脊柱外科杂志  2024, Vol.22 Issue(4): 251-256   PDF    
颈椎后路单开门术中微型钛板联合侧块螺钉内固定的影像学测量及可行性分析
周龙彪1,2, 王宏1, 王爽1, 郑亮1, 张翼楠1,2, 朱贺1,2, 于海龙1, 陈语1     
1. 北部战区总医院骨科, 沈阳 110016;
2. 锦州医科大学北部战区总医院研究生培养基地, 沈阳 110016
摘要: 目的 基于影像归档和通信系统(PACS)测量颈椎侧块相关影像学参数,比较微型钛板与侧块螺钉位置关系对微型钛板联合侧块螺钉内固定术中置钉成功率的影响。方法 收集2021年9月—2021年12月在北部战区总医院骨科门诊行颈椎CT检查的116例患者的颈椎CT数据,并传输至PACS,测量C3~7侧块后表面长度(PSL)和下极角(LPA)。模拟微型钛板联合4种侧块螺钉置钉技术(Roy-Camille、Magerl、Riew和Cheng技术),在不破坏关节突的前提下计算所需最小PSL,若计算值小于实际PSL则定义为置钉成功,反之为置钉失败。根据微型钛板与侧块螺钉位置关系分为上组(微型钛板位于侧块螺钉上方)和下组(微型钛板位于侧块螺钉下方),并比较置钉成功率的组间差异。计算不同置钉技术中置钉成功率较高组所需最小PSL。结果 Magerl上组置钉成功率为17.4%,下组置钉成功率为0.2%;Camille上组置钉成功率为60.5%,下组置钉成功率为0.2%;Riew上组置钉成功率为69.3%,下组置钉成功率为0;Cheng上组置钉成功率为85.2%,下组置钉成功率为0;上组整体置钉成功率为58.1%,下组整体置钉成功率为0.1%;不同置钉技术上组置钉成功率均高于下组,差异具有统计学意义(P < 0.05)。Magerl上组所需最小PSL为15.6 mm、Camille上组为13.1 mm、Riew上组为12.5 mm、Cheng上组为11.5 mm。结论 在微型钛板联合侧块螺钉置钉技术中,微型钛板放置于侧块螺钉上方时置钉成功率较高。其中,Riew上组和Cheng上组有更高的置钉成功率,为颈椎后路单开门微型钛板联合侧块螺钉内固定术安全、可行的策略。若颈椎侧块PSL < 11.5 mm,则不建议行联合手术。
关键词: 颈椎    内固定器    放射摄影影像解释,计算机辅助    
Imaging measurement and feasibility analysis of micro-titanium plate combined with lateral mass screw internal fixation in posterior cervical single-door surgery
Zhou Longbiao1,2, Wang Hong1, Wang Shuang1, Zheng Liang1, Zhang Yinan1,2, Zhu He1,2, Yu Hailong1, Chen Yu1     
1. Department of Orthopaedics, General Hospital of Northern Theater Command, Shenyang 110016, Liaoning, China;
2. Postgraduate Training Base, General Hospital of Northern Theater Command, Jinzhou Medical University, Shenyang 110016, Liaoning, China
Abstract: Objective To measure the imaging parameters related to cervical lateral mass using the picture archiving and communication system(PACS), and compare the effect of the position relationship between micro-titanium plates and lateral mass screws on the success rate of screw placement in micro-titanium plate combined with lateral mass screw internal fixation surgery. Methods From September 2021 to December 2021, the cervical CT data of 116 patients who underwent cervical CT examination at the orthopedic outpatient department of the General Hospital of Northern Theater Command were collected and transmitted to PACS. The posterior surface length(PSL) and lower pole angle(LPA) of the C3~7 lateral masses were measured. The micro-titanium plate combined with 4 types of lateral mass screw placement techniques(Roy-Camille, Magerl, Riew and Cheng techniques) were simulated, and the minimum required PSL without damaging the articular process was calculated. If the calculated value was less than the actual PSL, it was defined as successful screw placement; otherwise, it was defined as failed screw placement. According to the position relationship between the micro-titanium plate and the lateral mass screw, the patients were divided into upper group(the micro-titanium plate was located above the lateral mass screw) and lower group(the micro-titanium plate was located below the lateral mass screw), and the differences in the success rate of screw placement between the groups were compared. The minimum required PSL for the groups with higher success rates of screw placement in the different screw placement techniques was calculated. Results The success rate of screw placement was 17.4% in the Magerl upper group and 0.2% in the Magerl lower group. The success rate of screw placement was 60.5% in the Camille upper group and 0.2% in the Camille lower group. The success rate of screw placement was 69.3% in the Riew upper group and 0 in the Riew lower group. The success rate of screw placement was 85.2% in the Cheng upper group and 0 in the Cheng lower group. The overall success rate of screw placement of upper groups was 58.1%, and the overall success rate of screw placement of lover group was 0.1%. Overall, the success rate of screw placement in the upper group was higher than that in the lower group in different screw placement techniques, and the difference was statistically significant(P < 0.05). The minimum required PSL for Magerl upper group was 15.6 mm, Camille upper group 13.1 mm, Riew technical upper group 12.5 mm, and Cheng upper group 11.5 mm. Conclusions Among the micro-titanium plates combined with lateral mass screw placement techniques, the success rate of screw placement was higher when the micro-titanium plate was placed over the lateral mass screws. Among them, the Riew upper group and the Cheng upper group both have a higher success rate of screw placement, which suggest that the micro-titanium plate located above the lateral mass is a feasible and relatively safe strategy in posterior cervical single-door plate-screw internal fixation. However, it is not recommended to perform combined surgery if the PSL of the cervical lateral mass less than 11.5 mm.
Key words: Cervical vertebrae    Internal fixators    Radiographic image interpretation, computer assisted    

