CT-激光快速成形建立胫骨平台骨折模型

目的 探讨CT骨扫描与快速成形机之间的数字化信息转换，应用CT-激光快速成形技术制造胫骨平台骨折纸质模型，供临床研究。方法 用尸体标本和胫骨平台骨折的CT扫描的影像，通过三维重构，转换成STL格式，使快速成形机制造出实物模型。将标本与模型比较、测量，对模型做出客观评价。结果 纸质模型坚固，形态与标本基本一致，矢状径与冠状径的误差在1～1．5mm，胫骨平台骨折模型与术中探查一致。结论 CT-激光快速成形制造的骨折模型能真实反映骨折的现状，利用这项技术不仅可以应用于骨折的临床研究，还可以应用于人工关节置换等领域。     

3D打印技术在复杂胫骨平台骨折治疗中的临床应用

目的探讨3D打印技术在复杂胫骨平台骨折手术治疗中的可行性和临床应用价值。方法对临床上复杂胫骨平台骨折的患者进行螺旋CT扫描,将其DICOM数据输入计算机中,采用Mimics软件数据处理,应用3D打印技术打印骨折三维模型。按胫骨平台三柱分型重新进行分型,在3D打印模型上确定手术入路及手术体位,并进行骨折的准确复位及钢板放置的选择等模拟手术。结果重建的胫骨平台骨折三维模型能准确反映出骨折移位的方向和程度,可准确的进行骨折的三柱分型,可初步实现胫骨平台骨折的术前手术设计。结论 3D打印技术应用于复杂胫骨平台骨折的治疗,临床可行性良好,可作为术前准备的常规项目。     

计算机三维仿真技术与常规手术治疗胫骨平台骨折的疗效对比分析

目的探讨应用计算机三维仿真技术治疗胫骨平台骨折的疗效。方法应用计算机-快速成形技术治疗胫骨平台骨折73例(计算机辅助组),术前采取CT三维重建、计算机模拟、快速成型与个体化标本预手术;采用常规手术方法治疗62例(常规手术组)。两组病例记录手术时间和出血量,术后均采用Merchant评分评定膝关节功能。结果随访6～34个月,平均17个月。计算机辅助组获得随访52例,优31例,良16例,可3例,差2例,优良率90.4%。常规手术组获得随访47例,优20例,良19例,可6例,差3例,优良率83.0%。与常规手术组比较,计算机辅助组术中出血量少,手术时间短,差异有统计学意义(P0.01),术后功能评分优良率高。结论计算机-快速成形技术有助于术前个体化手术方案的设计,并能提高胫骨平台骨折手术效率与精确度。     

胫骨平台隐匿性骨折的CT诊断价值

目的 评价CT检查技术对隐匿性胫骨平台骨折诊断的应用价值. 方法 X线平片诊断可疑或阴性而临床体格检查怀疑胫骨平台骨折的30例患者均行膝关节CT扫描检查.对全部患者的CT表现进行了回顾性分析,并与X线平片相对照. 结果 可疑骨折的30例患者行CT扫描,25例可见不同类型的胫骨平台骨折,对临床体检可疑而X线平片未能确诊骨折患者的检出率为83.3％. 结论 CT检查对隐匿性胫骨平台骨折的诊断具有较高特异性和准确性,当临床怀疑骨折而X线平片无法确诊者应进行CT扫描检查.     

CT扫描对胫骨平台骨折分型及治疗的影响

目的 探讨CT扫描对胫骨平台骨折分型及治疗方法选择的影响。方法 2003年2月～2004年5月对83例86侧胫骨平台骨折患者的临床资料进行分析。其中男53例，女30例；平均年龄43岁（17～63岁）。左55侧，右3l侧，3例为双侧胫骨平台骨折。术前均摄正、侧位X线片及CT扫描。按照胫骨平台骨折Schatzker分型方法，对常规普通X线片与结合CT扫描的分型结果进行比较。同时发现并比较隐匿合并的胫骨髁间棘骨折及腓骨近端骨折。结果 86侧中19侧（22．1％）参考CT扫描结果后更改分型，其中7侧（36．8％）更改内固定手术方法，占全部86侧骨折的8．1％，30侧胫骨髁间棘骨折及13侧腓骨近端骨折在常规X线片检查中未发现，后经CT扫描证实。各分型间合并胫骨髁间棘骨折及腓骨近端骨折的发生率差异无显著性意义（P〉0．05）．结论 CT扫描对胫骨平台骨折分型及治疗方法的选择具有重要影响。虽然会增加患者的治疗费用，但应作为术前常规检查加以应用。     

QCT辅助评价胫骨平台骨折形态的临床分析与应用研究

目的 通过地图投影技术及定量CT(Quantitative computed tomography,QCT)影像技术评估胫骨平台五柱分型下骨折形态、骨密度在临床诊疗上的价值。方法 收集自2018-08—2022-07诊治的68例胫骨平台骨折的三维CT影像数据,应用Mimics 20.0软件重建健侧胫骨平台标准3D模型,对患侧骨折区域进行三维重建、复位,将复位的三维骨折模型导入3-matic软件中,在标准模型上识别骨折区域并叠加,应用MATLAB软件进行三维热图可视化处理。按照胫骨平台五柱分型,观察胫骨平台骨折区域三维图形在二维平面下各柱形态变化及骨折发生率,同时在健侧胫骨平台内外侧标记感兴趣区域,应用QCT准确获取骨密度值,对比内外侧柱骨密度值与骨折形态的相关影响。结果 胫骨平台骨折三维重建结果显示胫骨平台前内侧柱骨折19例,占比27.94%;胫骨平台前侧柱（结节区域）骨折30例,占比44.11%;胫骨平台前外侧柱骨折53例,占比77.94%;胫骨平台后外侧柱骨折42例,占比61.76%;胫骨平台后内侧柱骨折24例,占比35.29%。骨折热图结果及分布比例显示前外侧柱及后外侧柱骨折分布...     

