近排腕骨切除术后对腕关节生物力学影响的实验研究

目的测定正常腕关节和近排腕骨切除术后腕关节的活动范围和生物力学变化,探讨近排腕骨切除术后腕关节功能丧失和并发症出现的机制。方法选用16例新鲜腕关节标本,通过CSS-44020系列生物力学试验机(中国长春试验机研究所制造),牵引腕关节于被动掌屈、背伸、尺偏和桡偏位,测量正常腕关节和近排腕骨切除术后腕关节的活动范围。然后在腕关节内放置压敏片,于中立位对腕关节施压,分析压敏片上相关信息。结果正常腕关节标本掌屈(74.2°±4.9°,-x±s,下同)、背伸63.3°±3.6°、尺偏36.8°±2.6°、桡偏20.2°±3.4°。近排腕骨切除后掌屈48.1°±5.6°、背伸43.6°±4.6°、尺偏21.0°±4.3°、桡偏10.3°±4.1°。正常腕关节的受力面积平均为(640.57±23.15)mm2,近排腕骨摘除组为(81.26±2.38)mm2。正常腕关节负荷压力为(27.68±0.73)N/cm2,近排腕骨切除组为(169.81±2.27)N/cm2。结论近排腕骨切除术后腕关节活动范围丧失较大,其应力负荷的增加明显超出了正常腕关节所承受的压力负荷,使腕关节功能丧失较多并容易在术后产生腕关节退行性关节炎等并发症。     

部分腕骨融合术对腕关节生物力学影响的实验研究

目的探讨部分腕骨融合术后腕关节的活动范围、压力负荷及对腕关节生理状态的影响。方法选用12例新鲜腕关节标本随机分为3组,A组舟大小融合术;B组舟骨三角骨切除+头月融合术;C组四角融合+舟骨切除术。通过CSS-44020系列生物力学试验机,用100N力,以5mm/s的速度分别牵引腕关节被动掌屈、背伸、尺偏和桡偏,并测量A、B、C3组标本的活动角度。然后,于腕关节内放置压敏片,用自制的实验架将腕关节固定于中立位,以5N/s的压速对腕关节施压至200N,维持60s后测量压敏片上各组标本的受力面积和压力负荷。结果(1)活动范围A组掌屈(68.4±5.2)°(x-±s,下同)、背伸(51.5±4.6)°、尺偏(24.5±2.3)°、桡偏(15.7±3.4)°。B组掌屈(64.5±7.1)°、背伸(60.0±5.2)°、尺偏(42.4±3.2)°、桡偏(26.9±5.2)°。C组掌屈(61.9±6.6)°、背伸(54.9±5.3)°、尺偏(27.1±3.9)°、桡偏(17.0±4.9)°。(2)腕关节的受力面积A组为(265.00±8.97)mm2。B组为(125.81±5.97)mm2。C组为(164.00±8.43)mm2。(3)负荷压力A组为(53.87±3.07)N/cm2。B组为(112.86±0.74)N/cm2。C组为(55.28±5.11)N/cm2。结论舟大小融合术、舟骨切除+四角融合术对腕关节应力负荷的影响与正常腕关节相比变化不大,而舟三角骨切除+头月融合术对腕关节的影响较大,其应力负荷的增加明显超出了正常腕关节所承受的压力负荷。     

近排腕骨切除术后桡腕关节的解剖学及生物力学变化

目的研究近排腕骨切除术后新的桡腕-桡头关节的解剖学特点及生物力学变化，增强临床对这一术式的理解。方法6只福尔马林固定的尸体腕标本，模拟近排腕骨切除术后观测头状骨近端关节面；纵性剖开头状骨及月骨，描拓桡月关节和桡头关节的匹配曲线；选用6只新鲜标本牙托粉包埋后，用压敏片在双轴液压材料测试系统上测试正常和术后桡腕关节的接触面积和压力变化。数据进行统计学处理。结果正常桡月关节匹配曲线良好，腕骨切除术后头状骨近端关节面有4个子关节面，和桡骨远端的桡月窝匹配性差。腕中立位下，正常的平均腕单位面积负荷为（22．9±4．3）N／cm^2。近排腕骨切除术后为（136．4±30．7）N／cm。（P〈0．05）。结论近排腕骨切除术后形成的新桡腕关节-桡头关节其解剖学和生物力学都明显异常。     

