胸腰椎骨折的手术和非手术治疗.doc

Seminars inSPINE SURGERYOperative versus Nonoperative Treatment of Thoracolumbar Burst Fractures胸腰段爆裂性骨折的手术与非手术治疗Adam L. Shimer, MD,* and Brian W. Su, MDHigh energy injuries to the thoracolumbar (TL) region are commonly encountered and have been described since the time of Hippocrates. Despite this long history and mountains of manuscripts generated on the topic, the optimal care of TL burst fractures remains controversial. There is such great heterogeneity in study designs, inclusion criteria, and interventions used that traditional treatment guidelines require a critical re-evaluation. Many outcome studies have failed to correlate radiographic indicators such a kyphosis, loss of vertebral body height, and canal compromise to long-term clinical outcomes. Furthermore, 3 large prospective, randomized trials have demonstrated outcome equivalency of operative and nonoperative treatment for TL burst fractures without neurological compromise. Surgical intervention remains the standard of care in the setting of progressive neurological deficits, fracture-dislocations, and translational instability. Semin Spine Surg 22:38-43 2010 Elsevier Inc. All rights reserved.KEYWORDS thoracolumbar, burst, fracture, review, evidence-basedHistory历史The thoracolumbar (TL) region of the spine ranges by definition from T11 to L2 inclusively. This area is particularly susceptible to injury because it transitions from a fixed kyphotic spine to a mobile lordotic spine. In 1931, Jones1 described a pure flexion injury to the TL spine that could be anatomically reduced and adequately treated with hyperflexion and cast maintenance in that position. In 1963, approximately 30 years later, Holdsworth2 reexamined TL fractures both as a homage to Watson Jones and because of his overall dissatisfaction with clinical outcomes after treatment of these injuries. The study reported on his experience of treating more than 1000 patients and was later reprinted in JBJS in 1970 as a result of the excitement it generated from lectures he gave at the Albert duPont Center in 1969, the same year of his death. Holdsworth described the “two-column” model of TL stability emphasizing the importance of the posterior ligamentous complex (PLC), which he defined as a group of ligaments composed of the posterior facet joint, intraspinous ligament, ligament flavum, and the supraspinous ligament.3脊柱的胸腰段区域被定义为T11L2。由于处于相对固定的后凸脊柱与活动的前凸脊柱的转换区域，因此易于损伤。1931年，Jones描述了胸腰段的单纯的屈曲损伤，可以通过充分的过度屈曲实现解剖复位，并应用石膏保持复位状态。1963年，近30年后，Holdsworth一方面作为向Watson Jones致敬，另一方面也是由于对这些损伤治疗临床结果的不满意，他重新审视了胸腰段骨折。研究报道了他治疗超过1000例病人的治疗经验，随后1970年发表在JBJS杂志上。Holdsworth描述了胸腰段稳定性的“两柱”模型，强调了后侧韧带复合体的重要性，他定义后侧韧带复合体包括后侧关节面、棘间韧带、黄韧带和棘上韧带。He asserted that a “burst” fracture was from a vertical compression force where the body is “shattered from within outward” and that it was always a stable injury by definition, thereby amenable to 3 months of casting.2 Holdsworth also described a burst variant that involved PLC disruption which rendered the fracture biomechanically unstable and required surgical stabilization. In 1983, Denis4 introduced the concept of the 3-column spine which emphasized the importance of the middle column consisting of the posterior half of the body, posterior annulus, and the posterior longitudinal ligament. The importance of the middle column rather than the posterior structures as championed by Holdsworth was based on biomechanical studies that demonstrated that the posterior longitudinal ligament as well as the posterior aspect of the annulus needed to be disrupted to create