经伤椎椎弓根直接复位内固定治疗胸腰椎爆裂性骨折

目的探讨胸腰椎爆裂性骨折经伤椎椎弓根直接复位内固定的可行性和疗效。方法采用经伤椎结合GSS-Ⅱ型系统复位内固定治疗胸腰椎爆裂性骨折42例,术前、术后及随访时摄X线片及CT检查,观察椎体高度有无丢失,内固定有无断裂、松动。结果平均随访16个月,所有患者达到骨性融合,均得到满意的复位,矫正率达97.3%,近期内无明显矫正丢失,术后神经功能均得到不同程度的恢复。结论胸腰椎爆裂性骨折应用伤椎椎弓根螺钉可以增强内固定系统的牢固性,并有利于矫正后凸畸形和维持矫正效果。     

椎弓根螺钉内固定结合椎体成形术治疗老年胸腰椎爆裂性骨折

目的:探讨椎弓根内螺钉固定结合椎体成形术治疗老年胸腰椎爆裂性骨折的可行性并评估其疗效。方法:采用短节段椎弓根螺钉内固定结合经椎弓根伤椎内注射骨水泥治疗60岁以上老年胸腰椎爆裂性骨折患者23例,术后观察骨折椎体前后缘压缩率变化、Cobb角改善情况及并发症。结果:术后随访12￣40个月(平均24.2个月)。骨折椎体前后缘均恢复满意,术前椎体前、后缘压缩率分别为(52.76±5.07)%和(18.12±2.29)%,术后椎体前后缘压缩率分别为(8.09±0.83)%和(0.99±0.22)%,术后与术前比较差异均有统计学意义(P<0.01);矢状位Cobb角由术前平均17.0°矫正至5.1°,平均矫正10.9°,无术后并发症,平均下地时间为18d。10例脊髓神经损伤患者,术后按美国脊髓损伤协会(ASIA)标准恢复1级及以上,无1例脊髓神经损伤加重者。椎体高度无明显丢失,无椎间隙塌陷,无内固定断裂或弯曲、松动。结论:后路椎弓根螺钉内固定结合椎体成形术,能同时恢复椎体高度及强度,重建脊柱的稳定性,使患者早期下地活动,可减少内固定应力过大造成的断钉、椎体高度丢失等并发症,是治疗老年胸腰椎爆裂性骨折的有效方法。     

经伤椎椎弓根植骨联合后路椎弓根内固定治疗胸腰椎稳定型爆裂性骨折

目的探讨经骨折椎椎弓根植骨联合椎弓根内固定治疗胸腰椎稳定型爆裂性骨折的方法和效果。方法对17例胸腰椎稳定型爆裂性骨折的患者行经骨折椎椎弓根植骨及椎弓根内固定术,术前、术后及随访时测量椎体高度、后凸角,了解神经功能改变及腰背疼痛变化。结果随访8～37个月,无断钉及内固定物松动,椎体高度和后凸角无明显再丢失,神经功能及腰背疼痛明显改善。结论经骨折椎椎弓根植骨联合后路椎弓根内固定治疗胸腰椎稳定型爆裂性骨折可重建脊柱前中柱的稳定性,防止后期矫正角度及椎体高度的再丢失。     

经椎弓根植骨治疗胸腰椎爆裂骨折

目的评估经椎弓根植骨在治疗胸腰椎爆裂性骨折中的作用。方法胸腰椎爆裂性骨折32例,采用后路短节段椎弓根复位内固定后,取自体髂骨剪成碎沫状,经伤椎椎弓根植入伤椎椎体内。术前、术后及随访期间拍摄胸腰椎X线片,测量伤椎高度与正常高度的比值、脊柱后凸Cobb角,对测量数据作统计学分析。结果术后伤椎中央高度、脊柱后凸Cobb角得到明显恢复,未发生内置物断裂和螺钉松动现象,随访期间无明显矫正度丢失。结论经伤椎椎弓根椎体内植骨是一种防止内固定失败和矫正度丢失的有效方法。     

