枕寰枢后路经关节螺钉内固定的可行性研究

目的明确后路寰枕关节经关节螺钉固定的螺钉、进钉点植入角度、钉道角度和螺钉长度。探讨枕颈部经关节螺钉内固定技术的手术指征效果和并发症。方法在 2 0例含有完整寰枕关节的干燥骨性标本上 ,直视下进行后路寰枕关节经关节克氏针植入 ,在头尾侧和侧位X线片上测量理想的钉道角度和钉道长度。 30例正常成年人的寰枕关节进行三维CT重建 ,同时测量后路寰椎关节经关节螺钉钉道角度的可调范围。 12例新鲜枕颈部标本进行后路枕颈部关节螺钉内固定 ,术后行正、侧位X线片和三维CT重建 ,以验证螺钉位置。结果干燥标本模拟X线片测量 ,寰枕关节螺钉的钉道在矢状面上呈上倾 ,在冠状面上呈内倾 ,钉道的理想角度为 :在矢状面上倾角为 5 3.3°± 3.4° ,在冠状面内倾角为 2 0 .0°± 2 .6°。螺钉钉道长度为 (2 9.2 8± 2 .4 6 )mm。依据三维CT重建后测量 ,钉道方向与矢状面上倾角存在一个可调范围 ,一般为 4 9.6°± 2 .0°,与冠状面的内倾角也存在一个可调范围 ,一般为 4 0 .4°± 3.4°。齿突与枕髁前方最高点间距为 9.80～ 17.7mm ,平均 (13.4 3± 1.93)mm。寰枕关节关节螺钉内固定 ,影像学检查显示 ,螺钉钉道均经过寰枕关节 ,未进入神经管。结论寰枕关节后路经关节螺钉植入存在一定的方向性 ,钉道长度和钉道角度     

寰枕关节后路经关节螺钉固定钉道参数的测定

目的 明确后路寰枕关节经关节螺钉固定的技术参数;探讨枕颈部经关节螺钉内固定技术的临床意义。方法 30例含完整寰枕关节干燥骨性标本,直视下行后路寰枕关节经关节克氏针植入后行X线摄片,在X线胶片上测量寰枕关节经关节螺钉固定的钉道角度和钉道长度。结果 寰枕关节经关节螺钉固定的钉道理想角度为:螺钉方向在矢状面的上倾角为 53. 3°±3. 4°,在冠状面的内倾角为 20. 0°±2. 6°。钉道长度为: (29. 28±2. 46)mm。结论 寰枕关节后路经关节螺钉植入存在一定的方向性和钉道长度问题,结合后路C1, 2经关节螺钉内固定后可视为能满足当前临床需要的一种相对理想的枕颈融合内固定术式。     

后路经寰枕关节螺钉固定钉道的测定

目的:明确后路寰枕关节经关节螺钉固定的技术参数;探讨枕颈部经关节螺钉内固定技术的临床意义。方法:30例含完整寰枕关节干燥骨性标本,直视下行后路寰枕关节经关节克氏针植入后行X线摄片,在X线片上测量寰枕关节经关节螺钉固定的钉道角度和长度。结果:寰枕关节经关节螺钉固定的钉道理想角度为:螺钉方向在矢状面的上倾角为(53.3±3.4)°,在冠状面的内倾角为(20.0±2.6)°。钉道长度为(29.28±2.46)mm。结论:寰枕关节后路经关节螺钉植入存在一定的方向性和钉道长度,结合后路C1-C2经关节螺钉内固定后可视为能满足当前临床需要的一种相对理想的枕颈融合内固定术式。     

前路经枢椎体至寰椎侧块螺钉内固定的解剖学基础

目的 为临床行前路枢椎体至寰椎侧块螺钉固定方法提供实验依据。方法 用游标卡尺测量21例(42侧)C1和C2成人骨标本,计算出前路经枢椎体至寰椎侧块 螺钉内固定术中螺钉走向的最小、最大外偏角和最大后倾角。结果在前路经枢椎体 至寰椎侧块螺钉内固定术中螺钉的最小外偏角为14°±1．6°,最大外偏角为30°±2．3°, 最大后倾角为29°±2．9°,左、右侧无明显统计学差异(P>0．05)。结论 前路经枢椎体至 寰椎侧块螺钉内固定是安全可行的。     

前路经枕寰枢关节螺钉内固定的临床解剖学研究

[目的]探讨前路经枕寰枢关节螺钉的临床应用解剖学依据。[方法]取30具国人干燥枕颈部标本,测量与经枕寰枢关节螺钉内固定术相关的解剖径线及钉道参数;并以此类数据为依据,在所测量的干燥标本上模拟行经枕寰枢关节螺钉内固定术,经X线摄片检查内固定位置并测量钉道实际角度。[结果]前路经枕寰枢关节螺钉内固定的钉道在矢状面上呈后倾,在冠状面上呈外倾。左右两侧钉道角度大小差异无统计学差异,理想外倾角为(18.15±3.70)°,理想后倾角为(24.20±4.91)°,理想钉道长度为(34.45±2.9)mm;模拟行内固定验证,术后影像学及直视下检查结果显示,螺钉钉道均经过枕寰枢关节,角度均在此范围内,无穿出骨质者。[结论]采用前路经枕寰枢关节螺钉行枕颈融合内固定在解剖上是可行的。     

