颈椎椎弓根技术在下颈椎疾患应用的临床疗效观察

[目的]探讨颈椎椎弓根内固定技术在下位颈椎疾患应用的临床疗效。[方法]回顾2000年8月~2007年8月对118例患者,置入490枚椎弓根螺钉治疗下颈椎疾患,其中颈椎骨折脱位81例,颈椎病合并椎管狭窄21例,颈椎黄韧带骨化11例,颈椎后突畸形2例,强直性脊柱炎3例。术前应用图像存储传输系统(简称PACS),采用X线片及64排CT片,对患者下位颈椎椎弓根的冠状位、矢状位、横断位进行精确测量,得出椎弓根的长度、宽度、高度、向内侧倾斜、向头侧倾斜角度的数据值,以指导术中选钉及置钉。术中应用自行研制的颈椎椎弓根定位导向器,准确定位入钉点及角度,打孔、置钉、固定。[结果]术后102例患者获13~65个月随访,平均随访时间18.95个月。采用JOA评分标准[1],结果:优82例,良15例,可3例,差2例,优良率95.01%。术后X线及CT示固定节段稳定,颈椎椎体高度和生理曲度维持良好,内固定位置良好,无植骨块脱出或钢板、螺钉松动、断裂等并发症,无脊髓及椎动脉损伤。2例患者植骨块吸收未融合,融合率为97.04%。[结论]下颈椎椎弓根螺钉技术是相对安全的操作,可用于需从后路固定的颈椎疾患病例,可维持良好的颈椎生理曲度,远期临床效果满意。     

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。     

Pitfalls in computed tomography of the cervical and lumbar spine

In 10 patients, evaluated by computed tomography studies of the spine, radiological findings alone may have led to misinterpretation of the clinical condition. Five patients demonstrated CT findings of cervical disc herniation or protrusion, while clinical examination resulted in the diagnosis of neuralgic amyotrophy. In contrast, 3 patients with clinical signs of compression of lumbar nerve roots had negative findings in CT studies of the lumbar discs. Additional slices at the level of the vertebral body, however, demonstrated free sequestration of disc substance. Two patients with signs of compression of cervical roots had normal CT findings, but extensive disc herniation was present at surgery.     

Management of fracture-dislocation of the lower cervical spine with the cervical pedicle screw system

INTRODUCTION

Usually, cervical pedicle screw fixation has been considered too risky for neurovascular structures. The purpose of this study was to investigate the method and efficacy of the cervical pedicle screw system for fracture-dislocation of the cervical spine because of its rigid fixation.

PATIENTS AND METHODS

A prospective study was conducted involving 48 patients with cervical spine fracture-dislocation who underwent cervical pedicle screw fixation surgery between January 2003 and January 2007. All patients had various degrees of cord injury, and they were classified according to the American Spinal Cord Injury Association (ASIA) Impairment Scale: 18 cases were grade A, 15 grade B, 10 grade C, and 5 grade D.

RESULTS

Six months after the operation, all patients had achieved solid bony fusion and stable fixation of the related segments. Thirty patients with incomplete spinal cord injury improved their ASIA Impairment Scale classification by 1 to 2 grades after the operation. Eighteen patients with complete spinal cord injury had no improvement in neural function. However, nerve root symptoms such as pain and numbness were alleviated to some extent.

CONCLUSIONS

The cervical pedicle screw system is an effective and reliable method for the restoration of cervical stability. Sufficient pre-operative imaging studies of the pedicles and strict screw insertion technique should be emphasised.     

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。     

A new cervical spine clearance protocol using computed tomography

OBJECTIVE: The purpose of this study was to assess a cervical spine clearance protocol for blunt trauma patients using helical computed tomographic (CT) scan of the cervical spine (C-spine). METHODS: A protocol using CT scan of the C-spine was implemented and the first 6 months of use reviewed. Patients requiring a CT scan of the head had the C-spine evaluated by lateral C-spine radiography and a helical CT scan. Patients without indication for CT scan of the head had the C-spine evaluated by three-view radiography (anteroposterior, lateral, and odontoid) with selective CT scan of the C-spine for imaging areas not well visualized or those with abnormalities identified by radiography or by clinical examination alone. RESULTS: Three hundred twenty-four patients were admitted to the trauma center after blunt trauma during the first 6 months of protocol implementation. Head CT scans were obtained in 158 patients and lateral cervical spine radiography in conjunction with helical CT scanning evaluated the C-spine. The other 166 patients had the cervical spine cleared by three-view radiography series or by clinical examination alone. For patients in whom a head CT scan was not indicated, CT scanning was used only when plain radiographs failed to adequately visualize the entire C-spine. A total of 15 injuries (4.6% of the group) were detected. Seven injuries were suspected or detected by lateral plain radiographs and confirmed by CT scan. Six patients had an injury not detected by radiography but diagnosed by CT scan, and one patient had a false-positive radiograph. Of the remaining two injuries, one was diagnosed by magnetic resonance imaging and the other by CT scan outside of the protocol. Lateral plain radiographs alone failed to detect 46% (n = 6) of all injuries. CONCLUSION: In our series, the selective use of helical CT scanning with plain radiography increased the accuracy with which cervical spine injury was detected from 54% to 100%. The protocol allowed for more rapid evaluation in many patients as well. We recommend that practice guidelines include the use of helical CT scan of the entire C-spine as the diagnostic procedure for those blunt trauma patients undergoing CT scanning of the head.     

