改良钉棒系统治疗垂直不稳定骨盆骨折的生物力学研究

目的 探讨改良钉棒系统治疗垂直不稳定型骨盆骨折,并分析其生物力学性质.方法 在8例尸体骨盆标本上造模成垂直不稳定型骨盆骨折,分别行TOS术式固定、骶髂螺钉固定、改良钉棒系统固定,检测1000 N载荷下骨盆刚度、骨折分离移位距离及局部应变改变.结果 骨盆标本骨折模型采用各种不同固定方式,经生物力学测试,改良钉棒系统在载荷1000 N下刚度(224.3±18.3)N/mm及骨折分离移位距离(1.98±0.24)mm,明显优于骶髂螺钉固定(169.10±17.60)、(8.08±0.71)mm,差异有统计学意义(P＜0.01),与TOS(233.20±12.90)、(1.62±0.31)mm比较,差异无统计学意义(P＞0.05).结论 改良钉棒系统是一种生物力学性能较好的治疗垂直不稳定型骨盆骨折的新方法.     

手术治疗耻骨联合分离合并耻骨上下枝骨折1例报告

骨盆骨折多由于直接暴力所造成的。侧方挤压损伤多局限于耻骨支和耻骨联合处,骨盆骨折传统的治疗手段是骨盆帆布兜悬吊或骨盆兜夹扳固定,卧床需6～8周即可,传统的治疗方法对骨盆环完整性效果较好。本例骨盆骨折为一例耻骨上枝骨折另一侧耻骨上下支骨折合并耻骨联合分离旋转移位,保守治疗很难     

Colorado 2TM骶髂板治疗Tile C型骨盆骨折中骶髂关节骨折脱位的临床研究

目的探讨Colorado 2TM骶髂板在治疗Tile C型骨盆骨折中对骶髂关节骨折脱位稳定性重建的作用。方法 2009年2月-2011年1月,收治8例Tile C型骨盆骨折患者。男3例,女5例;年龄22～52岁,平均34.4岁。交通事故伤3例,高处坠落伤3例,重物挤压伤2例。按照Tile分型,C1-2型5例,C1-3型2例,C2型1例。受伤至手术时间5～10 d,平均7 d。经股骨髁上牵引,使骶髂关节骨折脱位复位后,采用Colorado 2TM骶髂板固定骶髂关节,选择性加用骨盆前环重建钢板或外固定支架固定。结果术后X线片复查示骶髂关节垂直和旋转移位均获满意复位,骶髂关节得到有效固定,骨盆后环获得即刻稳定性。术后切口均Ⅰ期愈合,未发生血管、神经损伤等严重并发症。8例均获随访,随访时间6～24个月,平均12个月。骶髂关节无再移位,螺钉无松动。骨折愈合时间6～12个月,平均9个月。末次随访时采用Majeed功能评价标准,获优5例,良2例,一般1例。结论 Colorado 2TM骶髂板固定可使骨盆后环获得有效的即刻稳定性并维持至骨折愈合,是治疗Tile C型骨盆骨折中骶髂关节骨折脱位的有效方法之一。     

Colorado 2~(TM)骶髂板治疗Tile C型骨盆骨折中骶髂关节骨折脱位的临床研究

目的探讨Colorado 2TM骶髂板在治疗Tile C型骨盆骨折中对骶髂关节骨折脱位稳定性重建的作用。方法 2009年2月-2011年1月,收治8例Tile C型骨盆骨折患者。男3例,女5例;年龄22～52岁,平均34.4岁。交通事故伤3例,高处坠落伤3例,重物挤压伤2例。按照Tile分型,C1-2型5例,C1-3型2例,C2型1例。受伤至手术时间5～10 d,平均7 d。经股骨髁上牵引,使骶髂关节骨折脱位复位后,采用Colorado 2TM骶髂板固定骶髂关节,选择性加用骨盆前环重建钢板或外固定支架固定。结果术后X线片复查示骶髂关节垂直和旋转移位均获满意复位,骶髂关节得到有效固定,骨盆后环获得即刻稳定性。术后切口均Ⅰ期愈合,未发生血管、神经损伤等严重并发症。8例均获随访,随访时间6～24个月,平均12个月。骶髂关节无再移位,螺钉无松动。骨折愈合时间6～12个月,平均9个月。末次随访时采用Majeed功能评价标准,获优5例,良2例,一般1例。结论 Colorado 2TM骶髂板固定可使骨盆后环获得有效的即刻稳定性并维持至骨折愈合,是治疗Tile C型骨盆骨折中骶髂关节骨折脱位的有效方法之一。     

