可吸收球囊椎体成形术治疗胸腰椎爆裂骨折的实验研究

[目的]探讨结合短节段椎弓根螺钉系统撑开复位内固定的可吸收球囊椎体成形术治疗胸腰椎爆裂骨折的生物力学性能变化。[方法]采集6具新鲜固定湿润成人尸体胸腰椎标本，制成T11-L1，L2～4、L1～3节段标本10个，用自由落体撞击试验造成中间椎体爆裂型骨折，行APF椎弓根螺钉撑开复位，经椎弓根于伤椎椎体内置入可吸收高分子材料-DL-乳酸与ε-己内酯（70：30）的共聚物（PDLLA-CL）制作的可吸收球囊，注入自固化磷酸钙骨水泥行可吸收球囊椎体成形术。分别于骨折前、骨折撑开复位椎体成形术后，用万能材料试验机测定中间椎体在前屈、后伸、侧屈状态下应力-应变、轴向刚度变化及扭转应力下刚度的变化。[结果]伤椎经可吸收球囊椎体成形术治疗后，抗压强度均有所增加，前屈为8％，后伸15％，侧屈9．8％，其中以后伸时增加显著（P〈0．05）。治疗后的轴向刚度普遍得到提高，与骨折前相比，前屈增加11％，后伸增加8％，侧屈增加3％。治疗后椎体在扭转应力下刚度小于骨折前，但两者差异不明显（P〉0．05）。[结论]（1）结合短节段椎弓根螺钉系统撑开复位内固定的可吸收球囊椎体成形术，有助于伤椎的重建，术后脊柱的生物力学特性接近骨折前水平；（2）可吸收球囊椎体成形术治疗胸腰椎爆裂骨折，在避免骨水泥渗漏可能导致的潜在危险之前提下，从本质上恢复胸腰椎爆裂型骨折伤椎椎体结构的完整性，恢复其高度，从而恢复和维持脊柱的生理弧度，防止继发性脊柱后凸畸形变引起的迟发性腰背痛及脊髓、神经损伤，以从根本上解决单纯用经椎弓根内固定器治疗胸腰椎爆裂型骨折遗留的并发症，为临床治疗胸腰椎爆裂骨折提供了一个新的方法。     

两种植骨法对胸腰椎爆裂骨折复位后骨缺损空隙残存率及压缩刚度的影响北大核心CSCD

目的研究胸腰椎爆裂骨折两种方法植骨后伤椎椎体的植骨量、骨缺损空隙残存率及生物力学稳定性。方法取18个4～6月龄新鲜小牛脊柱腰段(L1～5)离体标本,制备L3椎体爆裂骨折模型,模拟胸腰椎爆裂骨折行伤椎撑开复位、椎弓根螺钉内固定。将18个标本随机分为3组,每组6个,A组伤椎椎体内不植骨,B组行经双侧椎弓根伤椎椎体内植骨,C组行经单侧椎管伤椎椎体内植骨。记录B、C组植骨量;将3组标本行DR片及CT观察伤椎椎体骨缺损空隙大体情况;经CT扫描后采用数格子法计算伤椎椎体骨缺损空隙残存率;应用ElectreForce-3510高精度生物材料试验机测试标本压缩刚度。结果 B、C组植骨量分别为(4.58±0.66)g和(5.72±0.78)g,比较差异有统计学意义(t=2.707,P=0.022)。DR片及CT观察示:A组标本伤椎椎体内见较大骨缺损空隙;B组伤椎椎体的"蛋壳样"空隙内可见骨粒填充,多集中于伤椎椎体后半部,椎体前部填充不足;C组伤椎椎体内较多骨粒填充,分布均匀。A、B、C组标本骨缺损空隙残存率分别为52.0%±5.5%、39.7%±2.5%、19.5%±2.5%,C组显著低于A、B组,B组显著低于A组,差异均有统计学意义(P<0.05)。前屈压缩刚度C组显著高于A、B组(P<0.05),A、B组间比较差异无统计学意义(P>0.05);后伸压缩刚度C组显著高于A组(P<0.05),但A、B组间及B、C组间差异均无统计学意义(P>0.05);左侧弯及右侧弯压缩刚度3组间比较差异均无统计学意义(P>0.05)。结论胸腰椎爆裂骨折椎弓根钉棒系统固定结合经单侧椎管伤椎椎体内植骨较经双侧椎弓根伤椎椎体内植骨植入骨量更多,更充分,术后骨缺损空隙残存率更小,对恢复脊柱前屈-压缩刚度更好。     

