体对侧前皮质和髂后上棘的距离.结果 S_1椎弓根的宽和高分别为(20.43±1.63)mm和(20.26±0.99)mm;2枚螺钉的进针点均在髂前上棘和髂后上棘的连线上方,至髂后上棘的距离分别为(49.87±6.80)mm和(51.11±7.15)mm.螺钉平行进入S_1椎弓根,与髂骨翼后外侧面垂直,与冠状面和欠状面的夹角分别为18.35°±5.20°和77.62°±3.98°.进针点到S1椎体对侧前皮质的距离分别为(76.08±4.32)mm和(77.62±3.98)mm.骶髂关节拉力螺钉的长度、S_1椎弓根的高度和宽度、进针点到髂后上棘的距离、进针点与冠状面的夹角在男女之间差异有统计学意义(P<0.05).结论 正常成人在S_1椎弓根水平均町置入2枚直径为6.5 mm的拉力螺钉,钉道参数的解剖学测量为骶髂关节拉力螺钉固定手术导航模板的设计提供了理论基础.     

下颈椎椎弓根螺旋CT扫描的三维重建及测量

目的 评价应用多层螺旋CT扫描三维重建技术测量下颈椎椎弓根相关参数的可行性. 方法 8具成年男性颈椎标本经螺旋CT扫描后,把信息传送至随机工作站(Silicon Graphics O2),结合下颈椎榷弓根置钉的参数需求,进行三维重建[容积成像(VR)和多平面重组(MPR)]后测量椎弓根各个相关数据.然后对这些数据进行分析. 结果本组下颈椎椎弓根的外展角平均为42.02°±7.55°,C_7最小(35.63°±6.34°),C_4最大(46.94°±5.69°);头倾角平均为76.30°±12.01°,C_3最小(72.93°±6.57°),C,最大(81.27°±13.34°);入点至下关节缘距离平均为(11.23±1.78)mm,C_3最小[(10.54±1.25)mm],C_6最大[(12.05±1.40)mm];入点至侧块外缘距离各椎体相筹较大,平均为(2.65±1.21)mm,C_4最小[(1.69±0.81)mm],C_7最大[(3.74±0.99)mm];入点至椎体前缘距离各椎体差异较小,平均为(31.42±2.13)mm;椎弓根皮质骨高度平均为(8.43±1.30)mm,宽度半均为(5.54±1.26)mm;椎弓根松质骨高度平均为(3.69±1.19)mm,宽度平均为(2.67±1.15)mm;椎弓根皮质高度一般大于宽度,C_4内径最小,C_7内径最大. 结论 VR、MPR重建图像可满足椎弓根参数测量要求,其所测量的下颈椎椎弓根参数可满足经椎弓根手术的术前评估需求;下颈椎椎弓根变异较大.     

Internal morphology of human cervical pedicles

STUDY DESIGN: The internal architecture of cervical spine pedicles was investigated by thin sectioning and digitization of radiographic images. OBJECTIVES: To provide quantitative information on the internal dimensions and cortical shell thicknesses of the middle and lower cervical pedicles. SUMMARY OF BACKGROUND DATA: Although there have been a number of studies presenting data on the external dimensions of the cervical pedicle, little is known regarding its internal architecture and cortical shell thickness along the pedicle axis. METHODS: Twenty-five human cervical vertebrae (C3-C7) were secured to a thin-sectioning machine to produce three 0.7-mm-thick pedicle slices along its axis. Plain radiographs of the pedicle slices were scanned and digitized to facilitate measurement of the internal dimensions. Computer software was specifically developed to determine the external dimensions (i.e., pedicle height and width) and the internal dimensions (i.e., cortical shell thicknesses of the superior, inferior, lateral, and medial walls and the cancellous core height and width) of cervical pedicles. RESULTS: Superior and inferior wall cortical thicknesses of pedicle thin slices were similar, whereas the lateral wall cortical thickness was significantly smaller than the medial wall thickness. The medial cortical shell (average value range: 1.2-2.0 mm) was measured to be 1.4 to 3.6 times as thick as the lateral cortical shell (average value range: 0.4-1.1 mm). When medial and lateral cortical thicknesses were normalized for external dimensions, the combined cortical shell thickness was thinnest at C7 (average value range: 18. 6-25.6% of the external width), and this result was statistically significant when compared with other vertebral levels. CONCLUSIONS: The cervical pedicle is a complex, three-dimensional structure exhibiting extensive variability in internal morphology. Characteristics of the cervical pedicle at different spinal levels must be noted before transpedicular screw fixation.     

