Micro-CT及三维打印机制备仿生化数字化组织工程指骨支架材料的研究

目的 采用Micro-Cr扫描采集人类拇指末节指骨三维微观数据并使用三维立体打印机,建立三维指骨支架材料模型,对仿生化、智能化组织工程支架材料的体外构建进行初步探讨.方法 对成年男性新鲜拇指末节标本进行Micro-CT扫描,所得的原始DICOM数据为基础,通过Mimics软件三维处理得到宏观及微观仿生的三维打印STL文件,并通过三维打印机打印出指骨支架三维模型.结果 采用Micro-CT扫描得到的数据用Mimics三维医学处理软件处理后,可直接用三维立体打印机快速成型构建仿生化、数字化组织工程指骨支架材料.结论 基于Micro- CT及三维打印机的仿生化、智能化组织工程骨建模技术对治疗指骨毁损伤有重要的临床意义,且有良好的应用前景.     

基于Micro-CT的三维打印组织工程骨建模技术

目的建立符合组织工程要求支架材料的空间构型,建立支架材料CAD的微观建模。方法以Micro-CT所得的DICOM文件作为三维建模的输入文件,通过对生物骨骼组织构造研究,对DICOM格式的CT数据按灰度进行筛选,结合大量断面数据得到骨结构轮廓,进行微观仿生骨组织建模,得到骨骼微观结构的STL文件。结果建立基于通过Micro-CT所得的DICOM文件,可建立的骨骼微观结构的STL文件。结论Micro-CT所得仿生三维模型对三维打印组织工程骨建模技术有重要意义。     

三维可视化与三维打印技术在结构性心脏病介入治疗中的应用

三维(3D)可视化是借助计算机软件将二维图像数据转化为三维立体化模型的过程, 3D打印技术是在三维可视化的基础上通过3D打印机构建器官实体模型的过程。随着结构性心脏病介入技术的发展, 三维可视化与3D打印技术在心脏解剖结构的理解和个性化手术方案的制定方面发挥了积极的作用。本文将讨论三维可视化模型的构建, 回顾分析近年来3D打印技术在结构性心脏病介入治疗中应用, 探讨该领域的未来发展, 并简要分析其目前存在的问题。     

3D打印技术辅助复杂主动脉夹层腔内治疗

目的探讨3D打印技术对复杂主动脉夹层(Stanford B型)腔内治疗的术前评估的可行性和有效性。方法获取Stanford B型主动脉夹层CT数据,3D打印主动脉夹层关注部分;3D打印模型术前评估。结果 3D打印模型不仅能够准确辅助选择主动脉支架,而且能够评估支架不同位置导致的主动脉弓形变情况,从而辅助手术方案选择。结论 3D打印技术辅助复杂解剖条件的主动脉夹层腔内治疗方案选择是可行有效的方式。     

计算机辅助设计及电子束熔融快速成型金属3D打印技术制备个性化股骨假体

目的探讨计算机辅助设计技术联合电子束熔融快速成型(electron beammelting rapid prototyping,EBM-RP)金属3D打印技术制备个性化股骨假体的可行性。方法采用64层螺旋CT对1具成年男性左侧股骨标本进行扫描,将获得的断层图像数据导入Mimics15.0软件重建股骨三维模型,再应用UG 8.0软件设计个性化股骨假体三维模型;最后导入EBM-RP金属3D打印机打印个性化袖套。结果根据个体化股骨假体三维模型,采用EBM-RP金属3D打印技术成功制备个性化袖套,与SR股骨柄体组配,制成个性化股骨假体。结论通过薄层CT扫描及计算机辅助设计技术可设计与干骺端良好匹配的个性化股骨假体;采用EBM-RP金属3D打印技术可打印具有复杂三维形态、表面微孔、与干骺端髓腔匹配的钛合金个性化股骨假体,该技术具有简便、快速、准确的优点。     

