髋部髓内加压螺钉和股骨近端短重建钉置入后的生物稳定性比较：随机对照

背景：髋部髓内加压螺钉和股骨近端短重建钉因手术操作简单,以及针对亚洲人的特殊设计,适合应用于股骨转子间骨折,但是目前缺乏两者临床疗效比较的研究报道。 目的：比较髋部髓内加压螺钉和股骨近端短重建钉置入治疗股骨转子间骨折的效果。 方法：将215例股骨转子间骨折患者抽签随机分为2组干预：髓内加压螺钉组110例,股骨近端短重建钉组105例,通过观察失血量、输血量、手术时间、死亡率、术后并发症、行走能力等指标比较两组的临床疗效。 结果与结论：两组术中失血量、输血量、手术时间及死亡率差异均无显著性意义。髓内加压螺钉组35例能够独立步行,57例需要步行辅助器行走,18例无法行走。股骨近端短重建钉组28例患者能够独立步行,48例需要步行辅助器行走,29例无法行走。髓内加压螺钉组活动功能优于股骨近端短重建钉组(P < 0.05),并发症发生率低于股骨近端短重建钉组。表明髓内加压螺钉相对于股骨近端短重建钉能方便、准确、稳定的进行骨折内固定,并且提供术中加压,促进骨折愈合,并发症率较低,更适合应用于转子间骨折。     

动力髋螺钉与锁定加压接骨板置入内固定治疗高龄老年股骨转子间骨折的效果比较

背景：治疗股骨转子间骨折的内固定有动力髋螺钉、Gamma钉、股骨近端交锁髓内钉等,究竟使用何种内固定目前仍存在争议。 目的：比较传统动力髋螺钉与锁定加压接骨板治疗老年股骨转子间骨折临床疗效的差异。 方法：2007-06/2010-03收治老年股骨转子间骨折96例,分别采用动力髋螺钉与锁定加压接骨板治疗各48例,两组患者性别、年龄、骨折类型、致伤原因等情况匹配。股骨近端锁定加压接骨板采用00Cr18Ni14Mo3不锈钢、Ti6Al4V钛合金或纯钛,部分钛合金或纯钛产品表面经阳极化处理,非灭菌包装。动力髋螺钉内固定弹性模量接近人体骨,耐体液电解,耐腐蚀强,性质稳定。比较两组患者手术时间、术中出血量、伤口引流量、骨折愈合时间及内固定后髋关节功能恢复情况。 结果与结论：与动力髋螺钉组相比,锁定加压接骨板组的手术时间及骨折愈合时间均明显缩短,术中出血量明显减少(P < 0.01)。锁定加压接骨板组髋关节功能恢复优良率显著高于动力髋螺钉组(94.6%,87.9%,P < 0.01)。提示与传统动力髋螺钉相比,锁定加压接骨板内固定治疗高龄股骨转子间骨折生物力学更合理,操作简便、微创、固定稳固、骨折易愈合,尤其适用于骨质疏松或老年患者。     

人工股骨头置换与加压滑动髋螺钉置入治疗高龄患者股骨转子间骨折的比较

目的：比较人工股骨头置换与加压滑动髋螺钉置入治疗高龄股骨转子间骨折的临床疗效。 方法：选择1997-06/2008-06绵阳市中心医院骨科收治的高龄新鲜不稳定型股骨转子间骨折患者60例,男31例,女29例;年龄75~91岁,平均82.6岁。其中行人工股骨头置换及加压滑动髋螺钉内固定治疗各30例,对比观察两组患者住院时间、手术时间、术中出血量、术后引流量、下地活动时间、术后早期并发症、术后内科合并症发展及术后髋关节功能恢复。 结果：60例患者均获得随访,随访时间8个月~9年,平均2.3年。两组患者住院时间和术后引流量相比,差异无显著性意义(P > 0.05);而在手术时间、术中出血量、下地负重活动时间、术后早期并发症、术后内科合并症和髋关节功能恢复、术后1年内死亡率等方面,人工股骨头置换均优于加压滑动髋螺钉置入组(P < 0.05)。 结论：人工股骨头置换可以作为治疗高龄股骨转子间骨折的一种选择,与加压滑动髋螺钉相比,人工股骨头置换时间较短,短期并发症发生率低,置换后关节功能评价较好。     

