下颈椎后路3种固定技术的拔出强度研究

目的评价下颈椎后路侧块螺钉、椎弓根螺钉、经关节螺钉3种固定方法的拔出强度。方法6具新鲜颈椎尸体标本（C3～C7）,分别用侧块螺钉Roy-Camille法（LMS）、椎弓根螺钉（TPS）和经关节螺钉植入法（TAS）拧入螺钉,使用万能材料实验机,以100、200、300、400、500、600N分级加载,以18mm/min加载速度进行螺钉拔出实验,测试其最大拔出力、最大拔出能量。结果LMS最大拔出力为（426±38）N,最大拔出能量为（5.26±0.39）J;TPS最大拔出力为（502±42）N,最大拔出能量为（7.18±0.67）J;TAS最大拔出力为（482±40）N,最大拔出能量为（6.68±0.47）J。LMS的最大拔出力和最大拔出能量均小于TPS和TAS（P〈0.05）,而TPS和TAS之间相近,差异无统计学意义（P〉0.05）。结论经关节螺钉拔出强度优于侧块螺钉,而椎弓根螺钉拔出强度最大。     

两种长度的颈椎椎弓根螺钉与侧块螺钉拔出试验比较

目的:比较两种长度的颈椎椎弓根螺钉和侧块螺钉的抗拔出力,探讨颈椎经椎弓根短螺钉固定的可行性。方法:5具C3~C5共15节新鲜颈椎标本,用长度为28mm和20mm的皮质骨螺钉分别置入椎弓根,并用20mm的螺钉行侧块双皮质固定,螺钉进入侧块深度约14mm。行拔出试验,比较螺钉的最大轴向拔出力。结果:椎弓根长螺钉的最大拔出力为650N,椎弓根短螺钉为585N,两者比较无显著性差异(P>0.01);侧块螺钉的最大拔出力为360N,与椎弓根短螺钉比较有显著性差异(P<0.0001)。结论:颈椎椎弓根短螺钉固定可提供足够的稳定性,其安全性相对较高。     

下颈椎前路椎弓根螺钉固定系统与普通前路椎体螺钉固定系统的静力学比较

目的：比较下颈椎前路椎弓根螺钉（ATPS）锁定固定系统和普通前路椎体螺钉（VBS）锁定固定系统的静力学特性。方法：采集新鲜颈椎标本16具,分解为C3.,4,C4,5,C5,6,C6,7共32个运动节段（functionalspinalunit,FSU）,其中C3,4,C4,5,C5,6,C6,7各8个。将其按照不同节段随机分成A、B两组,对所获标本椎间盘切除后模拟植骨,分别植入自行设计生产的下颈椎前路椎弓根螺钉配套钢板系统和普通颈椎前路椎体螺钉钢板系统。在生物力学试验机上行钢板的垂直拔出强度试验。结果：下颈椎前路椎弓根螺钉的最大轴向拔出力为（604．68±48．76）N,椎体螺钉为（488．24±32．42）N,两者比较差异有统计学意义（t=2．147,P〈0．05）,前路椎弓根螺钉固定系统与椎体螺钉固定系统在各FSU间差异无统计学意义（A组和B组的F值分别为2．27、2．05,P〉0．05）。结论：下颈椎前路椎弓根螺钉钢板系统的拔出力明显优于普通前路椎体螺钉钢板系统,从生物力学角度上来看具有应用可行性。     

颈椎椎弓根皮质骨螺钉固定的钉道影像学测量与生物力学研究测试

【摘要】 目的：探讨颈椎椎弓根皮质骨螺钉在临床使用可行性、钉道的参数和置钉后生物力学分析。方法：随机选取我院2014年1月～2018年6月住院行颈椎CT三维重建的住院患者CT资料30例,男性16例,女性14例,年龄30～60岁（48.0±5.6岁）,采集患者颈椎（选取C4～C6）CT连续扫描数据,测量每个椎弓根的形态学数据：椎弓根高度和宽度;并在图像处理系统上模拟皮质骨螺钉的钉道轨迹,测量每个钉道的侧倾角和头倾角,计算各个椎体皮质骨螺钉置入的角度范围。选用18具完整的成人新鲜颈椎标本（选取C4～C6）,将每一节段颈椎标本左右两侧椎弓根各作为一个测试单元进行随机置钉,置入传统椎弓根螺钉为A组,置入皮质骨通道的螺钉为B组。再将置好螺钉的颈椎标本进行CT平扫,测量并记录A、B组螺钉的平均固定长度,根据Grade标准评估置钉等级。将颈椎标本固定在特制的夹具上,生物力学测试前通过旋转夹具底座的方法来调整螺钉与夹具的角度,检测螺钉的最大垂直轴向拔出力,比较两组结果。结果：30例住院患者C4高度为7.3±0.8mm、宽度为5.5±0.3mm;C5高度为7.4±0.6mm、宽度为5.8±0.2mm;C6高度为7.6±0.6mm、宽度为6.2±0.3mm。模拟置钉测量C4侧倾角为39.5°±2.3°、头倾角为10.3°±0.4°;C5侧倾角为39.3°±1.3°、头倾角为10.9°±0.5°;C6侧倾角为37.6°±0.9°、头倾角为11.7°±0.3°。新鲜颈椎标本CT扫描重建,两组螺钉Grade置钉等级,A组1级52枚,2级2枚,B组1级51枚,2级3枚,差异无统计学意义（P>0.05）。A组的平均固定长度C4为34.2±1.8mm,C5为34.3±2.3mm,C6为34.6±1.9mm;B组的平均固定长度C4为23.3±1.4mm,C5为24.3±2.1mm,C6为25.7±1.3mm,差异无统计学意义（P>0.05）。A组最大拔出力为521.2±15.6N;B组最大拔出力为527.4±18.9N;两组的最大拔出力差异无统计学意义（P>0.05）。结论：CT扫描、图像模拟显示颈椎皮质骨螺钉置入安全可行;颈椎皮质骨螺钉的拔出力与传统椎弓根骨螺钉相比,固定长度差异不大,拔出力相当。     

