下颈椎经关节螺钉钢板固定的生物力学研究

目的:研究下颈椎单独经关节螺钉固定与经关节螺钉钢板固定的三维稳定性之间的差异。方法:12具新鲜人体颈椎标本,制成C4,5、C5,6节段三柱损伤模型。随机选取6具标本在C4,5、C5,6行单独经关节螺钉固定,另6具标本在C4,5、C5,6行经关节螺钉钢板固定。在非限制性和非破坏性的试验条件下测试它们在前屈、后伸、左右侧弯和轴向旋转运动状态的稳定性,分别测试标本损伤模型制作前完整标本组(A组)、单独经关节螺钉固定组(B组)和螺钉钢板组(C组)3组数据。结果:单独经关节螺钉固定组和经关节螺钉钢板固定组在各方向的运动范围(ROM)和中性区(NZ)的均数均小于完整标本组,差异有统计学意义(P0.05)。经关节螺钉钢板固定在前屈运动中的ROM和NZ与单独经关节螺钉固定比较,差异无统计学意义(P0.05);在后伸、左右侧弯和轴向旋转运动中,经关节螺钉钢板固定的稳定性优于单独经关节螺钉固定,差异有统计学意义(P0.05)。结论:下颈椎经关节螺钉钢板固定的稳定性优于单独经关节螺钉固定,在使用下颈椎经关节螺钉时,相对于单独螺钉固定,建议以螺钉钢板形式固定。     

寰枢椎后路四种钉棒固定方法的三维稳定性评价

目的：评价寰枢椎后路四种不同钉棒固定方法的生物力学稳定性。方法：6具人体新鲜颈椎标本，切除齿状突及寰枢间韧带等结构制造寰枢椎失稳模型．对每具标本先后进行5种方式固定：A组（双侧C1椎弓根螺钉＋C2，3经关节螺钉）、B组（C1椎弓根螺钉＋C2侧块螺钉）、C组（C1椎弓根螺钉＋C2椎弓根螺钉）、D组（C1椎弓根螺钉＋C2椎板螺钉）；与对照组E组（Magerl螺钉．即经C1/2侧块关节螺钉）进行对比，在脊柱三维运动实验机上测量比较其寰枢椎间的屈伸、侧屈、旋转三维稳定性。结果：在前屈稳定性上，四种钉棒固定方法（A、B、C、D组）间无差异（P〉0．05）．且均优于单纯Magerl螺钉固定（E组）（P〈0．05）。在后伸稳定性上．D组与E组两种固定方法间无差异（P〉0．05），其抗后伸的稳定性较A、B、C组略差（P〈0．05）；A、B、C组三种钉棒固定方法间无差异（P〉0．05）。在侧屈运动稳定性上．D组的稳定性略差，其他四种固定方式间无差异（P〉0．05）。在旋转稳定性上，所有固定方式间无统计学差异（P〉0．05）。结论：四种钉棒固定方法都具有可靠的三维稳定性．临床应用时可以根据患者的个体解剖结构情况和术者对不同手术技术的熟悉程度进行选择。     

L5S1前路椎间融合生物力学稳定性实验研究

[目的]对腰椎完整标本、单纯腰椎前路椎间融合术（ALIF）、ALIF分别行椎弓根钉固定及经椎板关节突螺钉固定4种状态进行测试，比较生物力学稳定性。[方法]采用新鲜腰椎标本8具，分别于完整状态、L5S1前路植以Cage、L5S1前路Cage分别行椎弓根钉固定及经椎板关节突螺钉固定下，测定前屈、后伸、侧弯及扭转运动下运动范围并进行比较。[结果]单纯ALIF标本同完整标本相比，其后伸运动范围增大（P〈0．01），而前屈、侧弯、扭转运动范围减小（P〈0．01）；而ALIF经椎弓根钉固定或经椎板关节突螺钉固定后各方向运动范围均小于完整标本及单纯ALIF标本（P〈0．01）。[结论]L5S1单纯行ALIF后伸稳定性差，为增加其稳定性，经椎板关节突螺钉应当是首选的内固定器械。     

