患椎间短椎弓根螺钉在单节段腰骶椎结核稳定性重建中的临床研究

目的证明后路患椎间短椎弓根螺钉固定治疗单节段腰骶椎结核的可行性,并探讨其适应证及疗效。方法 204例诊断明确、脊柱后凸畸形35°,符合纳入标准的单节段腰、骶椎结核患者,随机分为2组,均先进行后路矫形、内固定手术,同期或二期进行前路彻底病灶清除、椎体间自体髂骨支撑植骨融合术。其中短钉组104例,选用长20~35 mm的短椎弓根钉置于患椎椎弓根。如1个患椎剩余骨质1/3,而另1个患椎剩余骨质1/3,则行短钉、常规螺钉固定。长钉组:常规椎弓根螺钉置于患椎相邻的正常椎骨中,固定范围跨越患椎上、下各1个正常间隙。所有患者均采用四联化疗方案。结果 2组患者平均随访62.1个月。术后均无严重并发症发生,末次随访时,所有患者均治愈,无内固定松动及断裂现象。植骨平均愈合时间,短钉组4.3个月,长钉组4.6个月,Cobb角矫正度及丢失率2组分别为13.26°±3.76°,6.22%和16.35°±2.63°,5.24%,2组比较差异无统计学意义(P0.05),组内术前术后比较差异有统计学意义(P0.05)。血沉与C反应蛋白的术前术后差异无统计学意义。2组患者术后2年生活、工作基本恢复正常。短钉组患者术后功能恢复较长钉组好。结论腰、骶椎结核后路患椎间短椎弓根钉固定、前路病灶彻底清除术具有仅融合、固定病变节段,保留相邻正常的脊柱运动单元功能,术后脊柱功能恢复好等优点,具有很高的临床应用价值。     

脊柱骨折经伤椎椎弓根置钉附加横连短节段固定的稳定性测试

目的:探讨脊柱骨折经伤椎椎弓根置钉附加横连短节段钉棒固定的稳定性.方法:5具新鲜冰冻小牛腰椎标本(L1～L5)制备成L3椎体爆裂骨折模型,依次进行单纯经伤椎和上下相邻椎体椎弓根置钉短节段6钉固定(单纯经伤椎6钉固定组)和附加横连经伤椎和上下相邻椎体椎弓根置钉短节段6钉固定(附加横连经伤椎6钉固定组),测试L2～L4损伤前(对照组)、损伤后(骨折组)及单纯经伤椎6钉固定组和附加横连经伤椎6钉固定组的三维6个方向的运动范围(ROM),比较各组间的差异.结果:L3椎体爆裂骨折后L2～L4各方向的ROM明显增加,与损伤前比较均有显著性差异(P<0.05);单纯经伤椎6钉固定组与附加横连接经伤椎6钉固定组各方向的ROM均明显减小,与骨折组相比均有显著性差异(P<0.05),在前屈、后伸、侧弯运动方向的ROM小于对照组,差异有显著性(P<0.05),旋转方向上大于对照组(P<0.05).两种固定方式在前屈、后伸、侧弯方向上的ROM无显著性差异(P>0.05),附加横连经伤椎6钉固定组较单纯经伤椎6钉固定组在旋转方向上的ROM小,差异有显著性(P<0.05).结论:经伤椎椎弓根置钉短节段钉棒固定可提高骨折模型各个运动方向上的生物力学稳定性,附加横连经伤椎6钉固定技术较单纯经伤椎6钉固定技术在轴向旋转运动方向上可提供更强的力学稳定性.     

