骨科——脊柱

经口咽前路寰枢椎复位钢板内固定的外科解剖学研究；用Gallie术式治疗寰枢关节不稳定的临床问题研究；枢椎椎体骨折;颈椎前路手术并发食道瘘的诊断与治疗；颈部旋转与侧屈活动对椎动脉血供的影响；颈脊柱姿势及预负荷史对压缩强度影响的生物力学研究；颈椎前路带锁钢板内固定治疗颈椎骨折并四肢瘫痪；前路螺钉固定治疗齿状突骨折脱位合并颈髓不全损伤27例；经寰椎后弓侧块螺钉固定治疗上颈椎损伤；短节段内固定、ACPC椎体成形治疗胸腰椎骨折的围手术期观察；颈椎疾病前后路手术的选择与并发症的防治(附512例报告)；     

前路椎体撑开后颈椎三维活动度测量

目的：旨在研究颈椎前路椎体撑开椎管扩大后对颈椎运动稳定性的影响，以求为新的术式设计提供实验参数。方法：采用新鲜尸体标本8具，于C5椎体正中部分切除开骨槽10mm，撑开骨槽达15mm后植入楔形骨块维持，AO前路带锁钢板固定C4一C6节段，分别对正常、撑开植骨及AO前路带锁钢板固定3种状态进行脊往三维运动测量与稳定性分析。结果：颈椎椎体撑开后，与正常组相比，除后伸运动范围稍增大外，其余运动范围均减小；前路钢板固定后三维运动范围均显著减小。结论：颈椎前路椎体撑开椎管扩大后，相应椎节活动废减小，稳定性增加，即刻恢复稳定应行前路内固定。     

颈前路钛制网状接骨板固定系统的生物力学研究

目的:对自行研制的颈前路钛制网状接骨板固定系统(ACSRP)进行生物力学评价.方法:(1)稳定测试 14例新鲜颈椎标本,随机分为A、B两组,模拟颈椎前路手术制作颈椎双间隙并部分椎体摘除的模型.分别以网状接骨板(ACSRP)和进口Caspar钢板固定,依次测量两类颈椎模型的三维运动数据;(2)植骨块的应力测试选择压力敏感胶片,分别置于A、B两组C4～C6与植入髂骨块之间,计算出其所受应力大小.结果:(1)损伤颈椎在两种钢板固定后的ROM均明显减少,稳定程度增加,但提高颈椎的稳定程度不同;(2)压敏片测量ACSRP固定后的植骨块与Caspar组间应力分布有差异.结论:ACSRP有较好的生物力学稳定作用,ACSRP固定的植骨块较Caspar组固定的植骨块有较好的应力分布.     

Caspar型颈椎撑开器在颈椎间减压手术中的应用研究

目的:探讨使用Caspar型颈椎撑开器在颈前路椎间减压手术中对颈椎椎间角度、椎间孔大小的影响。方法:取10具C2~C7成人颈椎标本,将Caspar型颈椎撑开器的2枚固定螺钉分别在C4、C5椎体正中相互平行置入,按照Smith-Robinson手术方法进行C4/5间隙减压,用颈椎撑开器加压2mm和撑开2mm、4mm,分别在CR机上摄颈椎侧、斜位片,Pacsout程序软件测量C4/5椎间孔面积和椎间角度,SAS6.12软件包进行统计分析。结果:颈椎撑开器压缩2mm,椎间孔面积无明显改变,椎间角度减小39.7%;撑开2mm时,椎间孔面积增加28.3%,椎间角度增加67.6%;撑开4mm时,椎间孔面积增加33.3%,椎间角度增加136.8%。结论:颈椎撑开器撑开椎间隙时扩大了椎间孔面积,同时也增加了椎间角度;提示不应强求使用颈椎撑开器过度撑开椎间隙的方法来增加椎间孔面积。     

椎弓根钉棒系统治疗颈椎不稳定骨折的生物力学研究

目的 研究椎弓根钉棒系统治疗颈椎不稳定骨折的生物力学作用.方法 采用新鲜C3～7段小牛颈椎,制备成椎体屈曲压缩性骨折模型5具(椎管内均有骨块占位),记录椎弓根钉棒系统固定后纵向恒速拉伸过程中各种运动状态下椎管内骨块复位位移变化,描记出纵向拉伸载荷与椎管内骨块复位位移之间的关系曲线.结果 椎管内骨块位移-复位力在起始呈线性变化,但随着位移的增大呈非线性走势;颈椎轴向撑开力为50 N、相同骨块位移值时,前屈状态的骨块回复力比后伸状态大23%(P＜0.05),轴向撑开力为150 N、前屈状态的骨块回复力反而比后伸状态小11 %(P＜0.05);随着轴向撑开力的增大,椎管内骨块回复力增大,即随着载荷的减少,骨块回复的阻力越大.结论 轴向撑开力对椎管内骨折块的复位有重要影响,后纵韧带在骨折块复位过程中起决定性作用.     