后路椎弓根钉结合椎体成形治疗胸腰椎爆裂骨折

目的:探讨后路椎弓根钉固定结合终板撑开钳复位终板、自固化磷酸钙骨水泥椎体成形治疗胸腰椎爆裂骨折的临床价值。方法:采用后路椎弓根螺钉内固定结合经椎弓根终板撑开钳复位中央终板、自固化磷酸钙骨水泥椎体成形治疗胸腰椎骨折爆裂患者30例(32个椎体),男22例,女8例;年龄25～71岁,平均47岁。骨折节段:T111椎,T125椎,L114椎,L28椎,L32椎,L41椎,L51椎。按Denis分型:A型4椎,B型25椎,C型1椎,D型1椎,E型1椎。通过X线片测量术前、术后及随访8个月时椎体前缘相对高、椎体成角,了解随访期间内固定失败及后凸畸形再发情况;通过CT测量术后椎体内空隙率,通过CT重建片了解术前中央终板骨折塌陷及术后复位情况。结果:所有患者随访8～15个月,平均12个月,伤椎前缘相对高度:术前40.1%,术后98.2%,术后8个月97.8%,术后较术前显著改善,而术后8个月与术后无显著性差异。伤椎椎体成角:术前18.3°,术后2.7°,术后8个月3.2°,术后较术前显著改善,而术后8个月与手术后无显著性差异;未发生内固定失败情况及后凸畸形再发;术后椎体内空隙率3.1%,中央终板骨折塌陷复位满意。结论:后路椎弓根螺钉固定结合自固化磷酸钙骨水泥椎体成形是治疗胸腰椎骨折较理想的方法,能有效防止内固定失败和椎体再发后凸畸形,同时终板撑开钳对中央终板具有良好的复位作用。     

后路胸腰椎单椎爆裂骨折经伤椎内固定的治疗

目的探讨胸腰椎单椎爆裂骨折经后路临椎椎弓根内固定连同伤椎椎弓根内固定的手术疗效。方法2009年1月至2011年12月,笔者收治36例胸腰椎单椎爆裂骨折经后路椎弓根临椎加伤椎内固定顶压撑开复位。结果36例患者均获得随访,术后后凸畸形纠正、伤椎椎体复位满意。远期伤椎椎体高度丢失不明显。获得良好结果。结论经伤椎短节段椎弓根内固定治疗胸腰椎单椎体爆裂骨折不失为基层医院首选的方法。     

经椎弓根植骨治疗胸腰椎爆裂骨折的对照研究

目的探讨经伤椎椎弓根椎体植骨在胸腰椎爆裂骨折中的作用和疗效。方法采用经伤椎椎弓根椎体植骨，GSS-Ⅱ型系统复位、内固定治疗胸腰椎爆裂骨折22例，并与前期（2004年前）及同期未行椎弓根植骨的胸腰椎爆裂骨折26例作对照研究。术前、术后及随访时行X线及CT检查，观察椎体高度及矫正Cobb角有无丢失，内固定有无断裂、松动情况发生。结果治疗组全部病例获得随访，无一例发生内固定断裂、松动，治疗组与对照组在远期椎体高度丢失率、矫正后凸Cobb角丢失度方面有显著性差异。结论胸腰椎爆裂骨折经伤椎椎弓根椎体植骨、GSS一1型内固定后，可恢复伤椎椎体高度，重建前中柱的稳定性，防止术后远期椎体高度和矫正Cobb角的再丢失以及内固定的松动、断裂。     

