带锁髓内钉与锁定加压接骨板固定胫骨近端骨折的有限元分析

目的评估带锁髓内钉(interlocking intramedullary nail,IIN)与锁定加压接骨板(locking compression plate,LCP)固定胫骨近端骨折的生物力学稳定性,为临床治疗方案的选择提供指导。方法按胫骨近端不同位置模拟骨折将其分成A、B、C三组,使用两种不同内固定物分别对骨折模型进行固定并用有限元法分析胫骨骨折模型及内固定物在500N轴向压缩载荷下的位移和等效应力及分布情况。结果 3组模型中使用IIN固定的胫骨骨折模型及胫骨的最大轴向位移均比使用LCP的小;IIN及其固定的胫骨最大等效应力值均比LCP及固定的胫骨的小。且IIN应力分布较均匀,LCP应力集中在骨板与锁定连接处。结论 IIN抗压缩能力强且固定坚强可靠,应力分布较均匀,抗疲劳性好,其固定胫骨近端骨折稳定性优于LCP。     

MIPPO技术下LCP锁定和加压固定后应力遮挡效应的有限元研究

目的 通过比较经锁定和加压固定后骨痂应力的变化,研究LCP锁定固定和加压固定对应力遮挡效应的影响,为临床MIPPO术式中应用不同类型的接骨板和固定方式提供生物力学依据.方法 应用有限元法根据LCP独特设计的锁定与加压结合孔,建立了胫骨上端骨折LCP锁定和加压固定后带骨痂的三维有限元模型.对模型进行力学有限元分析,得出不同工况和内固定方式下骨痂应力情况.结果 骨痂在锁定固定下的应力均值大于加压固定下的应力均值,根据配对t检验的结果 两者差异具有统计学意义(P<0.05).根据应力遮挡率计算公式,锁定固定导致的应力遮挡率小于加压固定导致的应力遮挡率.结论 MIPPO术式下的加压固定可以提供坚强的固定但产生的应力遮挡效应较大;锁定固定产生更少的应力遮挡效应.但没有加压固定那样能提供坚强的固定.因此在临床上对单纯长骨骨折通常采用两端锁定而中间加压的固定方式,这是一种兼顾固定的稳定性与更少的应力遮挡效应的固定方式,有助于骨折愈合.     

MIPPO技术下LCP锁定固定减少锁钉个数后应力遮挡效应的有限元研究

目的比较经锁定固定减少锁钉个数后骨痂应力均值的变化,研究LCP锁定固定减少锁钉个数对应力遮挡效应的影响,为MIPPO术中应用不同类型的接骨板和固定方式提供生物力学依据。方法应用有限元法根据LCP的锁定与加压结合孔,建立胫骨上端骨折LCP锁定固定后带骨痂的三维有限元模型。对模型进行力学有限元分析,得出不同工况和内固定方式下骨痂应力情况。结果骨痂在锁定固定减少2个锁钉条件下的应力均值大于减少1个锁钉条件下的应力均值,根据配对t检验结果两者差异具有统计意义。锁定固定减少2个锁钉导致的应力遮挡率小于减少1个锁钉条件下的应力遮挡率。结论 MIPPO技术下LCP锁定固定均采用锁定钉固定时应该减少不必要的锁钉,使在提供稳定固定的同时减少应力遮挡效应,促进骨痂的生成和骨痂改建塑形,有助于骨折愈合。     

LCP“动力化”一折端微动及应力的有限元分析

[目的]通过三维有限元分析骨折断端微动及应力情况,为LCP(locking compression plates,LCP)"动力化"临床相关应用提供理论依据。[方法]建立骨折近端锁定孔锁定螺钉,远端全锁定螺钉固定(A组);骨折近端锁定孔普通螺钉,远端全锁定螺钉固定(B组);骨折近端加压孔普通螺钉,远端全锁定螺钉(C组)固定胫骨中下段横形骨折的有限元模型,各组分别予以1/6、2/6、3/6、4/6、5/6及1倍体重应力值进行轴向压缩实验,评价各组骨折断端轴向微动距离、胫骨及内固定最大应力以及断端应力值等指标。[结果]相同轴向应力载荷下,胫骨最大应力:AB>C;骨折端轴向微动位移:A相似文献   

锁定加压钢板微创经皮内固定治疗胫骨骨折

目的 探讨锁定加压钢板(LCP)微创经皮内固定治疗胫骨骨折的疗效.方法 采用锁定加压钢板微创经皮内固定治疗胫骨骨折18例,包括胫骨近端骨折7例,胫骨干骨折6例,胫骨远端骨折5例.结果 18例均得到随访,时间6～24个月.根据JoherWruhs评分标准:优15例,良3例.结论 采用锁定加压钢板微创经皮内固定治疗胫骨骨...     

