Transvertebral anterior cervical foraminotomy: midterm outcomes of clinical and radiological assessments including the finite element method

Purpose

The aim of this study was to compare the clinical features, radiological changes, biomechanical effects, and efficacy in patients treated by transvertebral anterior foraminotomy. Preservation of segmental motion and avoidance of adjacent segment degeneration are theoretical advantages of transvertebral anterior foraminotomy. In practice, this procedure is minimally invasive and has shown good clinical results, especially in patients with unilateral cervical radiculopathy.

Method

We conducted a retrospective minimum 2-year follow-up study of the cervical spine of patients treated by transvertebral anterior foraminotomy at our institution. Radiological outcomes, which were estimated by measuring disc and functional spinal unit heights, and the angle and range of motion (ROM) from C2 to C7 of the functional spinal unit and adjacent segments were evaluated. Furthermore, a three-dimensional finite element method was used to biomechanically analyze the strength of the postoperative vertebral body.

Results

Between 2004 and 2009, 34 patients underwent surgery. The improvement rate was 94.2 %. The average flexion–extension ROM from C2 to C7 was 36.6 ± 16.6°. On plain radiographs, the disc height and ROM and height of the functional spinal unit in the operated segment were not significantly decreased relative to the preoperative levels. The finite element method also revealed that there was no difference in strength between the pre- and postvertebral bodies.

Conclusions

These results demonstrate that biomechanical stability was achieved. Transvertebral anterior cervical foraminotomy did not limit motion in the operated and adjacent segments and did not cause a significant decrease in disc and vertebral heights after surgery.     

Anatomic considerations of a modified anterior approach to the cervicothoracic junction

The results of a study on 30 adult human cadavers showed that the anterior aspect of T-3 can be easily exposed through a modified anterior approach to the cervicothoracic spinal junction. Anterior exposure of T-4 caused significant tension on the brachiocephalic vein in 57%; in 7% the vein actually tore. The location of the vital structures is as follows: the left brachiocephalic vein is at T-1 and T-2 in 80%; the aortic arch is at T-2 and T-3 in 90%; the right recurrent laryngeal nerve reaches the tracheoesophageal groove at the level of C-6 in 50%; the thoracic duct empties into the systemic venous system from C-7 to T-2. Adequate exposure of the low cervical to the upper thoracic spine can be obtained with this approach. Preoperative computed tomographic evaluation of the location of the left brachiocephalic vein with respect to the vertebral levels is recommended.     

Mini-open anterior approach to the cervicothoracic junction: a cadaveric study

Purpose

To investigate the feasibility of mini-open anterior approach to the cervicothoracic junction (CTJ) in cadaveric specimens.

Methods

Four adult fresh-frozen cadaveric specimens were used for this study. On the cadaveric specimen, an osteotomy window was made in manubrium sterni to remove the bony obstacle. To bypass the vital vascular and neural structures over the operative field, we used the surgical corridor which was located medially by the brachiocephalic artery and laterally by the right brachiocephalic vein, or in combination with another surgical corridor between the ascending aorta and the superior vena cava. And we used a special self-retaining retractor system and an endoscope to facilitate the procedures.

Results

Surgical procedures performed on the four fresh-frozen cadaveric specimens to expose the CTJ through mini-open anterior approach were successful. The anterior surface of C6–T5 could be exposed, allowing complete decompression and application of locking plate and screws. The most caudal accessible vertebral body was T5 vertebral body in our study.

Conclusion

It is feasible to expose the CTJ through this mini-open anterior approach.     