硫酸钙骨水泥在胸腰椎爆裂骨折椎体成形术中的生物力学性能

[目的]评价硫酸钙骨水泥(CSC)椎体成形术在胸腰椎爆裂骨折中的生物力学性能及临床应用价值.[方法]将16具新鲜小牛胸腰椎标本分为4组,A、B、C 3组制成爆裂骨折模型后分别实施CSC磷酸钙骨水泥(CPC)、聚甲基丙烯酸酯(PMMA)椎体成形术,D组为无骨折对照组.测量指标包括:爆裂骨折前、后与复位后及椎体成形术后的椎体前缘高度;达到完全填充时的3种骨水泥的注射量;生物力学检测4组标本的极限抗压强度及刚度.[结果](1)实验组12具标本均形成胸腰椎爆裂骨折模型,平均撞击能量为66.2 J;(2)CSC、CPC、PMMA的注射量分别为:4.4 ml±0.8 ml、3.7 ml±0.7 ml、4.0 ml±0.6 ml,组间无差别(P>0.05);(3)3种骨水泥均能有效充填爆裂骨折椎体复位后遗留的骨缺损,显著恢复了伤椎高度(P<0.01);(4)A、B、C、D组的极限抗压强度分别为:1 659 N±154 N、1 011 N±142 N、2 821 N±897 N及2 439 N±525 N.PMMA能够完全恢复骨折椎的抗压强度,CSC、CPC均只能部分恢复骨折椎的强度,但CSC优于CPC(P<0.01);(5)4组椎体的刚度分别为:(140±40)N/mm、(148±33)N/mm、(236±97)N/mm、(224±38)N/mm.CSC的刚度低于完整椎体68.0%,(P<0.05),但与PMMA、CPC无显著差异(P>0.05).[结论]经CSC椎体成形术的骨折椎强度优于CPC,刚度与PM-MA、CPC相当.将CSC椎体成形术作为一种辅助治疗方式用于胸腰椎爆裂骨折能满足力学要求,手术安全可行.     

后纵韧带对椎体爆裂骨折椎管内骨块复位作用的生物力学研究

目的：观察脊柱后纵韧带（PLL）的形态,力学强度及其在不同状态下对椎体爆裂骨折突入椎管骨块前推复位力。方法：取人体新鲜脊柱标本解剖观测PLL形态,并游离后测试PLL强度：取人体脊柱标本制作爆裂骨折模型,以测力探头测试脊柱不同状态下PLL对突人椎管骨块的前椎复位力,结果：PLL在胸腰段较宽,抗拉力强度平均197．7N;在撑开力（140N）作用下PLL前推复位力明显增加,撑开状态下后伸时PLL前推力与前屈时无显著性差异;PLL推力与骨块占位程度成正相关。结论：PLL的解剖及力学条件为椎管内骨块的间接复位减压提供了一定的基础,撑开力作用是PLL对骨块间接复位作用的决定性因素。在治疗胸腰椎爆裂骨折中要获得椎管内骨块的间接复位减压,应使用具有较强撑开能力的内固定装置进行纵向撑开。     

后凸成形术结合体位复位治疗创伤性胸腰椎椎体骨折的临床观察

目的：观察在体位复位辅助下后凸成形术治疗创伤性胸腰椎椎体骨折的临床疗效。方法：37例新鲜单节段胸腰椎椎体骨折患者,男28例,女9例;年龄24～79岁,平均48岁。通过体位复位及Sky扩张器撑开复位后,经双侧椎弓根穿刺充填自固化磷酸钙人工骨（CPC）。根据Denis胸腰椎骨折的分型：压缩性骨折,B型27例,C型3例,D型5例;爆裂性骨折2例,均为B型。利用体位复位,经皮穿刺,Sky椎体成形器扩张椎体,注入可降解的自固化磷酸钙人工骨。根据术前和术后侧位X线片测量椎体高度、后凸畸形角度,并计算椎体高度丢失率和后凸畸形矫正率,记录分析视觉模拟评分（VAS）及伤椎形态变化。结果：术后随访9～24个月,平均13个月。术后伤椎处疼痛均显著缓解,VAS评分改变从术前平均（7.6±2.5）分降至术后平均（1.8±1.5）分,椎体前壁高度和中间高度明显恢复,后凸畸形得到矫正。随访期间疗效满意,伤椎高度无明显丢失。结论：在严格掌握适应证、选择合适病例的前提下,采用体位复位辅助下经皮椎体后凸成形术治疗创伤性胸腰椎椎体骨折,能迅速缓解疼痛,有效恢复椎体高度和矫正后凸畸形。     

