【专题文献】之胸腰椎骨折——撑开和韧带整复复位后路器械固定

Thoracolumbar Fracture: Posterior Instrumentation Using Distraction and Ligamentotaxis Reduction
胸腰椎骨折：采用撑开和韧带整复复位后路器械固定


Thoracolumbar burst fracture occurs when the vertebral body is subjected to a significant axial force that brings about compression failure of the anterior and middle columns of the spine.1 Most burst fractures involve the thoracolumbar junction, which is uniquely susceptible to this type of injury because of its transitional anatomy and its location between the stiff, kyphotic thoracic spine and the more mobile, lordotic lumbar region. Unlike purely compressive fractures, in which the middle spinal column remains intact, burst injuries typically are associated with some degree of spinal canal occlusion, which may result in neurologic deficits.
当椎体受到轴向暴力产生脊柱前、中柱压缩破坏时可发生胸腰椎爆裂性骨折。大多数爆裂性骨折容易发生在胸腰段连接处，主要是因为胸腰段解剖结构和所处位置不同，胸段特点是活动度小并向后凸，而腰段活动度较大且向前凸。单纯性压缩性骨折时脊柱中柱保持完好，而典型的爆裂性损伤与单纯压缩骨折不同，它可发生一定程度的椎管受累，从而导致神经功能障碍。
Many stable thoracolumbar burst fractures are treated nonsurgically with external immobilization and early ambulation. However, the patient who exhibits spinal instability, progressive spinal deformity, or an incomplete spinal cord injury is often an appropriate candidate for surgical intervention. In these presentations, the goals of surgery are to restore spinal stability through fracture stabilization and to improve functional outcomes by decompressing the neural elements.
许多稳定的胸腰段爆裂性骨折采用制动和早期下床活动等非手术治疗。然而对于脊柱不稳定、进行性脊柱畸形或不完全性脊柱损伤的患者通常适合手术治疗。对这些情况进行手术的目的在于通过稳定骨折恢复脊柱的稳定性、通过减压改善神经功能。
There is a great deal of controversy regarding the optimal surgical approach (ie, anterior, posterior, circumferential) for treating a patient with a thoracolumbar burst fracture. Posterior instrumentation techniques are frequently used in this clinical scenario because they facilitate fracture reduction and subsequent arthrodesis. At the same time, indirect decompression of the spinal canal may be accomplished through distraction and ligamentotaxis, a process that effectively shifts the retropulsed bony fragments anteriorly away from the neural structures. The posterior-only approach has become even more popular with the development of modern pedicle screw systems, which provide reliable fixation through the anterior, middle, and posterior columns, thereby increasing the rigidity of these constructs and allowing application of greater axial and rotational forces to the spine.
关于最佳手术入路(如前路、后路、前后联合)治疗胸腰椎爆裂性骨折患者存在大量争议。在临床上后路器械固定技术通常用于此类患者，这种手术方式有利于骨折复位和融合。同时，撑开和韧带整复可以完成椎管间接减压，这种方法有效后复位骨折碎片，使其远离神经结构。随着现代椎弓根螺钉系统的发展，后方入路变得更加普及，它通过前、中和后柱提供可靠的固定，因此增加了这些结构的刚度，脊柱可承受更大的轴向和旋转暴力。

Indications and Contraindications
适应证和禁忌证
The optimal surgical approach for the patient with a thoracolumbar burst fracture is determined by neurologic status, presence of a kyphotic deformity, evidence of spinal canal compromise or instability on imaging studies, and presence of other nonspinal injuries. Isolated posterior instrumented spinal fusion is best suited for an unstable burst fracture in the patient with no neurologic deficit and in whom direct decompression is unnecessary. A posterior procedure also may be indicated for an acute burst fracture associated with either neurologic injury or moderate spinal canal occlusion in which distraction and ligamentotaxis may result in the indirect reduction of the displaced bony fragments.