锁定加压接骨板在骨折治疗中的应用

锁定加压接骨板(LCP)是国际内固定研究会基于生物学内固定理念研发的新型内固定系统,其特征是动力加压孔和圆雏形锁定螺纹孔相结合.既能作为单纯AO加压接骨板,用普通螺丝钉对简单骨折行加压固定,也能作为一种内固定支架.运用锁定螺钉对粉碎性骨折行桥接固定.还能对同时有关节内、外骨折或长骨干简单骨折伴发邻近部位粉碎性骨折患者同时进行加压和桥接固定.LCP的临床应用广泛,尤适于治疗骨折部位邻近关节或伴发严重骨质疏松的患者.LCP具有独特的力学特性,临床上如不遵循LCP手术操作原则而盲目使用,仍会导致手术失败.该文就LCP的结构与力学特点、临床应用效果及问题作一综述.     

锁定钢板系统在四肢骨折中的应用

目的 总结微创锁定钢板治疗四肢骨折的疗效.方法 2005年5月至2006年10月,分别采用微创内固定系统(less invasive stabilization system,LISS)与锁定加压钢板(locking compression plate,LCP)对64例70处四肢骨折进行治疗,男45例,女19例;年龄17-69岁,平均36.8岁;股骨远端骨折16例19处,胫骨近端骨折28例31处,胫骨远端骨折8例8处,肱骨近端骨折12例12处.50处股骨远端与胫骨近端骨折采用LISS固定,20处胫骨远端与肱骨近端骨折采用LCP同定.在影像增强器监视下先行闭合复位,复位满意后采用经皮微创接骨术于肌肉下骨膜外置入LISS或LCP,再次确认位置满意后通过导向器经皮拧入锁定螺钉.结果 随访时间4～22个月,平均8.8个月.全部伤口均一期愈合,无一例发生感染、骨折再移位、成角畸形或内固定失败等并发症.骨折临床愈合时间8～16周,平均12.3周.膝关节功能HSS评分70～95分,平均87.5分,ROM 90°～130°,平均122°;踝关节AOFAS评分82～95分,平均91.4分;肩关节功能Neer评分82～94分,平均90.6分.患肢功能均恢复良好.结论 微创技术结合锁定钢板治疗四肢骨折具有软组织创伤小、对骨骼血供影响小、骨折愈合快、手术感染率低、功能恢复好等优点.锁定钢板无须紧贴骨面即可获得可靠的固定,不易发生骨折冉移位或内固定松动.     

锁定加压接骨板治疗肱骨近端骨折46例疗效分析

目的 评价锁定加压接骨板(LCP)治疗肱骨近端骨折的疗效.方法 取肩关节前侧入路,采取切开复位LCP内固定治疗肱骨近端骨折46例,术后早期功能锻炼.结果 全部病例均获随访,骨折均骨性愈合,平均愈合时间8.2周(7～12周),按照Neer评分法评价疗效,优良率为93.48%.结论 应用LCP治疗肱骨近端骨折固定牢靠、操作简单、微创,可早期进行功能功能锻炼,肩关节功能恢复良好,是一种理想的手术方法 .     

股骨近端锁定加压接骨板治疗老年股骨粗隆间骨折63例

目的 评价股骨近端锁定加压接骨板治疗股骨粗隆间骨折的临床效果.方法 应用股骨近端锁定加压接骨板内固定治疗63例老年股骨粗隆间骨折.结果 平均随访12.8个月,骨折均顺利愈合,愈合时间平均14周,关节功能恢复良好.结论 股骨近端锁定加压接骨板治疗老年股骨粗隆间骨折是一种切实可行的治疗方法.     

锁定加压接骨板治疗老年性肱骨近端复杂性骨折

2003年6月至2006年6月,选择本院应用锁定加压接骨板(Locking Compression Plate以下简称LCP)治疗老年性肱骨近端复杂性骨折20例,19例获得随访,效果满意。现报告如下。1资料与方法1.1一般资料:本组资料选择2003年6月至2006年6月,在本院应用锁定加压接骨板治疗老年性肱骨近端复杂性骨折的     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.     

The analgesic effect of racemic ketamine in patients with chronic ischemic pain due to lower extremity arteriosclerosis obliterans