经伤椎椎弓根钉内固定系统直接复位联合cage椎间植骨融合术治疗下腰椎爆裂骨折

目的探讨下腰椎爆裂骨折后,经伤椎椎弓根内固定系统直接复位联合cage椎间植骨融合的治疗方法及临床效果。方法采用经伤椎椎弓根钉内固定系统直接复位联合应用cage椎间植骨融合术治疗下腰椎爆裂骨折26例。结果平均随访18.3个月,伤椎椎体无明显丢失,内固定牢靠、无折断、松动,cage椎间植骨融合良好。结论经伤椎椎弓根钉内固定系统直接复位联合cage椎间植骨融合术治疗下腰椎爆裂骨折,可实现三柱在三维上的同时复位,恢复伤椎高度,也可使伤椎与邻近椎体融合,增强下腰椎的稳定性,维持下腰椎的生理曲度。     

后路不同复位方式治疗胸腰椎爆裂骨折的临床疗效观察

目的探讨后路不同复位方式治疗胸腰椎爆裂骨折疗效比较。方法对55例AO分类为A型及部分B1、B2型的胸腰椎骨折患者临床资料进行回顾性分析:均采用后路手术,伤椎置钉;其中一组(A组)以单纯后方轴向撑开复位骨折椎体;另一组(B组)以伤椎椎弓根螺钉按撬拨、矫形原理恢复生理弧度及椎体高度,再适当撑开或不撑开,分别从伤椎前缘压缩比、侧位Cobb角、椎管面积比对比两组的治疗效果。结果 2组术前、术后椎体前缘压缩比、Cobb角及椎管面积比均有统计学意义(P<0.05),在椎体前缘压缩比和Cobb角恢复方面,B组明显优于A组,差异显著(P<0.05),并且无后方韧带复合结果过撑现象。结论伤椎置钉技术对胸腰爆裂椎骨折具有良好的即时复位效果,但通过伤椎螺钉撬拨复位优于单纯后方轴向撑开。     

椎体成形在胸腰椎压缩性骨折后的三维稳定性测试

目的评估在胸腰椎骨折后椎体成形术对恢复脊柱单元即刻三维稳定性的作用。方法7具新鲜胸腰段脊柱标本。测试前屈、后伸、左侧弯、右侧弯、左旋转、右旋转的中性区（neutral zone,NZ）和运动范围（range of motion,ROM）。程序：①完整状态;②骨折后状态;③椎体成形后;④3000次循环疲劳后。结果骨折后中性区和运动范围均明显增大。椎体成形后屈伸、侧弯、旋转在NZ及ROM均明显减少。疲劳后虽然有增加,但较骨折后明显减少。运动范围在椎体成形后和损伤前完整时比较无差别。结论骨水泥椎体成形在离体常规负荷下可恢复脊柱运动单元的三维稳定性。     

外固定器联合经皮椎体植骨微创治疗胸腰椎爆裂性骨折的影像学评价

目的探讨经皮外固定技术治疗胸腰椎爆裂性骨折的影像学变化结果。方法 2007年1月～2008年12月,对39例采用外固定联合经皮椎体植骨术治疗的胸腰椎爆裂性骨折患者进行临床随访观察。测量并计算术前、术后、拆外固定前及末次随访时的局部后凸角、椎体前缘高度丢失率及椎管狭窄率,并进行统计学分析,探讨该术式治疗胸腰椎爆裂性骨折的疗效。结果 39例患者平均随访37.6个月,骨折节段分布为T9～L4。神经功能按美国脊柱创伤学会（American Spinal Injury Association,ASIA）神经功能分级标准分级：D级8例,E级31例;8例D级患者于术后3周～3个月均恢复为E级,随访无神经功能损伤加重病例出现。术后的局部后凸角、椎体前缘高度及椎管狭窄率均明显改善,与术前相比差异有统计学意义（P〈0.01）;末次随访时局部后凸角及椎体前缘高度均有少量丢失,但与术前相比差异仍有统计学意义（P〈0.01）,椎管狭窄率无丢失。结论采用外固定联合经皮椎体植骨术治疗胸腰椎爆裂性骨折可获得良好的矫形效果,是一种胸腰椎骨折可靠的治疗方法。     