胸腰段爆裂性骨折患者的最佳手术方式取决于神经状况、有无后凸畸形、有无椎管受累或影像学上的不稳、有无其他非脊柱损伤。单独后路器械脊柱融合是无神经功能障碍不稳定爆裂性骨折患者的最佳适应证，这些患者不需要行直接减压。后路手术也适用于存在神经损伤或中度椎管狭窄的急性爆裂性骨折，撑开和韧带可以间接复位复位骨折碎片。
Several studies have demonstrated that distraction in conjunction with ligamentotaxis may reduce spinal canal compression by up to 50%, usually to <20% of the total area.2-5 Flexion-distraction and soft-tissue Chance injuries with disruption of the posterior ligamentous complex also may be addressed with this technique, in which the instrumentation supplements the deficient posterior tension band. Likewise, successful reduction and stabilization of fracture-dislocations and shear injuries with extensive translational or rotational instability is more easily achieved using posterior pedicle screws.
已有研究表明撑开联合韧带整复可以复位椎管压迫至50%，通常小于总面积的20%。屈曲牵拉和存在后方韧带复合体断裂的软组织Chance损伤也可以采用这项技术，器械固定可以弥补后方张力带缺失。同样，采用后路椎弓根钉可以更容易获得骨折脱位、存在广泛平移或旋转不稳定的剪切力损伤的成功复位和稳定。
In the patient with complete thoracic-level spinal cord injury with relatively limited potential for meaningful neurologic recovery, posterior arthrodesis may be indicated to maintain proper alignment, prevent the progression of further deformity, and provide immediate stability. The latter is essential for nursing care and rehabilitation. This strategy also may be considered for a fracture involving the posterior elements that is accompanied by neurologic deficit, for which a laminectomy may be necessary to release entrapped roots or repair traumatic dural tears.
为给完全性胸髓损伤的患者提供神经功能恢复的相对有限的可能性，后路融合可以恢复脊柱正常序列、预防畸形进一步发展并提供即刻的稳定性，接下来需要重视护理和康复治疗。这种方案也可以用于后方结构合并神经功能受损的骨折，为松解卡压神经根或修复创伤性硬膜撕裂需行椎板切除术。
Rarely, a burst fracture involving the upper thoracic spine (ie, between T2 and T4) may require posterior decompression because of anatomic constraints that preclude a direct anterior approach via thoracotomy. Finally, because the posterior approach to the spine avoids the substantial morbidity associated with an anterior thoracolumbar exposure, this surgical approach in conjunction with posterior stabilization may be the only available treatment option in the multitrauma patient with significant thoracic or abdominal injuries.
由于解剖原因，上段胸椎爆裂性骨折(如T2-T4)直接行前路手术需要开胸，因此一般需行后路减压。最后，由于后路可避免前路胸腰段暴露相关的并发症发生，后路稳定胸腰段可能是明显胸部或腹部损伤的多发伤患者可行的唯一治疗方案。
These indirect reduction techniques are not as effective in the patient with thoracolumbar fracture resulting in >67% compromise of the spinal canal because the annular ligament attachments to the extruded fragments are less likely to be intact. 6 Several reports have shown that the results of posterior decompression with distraction and ligamentotaxis deteriorate as early as 3 days after the traumatic event. This suggests that this intervention must be completed promptly before any fracture consolidation has occurred. 2,7 Posterior fusion with pedicle screws may not be feasible in the patient whose pedicles exhibit aberrant morphology, insufficient bony dimensions, or fracture. All of these may be apparent on preoperative axial imaging.
在椎管狭窄>67%的胸腰段骨折患者采用这些间接复位技术效果不太好，因为椎体周围韧带与突出的骨折块粘在一起，几乎均受到损伤。一些报道结果显示后路减压联合撑开和韧带整复在创伤后3天内发生病情恶化，因此认为这种干预技术在骨折发生愈合前快速完成。后路椎弓螺钉固定融合可能并不适用于椎弓根形态异常、椎弓根太小或骨折的患者。所有这些在术前轴位像上可观察清楚。

Surgical Technique
手术技术
Patient Evaluation
患者评估
Successful treatment of the patient with a thoracolumbar burst fracture is contingent on the accurate classification of the injury according to patient history, physical examination, and radiographic findings. The Denis and AO classification systems for thoracolumbar fracture are currently the most widely accepted, but they are known to exhibit only fair inter- and intraobserver reliability.8,9 To address these deficiencies, Vaccaro et al10 recently developed the Thoracolumbar Injury Classification and Severity Score (TLISS) method to more precisely define fracture stability and guide subsequent management. The validity and reproducibility of this model have been corroborated based on injury morphology, the integrity of the posterior ligamentous complex, and the neurologic status of the patient.