不同前路中空加压螺纹钉内固定治疗Ⅱ型齿突骨折的生物力学评价★

背景: 目前前路中空加压螺钉固定被认为是治疗齿突骨折的较理想方法。 目的：比较不同前路内固定螺钉的生物力学特性。 设计、时间及地点：随机分组设计，对比观察，于2006-03/09在南方医科大学生物力学实验室完成。 材料：双头螺纹中空加压螺钉和单头螺纹中空加压螺钉均为钛合金材料，由苏州双羊医疗器械有限公司生产制作。 方法：20具防腐尸体头颈复合体(C0~C3)标本，甲醛浸泡不超过3个月，剔除其肌肉、韧带，取其枢椎标本，制成齿突Ⅱ型骨折模型。实验分为2组，双头螺纹螺钉组和单头螺纹螺钉组分别用双头螺纹和单头螺纹中空加压螺钉固定骨折，每组10例。 主要观察指标：测试两种螺钉的剪切刚度和最大拔出力。 结果：双头螺纹螺钉组的剪切刚度明显高于单头螺纹螺钉组(P < 0.01)。而最大拔出力差异无显著性意义(P > 0.05)。 结论：双头螺纹中空加压螺钉治疗齿突骨折具有更强的生物力学稳定性；对于骨质梳松者和手术操作引起钉道扩大的患者，应首选双头螺纹中空加压螺钉。     

数字散斑法加载100 N与500 N测量胫骨干骨折内固定下的位移

背景：以往研究多以传感器研究钢板置入内固定治疗骨折生物力学特点,存在直接接触、精度低等缺点。 目的：以数字散斑法测试成人胫骨加压钢板内固定中骨折断端第4颗和第5颗螺钉在不同拉力条件下的平均位移。 方法：测试之前在所有成人胫骨标本表面喷涂银漆粉,用于数字散斑测量。横行截断胫骨中点,制造胫骨干中段骨折模型。将加压钢板置入胫骨后外侧骨膜下,骨折端两侧各4枚螺钉穿透4层骨皮质。标本分6个状态：A,8枚螺钉加压胫骨内固定(未锯断,模拟骨愈合状态);B,在A组的基础上胫骨中点锯断;C,在B组的基础上去掉上面第1颗螺钉;D,在C组的基础上去掉下面第1颗螺钉;E,在D组的基础上去掉上面第2颗螺钉;F,在E组的基础上去掉下面第2颗螺钉,按A~F组测量顺序进行测量。在100,500 N拉力下,用CSS-44100型电子万能试验机进行加载拉力测量骨折断端近侧第4颗与第5螺钉的位移。 结果与结论：方差分析显示在100 N拉力下(F=3.107),A组与F组比较方差的P < 0.05;在500 N拉力下(F=4.719),A组与F组比较方差的P值< 0.05。说明靠近骨折线的螺钉承受较大的应力,容易断裂,在加压钢板内固定治疗胫骨骨折时,经过推断假定其螺钉直径建议增加1.0~2.0 mm。     

经皮加压钢板系统治疗老年转子间骨折：与动力髋螺钉系统的比较

背景：转子间骨折老年患者多合并骨质疏松和其他慢性疾病,保守治疗极易导致卧床并发症。 目的：评价经皮加压钢板系统内固定治疗老年转子间骨折的疗效。 方法：总结2007-06/2009-06收治经皮加压钢板系统植入治疗的转子间骨折老年患者32例和2007/2011采用动力髋螺钉系统治疗股骨转子间骨折患者40例的临床资料,比较2种方法手术操作时间、术中出血量及Harris评价术后疗效。 结果与结论：经皮加压钢板系统治疗手术操作时间、术中出血量明显少于动力髋螺钉系统治疗,而2组Harris评分优良率接近。说明经皮加压钢板内固定也可有效治疗老年人转子间骨折,且手术操作简单,有利于减少手术并发症发生。     