生物衍生肌腱双侧关节突交叉固定动力重建颈椎后柱动态稳定性的体外生物力学研究

目的对于颈椎后柱不稳定进行动态稳定性重建研究鲜有报道。探讨采用冻干处理的生物衍生肌腱动力重建颈椎后柱动态稳定性的生物力学性能。方法收集死亡捐献者残肢掌长屈肌腱及掌伸肌腱制备生物衍生肌腱。20个新鲜成年山羊颈椎标本(C1～7),随机分为4组,每组5个标本。A组为完整标本组,B组为损伤模型组,C组为后柱钉棒固定组,D组为肌腱动力重建组。B、C、D组通过破坏颈椎后方韧带复合体制作屈曲分离型损伤模型,C组用侧块螺钉经后路固定,D组用生物衍生肌腱行侧块经关节突交叉固定。用脊柱三维运动测量系统测算各组标本C3、C4节段前屈、后伸、侧屈、旋转的运动范围(range of motion,ROM)。结果前屈运动:C组ROM明显小于其他3组,差异有统计学意义(P<0.05);B组ROM较A、D组明显增加,差异有统计学意义(P<0.05);A、D组间比较差异无统计学意义(P>0.05)。后伸、侧屈、旋转运动:C组ROM明显小于其他3组,差异有统计学意义(P<0.05);其他3组间比较差异无统计学意义(P>0.05)。结论新鲜成年山羊颈椎标本行生物衍生肌腱侧块经关节突交叉固定,能够限制颈椎过度前屈,完全保留后伸运动,不限制侧屈和旋转运动,重建屈曲分离型损伤下颈椎的动态稳定性。     

寰椎椎弓根螺钉联合经寰枢关节螺钉内固定稳定性的生物力学研究

【摘要】 目的：评估寰椎椎弓根螺钉联合经寰枢关节螺钉固定技术的力学稳定性。方法：选取成人颈椎新鲜标本6具,解剖剔除肌肉制备上颈椎完整模型（完整组）,用生物力学测试及计算机视觉分析软件测量在1.5Nm力矩下前屈后伸、左右侧弯和左右旋转时C1-C2的活动度（ROM）;破坏寰椎前弓和侧块制备不稳模型（失稳组）,再次测量相同力矩下各运动方向C1-C2的ROM活动度。随后暴露寰枢椎置钉点,根据先后顺序置入寰椎椎弓根螺钉+枢椎椎弓根螺钉固定（C1P+C2P组）、单纯经寰枢关节螺钉固定（TA组）、寰椎椎弓根螺钉+经寰枢关节螺钉固定（C1P+TA组）,依次分别测量相同力矩下各运动方向C1-C2的ROM,比较各组C1-C2 ROM的差异。结果：失稳组相较于完整组在六个方向上有更大的ROM,两组所有方向上的ROM均有显著性差异（P<0.05）;C1P+C2P组、C1P+TA组、TA组与失稳组比较,所有方向上的ROM均有显著性减少（P<0.05）,三组间比较,前屈、后伸、左旋转和右旋转方向上的ROM存在统计学差异（P<0.05）,C1P+TA组相似文献   

颈椎前路静力性与动力性钉板系统在三柱不稳定损伤中生物力学性能的比较

目的比较颈椎前路静力性、动力性钉板系统在三柱屈曲牵张型不稳定损伤中的生物力学测试结果，为临床提供生物力学依据。方法采用6具小牛颈椎标本，在C4、5节段制作屈曲牵张损伤模型，切除椎间盘、植骨后，随机分为3组，分别采用Orion、Codman、Window钢板螺钉固定，分别测定正常颈椎及固定后脊柱在前屈、后伸、旋转运动时的稳定性并与正常标本比较。结果3种钢板固定后的活动度（ROM）与正常颈椎相比要大。其中Orion在前屈、后伸、侧屈与正常相比无显著的差异（P〉0．05）；Codman和Window在前屈、后伸时与正常相比有显著的差异（P〈0．05）；Codman在侧屈时正常相比无显著的差异（P〉0．05），Window侧屈时与正常相比有显著的差异（P〈0．05）；3种钢板在旋转时与正常相比均有显著的差异（P〈0．05）。结论在三柱屈曲牵张型不稳定损伤的模型中，前路静力化固定相对稳定，动力化固定可能降低一定的固定强度，尤其是选择平移类设计的钢板固定应慎重。     