Yield of computed tomography of the cervical spine in cases of simple assault

BackgroundComputed tomography (CT) of the cervical spine (C-spine) is routinely ordered for low-impact, non-penetrating or “simple” assault at our institution and others. Common clinical decision tools for C-spine imaging in the setting of trauma include the National Emergency X-Radiography Utilization Study (NEXUS) and the Canadian Cervical Spine Rule for Radiography (CCR). While NEXUS and CCR have served to decrease the amount of unnecessary imaging of the C-spine, overutilization of CT is still of concern.MethodsA retrospective, cross-sectional study was performed of the electronic medical record (EMR) database at an urban, Level I Trauma Center over a 6-month period for patients receiving a C-spine CT. The primary outcome of interest was prevalence of cervical spine fracture. Secondary outcomes of interest included appropriateness of C-spine imaging after retrospective application of NEXUS and CCR. The hypothesis was that fracture rates within this patient population would be extremely low.ResultsNo C-spine fractures were identified in the 460 patients who met inclusion criteria. Approximately 29% of patients did not warrant imaging by CCR, and 25% by NEXUS. Of note, approximately 44% of patients were indeterminate for whether imaging was warranted by CCR, with the most common reason being lack of assessment for active neck rotation.ConclusionsCervical spine CT is overutilized in the setting of simple assault, despite established clinical decision rules. With no fractures identified regardless of other factors, the likelihood that a CT of the cervical spine will identify clinically significant findings in the setting of “simple” assault is extremely low, approaching zero. At minimum, adherence to CCR and NEXUS within this patient population would serve to reduce both imaging costs and population radiation dose exposure.     

Distribution patterns of transforaminal injections in the cervical spine evaluated by multi-slice computed tomography

Transforaminal injections are sometimes used for the diagnosis and treatment of painful conditions in the lumbar and to a lesser degree in the cervical spine. The technique is most often used when investigating/treating radiculopathy caused by degenerative disease. But how selective are the nerve root blocks? What possible structures other than the intended nerve root are affected from such injections? This study was undertaken in order to try to answer these questions, as no study focusing on the possible spread from the transforaminal selective nerve root blocks in the cervical spine has been performed earlier. In three groups of patients, each group including three patients, we injected three different volumes (0.6, 1.1 and 1.7 ml) with a transforaminal technique in the cervical spine. In all the injections, a small amount of contrast media was added. The spread of the injections were then investigated using multi-slice computed tomography with reconstructions. The imaging revealed a possible effect on other nerve roots than the intended ones when a larger volume was used for the root blocks. The spread was related to the injected volume as well as to local anatomy (size of foraminal area). In this study, only 0.6-ml injections could be accepted for being selective enough for diagnostic investigations.     

Radiological studies on the best entry point and trajectory of anterior cervical pedicle screw in the lower cervical spine

Objective

To explore the best entry point and trajectory of anterior cervical transpedicular screws in the lower cervical spine by radiological studies, and provide reference for clinical application.

Methods

Fifty patients were scanned by computed tomography and confirmed no obvious defect of the cervical spine. On horizontal axis, camber angle (α) and axial length (AL) were measured from C₃ to C₇. On sagittal view, the cranial or caudal angle (β) and sagittal length (SL) were also measured from C₃ to C₇. On the sagittal and horizontal planes vertebrae were respectively divided into four areas, ordered 1–4, on the anterior side of the pedicle. The areas and angles of pedicle intersect into the vertebral body were recorded. We inserted six anterior pedicle screws into the lower cervical spine of three patients by this technique.

Results

On transverse plane, camber angle (α) of C₃–C₅ increased gradually, while it decreased from C₅ to C₇. On sagittal view, C₃ and C₄ pedicles showed cranial tilting, while C₅ to C₇ were caudally tilted. AL and SL values increased gradually from C₃ to C₇. The number of the intersections of C₃–C₇ in each area was also different. Six pedicle screws of three cases were inserted into the lower cervical spine with proper placement and no complications.

