椎弓根螺钉的不同结构特点对螺钉电阻的影响

目的:研究椎弓根螺钉的不同结构特点(实心与空心螺钉、直径)对螺钉电阻的影响,进而探讨其对刺激肌电监测椎弓根螺钉置入准确性的可能影响.方法:选择临床常用的两个厂家(强生和美敦力公司)的12枚椎弓根螺钉,每个厂家各6枚,强生公司实心与空心螺钉的直径均为5.0mm、6.0mm和7.0mm;美敦力公司实心与空心螺钉的直径均为4.5mm、5.5mm和6.5mm.用万用电表测量通过椎弓根螺钉的电流,用电位差计测量螺钉杆上间隔20mm节段的电位差,通过欧姆定律计算椎弓根螺钉的电阻值.结果:美敦力公司的4.5mm实心与空心椎弓根螺钉电阻分别为(0.142±0.003)Ω和(0.398±0.002)Ω,5.5mm实心与空心椎弓根螺钉电阻分别为(0.110±0.007)Ω和(0.347±0.003)Ω,6.5mm实心与空心椎弓根螺钉电阻分别为(0.086±0.002)Ω和(0.290±0.003)Ω.强生公司的5.0mm实心与空心椎弓根螺钉电阻分别为(0.149±0.001)Ω和(0.291±0.001)Ω,6.0mm实心与空心椎弓根螺钉电阻分别为(0.123±0.004)Ω和(0.237±0.001)Ω,7.0mm实心与空心椎弓根螺钉电阻分别为(0.095±0.001)Ω和(0.148±0.001)Ω.相同直径的空心椎弓根螺钉较实心椎弓根螺钉具有较大的电阻,差异有统计学意义(P＜0.05).无论实心椎弓根螺钉或空心椎弓根螺钉,随着直径的增大,椎弓根螺钉的电阻值逐渐减小,差异有统计学意义(P＜0.05).结论:长度与直径相同的空心椎弓根螺钉较实心螺钉具有较大的电阻,长度相同的实心或空心小直径椎弓根螺钉具有较大的电阻,应用刺激肌电监测椎弓根螺钉置入时要注意其带来的影响.     

经皮椎弓根螺钉内固定治疗胸腰椎骨折疗效观察

目的探讨经皮椎弓根螺钉内固定手术治疗胸腰椎骨折的效果。方法将42例胸腰椎骨折患者随机分为开放椎弓根螺钉内固定组(开放组,21例)和经皮椎弓根螺钉内固定组(经皮组,21例)。对术中、术后反映手术创伤的指标进行监测,观察术前、术后1年椎体前缘高度和伤椎Cobb角,并进行比较分析。结果经皮组手术时间、术中出血量、术后引流量、切口长度、住院时间及带支具离床时间均少于开放组(P<0.05),经皮组内固定破坏、腰背部疼痛的程度和发生率均低于开放组(P<0.05);两组术后伤椎椎体前缘高度、Cobb角与术前比较差异均有统计学意义(P<0.05),经皮组伤椎椎体恢复较开放组好。结论微创经皮置入椎弓根钉固定技术治疗胸腰椎骨折并发症少,功能恢复较开放椎弓根螺钉内固定好。     