后路寰椎侧块螺钉联合枢椎椎板钩内固定的生物力学稳定性

目的研究后路寰椎侧块螺钉联合枢椎椎板钩内固定的生物力学稳定性。方法取6例新鲜尸体颈椎标本,每具标本分别依次进行完整(正常组)、寰枢椎不稳(失稳组)、寰枢侧块螺钉联合枢椎椎弓根螺钉钉棒固定(Harms组)、寰椎侧块螺钉联合枢椎椎板钩固定(钉钩组)状态的生物力学测试,每组6个标本,将各标本装载在脊柱三维运动机上,分别施予1.5 N·m力矩,记录标本在前屈后伸、左右侧曲、左右旋转3个方向上的活动度(ROM),比较各组ROM。结果相对于正常组标本,失稳组标本在上述3个方向上的ROM显著增大;相较于正常和失稳组标本,Harms组和钉钩组的标本在上述3个方向上ROM显著减小;钉钩组与Harms组间在上述3个方向的ROM差异无统计学意义(P0.05)。结论后路寰椎侧块螺钉联合枢椎椎板钩内固定在生物力学稳定性上与Harms固定相似,可以起到良好的固定效果。     

三种后路寰枢椎融合术的离体生物力学研究

目的 通过离体生物力学研究方法,比较3种后路寰枢椎融合技术的力学稳定性.方法 将8具新鲜尸体的颈椎标本(C1～4)置于1.5 Nm载荷下,测量C1、2关节的三维运动范围(ROM).每具标本依双侧经寰枢关节间隙螺钉结合Gallie内固定术、双侧经寰枢关节间隙螺钉结合寰椎椎板钩内固定术、双侧寰椎侧块螺钉结合枢椎椎弓根螺钉内固定术的顺序实施固定,每次固定后测量三维运动范围.结果 包含经寰枢关节间隙螺钉的内固定组在旋转和侧屈方向上具有最小的ROM角度,其中新型的双侧经寰枢关节间隙螺钉结合寰椎椎板钩内固定组在前屈后伸运动方向上也具有最小ROM角度.寰椎侧块螺钉结合枢椎椎弓根螺钉内固定组在旋转方向上ROM角度显著大于单独经寰枢关节螺钉内固定组,但在侧屈和前屈后伸方向上ROM角度近似于经寰枢关节间隙螺钉,差异无统计学意义.结论 双侧经寰枢关节间隙螺钉结合寰椎椎板钩内固定术具有最强的生物力学稳定性;双侧寰椎侧块螺钉结合枢椎椎弓根螺钉内固定术与双侧经寰枢关节间隙螺钉结合寰椎椎板钩内固定技术比较,具有相似的力学稳定性.     

单平面和多平面截骨术治疗脊柱后凸的生物力学特征

目的探讨单平面截骨Dick钉固定和多平面截骨Luque棒固定治疗脊柱后的生物力学特点。方法12具新鲜小牛胸腰段脊柱标本（T8-L5）随机分成完整组（INT组），单平面截骨Dick钉固定组（Dick组）和多平面截骨Luque棒固定组（Luque组），每组4具。进行生理负荷下的前屈、后伸、左右侧弯、顺逆时针轴向旋转6种运动范围（ROM）的测试，记录载荷值的变化，对ROM值进行统计学分析。结果在生理负荷下，两种术式的脊柱标本的屈伸和侧弯运动的稳定性均达到或超过完整组标本，其中多平面截骨Luque棒固定组的稳定性更好；在轴向旋转稳定性上，两种术式的标本稳定性均不能达到完整组水平。结论实验中多平面截骨Luque棒固定的稳定性稍优于单平面截骨Dick钉固定组，但不足以构成临床应用中决定取舍的依据。     

脊柱改良横突钩棒系统的生物力学研究

[目的]验证横突钩棒系统的有效性,为其临床应用提供理论基础。[方法]收集5具新鲜冰冻尸体腰椎标本(L1～L5),每个标本分别进行三种状态,也就是自然状态(完整组)、横突钩棒固定状态(钩棒组)、椎弓钉棒固定状态(钉棒组),通过脊柱三维运动系统施加8 N·m力矩使标本产生6个方向的运动,包括前屈、后伸(矢状面)、左右侧弯(冠状面)、左右轴向旋转(水平而),记录活动度(ROM)。[结果] L2/3和L3/4的前屈、后伸、侧弯和旋转各向ROM,完整组最大,钩棒组次之,钉棒组最小。在矢状面ROM,钩棒组与完整组的差异无统计学意义(P0.05),而钉棒组的ROM显著少于前两组(P0.05)。左右侧弯ROM,钩棒组与钉棒组明显小于完整组,差异有统计学意义(P0.05),而钩棒组与钉棒组间差异无统计学意义(P0.05)。左右轴向旋转ROM,钩棒组与钉棒组明显小于完整组,差异有统计学意义(P0.05),而钩棒组与钉棒组间差异无统计学意义(P0.05)。[结论]相比于椎弓根钉棒系统,改良的横突钩棒系统能提供脊柱在冠状面和水平面上类似的稳定性,但保留矢状面部分活动。     