AF椎弓根钉系统治疗胸腰椎爆裂性骨折46例

目的探讨AF椎弓根钉内固定系统治疗胸腰椎爆裂性骨折的疗效。方法应用AF经椎弓根钉内固定系统治疗胸腰椎爆裂性骨折46例。结果平均随访11个月。46例椎体前缘高度由术前平均25％恢复至平均95％。椎管内移位骨块复位率达90％。神经损伤的恢复按ASIA分级：A级中19例无变化，余27例均提高1～2级。结论AF椎弓根钉内固定系统能达到满意复位固定及椎管有效减压，是一种治疗胸腰椎爆裂性骨折理想的方法。     

经伤椎椎弓根钉固定治疗胸腰椎爆裂性骨折

目的探讨经伤椎椎弓根钉固定治疗胸腰椎爆裂性骨折的可行性及临床疗效。方法经伤椎椎弓根钉固定治疗23例胸腰椎单节段爆裂性骨折患者。结果患者均获随访,时间6～18（12±3.1）个月。骨折椎体均愈合,愈合时间3～6个月,伤椎置入椎弓根钉无神经损伤,术后伤椎高度较术前得到明显恢复,后凸畸形角度明显改善,生理弧度恢复。末次随访时伤椎高度丢失不明显。结论采用经伤椎椎弓根螺钉短节段固定是一种维持胸腰椎爆裂性骨折复位的有效方法。     

经椎弓根植骨治疗胸腰椎爆裂骨折的对照研究

目的探讨经伤椎椎弓根椎体植骨在胸腰椎爆裂骨折中的作用和疗效。方法采用经伤椎椎弓根椎体植骨，GSS-Ⅱ型系统复位、内固定治疗胸腰椎爆裂骨折22例，并与前期（2004年前）及同期未行椎弓根植骨的胸腰椎爆裂骨折26例作对照研究。术前、术后及随访时行X线及CT检查，观察椎体高度及矫正Cobb角有无丢失，内固定有无断裂、松动情况发生。结果治疗组全部病例获得随访，无一例发生内固定断裂、松动，治疗组与对照组在远期椎体高度丢失率、矫正后凸Cobb角丢失度方面有显著性差异。结论胸腰椎爆裂骨折经伤椎椎弓根椎体植骨、GSS一1型内固定后，可恢复伤椎椎体高度，重建前中柱的稳定性，防止术后远期椎体高度和矫正Cobb角的再丢失以及内固定的松动、断裂。     

后路椎弓根钉内固定结合椎弓根植骨治疗胸腰椎爆裂性骨折的临床疗效观察

[目的]探讨后路椎弓根钉内固定结合椎弓根植骨治疗胸腰椎爆裂性骨折的方法和疗效。[方法]对56例胸腰椎爆裂性骨折患者行后路椎弓根钉内固定并椎弓根植骨,术前、术后及随访时测量椎体前后缘高度、Cobb后凸角,观察腰背部疼痛、胸腰段活动度、终板完整性及神经功能的变化。[结果]随访24~60个月,椎体高度无明显丢失,后凸畸形无加重,无椎间隙塌陷,无内固定物松动、断裂和游离,终板结构完整,胸腰段活动度好。[结论]后路椎弓根钉内固定结合椎弓根植骨治疗胸腰椎爆裂性骨折能重建脊柱前中柱稳定性,防止远期椎体高度及矫正角度的再丢失,维持脊柱的整体生物力学平衡。     

