球囊辅助复位在高能量爆裂骨折中的应用.doc

Balloon-Assisted Fracture Reduction in High-Energy Burst Fractures球囊辅助复位在高能量爆裂骨折中的应用Dalip Pelinkovic, MD,* Ranjith Kamal Udayakumar, MD, and Frank M. Phillips, MD*The combination of percutaneus vertebral augmentation with posterior instrumentation may be an attractive treatment option for certain high energy burst fractures. Biomaterials such as calcium phosphate cement are biocompatible, share similar biomechanical properties to bone, and are gradually replaced by host bone tissue. Early biomechanical and clinical results indicate that the anterior column may be restored without the need of a traditional anterior surgical approach. Further clinical studies are needed to conrm that this less invasive approach improves patient outcome. Semin Spine Surg 22:67-72 2010 Elsevier Inc. All rights reserved.对于某些高能量爆裂骨折而言，经皮椎体增强联合后路器械固定是一个很有吸引力选择。有些生物材料，如磷酸钙骨水泥，具有良好的生物相容性，与骨的生物力学特性相似，可以逐渐被宿主骨替代。早期生物力学和临床结果显示，前柱获得了恢复，不需要再进行传统的前路手术。还需要更多的临床研究来证实这种微创方法对患者结果的促进作用。KEYWORDS burst fracture, percutaneus, balloon-assisted, reduction关键词：爆裂骨折，经皮，球囊辅助，复位。high-energy thoracolumbar burst fractures can be treated with decompression and anterior, posterior, or circumferential fusion. Traditionally, reconstruction of the posterior tension band with a rod hook or rod screw construct is applied to assist in providing stability and reestablishing the sagittal balance. Ligamentotaxis may also assist in reducing the vertebra. Despite excellent initial fracture reduction, inadequate anterior column support may lead to loss of reduction, poor long-term xation, or even failure of treatment over time.1-3 Insufciency of the anterior column is caused by both the vertebral body fracture and also migration of the disk tissue through the endplate into the fractured vertebral body, which may not be restored with indirect reduction through posterior instrumentation.4 More extensive anterior procedures, such as anterior instrumentation and strut grafting, or cage implantation may successfully restore the anterior spinal column support and are proven to be effective and spare motion segments.5,6 However, anterior procedures are more invasive and are associated with increased hospitalization, blood loss, increased surgical morbidity, or even mortality.5 高能量胸腰椎爆裂骨折常采用减压，前路、后路或环形融合进行治疗。传统后侧张力带结构常采用钩棒或钉棒结构来提供稳定和重建矢状面平衡。韧带整复术有助于复位椎体。尽管早期复位非常好，如果前柱支持不足，可能导致复位丢失、内固定失效、甚至治疗失败。前柱缺损可由于椎体骨折和椎间盘组织经终板嵌入骨折椎体引起，而这是无法通过后路器械进行间接复位的。通过更广泛的前路手术进行器械固定支撑、cage植入等方法可以有效恢复前柱支撑，减少节段活动。但是前路手术的创伤较大，且住院时间更长，出血更多，增加了外科手术率，甚至病死率。Recently, percutaneous instrumentation combined with percutaneous vertebral body augmentation (kyphoplasty/ vertebroplasty) has been added to the surgical armamentarium. In osteoporotic vertebral fractures, kyphoplasty has proven to be a safe procedure with excellent outcomes.7 However, the pathoanatomy of a high-energy burst fracture is distinct from osteoporotic vertebral fractures. Three fracture patterns-wedge, crush, and biconcave-have been described in the osteoporotic patient.8,9 The posterior wall and endplates are mostly intact. In addition, the osteoporotic bone with decreased number and connectivity of trabeculae allows restoration of the vertebral height as balloon tamp ination compresses the soft cancellous bone and elevates the end plates.7,10近来，经皮器械和经皮椎体增强技术（后凸成形和椎体成形术）已成为外科手段。对于骨质疏松性骨折，后凸成形术已被证实是十分安全有效的。然而高能量爆裂骨折与骨质疏松性骨折的病理解剖是不同的。骨质疏松性骨折有三种骨折形式：楔形、爆裂、双凹，后壁和终板多数是完整的。而且，骨质疏松的骨骼由于骨小梁减少，连接力降低，当球囊扩张时，可挤压松软的松质骨，抬高终板，从而恢复椎体高度。