胸腰段爆裂性骨折患者的成功治疗需要根据病史、体格检查和放射学表现对损伤进行准确分类。目前，胸腰段爆裂性骨折的Denis和AO分类系统忆被广泛接受，但是它们仅用于确定观察者间和观察者内的可靠性分析。为了弥补这些分类的不足，最近Vaccaro等提出胸腰段损伤分类和严重性评分(TLISS)，更加准确地规定骨折稳定性并指导后续治疗。这种模型基于损伤形态学、后方韧带复合体完整性和患者神经功能，其有效性和可重复性已得到确证。
The complete battery of diagnostic studies must be carefully scrutinized as part of the preoperative planning process. Because plain radiographs may underestimate spinal canal compromise by as much as 20%, computed tomography scans are indispensable for assessing vertebral body comminution and bony anatomy prior to reconstruction.11 Magnetic resonance imaging also may be useful for evaluating the ligamentous structures as well as any pathologic conditions, such as disk herniation, myelomalacia, and epidural hematoma.
一系列完整的、精心的诊断学分析必须作为术前计划的一部分。因为平片可能对椎管狭窄达20%时估计不足，必须在功能重建前采用CT扫描来评估椎体粉碎情况和骨解剖形态。MRI也可以用于评估韧带结构和其他病理状态如椎间盘突出、脊髓软化和硬膜外血肿。
Patient Positioning and Surgical Exposure
患者体位和手术暴露
Following general endotracheal tube intubation, the patient is carefully log rolled prone on a radiolucent frame (eg, Jackson table). All bony prominences are padded to prevent skin breakdown, and the abdomen is left unsupported to decrease intra-abdominal pressure and minimize bleeding from the epidural venous plexus. To prevent injury to the brachial plexus or peripheral nerves, the shoulders should not be abducted >90°. The knees are placed in a slightly flexed position to relieve any traction on the sciatic nerves. Fluoroscopy should be available for pedicle screw placement, and adequate visualization of the fractured segment should be confirmed before proceeding. In the patient who is neurologically intact or who has an incomplete spinal cord lesion, we recommend intraoperative monitoring of somatosensory and transcranial electric motor-evoked potentials to provide instantaneous physiologic data during reduction maneuvers and instrumentation.
气管内插管全身麻醉后，滚动翻身将患者俯卧于可透视手术台(如Jackson手术台)。垫好所有骨突起以预防皮肤受损，架空腹部以降低腹内压力和减少硬膜外静脉丛出血。为了预防臂丛或外周神经损伤，肩部外展不能>90°。膝部置于轻度屈曲位以减轻对坐骨神经的任何牵拉。术前采用X线透视定位椎弓根，确定骨折块充分显影。在神经未受损伤的患者或不完全性脊髓损伤患者，我们建议在手法和器械复位过程中采用术中体感诱发电位和经颅运动诱发电位监测以提供即时生理数据。
The patient is prepped and draped in a sterile fashion. The surgical site should incorporate the iliac crests when the surgeon anticipates the need to harvest autogenous bone. A standard midline skin incision centered over the spinal fracture is made, and the subcutaneous tissues are divided down to the level of the deep fascia. The fascia is incised on both sides of the spinous processes, and a subperiosteal exposure is performed laterally beyond the facet joints to the tips of the transverse processes that lie within the intended fusion construct.
患者常规消毒、铺巾。当外科医生预期需要采用自体骨移植时，手术准备范围应该包括髂嵴。采用脊柱骨折段标准正中皮肤切口，分离皮下组织至深筋膜水平。在棘突两侧切开筋膜，采用骨膜下暴露关节突关节外侧直至横突尖部，包括需要融合的节段。
Pedicle Screw Instrumentation
椎弓根螺钉技术
The landmarks for pedicle screw placement are the transverse process, the pars interarticularis, and the facet joint (Figure 1) ( video step 1). In the thoracic spine, the starting point is located lateral to a vertical line bisecting the facet joint along the upper one third of the transverse process. Lumbar pedicles may be accessed along the lateral aspect of the facet joint, where they intersect a line passing through the middle portion of the transverse process. A high-speed burr is advanced 3 to 5mm into the bone, and a curet or awl is inserted to cannulate the pedicle. Fluoroscopy is used to verify angulation in all planes ( video step 2). The continuity and end point of the tract are palpated with a probe to ensure that there are no cortical breaches through any of the pedicle walls. The screw diameter may be estimated by measuring the dimensions of the pedicle on preoperative axial computed tomography scans, and screw length may be determined using a depth gauge. As the appropriately sized screw is being introduced, lateral fluoroscopy may be used to adjust its trajectory in the sagittal plane.