Reduction of Plasma Fibrinogen, Immunoglobulin G, and Immunoglobulin M Concentrations by Immunoadsorption Therapy with Tryptophan and Phenylalanine Adsorbents

Abstract Immunoadsorption (1A) therapy with tryptophan (TR-350) or phenylalanine (PH-350) adsorbents has been used to reduce the concentration of serum antibodies in human lymphocyte antigen (HLA)-immunized patients. Other forms of plasma purification have been reported to reduce the level of fibrinogen, which affects the blood properties. In this study we investigated the effects of IA therapy using both adsorbents on plasma fibrinogen and immunoglobulins G and M in 13 patients (8 patients were treated with TR-350, and 5 patients were treated with PH-350). During each session 1 plasma volume (2.8 ± 0.4 L of plasma) was processed through the immunocolumn and then returned to the patient together with the blood cells. Compared with the pretreatment values, the plasma fibrinogen, IgG, and IgM concentrations were significantly reduced after IA therapy (p < 0.01 for TR-350; p < 0.04 for PH-350). There was a positive correlation between the degree of reduction of plasma proteins and the number of IA treatments given. A nonpara-metric test (Wilcoxon's signed-rank test or the Mann-Whitney test) was used for statistical analysis. We conclude from our study that IA therapy effectively lowers the plasma levels of fibrinogen, IgG, and IgM and thus can be considered a valuable alternative to other blood purification methods.     

The multiply injured child

Blunt trauma is the principal cause of childhood death in many developed countries. This review outlines the differences between adults and children with respect to resuscitation and treatment of orthopaedic injuries in a child with polytrauma. Recent advances in techniques of fracture stabilization are reported.     

Development of Selective Low-Density Lipoprotein (LDL) Apheresis System: Immobilized Polyanion as LDL-Specific Adsorption for LDL Apheresis System

Abstract: Low-density lipoprotein (LDL) is widely recognized as one of the major risk factors for developing coronary heart diseases. Despite intensive development of LDL-lowering drugs, there still exist those patients with refractory hyperlipidemia whose plasma LDL levels are not sufficiently lowered by drugs. LDL apheresis, direct removal of plasma LDL from circulating blood, is thought to be the most promising treatment for such refractory patients. Various techniques, such as the use of an im-munoadsorbent utilizing an anti-LDL antibody, have been used in an attempt to achieve the selective removal of LDL. However, none were widely used because of complications, poor selectivity, and so forth. To establish a safe and effective LDL apheresis system, we chose a synthetic affinity adsorbent as the LDL-removing device. Synthetic polyanion compounds were used as the affinity ligands for LDL adsorbent to simulate the anion-rich sequence of LDL binding sites in the human LDL receptor. Among various polyanion compounds, those polyanions with sulfate or sulfonate groups and hydrophilic backbone were found to have strong affinity for LDL. In contrast, polyanions with carboxyl groups showed poor affinity. Dextran sulfate (DS) was selected as the affinity ligand of LDL adsorbent for its high affinity and low toxicity. The influence of its charge density and molecular weight on its affinity for LDL was suitable. The affinity rapidly increased as the charge density increased, then, reached a constant value. Little affinity was found for either the DS monomer (glucose sulfate) or DS with a molecular weight higher than 10⁴ daltons whereas DS with molecular weights in the midrange showed strong affinity. DS with a midrange molecular weight was immobilized on cellulose hard gel to give LDL adsorbent clinical application. The adsorbent demonstrated an excellent selectivity for LDL and very low density lipoprotein (VLDL) in vitro. Adsorption of high-density lipoprotein and major plasma proteins was almost negligible. Additional study of the LDL-binding mechanism revealed that DS directly interacts with positively charged sites on LDL, which demonstrates that the nature of the interaction is the same as that of LDL receptor. An LDL adsorption column (Liposorber) packed with an LDL adsorbent and polysulfone hollow-fiber plasma separator (Sulflux) was developed as an efficient LDL apheresis system. Clinical investigation proved that this system is capable of intensively lowering the plasma LDL level without affecting major plasma components.     