后路短节段固定结合伤椎固定经椎弓根植骨治疗胸腰段骨折

[目的]探讨后路短节段结合伤椎椎弓根钉固定加伤椎经椎弓根植骨治疗胸腰段脊柱骨折的临床疗效。[方法]对本院2003~2007年收治的胸腰段骨折治疗进行回顾,总共随访到96例病例。28例采用单纯后路短节段椎弓根螺钉复位固定,68例患者采用短节段固定结合单侧伤椎螺钉固定结合经椎弓根植骨,其中38例植骨材料为人工骨,30例为自体髂骨植骨。按照美国脊柱创伤研究组提出的胸腰椎损伤严重性评分标准(thoraco lumbar injury severityscore,TLISS)分别对各组病例进行评分,术前、术后以及随访期间正侧位X线片,测量伤椎椎体前后缘高度,胸腰段后凸Cobb′s角,前后椎体高度比,应用SPSS 11.0进行统计学分析。[结果]术后平均随访16.8个月(12~20个月),所有骨折复位效果满意。单纯后路短节段固定比经椎弓根植骨结合后路短节段固定组高度丢失多,术后Cobb′s角的矫正能力差,应用人工骨与自体骨植骨组间无明显差异。[结论]经椎弓根植骨结合后路短节段固定加伤椎固定重建了椎体的高度,增加了脊柱前柱稳定性,可有效的防止内固定失败和矫正度丢失,是一种治疗胸腰段骨折的有效方法。     

后路单节段内固定结合椎体间支撑植骨治疗腰椎滑脱症

目的探讨经后路单节段内固定结合椎体间支撑植骨治疗腰椎滑脱症的临床疗效。方法对46例腰椎滑脱症患者进行经后路减压、单节段椎弓根螺钉内固定复位、椎体间植骨融合,并进行定期随诊和影像学检查观察。结果经平均24个月的随访,优良率91.3%,固定节段滑脱无复发,植骨椎间隙全部融合,无断钉断棒发生。结论采用后路单节段椎弓根螺钉内固定结合椎体间支撑植骨治疗腰椎滑脱症固定节段短,临床效果可靠满意。     

短节段或单节段内固定结合经椎弓根伤椎植骨对胸腰椎骨折愈合的疗效分析

目的 探讨采用短节段或单节段内固定结合经椎弓根伤椎植骨对胸腰椎骨折愈合的疗效.方法 对34例胸腰椎骨折,应用经伤椎椎弓根椎体内植骨,结合短节段或单节段椎弓根钉棒系统复位固定.结果 术后随访12～26个月,后凸Cobb角由术前的平均20.7°恢复至术后平均3.7°.椎体前缘高度由术前的平均55.3％,恢复至术后平均86.6％.伤椎复位效果好,无明显相邻椎间隙过度撑开.结论 经伤椎椎弓根椎体内植骨,结合椎弓根钉棒系统复位固定治疗胸腰椎骨折,重建了脊柱前中柱的力学结构,获得了稳定性,同时获得有效的椎间盘高度,容纳复位后的髓核,减少伤椎上终板的塌陷,可明显减少内固定断裂、术后Cobb角丢失等并发症.     

伤椎置钉单节段固定植骨融合治疗胸腰段脊柱骨折

目的总结伤椎椎弓根螺钉单节段固定植骨融合在胸腰段脊柱骨折中的治疗效果。方法回顾2006年4月至2009年11月我科治疗的31例胸腰段脊柱骨折患者,其中男21例,女10例,年龄22～49岁,平均34．7岁。对其在伤椎及上位椎行短节段椎弓根螺钉内固定,椎间植骨或置椎间融合器。结果本组随访6～24个月,术后2周可下床锻炼,术后伤椎高度及脊柱Cobb角均有较大的恢复。结论伤椎椎弓根螺钉单节段固定植骨融合治疗胸腰段脊柱骨折创伤小,能较大程度的恢复骨折椎的高度及脊柱Cobb角,为脊柱生物力学重建和功能恢复提供了一个坚强而稳固的基础。     

