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  脊柱外科杂志  2017, Vol.15 Issue(3): 167-170   PDF    
前路手术对颈椎椎间盘突出症患者颈椎矢状位参数的影响
刘蔚, 唐鹏宇, 罗勇骏, 周快, 凡进, 周炜, 殷国勇, 张宁, 蔡卫华    
南京医科大学第一附属医院骨科, 江苏 210029
摘要: 目的 探讨前路手术对颈椎椎间盘突出症患者颈椎矢状位参数的影响。 方法 2011年1月-2016年9月在本院行前路颈椎椎间盘切除融合术(ACDF)及前路颈椎椎体次全切除融合术(ACCF)治疗的颈椎椎间盘突出症患者159例,男79例,女80例;年龄(51.85±9.60)岁。在MRI上测量颈椎矢状位参数,包括C2~7 Cobb角、T1倾斜角(T1SA)、颈倾角(NTA)和胸廓入口角(TIA),采用配对t检验比较手术前后各参数的差异。根据T1SA大小分为低T1SA组(T1SA≤20°,53例)、中T1SA组(20°<T1SA≤30°,81例)和高T1SA组(T1SA >30°,25例),采用χ2检验比较不同T1SA组间各个节段退变率的差异。 结果 术后C2~7 Cobb角、T1SA和NTA的测量结果与术前相比,差异有统计学意义(P<0.05),TIA与术前相比,差异无统计学意义。159例病例中病变共累及311个节段,其中C5/C6最多,为102个;C4/C5次之,为91个。C3/C4、C4/C5、C5/C6和C6/C7退变率在不同T1SA组之间差异有统计学意义(P<0.05),随着T1SA增加,C3/C4和C4/C5退变率逐渐增加,C5/C6和C6/C7退变率逐渐降低。 结论 前路手术可能通过增加颈椎椎间盘突出症患者C2~7 Cobb角进而增加T1SA,从而更有力地维持颈椎生理曲度;随着T1SA的增加,退变节段有由下往上发展的趋势。
关键词: 颈椎     椎间盘移位     椎间盘切除术     脊柱融合术     内固定器     图像解释, 计算机辅助    
Effect of anterior cervical spine surgery on cervical sagittal parameters in patients with cervical disc herniation
LIU W ei, TANG Peng-yu, LUO Yong-jun, ZHOU Kuai, FAN Jin, ZHOU Wei, YIN Guo-yong, ZHANG Ning, CAI W ei-hua    
Department of Orthopaedics, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China
Abstract: Objective To analyze the influence of anterior cervical spine surgery on cervical sagittal parameters in patients with cervical disc herniation. Methods From January 2011 and September 2016, 159 patients with cervical disc herniation who underwent anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF) were retrospectively studied.The study included 79 males and 80 females, whose age was (51.85±9.60) years old.The cervical sagittal parameters were measured on MRI, including C2-7 Cobb's angle, T1 slope angle (T1SA), neck tilting angle (NTA) and thoracic inlet angle (TIA), and the data were analyzed by paired samples t test between pre-and post-operation.According to preoperative T1SA, the patients were divided into low T1SA group (T1SA ≤ 20°, 53 cases), normal T1SA group (20° < T1SA ≤ 30°, 81 cases) and high T1SA group (T1SA >30°, 25 cases), and the degeneration rates were analyzed by chi-square test between different T1SA groups. Results Postoperative C2-7 Cobb's angle, T1SA and NTA showed statistically significant difference (P < 0.05) compared with the preoperative data, but TIA showed no significant difference (P>0.05).Of the 159 patients, a total of 311 segments were identified as degeneration, with C5/C6 being 102, which was the most maximum and C4/C5 being 91, taking the second place.The differences in degeneration rates of C3/C3, C4/C4, C5/C6 and C6/C7 were statistically significant between the different T1SA groups (P < 0.05).With the increase of T1SA, the degeneration rate of C3/C3 and C4/C4 increased and that of C5/C6 and C6/C7 decreased gradually. Conclusion Anterior cervical spine surgery may increase the C2-7 Cobb's angle and then increase the T1SA in patients with cervical disc herniation, thereby more effectively maintaining the lordosis of the cervical spine; with the increase of T1SA, the degenerated segment has a tendency to develop from lower level to higher level.
Key words: Cervical vertebrae     Intervertebral disc displacement     Diskectomy     Spinal fusion     Internal fixators     Image in terpretation, computer-assisted    