脊柱颈胸段前路内固定手术相关的影像学测量及其临床意义

目的:通过影像学方法测量脊柱颈胸段前路内固定手术相关的重要参数,为脊柱颈胸段前路手术术前计划的制定以及钢板螺钉内固定物的设计提供参考。方法:自2012年6月至11月,随机选取120例正常成人颈椎MRI正中矢状面影像,男58例,女62例;年龄20～78岁,平均(48.3±13.7)岁。利用PACS系统工作站自带的测量工具,分别测量各个椎体的前、中、后高度和上、中、下矢状径以及各个不同节段的前高度和Cobb角。结果:脊柱颈胸段椎体从头侧向尾侧,前、中、后高度以及上、中、下矢状径逐渐增大(P<0.01)。对单个椎体而言,后高度>前高度>中高度(P<0.01),下矢状径>上矢状径>中矢状径(P<0.01),上位椎体的下矢状径与下位椎体的上矢状径数值较接近。男性受试者脊柱颈胸段Cobb角为(7.61±3.85)°,女性受试者脊柱颈胸段Cobb角为(5.58±2.59)°。结论:在行脊柱颈胸段前路内固定时,建议上位椎体进钉点在椎体中下1/3,螺钉可稍向头侧倾斜,下位椎体的进钉点在椎体的中上1/3,螺钉可稍向尾侧倾斜,并可根据正常成人的Cobb角对钢板进行预弯。     

颈胸段脊柱脊髓伤的诊断及前路手术治疗

目的 探讨颈胸段脊柱脊髓损伤的临床特点、诊断及颈胸段前路减压、植骨、Orion钢板内固定术的治疗作用。方法 分析26例颈胸段脊柱骨折、脱位患者的临床表现;行颈胸段前路C7、T1、C6－7或C7－T1椎体次全切除、植骨及Oron锁定型颈椎前路钢板固定术。结果 颈胸段脊柱脊髓损伤患者通常表现为C8－T1或T2相应节段脊髓神经根症状,10例伴有窦性心动过缓、8例出现低血压、7例出现Horner征等交感节刺激症状。所有患者随访3－20个月,植骨均在3－4个月内完全融合,20例脊髓神经功能有不同程度的改善,上述交感神经节刺激疾病缓解,1术后出现暂时性声音嘶哑。结论 颈胸段脊柱脊髓损伤根据其临床特点、影像学表现可确定诊断;颈胸段前路减压、植骨、Orion钢板内固定术对颈胸段脊柱脊髓损伤具有较好的疗效,Orion钢板有助于植骨节段融合、重建和稳定颈胸段脊柱。     

Comparison of biomechanical response to surgical procedures used for cervical radiculopathy: posterior keyhole foraminotomy versus anterior foraminotomy and discectomy versus anterior discectomy with fusion

The objective of this study was to compare the change in flexibility of C5-C6 caused by three procedures using a three-dimensional nonlinear finite element model: posterior foraminotomy (keyhole procedure), anterior foraminotomy with discectomy, and anterior discectomy with fusion. The keyhole procedure produced a minor increase in motion. The anterior foraminotomy and discectomy produced one to two times greater motion. Anterior discectomy with fusion produced 50% to 100% reduction in motion. The posterior keyhole foraminotomy has a much lesser effect on the stability of the cervical spine segment than does an anterior procedure, and fusion is a requisite part of the anterior decompression procedure.     

改良前方入路结核病灶清除、同种异体骨移植、内固定治疗颈胸段脊柱结核

目的：探讨通过改良前方入路进行颈胸段脊柱结核病灶清除、同种异体骨移植、内固定治疗的疗效.方法：对6例C7～T3椎体结核患者采用标准颈椎前方入路联合胸骨柄正中劈开暴露病灶,彻底清除结核肉芽组织、脓液、死骨等进行脊髓减压,次全切除相应椎体,植入同种异体髂骨块重建前柱、前方钉板内固定,术后佩戴头颈胸支具6个月,正规抗痨12个月.结果：随访18～39个月,平均28个月,6例患者均获骨性愈合,结核病变无复发,后凸角无明显丢失.结论：颈胸段改良前方入路暴露C7～T3病灶充分、安全,病灶清除后植入异体髂骨块修复骨缺损、牢固内固定,重建颈胸段的稳定性、矫正后凸畸形可靠.     