椎弓根螺钉置钉点的标志在横突、椎弓根峡部和关节突关节 (图1)。在胸椎，进钉点位于关节突关节中点的垂线和横突上1/3水平线的交点。腰椎椎弓根的进进钉点位于关节突关节外缘垂直延长线与横突中轴水平线交点。用高速磨钻在骨上预先磨掉3-5mm，刮匙或尖锥进入中突的椎弓根。X线透视证实各个平面的角度。采用探针探测钉道的连续性和终板以确保没有各椎弓根侧壁有皮质破损。螺钉直径可通过术前测量轴向CT扫描的椎弓根径进行估计，螺钉长度可能过测深尺确定。当合适规格的螺钉置入后，采用侧位X线透视调整矢状平面的钉道。

Determining the number of levels to instrument and include in the arthrodesis is controversial. In general, longer fusion constructs that extend at least two levels above and below a burst injury provide greater stability. This may be important for fractures with significant comminution or with associated kyphotic deformity. Short-segment fixation limited to the vertebral bodies immediately adjacent to the fracture site is not usually rigid enough to withstand the biomechanical forces present at the thoracolumbar junction, based on the high rate of hardware failure and progressive deformity that has been reported with this type of management. 12 However, it may be an appropriate technique for fractures in the lower lumbar spine or for the patient undergoing combined anteriorposterior fusion.
器械固定及融合节段水平数仍有争议。总的来说，长节段融合包括爆裂性骨折椎体上方和下方各两个节段，它可提供更好的稳定性，这对严重粉碎性骨折或伴随后凸畸形的患者显得重要。短节段固定固定紧邻骨折椎体的节段，通常导致刚度不足以承担胸腰段结合部存在的生物机械力，根据报道短节段固定会导致内固定物失败率高和进行性畸形。然而，短节段融合技术可用于下腰椎或前后路联合融合的患者。
Rod Placement and Distraction/Ligamentotaxis Reduction
安装连接棒和撑开/韧带整复复位
Following placement of all of the screws, the rods are sectioned so that they span all of the instrumented levels. The rods are carefully contoured to reproduce the normal sagittal curvature of the thoracolumbar spine ( video step 3). The curvature of the rod determines the degree of deformity correction; thus, accurate contouring is necessary to prevent displacement at the fracture site. To avoid postoperative flat back syndrome, the rod should be straight in the coronal plane and should restore physiologic alignment in the sagittal plane.
所有螺钉置入后剪棒，棒的长度跨越所有内固定节段。仔细预弯棒以适应正常胸腰段正常矢状面弧度。棒的弧度决定畸形矫正的程度，因此精确预弯棒对预防骨折部位位置不正是必需的。为了术后平背综合征，棒的冠状面应呈笔直，同时恢复矢状面的生理序列。
Although it may be easier to introduce the rods into the heads of polyaxial screws, fixed monoaxial screws are favored in most cases because they deliver greater distractive forces for deformity correction. The AO internal fixator is another specialized device consisting of transpedicular Schanz screws and fully threaded rods. These are joined by a coupling mechanism that is freely mobile in the sagittal plane, allowing for the restoration of normal lordosis of the lumbar spine without any loss of axial height.
虽然棒更容易引入万向螺钉头，对多数病例来说，固定单向螺钉更加有利，因为单向螺钉提供更大的撑开力来矫正畸形。AO内固定器械是另一种特殊的设备，包括经椎弓根Schanz螺钉和全螺纹钢棒，这种器械加入了耦合机制，在矢状面可以自由活动，并考虑到恢复腰椎的正常前凸而没有任何轴向高度丢失。
Once the rods are secured within the pedicle screws using connecting caps, the caudal ends are fixed, and distraction is applied across the fracture (Figure 2) ( video step 4). This maneuver serves to reconstitute vertebral body height and tension the anulus and posterior longitudinal ligament, giving rise to an anteriorly directed force that indirectly reduces the retropulsed fragments by ligamentotaxis (Figure 3). Distraction alone may actually exacerbate any preexisting kyphotic angulation; thus, careful attention also must be directed toward generating concomitant lordosis and reestablishing sagittal balance.