3D打印技术在辅助主动脉弓部开窗中的应用

目的 探讨3D打印技术辅助主动脉支架体外开窗在复杂主动脉弓部疾病全腔内治疗中的疗效。方法 回顾性分析2020年12月至2023年3月郑州大学第一附属医院利用3D打印主动脉模型指导主动脉弓部体外开窗联合支架植入治疗的25例复杂主动脉弓部病变患者（包括12例胸主动脉夹层和13例胸主动脉瘤）临床资料。术前利用CTA重建数据制备3D打印主动脉模型,确定手术方案后在3D打印模型的辅助下进行主动脉支架体外开窗并结合束径技术完成胸主动脉腔内修复术。结果 患者均成功完成体外开窗胸主动脉支架置入术。围术期及随访期内弓上分支血流通畅,无严重主动脉相关并发症、脑缺血事件及死亡事件发生。结论 对于解剖复杂的主动脉弓部疾病,利用3D打印模型精准指导主动脉支架体外开窗可提高支架开窗孔与弓上分支血管开口对位的准确率,使主动脉弓部疾病的全腔内治疗更安全有效。     

三维耳郭导板的制作及其在耳郭再造术中的应用

目的：参照小耳畸形患者健侧耳郭影像数据,制作三维耳郭导板,并打印为三维实体模型,为患侧耳郭再造提供手术指导。方法应用Mimics软件对患者健侧耳郭CT数据进行分割、镜像、膨胀等处理,获得患侧耳郭和导板的三维虚拟模型,将其导入3D打印机生产三维实体模型,并应用于临床。结果成功制作出个体化仿真度较高的患侧重建耳郭和导板的三维实体模型,并应用于临床耳郭再造术,用以指导术中精细雕刻耳郭软骨支架,并协助患侧再造耳定位。结论基于Mimics软件和3D打印技术制作的耳郭和导板的数字与实体三维模型,有助于指导术中精细雕刻耳郭软骨支架和定位。     

基于3D金属打印技术锁骨近端解剖钢板的数字化研究

目的：探讨3D金属打印技术结合虚拟设计锁骨近端解剖钢板的可行性。方法：回顾性选择1例52岁男性健康志愿者,运用Mimics15.01,NX12.0等软件设计锁骨近端解剖钢板系统,将STL数据输入3D打印机打印1∶1锁骨模型及锁骨近端解剖钢板,并在体外试验钢板的贴合性和影像学评估螺钉位置的准确性,记录模型的打印时间、钉道设计及锁骨近端解剖钢板制作时间。结果：3D金属打印锁骨近端解剖钢板与锁骨模型贴合良好,锁骨近端锁定螺钉的导向准确,X线及CT扫描显示螺钉位置良好。模型打印时间、钉道设计及锁骨近端解剖钢板制作的时间分别为120、15和300 min。结论：基于3D金属打印技术锁骨近端解剖钢板系统可实现锁骨近端骨折钢板的良好贴合和螺钉精确置入,为锁骨近端骨折的治疗方案提供一种新的精确手术方法。     

3D打印技术在肝脏切除术中的应用

目的探讨3D打印技术在肝脏切除术中的临床应用价值。方法我院2015年3~5月期间对6例肝细胞癌、3例肝血管瘤和3例肝内外胆管结石患者术前常规CT检查后行肝脏3D重建,并存为STL文件,按肝脏实际大小50%~70%、采用聚乳酸材料打印出肝脏模型,然后进行后期处理后分析肝脏解剖、手术规划和模拟手术,选择最优手术路径和方案,在3D打印肝脏模型指导下行肝脏切除。结果肝脏切除方式与术前肝脏模型上手术规划一致,术中平均出血量340 m L,无手术并发症。结论 3D打印肝脏切除术使肝脏切除更加精准、安全。     

3D打印技术和数字化模型在全耳郭撕脱伤个性化耳再造术中的应用

目的 利用CT扫描患者头面部及肋软骨的DICOM数据构建3D打印模型,并通过术前的三维数字化模拟制作雕刻肋软骨耳支架,制定个性化自体肋软骨全耳郭再造的术式.方法 回顾自2018年10月至2020年1月,运城市中心医院整形外科收治的8例全耳郭撕脱伤患者的治疗过程.首先行头面部及肋软骨的CT扫描,收集双侧耳的DICOM数据...     

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.     

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.     

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.     

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.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.     

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.