近年来,脊柱矢状位上的平衡逐渐引起脊柱外科医生的重视。脊柱矢状位上的平衡可以使人体以最小的能量消耗来保持身体平衡和视野水平[1],而失平衡则会导致腰腿痛等一系列临床症状[2]。目前已有大量文献报道了腰骶部骨盆入射角(PI)和腰椎前凸(LL)之间的关系,表明PI在骨盆矢状位平衡中起着重要作用[1-3],但有关颈部T1倾斜角(T1SA)和胸廓入口角(TIA)在颈椎矢状位平衡中作用的报道却不常见。因此,本研究回顾性分析了159例颈椎椎间盘突出症患者的MRI资料,对其颈椎矢状位参数进行研究,以探讨颈椎前路手术对于颈椎矢状位参数的影响,并分析T1SA的变化与病变节段的关系。

1 资料与方法1.1 一般资料

2011年1月—2016年9月在本院行颈椎前路手术的患者共1 005例,经过筛选后纳入病例159例。其中男79例,女80例;年龄26~78(51.85±9.60)岁。纳入标准:① 入院诊断为颈椎椎间盘突出症;② 在本院行颈椎前路手术治疗;③ 术前、术后均在本院行颈椎MRI检查。排除标准:① 因外伤入院;② 合并脊柱肿瘤、脊柱结核或感染等全身系统疾病;③ 既往有脊柱手术史;④ 影像学提示有骨折脱位或者既往存在骨折;⑤ 影像学相关标志显示不清等。

1.2 影像学测量方法及测量指标

通过院内PACS系统的MRI资料测量影像学参数,测量由2名有5年以上工作经验的脊柱外科医师共同完成。① C2~7 Cobb角:C2下终板垂线与C7下终板垂线之间的夹角;② T1SA:T1椎体上终板与水平线之间的夹角;③ 颈倾角(NTA):胸骨上缘与T1椎体上终板中点连线与胸骨上缘垂直线的夹角;④ TIA:胸骨上缘与T1椎体上终板中点连线与经过T1椎体上终板中点垂线的夹角(图 1)。类似于骨盆矢状位参数中的PI=骨盆倾斜角(PT)+骶骨倾斜角(SS),在颈椎矢状位参数中有TIA=T1SA+NTA。

a:C2~7 Cobb角,C2下终板垂线与C7下终板垂线之间的夹角b:T1SA,T1椎体上终板与水平线之间的夹角c:NTA,胸骨上缘与T1椎体上终板中点的连线与胸骨上缘垂直线的夹角d:TIA,胸骨上缘与T1椎体上终板中点的连线与经过T1椎体上终板中点垂线的夹角 a:C2-7 Cobb's angle is defined as angle between vertical line of C2 lower endplate and vertical line of C7 lower endplate b:T1SA is defined as angle between T1 upper endplate and horizontal plane c:NTA is defined as angle between a straight line connecting upper end of sternum and center of T1 upper endplate and a vertical line going through upper end of sternum d:TIA is defined as angle between straight line connecting upper end of sternum and midpoint of T1 upper endplate and vertical line going through midpoint of T1 upper endplate 图 1 在MRI上测量颈椎矢状位参数 Figure 1 Measurement of cervical sagittal parameters in MRI
1.3 统计学处理

采用SPSS 20.0软件对数据进行统计分析。颈椎矢状位参数的测量结果以x±s表示,采用配对样本t检验比较手术前后各参数的变化;根据T1SA的大小将159例病例分为低T1SA组(T1SA≤20°,53例)、中T1SA组(20° < T1SA≤30°,81例)和高T1SA组(T1SA > 30°,25例),采用χ2检验比较不同T1SA组间各个节段的退变率是否具有差异性。以P < 0.05为差异有统计学意义。

2 结果

术后C2~7 Cobb角、T1SA与术前相比增大,NTA与术前相比减小,三者术前、术后的测量结果差异均有统计学意义(P < 0.05,表 1);而TIA术前、术后的测量结果比较差异无统计学意义(P > 0.05,表 1)。

表 1 颈椎矢状面参数 Table 1 Cervical sagittal parameter

159例病例中病变共累及311个节段,其中C5/C6最多,为102个;C4/C5次之,为91个。随着T1SA增大,C3/C4和C4/C5退变率增加,而C5/C6和C6/C7退变率下降(表 2)。不同T1SA组各节段的退变率之间差异有统计学意义(P < 0.05,表 2)。

表 2 不同T1SA组各节段颈椎椎间盘的退变率 Table 2 Degeneration rate of cervical disc in different T1SA groups
3 讨论