In contrast, high-energy traumatic burst fractures are usually caused by substantial axial loading, which results in compression failure of at least the middle and anterior spinal column. The sudden axial load results in a vertebral endplate failure as adjacent disk tissue is driven into the vertebral body. The vast majority of burst fractures cause some canal compromise, typically because of osseous fragments from the superior endplate. Determinants of instability are progressive neurological decit, progressive kyphosis, radiographic evidence of substantial posterior column instability, greater than 50% loss of vertebral body height in association with kyphosis. Fractured and depressed endplates increase the chance of disk displacement into the vertebral body with subsequent focal spinal deformity and failure of the treatment. Consequently, the combination of indirect reduction of thoracolumbar burst fractures with balloon-assisted endplate reduction may recreate a stable anterior column, and stable endplates with long-term maintenance of the sagittal alignment (Fig. 1). Advantages of minimal invasive techniques are quicker recovery, less pain, decreased surgical morbidity, and potentially a more stable construct than isolated posterior or anterior stabilization because of less tissue disruption.相反，高能量爆裂骨折通常由巨大的轴向负荷引起，至少可使前柱和中柱的压缩破坏。突然的轴向负荷可破坏椎体终板，使邻近的椎间盘组织疝入椎体。大多数爆裂骨折可引起椎管侵害，骨块特别常来自上终板。进行性神经损害、进行性后凸、放射学证实的后柱不稳、椎体高度丧失大于50%伴有后凸者被认为是不稳定。骨折和凹陷的终板增加了椎间盘疝入椎体、局部畸形、治疗失败的机会。这样一来，对胸腰椎爆裂骨折通过间接复位辅以球囊扩张使终板复位就可以重建前柱和终板的稳定，从而保持矢状序列的长期稳定。微创的优势在于恢复快、疼痛轻、减少了外科手术率、由于对组织破坏少，可能更稳定。Transpedicular vertebral cancellous bone grafting for the treatment of vertebral compression fractures has been described in the published data with little success in maintaining the anterior column of the spine and was associated with a high failure rate.11-15 Transpedicular hydroxyapatite stick grafting is another technique, which is currently under investigation.16经椎弓根植骨治疗椎体压缩骨折，文献报道难以维持前柱，并有很高的失败率。近来导航下经椎弓根羟基磷灰石棒植入是另一项技术。Basic Science Studies Mermelstein et al17 showed in their cadaveric burst fracture study that vertebroplasty with calcium phosphate cement (CPC) reinforced the anterior column and reduced the stress on the pedicle-screw rod construct. In another cadaveric study18 balloon-assisted endplate reduction was used to signicantly restore vertebral height and end plate anatomy after short segmental instrumentation. A follow-up study by the same group used a detailed 3-dimensional radiography at different phases of the model, from fracture to balloon-assisted endplate reduction and cement injection. They demonstrated no collapse after removal of the balloons, maintenance of the vertebral height with cement injection, and no cement extravasation.18 Another study investigated the role of the longitudinal ligaments during balloon-assisted endplate reduction in thoracolumbar burst fractures.19 In a human cadaveric burst fracture model, the anterior and posterior bone displacement was assessed after applying short segmental xation followed by kyphoplasty. Although anterior bone and posterior bone displacement occurred with the ination of the balloons, the effect subsided after deation and did not recur with injection of the cement. The amount of displacement (1 mm) was thought to be of little clinical signicance. According to this study, an intact posterior longitudinal ligament does not appear to be necessary to prevent posterior bone displacement. They could also not conrm the importance of the posterior longitudinal ligament with reduction through ligamentotaxis.基础研究Mermelstein等研究发现，磷酸钙骨水泥可以强化爆裂骨折的前柱，减少椎弓根钉的的压力。在另一项尸体研究中，采用球囊复位终板，短节段固定，使椎体高度和终板解剖显著恢复，该研究采用三维X线对从骨折球囊扩张终板复位骨水泥注入的不同阶段进行详细观测，他们发现球囊取出后椎体不会塌陷，骨水泥注入后椎体高度得以保持，没有骨水泥渗漏。另一项研究调查了后纵韧带在胸腰椎爆裂骨折球囊辅助终板复位中的作用。在一个人类尸体爆裂骨折模型中，采用短节段固定辅以后凸成形，评估前后骨块移位。虽然球囊扩张时前后骨块发生移位，但球囊收缩时，这种作用就减小了，且椎体内注入骨水泥后，也没有再发生。其移位的程度（1mm）没有临床意义。根据这项研究，完整的后纵韧带无法阻止后方骨块的移位。他们也无法确定韧带复位技术中后纵韧带的重要性。