颈胸段脊柱骨肿瘤术后再手术

目的 探讨颈胸段脊柱骨肿瘤术后再手术的因为及其手术策略.方法 2000年7月至2008年1月,对14例颈胸段脊柱骨肿瘤术后患者施行再手术.软骨肉瘤5例,骨巨细胞瘤5例,血管肉瘤、侵袭性骨母细胞瘤、副神经节瘤、动脉瘤样骨囊肿各1例.经前后联合入路行单个椎节切除6例、两个椎节切除2例、三个椎节3例,经后外侧入路行单个椎节切除1例、两个椎节切除2例.除2例三个椎节切除分二期进行外,其余均为一期完成.前路采用钛网或植骨、骨水泥加带锁钉板内固定系统或单棒内固定,后路采用钉棒内固定系统重建.术后血管肉瘤患者接受化疗和局部放疗,其余患者接受局部放疗.结果 术后所有患者局部疼痛均有不同程度缓解,脊髓神经功能改善.3例脑脊液漏,经引流、换药处理后愈合,2例Horner综合征和1例声音嘶哑于术后2～5周自行恢复.随访18～108个月,平均45个月.7例患者分别于术后12～22个月再次复发,其中5例分别于术后30～38个月瘫痪、死亡,2例带瘤生存.结论 颈胸段脊柱骨肿瘤术后再手术的主要因为是肿瘤局部复发或肿瘤残存.复发与肿瘤病理类型、切除方式和相关综合治疗的衔接有关.应该珍惜第一次手术机会,力争将肉眼可见的肿瘤彻底切除.与初次手术相比,再手术具有更高的风险及难度,术者应熟悉颈胸段脊柱的解剖结构.     

Extraspinal ependymoma at the cervicothoracic junction

A case of extraspinal ependymoma at the cervicothoracic junction is reported. Its presentation, histology, origin, prognosis, and treatment are discussed in light of previous experience with extraspinal ependymomas in the sacral region.     

脊柱颈胸段损伤的诊治

脊柱颈胸段（Cervicothoracic Junction）是一个特殊的解剖区域,目前尚无统一明确的定义,通常是指颈椎和胸椎逐渐过渡的区域（一般指C5-T3节段）。有些学者将其严格定义为C7-T1节段。本期我们收集了几篇关于脊柱颈胸段的相关论文,内容包括颈胸段基础研究、颈胸段骨折脱位的治疗、颈胸段急性外伤性椎间盘突出的处理等。     

Managing disorders of the cervicothoracic junction

A wide range of pathologic conditions occur at the cervicothoracic junction. These conditions are usually the result of trauma, neoplastic processes, infection, prior surgery, or degenerative changes. Instability in this region of the spine is difficult to manage, particularly because of the complex biomechanics involved and the challenging surgical approaches required for treatment. Traditional radiologic evaluation of the cervicothoracic junction is often inadequate; as a result, the standard 3-view cervical spine series should be augmented with swimmer's or oblique views. Surgical treatment, designed to increase stability and allow early mobilization and rehabilitation, often requires internal fixation devices; lateral-mass or pedicle screws are increasingly being used to avoid complications associated with devices occupying the spinal canal. Although posterior surgical approaches to the cervicothoracic junction are relatively straightforward, anterior approaches require mastery in traversing the various bony and soft-tissue structures.     

An RCT study on the feasibility of anterior transpedicular screw fixation in the cervicothoracic junction

Study design

We evaluated the trajectory and the entry points of anterior transpedicular screws (ATPS) in the cervicothoracic junction (CTJ).

Objective

This study aimed at investigating the feasibility of ATPS fixation in the CTJ.

Summary of background data

Application of an ATPS in the lower cervical spine has been reported; however, there were no reports exploring the feasibility of anterior transpedicular screw fixation in the CTJ.