近年来,一些脊柱外科医师尝试将椎板成形术与融合术联合应用,以保留椎板,防止脊髓过度后移,减少神经根牵拉,保持良好的颈椎曲度。对于合并颈椎不稳的患者,联合手术可以保持颈椎稳定性,并为门轴侧提供更大面积植骨床,提高融合率[1]。经典的联合术式是缝线悬吊联合侧块螺钉内固定术,但缝线悬吊法存在门轴侧骨折、难以控制椎管扩大角度及再关门等问题[2-4]。为了克服这些问题,有研究者[5]尝试在联合手术中采用微型钛板联合侧块螺钉内固定,可进行单侧或双侧内固定,双侧侧块螺钉内固定可使颈椎保持在更稳定的位置;同时,在临床应用中也发现,微型钛板与侧块螺钉联合使用时开门侧存在螺钉侵犯关节突、微型钛板和侧块螺钉放置困难等问题。有研究[6]表明,微型钛板与侧块螺钉不同位置关系可能对上述问题产生影响。本研究测量侧块相关影像学参数,比较了微型钛板与侧块螺钉位置关系对置钉成功率的影响,并比较了不同置钉方式的成功率,同时计算出联合手术所需的最小侧块后表面长度(PSL),为临床手术提供参考。

1 资料与方法 1.1 一般资料

回顾性分析2021年9月—2021年12月就诊于北部战区总医院骨科门诊的患者资料,对存在颈痛伴四肢感觉、运动障碍的患者进行分析,将其中行CT检查诊断为多节段脊髓型颈椎病的患者纳入研究,共收集124例颈椎CT数据并传输至影像归档和通信系统(PACS)[7]。纳入标准: ①年龄 > 18岁;②影像学资料完整。排除标准: ①颈椎外伤史及手术史;②颈椎肿瘤、结核、强直性脊柱炎等其他疾病;③颈椎椎体或侧块解剖变异;④颈椎侧块退行性变严重自发融合。根据上述标准,最终纳入患者116例,其中男84例、女32例,年龄为(62.1±11.6)岁。