寰椎“椎弓根”三维CT重建测量及分型的临床意义

目的:研究通过三维CT重建测量正常状态下寰椎"椎弓根"形态及其相关解剖学数据,对其进行分类并探讨其临床意义。方法:选取150例正常成人志愿者,年龄18～52岁(平均32.3岁),排除相关上颈椎疾患,尤其局部骨性增生明显者。对其寰枢椎进行螺旋CT扫描,在CT三维多平面重建下,取经枢椎下关节突中点矢状线延长线与寰椎椎动脉沟底部下2mm处后弓的交点为A点,同时建立通过椎动脉沟底部下2mm处的寰椎横切面图,取寰椎后弓移行为侧块处椎动脉孔内壁与椎管外壁连线的中点为B点,AB连线的延长线与寰椎前弓的交点为C点,AC连线即为寰椎椎弓根钉道。取经AC连线建立寰椎椎弓根通道的矢状面切图。测量寰椎双侧椎弓根各主要解剖参数:寰椎椎弓根的上倾角,椎动脉沟底椎弓根厚度(H1),寰椎椎弓根最大厚度;根据H1数值的大小分型,探讨各分型与椎弓根钉选择的相符性。结果:钉道椎动脉沟底处骨质厚度为4.10±1.17mm。根据H1数值的大小,以直径4.00mm和3.50mm的螺钉为参照,分为四型:正常型:H1>4.00mm(92例,61.3%);相对狭窄型:3.500.05)。正常型和相对狭窄型建议采用"椎弓根"螺钉技术。狭窄型和无椎弓根型者采用侧块螺钉技术。结论:三维CT重建能够准确提供寰椎椎弓根的解剖学形态、解剖学参数,根据寰椎椎动脉沟处骨质的高度进行分类,可以较好的指导寰椎后路"椎弓根"及侧块螺钉固定技术的选择及螺钉直径的选择。     

胸椎经关节突关节椎弓根螺钉固定的可行性研究

 目的明确胸椎后路经关节突关节椎弓根螺钉固定的解剖学可行性和技术参数.为临床应用提供参考。方法取 20具胸椎标本.仔细解剖胸椎的后侧和前侧方.以清楚地暴露胸椎椎板和椎弓根。以椎板下缘向上、外缘向内各 7 mm为进钉点.在 T_1.2、T_5.6、T_9.10直视下置入经关节突关节椎弓根螺钉.通过直接的置钉和 CT重建.观察胸椎后路经关节突关节椎弓根螺钉实际置钉的可行性.测量经关节突关节椎弓根螺钉内固定进钉角度和钉道长度。结果所有胸椎后路经关节突关节椎弓根螺钉均由上位胸椎下关节突经关节突关节.进入下位胸椎的椎弓根.成功置入下位胸椎的椎体内。重建 CT测量发现螺钉在横断面的外倾角度为 2.1°±0.7°.在矢状面的尾倾角度为 41.4°±3.2°.在各节段间略有不同.但差异无统计学意义。平均的螺钉钉道长度为(40.6±4.9) mm.钉道长度由上胸椎向中、下胸椎呈逐渐增加趋势.差异有统计学意义(F=74.09, P<0.01)。结论胸椎后路经关节突关节椎弓根螺钉具有解剖学可行性.可以作为胸椎椎弓根螺钉固定的一种补充内固定方法.但置钉时要求较高的准确性。     

Is the 4 mm height of the vertebral artery groove really a limitation of C1 pedicle screw insertion?

Purpose

To explore the feasibility and effectiveness of C1 pedicle screw fixation in patients whose atlas vertebral artery groove (defined as the C1 pedicle) height is less than 4 mm, but with a medullary canal.

Methods

From January 2010 to January 2013, 7 patients (6 males, 1 female) with atlantoaxial instability whose C1 pedicle height was less than 4.0 mm on one or both sides were treated by C1 pedicle screw fixation at our institution. Thirteen of the 14 C1 pedicles were less than 4.0 mm in height, but all had a medullary canal. Patients were followed up at regular intervals. Postoperative computed tomography (CT) scans were performed to assess if C1 pedicle screw placement was successful. Clinical outcomes were evaluated according to postoperative complications, the American Spinal Injury Association grading system, and bone graft status.

Results

Thirteen C1 pedicles with a height less than 4.0 mm were inserted by 13 3.5- or 4.0-mm-diameter pedicle screws, and one C1 pedicle whose height was 4.1 mm was inserted by a 4.0-mm-diameter pedicle screw. In addition, 14 pedicle screws were inserted in the axis. The mean follow-up period was 23 (range 8–38) months. No neurologic or vascular complications occurred in any of the seven patients. Postoperative CT three-dimensional reconstruction images showed that all 14 pedicle screws were inserted in the C1 pedicles without destruction of the atlas pedicle cortical bone. All patients demonstrated bony fusion 6 months postoperatively.