经皮微创椎弓根螺钉内固定治疗胸腰椎压缩性骨折的临床疗效研究

目的：探讨经皮微创椎弓根螺钉内固定治疗胸腰椎骨折的临床疗效。方法：回顾性研究自2012年1月至2015年6月收治胸腰椎骨折且无脊髓及神经损伤患者22例,均为单节段椎体骨折,采用经皮微创椎弓根螺钉内固定。同期对照组的22例患者行常规后路切开复位内固定术。对两组患者的临床及影像学指标、术后疼痛评分行统计学分析。结果：所有患者均未出现术后感染、内固定松动断裂、脊髓神经损伤等并发症。两组患者临床指标中术中出血量、住院天数存在统计学差异(P<0.05),而手术时间无明显统计学差异。影像学指标中术后矢状位后凸Cobb角均较术前有明显改善,但组间比较无明显统计学差异。椎体前缘影像学高度术后1月存在统计学差异,但术后6月、12月无明显统计学差异。术后疼痛评分经皮微创椎弓根螺钉内固定组术后1月疼痛较常规后路切开复位内固定组明显减轻,差异有统计学意义(P<0.05),但术后6月、12月无明显统计学差异。结论：经皮微创椎弓根螺钉内固定技术具有损伤小、出血少、术后疼痛轻、康复快的特点,是治疗无脊髓神经损伤的胸腰椎骨折的有效方法。     

微创经皮椎弓根螺钉内固定术治疗胸腰椎骨折的临床疗效分析

目的探讨微创经皮椎弓根螺钉内固定术治疗胸腰椎骨折的临床疗效。方法 2008-03-2010-12采用微创经皮椎弓根螺钉内固定术治疗胸腰椎骨折患者52例,收集患者的围手术期指标、中期随访的影像学指标、腰背疼痛改善情况进行统计学分析。结果所有患者均获得18个月至48个月随访,平均32个月。本组病例手术时间48±22 min,术中出血量为100±25 ml,切口长度68±5.4 mm,住院天数9±2.1 d。所有患者术后疼痛均明显缓解,与术前比较有统计学差异(P<0.05)。手术前后矢状位后凸Cobb角、矢状位指数、伤椎椎体前缘高度的比较均有显著性差异(P<0.05)。术中无一例出现医源性神经根损伤,术后无明显并发症发生。结论微创经皮椎弓根螺钉固定治疗胸腰椎骨折安全可靠、创伤小、出血少、恢复快、住院时间短、术后并发症少。     

Pullout strength of misplaced pedicle screws in the thoracic and lumbar vertebrae - A cadaveric study

Background:

The objective of this cadaveric study was to analyze the effects of iatrogenic pedicle perforations from screw misplacement on the mean pullout strength of lower thoracic and lumbar pedicle screws. We also investigated the effect of bone mineral density (BMD), diameter of pedicle screws, and the region of spine on the pullout strength of pedicle screws.

Materials and Methods:

Sixty fresh human cadaveric vertebrae (D10–L2) were harvested. Dual-energy X-ray absorptiometry (DEXA) scan of vertebrae was done for BMD. Titanium pedicle screws of different diameters (5.2 and 6.2 mm) were inserted in the thoracic and lumbar segments after dividing the specimens into three groups: a) standard pedicle screw (no cortical perforation); b) screw with medial cortical perforation; and c) screw with lateral cortical perforation. Finally, pullout load of pedicle screws was recorded using INSTRON Universal Testing Machine.

Results:

Compared with standard placement, medially misplaced screws had 9.4% greater mean pullout strength and laterally misplaced screws had 47.3% lesser mean pullout strength. The pullout strength of the 6.2 mm pedicle screws was 33% greater than that of the 5.2 mm pedicle screws. The pullout load of pedicle screws in lumbar vertebra was 13.9% greater than that in the thoracic vertebra (P = 0.105), but it was not statistically significant. There was no significant difference between pullout loads of vertebra with different BMD (P = 0.901).

Conclusion:

The mean pullout strength was less with lateral misplaced pedicle screws while medial misplaced pedicle screw had more pullout strength. The pullout load of 6.2 mm screws was greater than that of 5.2 mm pedicle screws. No significant correlation was found between bone mineral densities and the pullout strength of vertebra. Similarly, the pullout load of screw placed in thoracic and lumbar vertebrae was not significantly different.     

