Fractures of the cervical spine

OBJECTIVES:

The aim of this study was to review the literature on cervical spine fractures.

METHODS:

The literature on the diagnosis, classification, and treatment of lower and upper cervical fractures and dislocations was reviewed.

RESULTS:

Fractures of the cervical spine may be present in polytraumatized patients and should be suspected in patients complaining of neck pain. These fractures are more common in men approximately 30 years of age and are most often caused by automobile accidents. The cervical spine is divided into the upper cervical spine (occiput-C2) and the lower cervical spine (C3-C7), according to anatomical differences. Fractures in the upper cervical spine include fractures of the occipital condyle and the atlas, atlanto-axial dislocations, fractures of the odontoid process, and hangman''s fractures in the C2 segment. These fractures are characterized based on specific classifications. In the lower cervical spine, fractures follow the same pattern as in other segments of the spine; currently, the most widely used classification is the SLIC (Subaxial Injury Classification), which predicts the prognosis of an injury based on morphology, the integrity of the disc-ligamentous complex, and the patient''s neurological status. It is important to correctly classify the fracture to ensure appropriate treatment. Nerve or spinal cord injuries, pseudarthrosis or malunion, and postoperative infection are the main complications of cervical spine fractures.

CONCLUSIONS:

Fractures of the cervical spine are potentially serious and devastating if not properly treated. Achieving the correct diagnosis and classification of a lesion is the first step toward identifying the most appropriate treatment, which can be either surgical or conservative.     

The relationship between disc degeneration and morphologic changes in the intervertebral foramen of the cervical spine: a cadaveric MRI and CT study

A cadaveric study was performed to investigate the relationship between disc degeneration and morphological changes in the intervertebral foramen of cervical spine, including the effect on the nerve root. Seven fresh frozen human cadavers were dissected from C1 to T1, preserving the ligaments, capsules, intervertebral disc and the neural structures. The specimens were scanned with MRI and then scanned through CT scan in the upright position. Direct mid-sagittal and 45 degree oblique images were obtained to measure the dimension of the intervertebral disc height, foraminal height, width, area and segmental angles. Disc degeneration was inversely correlated with disc height. There was a significant correlation between disc degeneration and foraminal width (p<0.005) and foraminal area (p< 0.05), but not with foraminal height. Disc height was correlated with foraminal width but not with height. The segmental angles were decreased more in advanced degenerated discs. There was a correlation between nerve root compression and decreased foraminal width and area (p<0.005). This information and critical dimensions of the intervertebral foramen for nerve root compression should help in the diagnosis of foraminal stenosis of the cervical spine in patients presenting with cervical spondylosis and radiculopathy.     

生物力学评价颈椎前路椎弓根螺钉植入骨质疏松椎骨内的稳定性

背景：前路颈椎间盘切除植骨融合是治疗颈椎病的有效术式,该术式能够提供坚强固定且植骨融合率相对较高。但是,对于2个节段以上同时受累的颈椎,由于植骨跨度较大,内固定和植骨块稳定性较差,容易产生植骨融合失败、假关节形成等并发症,影响疗效。 目的：观察颈椎前路椎弓根螺钉植入骨质疏松椎骨内的生物力学稳定性。 方法：纳入12具人颈椎骨,包括6具骨密度正常颈椎骨和6具骨质疏松颈椎骨,共60个椎骨标本资料进行分析,将30个骨质疏松椎骨标本植入颈椎前路椎弓根螺钉设为颈椎前路椎弓根螺钉组,将30个骨密度正常椎骨标本植入前路椎体螺钉设为前路椎体螺钉组。从上述两组中根据骨密度值抽取40个椎骨,分别设置为即时正常骨密度组、即时骨密度疏松组、疲劳正常骨密度组以及疲劳骨质疏松组,每组10个椎骨。采用双能X射线骨密度仪测定各椎体骨密度值,采用ElectroForce 3510材料试验机对两种螺钉进行生物力学指标测试。 结果与结论：颈椎前路椎弓根螺钉组骨矿盐含量、椎体螺钉拔出力、椎体螺钉拔出刚度、椎弓根螺钉拔出力、椎弓根螺钉拔出刚度均显著高于前路椎体螺钉组(P < 0.05)。颈椎前路椎弓根螺钉即时正常骨密度标本最大轴向拔出力、即时骨质疏松标本最大轴向拔出力、疲劳正常骨密度标本最大轴向拔出力、疲劳骨质疏松标本最大轴向拔出力均显著高于高于前路椎体螺钉(P < 0.05)。结果证实,与颈椎前路椎体螺钉相比,颈椎前路椎弓根螺钉在骨质疏松椎骨内生物力学性能更加稳定。中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