颈椎经关节椎弓根螺钉固定与标准椎弓根螺钉固定的生物力学比较

目的 比较颈椎经关节椎弓根螺钉固定和标准椎弓根螺钉固定的拔出强度.方法 取10具新鲜尸体颈椎标本(C_3～T_1),游离成三个颈椎运动节段(C_(3,4),C_(5,6),C_7T_1).在椎体两侧随机进行经关节椎弓根螺钉固定或标准椎弓根螺钉固定,置入直径3.5 mm皮质骨螺钉.经关节椎弓根螺钉固定以上位椎骨侧块外下象限中点为进钉点,在直视椎弓根下,螺钉在冠状面内倾约45°、矢状面尾倾约50°.由上位椎骨下关节突经关节突关节、下位椎骨的椎弓根,进入下位椎骨的椎体内.标准椎弓根螺钉固定以侧块外上象限中点为进钉点,在直视椎弓根下,螺钉方向参考CT测量结果 ,尽量与椎弓根倾斜角度保持一致,在横断面上内倾约45°、矢状面上螺钉指向椎体的上1/3.在生物力学试验机上行拔出强度试验,比较两种螺钉固定的最大轴向拔出力.结果 颈椎经关节椎弓根螺钉固定平均最大轴向拨出力为(694±42)N,标准椎弓根螺钉固定为(670±36)N,两者比较差异有统计学意义(P<0.05).结论 颈椎后路经关节椎弓根螺钉固定的拔出强度大干标准椎弓根螺钉固定,从生物力学强度方面考虑经关节椎弓根螺钉固定可以作为标准椎弓根螺钉固定的一种补充方法.     

经骶1-2侧块螺钉固定的最大拔出力测定

【摘要】 目的：测量经骶1-2侧块螺钉固定的最大拔出力,初步探讨该内固定方法的有效性。方法：8具甲醛溶液固定湿润成人骶骨标本,采用双能X线吸收测定仪（dual-energy X-ray absorptiometry, DEXA）测定S1椎体骨密度。在同一骶骨标本上随机置入3种骶骨螺钉：经骶1-2侧块螺钉（A组）、S1椎弓根螺钉（B组）、S1前外骶骨翼螺钉（C组）。将标本固定于858型MTS材料试验机上,对螺钉施加轴向拔出力,根据3种骶骨螺钉轴向拔出实验的数据绘制力（N）-位移（mm）曲线,取曲线的顶点作为最大拔出力数值。应用SPSS 16.0统计软件对3组骶骨螺钉的最大拔出力数值行方差分析。结果：8具骶骨标本S1椎体骨密度为0.43～0.74g/cm3,平均0.641±0.275g/cm3。3种骶骨螺钉固定的螺钉即刻平均最大拔出力：A组为379.62±73.10N,B组为829.12±170.74N,C组为230.62±98.52N,3组之间两两比较差异有统计学意义（P＜0.05）。结论：经骶1-2侧块螺钉固定的最大拔出力低于S1椎弓根螺钉固定,但高于S1前外骶骨翼螺钉固定,当S1椎弓根螺钉固定不能施行时,骶1-2侧块螺钉固定可作为一种有效的选择。     