前路经寰枢外侧关节螺钉内固定术的生物力学评价

目的：评价不同方法前路经寰枢外侧关节螺钉内固定的稳定性和刚度。方法：通过体外生物力学实验，对15例新鲜尸体标本的正常、齿状突切除、三种不同有路经寰枢外侧关节螺钉内固定术、后路Brooks法寰枢关节内固定术等状态进行三维角度运动范围和关节刚度进行测试。结果：前路经寰枢外侧关节螺钉内固定术明显减少寰枢关节的各向角度运动范围；三种不同方法之间寰枢关节的各向角度运动范围和刚度无明显差异；前路经寰枢外侧关节螺钉内固定术较后路Brooks法内固定术，寰枢关节的旋转和侧屈运动范围减少更明显，寰枢关节的由前向后剪切和旋转刚度更高。结论：前路经寰枢外侧关节螺钉内固定术的稳定性和刚度达到了临床治疗的要求，术后对外固定强度的依赖较低，三种不同方法的生物力学结果相近，为简化操作和设计提供了新思路。     

前路经寰枢关节螺钉内固定三维稳定性的实验研究

目的：评价前路经寰枢关节螺钉内固定术治疗寰枢椎不稳定的三维稳定性。方法：8具新鲜颈椎标本，对每一标本分别测定正常状态、齿状突Ⅱ型骨折、前路经寰枢关节螺钉内固定术、后路Maged螺钉内固定术4种状态下的三维运动范围。结果：前路经寰枢关节螺钉内固定术与后路Magerl螺钉内固定术均能明显减少寰枢关节各方向运动范围，经统计学检验两种固定方法无显著性差异（P〉0．05）。结论：前路经寰枢关节螺钉内固定术的三维稳定性与后路Maged螺钉内固定术相当，为寰枢椎不稳定患者的治疗提供了另一种选择。     

前路经寰枢关节锁定钛板螺钉内固定系统三维稳定性的实验研究

[目的]评价前路经寰枢关节锁定钛板螺钉内固定系统治疗寰枢椎不稳的三维稳定性。[方法]8例颈椎新鲜标本,对每一标本分别测定完整状态、齿状突Ⅱ型骨折、前路经寰枢关节锁定钛板螺钉内固定和后路椎弓根螺钉内固定的三维运动范围,并对结果进行统计学分析。[结果]前路固定的前屈为(1.39±0.26)°,后伸为(1.40±0.22)°,侧屈为(1.43±0.23)°,旋转为(1.77±0.34)°。后路固定的前屈为(1.37±0.23)°,后伸为(1.39±0.20)°,侧屈为(1.41±0.22)°,旋转为(1.77±0.33)°,前路经寰枢关节锁定钛板螺钉固定和后路椎弓根螺钉固定的寰枢椎三维运动范围无显著统计学差异(前屈P=0.930,后伸P=0.952,左右侧屈P=0.947,左右旋转P=0.950)。[结论]前路经寰枢关节锁定钛板螺钉固定术的三维稳定性与后路椎弓根螺钉固定术相当,为寰枢椎不稳患者提供了一种手术治疗选择。     

前路经枕-寰-枢关节螺钉内固定力学的三维有限元分析

[目的]建立前路经枕-寰-枢关节螺钉内固定的三维有限元模型,并对其进行生物力学分析.[方法]采集1名健康成年男性CT图像,建立枕骨髁(C0)-C2的三维有限元模型,并验证其有效性.在此模型上通过单元结构的删减建立枕颈部不稳定模型,植入前路经枕-寰-枢关节螺钓‘行枕颈固定.对术后模型进行自由度约束,在其表面分别施加前屈、后伸、侧屈、旋转方向上的生理载荷.计算并分析螺钉各部的应力、应变情况.[结果] 前路经枕-寰-枢关节螺钉在前屈、后伸方向载荷下的位移峰值、应力峰值,明显高于侧屈、旋转.在不同方向载荷下前路经枕-寰-枢关节螺钉的应力峰值均出现于螺钉通过寰枢关节区域.[结论]前路经枕-寰-枢关节螺钉内固定在抗侧屈、旋转上具有良好的力学性能,但在抗前屈、后伸方面力学性能较差,螺钉在通过寰枢关节处为应力集中最明显的区域,易产生固定疲劳.     

前路经寰枢关节螺钉内固定行枕颈融合的解剖学研究

目的：寻求前路经寰枢关节螺钉内同定行枕颈融合可行性的解剖学依据。方法：对30例正常国人行枕寰枢区三维CT重建，测量与内同定有关的解剖径线长度及角度大小，观察舌下神经管与枕骨髁的相对位置关系：并以测得的数据为依据在8具人体干燥枕寰枢标本上行螺钉内固定，三维CT检查内固定位置。结果：枕骨髁关节面的宽度为11．23～17．08mm，后1／3宽度为3．74～5．69mm，寰椎上关节面的长度为11．65～20．71mm，枕骨髁高度为4130～10．62mm，舌下神经管的位置相对恒定，表明枕颈部解剖结构适于行前路枕颈融合术；内同定后三维CT检查未见毗邻组织损伤。结论：前路经寰枢关节螺钉内同定行枕颈融合在解剖上是可行的，舌下神经管与枕骨髁的位置关系相对恒定，但少部分舌下神经管位于枕骨髁的后外侧，会使进针变得危险。     

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.     

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.     

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.