影响单纯枢椎环骨折稳定性的各解剖结构骨折三维CT分型研究及临床意义

Study and clinical significance of three-dimensional CT classification of fractures with different anatomical structures affecting the stability of single axial ring fractures

中文关键词:  枢椎环骨折  稳定性  CT三维重建  MRI

英文关键词:Axis ring fracture  Stability  Three-dimensional reconstruction of CT  MRI

中文摘要:

  【摘要】 目的：采用X线片、CT扫描+三维重建及MRI图像观察单纯枢椎环骨折影像学特征，根据各解剖结构骨折的特点及对稳定性的影响进行三维CT分型，探讨其临床意义。方法：在多中心保存的病例库中查找2008年1月～2018年12月间所有Hangman骨折患者临床和影像资料，查找单纯枢椎环骨折患者（指在X线片上诊断为Levine-Edwards分型Ⅰ型Hangman骨折，再通过MRI影像排除C2/3椎间盘韧带复合体损伤信号）。将枢椎环各解剖结构骨折观察对象分为双侧上关节突（superior articular process，SAP）、双侧下关节突（inferior articular process，IAP）和双侧椎板骨折（cervical vertebral lamina，CL），双侧椎弓根骨折、双侧椎体后壁骨折。将枢椎环骨折分为前环（双侧上关节突、双侧椎体后壁）、中环（双侧椎弓根）和后环（双侧下关节突、双侧椎板）骨折，计数比较前、中、后环骨折发生率。根据枢椎环的损伤特点结合以往学者对不典型Hangman骨折的分型，将单纯枢椎环骨折分为A、B、C三型（A型，骨折以椎弓根为轴心，包括双侧C2椎弓根对称性或非对称性骨折，一侧椎弓根骨折合并对侧关节突、椎板骨折；B型，骨折以一侧椎体后壁为轴心合并对侧椎弓根，对侧关节突、对侧椎板骨折；C型，骨折以双侧椎体后壁为轴心，枢椎体边缘骨折，枢椎环不完整，包括双侧椎体后壁对称性或非对称性骨折）。观察单纯枢椎环骨折中各解剖结构骨折的特点和发生率，探讨C2/3椎间隙无移位成角和前后纵韧带损伤的条件下单纯枢椎环骨折的发生规律和稳定性。结果：共收集单纯枢椎环骨折52例，男性34例，女性18例；年龄22~83岁，平均47.9±15.7岁。合并椎间关节（上关节突和下关节突）骨折36例共50处骨折占69.2%（36/52），单纯骨性损伤16例30处骨折占30.8%（16/52）。前、中、后环骨折共发生149处，前环骨折92处占61.7%，中环骨折28处占18.8%，后环骨折29处占19.5%。在单纯枢椎环骨折中B型发生率最高，C型发生率次之，A型发生率最低。三组之间发生率多重比较有统计学差异（P<0.05）：A型骨折中椎间关节、椎板骨折发生率较B、C两型更低，B、C两型之间椎间关节、椎板骨折发生率无统计学差异（P＞0.05）。结论：单纯枢椎环骨折中椎间关节骨折发生率较高，其过伸压缩应力大多作用于前环、中环，旋转应力作用于后环。单纯枢椎环骨折是一个刚性闭合骨环的骨折，若出现双处骨折，为不稳定骨折；出现双侧上关节突、双侧下关节突、双侧椎板等解剖结构骨折时更加不稳定。采用本文新分型对该类骨折稳定性的判断更准确。

英文摘要:

  【Abstract】 Objectives: To observe the imaging features of single axial ring fractures using X-ray, CT scan and MRI, three dimensional CT classification was conducted according to the characteristics of each anatomical structure fracture and its influence on stability, to explore its clinical significance. Methods: The clinical and imaging data of all patients with Hangman fracture from January 2008 to December 2018 were searched in the multi center prospective case database, and the patients with simple axis ring fracture were found(referring to Levine-Edwards type I Hangman fracture diagnosed on X-ray films, and C2/3 abnormal signal of injury of ligament complex of intervertebral disc was excluded by MRI images). The fracture of each anatomical structure of the axis ring was divided into bilateral superior articular process(SAP), bilateral inferior articular process(IAP) bilateral lamina fracture(CL), bilateral pedicle and posterior wall fractures. The fracture of axis ring was divided into anterior ring(bilateral superior articular process, bilateral posterior wall of vertebral body), middle ring(bilateral pedicle) and posterior ring(bilateral inferior articular process, bilateral lamina). The incidence of anterior, middle and posterior ring fracture was compared. According to the injury characteristics of the axial ring and the classification of the atypical Hangman fracture by the previous scholars, the simple axial ring fracture was divided into three types: A, B and C(Type A, with pedicle as the center, including bilateral C2 pedicle symmetrical or asymmetric fractures; one side pedicle fracture with opposite articular process and lamina fractures. Type B, the fracture was centered on the posterior wall of one side of the vertebral body and combined with the fracture of the contralateral pedicle, contralateral articular process and contralateral lamina. Type C, the fracture was centered on the posterior wall of both sides of the vertebral body, with the edge fracture of the axial vertebral body and the incomplete axis ring, including the symmetrical or asymmetrical fracture of the posterior wall of both sides of the vertebral body). To observe the characteristics and the incidence of the fracture of each anatomical structure in the simple axis ring fracture, and to explore the regularity and stability of the simple axis ring fracture under the condition of C2/3 intervertebral space without displacement and angulation and anterior and posterior longitudinal ligament injury. Results: According to the inclusion and exclusion criteria, data of 52 cases(34 males and 18 females) of simple fracture of the axis ring were collected. The average age was 47.9±15.7 years, ranging from 22 to 83 years old. In this group, there were 36 cases(69.2%) with 50 fractures of intervertebral joints(SAP and IAP) and 16 cases(30.8%) with 30 fractures of simple bone injury. There were 149 ring fractures: 92 anterior ring fractures(61.7%), 28 middle ring fractures(18.8%) and 29 posterior ring fractures(19.5%). The incidence of type B was the highest, type C was the second, and type A was the lowest. There was statistical difference in the incidence of complications among the three groups(P<0.05). The incidence of type A complicated with peripheral anatomical fractures was lower than that of type B and C, and there was no statistical difference between type B and C(P＞0.05). Conclusions: In the simple axis ring fracture, the incidence of the intervertebral jointfractureis high. The hyperextension compression stress mostly acts on the anterior ring and the middle ring, while the rotation stress acts on the posterior ring. Simple axis ring is a rigid closed bone ring, if there are two anatomical fracture, it is unstable; it is more unstable when there are bilateral upper articular process, bilateral lower articular process, bilateral lamina fractures. The new classification in this paper is more accurate to judge the stability of this kind of fracture.