经皮短节段椎弓根钉内固定联合伤椎植骨治疗无神经损伤胸腰椎骨折

目的探讨经皮短节段椎弓根钉内固定联合伤椎植骨治疗无神经损伤胸腰椎骨折的临床疗效,并分析伤椎植骨与否对术后远期疗效的影响。方法纳入自2014-01—2016-09诊治的63例无神经损伤胸腰椎骨折,均采用后路经皮短节段椎弓根钉内固定手术治疗,其中35例行伤椎植骨(植骨组),28例未植骨(未植骨组)。结果 63例均获得随访,植骨组随访时间平均18(15~28)个月,未植骨组随访时间平均18(15~30)个月。于术后12~24个月取出内固定物,继续随访3个月复查X线片或CT片。植骨组与未植骨组术后即刻、取出内固定前的伤椎前缘高度比值、后凸Cobb角差异无统计学意义(P0.05);植骨组取出内固定后3个月伤椎前缘高度比值及后凸Cobb角优于未植骨组,差异有统计学意义(P 0.05)。结论经皮短节段椎弓根钉内固定联合伤椎植骨治疗无神经损伤胸腰椎骨折可实现充分骨性愈合,在脊柱前中柱重新建立稳定性并再次形成支撑力,防止椎体高度与后凸畸形矫正丢失。     

短节段椎弓根螺钉内固定结合伤椎植骨植钉术在胸腰椎骨折的应用

目的：比较短节段椎弓根螺钉内固定结合伤椎植骨植钉术与跨节段椎弓根螺钉内固定术治疗胸腰椎爆裂或压缩骨折的临床疗效。方法将46例胸腰椎爆裂或压缩骨折患者随机分为2组,分别使用短节段椎弓根螺钉内固定结合伤椎植骨植钉术和跨节段椎弓根螺钉内固定结合伤椎植骨术治疗。比较两组手术时间、术中出血量、术后Cobb角、伤椎前缘高度压缩率、椎间隙高度丢失、神经功能恢复（Frankel分级）、JOA评分及VAS评分。结果两组患者手术时间和术中出血量比较,差异均无统计学意义（P〉0.05）。术后12个月神经功能Frankel分级差异无统计学意义。术后各时间点观察组、对照组Cobb角、各椎间隙高度、VAS评分及JOA评分比较差异无统计学意义（P〉0.05）。结论短节段椎弓根螺钉内固定结合伤椎植骨植钉术治疗胸腰椎爆裂或压缩骨折能有效恢复并维持伤椎高度,但不能有效地防止相邻节段的退变和后凸畸形矫正度的丢失。     

椎弓根钉单节段固定术治疗胸腰椎不稳定骨折

目的探讨后路椎弓根钉单节段固定术治疗胸腰椎不稳定骨折的临床效果。方法应用经椎弓根螺钉内固定系统单节段固定术治疗胸腰椎不稳定骨折6例,进行后路减压、植骨融合,比较神经功能及骨折愈合情况。结果全部病例获得随访,神经功能按Frankel分级,有1～3级的恢复,全部骨折均顺利愈合,椎体高度无再丢失。结论椎弓根钉单节段内固定术治疗胸腰椎不稳定骨折,可有效重建脊柱稳定性,脊柱融合率高,临床效果满意。     

后路短节段椎弓根钉内固定治疗胸腰椎骨折的进展

胸腰段骨折约占脊柱骨折的1/2.相当一部分患者需手术治疗,后路椎弓根螺钉内固定术是目前常用手术方式之一.椎弓根螺钉的应用,使脊柱骨折治疗发生了很大的飞跃,与以椎板或横突为固定点的骨钩相比,其具有力学强度大,稳定性高,融合效果好等优点.从微创理念讲,现已广泛开展的后路短节段椎弓根钉内固定术（short segmentpedicle instrumentation SSPI）尽管较长节段固定优越,但仍存在某些不足.有鉴于此,为尽可能克服上述不足,有学者开展了后路单节段椎弓根钉固定术,即将两对椎弓根钉分别固定于骨折椎及其相邻的正常椎体中,并用于临床,取得了较满意的治疗效果.     