脊柱术后矢状位失平衡可能是术后疼痛和功能障碍的主要原因[2, 4]。在骨盆矢状位参数中,宋凯等[5]研究发现随着PT的增加,术后功能恢复变差。颈椎矢状位平衡的重要性不亚于骨盆矢状位平

[6],因此,正常颈椎矢状位平衡的重建及维持成为颈椎手术中不可忽视的问题。关于胸椎后凸角(TK)对于颈椎曲度的影响已经有大量文献报道[7-8],但始终不能很好地解释颈椎曲度的变化,因此,人们逐渐把目光转向了颈椎矢状位参数。Lee等[9]认为T1SA和TIA能够反映颈椎的矢状位平衡,同时也是反映术后颈椎曲度的重要参数。本研究测量的术前参数(表 1)与Lee等[9]测量的结果(C2~7 Cobb角9.9°±12.5°、T1SA 25.7°±6.4°、NTA 43.7°±6.1°、TIA 69.5°±8.6°)和赵文奎等[10]测量的结果(C2~7 Cobb角12.03°±7.64°、T1SA 26.33°±7.01°)存在一定差异。这一方面是由于本研究所分析的是患有颈椎椎间盘突出症的人群,与无症状正常人群存在着差异;另一方面也提示在不同人种、不同地区人群之间颈椎曲度以及颈椎矢状位参数可能存在着差异。

本研究之所以在MRI而不是X线片或者CT上测量颈椎矢状位参数,主要有以下几点原因。① X线片上站立位时由于双肩遮挡,胸骨上缘以及T1椎体辨认不清。据相关文献报道,仅有11%的X线片能够清楚地显示胸骨上缘以及T1椎体[11]。② CT的辐射大,对人体伤害较大。③ 行颈椎前路手术时采取仰卧位姿势,与行MRI检查时的姿势类似,因此,行MRI检查更接近手术时的体位。行MRI和CT检查时采取的是仰卧位,而行X线检查时采取的是直立位,这种体位和重心的改变势必会对最后的结果产生影响。根据国外相关文献报道,尽管颈椎矢状位参数的测量结果在直立位和仰卧位上存在差异,但是两者存在着显著的相关性,因此,可以用MRI来评估颈椎矢状位参数[12]。本研究发现,术后C2~7 Cobb角、T1SA明显变大,NTA明显减小,TIA几乎不变。以往研究显示,TIA是一个固定的形态学参数,不受体位或者屈伸活动的影响[13];Lee等[9]认为T1SA受到年龄和体位姿势的影响而变化;杨洋等[14]研究也证实颈椎前路手术能够增大C2~7 Cobb角和T1SA。因此推断,个体的TIA值是恒定不变的,手术并不改变其大小。颈椎前路手术通过增大C2~7 Cobb角,继而引起T1SA增加、NTA减小。

T1SA作为颈与胸的“桥梁”,在对颈椎的研究中不可忽视。相关研究认为,低T1SA会加速颈椎退变,因而低T1SA是颈椎病的危险因素[15]。臧法智等[16]提出,在颈椎后路单开门椎板成形术中,较大T1SA可能导致颈椎曲度丢失的风险增加。本研究发现,随着T1SA增加,C3/C4和C4/C5退变率逐渐增加,C5/C6和C6/C7退变率逐渐减少。可以推测随着T1SA增大,病变节段有向上发展的趋势。其可能的机制为T1SA越小,相应C2~7 Cobb角越小,颈椎越“直”,导致应力集中,所有的负荷都集中在C6/C7上,因而C6/C7发生退变的概率就大;而随着T1SA增大,C2~7 Cobb角越大,颈椎越“弯”,负荷被逐渐分担至上位椎间盘,因而C5/C6和C6/C7退变的概率减小。目前对于此趋势的研究很少,还需要进一步研究来证实。

总之,本研究发现颈椎前路手术可能通过增加C2~7 Cobb角进而增加T1SA,从而更有力地维持颈椎生理曲度;随着T1SA的增加,退变节段有由下往上发展的趋势。本研究的不足之处在于研究对象主要为患有颈椎椎间盘突出症的病例,没有选择正常人群作为对照组进行研究;没有就颈椎退行性变病例术前、术后的临床症状改善情况展开分析;样本量偏少,数据绘测统计不可避免存在偏倚。关于颈椎前路手术对于颈椎矢状位参数的影响还需要进一步研究来证实。

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