instability. Denis defined a burst fracture as failure of the anterior and middle columns under compression and defined instability as a middle column injury associated with either a PLC or anterior column injury. The mechanistic classification of TL fractures by Ferguson and Allen,5 published 1 year later, described injuries according to 3 anatomic regions and eschewed Denis “column” concept as anatomically and biomechanically incorrect. They determined that disruption of the posterior elements leads to instability, similar to Holdsworths conclusion. Of note, Ferguson and Allen were the first group to describe bony retropulsion and canal compromise as a prominent feature of TL burst fractures. Magerl et al,6 in a retrospective review of 1445 fractures, were the first to relate classification to prognosis in TL injuries. The mechanistic classification is very complex and based on the direction of force; compression, distraction, or rotation.他评估“爆裂性”骨折是由于承受垂直压迫，椎体“向外侧粉碎”，为一种稳定性损伤，治疗采取石膏制动3个月。Holdsworth同时描述了合并后侧韧带复合体的爆裂性骨折，认为此类骨折存在生物力学不稳定，需要手术稳定。1983年，Denis介绍了三柱的概念，并强调了中柱的重要性。中柱的重要性大于后侧结构这一观点得到了Holdsworth的支持，他是基于生物力学研究显示，要导致不稳定，需要后纵韧带以及纤维环均发生破裂才行。Denis将爆裂性骨折定义为在压缩应力下前中柱破坏，将不稳定定义为中柱损伤合并后侧韧带复合体或者前柱损伤。1年后，Ferguson等提出胸腰段骨折机械性的分型，认为损伤划分3个解剖区域及Denis “柱”的概念在解剖学和生物力学上是不正确的。他们认为是后侧元件的破裂导致不稳定，这与Holdsworths的结论一致。Ferguson等首先提出骨块突入椎管导致占位是胸腰段爆裂性骨折的主要特征之一。Magerl等回顾了1445例骨折，首次将胸腰段损伤的进展同分类想联系。机械性的分型非常复杂，基于应力的方向，压缩、牵张或旋转。It is well known that classification systems should provide a common language for clinicians, hold prognostic implications, and direct treatment. The fundamental basis of all classifications on TL burst fractures is the assessment and/or achievement of spinal stability which White and Panjabi7 define as the “ability to limit patterns of displacement so as not to damage or irritate the spinal cord or nerve roots and, in addition, to prevent incapacitating deformity or pain due to structural changes.” James et al8 conducted a landmark human cadaveric biomechanical study examining the relative contribution of the anterior, middle, and posterior columns to spinal stability. Disruptions of the columns progressed from anterior to posterior analogous to the direction of forces generated in a TL burst fracture. They determined that the posterior, not the middle column, was the key to resistance of flexion and kyphosis which agreed with the principles of Holdsworth, and Ferguson and Allen. As such, it is now well agreed upon that integrity of the PLC in the setting of a TL burst fracture is critical to biomechanical stability and is used as a major component for dictating operative or nonoperative treatment of these injuries in the Thoracolumbar Injury Classification System (TLICS) score.9,10众所周知，分型系统应该提供有关临床、并发症、直接治疗方面的信息。胸腰段爆裂性骨折分型的主要基础是评估和/或达到脊柱稳定性，即White等定义为“限制移位以避免破坏或刺激脊髓或神经根，另外，防止由于结构改变导致的残废或疼痛”的能力。James主持的一项重要的人类尸体生物力学研究检验了前中后柱对于脊柱稳定性的关系。从前到后柱的破裂类似于产生于胸腰段爆裂性骨折的直接应力。他们确定，是后柱，而不是中柱，是预防屈曲和后凸畸形的关键，这一点复合Holdsworth和Ferguson的看法。这样，符合后侧韧带复合体的完整性在胸腰段爆裂性骨折的生物力学稳定性中是关键性，并且被用作一个主要的元素用以提示此类损伤的采用手术或非手术治疗，根据胸腰段损伤分类系统评分。Principles of Treatment治疗原则The treatment of TL burst fractures is based on two primary principles, neurological optimization and biomechanical stability. Neurological optimization includes prevention, limitation, and possible reversal of neurological compromise by eliminating neural compression through stabilization of the spinal segment. An unstable TL burst fracture carries the risk of symptomatic posttraumatic deformity, delayed mobilization, and progressive neurological deterioration.胸腰椎爆裂性骨折的治疗主要基于两个原则，神经“最优化”和生物力学稳定性。