胸腰椎爆裂骨折三种后路内固定方法的稳定性生物力学研究

[目的]比较长节段固定术、短节段固定术和短节段结合椎体成形固定术治疗胸腰椎爆裂骨折的稳定性。[方法]收集6具新鲜尸体的脊柱(T9～L5)标本,对每一具标本依次按完整状态、骨折状态、长节段固定、短节段固定和短节段结合椎体成形的顺序进行测试,计算其在屈曲、背伸、左右侧弯和左右旋转6个方向的运动范围,比较各组间差异。[结果]骨折后脊柱在6个方向上的运动范围均增加(P<0.05);各内固定组的运动范围均小于完整组(P<0.05);长节段固定和短节段结合椎体成形固定的运动范围小于单纯短节段固定组(P<0.05);短节段结合椎体成形固定在屈曲和左右侧屈方向上的运动范围与长节段固定无差别(P>0.05),而在背伸和左右旋转方向上的运动范围短节段结合椎体成形固定则大于长节段固定(P<0.05)。[结论]通过延长固定节段与联合椎体成形均能够增加短节段固定的稳定性,在屈曲和左右侧屈方向上短节段联合椎体成形已经能够达到长节段固定所能够达到的稳定性。     

全脊椎切除术后三种不同重建方法的稳定性比较

目的：评价全脊椎切除术后应用三种不同重建方式对脊柱稳定性的影响。方法：选用6具新鲜尸体T9～L3脊柱标本，建立T12全脊椎切除模型．进行三种不同的前后方重建：（1）前方人工椎体＋后方椎弓根螺钉固定；（2）前方人工椎体、钢板＋后方椎弓根螺钉固定；（3）前方骨水泥-螺钉复合体＋后方椎弓根螺钉固定。采用非损伤性加载对完整标本和三种重建方式下的每个脊柱标本的稳定性进行测试。结果：三种方法重建术后在4N载荷下T11～Ll各运动方向的平均运动范围均较完整标本小（P〈0．001），三种重建方式之间无统计学差异（P〉0．05）。结论：全脊椎切除术后三种重建方式均可以重建脊柱的稳定性。     

椎弓根内固定系统生物力学实验研究

取20具成人尸体腰段脊柱,模拟最严重前中柱损伤模型,通过测定加载方向应变和位移或角度值,比较短节段Roy—Camille、Steffee、Dick、C—D和TPRF5种椎弓根内固定系统在轴向压缩、侧弯、前屈和扭转试验的生物力学稳定性。实验结果表明:器械的稳定程度与椎弓根螺钉直径、螺钉固定装置等结构密切相关。本实验条件下,以TPRF的稳定性最好,但各种器械均不能完全恢复正常脊柱的稳定性。     

前路腰椎椎间融合术即刻稳定性的生物力学研究

目的 评价应用聚醚醚酮(poly-ether-ether-ketone,PEEK)椎间融合器行前路腰椎椎间融合的即刻生物力学稳定性.方法 采用6具成人尸体腰椎标本,均来源于男性,X线榆查排除腰椎疾患和明显退行性改变,双能X线骨密度检查证实所有标本骨密度均处于正常范围.截取L4～S2节段腰椎,用自凝型聚甲基丙烯酸甲酯将标本两端固定在夹具内.沿腰椎轴线加载500N的预负荷后,分别在生物力学试验机上检测以下三种状态的前屈、后伸及侧屈各方向活动的即刻稳定性:完整腰椎标本,L5S1椎间盘切除、PEEK椎间融合器植入,辅以后路椎弓根螺钉系统固定.结果 L5S1椎间单纯椎间融合器植入后前屈、后伸、左侧屈方向的活动范围较完整腰椎标本分别减少76.9%、66.6%与81.1%;辅以后路惟弓根螺钉系统固定后,前屈、后伸、左侧屈方向的活动范围较完整腰椎标本分别减少93.9%、90%与86.6%.完整腰椎标本的空白对照组L4,5椎间前屈、后伸与左侧屈活动度分别为4.16°±0.33°、4.02°±0.30°、3.48°±0.34.;L5S1单纯椎间融合器组则分别为5.82°±0.36°、5.38°±0.30°、4.96°±0.29°;L5S1椎间融合器辅助椎弓根螺钉固定组则分别为4.82°±0.26°、5.76°±0.31°、3.98°±0.29°.L5S1椎间单纯椎间融合器植入及附加椎弓根螺钉崮定后,L4,5椎间相对活动度显著增加,各组间差异有统计学意义(P=0.000).结论 单纯应用PEEK椎间融合器的前路腰椎椎间融合术即刻稳定性优于完整腰椎标本.辅以后路椎弓根螺钉系统固定后融合节段稳定性得到显著增强.     