Conclusion

If there is a medullary canal in the C1 pedicle, a 3.5- or 4.0-mm-diameter pedicle screw can be safely inserted into the atlas and C1 pedicle screw fixation can be performed without any impact on fixation stability and clinical efficacy, even if the C1 pedicle height is less than 4.0 mm.     

后路寰枢椎侧块关节融合器置入的临床应用解剖

目的了解国人寰枢椎侧块关节周围血管、神经的解剖关系,为后路寰枢椎侧块关节融合器准确、安全置入提供解剖学依据。方法选用成人尸体标本20具,冠状面上观察寰枢椎侧块关节后缘周围解剖关系;平枢椎侧块上关节面后缘测量C1、2间椎动脉内缘至颈髓硬脊膜外缘的距离,确定手术冠状位的"安全操作空间";测量枢椎下关节突后内缘的纵垂线与枢椎椎弓上缘交点(G点)至枢椎椎弓根上缘中线延长线的水平距离,确定手术切入点。结果 "安全操作空间"为(19.72±1.84)mm,水平距离为(2.23±0.45)mm。寰枢椎后膜下的静脉丛主要集中在寰枢椎侧块关节的外缘、上方和内缘,其下方尤其枢椎椎弓根上缘的静脉丛稀疏。位于寰椎椎弓根下方、寰枢椎侧块关节内上侧的C2神经根,距颈硬脊膜外缘5~7 mm处膨大成颈神经节,并发出前、后支。结论 G点恒定在枢椎椎弓根上缘中线延长线的内侧2.5 mm处,以此点向外水平旁开2.5 mm,向上推开寰枢后膜,内上骨膜下剥离并沿枢椎椎弓根上缘中线一并剥离枢椎椎弓根骨膜和寰枢椎侧块关节囊,即可显露寰枢椎侧块关节并置入融合器。以此入路在"安全操作空间"内置入融合器,可避免切开寰枢后膜而损伤血管和神经,保证了手术的安全。     

Morphology of the atlas pedicle revisited: a morphometric CT-based study on 120 patients

Purpose

To quantify the dimensions of the atlas pedicles and to analyze the relationship between extra medullary height (EMH) with intra medullary height (IMH) of the atlas pedicle.

Methods

The images of the patients who had CT scanning and three-dimensional (3D) reconstruction involving atlantoaxial complex between June 2011 and April 2012 and meet our inclusion criteria were studied retrospectively. After reformatting the original images, the EMH and IMH of the atlas pedicles were measured.

Results

Extra medullary height and IMH were, respectively, 4.83 ± 1.13 and 1.29 ± 1.10 mm for males and 3.75 ± 0.93 and 0.60 ± 0.83 mm for females, with statistical difference (P < 0.05). EMH and IMH had some correlation (correlation coefficient r = 0.804) but showed a large variability. Of 240 pedicles of 120 cases, 47.92 % (115 pedicles) were ≥1 mm; 12.08 % (29 pedicles) were between 0 and 1 mm; and 40 % (96 pedicles) were 0.

Conclusion

The EMH and the IMH of the atlas pedicles were measured by using CT images of the atlas, providing anatomic parameters for surgery. They showed a certain correlation but with a high variability. C1 pedicle screw fixation was well performed when the medullary canal was ≥1 mm, but the surgical procedure should be careful when it was between 0 and 1 mm, and avoided when there was no medullary canal in the atlas pedicle! So 3D CT reconstruction should be conducted to obtain data and establish individualized fixation strategy preoperatively.     

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。     

基于三维CT重建的寰椎椎弓根解剖学测量及临床意义

目的：研究螺旋CT三维重建测量人正常状态下寰椎椎弓根形态及其相关解剖学数据。方法：选取150例正常成人志愿者,年龄18—52岁（平均36．3岁）,对其寰枢椎进行螺旋CT扫描,三维重建后观察椎弓根形态,并测量其双侧椎弓根各主要解剖数值：椎弓根高度、宽度、进钉点距后正中矢状面距离、椎根弓内倾角及上倾角。结果：根据椎弓根高度分为正常型;相对狭窄型;狭窄型;无椎弓根型。正常寰椎椎弓高度（4．10±1．17）mm,上倾角（8．24±1．31）°,内倾角（6．53±2．35）°,椎弓根宽度（8．24±1．31）mm,长度（28．73±1．66）mm,进钉点距后正中矢状面距离（19．36±1．27）mm。结论：三维CT重建能够全面观察寰椎影像解剖的立体结构,准确提供寰椎椎弓根的解剖学形态、解剖学参数,为寰椎椎弓根螺钉内固定技术提供解剖学依据。     

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.     