Biomechanical comparison of pedicle screws versus spinous process screws in C2 vertebra: A cadaveric study

Background:

Biomechanical studies have shown C2 pedicle screw to be the most robust in insertional torque and pullout strength. However, C2 pedicle screw placement is still technically challenging. Smaller C2 pedicles or medial localization of the vertebral artery may preclude safe C2 pedicle screw placement in some patients. The purpose of this study was to compare the pullout strength of spinous process screws with pedicle screws in the C2.

Materials and Methods:

Eight fresh human cadaveric cervical spine specimens (C2) were harvested and subsequently frozen to −20°C. After being thawed to room temperature, each specimen was debrided of remaining soft tissue and labeled. A customs jig as used to clamp each specimen for screw insertion firmly. Screws were inserted into the vertebral body pairs on each side using one of two methods. The pedicle screws were inserted in usual manner as in previous biomechanical studies. The starting point for spinous process screw insertion was located at the junction of the lamina and the spinous process and the direction of the screw was about 0° caudally in the sagittal plane and about 0° medially in the axial plane. Each vertebrae was held in a customs jig, which was attached to material testing machine (Material Testing System Inc., Changchun, China). A coupling device that fit around the head of the screw was used to pull out each screw at a loading rate of 2 mm/min. The uniaxial load to failure was recorded in Newton''st dependent test (for paired samples) was used to test for significance.

Results:

The mean load to failure was 387 N for the special protection scheme and 465 N for the protection scheme without significant difference (t = −0.862, P = 0.403). In all but three instances (38%), the spinous process pullout values exceeded the values for the pedicle screws. The working distances for the spinous process screws was little shorter than pedicle screws in each C2 specimen.

Conclusion:

Spinous process screws provide comparable pullout strength to pedicle screws of the C2. Spinous process screws may provide an alternative to pedicle screws fixation, especially with unusual anatomy or stripped screws.     

空心带侧孔椎弓根螺钉灌注骨水泥强化技术治疗老年性胸腰椎爆裂性骨折

目的 探讨空心带侧孔椎弓根螺钉灌注骨水泥强化技术治疗合并老年骨质疏松症胸腰椎爆裂性骨折的临床效果。方法 2011-03-2013-06应用空心带侧孔椎弓根螺钉并灌注骨水泥强化治疗合并老年骨质疏松症胸腰椎爆裂性骨折40例。结果 术后疼痛及神经受压症状基本缓解。骨折椎体高度、椎管矢状径恢复满意,未发生伤椎再塌陷,无骨水泥渗漏、脊髓损伤;无螺钉松动、断裂脱出;无腰背痛及功能损失等后遗症状。结论 合并老年骨质疏松症胸腰椎爆裂性骨折患者,应用空心带侧孔椎弓根螺钉并灌注骨水泥强化后进行复位固定治疗,既提升了螺钉的把持力又稳定了脊柱,恢复了脊柱矢状和冠状的几何序列,是一种切实可行、相对微创、有效的方法。     

椎弓根螺钉+髂骨螺钉系统固定治疗骨盆后环不稳

目的探讨椎弓根螺钉结合髂骨螺钉复位固定治疗骨盆后环不稳定的临床疗效。方法对12例骶髂关节骨折(脱位)患者采用后路椎弓根螺钉结合髂骨螺钉复位固定。结果患者骶髂关节均达到解剖复位,未发生血管、神经损伤等并发症。12例均获随访,时间6～16个月。骶髂关节均获融合。结论椎弓根螺钉结合髂骨螺钉固定对于骨盆后环不稳定骨折脱位有良好的复位固定作用,临床疗效良好。     

Cervical pedicle screws vs. lateral mass screws: uniplanar fatigue analysis and residual pullout strengths