Methods

CT scans were performed in 50 cases and multiplanar reformation was used to measure the related parameters on pedicle axis view at C6–T2. Transverse pedicle angle, outer pedicle width, pedicle axis length, distance transverse intersection point (DtIP), sagittal pedicle angle, anterior vertebral body height, outer pedicle height, and distance sagittal intersection point (DsIP) were measured. The prozone of CTJ was divided into three different regions, which were named as the “manubrium region”, the region “above” and “below” the manubrium. The distribution of the trajectory of sagittal pedicle axes was recorded in the three regions and the related data were statistically analyzed.

Results

There was no statistical difference in gender (P > 0.05). The transverse pedicle angle decreased from C6 (46.77° ± 2.72°) to T2 (20.62° ± 5.04°). DtIP increased from C6 to T2. DsIP was an average of 7.17 mm. The sagittal pedicle axis lines of the C6 and C7 were located in the region above the manubrium. T1 was mainly in the manubrium region followed by the region above the manubrium. T2 was mainly located in the manubrium region followed by the region below the manubrium.

Conclusion

Implantation of ATPS at C6, C7, and some T1 is feasible through the low anterior cervical approach, while it is almost impossible to approach T2 that way.

     

后路单开门联合椎间孔切开术与前路减压融合术治疗混合型颈椎病的疗效比较

 目的 通过回顾性病例分析,评价单开门椎板成形联合椎间孔切开术(laminoplasty with foraminotomy, LF )与前路椎间盘切除减压融合术（anterior cervical discectomy and fusion,ACDF）治疗脊髓神经根型颈椎病的临床及影像学疗效。方法 自 2008 年 1 月至 2010 年 1 月,按照纳入及排除标准选取 68 例患者纳入研究,ACDF 组 33 例,LF 组 35 例,随访均超过 2 年。疗效评估采用日本骨科协会（Japanese Orthopedic Association,JOA）评分及改善率,影像学评估采用 X 线片测量颈椎曲度和颈椎活动度（range of motion, ROM）,末次随访时采用颈椎功能障碍指数量表（neck disabilitv index,NDI）评估两组患者颈肩部疼痛的改善程度。结果 ACDF 组手术时间平均 187 min、出血量平均为 127 ml,与 LF 组（154 min、235 ml）比较,差异均有统计学意义（t _手术时间=4.170,P=0.000;Z _出血量=-6.888,P=0.000）。术后两组下肢感觉改善率（ACDF 组 64.0%、 LF 组 66.0%）的差异有统计学意义（Z=-7.512,P=0.000）,而上肢运动、上肢感觉及下肢运动改善率的差异均无统计学意义。术后 3 个月时 ACDF 组出现 1 例植骨不融合,随访 2 年时 3 例出现邻近节段退变;而 LF 组未见并发症出现。末次随访时 ACDF 组在提物（Z=-3.947, P=0.000）及开车（t=-7.523,P=0.000）方面的 NDI 疼痛评分低于 LF 组。ACDF 组颈椎曲度由术前平均 13.7°增加至 16.2°,而 LF 组由 14.6°降至 13.3°（Z=-3.374,P=0.001）。两种术式均导致术后颈椎 ROM 下降（ACDF 组 14.8°、LF 组 16.5°）,但差异有统计学意义（t=-2.167,P =0.034）。结论 LF 在改善长节段颈椎间盘突出所致的颈椎髓性症状及根性症状方面与 ACDF 的临床效果相近,但具有手术时间短、手术技术相对简单、近期并发症发生率低等优势,是治疗混合型颈椎病安全、有效的手术方式。     