带变向锁钉掌侧钢板DVRTM在不稳定桡骨远端骨折中的应用

背景：用锁定钉的最终固定依赖于钢板的放置,为避免螺钉锁入关节,要求在放入螺钉前反复确认骨折块的复位及钢板位置的放置,无疑增加了操作繁琐及螺钉进入关节的风险。 目的：观察新型带变向螺钉的解剖型掌侧锁定钢板DVRTM治疗不稳定桡骨远端骨折的疗效。 方法：21例不稳定桡骨远端骨折患者,AO分型A3型3例,B2型3例,B3型2例,C1型3例,C2型5例,C3型5例。受伤后0~12 d采用带变向螺钉的解剖型掌侧锁定钢板DVRTM治疗。 结果与结论：随访至24周时,所有患者均获得骨性愈合,无软组织并发症,无螺钉移位及钢板断裂,影像学及功能评估满意。据此得出,对于不稳定桡骨远端骨折,这种固定方式能提供解剖复位、固定确切、并发症发生率低,钉板之间能更灵活、弹性的搭配。     

三维成像辅助支持钢板置入内固定治疗胫骨平台骨折

背景：复杂的关节内骨折二维成像不能准确反应损伤特点,依靠三维成像从三维空间清楚准确地观察骨折移位情况,从而能有效指导成功实施骨折内固定。 目的：观察三维C臂术中三维成像辅助支持钢板内固定治疗胫骨平台骨折的临床疗效。 方法：23例胫骨平台骨折患者实施了骨折切开复位支持钢板内固定术,术中三维C臂X光机扫描三维成像监视骨折复位及钢板螺钉位置。观察骨折复位、螺钉位置、切口愈合情况及有无并发症发生。膝关节功能评定采用Rasmussen评分标准。 结果与结论：胫骨平台骨折一次性解剖复位17例,再次复位6例;螺钉位置良好11例,再次调整螺钉位置12例。18例随访3个月,膝关节功能恢复参照Rasmussen评分, 优9例,良8例,可1例,优良率94%。提示胫骨平台骨折术中三维成像监视能实时细微地从冠状面矢状面横断面3个断层切面及立体三维重建了解骨折复位及内固定情况,有效提高了骨折解剖复位和内固定位置正确性,为膝关节功能恢复提供了良好的基础条件。     

老年踝关节旋后外旋型骨折金属植入物内固定方式及内固定物选择

背景：为了恢复关节的功能,移位的旋后外旋型踝关节骨折常常需要切开复位内固定。老年人由于存在骨质疏松,实施内固定存在一定困难,而且容易出现伤口并发症。 目的：探讨老年移位的踝关节旋后外旋骨折手术治疗方式及内固定物的选择。 方法：选择北京大学第一医院骨科收治的移位踝关节旋后外旋型骨折患者128例,其中单纯外踝骨折29例,双踝骨折52例,三踝骨折47例。外踝选用前外侧切口98例,后外侧切口30例;后侧防滑接骨板固定6例,加压螺钉与中和接骨板固定122例(其中1/3管状接骨板98例,锁定接骨板24例);内踝骨折均使用空心加压螺钉固定;后踝骨折通过后外侧切口复位固定24例。术后根据骨折稳定情况,选择是否使用石膏外固定。随访时,根据X射线平片评估骨折愈合情况,采用Olerud and Molander评分系统进行评定。 结果与结论：128例患者均获得随访,随访时间12~25个月,骨折均愈合。外踝伤口延迟愈合5例(4%),其中锁定接骨板固定者3例、1/3管状板2例,两者间差异无显著性意义(P > 0.05)。无深部感染发生。骨折愈合后关节功能评分优55例,良61例,可10例,差2例,优良率91%。骨折愈合后,因局部不适取出内固定物31例,其中管状接骨板19例,锁定接骨板12例,两者相比,差异有显著性意义(P < 0.05)。在取出的12例锁定接骨板中,2例(17%)发生螺钉与接骨板间的“冷焊接”。1例防滑接骨板固定后出现腓骨肌腱炎,保守治疗后疼痛缓解。提示针对老年人移位的踝关节旋后外旋型骨折,合理选用手术入路和内固定物有利于减少伤口的并发症,解剖复位和良好的内固定有利于骨折恢复。     