BACKGROUND CONTEXT: Although successful clinical use of cervical pedicle screws has been reported, anatomical studies have shown the possibility for serious iatrogenic injury. However, there are only a limited number of reports on the biomechanical properties of these screws which evaluate the potential benefits of their application. PURPOSE: To investigate if the pull-out strengths after cyclic uniplanar loading of cervical pedicle screws are superior to lateral mass screws. STUDY DESIGN: An in vitro biomechanical study. METHODS: Twenty fresh-frozen disarticulated human vertebrae (C3-C7) were randomized to receive both a 3.5 mm cervical pedicle screw and lateral mass screw. The screws were cyclically loaded 200 times in the sagittal plane. The amount of displacement was recorded every 50 cycles. After cyclical loading, the screws were pulled and tensile load to failure was recorded. Bone density was measured in each specimen and maximum screw insertion torque was recorded for each screw. RESULTS: During loading the two screw types showed similar stability initially, however the lateral mass screws rapidly loosened compared to the pedicle screws. The rate of loosening in the lateral mass screws was widely variable, while the performance of the pedicle screws was very consistent. The pullout strengths were significantly higher for the cervical pedicle screws (1214 N vs. 332 N) and 40% failed by fracture of the pedicle rather than screw pullout. Pedicle screw pullout strengths correlated with both screw insertion torque and specimen bone density. CONCLUSIONS: Cervical pedicle screws demonstrated a significantly lower rate of loosening at the bone-screw interface, as well as higher strength after fatigue testing. These biomechanical strengths may justify their use in certain limited clinical applications.     

3种椎弓根螺钉置钉方式治疗无神经损伤的胸腰椎压缩骨折疗效比较

目的比较经皮、经椎旁肌间隙(Wiltse入路)与传统开放3种椎弓根螺钉置钉方式治疗无神经损伤的胸腰椎压缩骨折的疗效。方法将148例单椎、无神经损伤的胸腰椎骨折(AO分型A型)患者根据手术方式不同分为A组(采用经皮椎弓根置钉,67例)、B组(采用Wiltse入路置钉,45例)、C组(采用传统开放置钉,36例)。比较3组手术情况、疼痛VAS评分及影像学参数。结果患者均获得随访,时间12~24个月。手术时间3组比较差异无统计学意义(P>0.05),术中出血量A、B组少于C组(P<0.05),X线透视次数A组多于B、C组(P<0.05)。术后1周及末次随访时,伤椎后凸Cobb角A组大于B、C组(P<0.05),伤椎前缘高度百分比A组低于B、C组(P<0.05)。术后3个月腰痛VAS评分A、B组低于C组(P<0.05)。结论3种椎弓根螺钉置钉方式均是治疗胸腰椎压缩骨折的有效方法,经皮椎弓根置钉和Wiltse入路置钉具有创伤小、患者恢复快、术后腰部疼痛程度轻的优点,但经皮椎弓根置钉术中医患放射线曝露时间长,椎体高度恢复及后凸角度恢复略差。     

诱发肌电图刺激电流阈值与螺钉位置关系模型建立及影响因素分析

目的研究诱发肌电图刺激电流阈值与椎弓根螺钉距离椎弓根内侧壁量化关系方程模型,探讨该方程模型的影响因素。方法对腰椎后路椎弓根固定的58例患者256个螺钉建立刺激电流阈值推算椎弓根螺钉与椎体后壁内侧之间距离的回归方程,同时判断性别、手术材料、麻醉方式及骨质疏松对回归方程的影响。结果刺激电流阈值推算椎弓根螺钉与椎体后壁内侧之间距离的回归方程为y=0.444x-2.28,在距离差异无统计学意义的前提下,不同性别、麻醉方式、螺钉类型组间阈值差异无统计学意义(P0.05),骨质疏松组与非骨质疏松组间阈值差异有统计学意义(P0.05)。结论通过建立诱发肌电图刺激电流阈值与螺钉位置关系模型,可以减少医源性神经根损伤;患者如合并骨质疏松可影响阈值判断。     