Conclusion

Anterior transpedicular screw (ATPS) is a theoretically feasible option for internal fixation. The technique described in this paper was subsequently used in three patients without complication. Future improvement of ATPS insertion remains necessary for this technically demanding procedure.     

Ethnic differences in pedicle and bony spinal canal dimensions calculated from computed tomography of the cervical spine: a review of the English-language literature

Purpose

The aims of this study were to review published data on pedicle dimensions and bony spinal canal diameters calculated from CT examinations of the cervical spine through the English-language literature and analyze these data for ethnic disparities and similarities.

Materials and methods

The authors reviewed the literature on “pedicle” and “spinal canal” by conducting a bibliographic search using PubMed, Ovid MEDLINE, and Science Direct from January 1985 to December 2010. After evaluating all of the selected abstracts, we ultimately selected 19 studies involving living subjects: 12 studies on pedicle dimensions and 7 on spinal canal diameters. The four parameters, pedicle width (PW), pedicle transverse angle (PTA), anterior-posterior diameter of the spinal canal (APD), and transverse diameter of the spinal canal (TD), were analyzed at the relevant levels from C3 to C7. In addition, the values for pedicle dimensions and spinal canal diameters in the European/American populations were compared using the data from Asian populations as a baseline.

Results

The smallest mean PW was found at C4 in the male (5.1 mm) and female populations (4.1 mm); the largest mean PW was found at C7 in both male (7.7 mm) and female populations (7 mm). The PW in males was greater than in females at the majority of levels. The smallest mean PTA was found at C7 in both male (33.4°) and female populations (33°); the largest mean PTA was found at C4 in both male (53.2°) and female populations (52.1°). The overall PW, PTA, APD, and TD ratio of European/American to Asian populations was 91.4–98.8, 99.6–106.2, 110.7–122, and 100–108.3 %, respectively.

Conclusion

Although our cervical spine CT data were suggestive of possible ethnic differences in spinal canal morphology, our analysis failed to identify significant ethnic disparity in pedicle dimensions despite potential differences in physique between populations.     

下颈椎前路椎弓根螺钉最佳进钉点和进钉方向的影像学研究及其临床运用

目的:通过影像学研究下颈椎前路椎弓根螺钉置入的最佳进钉点及进钉方向,为临床运用提供依据。方法:选取2008年1月至2010年12月行颈椎CT扫描、无明显下颈椎畸形的完整影像学资料50例,其中男27例,女23例;年龄38～83岁,平均58.5岁。在椎弓根水平轴位像上,分别测量C3-C7前路下颈椎椎弓根轴线的外倾角(α)、椎体前缘经椎弓根中轴线到侧块后缘的距离(AL);将椎体前缘等分为4个区,从所测量的椎弓根对侧开始记为1～4区,记录椎弓根轴线与椎体前缘交点所在的区域。在椎弓根矢状轴位像上,分别测量C3-C7椎弓根轴线的头倾或尾倾角(β)、椎体前缘经椎弓根中轴线到侧块后缘的距离(SL:sagittallength);将椎体前缘等分为4个区,从椎体上缘开始分别记为1～4区,记录椎弓根轴线与椎体前缘交点所在的区域。将上述资料行统计学分析,找出下颈椎前路椎弓根螺钉的最佳进钉点及进钉方向。并据此模拟置入下颈椎前路椎弓根螺钉。结果:下颈椎水平轴位像上前路椎弓根外倾角在38°～45°,C3-C5逐渐增大,C5-C7逐渐减小;下颈椎矢状轴位像上,C3、C4前路椎弓根为头倾,C5基本水平,C6、C7为尾倾。C3-C5头倾角逐渐减小,C5-C7尾倾角逐渐增大。AL及SL从C3到C7呈现逐渐增加趋势。下颈椎椎弓根水平轴位像上,C3、C4及C5多数交点在2区内,C6在2区与3区内的数目基本相同,而C7则多数位于3区内。下颈椎椎弓根矢状轴位像上,C3、C4及C5多数交点在1区内,C6在1区与2区内的数目基本相同,而C7则多数位于2区。下颈椎椎弓根水平轴位像上交点在1区和4区的个数极少;而矢状轴位像上交点在3区及4区的个数极少。根据研究结果在临床上行3例共6枚下颈椎椎弓根螺钉的置入,均取得成功,未见并发症。结论:下颈椎椎弓根螺钉最佳进钉点C3、C4、C5多数位于中线略偏向拟置钉椎弓根的对侧、椎体的上1/4区域内;而在C7则多数位于中线略偏向拟置钉椎弓根的同侧、椎体的上2/4区域内,C6位于两者间。下颈椎椎弓根螺钉的最佳进钉方向在水平轴位上为外倾38°～45°,C3-C5逐渐增大,C5-C7逐渐减小;而在矢状轴位像上,C3、C4为头倾5°～10°,C5水平,C6、C7为尾倾5°～10°。下颈椎前路椎弓根螺钉是一项可行的前路内固定技术。     