椎间融合器高度对颈椎生物力学影响

目的研究颈椎前路减压融合术中椎间融合器高度对颈椎生物力学影响,为融合器选择提供参考。方法建立正常颈椎C2~7节段有限元模型并验证,在C5~6节段分别植入高度为5、6、7、8 mm的融合器,施加1.5 N·m力矩使颈椎产生前屈、后伸、侧弯和轴向旋转运动,并探究融合器高度变化对颈椎活动度(range of motion,ROM)、小关节应力、椎间压强等的影响。结果融合器高度每增加1 mm,手术节段的角度值平均增加0.68°。植入融合器后C5~6 ROM范围小于0.44°。融合器高度差异对C4~5的ROM影响大于C6~7,对非融合节段ROM的影响小于7.3%。融合器高度差异对非手术节段ROM、小关节应力、相邻节段椎间压强的影响较小。关节囊韧带、融合器和钉板系统应力均随融合器高度增加而明显增加,6、7、8 mm融合器模型的关节囊韧带、融合器和钉板系统应力均远高于5 mm融合器模型。结论对于需要植入融合器的患者,建议植入物高度比原椎间隙高0~1 mm。     

临床症状不同颈椎病患者颈椎间盘白细胞介素1β及白细胞介素6和环氧化酶2的表达

BACKGROUND: During degeneration of cervical spine, biochemical changes appeared in intervertebral disc cells. During this process, a variety of inflammatory cytokines may lead to disc herniation, which stimulates the production of a variety of inflammatory factors from surrounding adjacent tissue.     

颈椎间盘突出程度与颈椎X线片相关指标测量值的相关性研究

目的探讨单节段脊髓型颈椎病患者颈椎X线片相关指标与椎间盘突出导致的颈脊髓压迫严重程度的相关性。方法回顾性分析2012年8月—2014年3月安徽医科大学第一附属医院脊柱外科诊治的60例单节段脊髓型颈椎病患者的临床资料,均为男性,年龄42~65岁,平均(54.8依9.3)岁。在颈椎MRI矢状位成像上按照颈脊髓受压的比例( E值)分为Ⅰ组、Ⅱ组及Ⅲ组。在颈椎MRI横断面成像上测量并计算颈髓横切面积( S1)与有效椎管横切面积( S0)的比值,以此判断椎间盘突出程度;在不同体位颈椎X线摄片上测量责任椎间隙的活动度值(B值)、椎间隙前缘高度( D值)、颈椎C2~7 Cobb角及椎间孔面积( M值)等相关指标。采用直线相关回归分析颈椎间盘突出程度与各观测指标之间的相关性。结果3组间S1/S0值、E值、B值、D值、C2~7 Cobb角和M值差异均有统计学意义(F值分别为44.187、112.789、7.232、3.778、3.232、15.813,P值均<0.05)。随着S1/S0值的增加,E值、B值、D值、C2~7 Cobb角和M值均逐渐减小,提示责任椎间隙E值、B值、D值、C2~7 Cobb角、M 值与 S1/S0值均呈负相关性( R 值分别为-0.821、-0.581、-0.378、-0.419、-0.576,P值均<0.05)。经多元线性回归分析,B 值、D 值、M 值是 S1/S0的3个独立影响因素, S1/S0值的预测方程为^Y=118.955-1.348X1-2.850X2-0.541X3(复相关系数R=0.742,决定系数R2=0.550,F=22.841,P<0.01),回归模型有统计学意义。结论不同体位颈椎X线摄片的相关指标B值、D值、M值是影响脊髓型颈椎病椎间盘退变突出程度的独立因素,对评估单节段脊髓型颈椎间盘突出的严重程度有一定的诊断价值;采用D值、B值及M值为3个自变量指标,可对椎间盘突出进行预测。     