Background : Ketamine in sub-dissociative doses has been shown to have analgesic and phantom-Limb pain, where conventional treatment has often failed. Chronic ischemic pain due to lower extremity arteriosclerosis obliterans often responds poorly to analgesics, and the pain-generating mechanisms are not well understood.
Methods : Eight patients with rest pain in the lower extremity due to arteriosclerosis obliterans were given sub-dissociative doses of 0.15, 0.30, or 0.45 mg/kg racemic ketamine and morphine 10 mg as a 5-min infusion on four separate days in a cross-over, double-blind, randomised protocol. Plasma levels of (S)- and (R)-ketamine and their nor-metabolites were analysed with an enantioselective high-performance liquid chromatography (HPLC) method. Pain levels were evaluated with a visual analogue scale (VAS).
Results : Individual pain levels were highly variable during and after all the infusions but the pooled pain levels showed a dose-dependent analgesic effect of ketamine with a transient but complete pain relief in all patients at the highest dose (0.45 mg/ kg). Side-effects, mainly disturbed cognition and perception, were pronounced and dose-dependent. Morphine 10 mg had an analgesic peak at 20 min and 5/8 patients had complete pain relief. The remaining 3 patients also had high baseline pain scores, indicating a higher analgesic potency for the 0.30 and 0.45 mg/ kg ketamine doses than for morphine 10 mg.
Conclusion : We have demonstrated a potent dose-dependent analgesic effect of racemic ketamine in clinical ischemic pain. Due to a narrow therapeutic window, this analgesic effect is probably best utilised in combination with other analgesics.     

Intravenous endotoxin does not increase tissue extravasation of albumin in rats

Background : It is unclear whether activation of the inducible nitric oxide synthase (iNOS) increases or decreases the extravasation of plasma.
Methods : Chloralose anaesthetised male Wistar rats received E. coli lipopolysacharide (LPS), 3 mg kg^-1 i.v., or the corresponding volume of saline, 3 or 5 h before the end of the experiment. Mean arterial pressure (MAP) and heart rate (HR) were recorded. Tissue clearance of radio-labelled albumin, during the last 2 h of each experiment, was determined by a double-isotope method. In separate animals, the serum concentration of nitrite and nitrate was determined, 5 h after LPS or the solvent.
Main Results : LPS initially decreased MAP and lastingly increased HR. In the 3-h LPS animals (n=8), tissue plasma clearance was lower in the heart and calf muscle and increased only in diaphragm, compared to corresponding control animals (n=8). In the 5-h LPS rats, clearance was lowered (n=8) in the entire gastrointestinal tract and in testes, compared to controls (n=8). The serum nitrite/nitrate concentration was higher in animals given LPS (n=6) than in controls (n=6).
Conclusion : After LPS, tissue clearance of albumin was not increased in any major tissue, in spite of increased serum levels of NO end products. Apparently, after activation of iNOS, the augmented release of NO is not necessarily associated with increased albumin extravasation.     

Adrenaline markedly improves thoracic epidural analgesia produced by a low-dose infusion of bupivacaine, fentanyl and adrenaline after major surgery: A randomised, double-blind, cross-over study with and without adrenaline

Background: Basic pharmacological research indicates that there are synergistic antinociceptive effects at the spinal cord level between adrenaline, fentanyl and bupivacaine. Our clinical experience with such a mixture in a thoracic epidural infusion after major surgery confirms this. The objectives of the present study were to evaluate the effects on postoperative pain intensity, pain relief and side effects when removing adrenaline from this triple epidural mixture. Methods: A prospective, randomised, double-blind, cross-over study was carried out in 24 patients after major thoracic or abdominal surgery. Patients with only mild pain when coughing during a titrated thoracic epidural infusion of about 10 ml · h^?1 of bupivacaine 1 mg · ml^?1, fentanyl 2 μg · ml^?1, and adrenaline 2 μg · ml^?1 were included. On the 1^st and 2^nd postoperative days each patient was given a double-blind epidural infusion, at the same rate, with or without adrenaline. The effect was observed for 4 h or until pain when coughing became unacceptable in spite of a rescue analgesic procedure. Rescue analgesia consisted of up to two epidural bolus injections per hour and i.v. morphine if necessary. All patients received rectal paracetamol 1 g, every 8 h. Fentanyl serum concentrations were measured with a radioimmunoassay technique at the start and end of each study period. Main outcome measures were extent of sensory blockade and pain intensity at rest and when coughing, evaluated by a visual analogue scale, a verbal categorical rating scale, the Prince Henry Hospital pain score, and an overall quality of pain relief score. Results: The number of hypaesthetic dermatomal segments decreased (P <0.001) and pain intensity at rest and when coughing increased (P <0.001) when adrenaline was omitted from the triple epidural mixture. This change started within the first hour after removing adrenaline. After 3 h pain intensity when coughing had increased to unacceptable levels in spite of rescue analgesia (epidural bolus injections and i.v. morphine). Within 15–20 min after restarting the triple epidural mixture with adrenaline, pain intensity was again reduced to mild pain when coughing. Serum concentration of fentanyl doubled from 0.22 to 0.45 ng · ml^?1 (P <0.01), and there was more sedation during the period without adrenaline. Conclusions: Adrenaline increases sensory block and improves the pain-relieving effect of a mixture of bupivacaine and fentanyl infused epidurally at a thoracic level after major thoracic or abdominal surgery. Serum fentanyl concentrations doubled and sedation increased when adrenaline was removed from the epidural infusion, indicating more rapid vascular absorption and systemic effects of fentanyl.     