数字散斑法测量加载100 N与400 N肱骨干骨折钢板固定下的位移

背景：将光学测量技术数字散斑相关方法应用到生物医学领域中,能更精确地分析螺钉断裂的特点。 目的：以数字散斑法测量肱骨钢板螺钉的位移。 方法：取4根肱骨制造肱骨中段骨折模型。将骨折标本进行复位,用8孔钢板固定,骨折线两端各使用4枚螺钉固定。分别在100及400 N拉力下,将模型设计成骨折前后的5种状态,即状态a是未骨折加压钢板坚强内固定组(模拟骨折愈合,未锯断);状态b是骨折后近端去1枚螺钉;状态c是在状态b的基础上远端去1枚螺钉;状态d是在状态c的基础上近端去1枚螺钉;状态e是在状态d的基础上远端去1枚螺钉。分别测量骨折线两端两枚螺钉的位移,通过相关软件计算位移。 结果与结论：在100 N及400 N拉力下,骨折线旁对称分布的两枚螺钉随着其他螺钉的减少,所产生的位移差异存在显著性意义(P < 0.01);骨折线旁成对称分布的两枚螺钉所承受的应力差异无显著性意义(P > 0.05)。提示骨折线两端的2枚螺钉是承受较多应力的部位(应力集中),易于发生断裂,应选用比现有螺钉的直径增大1.0~2.5 mm的螺钉,增加骨折线旁的固定螺钉稳定性以避免断钉等后遗症。     

Short-segment Pedicle Instrumentation of Thoracolumbar Burst-compression Fractures; Short Term Follow-up Results

Objective

The current literature implies that the use of short-segment pedicle screw fixation for spinal fractures is dangerous and inappropriate because of its high failure rate, but favorable results have been reported. The purpose of this study is to report the short term results of thoracolumbar burst and compression fractures treated with short-segment pedicle instrumentation.

Methods

A retrospective review of all surgically managed thoracolumbar fractures during six years were performed. The 19 surgically managed patients were instrumented by the short-segment technique. Patients'' charts, operation notes, preoperative and postoperative radiographs (sagittal index, sagittal plane kyphosis, anterior body compression, vertebral kyphosis, regional kyphosis), computed tomography scans, neurological findings (Frankel functional classification), and follow-up records up to 12-month follow-up were reviewed.

Results

No patients showed an increase in neurological deficit. A statistically significant difference existed between the patients preoperative, postoperative and follow-up sagittal index, sagittal plane kyphosis, anterior body compression, vertebral kyphosis and regional kyphosis. One screw pullout resulted in kyphotic angulation, one screw was misplaced and one patient suffered angulation of the proximal segment on follow-up, but these findings were not related to the radiographic findings. Significant bending of screws or hardware breakage were not encountered.

Conclusion

Although long term follow-up evaluation needs to verified, the short term follow-up results suggest a favorable outcome for short-segment instrumentation. When applied to patients with isolated spinal fractures who were cooperative with 3-4 months of spinal bracing, short-segment pedicle screw fixation using the posterior approach seems to provide satisfactory result.     

Establishment of a rat model of chronic thoracolumbar cord compression with a flat plastic screw

Previous studies of animal models of chronic mechanical compression of the spinal cord have mainly focused on cervical and thoracic lesions, but few studies have investigated thoracolumbar injury. The specific pathophysiological mechanism of chronic thoracolumbar cord injury has not yet been elucidated. The purpose of this study was to improve animal models of chronic thoracolumbar cord compression using the progressive screw. A custom-designed flat plastic screw was implanted in the spinal cord between thoracic vertebrae 12 and lumbar 1 of rats. The screw was tightened one complete turn(0.5 mm) every 7 days for 4 weeks to create different levels of chronic spinal cord compression. Following insertion of the screw, there was a significant decline in motor function of the hind limbs, and severe stenosis of micro-computed tomography parameters in the spinal cord. Cortical somatosensory evoked potential amplitudes were reduced remarkably, and latencies were prolonged at 30 minutes after surgery. The loss of motor neurons in the gray matter was marked. Demyelination and cavitation were observed in the white matter. An appropriate rat model of chronic thoracolumbar cord compression was successfully created using the progressive screw compression method, which simulated spinal cord compression injury.     