A free‐hand technique for pedicle screw placement in the lower cervical spine

Objective: To describe a free‐hand method for pedicle screw placement in the lower cervical spine with no intraoperative imaging monitors, and to evaluate the safety of this technique. Methods: A study of the free‐hand technique of cervical pedicle screw placement was conducted by postoperative radiological review and follow‐up. Thirty‐six patients who had had cervical reconstruction with posterior plate utilizing pedicle screw fixation, and been followed for a minimum of 2 years, were studied. The position of the pedicle screw was evaluated by postoperative oblique radiographs and axial computed tomograms. Clinical outcomes were measured by Odem's criteria. Results: A total of 144 screws of diameter 3.5 or 4.0 mm were inserted into the cervical pedicles in 36 patients. Postoperative images showed that 16 (11.1%) of the screws had penetrated the pedicle walls. Among them, 10 (6.9%) screws had penetrated the lateral, 4 (2.8%) the superior and 2 (1.3%) the inferior walls. However, there were no neurological or vascular complications related to the malpositioned screws during a minimum of 2 years follow‐up. In addition, Odem's scores were applied postoperatively in all patients except one with complete neurological deficit. Conclusion: Based on 144 screw placements, cervical pedicle screw insertion utilizing a free‐hand technique without intraoperative imaging guidance seems to be safe and reliable. However, solid knowledge of the anatomy of the cervical pedicle and adjacent neurovascular bundles, and careful preoperative review of cervical images, are imperative for successful screw placement in the cervical spine.     

Radiographic evaluation of cervical spine trauma. Plain radiography and conventional tomography versus computed tomography

Different imaging modalities are available for the diagnosis of cervical spine injuries. There is a controversial discussion about whether plain radiography (PR), conventional tomography (CTO) or computed tomography (CT) should primarily be used. PR and CTO are more often available and less costly than CT. Especially in second-care hospitals, CT is not always available. The diagnostic work-up in these centres has to rely on conventional techniques. The aim of this study was to define the role of PR supplemented by CTO in the diagnosis of cervical spine trauma in comparison to CT. Twenty-five patients were identified who underwent plain radiography (PR), conventional tomography (CTO) and computed tomography (CT) for the diagnosis of a cervical fracture. In 19 patients a fracture of the cervical spine was identified. All images were reviewed by two independent observers to estimate the interobserver variability. The highest detection rate was achieved by CT (18/18 fractures detected for observer 1/2), followed by CTO (16/16 fractures) and then PR (15/14 fractures). When the detection rates of PR and CTO are combined, 18 fractures were detected by each of the observers. The results were analysed for the dens and the rest of the cervical spine independently. For PR and CTO the detection rates were lower for fractures of the dens than for the rest of the cervical spine. We conclude that the combination of PR and CTO accurately detects fractures of the cervical spine compared with CT. If a fracture of the dens is suspected, the patients should be referred to CT due to its superior accuracy in this region. Received: 25 April 2000     

Morphologic evaluation of cervical spine anatomy with computed tomography: anterior cervical plate fixation considerations

The computed tomography (CT) studies of the cervical spine from 50 males and 50 females were reviewed to provide morphometric data on a variety of anatomic parameters relevant to anterior cervical reconstruction and fixation. Measurements were made of the vertebral body width and midsagittal anteroposterior (AP) diameter and the distance between the medial borders of the longus coli muscles. Distances between adjacent endplates were also measured, both at their midpoint and at the anterior margin. Widths of the vertebral bodies measure 24.6 +/- 2.4 and 23.0 +/- 2.4 mm in males and females, respectively, with the narrowest measuring 17 and 14, respectively. The average midsagittal AP diameter of each vertebral body in males was approximately 17-18 mm, with the smallest AP diameter measured to be 13 mm. The average midsagittal AP diameter of each vertebral body in females was approximately 15-16 mm, with the smallest being 10 mm. CT scanning provides excellent osseous detail for the measurement of such parameters, and with its widespread use in the evaluation of cervical disorders, large numbers of patients can be reviewed.