Utilisation des médicaments prokinétiques en réanimation : indications et limites ?

Enteral feeding is often limited by gastric and intestinal motility disturbances in critically ill patients, particularly in patients with shock. So, promotility agents are frequently used to improve tolerance to enteral nutrition. This review summaries the pathophysiology, presents the available pharmacological strategies, the clinical data, the counter-indications and the principal limits. The clinical data are poor. No study demonstrates a positive effect on clinical outcomes. Metoclopramide and erythromycin seems to be the more effective. Considering the risk of antibiotic resistance, the first line use of erythromycin should be avoided in favor of metoclopramide.     

Anesthésie générale chez l’enfant : quid des pratiques en 2010 ?

Introduction

The practice of pediatric anesthesia requires a regular update of scientific knowledge and technical skills. To provide the most adequate Continuing Medical Education programs, it is necessary to assess the practices of pediatric anesthesiologists. Thus, the objective of this survey was to draw a picture of the current clinical practices of general anesthesia in children, in France.

Material and methods

One thousand one hundred and fifty questionnaires were given to anesthesiologists involved in pediatric cases. These questionnaires collected information on various aspects of clinical practice relative to induction, maintenance, recovery from general anaesthesia and also classical debated points such as children with Upper Respiratory Infection (URI), emergence agitation, epileptoid signs or anaesthetic management of adenoidectomy. Differences in practices between CHG (general hospital), CHU (teaching hospital), LIBERAL (private) and PSPH (semi-private) hospitals were investigated.

Results

There were 1025 questionnaires completed. Fifty-five percent of responders worked in public hospitals (CHG and CHU); 77% had a practice that was 25% or less of pediatric cases. In children from 3 to 10 years: 72% of respondents used always premedication and two thirds performed inhalation induction in more than 50% of cases. For induction, 53% used sevoflurane (SEVO) at 7 or 8%. Respondents from LIBERAL used higher SEVO concentrations. Tracheal intubation was performed with SEVO alone (37%), SEVO and propofol (55%) and SEVO with myorelaxant (8%), 93% of respondents used a bolus of opioid. For maintenance, the majority of respondents used SEVO associated with sufentanil; desflurane and remifentanil were more frequently used in CHU. Two thirds of respondents used N₂O. Depth of anesthesia was commonly assessed by hemodynamic changes (52%), end tidal concentration of halogenated (38%) or automated devices based on EEG (7%). In children with URI, 98% of respondents used SEVO for anesthesia. To control the airway 42% used a tracheal tube, 30% a laryngeal mask and 20% a facial mask. Emergence agitation was an important concern for two thirds of respondents, while epileptoid signs were considered as important by only 20%. Eighty-nine percent of respondents practiced anesthesia for adenoidectomy. Anesthesia was induced by inhalation of SEVO 7–8% (41%), 6% (39%) or 4% (12%), 66% put an intravenous line (less frequently in LIBERAL). 67% of the responders managed adenoidectomy without any device to control the airway (more frequently in LIBERAL), 32% administrated a bolus of opioid (less frequently in LIBERAL).

Discussion

This survey demonstrated that the practices regarding general anesthesia in children are relatively homogenous. Most of the differences appeared between LIBERAL and the others structures; the anaesthetic management for adenoidectomy illustrates these findings.     

Intérêt d’une rééducation précoce pour les patients neurologiques

Rehabilitation improves the functional prognosis of patients after a neurologic lesion, and tendency is to begin rehabilitation as soon as possible. This review focuses on the interest and the feasibility of very early rehabilitation, initiated from critical care units. It is necessary to precisely assess patients’ impairments and disabilities in order to define rehabilitation objectives. Valid and simple tools must support this evaluation. Rehabilitation will be directed to preventing decubitus complications and active rehabilitation. The sooner rehabilitation is started; the better functional prognosis seems to be.     

Risiko Schlaganfall — Öffentlichkeitsarbeit und Aufklärung dringend erforderlich

Zusammenfassung Das wesentliche — und zugleich noch wenig ausgeschöpfte — Potenzial der Schlaganfallmedizin liegt in der langfristigen Prophylaxe. Durch Beeinflussung von Lifestylefaktoren wie Ernährungsgewohnheiten, Zigarettenkonsum und körperlichem Training durch entsprechende Aufklärung ließe sich ein erheblicher Teil an zerebralen Ereignissen vermeiden. Ein weiterer in Deutschland noch zu wenig beachteter Faktor ist die konsequente Blutdruckeinstellung. Breitgestreute Aufklärung könnte außerdem potenziellen Patienten helfen, bereits auftretende Warnsymptome wie die transiente ischämische Attacke richtig einzuschätzen, um eine rechtzeitige Behandlung zu ermöglichen.