钽棒植入联合带血管蒂髂骨瓣转移治疗中青年早期股骨头坏死

目的探讨钽棒植入联合带血管蒂髂骨瓣转移治疗中青年早期股骨头坏死的临床疗效。方法回顾性分析2007年10月至2012年1月中山大学附属江门医院采用钽棒植入联合带血管蒂髂骨瓣转移治疗的11例（15髋）中青年早期股骨头坏死患者的临床资料,记录手术时间、术中出血量,观察内置钽棒松动、断裂及症状改善情况,末次随访时进行髋关节Harris评分和影像学检查。结果11例患者随访12~60个月（平均24个月）。手术时间60～100min（平均70min）、术中出血量200~400mL（平均280mL）。随访期间内置钽棒未见松动、断裂,未出现钽棒排斥反应。患髋疼痛感减轻或消失,末次随访时Harris评分为（85士4）分,较术前的（62士3）分明显提高（f=6．505,P=O．000）。影像学检查未见股骨头塌陷,植骨区域未出现骨坏死趋势。结论钽棒植入联合带血管蒂髂骨瓣转移手术可改善血供,提供足够的力学支持,有效防止股骨头进一步塌陷,临床功能改善效果较理想,是治疗中青年早期股骨头坏死的有效方法。     

髓芯减压钽棒植入治疗早期股骨头坏死的近期疗效

目的探讨髓芯减压加钽棒植入治疗早期股骨头坏死的近期临床效果。方法对15例早期股骨头坏死患者实施髓芯减压及钽棒植入治疗术,术后平均随访10个月,依据Harris髋关节评分系统对术前及术后髋关节功能进行评价。结果Harris评分由术前(68.32±5.13)分增加到(90.12±6.69)分,优良率为93.33%。影像学检查结果提示全部患者股骨头坏死区无1例进展及塌陷。结论髓心减压联合钽棒植入术治疗早期股骨头坏死近期疗效满意,具有创伤小、术后恢复快、操作简单、并发症少等优点。     

钽棒支撑用于股骨头坏死研究概况

股骨头坏死存在众多病因学说,针对不同学说和疾病不同分期而有多种治疗方法。钽棒支撑技术是近年开始应用的一项针对股骨头坏死的微创手术治疗手段,治疗原理是在坏死股骨头髓芯减压基础上以多孔钽金属棒为股骨头及软骨下骨板提供安全而有效的力学支撑,并促进新生骨与血管的长入。此技术操作简单,在透视引导下准确定位髓芯钉道后逐步扩髓、测深、攻丝并植入合适规格的钽棒。基础试验研究表明,多孔钽棒植入物在结构和生理力学特性上十分接近天然骨组织,且组织相容性和安全性好。临床试验研究发现,钽棒支撑能改善早期无塌陷股骨头坏死患者的髋关节功能,并有效阻止坏死加重;对中晚期患者的治疗效果则尚不肯定。钽棒支撑为无塌陷早期股骨头坏死患者提供了一种新的治疗方法。     

钽棒治疗早期非创伤性股骨头坏死的回归性研究

[目的]分析钽棒治疗早期股骨头坏死的临床疗效,探讨影响钽棒治疗早期股骨头坏死临床疗效的因素.[方法]钽棒治疗早期股骨头坏死病例149例(168髋),男96例,女53例;平均年龄32.36岁.Ⅰ期和Ⅱ期(塌陷前)88髋,Ⅲ期(塌陷后)80髋,其中双侧19例.根据ARCO分期,进行Harris评分和影像学评估.将Harris评分70分以下、再次手术、影像学病变进展(股骨头由非塌陷变塌陷或塌陷加重,关节间隙狭窄加重)视为钽棒失败.[结果]共随访到130例138髋,平均随访时间(31.47±5.78)(8～61)个月,术前平均Harris评分为62.65,术后为79.50(P<0.05).优良率为68.12%.Cox风险模型分析显示大病灶、外侧病灶、植骨与否是手术失败的风险因素,病因、性别、年龄、病灶是否在股骨头骺板内,对钽棒治疗早期股骨头坏死的临床疗效无明显影响.[结论]影响钽棒治疗早期股骨头坏死临床疗效的因素是病灶大小(大于30%)、坏死灶位置(外侧型)、植骨与否,钽棒治疗早期股骨头坏死需要清除死骨、联合植骨.     