神经“最优化”包括预防、限制以及通过减压脊柱节段稳定达到神经功能逆转。不稳定性胸腰椎爆裂性骨折带来症状性脊柱后凸、卧床时间延长以及迟发性神经功能恶化的风险。Nonoperative Treatment非手术治疗Nonoperative treatment consists of pain control, preventative care (pulmonary therapy, venous thromboembolism prophylaxis), and brace immobilization. Dating back to Watson Jones, fractures secondary to flexion-compression forces are reduced and maintained by hyperextension. Traditional casting has been largely supplanted with functional bracing. Bracing options include a cruciform anterior spinal hyperextension brace, Jewett hyperextension brace, or a custom-molded polypropylene thoracolumbosacral orthosis (TLSO). Despite the increased cost of a TLSO compared with “off-the-shelf” bracing options,11 our preference is a TLSO as it has shown to have superior control in all planes,12 is easy to don and doff, and is easy to clean. Our protocol involves 24 hours per day of TLSO treatment for 3 months with routine standing lateral radiographs at 3, 6, 9, and 12 weeks to assess for progressive kyphosis. Other risks of nonoperative management which need to be closely monitored include neurological decline, skin breakdown, respiratory or intra-abdom-inal restriction, and noncompliance. It should be noted that surgical treatment does not obviate the need for bracing because many surgeons elect to brace patients postoperatively. A recent systematic review by Giele et al13 failed to demonstrate conclusive evidence to support the use of braces in TL fractures.非手术治疗包括疼痛控制、预防措施（肺功能治疗、预防静脉血栓栓塞）以及支具制动。回溯到Watson Jones，继发于屈曲-压缩应力的骨折已经减少了，而过伸伤则逐渐增多。传统的石膏已经逐渐为功能性支具所取代。这些支具包括十字形的前侧脊柱过伸支具、Jewett过伸支具或者定制的聚丙烯材料胸腰骶支具(TLSO)。尽管TLSO相对现有的支具价格高，但TLSO的各向稳定性均更好，且易于穿脱及清洗，因此，我们仍然推荐使用该支具。我们的策略包括24小时佩戴TLSO共3个月，在3, 6, 9和12周摄常规站立位片评估脊柱后凸畸形情况。非手术治疗的其他的风险包括神经功能恶化、皮肤破溃、呼吸及腹部受限以及不顺从。应该注意到手术治疗并不能代表可以不使用支具，因为很多外科医生术后仍然选择支具保护。Giele等最近的一篇系统性回顾中没有找到关于支持胸腰椎骨折使用支具的结论性的证据。Operative Treatment手术治疗Traditionally, operative techniques for the treatment of TL burst fractures have included a combination of anterior and/or posterior decompression, followed by anterior and/or posterior stabilization. Direct neural decompression can be performed anteriorly through a corpectomy followed by cage or allograft strut placement and subsequently by an anterior rod/screw or plate construct. In our experience, this should be followed by posterior short-segment fixation in the setting of a PLC injury. It is our experience that an anterior corpectomy within 48 hours after injury is associated with significantly more blood loss and morbidity.14 Therefore, it is our preference to clear retropulsed fragments through a posterior extracavitary approach or indirectly through posterior reduction of the fracture. The fracture is then stabilized posteriorly through short-segment pedicular fixation. This is followed up 48-72 hours later by a staged anterior corpectomy and grafting for anterior column support. It is our preference to use a humeral shaft or iliac crest allograft. Many alternative constructs have been well described, including anterior corpectomy and fusion,15 posterior alone instrumentation, and kyphoplasty reduction and cementation for anterior column support.16 Interestingly, Dai et al17 recently reported on a randomized controlled trial of 73 patients with TL burst fractures treated with fusion or nonfusion with pedicle screw instrumentation and followed up for 5 years. There were no significant differences in radiographic or clinical outcomes between the 2 techniques. Both operative time and blood loss were significantly less in the nonfusion group compared with the fusion group.