Value of intraoperative true lateral radiograph of C2 pedicle for C1-2 transarticular screw insertion.

BACKGROUND CONTEXT: Transarticular C1-2 screws are widely used in posterior cervical spine instrumentation. Injury to the vertebral artery during insertion of transarticular Cl-2 screw remains a serious complication. Use of a computer-assisted surgery system decreases this complication considerably. However, this system encounters problems in ensuring complete accuracy because of positional variations during preoperative and intraoperative imaging generation. Therefore, intraoperative fluoroscopy still is one of the commonly used methods to guide insertion of transarticular Cl-2 screw. Evaluation of a true lateral radiographic view of the C2 pedicle for screw trajectory during C1-2 transarticular screw insertion may help to minimize this potential complication. PURPOSE: To evaluate the value of intraoperative true lateral radiograph of the C2 pedicle for screw trajectory during C1-2 transarticular screw insertion. STUDY DESIGN: To compare the height of the C2 pedicle area allowing instrumentation on true lateral view radiograph of the C2 pedicle and computed tomographic (CT) scan with multiplanar reconstruction. METHODS: Twenty embalmed human cadaveric cervical spine specimens were used to insert a total of 40 C1-2 transarticular screws using Magerl and Seemann technique. One side of the C2 transverse foramen was filled with radiopaque material (lead oxide) to simulate the artery and to demarcate the danger zone for better visualization on radiography. Measurements and calculation of the mean and standard deviation of the height of the area allowing instrumentation of the C2 pedicle were done on true lateral view radiograph of the C2 pedicle, the sagittal and 30 degrees sagittal views relative to the frontal plane passing exactly through the center of the C2 pedicle of CT scans. Student t test was applied to calculate the statistical significance of measured values. Statistical significance was defined as por=.36. Using sagittal CT scan views, the height of pedicles was 7.71+/-0.7 mm (right) and 7.58+/-1.01 mm (left), p>or=.23. On 30 degrees sagittal CT scan views, the height of pedicles was 7.84+/-1.00 mm (right) and 7.76+/-1.02 mm (left), p>or=.27. The p value was >or=.78, >or=.56, and >or=.49 for true lateral radiographic view and sagittal CT scan view, true lateral radiographic view and 30 degrees sagittal CT scan view, and sagittal CT scan view and 30 degrees sagittal CT scan views, respectively. On lateral view of cervical spine, the decline angle of the transarticular screw was 51.3+/-0.50 degrees (right) and 50.68+/-0.41 degrees (left), p>or=.17. Mean decline angle was 51+/-0.43 degrees . On the anteroposterior (AP) view, radiograph median angle was 6.87+/-0.53 degrees (right) and 6.0+/-0.59 degrees (left), p>or=.25. Mean median angle was 6.44+/-0.62 degrees. CONCLUSIONS: True lateral radiographic views of the pedicles provide useful information for defining screw trajectory intraoperatively. Using this view along with AP and lateral view of cervical spine and preoperative three-dimensional CT scan may narrow the margin of error in this delicate area.     

胸椎椎弓根髓腔内径CT分型在严重僵硬性脊柱畸形矫形中的临床意义

目的探讨基于胸椎椎弓根髓腔内径CT分型在对严重僵硬性脊柱畸形行经后路全脊椎切除术(posterior vertebral column resection,PVCR)矫形徒手植钉中的临床意义。方法 2004年10月-2010年7月对56例严重僵硬性脊柱畸形患者一期行PVCR矫形,T2～12共植入1 098枚椎弓根螺钉。于CT片测量胸椎椎弓根髓腔内径,并划分为4个区间:区间1(0～1.0 mm),区间2(1.1～2.0 mm),区间3(2.1～3.0 mm),区间4(3.1 mm);对各区间椎弓根螺钉植钉成功率进行统计学分析。根据结果将无统计学意义的区间合并,再次行统计学分析。根据Lenke的椎弓根形态学分型,行各型植钉成功率统计学分析。结果 1 098枚胸椎椎弓根螺钉中,826枚(75.23%)植钉成功。根据髓腔内径分区,除区间3与区间4椎弓根植钉成功率比较差异无统计学意义(χ2=2.540,P=0.111)外,其余各组间比较差异均有统计学意义(P0.008)。区间3、4合并后,区间1、2、3植钉成功率分别为35.05%、65.34%、88.32%,两两比较差异均有统计学意义(P0.017)。根据Lenke的椎弓根形态学分型,A、B、C、D型植钉成功率分别为82.31%、83.40%、80.00%、30.28%,D型植钉成功率显著低于其余各型(P0.008),其余各型间差异均无统计学意义(P0.008)。基于胸椎椎弓根髓腔内径CT分型标准,Ⅰ型椎弓根占总数的17.67%,凹、凸侧椎弓根分别为24.59%、10.75%;Ⅱa型占总数的16.03%,凹、凸侧分别为21.13%、10.93%;Ⅱb型占总数的66.30%,凹、凸侧分别为54.28%、78.32%。各型凹、凸侧分布比较差异均有统计学意义(P0.001)。结论基于胸椎椎弓根髓腔内径提出了量化分型标准,Ⅰ型为无髓腔型,椎弓根内径0～1.0 mm;Ⅱ型为有髓腔型,其中Ⅱa型椎弓根内径为1.1～2.0 mm,Ⅱb型2.1 mm。该分型标准可在行PVCR时指导徒手植入胸椎椎弓根螺钉,但其有效性需进一步临床观察验证。     