经皮微创与常规切开椎弓根螺钉内固定治疗不稳定性胸腰椎骨折的对比研究

背景：随着微创理念在外科临床中的不断深入发展和微创技术的发展,经皮外科技术及经通道外科技术越来越被更多的应用于临床。目的：探讨经皮微创与常规切开椎弓根螺钉内固定治疗不稳定性胸腰椎骨折的临床疗效。方法：2012年7月至2013年6月收治不稳定性胸腰椎骨折患者32例,均为单节段椎体骨折,均未合并其他骨折和脏器损伤、脊髓或神经根损伤。32例患者随机分为2组,16例采用经皮微创椎弓根螺钉内固定（实验组）;16例采用常规切开椎弓根螺钉内固定（对照组）。比较两组患者的手术时间、术中及术后出血量、住院天数、术后切口愈合情况及并发症;比较两组患者术后1、3、6个月的疼痛评分（VAS）;比较两组患者术前、术后1个月、术后3个月、术后6个月的椎体前缘影像学高度及后凸Cobb角的改善情况。结果：所有患者均未出现神经损伤、术后感染、内固定松动、内固定断裂等并发症。两组患者的手术时间无统计学差异;术中及术后出血量、住院天数有统计学差异（P〈0.05）。实验组与对照组患者的术后椎体前缘影像学高度及后凸Cobb角均较术前有明显改善,组间比较无统计学差异。对照组1例患者术后出现椎旁肌内血肿形成经穿刺抽吸,切口局部加压后甲级愈合。结论：经皮微创椎弓根螺钉内固定技术符合微创原则,是治疗单节段无神经损伤胸腰段骨折的有效方法。     

经皮椎弓根钉固定系统治疗胸腰椎压缩性骨折的疗效

目的观察经皮椎弓根钉固定系统治疗胸腰椎压缩性骨折的临床效果。方法采用经皮椎弓根钉固定系统治疗35例胸腰椎压缩性骨折患者,比较手术前后VAS评分、ODI、Cobb角、椎体塌陷率及神经功能Frankel分级。结果患者均获得随访,时间6~18个月。患者术后VAS评分、ODI、Cobb角、椎体塌陷率、神经功能Frankel分级指标均较术前明显改善,差异均有统计学意义(P0.05)。结论经皮椎弓根钉固定系统可用于治疗无明显脊髓神经损伤的胸腰椎骨折。     

后路短节段内固定治疗胸腰段爆裂骨折的疗效分析

[目的]探讨应用后路短节段椎弓根内固定治疗胸腰椎爆裂骨折的适应证。[方法]对2006年10月～2009年12月的48例资料完整的胸腰椎爆裂骨折手术治疗效果进行回顾性研究。按照Magerl分型将病例分为3组,A31型(n=13)、A32型(n=19)和A33型(n=16)。所有患者均行后路切开复位椎弓根系统内固定植骨融合术。于术前、术后及1年后随访时测量患者的椎体前高率、矢状位指数及Cobb角。以视觉疼痛评分(VAS)评价患者腰背痛程度。[结果]所有患者的腰背痛程度随时间延长逐渐减轻,合并脊髓损伤的患者脊髓功能评分均有1级的恢复。术后所有患者的椎体前高率、矢状位指数及Cobb角均有明显改善,与术前相比有统计学上的差异,随访时A31型和A32型骨折影像学参数与术后比较变化不明显,但A33型骨折的患者出现了腰背部后凸畸形明显加重。[结论]应用后路短节段固定治疗对于A31型和A32型胸腰段骨折治疗效果良好,但治疗A33型骨折效果不理想。     

Fenestrated pedicle screws for cement-augmented purchase in patients with bone softening: a review of 21 cases

Background  

This prospective mixed cohort study was designed to evaluate the middle- to long-term purchase of cement-augmented pedicular screws in patients with poor bone quality. The growing number of surgical procedures performed in the spine has highlighted the problem of screws loosening in patients with poor bone stock due to osteoporosis and/or tumors. Different methods of increasing screw purchase have been reported in the literature, including polymethylmethacrylate (PMMA) augmentation.     