一旦采用连接螺帽将棒安全引入椎弓根螺钉后就固定尾端，通过骨折部位进行撑开(图2)。这种手法旨在重新恢复椎体高度，通过韧带整复牵张纤维环和后纵韧带，在前方产生一种直接力量从而间接复位向后突出的骨折块(图3)。事实上单纯撑开可以加重任何已经存在的后凸角度，因此需要小心谨慎预防产生脊柱前凸、重建脊柱矢状面平衡。

The remaining connecting caps are tightened over the rods, and the entire segment is locked in this lengthened position to maintain the fracture reduction. We recommend linking the rods with cross connectors at both ends to increase the rigidity of the construct. Following reduction, fluoroscopy is used to confirm the final position of the instrumentation and to assess spinal alignment in both the sagittal and coronal planes.
拧紧棒上其余的连接螺帽，在确定的长度锁定整个节段以维持骨折复位。我们建议在棒的两端采用横连接杆以增加重建的刚度。复位后，X线透视以确定固定器械的最终位置，并在矢状平面和冠状平面评估脊柱序列。
Fusion Bed Preparation and Postoperative Care
植骨床准备和术后护理
The laminae and facet joints at the levels to be fused are cleared of all soft tissues and decorticated using gouges or a high-speed burr. After meticulous hemostasis has been achieved, the entire surgical field is irrigated, and bone graft material is packed along all of the exposed bone surfaces. A drain is placed, and the wound is closed in layers. Postoperatively, the patient is encouraged to ambulate as soon as possible and is immobilized in a thoracolumbosacral orthosis for 3 to 6 months.
清除需要融合节段的椎板和关节突关节上所有的软组织，采用骨凿或高速磨钻去皮质处理。彻底止血后，冲洗整个术野，在所有暴露骨表面填充骨移植材料。放置引流，逐层关闭切口。术后鼓励患者尽早走动，采用胸腰骶矫形支具制动3-6月(经boneking提醒后修改)。

Outcomes
效果
Two recent randomized, prospective trials compared the results of patients undergoing surgical versus nonsurgical treatment of stable thoracolumbar burst fractures without neurologic involvement.5,13 No significant differences were found between the two groups. In contrast, unstable injuries and those associated with neurologic deficit are more likely to benefit from surgical intervention, which may be performed anteriorly, posteriorly, or through a combined approach. Although there are currently no convincing data establishing the superiority of any one technique, it has been shown that many thoracolumbar fractures treated posteriorly exhibit excellent overall results with minimal complications. 14 Several authors have suggested that posterior distraction instrumentation and ligamentotaxis may yield clinical and radiographic outcomes similar to those observed following anterior or circumferential procedures for unstable burst injuries.15-17 However, because the anterior spinal column injury cannot be reconstituted by transpedicular screw fixation alone, a posterioronly approach may predispose the individual with vertebral body disruption to instrumentation failure and progressive loss of sagittal alignment. 18,19 Additional prospective randomized controlled studies are needed to determine the optimal surgical strategy for these types of fractures.