部分腕骨融合术或切除术对腕关节运动影响的实验研究

目的 研究临床常用的部分腕骨融合术或切除术对腕关节运动的影响程度。方法 将１２侧新鲜上肢处理后,固定于特制的测试架上,在腕背部打入２根或多根克氏针,作舟头骨、舟大小多角骨、舟月骨、月三解骨、桡月骨、ｆｏｕｒ ｃｏｒｎｅｒ、头月骨融合术、舟骨切除＋ｆｏｕｒ ｃｏｒｎｅｒ、舟骨切除＋头月融合术。观测腕关节正常运动活动范围,及作上述不同部分腕骨融合术后腕关节屈曲、伸腕、尺偏、桡偏度数。结果 桡舟月骨融合     

局限性融合腕舟骨、大、小多角骨的稳定性研究

目的探讨局限性融合腕舟骨、大、小多角骨(scaphoid-trapezium-trapezoid,STT)的稳定性。方法取6具新鲜成人尸体(男4具,女2具)前臂以远标本,依次切断腕关节的桡月韧带、舟月骨间韧带、桡月头韧带、舟大多角韧带、舟头韧带,建立静态舟月分离的腕关节模型。用自行研发的新型STT融合器在标本上模拟STT融合术,并将其固定于腕关节动力学参数仪,分别模拟腕关节背伸35°-掌屈50°、桡偏10°-尺偏30°各5万次极限运动。运动前后摄腕关节正侧位X线片,测量舟骨长度、桡舟间距及桡舟角变化,观察融合器各部分有无松动、变形或断裂,并对数据行统计学处理。结果腕关节各方向极限运动前后,作为局限性融合体稳定性指标的舟骨长度、桡舟间距及桡舟角的差异无统计学意义(P>0.05),极限运动后STT融合器无松动、变形或断裂。结论应用新型STT融合器模拟STT局限性融合术后,在腕关节背伸35°-掌屈50°、桡偏10°-尺偏30°范围内进行各方向极限运动,局限性腕骨融合体不发生位移。应用新型STT融合器行局限性腕骨融合稳定性好。     

正常腕关节桡腕关节面应力分布的实验研究

目的　明确正常腕关节桡腕关节面的应力分布特点及其与腕关节位置的关系。方法　 5侧标本通过克氏针固定前臂于中立位 ,调整加载支架 ,使腕关节分别处于中立、掌屈 30°、背伸 30°、尺偏 30°及桡偏 1 0°,通过桡侧、尺侧屈腕肌腱、桡侧、尺侧伸腕肌腱 ,垂直加载 1 2kg固定负荷 ,富士压敏薄膜通过腕关节背侧切口置入 ,应用颜色密度测量仪FPD— 30 5E及密度压力转换器FPD— 30 6E分别测量舟骨窝、月骨窝的应力。结果　舟骨窝及月骨窝内应力分布不同 ,且随腕关节位置的改变而变化。结论　正常腕关节桡腕关节面存在两个相对独立的应力分布区 ;桡舟关节并非紧密嵌合 ,舟骨窝内应力分布不均匀 ;桡月关节在腕关节中立、掌屈、尺偏位时嵌合不紧密 ,月骨窝内应力分布不均 ;而在腕关节背伸、桡偏时嵌合紧密 ,应力均匀分布 ;腕关节背伸位时 ,舟骨窝及月骨窝的应力最大     