Short segmental pedicle screw fixation combined with percutaneous vertebroplasty in treatment of nonadjacent thoracolumbar fractures

To evaluate the short-term outcomes of short segmental pedicle screw fixation combined with per-cutaneous vertebroplasty in treatment of nonadjacent tho-racolumbar fractures. Methods: Twenty patients who suffered from nonadja-cent thoracolumbar fractures were treated by short segmental pedicle screw fixation for burst fracture and by percutane-ous vertebroplasty for compression fracture. X-rays, CT and MRI scans were conducted using the same protocol before and after surgery and during follow-up. Pre- and post-operative American Spinal Injury Association (ASIA) grades, fusion of fracture sites, visual analog scale (VAS) of back pain, and Oswestry disability index (ODI) were accessed. Results: All patients were followed up for an average period of 12 months. The sagittal profile of the thoracolum-bar spine was restored satisfactorily. No patient had neuro-logic deterioration after surgery, and 9 patients with incom-plete lesions improved postoperatively by at least one ASIA grade. The fusion rate was 100%. The average VAS of back pain was 7.6 preoperatively and 3.2 postoperatively. The average ODI was 72.5 preoperatively and 35.5 postoperatively. Conclusions: Short segmental pedicle screw fixation combined with percutaneous vertebroplasty in treatment of nonadjacent thoracolumbar fractures exhibits such advan-tages as preserving functional segment units, reliable fixation, good neurologic recovery and early mobilization and, therefore, is suitable for treating nonadjacent thora-columbar fractures.     

Short-segment pedicle instrumentation of thoracolumbar burst fractures: does transpedicular intracorporeal grafting prevent early failure?

STUDY DESIGN: A prospective, randomized study comparing two treatment methods for thoracolumbar burst fractures: short-segment instrumentation with transpedicular grafting and the same procedure without transpedicular grafting. OBJECTIVE: To evaluate the efficacy of transpedicular grafting in preventing failure of short-segment fixation for the treatment of thoracolumbar burst fractures. SUMMARY OF BACKGROUND DATA: Short-segment pedicle instrumentation for thoracolumbar burst fractures is known to fail early because of the absence of anterior support. Additional transpedicular grafting has been offered as an alternative to prevent this failure. However, there is controversy about the results of transpedicular grafting. METHODS: Twenty patients with thoracolumbar burst fractures were included in the study. The inclusion criterion was the presence of fractures through the T11-L3 vertebrae without neurologic compromise. The patients were randomized by a simple method into two groups. Group 1 patients were treated using short-segment instrumentation with transpedicular grafting (TPG) (n = 10), and Group 2 patients were treated by short-segment fixation alone (NTPG) (n = 10). Clinical (Likert's questionnaire) and radiologic (sagittal index, percentage of anterior body height compression, and local kyphosis) outcomes were analyzed. RESULTS: The two groups were similar in age, follow-up period, and severity of the deformity and fracture. The postoperative and follow-up sagittal index, percentage of anterior body height compression, and average correction loss in local kyphosis in both groups were not significantly different. The failure rate, defined as an increase of 10 degrees or more in local kyphosis and/or screw breakage, was also not significantly different (TPG = 50%, NTPG = 40%, P = 0.99). CONCLUSIONS: Short-segment transpedicular instrumentation of thoracolumbar burst fractures is associated with a high rate of failure that cannot be decreased by additional transpedicular intracorporeal grafting.     