一般来说胸腰椎爆裂性骨折的手术治疗包括前路和/或后路减压、前路和/或后路固定。可以通过椎体次全切除进行前路的神经减压，随后cage或自体骨块植骨以及前路棒/板固定。以我们的经验来看，如果同时合并后侧韧带复合体损伤，应该采用后路短节段固定。我们经验是，如果在急性损伤后48小时内进行前路椎体次全切除，将带来术中出血量明显增加以及病死率增加。因此，我们认为采用后侧入路清除占位骨块减压或通过后路间接骨折复位方式比较稳妥。骨折随后采用后路短节段椎弓根钉固定。48-72小时后，采用一期前路椎体次全切除植骨支撑。植骨宜采用肱骨干以及自体髂嵴。文献报道了多种治疗策略，包括前路椎体次全切除、单纯后路器械、椎体成型术复位、骨水泥注入加强前柱。值得注意的是，戴等最近报道对73个胸腰椎爆裂性骨折的病人采用后路椎弓根钉融合或不融合的方式，并随访5年。两组间在影像学及临床结果上没有发现明显的差别。与融合组相比，非融合组在手术时间以及出血量上明显减少。Indications for Operative Intervention手术干预的指征The absolute indication for surgical treatment of a TL burst fracture includes a progressive neurological deficit in the setting of neural element compression, a fracture-dislocation or translational instability, or progressive symptomatic kyphosis. Other factors, such as greater than 50% canal compromise, injury to the posterior column or PLC, greater than 50% loss of vertebral body height (LOVBH), greater than 30 of kyphosis, or any neurological compromise, remain controversial with lack of level 1 evidence despite their common use in reference texts. For example, the often cited criteria of greater than 50% canal compromise and 30 of kyphosis is from a retrospective study by Willen et al18 of 54 patients with T12 or L1 fractures, treated conservatively over a 26-year period. Over half of these patients were neurologically compromised at time of presentation with incomplete (n = 34) or complete (n = 13) paraparesis. Using measurements from plain radiographs, the study concluded that patients with canal compromise or anterior column compression exceeding 50% had a greater incidence of intractable back pain, neurologic involvement, and signs of instability.胸腰椎爆裂性骨折的绝对手术指征包括合并占位的进展性的神经功能障碍、骨折脱位或平移性的不稳定、进展性症状性的后凸畸形。其他指征包括大于50%得椎管占位、后柱或者后侧韧带复合体损伤、伤椎高度丢失大于50%、后凸畸形大于30或者神经压迫。以上指征目前存在争议，尽管它们广泛出现在各种文献当中。例如，Willen等回顾了采用非手术疗法治疗54例椎管占位超过50%和后凸畸形大于30 的T12或L1骨折长达26年以上的治疗结果（本文被其他作者多次引用）。其中超过一半的病例合并神经功能障碍（不全瘫34例、全瘫13例）。通过平片观察，该研究指出合并椎管占位或前柱压缩超过50%的病例发生难治性背痛、神经损伤和不稳定的风险大增。Outcome Studies结果研究Canal Compromise椎管占位Canal compromise is typically calculated as a ratio of the canal area of the injured level to the average of the canal areas of the 2 adjacent uninjured segments.19 The correlation between spinal canal compromise and neurological injury, and therefore clinical outcome is intuitively attractive yet remains unproven. Many authors have attributed neural injury to the dynamic canal encroachment that occurs at the time of injury, with the resulting retropulsed fragments in a recoiled partially reduced resting position.20-22 In his original description of 59 burst fractures, Denis stated that a direct relationship between the degree of obstruction of the canal and neurological deficit could not be established.4 This has been echoed by other investigators who have found no correlation between degree of canal compromise and neurological injury.22 Dall and Stauffer23 reported on 14 consecutive patients with T12 or L1 burst fractures, greater than 30% canal compromise, and incomplete neurological injury and also found no correlation between amount of canal compromise and neurologic recovery. Limb et al22 studied 20 patients using plain radiographs and found no statistically significant correlation between bony retropulsion on lateral radiographs and severity of neurological injury but correlated canal compromise to the injury severity score and neurological Frankel grade. In a prospective, consecutive series of 43 patients with TL burst fractures, 30 of whom were neurologically intact, Vaccaro et al demonstrated no correlation between canal cross-sectional area and neurologic