Clinical Studies Afzal et al reported on 16 patients (age, 22-53 years) with high-energy burst fractures (12 Denis type B and 4 Denis type C burst fractures) who were followed up for 1 month clinically and radiographically.20 Patients with posterior longitudinal ligament injury were excluded. After short segment pedicle screw xation, a balloon-assisted kyphoplasty was performed with CPC. In addition, a removable plastic jacket was prescribed for 8 weeks. Cement leakage was observed in 3 patients (2 in the spinal canal, 1 in the disk space), with no clinical consequences. No posterior wall displacement was recorded. The average kyphosis angle of the segment was reduced by 10.临床研究Afzal等报道了16例（年龄，2253岁）高能量爆裂骨折病例（12例Denis B型,4例Denis C型爆裂骨折），临床与X线进行随访1个月。后纵韧带损伤者排除在外。短节段椎弓根钉固定后，采用CPC进行球囊辅助后凸成形术。可拆式塑料夹克固定8周。3例患者发生骨水泥渗漏（2例在椎管，1例在椎间隙），没有临床症状。没有发生后壁移位，平均后凸角减少10。Another investigation included 18 patients (64 15 years) with severe thoracolumbar burst and compression fractures (Figs. 2-4).21 All patients were treated with short segment percutaneous posterior instrumentation and balloon kyphoplasty with CPC within 24 hours of injury and were followed up for 22 months. Kyphosis improved from an average of 16-2. Cement leakage was observed only anterior to the vertebral body without clinical sequelae. A second study by the same group treating thoracolumbar burst fractures with calcium phosphate and an open approach for posterior spinal instrumentation showed similarly encouraging results at 24 months without major complications (Fig. 1).22 另一项研究有18例病人（6415岁），严重的胸腰椎爆裂和压缩骨折（图24）。所有的病人都在伤后24小时内采用后路经皮短节段固定CPC球囊后凸成形术，随访22个月。后凸从平均16恢复至2。骨水泥仅渗漏至椎体前方，没有后遗症。同一小组采用羟基磷灰石和开放后路固定取得了相似的效果，随访24个月，没有严重并发症发生（图1）。A prospective case series on standalone kyphoplasty with CPC in Magerl type A fractures without decit noted a decrease of pain on the visual analogue scale from 8.7 preoperatively to 3.1 postoperatively in 7 days, and 1 at the last follow-up at 30 months.23 The Roland Morris Disability score demonstrated a similar decrease in the early postoperative time period. Two anterior wall perforations by cannulas during the procedure, and 6 cement leakages were observed on postoperative computed tomography (CT) scans (5 cases into the disk space, 1 case with small leakage in the lateral portion of the spinal canal). All were without neurological or vascular consequences. Also, no long-term complications were observed at the last 30 month follow up. Twenty percent cement resorption and substitution was noted on CT scans at 1 year postoperatively. Loss of correction was 9 (0-17) from immediate postoperatively to the last follow-up at 30 months. This may relate to loss of vertebral height as the resorbable cement is remodeled. 一项单独采用CPC后凸成形治疗没有神经损害的MagerlA型骨折的病例回顾中，术后7天疼痛视觉模糊评分从术前8.7分恢复至3.1分，术后30个月恢复至1分。Roland Morris 残疾评分在术后早期也相应下降。两例前壁穿孔，6例术后CT发生骨水泥渗漏入椎间隙，1例少量渗漏至椎管侧方。所有病人没有出现神经或血管并发症。30个月随访没有长期并发症。20%在术后1年CT观察时骨水泥吸收替代，从术后即时至术后30个月的矫正丢失为9（017），这可能与可吸收骨水泥吸收后引起的高度丢失有关。Filler Choice Considerations for materials for vertebral augmentation for high-energy thoracolumbar burst fractures are different from those in osteoporotic fractures. The cement should be injectable through cannulas, easy handling, appropriately viscous, have an adequate working time (15 min), low curing temperature, adapting and lasting mechanical properties, high radioopacity, biocompatibility, bioactivity, and slow biodegradation. The optimal mechanical properties have not yet been determined for high-energy burst fractures. Stiffness and yield strength should be similar the host bone. Presently, polymethylmethacrylate (PMMA) cement is most widely used for vertebral augmentation procedures, with an extensive history of in vitro and in vivo use. It cures with an exothermic reaction, which might be desirable in painful osteoporotic vertebral fractures, but which might be detrimental to the healing potential of high-energy vertebral fractures. PMMA is nondegradable and is signicantly stronger in compression than the host bone.24-26 充填物的选择高能量胸腰椎爆裂骨折椎体增强材料与骨质疏松骨折是不同的。