经椎弓根椎体内植骨在胸腰椎新鲜爆裂骨折治疗中的应用

目的 :探讨经椎弓根椎体内植骨在治疗胸腰椎骨折中的意义及其疗效。方法 :采用经椎弓根椎体内植骨 ,结合椎管环形减压、短节段椎弓根螺钉系统固定治疗胸腰椎新鲜爆裂骨折 76例。术前及不同随访时间行X线和CT检查 ,测量伤椎椎体中央高度值 ,比较植骨后椎体高度的恢复程度。采用配对t检验进行统计学分析。结果 :全部患者术后平均随访 13 .2个月 ,未出现植骨操作引起的神经血管并发症 ,伤椎椎体高度恢复并维持良好。伤椎椎体中央高度值与正常值比较 ,差异无显著性意义 (P >0 .0 5 )。CT显示椎体内植骨块融合良好。结论 :胸腰椎新鲜爆裂骨折在后路椎管环形减压及内固定同时经伤椎椎弓根进行椎体内植骨 ,可恢复伤椎椎体高度 ,重建前、中柱的稳定性 ,预防术后椎体塌陷的发生。     

Percutaneous vertebroplasty for treatment of thoracolumbar spine bursting fracture

OBJECTIVE: Percutaneous vertebroplasty can be very beneficial for patients with vertebral osteoporotic compression fractures. To the best of our knowledge, however, there has been no mention in any literature regarding the use of percutaneous vertebroplasty for the treatment of spinal burst fracture. METHODS: A preliminary study was conducted on 6 patients with traumatic burst fractures of vertebrae treated with percutaneous vertebroplasty starting in June 2000. Fractures involving the anterior and middle columns of the vertebrae and the canal were mildly compressed by the retropulsed bone fragment. However, there was no obvious neurologic deficit in these patients. They initially underwent conservative treatment and thoracolumbar spinal orthosis (TLSO) brace for at least 3 months, but the intractable pain caused patients to be bedridden for prolonged periods of time and limited daily activity. As a result, the patients underwent percutaneous vertebroplasty with polymethylmethacrylate (PMMA) for treatment of spinal burst fractures. RESULTS: Six male patients (mean age: 38.2) who suffered from burst fractures of vertebrae with disabling back pain refractory to analgesic therapy and TLSO brace were treated in this study. The duration of conservation treatment period was 3.5 months to 8 months (mean: 5.2 months). There was no motility. However, 4 vertebrae (66.7%), on radiographs revealed evidence of PMMA leakage through the endplate fracture site into either the disc space or the paravertebral space, without any evident clinical symptoms. No intracanal leakage was seen, and no patient needed a secondary surgical intervention. Pain decreased from 84.3 +/- 5.4 mm at baseline to 34.7 +/- 4.4 mm at the third postoperative day, 30.2 +/- 5.8 at 3 months and 24 +/- 3.5 mm at 12 months. The reduction in pain from baseline to the 3-day and 3 month mark was statistically significant (p < 0.05). The mobility was at least 2 levels of improvement (mean improvement 2.7 points) at 12-months postoperative. CONCLUSION: In highly selective patients, percutaneous vertebroplasty can be an alternative method for the treatment of spinal burst fractures and the prevention of complications from major surgical procedures. However, this procedure still has potential risks and should be employed with extreme caution to prevent extravasation of PMMA into the spinal canal.     

Mechanical efficacy of vertebroplasty: influence of cement type, BMD, fracture severity, and disc degeneration