compromise. The authors also found that, unlike in the cervical spine,24,25 a larger preinjury cross-sectional area did not confer neuroprotection. They did, however, find a correlation between neurological injury and a smaller sagittal-to-transverse diameter ratio, higher absolute transverse diameter, and higher injury severity score20 Similiarly, Meves and Avanzi,26 in a retrospective study of 184 patients found a similar correlation with an average midsagittal diameter loss of 52% in those with neurologic injury and 34% in those who were neuro intact. The finding that a smaller sagittal to transverse diameter ratio and higher absolute transverse diameter correlates to neurological injury implies that the morphology of the canal rather than its absolute cross-sectional area may be more significant. Hashimoto et al27 characterized canal shapes into oval, semicircle, horseshoe, and crescent and found that the crescent type (which has a large transverse and small sagittal diameter) correlated with neurological injury. Longitudinal studies of nonoperative treatment of neurologically intact TL burst fractures by Mumford et al19 and Cantor et al28 demonstrate remodeling of the canal occupying retropulsed fragment with reconstitution of the spinal canal at 1 year by 66% and 50%, respectively. In the setting of neurological injury, Willen et al18 reported that in patientswith 50% canal compromise, fragments did not “appear to resorb” and correlated with increasing low back and radiculopathy. Although it is often cited as a cause for surgical intervention when there is 50% canal compromise, better clinical and/or neurological outcomes after surgery in patients with 50% canal compromise have not been reported. On the contrary, Kim et al29 demonstrated that there was no correlation between neurological recovery and canal clearance after surgery.椎管占位一般是指伤椎椎管的横截面积与上下相邻两个脊柱节段的椎管横截面积平均数的比值。有关椎管占位与神经损伤之间相关性仍无可靠的结论。很多学者将神经损伤归因于损伤即刻椎管的动态压迫，当处于休息位置时有部分骨块可以回缩。Denis在对59例爆裂性骨折研究之后指出椎管占位的程度与神经损伤之间没有直接关系。这一观点得到了许多学者的支持。Dall和Stauffer报道了14例连续的椎管占位超过30%合并不全性损伤的T12或L1爆裂性骨折的病例，没有发现椎管占位与神经恢复之间有何必然联系。Limb通过平片研究了20例病人，没有发现骨块占位与神经损伤严重性之间有何关联，但椎管压缩同神经损伤分数以及神经Frankel分级之间存在关联。在一个前瞻性的连续的43例胸腰椎爆裂性骨折的研究中，30例神经功能完整，Vaccaro等没有发现在椎管横截面积以及神经压迫之间有何关联。作者同时发现伤前较大的椎管横断面积并不能提供更多的神经保护，这一点和颈椎不同。但他们发现神经损伤与较小的矢状位/水平位直径比值有关，横径越大，则相应的损伤严重分数越高。Meves和Avanzi回顾了184个病例，平均中央矢状位的丢失为52%，其中34%神经功能完好。较小的矢状位/水平位直径比以及较高的横径与神经损伤之间的关联提示椎管的形态可能较之横截面积更为重要。Hashimoto等将椎管的形状分为椭圆形、半圆形、马蹄形、新月形，并发现新月形（横径较大，矢状径较小）与神经损伤之间存在关联。Mumford等和Cantor等所作的纵向调查了神经功能完整的胸腰段爆裂性骨折的病人采用非手术治疗的情况后发现1年后椎管占位校调分别为66%和50%。对于神经损伤的病人，Willen等报道椎管占位大于50%、后凸骨块未显示吸收与背痛以及神经根病有关。尽管椎管占位大于50%常常作为手术指征被引用，但并没有此类病人治疗后去的更好的临床和/或神经功能结果的报道。相反，Kim等指出，神经功能恢复与椎管占位清除之间没有相关性。In summary, a crescent-shaped canal with a large transverse and small sagittal diameter rather than an absolute reduction in cross-sectional area may correlate with neurological injury. In the absence of a neurological deficit, canal compromise should not be considered a factor supporting surgical intervention. In the setting of a neurological deficit, 50% canal compromise may lead to increased back pain and radiculopathy with nonoperative treatment. However, there are no studies that demonstrate improved outcomes in patients with 50% canal compromise, who undergo surgical decompression.总之，椎管为新月形合并较小的矢状位/水平位直径比较之横截面积，与神经损伤之间更有相关性。对于没有神经损伤的病例，椎管占位不应视为手术干预的指征。对于超过50%的椎管占位的神经损伤的病例，采用非手术治疗可能增加背痛和神经根病的可能。但是，也没有确切的研究证实对此类病人采用手术干预能改善功能结果。Loss of Vertebral Body Height椎体高度丢失LOVBH is described by Willen et al18 as the ratio of anterior height of the fractured body to th