In vitro biomechanical comparison of an anterior and anterolateral lumbar plate with posterior fixation following single-level anterior lumbar interbody fusion

OBJECT: Anterior lumbar interbody fusion (ALIF) is often supplemented with instrumentation to increase stability in the spine. If anterior plate fixation provided the same stability as posterior pedicle screw fixation (PSF), then a second approach and its associated morbidity could be avoided. METHODS: Seven human cadaveric L4-5 spinal segments were tested under three conditions: ALIF with an anterior plate, ALIF with an anterolateral plate, and ALIF supplemented by PSF. Range of motion (ROM) was calculated for flexion/extension, lateral bending, and axial torsion and compared among the three configurations. RESULTS: There were no significant differences in ROM during flexion/extension, lateral bending, or axial torsion among any of the three instrumentation configurations. CONCLUSIONS: The addition of an anterior plate or posterior PS/rod instrumentation following ALIF provides substantially equivalent biomechanical stability. Additionally, the position of the plate system, either anterior or anterolateral, does not significantly affect the stability gained.     

Pedicle screw fixation with translaminar facet joint screws for the treatment of thoracolumbar fracture

Objective:To evaluate the efficacy of Cotrel-Dubeusset (CD) instrumentation combined with translaminar facet joint screw ( TLS ) in the treatment of thoracolumbar fracture. Methods: A total of six L2-L4 spines were used to establish unstable fracture model with three-dimensional range of motion ( ROM ) of the spines measured. Fixation with CD and fixation with CD combined with translaminar facet joint screw were achieved to compare their stability. Thirty cases of thoracolumbar fracture, in whom the anterior edge of vertebral body was compressed to 59% and the posterior edge compressed to 88%, were treated by pedicle screw fixation combined with TLS. Among them, 19 received posterolateral or anterior-posterior bone grafting Results- There was significant difference in ROM between the two techniques except that in extension. In Group CD TLS, ROM was 5.38% lower, lateral bending 4.91% lower and axial rotation 11.85 % lower than those in Group CD respectively. In the clinical group, the average anterior edge restored to 97 % and posterior edge to 98%. The duration of follow-up was 5-24 months (mean, 10 months). The rate of correction loss on the anterior edge was 4.5%. Among the 19 cases of bone grafting, all of them achieved bony fusion (mean fusion time, 4.3 month) with a correction loss rate of 3.4%. Conclusions:In the treatment of thoracolumbar fracture, pedicle screw fixation combined with TLS can strengthen the stability of pedicle screws, especially antirotation stability and enhance fusion rate and reduce correction loss.     