腰椎间盘结构、盘内压力及不同载荷的影响：生物力学研究进展

背景：腰椎间盘突出是临床引起腰腿疼的最主要原因,严重影响患者的日常生活、学习与工作,而对腰椎间盘的生物力学特点进行研究,对预防和治疗腰椎间盘疾病具有重要指导意义。 目的：综述目前腰椎间盘生物力学的研究进展。 方法：由第一作者用中国期刊全文数据库和PubMed数据库,检索时间：2009至2014年,检索词分别为“椎间盘、髓核、生物力学、纤维环、软骨板” 和“intervertebral disc,nucleus pulposus,biomechanics,fibrosis annulus,cartilage”,语言分别设定为中文和英文。纳入与腰椎间盘、髓核、纤维环及软骨板的生物力学特性相关的研究,排除重复及陈旧文献。共检索到5 072篇文章,按纳入和排除标准对文献进行筛选,共纳入49篇文章进行综述分析。 结果与结论：通过对腰椎间盘结构特点、不同载荷的影响、腰椎间盘内压力、腰椎间盘退行性改变的生物力学特点以及腰椎间盘力学模型的建立等方面进行综述,有助于充分了解腰椎间盘相关问题的发生机制、发展过程以及造成的不良后果。对于腰椎间盘的日常保健及如何能更好的运用“力”这个物理因子解决腰椎间盘问题具有指导意义。     

人工颈椎间盘置换术后颈椎活动与稳定性的评价

目的:评价人工颈椎间盘置换术对颈椎活动与维持手术节段稳定性的作用及临床效果。方法:18例非手术治疗无效的颈椎病(脊髓型、神经根型或/和混合型)行前路颈椎间盘切除后置入Bryan人工颈椎间盘,按计划进行定期随访(6～20个月,平均14个月),根据手术前后颈椎的动力位X线片分析手术节段的稳定性。并结合病人神经症状和体征的改善情况评价其临床效果。结果:手术效果优9例,良5例,一般3例,差1例。手术前平均JOA评分为12分,术后平均为15.5分;手术节段前屈后伸术前运动范围12.8°±5.7°,术后11.2°±5.4°;邻近间隙术前屈伸运动范围11.9°±5.8°,术后11.4°±4.9°。术前后比较无统计学差异(P>0.05)。未发现假体松动和移位。结论:人工颈椎间盘置换术安全可靠,病人恢复快,既可保持手术节段颈椎稳定,又可维持颈椎的生理活动度。     

椎弓根螺钉及颈椎体螺钉置入内固定后的生物力学及稳定性比较

BACKGROUND: From the point of view of human anatomy, the load of the spine is more. When the body moves, the range of activities, and activity are relatively large. After screws were implanted in the spine, if biomechanical properties and stability are not up to the standard, it easily leads to lack of grip force of screw and screw loosening so as to increase the incidence of complications after treatment.      

人工颈椎间盘置换与前路颈椎间盘切除融合后邻近节段椎间盘应力分布的有限元对比

BACKGROUND: Previous clinical follow-up study showed that disc degeneration of adjacent segment after anterior cervical discectomy and fusion was faster than that of artificial cervical disc replacement. Compared with the anterior cervical discectomy and fusion, artificial cervical disc replacement can maintain a good range of motion of replacement segment. Further investigation should be taken to compare the difference between stress and fusion after replacement.      

Effects of degenerated intervertebral discs on intersegmental rotations,intradiscal pressures,and facet joint forces of the whole lumbar spine

The effects of intervertebral disc (IVD) degeneration on biomechanics of the lumbar spine were analyzed. Finite element models of the lumbar spine with various degrees of IVD degeneration at the L4-L5 functional spinal unit (FSU) were developed and validated. With progression of degeneration, intersegmental rotation at the degenerated FSU decreased in flexion–extension and left–right lateral bending, intradiscal pressure at the adjacent FSUs increased in flexion and lateral bending, and facet joint forces at the degenerated FSU increased in lateral bending and axial rotation. These results could provide fundamental information for understanding the mechanism of injuries caused by IVD degeneration.     

Effects of freezing on the biomechanics of the intervertebral disc

Summary Storage of anatomic specimens is possible only if there is a reliable method for preservation of the tissues. The establishment of such a procedure is thus of twofold importance: clinical (transplantation of segments of the vertebral column) and experimental (research and teaching programs). Simple freezing at –18° C is the simplest and least expensive method for storing spinal specimens compared to other modes of storage such as cryo-preservation and lyophilization. Does this mode of storage affect the biomechanics of frozen anatomic specimens, in particular those of the intervertebral disc? This experiment dealt with the comparative biomechanical analysis before and after three months of freezing of 19 segments of the sheep vertebral column (4 functional C4–C5 units, 3 C7-T1 units, 6 T13-L1 units and 6 L5–L67 units). The results showed that there was no significant difference (risk of error 5%) between frozen and fresh segments of vertebral column in terms of amplitude and rigidity, except for the C7-T12 segment where the conditions of validity of the statistical tests were not met. The results of this experiment allowed us to validate a biomechanical model to assay the effects of freezing.