Zero-P椎间融合器在颈胸交界处椎间盘突出症治疗中的应用效果

目的:探讨Zero-P椎间融合器在颈胸交界处椎间盘突出症颈前路手术治疗中的应用及疗效。方法 :2012年8月~2015年8月,我院采用颈前路减压结合Zero-P椎间融合器置入治疗的颈胸交界处椎间盘突出症患者9例,其中男5例,女4例,年龄34~69岁,平均49.65±5.73岁;病程3~18个月,平均5.37±3.63个月。CT及MRI均显示明显的椎间盘突出及脊髓受压,MRI显示多节段颈椎椎间盘突出5例(2例为C4/5、C7/T1,2例为C6/7、C7/T1,1例为C3/4、C4/5、C7/T1),单节段颈椎椎间盘突出4例(C7/T1)。术前通过X线、CT和MRI进行评估,所有入选的病例其胸骨切迹水平所对的椎体高度均位于突出间隙下位椎体以下。采用日本骨科协会(Japanese Orthopedic Association,JOA)评分法、疼痛视觉模拟评分(visual analogue scale,VAS)和颈椎功能障碍指数(neck disability index,NDI)评价临床治疗效果,术后常规影像学检查评估植骨愈合情况。结果:全部患者手术顺利,所有突出节段均获得良好减压、融合。术中减压及内固定放置顺利,均未出现脊髓、硬膜损伤,未出现脑脊液漏、感染等严重并发症。随访时间平均24个月(12~36个月),中位随访时间为25个月。患者的VAS及NDI术前分别为7.06±1.64分和43.27±4.53分,术后12个月时分别为2.02±1.38分和8.64±2.37分,均较术前明显改善(P0.05);患者术前JOA评分为6.94±1.57分,术后12个月随访时改善为13.14±1.62分,差异有统计学意义(P0.05)。在术后随访颈椎X线片中未发现内置物沉降、螺钉松动、断裂和移位等并发症的发生。所有患者在末次随访时均达骨性融合。结论:采用颈前路减压结合Zero-P椎间融合器置入治疗颈胸交界处椎间盘突出症能够获得良好的减压和固定,获得满意的临床效果。     

Fractures and dislocations of the cervicothoracic junction

Presented is a retrospective review of case notes and all available imaging studies in seven patients with acute fractures-dislocations of the cervicothoracic junction. Imaging studies included radiographs (five cases), computed tomography (six cases), and magnetic resonance imaging (seven cases). The study group consisted of five men and two women with mean age at presentation of 43.6 years (range 25-69 years). Four patients had been in road traffic accidents, whereas three patients had had falls. Three patients sustained complete neurologic deficits with no recovery, whereas the remaining four had no abnormal neurology or mild deficit at presentation and were normal at final follow-up. The injury was missed initially in three cases. The commonest injury pattern was traumatic spondylolisthesis of C7 on T1 with multilevel neural arch fractures, resulting in increased anteroposterior canal dimensions (four cases). Bilateral pars fractures of C7 and pure facet dislocation were seen in one case each. Neurologic deficit was related to the degree of anterior displacement of C7 on T1. Fracture-dislocation at the cervicothoracic junction is a rare injury with a variation of injury patterns and neurologic outcome.     

There is no increased risk of adjacent segment disease at the cervicothoracic junction following an anterior cervical discectomy and fusion to C7

Background Context

Anterior cervical discectomy and fusion (ACDF) is a very common operative intervention for the treatment of cervical spine degenerative disease in those who have failed non-operative measures. However, studies examining long-term follow-up on patients who underwent ACDF reveal evidence of radiographic and clinical degenerative disc disease at the levels adjacent to the fusion construct. Consistent with other junctional regions of the spine, the cervicothoracic junction (CTJ) has significant morphologic variations. As a result, the CTJ undergoes significant static and dynamic stress. Given these findings, there has been some thought that ACDF down to C7 may experience additional risks for adjacent segment degeneration/disease (ASD) when compared with ASDFs that are cephalad to C7.

Anatomy of the neck and cervicothoracic junction

All thoracic surgeons must have an extensive knowledge of the anatomy of the neck, because cervical approaches are used on an almost daily basis to access the cervical trachea, upper esophagus, and superior mediastinum. In addition to basic and scholarly knowledge of anatomy, they also must understand the anatomic relationships among the neck, the mediastinum, and both pleural spaces. Indeed, such knowledge forms the basis for the diagnosis and management of many aspects of pulmonary, mediastinal, and esophageal pathologies.