经后路椎体次全切除后钛网支撑置入加椎弓根钉内固定治疗腰椎爆裂性骨折的初步报告

目的 探讨经后路椎体次全切除、钛网支撑植入加椎弓根钉内固定治疗腰椎爆裂性骨折的可行性及临床价值. 方法 2009年1月至6月对3例腰椎爆裂性骨折患者采用经后路椎体次全切除、钛网支撑植入加椎弓根钉内固定治疗,其中男2例,女1例;平均年龄49.3岁;骨折部位均为L2.术前神经功能采用美国脊髓损伤协会(ASIA)分级:C级1例,D级2例. 结果 术后1周X线片示伤椎椎体前缘高度由术前的平均(20.0±2.7)mm恢复至(37.0±0.5)mm,占上下椎体平均高度由术前平均54.0%±0.5%提高至98.5%±0.5%;Cobb角由术前平均32.0°±2.0°矫正至2.5°±0.6°.2例钛网位置良好,1例钛网位置少许偏斜.随访4～7个月,平均6个月.ASIA神经功能分级均有1级的恢复,双下肢、腰部活动及外观良好.未次随访时X线片示复位效果满意,脊柱序列恢复正常,Cobb角和椎体前缘高度无丢失,钛网未见移位,钛网周围见大量骨痂形成.结论 对于腰椎爆裂性骨折患者,应用经后路椎体次全切除、钛网支撑置入加椎弓根钉内固定术,能够一次完成固定、减压、复位、融合,并且可重建三柱的稳定性.     

后路椎弓根螺钉固定及经椎弓根植骨治疗胸腰段脊柱爆裂性骨折

目的探讨后路椎弓根螺钉固定及经椎弓根植骨治疗胸腰段脊柱爆裂性骨折的治疗效果。方法采用后路椎弓根螺钉固定及经椎弓根植骨治疗24例胸腰段脊柱爆裂性骨折的患者。分析术前、术后神经功能恢复情况,伤椎椎体高度变化、Cobb’S角、椎管占位情况比及腰背部疼痛情况。结果所有手术均顺利完成,随访术后12～24个月,未发现断钉及内固定物松动,椎体高度和后凸角无明显再丢失,术前和术后Cobb’S角、椎体前缘高度、椎体平移率、VAS的比较差异有统计学意义（P〈0．05）。结论后路椎弓根螺钉固定及经椎弓根植骨治疗胸腰段脊柱爆裂性骨折操作简单、安全可靠,不增加软组织刨伤,并发症少,并且能获得更好的骨折复位以及避免后期椎体高度丢失。     

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.     

A comparison of the inhibitory effects of four volatile anaesthetics on the metabolism of chlorzoxazone, a substrate for CYP2E1, in rabbits

Background: Halothane inhibits in vitro and in vivo activity of cytochrome P-450 (CYP) 2E1. There are several fluorinated volatile anaesthetics besides halothane, and most of them are defluorinated by CYP2E1. It is unclear whether other fluorinated anaesthetics inhibit the in vivo activity of CYP2E1.
Methods: We compared the inhibitory effects of therapeutic concentrations of four inhalational anaesthetics, halothane, enflurane, isoflurane, and sevoflurane, on chlorzoxazone metabolism in rabbits receiving artificial ventilation.
Results: All four inhalational anaesthetics decreased arterial blood pressure and increased plasma chlorzoxazone concentration. However, no significant differences in the plasma chlorzoxazone concentration were found between the four anaesthetics. The estimated chlorzoxazone clearance increased after beginning inhalation with all four agents, but no significant difference in clearance was noted between agents.
Conclusions: At therapeutic concentrations, the in vivo inhibitory effect on chlorzoxazone metabolism was similar for all four inhalational anaesthetics examined, even though their chemical characteristics and extent of hepatic metabolism differ considerably.     

A Teaspoon Pump for Pumping Blood with High Hydraulic Efficiency and Low Hemolysis Potential

Abstract: Virtually all blood pumps contain some kind of rubbing, sliding, closely moving machinery surfaces that are exposed to the blood being pumped. These valves, internal bearings, magnetic bearing position sensors, and shaft seals cause most of the problems with blood pumps. The original teaspoon pump design prevented the rubbing, sliding machinery surfaces from contacting the blood. However, the hydraulic efficiency was low because the blood was able to "slip around" the rotating impeller so that the blood itself never rotated fast enough to develop adequate pressure. An improved teaspoon blood pump has been designed and tested and has shown acceptable hydraulic performance and low hemolysis potential. The new pump uses a nonrotating "swinging" hose as the pump impeller. The fluid enters the pump through the center of the swinging hose; therefore, there can be no fluid slip between the revolving blood and the revolving impeller. The new pump uses an impeller that is comparable to a flexible garden hose. If the free end of the hose were swung around in a circle like half of a jump rope, the fluid inside the hose would rotate and develop pressure even though the hose impeller itself did not "rotate"; therefore, no rotating shaft seal or internal bearings are required.     