后路凸凹侧双棒同步矫形在青少年特发性脊柱侧凸矫治中的应用

目的 探讨后路凸凹双侧矫形棒同步矫形技术在青少年特发性脊柱侧凸(AIS)外科矫治中的应用价值及疗效.方法 2006年2月至2008年8月采用后路凸凹侧双棒同步矫形技术治疗AIS 48例,其中男性16例,女性32例;年龄11～24岁,平均17.1岁.Lenke分型:Ⅰ型17例、Ⅱ型9例、Ⅲ型14例、Ⅳ型8例.行选择性胸弯融合27例,非选择性融合21例.观测手术前后冠状Cobb角、顶椎偏距、顶椎旋转、躯干偏移、尾端融合椎旋转、倾斜角、椎间角、矢状面平衡变化,评价侧凸矫正效果及脊柱平衡状况.结果 术后随访12～27个月,平均15.1个月.选择性融合患者末次随访胸、腰弯Cobb角平均矫正率分别为(76±11)%、(72±9)%.非选择性融合术患者末次随访胸、腰弯Cobb角平均矫正率分别为(74±15)%、(69±9)%.所有病例尾侧保留脊柱活动节段平均4.4个.1例因术中定位错误发生近端交界性后凸行翻修术.其余病例末次随访无脊柱失代偿,无假关节形成、神经损伤等并发症.结论 应用后路凸凹双侧矫形棒同步矫形治疗AIS,有助于提高矫形效果,重建和维持脊柱平衡,减少尾侧融合节段.     

前后路联合手术治疗齿状突骨折畸形愈合伴难复性寰枢椎脱位

目的:探讨经口前路松解齿状突部分切除与后路复位固定融合治疗齿状突骨折畸形愈合伴难复性寰枢椎脱位的疗效。方法:2008年1月～2011年1月我院共收治7例齿状突骨折畸形愈合致难复性寰枢椎脱位患者,男5例,女2例,年龄21～51岁,平均36.4岁。术前神经功能JOA评分为5～9分,平均7.3±2.1分;脊髓有效空间(space available for the cord,SAC)为4～12mm,平均8.34±3.68mm。均行经口前路松解、齿状突部分切除,一期后路寰枢椎椎弓根螺钉系统进一步提拉复位、固定、融合术,术后观察神经功能改善情况,并行X线、CT、MRI检查观察复位及植骨融合情况。结果:手术时间280～360min,平均310min。术中出血510～930ml,平均670ml。术中无脊髓神经损伤;1例术中置入枢椎椎弓根螺钉时损伤椎动脉,经原钉道拧入螺钉后完成止血,术后随访无椎动脉损伤的临床表现;1例术中置入寰椎椎弓根螺钉时寰椎后弓下壁破裂,未改变钉道,继续沿椎弓根方向置入螺钉,术后随访无寰枢椎的再失稳和移位。所有患者均获得满意复位。随访9～36个月,平均19.6个月。均在术后6个月获得骨性融合,随访期间未发现螺钉松动、移位、断裂,无寰枢椎再移位、失稳现象。末次随访时,JOA评分为11～15分,平均13.1±2.1分,与术前比较有统计学差异(P<0.05),改善率为78.8%～93.5%,平均87.4%;末次随访时的SAC为11～18mm,平均14.78±2.15mm,与术前比较明显增大(P<0.05)。结论:对于齿状突骨折畸形愈合伴难复性寰枢椎脱位患者,经口咽前路松解齿状突部分切除与后路复位固定融合术可获得好的复位效果,近期疗效满意。