1.2 影像学测量

调节PACS主操作窗口(图 1),将子窗口中的绿线、红线、紫线分别标记为XYZ轴。通过调节子窗口c、d中的Y轴,使之平行于目标椎体上终板。接着通过调节子窗口a中的X轴,使其平行于目标椎体双侧上关节突边缘连线,上下调节找到通过椎弓根平面侧块的横断面图像。然后在d窗口中左右调节找到通过侧块中线的矢状位图像[8]。在PACS上对每例患者C3~7双侧侧块中点矢状位图像进行测量: ①PSL,侧块头端和尾端之间的距离(图 2);②下极角(LPA): 侧块后表面与下关节突关节面之间的夹角(图 2)。每个参数重复测量3次取其平均值。

图 1 PACS操作主界面 Fig. 1 PACS operation main interface

图 2 PSL(L)和LPA(∠α)测量 Fig. 2 Measurements of PSL(L) and LPA(∠α)
1.3 内固定技术及分组

选取目前常用的4种颈椎侧块螺钉置钉技术(Roy-Camille、Magerl、Riew和Cheng技术)[9-12](表 1)。采用Yang等[13]提出的微型钛板内固定技术,在不破坏关节突前提下计算所需最小PSL,最小PSL为同一侧块同时放置侧块螺钉与微型钛板的最短长度,若计算值小于实际PSL则定义为置钉成功,反之为置钉失败。不破坏关节突需要满足最小安全距离,x(mm)=螺钉长度(mm)/tan∠α(图 2)。根据微型钛板与侧块螺钉位置关系分为上组(微型钛板位于侧块螺钉上方)和下组(微型钛板位于侧块螺钉下方)。

表 1 颈椎侧块螺钉置钉技术 Tab. 1 Cervical lateral mass screw placement technique

本研究采用颈椎后路内固定系统(图 3),参数: 微型钛板横径A为4.8 mm;侧块螺钉直径为3.5 mm;侧块螺钉以置钉角度30°置入侧块时,侧块螺钉与侧块接触面长轴(B)为4.04 mm,以45°置钉时B为4.95 mm。以Magerl技术置钉为例,上组计算方法为PSL(mm)=(A+B/2-1)×2,下组计算方法为PSL(mm)=(x+A/2+B/2+1)×2。

图 3 颈椎后路内固定系统 Fig. 3 Posterior cervical internal fixation system a: 微型钛板正面  b: 微型钛板侧面  c: 侧块螺钉置入左侧面 a: Front view of micro-titanium plate b: Side view of micro-titanium plate c: Lateral mass screw placement in left view
1.4 统计学处理

采用SPSS 26.0软件对数据进行统计分析。连续变量采用Shapiro-Wilk检验是否符合正态分布,符合正态分布的变量以x±s表示,组间比较采用独立样本t检验。分类变量以例数和百分比表示,组间比较采用χ2检验;以P < 0.05为差异具有统计学意义。

2 结果

C3~7两侧侧块PSL和LPA差异无统计学意义(P > 0.05),因此,采用两侧的平均值进行描述。PSL在远端较长,呈先下降后上升趋势,LPA从C3到C7呈逐渐减小的趋势(表 2)。各节段各侧块螺钉技术的上组置钉成功率均高于下组,差异具有统计学意义(P < 0.05,表 3)。且Cheng上组和Riew上组置钉成功率显著高于其他置钉技术上组,差异有统计学意义(P < 0.05,表 3)。总体来看,C3~7上组总置钉成功率为58.1%(1 348枚),C3~7下组总置钉成功率为0.1%(2枚),总上组置钉成功率显著高于下组,差异具有统计学意义(P < 0.05)。

表 2 颈椎各节段PSL和LPA Tab. 2 PSL and LPA of each cervical segment

表 3 各节段置钉情况 Tab. 3 Screw placement in each segment

依据微型钛板与侧块螺钉数据计算得出,Magerl上组所需最小侧块PSL为15.6 mm,Camille上组为13.1 mm,Riew上组为12.5 mm,Cheng上组为11.5 mm。