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Effets de la congélation sur la biomécanique du disque intervertébral

Résumé Le stockage des pièces anatomiques n'est possible que s'il existe un mode de conservation fiable des tissus biologiques. La détermination d'un tel procédé présente donc un double intérêt clinique (transplantation de segments de colonne vertébrale) et expérimental (programme d'enseignement et de recherche). La congélation simple à –18° C est, parmi les autres modes de conservation tels que la cryopréservation et la lyophilisation, le moyen le plus simple et le moins coûteux de conserver des pièces rachidiennes. Ce mode de conservation altère t-il la biomécanique de pièces anatomiques congelées et tout particulièrement celle du disque intervertébral ? Cette expérimentation a porté sur l'analyse biomécanique comparée avant et après trois mois de congélation de 19 segments de colonne vertébrale de mouton (4 unités fonctionnelles C4–C5, 3 unités C7-T1, 6 unités T13-L1 et 6 unités L5–L6). Les résultats montrent qu'il n'existe pas de différence significative (avec un risque d'erreur de 5 %) entre les segments de colonne vertébrale congelés et frais en terme d'amplitude et de rigidité à l'exception du segment C7-T1 où les conditions de validité des tests statistiques ne sont pas réunies. Les résultats de cette expérimentation permettent de valider ainsi un modèle biomécanique congelé.

     

Effects of freezing on the biomechanics of the intervertebral disc

Storage of anatomic specimens is possible only if there is a reliable method for preservation of the tissues. The establishment of such a procedure is thus of twofold importance: clinical (transplantation of segments of the vertebral column) and experimental (research and teaching programs). Simple freezing at ?18°C is the simplest and least expensive method for storing spinal specimens compared to other modes of storage such as cryo-preservation and lyophilization. Does this mode of storage affect the biomechanics of frozen anatomic specimens, in particular those of the intervertebral disc? This experiment dealt with the comparative biomechanical analysis before and after three months of freezing of 19 segments of the sheep vertebral column (4 functional C4-C5 units, 3 C7-T1 units, 6 T13-L1 units and 6 L5-L67 units). The results showed that there was no significant difference (risk of error 5%) between frozen and fresh segments of vertebral column in terms of amplitude and rigidity, except for the C7-T12 segment where the conditions of validity of the statistical tests were not met. The results of this experiment allowed us to validate a biomechanical model to assay the effects of freezing.     

加压与不加压固定融合器对腰椎融合的影响

BACKGROUND: The posterior lumbar interbody fusion is one of the effective methods for the treatment of lumbar and sacral spine diseases. Most surgeons fix the cage by compressing the disc space in order to keep stability and prevent dislodgement. However, some surgeons think that the non-compression technique does favor for increasing of the disc and foraminal height and thus improving the clinical outcomes, and does not increase the risk of fusion shift.     

Finite element analysis of the spine: towards a framework of verification, validation and sensitivity analysis

A number of papers have recently emphasised the importance of verification, validation and sensitivity testing in computational studies within the field of biomechanical engineering. This review examines the methods used in the development of spinal finite element models with a view to a standardised framework of verification, validation and sensitivity analysis. The scope of this paper is restricted to models of the vertebra, the intervertebral disc and short spinal segments. In the case of single vertebral models, specimen-specific methods have been developed, which allow direct validation against experimental tests. The focus of intervertebral disc modelling has been on representing the complex material properties and further sensitivity testing is required to fully understand the relative roles of these input parameters. In order to construct complex multi-component short segment models, many geometric and material parameters are required, some of which are yet to be fully characterised. There are also major challenges in terms of short segment model validation. Throughout the review, areas of good practise are highlighted and recommendations for future development are proposed, taking a step towards more robust spinal modelling procedures, promoting acceptance from the wider biomechanics community.     