颈前路自锁钛板系统的研制和生物力学研究

目的对自行研制的颈前路自锁钛板系统(ACSPS)进行生物力学研究。方法采用18具男性尸体的新鲜颈椎标本,随机分为A、B两组(A组用ACSPS,B组用Caspar),进行载荷-位移及应变测定,并对ACSPS行拔出实验。结果ACSPS和Caspar内固定后颈椎位移的降低幅度,最大拔出力、相对位移、能量吸收值比较差异均无显著性(P>0.05)。结论ACSPS有较高的强度和紧固能力,能提供较好的生物力学稳定作用。     

前路减压不同撑开高度影响颈椎稳定性的生物力学评价

目的:评价颈椎单椎体次全切除减压后不同撑开高度对颈椎生物力学稳定性的影响.方法:48具小牛颈椎标本随机平均分为6组,其中1组作为对照组,5组作为实验组.实验组均行颈椎体次全切除后用自行研制的颈前路可调式融合固定器分别撑开0、2、4、6、8mm,测量各组标本在受到轴向压缩、前屈、后伸、侧屈的不同载荷作用下的总体位移和应变变化.结果:撑开高度为4、6mm时颈椎的总体位移和应变明显下降,如果继续增加撑开高度,颈椎稳定性并不随之增加.结论:单椎体次全切除后撑开高度为4～6mm可获得较好的力学稳定性.     

前路带锁钢板在治疗多节段颈椎骨折中的应用

目的研究并评价前路带锁钢板治疗多节段颈椎骨折的方法。方法20例颈椎多节段骨折患者采用前路减压、取髂骨植骨、前路带锁钢板作内固定治疗。结果19例患者在超过6个月的随访中全部取得了骨性融合,融合率95%。结论颈椎前路带锁钢板能为固定节段椎体提供可靠的稳定性,是一种治疗多节段颈椎骨折的可靠方法。     

颈椎前路钛网钢板内固定及自体髂骨植骨在不同颈椎节段中的生物力学研究

目的 采用颈椎前路钛网钢板及自体髂骨植骨对不同颈椎节段进行内固定，分析其生物力学改变。方法 取自愿捐赠的6具新鲜尸体C3～7标本，C5、C5.6及C4～6椎体次全切除后，分别行髂骨植骨和钛网前路钢板内固定术，测量各节段的前屈、后伸、左、右侧弯及左、右旋转运动变化，以完整标本作为对照组。结果 自体髂骨的植入使失稳颈椎的稳定性提高，其侧弯、屈伸运动度减少，与对照组比较，差异有统计学意义（P〈0．05），但抗旋转运动减少不明显（P〉0．05）。不同颈椎节段开槽减压椎间撑开钛网前路钢板内固定状态下，手术节段的即刻稳定性比对照组及撑开植骨状态增加（P〈0．05）。结论 颈椎前路椎体次全切除之后，植骨仅能部分改善其稳定性，但应用颈椎前路钛网钢板内固定可明显增强颈椎的稳定性，也较完整颈椎运动功能单位稳定。     

下颈椎骨折脱位的治疗术式选择

目的:探讨下颈椎骨折脱位的手术方式选择及其疗效.方法:我院2007年1月至2012年10月收治下颈椎骨折脱位患者32例,男23例,女9例;年龄28～78岁,平均56.4岁.术前伴脊髓损伤22例,Frankel分级A级5例,B级9例,C级6例,D级2例.根据患者骨折类型、椎间盘突出及压迫脊髓程度、小关节交锁情况、颈椎损伤程度等因素选择手术方案,其中21例椎体骨折但不伴有椎间小关节绞锁的病例采用单纯前路于术治疗(单间隙或椎体次全切除减压、椎间植骨钢板内固定);4例颈椎脱位伴有小关节绞锁但不伴有明显的椎体骨折、MRI示脊髓前方无明显受压,或屈曲牵张型双侧关节突骨折/绞锁者行后路减压、复位、内固定;7例有椎体骨折和椎间盘损伤,并存在椎体脱位、椎间小关节绞锁,或椎板骨折、骨块脱入椎管者采用前后联合入路手术.随访患者神经功能改善情况,影像学评价骨折愈合、植骨融合及颈椎稳定性情况:结果:32例均顺利完成手术,术中无神经、气管和食管损伤等并发症.4例术中发现硬脊髓破损,术后发生脑脊液漏,经对症处理后愈合.术后佩戴颈托3个月.均获随访,随访时间6～24个月,平均18.5个月,术后6个月22例有脊髓神经功能损伤患者除1例B级无恢复外,其余患者Frankel分级提高1～2级.术后复查X线片示颈椎序列恢复良好,骨折愈合,植骨均在6个月内获骨性融合(平均4.5个月),无假关节、骨不连发生,椎体间高度、生理曲度及颈椎稳定性维持良好,随访期间无钢板螺钉脱出、断裂.结论:术前对下颈椎骨折脱位患者的损伤类型、损伤节段、颈椎间盘突出压迫脊髓位置及受伤程度等因素进行综合分析,采取合理的手术方式,能够使损伤节段获得早期稳定,有利于提高患者神经功能的恢复.     

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.     

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.     

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.