腕塌陷的诊断和治疗进展

最近20年对腕塌陷有系统研究，X线片诊断标准的提出和修正进一步明确了腕塌陷的概念，舟月进行性腕塌陷分期法帮助临床医生更客观地追踪该病的发展和愈后。相关生物力学的研究使对此症病理机制的认识大为加深，并且成为手术方法选择的重要参考依据。以四角融合术为代表的各种部分腕骨合术和近排腕骨切除术右以有效缓解症状，阴止腕塌陷的继续，成为该病的主要治疗手段，但必须要根据桡腕关节和腕中关节的具体情况灵活使用。硅胶假体置换术由于其明显的并发症基本被淘汰。     

近排腕骨切除术治疗创伤性腕关节炎10例临床观察

[目的]评价近排腕骨切除术治疗创伤性腕关节炎的疗效。[方法]2009年3月~2014年12月,对10例创伤性腕关节炎行近排腕骨切除术。术后测量腕关节的活动度、握力和疼痛程度,腕关节功能评定采用Krimmer评分法。术后拍摄腕关节正侧位X线片,了解腕关节骨性改变情况。[结果]术后随访8~66个月。腕关节屈伸活动度(腕关节掌屈、背伸角度之和)平均为73°(健侧为127°),尺桡偏平均为37°(健侧为67°);握力为24 kg(健侧为48 kg);疼痛值为30(术前为75);腕关节功能评分为82分(术前为56分)。腕关节X线片示:术后1例桡头关节形成关节炎。[结论]近排腕骨切除可保留腕关节部分功能,减轻腕关节疼痛,是治疗创伤性腕关节炎的有效手段。     

腕舟骨、大、小多角骨三关节应用解剖学研究

目的为探讨局限性腕骨融合术新型内固定方式提供腕舟骨、大、小多角骨(scaphoid trapez-iumtrapezoid,STT)三关节的应用解剖学数据。方法取30具尸体腕关节标本,测量STT关节中心至舟骨桡腕背侧韧带附着处的最短距离及STT关节深度。结果STT关节中心至舟骨桡腕背侧韧带附着处的最短距离为[(6.03±0.14)mm,x-±s,下同],95%的可信区间为5.74~6.32mm。STT关节深度为(13.83±0.30)mm,95%的可信区间为13.22~14.45mm。结论本研究为探讨局限性腕骨融合术新型内固定方式提供了重要的解剖学数据。     

四角融合术后腕关节稳定性的衡量指标

目的提出衡量腕关节四角融合术后融合体稳定性的指标,探讨术后如何改善腕功能。方法12具新鲜尸体前臂标本,男8具,女4具,左右各6肢,模拟行四角融合术后,固定于腕关节动力学测试仪上,模拟腕关节的掌屈、背伸、尺倾、桡倾等运动,运动前后摄腕关节正、侧位X线片,测量并观察头月角(α)、桡月角(β)、头月正位角(θ)、融合体高度(H)和融合体宽度(W)的变化,并行统计学分析。结果腕关节由运动前中立位至掌屈50°时,α、β、H值与运动前相比,差异均有统计学意义(P<0.01);背伸至40°时,α、β、H值与运动前相比,差异有统计学意义(P<0.01)。腕关节由中立位至桡倾15°时,θ与W与运动前比较,差异有统计学意义(P<0.05);至尺倾25°时,θ与W的运动前比较,差异有统计学意义(P<0.05)。结论头月角、桡月角、头月正位角、融合体高度和融合体宽度等指标可用于衡量四角融合术后融合体的稳定性。     

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.     

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.     

Immunomodulation in Transplantation with Photopheresis

Abstract: Photopheresis is a technique in which peripheral blood mononuclear cells, in the presence of a photoacti-vatable compound, are exposed extracorporeally to ultraviolet A light and reinfused, inducing a host autoregula-tory immune response. Experimental work and ongoing clinical studies are helping to define the role of this novel, safe, and non-toxic immunomodulating technology in the field of transplantation.