Hybrid手术对颈椎力传导方式的影响

目的研究人工椎间盘置换(total disc replacement,TDR)合并融合的Hybrid手术后颈椎的力传导模式,从生物力学角度加深对Hybrid手术的认识。方法建立正常颈椎有限元模型(INTACT模型),模拟C4~6节段退变的3种手术方案:上置换+下融合(TDR45模型)、上融合+下置换(TDR56模型)、双节段融合(Fusion456模型)。结果所有手术模型中,融合节段的活动能力完全丧失,置换节段的活动能力有所增加。在160 N轴向力作用下,INTACT模型整个节段后伸4°,而TDR45与TDR56模型的颈椎节段分别后伸8.2°与8.9°。在TDR56模型中,经过C5椎体的力减少20%,经过置换节段小关节的力增加3.8倍。在TDR45模型中,经过置换节段小关节的力增加50%。INTACT模型的最大关节应力为0.8 MPa,而TDR45与TDR56模型置换节段的小关节应力均高达正常颈椎的2倍。结论由于置换节段活动范围的增加,Hybrid术后颈椎曲度在轴向力作用下发生较大改变(后伸)。这种改变将导致经过置换节段椎体的力有所减少,而经过小关节的力有所增加,从而增加置换节段小关节的应力。     

椎板侧方入路治疗极外侧腰椎间盘突出症的应用解剖

目的:为后正中经椎板侧方入路手术治疗极外侧腰椎间盘突出症提供显微外科解部学基础。方法:20具经防腐固定的成人尸体标本,观测横突间韧带厚度、前后方血管和腰神经前支走行。结果:横突间韧带厚度0.60～1.39mm;L3～5节段动脉前支及伴行静脉90%以上位于相邻横突间韧带腹侧上1/2处,横突间韧带背侧中1/3处有一恒定节段动脉分支;腰神经前支与矢状面夹角18.9°～39.2°,下位横突的副突处距前方走行腰神经前支距离为5.63～8.05mm,椎弓峡部侧缘至腰神经前支的距离为1.73～3.64mm。结论:横突间韧带是该入路重要的解剖学标志,熟悉其应用解剖对手术治疗极侧腰椎间盘突出症具有重大指导意义。     

尼古丁在人椎间盘髓核细胞退变中的作用

目的探讨不同浓度及时间的尼古丁在人椎间盘髓核细胞退变中的作用。方法随机选择5例腰椎骨折患者的椎间盘髓核组织进行体外细胞培养,种于12孔板中,按照0、1、33.3、100、200、500ng/m L的尼古丁浓度以及1、2、3、7、10天加入来培养,每组细胞用Trizol法提取总RNA,用荧光定量PCR测定AQP1,AQP3和II型胶原(Collagen)以及蛋白多糖(Aggrecan)的m RNA表达。用SPSS19.0进行统计分析。结果随着尼古丁浓度升高及培养时间的延长,髓核细胞形态变化明显,贴壁能力减弱,胞质减少,胞核萎缩,空泡形成,凋亡增加。且细胞AQP1及AQP3的m RNA水平随着尼古丁浓度及时间的增加而降低,II型胶原及蛋白聚糖m RNA水平也降低,细胞发生退变。结论尼古丁会降低人椎间盘髓核细胞AQP1和AQP3的表达,进而降低髓核细胞II型胶原和蛋白聚糖的表达,促进椎间盘退变,且作用时间越长,浓度越高,细胞退变越严重。     

Demonstration of the appearance of the paraspinal musculoligamentous structures of the cervical spine using ultrasound

The application of ultrasound in the imaging of the neck has primarily focussed on anterior structures (e.g., thyroid gland). Structures located on the posterior aspect of the neck have received little attention. This study illustrates the capability of modern ultrasound equipment in visualising the musculoligamentous structures of the neck, particularly the paraspinal musculature. Ten healthy adult volunteers (6 female; 4 male) underwent ultrasound examination of the cervical spine. A standardised technique for transducer placement was adopted and successive images of the neck of each subject were obtained. Spatial compound (extended field of view) images were obtained in subjects using one of two different ultrasound systems. Images of structures produced by ultrasound were compared to those achieved with magnetic resonance imaging in three subjects. Identification of key landmarks aided orientation and identification of structures. The internal architecture of the musculoligamentous structures of the cervical spine, especially the posterior neck muscles, was demonstrated well using ultrasound. Our study showed that modern ultrasound equipment is capable of producing clear images of the posterior cervical spine musculature and certain bony features.