水泥必须可以通过管道注入，易于处理，适当的粘稠性，有足够的工作时间（15min），较低的固化温度，适当和持续的力学性质，不透X线，生物相容性，生物活性，和低降解性等。对于高能量爆裂骨折的最合适力学性质还没有定论。硬度和强度应该与宿主骨相似。目前，聚甲基丙烯酸甲酯（PMMA）水泥广泛用于椎体强化，在体内体外均有较长的应用史。固化过程会产生发热反应，这对疼痛性骨质疏松性骨折是合适的，但对高能量椎体骨折可能会损伤其愈合潜力。PMMA无法降解，且在压力强度上远高于宿主骨。In contrast, the immediate mechanical properties of CPC are closer to bone; however, the mechanical properties during the resorptive phase are important as well. There is some evidence that bone formed under the inuence of CPC has similar mechanical properties to native host bone during its resorptive phase.26,27 In most studies CPC has been used. It consists of 61% alpha tricalcium phosphate, 26% calcium-hydrogeno-phosphate, and 3% hydroxylapatite. 相对而言，CPC的力学特性更接近于骨，但在吸收阶段的力学特性也是很重要的。有证据表明，在CPC吸收期间形成的骨与自然宿主骨有相似的力学特性。CPC已用于大多数研究中。其由61%的磷酸三钙、26%磷酸氢钙、3%5。This alpha tricalcium cement is marketed as Calcibon (Biomet, Merck, Wehrheim, Germany). Mixed with liquid-topowder ratio of 0.35, a paste is obtained with a cohesion time of 1 minute, an initial setting time of 3 minutes, and a nal setting time of 7.5 minutes at 37C without an exothermic reaction. A compressive strength of 60 Mpa is obtained at 3 days.26,28 An osteoconductive potential after 6 months without cellular toxicity was shown in an animal model.26,29-31 However, CPCs are inherently brittle with inferior tensile properties compared with PMMA. Further biomechanical studies under cycling loading are needed, especially when CPC is used without posterior xation.这种三钙水泥的商品名为Calcibon(Biomet, Merck, Wehrheim, Germany),其液体与粉的比率为0.35，混合1分钟后变为糊状，在37条件下，初始固化时间为3分钟，最终固化时间为7.5分钟，不产热。3天压强达到60Mpa。在动物模型中，6个月后诱导骨形成，没有细胞毒作用。然而，CPC的本身较脆，其抗张性低于PMMA。还要做更多循环负荷下的生物力学研究，特别是CPC单独应用没有后侧固定的情况下。Another important consideration is the interaction of the cement with the intervertebral disk tissue. Because we would not only expect direct contact of cement with host bone, but also with the intervertebral disk tissue, its effects on the viability of the disk become important.32另一个要考虑的重要问题是水泥与椎间盘组织的反应。我们要想到水泥不仅与宿主骨直接接触，而且与椎间盘组织接触，其对椎间盘活力的影响变得十分重要。Indications Most reports of kyphoplasty with posterior xation have been described after a type A 3 injury with intact posterior longitudinal ligament. Oner et al33 analyzed complications of common treatment schemes of thoracolumbar fractures. He concludes that some of the complications can be predicted with magnetic resonance imaging. In the case of nonoperatively treated low-grade thoracolumbar fractures patients age and anterior columns involvement appeared to be predictive of subsequent increase of the kyphotic angle as well as persistent pain. The most common mechanism of kyphosis increase was through a progressive settling of the disk into the fractured endplate and vertebral body. In the operative group a high degree of endplate comminution (especially of the central endplate), the amount of kyphosis reduction and involvement of the posterior longitudinal ligament complex was predictive of kyphosis recurrence. However, they found no signicant correlation between pain and radiographic ndings.适应症后凸成形结合后侧固定大多数报道用于后纵韧带完整的A3型骨折。Oner等分析了一般胸腰椎骨折治疗方案的并发症，他推断有些并发症可通过MRI预见。对于一个胸腰椎骨折年纪较轻、前柱受累的非手术治疗患者，持续的疼痛意味着后凸角可能增大。大多数后凸角增大的机制在于椎间盘组织进行性疝入骨折的终板和椎体中。对于手术的患者，粉碎的终板(特别是中央终板)、后凸的角度、及后纵韧带复合体是否受累等可以推断后凸畸形是否再发生。但他们发现疼痛与放射异常之间没有显著的相关性。In fact, traditional short segment posterior xation is prone to anterior spinal column fail