Biomechanical comparison of a novel percutaneous transfacet device and a traditional posterior system for single level fusion

Posterior spinal fusions are indicated for a variety of spinal disorders. Transfacet fixation minimizes soft tissue disruption and preserves the adjacent facet joint. This technique is uncommon due to concerns with biomechanical stability and proper implant placement. For these reasons, a length adjustable implant may obviate the clinical concerns but necessitates biomechanical study. This study evaluated the in vitro biomechanical stability between a novel transfacet fixation device compared with standard pedicle screws during cyclic physiologic loading in a human cadaveric model. Cadaveric L4-L5 lumbar motion segments from 16 human spines were tested in cyclic flexion/extension, lateral bending, and torsion after insertion of either transfacet fixation devices or 5.5 mm pedicle screw instrumentation. A load cell was used to measure the compressive forces on the anterior column during testing. Motion segment stiffness and anterior column compression were analyzed with a 1-way analysis of variance (P<0.05). The transfacet device demonstrated a statistically similar stiffness when compared with the pedicle screw system for each test direction. For anterior column loading during physiologic testing, there were no biomechanical differences between stabilization systems. Percutaneous transfacet fixation is an attractive surgical option for single-level spinal fusions. A biomechanical evaluation of a novel device for this application demonstrated similar stability to a pedicle screw system. The length adjustability of the device may alleviate concerns for precise device placement and the biomechanical stability may produce similar rates and quality of posterior spinal fusions.     

A comparative biomechanical study of spinal fixation using the combination spinal rod-plate and transpedicular screw fixation system

A biomechanical study was performed comparing the stiffness and stability of the three-level combination spinal rod-plate and transpedicular screw (CSRP-TPS) fixation system with those of three anterior stabilization constructs that spanned three vertebral levels: iliac strut grafting, polymethylmethacrylate and anterior Harrington rod instrumentation (technique of Siegal et al.), and the Kaneda anterior device. The CSRP-TPS fixation system was also compared with five posterior instrumentation systems that spanned five vertebral levels: Harrington distraction rod instrumentation, segmentally wired Luque rectangular instrumentation, Cotrel-Dubousset transpedicular instrumentation. Steffee transpedicular screws and plates, and R. Roy-Camille plates under conditions of single-level instability. The relative stability of each instrumentation system was compared by mounting the fixation systems on calf spine segments containing five motion segments destabilized by complete L3 anterior corpectomies and L2-L3 and L3-L4 anterior diskectomies to simulate the two-column instability found clinically in spine fractures. Mechanical nondestructive cyclical testing in rotation, axial compression, and flexion was performed on 12 spines. All biomechanical tests were performed on a biaxial servo-controlled MTS 858 Bionix hydraulic materials testing device with a biaxial load cell. Intervertebral displacements between L2 and L4 were continuously recorded utilizing an extensometer with the knife edges placed directly adjacent to the L3 corpectomy defect during testing. This biomechanical study showed that CSRP-TPS instrumentation spanning three vertebral levels could restore the torsional, compressive, and flexural rigidity of the destabilized calf spines to that of the intact calf spines and provided more in vitro stability than either the traditional five-level Harrington distraction rod or the segmentally wired Luque rectangular instrumentation. The greatest torsional rigidity occurred with the five-level Cotrel-Dubousset instrumentation, the five-level Steffee plate and screw system, and the three-level Kaneda anterior device. In axial compression and flexural testing, the three-level CSRP-TPS system provided fixation comparable with the five-level Cotrel-Dubousset instrumentation, the five-level Steffee transpedicular screw and plate system, the five-level R. Roy-Camille plate and screw system, and the three-level Kaneda anterior device. Satisfactory levels of rigidity can be restored by three-level CSRP-TPS instrumentation under conditions of single-level instability in unstable thoracolumbar and lumbar spine fractures.     

The stability of reconstruction methods after thoracolumbar total spondylectomy. An in vitro investigation.