多孔钽金属棒治疗股骨头坏死的最新研究进展

股骨头坏死是由多种病因引起的一种进行性疾病,因股骨头血供的破坏,导致骨细胞的坏死和关节表面塌陷。如不进行治疗,约70%~80%的患者会逐渐发展到骨关节炎而不得不进行全髋关节置换。因此,对于股骨头坏死的早期干预是保护髋关节的关键。多孔钽金属棒植入是近几年兴起的治疗早期股骨头坏死的新方法,以其手术过程简单、手术时间短、安全性高、并发症少、临床疗效优良等特点在国内外有着广泛运用。近几年关于钽棒的失败案例时有报道,以钽金属棒为基础的联合手术方法也开始逐渐出现。本文回顾分析相关文献,就多孔钽金属棒治疗股骨头坏死的最新研究进展作一简要综述。     

高速旋切刀在髓芯减压钽棒置入术中的临床应用

目的探讨高速旋切刀在髓芯减压钽棒术中置入坏死骨组织中的临床应用。方法应用高速旋切刀在进行髓芯减压。彻底清除坏死骨组织的同时,尽可能多的保留正常骨组织。根据坏死股骨头囊腔大小取自体骨植入后置入钽棒。结果高速旋切刀进行髓芯减压具有：①彻底清除坏死骨组织,改善关节内环境,从而有效减轻疼痛;②清除骨组织后,可取自体骨植入囊腔,有利于保持股骨头的完整性,可预防股骨头塌陷。结论高速旋切刀具有操作简单、减压彻底,可用清除坏死骨头内死骨,为髓芯减压提供了一种新型方法。     

高速旋切刀在髓芯减压钽棒置人术中的临床应用

目的 探讨高速旋切刀在髓芯减压钽棒术中置入坏死骨组织中的临床应用.方法 应用高速旋切刀在进行髓芯减压,彻底清除坏死骨组织的同时,尽可能多的保留正常骨组织.根据坏死股骨头囊腔大小取自体骨植入后置入钽棒.结果 高速旋切刀进行髓芯减压具有:①彻底清除坏死骨组织,改善关节内环境,从而有效减轻疼痛;（②清除骨组织后,可取自体骨植入囊腔,有利于保持股骨头的完整性,可预防股骨头塌陷.结论 高速旋切刀具有操作简单、减压彻底,可用清除坏死骨头内死骨,为髓芯减压提供了一种新型方法.     

内支撑术治疗成人股骨头坏死的临床观察和有限元分析

目的总结内支撑术治疗成人股骨头坏死的临床效果，并用有限元的方法进行生物力学分析。方法采用微创减压植骨内支撑术治疗早期股骨头坏死共52例67髋，从术前、术后X线片，疼痛和关节活动度三方面对疗效进行评价。建立股骨头坏死三维有限元模型，测定内支架植入前、后股骨头内部和股骨颈的应力。结果经过1年以上的随访，未发生塌陷或塌陷无加重的43髋，占64．296；11髋塌陷加重不超过2mm，占16．496；10髋塌陷加重不超过4mm，占14．996；3髋塌陷加重超过4mm，占4．596。有限元分析证明，内支架植入后股骨头内的应力峰值较内支架植入前减少约30％。结论内支撑术能够减少股骨头的应力负荷，稳定股骨头的内环境，有利于坏死修复，可有效预防股骨头坏死塌陷。     

应用多孔钽重建棒治疗早期股骨头坏死

目的探讨应用多孔钽重建棒治疗早期股骨头坏死的临床效果。方法应用多孔钽重建棒治疗8例早期股骨头坏死的患者。结果 8例术后无内固定松动、断裂等并发症。X线片复查股骨头坏死分期未加重,肢体功能按Harris评分标准,优6例,良2例。结论应用多孔钽重建棒治疗早期股骨头坏死,可延缓股骨头塌陷,推迟了全髋关节置换的时间,为临床提供了一个新选择。     

内支撑术治疗成人股骨头坏死的临床观察和有限元分析

目的总结内支撑术治疗成人股骨头坏死的临床效果,并用有限元的方法进行生物力学分析。方法采用微创减压植骨内支撑术治疗早期股骨头坏死共52例67髋,从术前、术后X线片,疼痛和关节活动度三方面对疗效进行评价。建立股骨头坏死三维有限元模型,测定内支架植入前、后股骨头内部和股骨颈的应力。结果经过1年以上的随访,未发生塌陷或塌陷无加重的43髋,占64·2%;11髋塌陷加重不超过2mm,占16·4%;10髋塌陷加重不超过4mm,占14·9%;3髋塌陷加重超过4mm,占4·5%。有限元分析证明,内支架植入后股骨头内的应力峰值较内支架植入前减少约30%。结论内支撑术能够减少股骨头的应力负荷,稳定股骨头的内环境,有利于坏死修复,可有效预防股骨头坏死塌陷。     

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.     

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.     

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.     

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.