加压螺丝钉内固定股骨颈骨折的蠕变实验

背景：弄清模拟股骨颈骨折单头加压螺丝钉单钉固定,双钉固定,双钉固定植骨后对股骨蠕变力学性质影响对于新型股骨颈骨折内固定器械的研究和股骨颈骨折内固定术式的选择都具有一定的参考价值。 目的：观察加压螺丝钉单钉固定、双钉固定、双钉固定后在骨折区植骨3种方法对股骨颈骨折蠕变特性的影响。 设计、时间及地点：随机对照观察,于2006-08/09在吉林大学力学实验中心完成。 材料：取正常国人急性头部创伤致死的新鲜尸体股骨标本24个,由白求恩医科大学解剖教研室提供。 方法：24个标本随机分为3组,单钉固定组：单钉固定位于模拟骨折面中部;双钉固定组：2枚钉分别位于颈部张力侧;双钉固定植骨组：在双钉固定基础上于骨折线前部垂直骨折线开槽,每组8个标本。以0.5 GPa/min的应力增加速度对标本施加应力,设定时间7 200 s,采集100个实验数据,以回归分析的方法计算归一化蠕变方程。 主要观察指标：各组标本蠕变数据和曲线,蠕变与时间的变化规律。 结果：①蠕变实验结果表明,单钉固定组初始蠕变量为0.493 7%,双钉固定组初始蠕变量为0.402 3%,双钉固定植骨组初始蠕变量为0.382 1%,初始蠕变量大说明其初始位移大,稳定性不好。②单钉固定组7 200 s蠕变量为0.226%,双钉固定组为0.212%,双钉固定植骨组为0.219%。③各组蠕变曲线是以指数关系变化的,在最初600 s变化较快,随时间延长应变缓慢上升,最后进入平衡阶段。 结论：单钉固定、双钉固定和双钉固定植骨3种方法对股骨颈骨折蠕变的影响无明显差异。     

Acute nerve compression during limb ischaemia--an experimental study

In 6 baboons the deep peroneal nerve was compressed for 1 hr by a weighted cord laid over the leg just above the ankle. The procedure was carried out on both sides in a single experiment. On one side the whole leg was rendered ischaemic by a cuff round the thigh which was maintained for 3 or 4 hr before and during the period of nerve compression at the ankle. As judged by the severity of the conduction block at the ankle 24 hr later, and its subsequent recovery, the compressed nerves which were also made ischaemic fared no worse than those subjected to compression alone. Histological studies showed evidence of selective damage to large myelinated fibres during the compression; this damage was not increased on the ischaemic side. There is thus no evidence that ischaemia increased the susceptibility of nerve fibres to mechanical damage in these experiments.     

Establishment of a rat model of chronic thoracolumbar cord compression with a lfat plastic screw

Previous studies of animal models of chronic mechanical compression of the spinal cord have mainly focused on cervical and thoracic lesions, but few studies have investigated thoracolumbar injury. The speciifc pathophysiological mechanism of chronic thoracolumbar cord injury has not yet been elucidated. The purpose of this study was to improve animal models of chronic thoracolumbar cord compres-sion using the progressive screw. A custom-designed lfat plastic screw was implanted in the spinal cord between thoracic vertebrae 12 and lumbar 1 of rats. The screw was tightened one complete turn (0.5 mm) every 7 days for 4 weeks to create different levels of chronic spinal cord compression. Following insertion of the screw, there was a signiifcant decline in motor function of the hind limbs, and severe stenosis of micro-computed tomography parameters in the spinal cord. Cortical somatosensory evoked potential amplitudes were reduced remark-ably, and latencies were prolonged at 30 minutes after surgery. The loss of motor neurons in the gray matter was marked. Demyelination and cavitation were observed in the white matter. An appropriate rat model of chronic thoracolumbar cord compression was successfully created using the progressive screw compression method, which simulated spinal cord compression injury.     