重建钢板治疗C型骨盆骨折

C型骨盆骨折具有垂直和旋转不稳定性，重建后环需良好复位稳固内固定，对前环是否需要切开复位内固定尚存有争议。随内固定材料的改进，骨盆生物力学、解剖学及影像学研究的深化，骨盆前、后环骨折脱位临床内固定方式选择增多，不稳定的骨盆环治疗中骨盆前、后环手术重建非常重要。本院从2004年9月至2007年9月25例C型骨盆骨折行前、后环重建钢板内固定，效果满意，报告如下。     

开书型骨盆骨折与男性尿道损伤关系的实验研究

目的对骨盆骨折模型尿道行CT扫描,探讨耻骨联合分离和后尿道损伤的关系。方法于男性骨盆标本尿道内置入造影剂,制成开书型骨折模型,CT扫描测定尿道和骨盆壁的关系。结果耻骨联合分离6cm时,尿道前列腺、尖部与完整侧耻骨联合后缘的距离从(2.03±0.27)cm分离到(2.95±0.31)cm,伴有尿道向完整侧半骨盆移位。结论骨盆骨折尿道损伤多发生于前列腺尖部,骨折时尿道前列腺尖部、前列腺部及膜部均向尾侧和健侧移位。     

垂直不稳定骨盆骨折内固定垂直稳定性的生物力学研究

目的探讨垂直不稳定骨盆骨折空心螺钉和钢板内固定前后环或后环的垂直方向稳定性差异。方法：将6具尸体骨盆随机取3具做压力测试为正常组，然后制成垂直不稳定骨盆骨折模型，分别行后环空心螺钉结合前环空心钉、后环空心螺钉、后环结合前环钢板、后环钢板内固定。结果在垂直方向，后环空心螺钉内固定强于钢板螺丝钉内固定，增加前环内固定可以显著增加前环的稳定性。结论垂直不稳定骨盆骨折空心螺钉内固定具有较好的生物力学稳定性，前后环内固定要优于单纯后环内固定。     

骨盆新月形骨折的研究进展

骨盆新月形骨折是Young-Burgess骨盆骨折分型中侧方挤压型Ⅱ型中典型的后环损伤表现。近年来许多学者就其受伤机制、影像学表现、分型、骨盆稳定性及手术方式提出了一些新的观点。微创复位经皮螺钉内固定在骨盆新月形骨折的治疗中应用越来越广泛。本文就骨盆新月形骨折的临床特征、分型、治疗等方面作一综述,以期使读者对骨盆新月形骨折有一个更加全面的认识,从而选择更合理的治疗方式。     

应用外固定器治疗侧方挤压损伤型骨盆骨折

目的探讨闭合复位外固定器固定治疗侧方挤压损伤型骨盆骨折的效果。方法采用闭合复位,两侧髂嵴各穿放2枚固定针,外固定器挤压固定,早期负重功能康复训练(平均术后14d扶拐下地部分负重行走)。结果所有病例骨盆两侧均获得对称性复位。平均愈合时间8·6周(7~14周)。平均随访4年(3~7年),初始复位后无明显的骨折再分离移位。结论外固定器是一种有效的治疗侧方挤压损伤型骨盆骨折的微创方法。     

骨盆外固定支架治疗骨盆骨折

目的: 探讨用外固定架治疗不稳定型骨盆骨折的可行性、特点及具体方法。方法: 根据骨盆骨折稳定性的Tile创伤分类, 对不同的创伤类型应用相对应的作用力进行固定,达到消除骨盆骨折移位、稳定骨盆环的目的。结果: 本组 13例, 1例未随访, 12例获得平均 23. 4个月随访, 7例均获得骨性愈合, 恢复原有工作, 3例良好, 2例可, 总优良率为 83. 3%。结论: 外固定术具有创伤小, 操作简单, 不增加损伤等优点。对于骨盆后侧韧带保持完整的B型骨折, 由于外固定架与后韧带群的协同作用, 因而能形成可靠固定。对同时存在垂直不稳定型的骨盆骨折, 骨外固定术可稳定骨折块, 减少出血, 从而有利于稳定血流动力学, 为早期复苏赢得时间。骨盆外固定支架是治疗B型骨盆骨折的一种较好的方法。     

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 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.     

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.     

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.     

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.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.