STUDY DESIGN: After total spondylectomy, five types of spinal reconstruction techniques were compared biomechanically. OBJECTIVES: To evaluate the stability provided by five reconstruction methods after total spondylectomy. SUMMARY OF BACKGROUND DATA: Total spondylectomy presents a worst-case scenario for spinal reconstruction. However, few investigators have biomechanically investigated spinal reconstruction stability after total spondylectomy. METHODS: Eight human cadaveric spines (T11-L5) were used. After intact analysis, a total spondylectomy was performed at L2 and reconstructed using Harms titanium mesh (Depuy-Motech, Warsaw, IN) as an anterior strut. Anterior, posterior, or circumferential instrumentation techniques were then performed using the Kaneda SR and ISOLA pedicle screw systems (AcroMed Corp., Cleveland, OH) as follows: 1) anterior instrumentation at L1-L3 with multisegmental posterior instrumentation at T12-L4 (AMP), 2) anterior instrumentation at L1-L3 with short posterior instrumentation at L1-L3 (ASP), 3) anterior instrumentation at L1-L3 (A), 4) multilevel posterior instrumentation at T12-L4 (MP), and 5) short posterior instrumentation at L1-L3 (SP). Nondestructive biomechanical testing was performed under axial compression, flexion-extension, and lateral bending loading modes. RESULTS: Only circumferential instrumentation techniques (AMP, ASP) exhibited higher stiffness than the intact spine in all loading modes (P < 0.05). Short circumferential fixation provided more stability than did multilevel posterior instrumentation (P < 0.05). Multilevel posterior fixation provided more stiffness than did short posterior and anterior instrumentation alone (P < 0.05). CONCLUSIONS: Only circumferential fixation techniques provide more stability than the intact spine in all testing modes. Short circumferential instrumentation provides more stability than multilevel posterior instrumentation alone and requires fewer levels of spinal fusion.     

Biomechanical comparison of two-level cervical locking posterior screw/rod and hook/rod techniques.

BACKGROUND CONTEXT: Locking posterior instrumentation in the cervical spine can be attached using 1) pedicle screws, 2) lateral mass screws, or 3) laminar hooks. This order of options is in order of decreasing technical difficulty and decreasing depth of fixation, and is thought to be in order of decreasing stability. PURPOSE: We sought to determine whether substantially different biomechanical stability can be achieved in a two-level construct using pedicle screws, lateral mass screws, or laminar hooks. Secondarily, we sought to quantify the differential and additional stability provided by an anterior plate. STUDY DESIGN: In vitro biomechanical flexibility experiment comparing three different posterior constructs for stabilizing the cervical spine after three-column injury. METHODS: Twenty-one human cadaveric cervical spines were divided into three groups. Group 1 received lateral mass screws at C5 and C6 and pedicle screws at C7; Group 2 received lateral mass screws at C5 and C6 and laminar hooks at C7; Group 3 received pedicle screws at C5, C6, and C7. Specimens were nondestructively tested intact, after a three-column two-level injury, after posterior C5-C7 rod fixation, after two-level discectomy and anterior plating, and after removing posterior fixation. Angular motion was recorded during flexion, extension, lateral bending, and axial rotation. Posterior hardware was subsequently failed by dorsal loading. RESULTS: Laminar hooks performed well in resisting flexion and extension but were less effective in resisting lateral bending and axial rotation, allowing greater range of motion (ROM) than screw constructs and allowing a significantly greater percentage of the two-level ROM to occur across the hook level than the screw level (p<.03). Adding an anterior plate significantly improved stability in all three groups. With combined hardware, Group 3 resisted axial rotation significantly worse than the other groups. Posterior instrumentation resisted lateral bending significantly better than anterior plating in all groups (p<.04) and resisted flexion and axial rotation significantly better than anterior plating in most cases. Standard deviation of the ROM was greater with anterior than with posterior fixation. There was no significant difference among groups in resistance to failure (p=.74). CONCLUSIONS: Individual pedicle screws are known to outperform lateral mass screws in terms of pullout resistance, but they offered no apparent advantage in terms of construct stability or failure of whole constructs. Larger standard deviations in anterior fixation imply more variability in the quality of fixation. In most loading modes, laminar hooks provided similar stability to lateral mass screws or pedicle screws; caudal laminar hooks are therefore an acceptable alternative posteriorly. Posterior two-level fixation is less variable and slightly more stable than anterior fixation. Combined instrumentation is significantly more stable than either anterior or posterior alone.