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.     

Tissue perfusion in relation to cardiac output during continuous positive-pressure ventilation and administration of propranolol or verapamil

Background : Our objective was to determine whether administration of propranolol or verapamil modifies the hemodynamic adaptation to continuous positive-pressure ventilation (CPPV), in particular the regional distribution of cardiac output (CO).
Methods : General hemodynamics and regional blood flows assessed by microsphere technique (15 (μm) were recorded in 16 anesthetized pigs during spontaneous breathing (SB) and CPPV with 8 cm H₂O end-expiratory pressure (CPPV8) before and after intravenous administration of propranolol (0.3 mg · kg⁻¹ followed by 0.15 mg · kg⁻¹ · h⁻¹, n=8) or verapamil (0.1 mg · kg⁻¹ followed by 0.3 mg · kg⁻¹ · h⁻¹, n=8).
Results : CPPV8 depressed CO by 25% without shifts in its relative distribution with the exception of a noteworthy increase in adrenal perfusion. Propranolol increased arterial blood pressure, and due to a fall in heart rate, CO dropped by 25%. The kidneys and, to a lesser extent, the splanchic region and central nervous system received increased fractions of the remaining CO at the expense of skeletal muscle flow. Similar patterns were seen during SB and CPPV8 such that the combination of propranolol and CPPV8 depressed CO by 50%. The circulatory effects of verapamil were less evident but myocardial perfusion tended to increase.
Conclusions : The combination of propranolol or verapamil with CPPV does not result in any specific hemodynamic interaction in anesthetized pigs, except that the combined effect of propranolol and CPPV may severely reduce CO.     

Volatile anaesthetics reduce adhesion of blood platelets under low-flow conditions in the coronary system of isolated guinea pig hearts

Background : Inhibitory effects of volatile anaesthetics on platelet aggregation have been demonstrated in several studies. However, the influence of volatile anaesthetics on intracoronary platelet adhesion has not been elucidated so far.
Methods : Isolated hearts of guinea pigs were perfused with buffer in the absence or presence of volatile anaesthetics (0.5 and 1 MAC) at constant coronary flow rates of 5 ml/min for 25 min, then 1 ml/min for 30 min and again 5 ml/min for 10 min. Before, during and after low-flow perfusion, a bolus of human platelets was applied into the coronary system. To simulate thrombogenic conditions, 0.3 U/ml human thrombin was infused during low-flow perfusion and reperfusion. The number of platelets sequestered to the endothelium was calculated from the difference between coronary in- and output of platelets. The myocardial production of lactate and consumption of pyruvate and coronary perfusion pressure were also determined.
Results : At a flow rate of 5 ml/min only about 3% of the applied platelets did not emerge from the coronary system, in any group. In contrast, 13.1±1.2% (mean±SEM) of infused platelets became adherent in low-flow perfusion in the control group without anaesthetic. The adherence was reduced with each 1 MAC isoflurane (to 6.2±1.2%), sevoflurane (to 4.4±0.9%) or halothane (to 3.2±1.5%) (each P <0.05 vs. control). Volatile anaesthetic, 0.5 MAC, did not inhibit platelet adhesion to a statistically significant extent in any case. Perfusion pressure and metabolic parameters were not statistically different between the control and the hearts exposed to anaesthetics.
Conclusion : Volatile anaesthetics in a concentration of 1 MAC can reduce the adhesion of platelets in the coronary system under reduced flow conditions. This action does not arise from vasodilation or inhibition of ischaemic stress.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

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.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.