经皮椎体后凸成型术与椎弓根螺钉系统治疗胸腰段椎体压缩性骨折的临床疗效比较

目的比较经皮椎体后凸成型术与椎弓根螺钉系统治疗胸腰段椎体压缩性骨折的临床疗效。方法收集我科2003年9月至2005年12月手术治疗的86例胸腰段椎体压缩性骨折患者,根据手术方法不同分为A组(椎体后凸成型术组)和B组(椎弓根螺钉固定组)。A组30例,B组56例,比较两组术前术后椎体前缘、中线、后缘高度变化,疼痛视觉模糊评分(visual analogue painscale,VAS),手术时间,出血量等方面的差异。结果两组对椎体高度的恢复比较没有统计学意义,A组的手术时间和出血量较B组少,差异有统计学意义(P<0.01),VAS A组较B组小(P<0.01)。结论经皮椎体后凸成型术与椎弓根螺钉系统具有相当的治疗椎体压缩性骨折效果,且经皮椎体后凸成型术具有创伤小、手术时间短、出血量少等微创优点。     

后路短节段椎弓根内固定加植骨融合治疗儿童先天性脊柱后凸

[目的]探讨后路短节段椎弓根钉内固定加植骨融合矫正儿童先天性半椎体脊柱后凸畸形的可行性及短期疗效评价。[方法]对2001年11月～2006年1月挑选的13例先天性半椎体脊柱后凸儿童进行后路短节段椎弓根钉内固定加植骨融合畸形矫正术，男8例，女5例；平均10．4岁（5～13岁）。Cobb’s角平均为42．7^o（28^o～48^o）。术后支具固定8个月。[结果]术后X线片随访12个月-5年3个月（平均2年3个月）。矢状面Cobb＇s角由平均42．7^o矫正至平均9．3^o，畸形矫正率达到78．2％。随访过程中矫正的Cobb’s角平均增大1．6^o，无椎弓根切割，无神经损伤，没有发生植骨不愈合的病例，没有患者出现侧凸畸形。[结论]后路短节段椎弓根钉内固定加植骨融合矫正儿童先天性脊柱后凸，手术创伤小，短期效果可靠，但应严格掌握手术指征。     

后路经皮穿刺空心椎弓根螺钉内固定治疗胸腰椎骨折

目的探讨后路经皮穿刺空心椎弓根螺钉内固定治疗胸腰椎骨折可行性及其疗效。方法选择26例损伤平面以下无神经功能损害无需进行椎板减压的单纯胸腰椎骨折患者,Denis三柱分型均为不稳定骨折,后路复位固定手术指针明确。在C臂机定位下行椎弓根穿刺,透视穿刺针,正、侧位片确认位于椎弓根内合适位置,切开皮肤约1.5 cm,依次攻丝,植入万向椎弓根螺钉,撑开、复位和固定。采用视觉模拟疼痛评分(VAS)、功能障碍指数(ODI)以及测量Cobb角评定疗效。结果患者均顺利完成手术,无切口感染、神经根或者脊髓损伤等并发症。手术时间35~80(60±15)min,术中出血量40~110(85±10)ml。患者均获随访,时间18~32个月。VAS术前7.8分±1.1分、术后2.0分±0.6分;Cobb角术前45.1°±3.5°、术后6.3°±3.6°;两项指标与术前比较差异均有统计学意义(P0.05)。术后椎体前缘高度及后凸畸形得到矫正。内固定取出后复查X线Cobb角为7.8°±1.4°,与术后比较差异无统计学意义(P=0.52),椎体高度无明显丢失。术后1个月ODI评分8.0分±0.6分,取出内固定ODI评分6.5分±0.8分(P0.05)。术后12~26个月取出内固定,无内固定断裂患者。结论后路经皮穿刺空心椎弓根螺钉内固定技术适合无需减压(或椎管探查)的胸腰椎骨折。