Artificial organs 2010: a year in review

In this Editor's Review, articles published in 2010 are organized by category and briefly summarized. As the official journal of The International Federation for Artificial Organs, The International Faculty for Artificial Organs, and the International Society for Rotary Blood Pumps, Artificial Organs continues in the original mission of its founders "to foster communications in the field of artificial organs on an international level."Artificial Organs continues to publish developments and clinical applications of artificial organ technologies in this broad and expanding field of organ Replacement, Recovery, and Regeneration from all over the world. We take this time also to express our gratitude to our authors for offering their work to this journal. We offer our very special thanks to our reviewers who give so generously of time and expertise to review, critique, and especially provide such meaningful suggestions to the author's work whether eventually accepted or rejected and especially to those whose native tongue is not English. Without these excellent and dedicated reviewers the quality expected from such a journal could not be possible. We also express our special thanks to our Publisher, Wiley-Blackwell, for their expert attention and support in the production and marketing of Artificial Organs. In this Editor's Review, that historically has been widely received by our readership, we aim to provide a brief reflection of the currently available worldwide knowledge that is intended to advance and better human life while providing insight for continued application of technologies and methods of organ Replacement, Recovery, and Regeneration. We look forward to recording further advances in the coming years.     

Avaliação do clube de revista de anestesiologia por meio de mudanças semânticas

Background and objectives

The interactive approach of a journal club has been described in the medical education literature. The aim of this investigation is to present an assessment of journal club as a tool to address the question whether residents read more and critically.

Methods

This study reports the performance of medical residents in anesthesiology from the Clinics Hospital – University of São Paulo Medical School. All medical residents were invited to answer five questions derived from discussed papers. The answer sheet consisted of an affirmative statement with a Likert type scale (totally disagree–disagree–not sure–agree–totally agree), each related to one of the chosen articles. The results were evaluated by means of item analysis – difficulty index and discrimination power.

Results

Residents filled one hundred and seventy three evaluations in the months of December 2011 (n = 51), July 2012 (n = 66) and December 2012 (n = 56). The first exam presented all items with straight statement, second and third exams presented mixed items. Separating “totally agree” from “agree” increased the difficulty indices, but did not improve the discrimination power.

Conclusions

The use of a journal club assessment with straight and inverted statements and by means of five points scale for agreement has been shown to increase its item difficulty and discrimination power. This may reflect involvement either with the reading or the discussion during the journal meeting.     

Lymphocytapheresis

Abstract: Leukocytapheresis has long been performed with the centrifugal method. But in 1989 in Japan, the Asahi Medical Co. developed the extracorporeal leukocyte-removal filter, Cellsorba. This filter consists of non-woven fabric, which can remove leukocytes from whole blood during extracorporeal circulation. In the incipient stage, this filter was applied to collagen diseases, rheumatoid arthritis, and systemic lupus erythematosus. During the following studies, this filter has been found to have an immunosuppressive effect. Now, it is beginning to be applied to various kinds of autoimmune diseases. Moreover, this filter has recently been recognized to be effective in inflammatory bowel diseases, ulcerative colitis, and Crohn's disease. The outline of Cellsorba and the application of this filter is described here.     

Soluble TNFα Receptors Are Increased in Chronic Renal Insufficiency and Hemodialysis and Inhibit Neutrophil Priming by TNFα

Abstract: The oxidative burst of neutrophils from azotemic patients is refractory to priming by tumor necrosis factor-α (TNFα). Soluble TNFα binding proteins (TNFR) accumulate in the plasma of azotemic patients. To test the hypothesis that these increased sTNFR concentrations inhibit TNFa priming of oxidative burst activity, we measured plasma sTNFR concentrations in nondialyzed azotemic patients, hemodialysis patients, and normal subjects, and determined TNFa priming of fMet-Leu-Phe-stimulated superoxide production in neutrophils incubated in plasma with differing levels of sTNFR. These sTNFR concentrations increased significantly as creatinine clearance decreased and were significantly greater in hemodialysis patients than could be accounted for by loss of renal function alone. TNFα primed superoxide production by normal neutrophils in normal plasma, but this effect was significantly reduced in plasma with increased concentrations of sTNFR. Neutrophils from azotemic and hemodialysis patients were refractory to priming by TNFα in autologous plasma, and incubation in normal plasma only partially corrected this defect. We conclude that sTNFR accumulate as a result of the loss of renal function and hemodialysis and inhibit TNFα priming of neutrophils in azotemic and hemodialysis patients, but that these cells also have an intrinsic functional defect.