最近两个随机前瞻性试验比较了手术和非手术治疗无神经受累的稳定性胸腰段爆裂性骨折的疗效。两组间无显著性差异。相反，不稳定损伤或伴随神经功能障碍时手术治疗效果更好，手术方式可采取前路、后路或前后联合入路。虽然目前没有确切的数据表明任何一项技术的优势，但采用后路治疗的许多胸腰段骨折表明治疗效果良好、并发症少。有作者认为后路撑开器械和韧带整复可以产生与前路或前后路联合手术治疗不稳定爆裂性骨折相似的临床和影像学结果。然而，由于经单纯椎弓根螺钉固定不能重建脊柱前柱损伤，后路固定可能更易导致椎体爆裂患者内固定失败、矢状序列进行性丢失。因此，需要进一步进行前瞻性随机对照研究以确定此类骨折的最佳手术方案。
Although the treatment of thoracolumbar burst injury using posterior stabilization and indirect reduction has been shown to be relatively safe, this technique may give rise to several adverse events. The incidence of iatrogenic neurologic deficits has been reported to be 1%; these may occur intraoperatively during the placement of instrumentation or secondary to the inadvertent manipulation of the spinal cord or roots.20 The neural elements also may be compressed by a postoperative epidural hematoma. Violation of the anterior cortex during insertion of pedicle screws has the potential to damage vascular or visceral structures, which may have devastating consequences if not recognized immediately. Approximately 10% of thoracolumbar fractures become infected following posterior surgery. Infection requires aggressive management with culture-specific antibiotics as well as open irrigation and débridement, when necessary.21 All dural tears, whether traumatic or iatrogenic, should be closed primarily or reinforced with a dural patch if a watertight repair cannot be obtained. Persistent cerebrospinal fluid leaks may necessitate prolonged recumbency or even the introduction of a lumbar subarachnoid drain. As forces are applied to the fractured segment posteriorly in an attempt to achieve reduction through ligamentotaxis, it is possible to overdistract the anterior column, which may lead to increased rates of pseudarthrosis and hardware failure. Both of these complications may result in chronic pain or recurrent deformity. Excessive blood loss may be poorly tolerated by patients with thoracolumbar spine fracture who have limited metabolic reserve because of the presence of other critical injuries.
虽然采用后路固定和间接复位胸腰段爆裂性骨折比较安全，但这项技术可能产生一些不良事件。据报道其医源性神经功能障碍的发生率为1%，可以发生在术中器械置入过程或继发于对脊髓或神经根的不慎操作。神经也可能由于术后硬膜外血肿压迫受到损伤。在置入椎弓根螺钉过程中可能突破椎体前方皮质损伤血管或腹腔脏器，如果没有即刻发现可以导致灾难性后果。后路后术后大约10%的胸腰段骨折发生感染。感染后需要积极处理，结合细菌培养选择敏感抗生素治疗，必要时需要切开引流或清创。所有硬膜撕裂，不管是创伤性还是医源性都需要一期关闭，如果不能修复则需要采用硬膜补片加强。当试图采用韧带整复复位后方骨折片时，有可能导致前柱过度撑开，从而增高假关节发生率和内固定失败率。这两种并发症可能导致慢性疼痛或畸形复发。由于胸腰段骨折患者存在其他急性损伤而导致代谢储备有限，大量失血可能导致其采耐受力降低。

Summary
总结
Although most thoracolumbar fractures are adequately treated nonsurgically, some may require surgery to facilitate functional rehabilitation and enhance patient outcomes. The posterior-only approach has become a well-accepted method for managing unstable thoracolumbar burst fracture with or without an associated neurologic deficit. When performed properly, the application of distractive forces to a posterior construct may indirectly reduce retropulsed fragments through ligamentotaxis and effectively improve the degree of spinal canal occlusion. Nevertheless, the primary goals of this procedure are sagittal realignment and fracture stabilization rather than decompression of neural elements.
虽然大部分胸腰段骨折可采用非手术治疗，但是有一些需要采用手术促进功能恢复、提高患者疗效。单独采用后路已经作为一种广泛接受的方法治疗伴或不伴有神经功能障碍的不稳定性胸腰段爆裂性骨折。恰当应用撑开力和韧带整复间接复位后突骨折片可以有效改善椎管狭窄程度。然而，这种手术的主要目的是恢复矢状序列、稳定骨折而不是神经减压。
The successful implementation of posterior techniques is contingent upon a thorough knowledge of spinal anatomy as well as an understanding of the pathomechanics underlying a specific injury pattern. To minimize the risk of iatrogenic neurologic injury and other complications, posterior instrumentation and subsequent reduction maneuvers should be performed only by the experienced spine surgeon. The appropriate indications for managing thoracolumbar burst fracture posteriorly will be more clearly elucidated once prospective randomized controlled clinical studies comparing the various surgical approaches have been completed.
后路技术的成功应用需要关于脊柱解剖的大量知识、对特殊损伤模式病理力学的理解。为了最小化医源性神经损伤的危险性和其他并发症，后路器械和手法复位应当由有经验的脊柱外科医师进行。一旦比较不同手术方式的前瞻性随机对照临床研究完成，术前需要更加清楚制定恰当的手术适应证，以利于术后更好处理胸腰段爆裂性骨折。

参考文献(略)