3 讨论

本研究通过使用PACS测量颈椎侧块相关影像学参数,模拟4种侧块螺钉置钉技术,并比较微型钛板与侧块螺钉放置于不同位置时置钉成功率的改变,以分析微型钛板联合侧块螺钉应用于颈椎后路手术中的可行性。此前,Maeda等[14]的研究显示,部分颈椎损伤患者存在椎间盘和韧带等损伤,与颈椎局部不稳存在显著相关性。因此,在手术治疗时,除了充分广泛减压,还需要考虑恢复颈椎节段的稳定性。颈椎后路单开门微型钛板联合侧块螺钉内固定术广泛应用于临床,常用于治疗合并颈椎不稳的多节段脊髓型颈椎病[6, 15]

以往研究[16-18]表明,在椎板成形术的微型钛板固定中,螺钉侵犯椎间小关节并不罕见,发生率为34.1% ~ 37.4%,由此导致的术后轴性痛引起越来越多学者的关注。Chen等[16]的研究表明,椎板成形术中螺钉侵犯小关节面虽不影响神经功能恢复,但会导致颈椎活动度减小和轴性症状加重,对患者日常生活造成一定影响。

本研究结果显示,C3~7侧块PSL呈先下降后上升的趋势,C4侧块PSL最短;同时,侧块LPA也呈逐渐减小的趋势。值得注意的是,由于远端LPA较小,微型钛板和侧块螺钉在远端节段的放置位置比近端更高,与之前的研究结论相同[13, 19]。同时,为了避免侧块后表面空间不足以同时放置微型钛板和侧块螺钉,术前可先制备侧块螺钉的钉道,然后进行单开门手术,将微型钛板放置在合适的位置上,最后将侧块螺钉拧入钉道中。如果侧块螺钉已置钉完成,放置微型钛板时会受到影响,不利于术中操作,降低了手术的安全性。此术式在临床开展初期,门轴侧置钉偏内时,侧块螺钉钉尾会抵挡棘突,对开门角度有一定限制,随着置钉技术的完善,使侧块螺钉进钉点稍偏外,锁紧螺帽时尽量向外倾斜后锁紧固定,门轴侧棘突做适度的修整,解决了侧块螺钉对开门角度限制问题,增加了椎管矢状径与椎管横截面积,减轻了对脊髓的压迫。还应注意的是,即使对于解剖结构合适的病例,亦应谨慎选择手术适应证,以防止内置物滥用。

Eldin等[20]的研究表明,Camille技术容易侵犯侧块小关节,在颈椎后路单开门微型钛板联合侧块螺钉内固定术中可减少Camille技术的使用,以避免更多的小关节侵犯。本研究结果显示,Riew上组和Cheng上组置钉成功率(69.3%,85.2%)高于Camille上组和Magerl上组,是颈椎后路联合手术中可行且相对安全的置钉方法。

本研究存在以下局限性。首先,侧块后表面不是一个平面,而是一个圆形的曲面,本研究采用的测量方法在这种曲面测量上存在一定误差,在二维图像的限制下,无法准确测量侧块的真实曲面长度。其次,本研究考虑到品牌及螺钉型号对手术的影响,在实验设计阶段对各品牌器械参数及其在手术中的使用情况进行了调研,结果显示,术中大多使用直径为3.5 mm的侧块螺钉,并且很多品牌螺钉在设计上并没有明显的差异。因此,最终选择富乐(中国)和强生(美国)的螺钉进行研究,2种螺钉在外观及参数上基本一致。另外,本研究纳入的病例数量有限,且大多来自辽沈地区,存在一定的混杂因素及选择偏倚。最后,本研究是一项回顾性研究,未来需要进行更大规模或多中心的研究来支持这一结论。尽管如此,本研究理论切实可行,未来本研究组将进一步收集更多颈椎后路单开门微型钛板联合侧块螺钉内固定术相关资料并进行术后随访,以验证其在临床上的可行性。

综上所述,颈椎后路单开门联合手术中,微型钛板置于侧块螺钉上方时置钉成功率较高。其中,Riew上组和Cheng上组的置钉成功率更高,为颈椎后路单开门微型钛板联合侧块螺钉内固定术安全、可行的策略。若颈椎侧块PSL < 11.5 mm,则不建议行联合手术。

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