3D打印技术在复杂胫骨平台骨折治疗中的应用

目的探讨3D打印技术在胫骨平台复杂性骨折临床应用的意义。方法笔者自2014-07—2014-11应用3D打印技术诊治6例复杂性胫骨平台骨折,经术前64排双源CT数字成像、Mimics软件处理后、3D打印机打印1∶1骨折模型、进行术前复位固定预演,手术按照术前预演目标进行手术,术后用Rasmussen胫骨平台标准评分。结果本组术后全部骨折解剖复位,三维CT复查与术前手术预演时固定物吻合率100%,所有患者切口均一期愈合,无感染,血管和神经损伤等并发症发生。所有患者获得平均3(1~6)个月随访,采用Rasmussen胫骨平台骨折解剖学评分评定,优5例,良1例。结论 3D打印技术在复杂性胫骨平台骨折手术治疗中可延展术前设计、精准手术过程、缩短手术时间、直观与患者交流程度、并减少并发症发生均有较实际临床意义。     

胫骨平台骨折的治疗新进展

胫骨平台骨折在临床中是常见的关节内骨折,随着现代骨科的发展以及研究的不断深入,治疗方法在逐步改进和完善,治疗概念也不断更新,本文就近年来胫骨平台骨折治疗的新进展作如下综述. 1胫骨平台骨折的影像学诊断及骨折分型 X线片仍然是常规检查方法,CT三维图像重建成像能立体显示骨折位置和范围,MRI检查对诊断侧副韧带、前后交叉韧带的撕裂及半月板损伤有较高诊断价值.近年来,三维重建胫骨平台骨折可视模型,可在计算机上实现快速成型1∶1重建等大骨折模型,明确骨折类型,模拟手术,制定手术方案,但昂贵的设备及技术的复杂使该技术广泛应用还有待时日[1].     

快速成型模型在制定胫骨平台复杂骨折手术方案中的指导作用

目的 探讨快速成型技术制备的模型在胫骨平台复杂骨折手术方案制定中的指导作用. 方法 2006年11月至2010年11月收治16例胫骨平台复杂患者,男10例,女6例;年龄27～68岁,平均39岁.术前根据X线片和CT进行AO分型;41B2.2型4例,41B3.2型3例,41B3.3 型2例,41C2.1型1例,41C3.1型2例,41C3.2型2例,41C3.3型2例.术前均进行三维螺旋CT扫描,所得数据经转化输入决速成型机,制备出了1:1等大的快速成型胫骨平台骨折模型,明确骨折类型并指导制定手术方案,术后随访了解骨折愈合与患膝功能情况. 结果 2例患者骨折分型由AO41B2.2型修正为41B3.1型,1例患者骨折分型由41C2.1型修正为41C3.1型.模型上进行了损伤机制的分析和手术方案的制定.所有患者术后获9～22个月(平均14个月)随访,骨折均获骨性愈合,愈合时间4～6个月(平均4.7个月),术后膝关节功能参照改良HSS膝关节评分系统评定:优11例,良3例,可2例,优良率为87.5％.结论 采用快速成型技术制备的1:1等大胫骨平台骨折模型使骨折伤情更直观,骨折分型更加准确;可根据骨折模型制定手术方案,并可对内固定钢板进行预先塑形,对复杂类型的骨科手术方案的制定有较强的指导作用.     

数字化快速成形技术在骨折畸形愈合个体化治疗的应用研究

目的通过数字骨科技术,利用计算机辅助设计软件及快速成形技术,初步探究数字骨科、快速成形技术在矫形外科手术中的应用意义。为骨折畸形愈合个体化手术方案的制定和实施提供一种参考方向。方法选择1例胫骨骨折术后畸形愈合的患者,进行双下肢DR摄影、连续螺旋CT扫描,利用数字骨科软件计算机分析、计算与数字化快速成形技术重建患者畸形骨骼模型,根据患肢在三维空间内的畸形情况,并通过计算机分析、计算截骨角度及截骨方向,并设计截骨导航模板,制定手术方案及术前模拟手术操作。术中将快速成形技术制作的截骨导航模板置于胫骨畸形愈合处,按照预先通过数字骨科技术设计的截骨角度进行截骨,后用骨延长支架进行固定。结果手术过程与术前模拟手术操作完全一致,通过数字骨科技术设计的截骨导航模板与患者胫骨畸形愈合处精确匹配,缩短了手术时间,减少了周围软组织损伤,手术顺利,无并发症,患者术后恢复好。结论数字化快速成形技术能够使骨科医生在术前精确、直观地了解四肢骨折畸形愈合的情况,提高诊断率,精确指导制定手术方案,模拟手术操作,提高了手术的精确性、安全性,缩短了手术时间。     

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.     

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.