下颈椎后路经关节螺钉内固定的解剖学研究

目的明确下颈椎后路经关节螺钉固定的技术参数，为临床应用提供参考。方法取20具（男14具、女6具）尸体颈椎标本，仔细解剖颈部的后侧和侧前方，以清晰地暴露颈椎侧块，保护好脊神经前、后支（C2-7）及其与周围结构的关系。确定安全的进、出钉点，从C2.3-C5.6直视下置人经关节螺钉。通过CT重建，测量经关节固定螺钉的角度、长度、螺钉尖与椎动脉的距离，并确定经关节螺钉矢状面的安全进钉角度（sagittal safety angle，SSA）。结果经关节固定螺钉方向在矢状面呈尾倾，冠状面呈外倾，各固定节段间略有不同，但差异无统计学意义（P〉0．05）。下颈椎后路经关节螺钉固定的理想角度为在矢状面尾倾平均37.3^o±5．0^o，在冠状面外倾平均16．6^o±4．6^o。经关节螺钉钉道长度平均为（18．7±1.4）mm，在C2.3，水平螺钉钉道长度与C3.4C4.5C5.6比较差异有统计学意义（P〈0．05）。后路经关节螺钉矢状面安全进钉角度为41．9^o±5．6^o，螺钉钉尖与椎动脉的距离平均为（5．8＋1．5）mm，各固定节段间略有不同，但差异无统计学意义（P〉0．05）。结论下颈椎后路经关节螺钉置钉时要求一定的准确性，可以作为颈椎侧块螺钉和椎弓根螺钉固定的一种补充内固定方法。     

椎弓根螺钉把持椎弓根皮质骨对其固定强度的影响

目的：了解椎弓根螺钉把持椎弓根皮质骨对椎弓根螺钉固定强度的影响。方法：将成年羊腰椎椎弓根48个依据椎弓根皮质骨内径和椎弓根螺钉直径（6．25mm）的相对关系分为三组：A组，螺钉直径小于椎弓根皮质骨内径：B组．螺钉直径超出椎弓根皮质骨内径0.01～0．50mm；C组，螺钉直径超出椎弓根皮质骨内径0.51～1．00mm。每组再根据进钉深度与椎弓根长度（平均约8mm）的相对关系分为Ⅰ（进钉深度为16mm）、Ⅱ（进钉深度为8mm）两组。将椎弓根螺钉置入椎弓根中，观察钉道结构、膨胀情况，测量椎弓根螺钉最大轴向拔出力。结果：椎弓根螺钉置入后，椎弓根发生不同程度膨胀；椎弓根螺纹能够切入皮质骨中；C Ⅰ组最大轴向拔出力比A Ⅰ组和B Ⅰ组大（P〈0．05），C Ⅱ组最大轴向拔出力比A Ⅱ组和B Ⅱ组大（P〈0．05），B Ⅱ组比A Ⅱ组大（P〈0.05）。结论：椎弓根螺钉把持椎弓根皮质骨能够增加椎弓根螺钉的固定强度；且椎弓根螺钉把持椎弓根皮质骨量越大，固定强度越大。     

寰椎后路单或双层皮质骨螺钉固定强度的生物力学评价

目的:测量单层皮质骨和双层皮质骨寰椎侧块螺钉固定与寰椎椎弓根螺钉固定的强度,为临床选择寰椎后路螺钉固定的方式提供生物力学依据。方法:利用12例新鲜的寰椎和第三颈椎标本,进行单层皮质骨和双层皮质骨的椎弓根螺钉或侧块螺钉固定,测试并比较其螺钉拔出强度。结果:双层皮质骨寰椎椎弓根螺钉固定的拔出力最大,为1757.0±318.7N;单层皮质骨寰椎椎弓根螺钉固定(1192.5±172.6N)与双层皮质骨寰椎侧块螺钉固定(1243.8±350.0N)及单层皮质骨C3椎弓根螺钉固定(1121.6±224.6N)的拔出力之间均无明显差异。结论:应用寰椎侧块螺钉固定时宜选用双层皮质骨螺钉固定,而寰椎椎弓根螺钉固定选用单层皮质骨螺钉即可。     

下颈椎经关节螺钉钉棒系统固定的生物力学研究

目的：比较下颈椎三柱损伤后单独经关节螺钉固定（TAS）、经关节钉棒系统同定（TRS）和侧块螺钉钉棒系统固定（LRS）的三维稳定性。方法：12具新鲜颈椎标本．制成C4／5、C5／6节段三柱损伤模型，分别进行单独经关节螺钉（TAS组）、经关节螺钉钉棒系统（TRS组）和侧块螺钉钉棒系统（LRS组）三种方法固定，在非限制性和非破坏性的实验条件下测试其前屈、后伸、左右侧弯和轴向旋转运动状态的稳定性。结果：TAS组和TRS组在各方向的运动范同（ROM）和中性区（NZ）的均数均显著小于完整标本组，差异有统计学意义（P〈0．05）；LRS组在前屈、后伸、侧弯运动中的ROM和NZ与完整标本组比较有显著降低，差异有统计学意义（P〈0．05）；LRS组在旋转运动中的ROM和NZ与完整标本组比较有不同程度的降低，但差异无统计学意义（P〉0．05）。TAS、TRS在各个方向稳定性明显优于LRS组（P〈0．05）。TRS在前屈运动中的ROM和NZ与TAS组比较有所减小，但无统计学意义（P〉0．05）；在后伸、侧弯和旋转运动中，TRS组稳定性明显优于TAS组，有统计学意义（P〉0．05）。结论：在下颈椎三柱损伤选择经关节固定技术时以钉棒形式同定稳定性更好。     

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.     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

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.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

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.