INTRODUCTION: Osteoporotic vertebral fractures can be treated by injecting bone cement into the damaged vertebral body. "Vertebroplasty" is becoming popular but the procedure has yet to be optimised. This study compared the ability of two different types of cement to restore the spine's mechanical properties following fracture, and it examined how the mechanical efficacy of vertebroplasty depends on bone mineral density (BMD), fracture severity, and disc degeneration. METHODS: A pair of thoracolumbar "motion-segments" (two adjacent vertebrae with intervening soft tissue) was obtained from each of 15 cadavers, aged 51-91 years. Specimens were loaded to induce vertebral fracture; then one of each pair underwent vertebroplasty with polymethylmethacrylate (PMMA) cement, the other with another composite material (Cortoss). Specimens were creep loaded for 2 h to allow consolidation. At each stage of the experiment, motion segment stiffness in bending and compression was measured, and the distribution of compressive loading on the vertebrae was investigated by pulling a miniature pressure transducer through the intervertebral disc. Pressure measurements, repeated in flexed and extended postures, indicated the intradiscal pressure (IDP) and neural arch compressive load-bearing (F(N)). BMD was measured using DXA. Fracture severity was quantified from height loss. RESULTS: Vertebral fracture reduced motion segment stiffness in bending and compression, by 31% and 43% respectively (p<0.001). IDP fell by 43-62%, depending on posture (p<0.001), whereas F(N) increased from 14% to 37% of the applied load in flexion, and from 39% to 61% in extension (p<0.001). Vertebroplasty partially reversed all these effects, and the restoration of load-sharing was usually sustained after creep-consolidation. No differences were observed between PMMA and Cortoss. Pooled results from 30 specimens showed that low BMD was associated with increased fracture severity (in terms of height loss) and with greater changes in stiffness and load-sharing following fracture. Specimens with low BMD and more severe fractures also showed the greatest mechanical changes following vertebroplasty. CONCLUSIONS: Low vertebral BMD leads to greater changes in stiffness and spinal load-sharing following fracture. Restoration of mechanical function following vertebroplasty is little influenced by cement type but may be greater in people with low BMD who suffer more severe fractures.     

经椎弓根植骨预防骨折后椎体塌陷的疗效观察

目的探讨经椎弓根椎体内植骨治疗胸腰椎骨折的疗效。方法采用植骨器械经椎弓根椎体内植骨,结合椎管减压、短节段椎弓根螺钉固定治疗胸腰椎骨折52例并获得2年以上随访。测量伤椎椎体中央高度值,比较植骨后椎体高度的恢复程度,观察植骨融合情况。采用配对t检验进行统计学分析。结果52例患者术后随访27～62个月,平均36个月。CT显示椎体内植骨融合良好,伤椎椎体中央高度值与正常值比较,差异无统计学意义（P〉0．05）。6例（12％）出现伤椎椎体塌陷,其中3例后凸成角,内固定失败,再次手术治疗。结论椎管减压及内固定同时经伤椎椎弓根进行椎体内植骨可恢复伤椎椎体高度,重建前、中柱的稳定性可预防术后远期椎体塌陷的发生。     

胸腰椎爆裂性骨折模型的快速制备

目的探讨快速制备胸腰椎爆裂性骨折模型的方法。方法取20个猪胸腰段3联体标本,上下椎体行环氧树脂包埋,中间椎体中部一侧前1/3、2/3处用直径为3.2 mm的钻头钻孔,平行对穿椎体,造成中间椎体的有限性损伤,游标卡尺测量骨折前L1椎体前缘高度,记为完整椎体的高度(HInt)。将9 kg不锈钢锤置于高0.5 m高处,沿引导杆垂直撞击标本,若L1椎体无骨折迹象则升至0.6 m的高度,若有骨折迹象则将钢锤降至0.4 m,在0.5 m的基础上以0.1 m递增或递减进行多次撞击,直至L1形成爆裂性骨折,记录撞击总能量,撞击总能量E=mgh1+mgh2+…+mghn。爆裂性骨折形成后再次测量L1椎体的前缘高度,记为HFr并对所形成的爆裂性骨折模型行影像学检查。结果骨折前椎体前缘高度为(27.405±1.453)mm,骨折后椎体前缘高度为(17.784±1.362)mm,骨折前后差异有统计学意义(P0.05)。当撞击高度为0.5 m时有4个爆裂性骨折模型形成,当累计撞击高度为0.9 m时有13个爆裂性骨折模型形成;当累计撞击高度为1.3 m时有3个爆裂性骨折模型形成。累计平均撞击高度为0.865 m;累计平均撞击能量为76.313 J。影像学显示所有标本椎体均造成典型爆裂性骨折。结论采用上下椎体包埋,中间椎体有限损伤,多次撞击实验可以制作典型胸腰椎爆裂性骨折的模型。