伤椎椎弓根置钉治疗胸腰椎压缩性骨折的三维有限元分析*

背景：有文献报道伤椎置钉技术较传统4钉跨阶段固定具有更强的牢固性,可有效避免内固定的松动断裂,但其生物力学机制研究尚显不足。 目的：构建脊柱胸腰椎单纯压缩性骨折的三维有限元模型,探讨伤椎附加椎弓根螺钉置入治疗胸腰椎压缩性骨折的生物力学效应。 方法：将一T12椎体压缩性骨折患者脊柱胸腰段超薄CT扫描数据输入Mimics软件中,构建T12椎体压缩性骨折的有限元模型,在此模型基础上模拟伤椎置6钉和跨节段4钉内固定,对两个模型分别施加垂直压缩、前屈、后伸、左屈及右旋载荷。 结果与结论：两组固定模式各种载荷下的应力均集中在螺钉根部,在垂直载荷下,螺钉的应力最小,右旋和左屈载荷下的应力最大;在垂直压缩、前屈、后伸、左侧弯及右旋运动下,上位螺钉较下位螺钉应力大(P < 0.05)。伤椎置6钉固定组螺钉应力较跨节段4钉固定组小(P < 0.05)。两组T11椎体最大位移无差别。表明伤椎附加椎弓根螺钉置入可以优化内固定的载荷,减少断钉率。     

Management of Traumatic C6-7 Spondyloptosis with Cord Compression

A case of total spondyloptosis of the cervical spine at C6-7 level with cord compression is described in a 51-year-old male. Because the bodies of C6 and 7 were tightly locked together, cervical traction failed. Then the patient was operated on by a posterior approach. Posterior stabilization and fusion were performed by C4-5 lateral mass and C7-T1 pedicle screw fixation and rod instrumentation with bridging both C4-5''s rods to the C7-T1''s extended ones. After C6 total laminectomy and foraminotomy, the C6 body was returned to its proper position. Secondly, anterior stabilization and fusion were performed by C6-7 discectomy with a screw-plate system. A postoperative lateral plain radiograph showed good realignment. In this case, we report the clinical presentation and discuss the surgical modalities of C6-7 total spondyloptosis and the failed close reduction.     

A Case of Pedicle Screw Loosening Treated by Modified Transpedicular Screw Augmentation with Polymethylmethacrylate

We report a case of pedicle screw loosening treated by modified transpedicular screw augmentation technique using polymethylmethacrylate (PMMA), which used the anchoring effect of hardened PMMA. A 56-year-old man who had an L3/4/5 fusion operation 3 years ago complained of continuous low back pain after this operation. The computerized tomography showed a radiolucent halo around the pedicle screw at L5. We augmented the L5 pedicle screw with modified pedicle screw augmentation technique using PMMA and performed an L3/4/5 pedicle screw fixation without hook or operation field extension. This modified technique is a kind of transpedicular stiffness augmentation using PMMA for the dead space around the loosed screw. After filling the dead space with 1-2 cc of PMMA, we inserted a small screw. Once the PMMA hardened, we removed the small screw and inserted a thicker screw along the existing screw threading to improve the pedicle screws'' pullout strength. At 10 months'' follow-up, x-ray showed strong fusion of L3/4/5. The visual analogue scale (VAS) of his back pain was improved from 9 to 5. This modified transpedicular screw augmentation with PMMA using anchoring effect is a simple and effective surgical technique for pedicle screw loosening. However, clinical analyses of long-term follow-up and biomechanical studies are needed.     

Posterior percutaneous transarticular stand-alone screw instrumentation of C1-C2 with endoscopic assistance: A report of two cases

We present two cases of minimally invasive posterior transarticular screw fixation of C1-C2. The points for screw insertion were visualized by endoscopy via the instrumental port. A patient with a type III odontoid fracture with subluxation underwent a minimally invasive posterior stand-alone transarticular screw fixation. Despite the application of compression screws, for technical reasons, only minimal compression on the anterior third of the C1-C2 lateral joint was achieved. However, complete fracture fusion was achieved with stable fibrous C1-C2 fusion 2.5 years postoperatively. A second patient with a chronic type II odontoid fracture underwent percutaneous C1-C2 fixation by the same method. After 2 years, fracture fusion and C1-C2 lateral mass ankylosis were achieved. The use of a tubular retractor and endoscopy in stand-alone screw fixation of C1-C2 allows direct visualization of the screw entry point and decreases surgical trauma. This procedure might be an alternative to other methods of transarticular instrumentation.