腰椎棘突间内固定器研究进展

腰椎棘突间非融合技术是脊柱外科的新技术,可保留椎间盘和关节突关节的完整性,维持或恢复节段间正常活动,且对邻近节段无明显影响。腰椎棘突间内固定器可用于治疗退变性椎管狭窄、椎间盘源性腰背痛、关节突综合征、椎间盘突出症和腰椎不稳等疾病。该文就腰椎棘突间内固定器设计原理及适应证、生物力学研究和临床应用研究进展作一综述。     

非融合棘突间撑开器治疗腰椎早期退变性腰痛的三维有限元分析

目的建立非融合棘突间撑开器(IPD)及腰椎L4、5节段有限元模型,对撑开器植入前后力学环境进行研究。方法腰椎行CT扫描,根据CT生成实体模型,与撑开器模型一起导入PATRAN生成有限元模型,施加中立位及后伸负荷分析椎间盘受力。结果中立位负荷时IPD受力小;后伸时IPD可分担椎间盘负荷,但L5椎弓根负荷增大。结论基于CT及CAD可建立非融合棘突间撑开器及腰椎的有限元模型,棘突间撑开器可分担后伸时椎间盘的负荷,但可能会增加L5椎弓根崩裂的危险。     

腰椎非融合技术研究进展

腰椎融合术作为脊柱外科治疗腰椎退行性疾病的经典术式,发展至今已有百余年历史。通过坚强的椎弓根钉内固定加上椎间融合技术可以获得很高的责任节段融合率,但其也存在一些问题,最为突出的是相邻节段会分担更多的应力,应力增加会造成退变加速。腰椎非融合技术最大优势在于保留责任节段活动度,从而维持腰椎的生物力学稳定性,减缓邻近节段退变速度。目前临床应用较多的非融合技术有人工髓核及椎间盘置换术、棘突间动态固定系统、经椎弓根动态固定系统等。该文就腰椎非融合技术研究进展进行综述。     

腰椎棘突间撑开器的研究进展

腰椎棘突间撑开器作为动态稳定系统的重要内容,通过在棘突间置入撑开装置,除了对病变节段的后伸活动有一定限制外,基本保留了椎间的生理活动,扩大了椎管以及椎间孔的容积,减轻了椎间盘后部的负荷,且对相邻节段的活动和负荷传递并没有明显的影响。从现有的资料来看,多种棘突间撑开器的生物力学和临床研究结果均令人鼓舞,本文就其应用研究现状进行了综述。     

腰椎棘突间非融合技术的研究进展

目的对腰椎棘突间非融合技术的发展现状、结构特点与临床应用进展进行综述。方法查阅近年相关文献,系统回顾腰椎棘突间非融合技术的发展历程和重要研究成果。结果腰椎棘突间非融合技术是脊柱外科后路非融合植入物的一类,根据设计可分为动态和静态系统两大类,动态系统包括Coflex器械和椎间辅助运动装置,静态系统包括X-STOP器械、ExtenSure器械和Wallis器械。腰椎棘突间非融合技术是脊柱外科的新技术,可以保留椎间盘和关节突关节功能的完整性,维持或恢复节段间正常运动,且对邻近节段无不利影响。腰椎棘突间内固定系统可治疗退行性腰椎管狭窄、椎间盘源性下腰痛、关节突综合征、腰椎间盘突出症和腰椎不稳等疾病。结论随着腰椎棘突间非融合技术日趋成熟和各种类型内固定器械研究的日益增多,腰椎退变性疾病的治疗将进一步发展,但其远期疗效、确切手术适应证等有待深入研究。     

腰椎人工椎间盘置换术的研究进展

正退行性腰椎椎间盘疾病引起的腰痛(椎间盘源性腰痛)主要有非手术治疗或者责任节段椎间融合治疗两种方式[1]。但融合术后的假关节形成、邻近节段退变加剧等问题促使包括腰椎人工椎间盘置换术(TDR)在内的非融合手术技术迅速发展并成为腰椎融合术的备用选择[2、3]。相对椎间融合技术,腰椎人工椎间盘置换术在缓解症状的同时具     

Dynesys动态稳定系统与腰椎退变性疾病

传统的脊柱融合术是治疗腰椎退变性疾病的金标准.越来越多证据表明,融合后腰部活动受限制、脊柱动力学改变和邻近节段加速退变可导致腰椎不稳和椎管狭窄复发.非融合技术也称为动态固定,开始受到关注.非融合固定可通过非融合方法有效改善腰椎节段间的应力传导,缓解疼痛并预防邻近关节退变的发生,其远期效果在于异常活动被控制后,椎间盘在动态固定保护下可自身修复或延缓退变.绝大多数临床结果显示,非融合疗效与传统融合术相当,但创伤较小,不会增加邻近节段继发退变等风险,更符合脊柱生理性稳定.该文主要介绍后路经椎弓根动态稳定系统Dynesys的设计理念、治疗原理、临床应用及治疗效果等.     

腰椎棘突间内固定临床疗效评价的研究进展

腰椎棘突间内固定是当前脊柱外科非融合手术研究领域的热点之一,其特点足保留脊柱节段的运动功能,以避免脊丰丰融合术后节段的应力改变,从而避免邻近节段退变.近年来随着脊柱非融合手术观念的深入,各种腰椎棘突间内固定系统发展迅猛,并在临床治疗中得到了较广泛的应用,其临床疗效评价也成为大家关注的焦点,本文对近年来各腰椎棘突间内固定系统的临床疗效研究做一综述.     

应用两种棘突间撑开系统治疗早期腰椎退变的影像学及疗效比较

[目的]回顾性对照研究Wallis、Coflex两种棘突间撑开装置治疗早期腰椎退变的临床学及影像学结果.[方法]2007年10月～2009年2月,共治疗54例轻度至中度腰椎管狭窄症患者,均为L1、5间隙.其中Coflex组32例,男14例,女18例;平均年龄47岁,Wallis组20例,男8例,女12例;平均年龄49岁.所有病人均行腰椎椎板开窗+髓核摘除减压+棘突间撑开系统植入术,患者术前、术后3个月及末次随访时拍腰椎正侧位及动力位X线片,分别测量椎间盘前、后缘高度,椎间孔高度,手术节段活动范围,同时进行Oswestry功能障碍评分(ODI)及VAS评分.Coflex 组术后平均随访25个月,Wallis组术后平均随访20个月.[结果]两组病人术后ODI及VAS评分均明显下降(P<0.01),两组术后3个月椎间盘后缘高度及椎间孔高度均较术前明显增加(P<0.05),但末次随访时高度有所丢失.椎间盘前缘高度术后各个随访点与术前无统计学差异.手术节段活动度均较术前有所下降(P<0.05),两组之间比较无明显差异(P>0.05).[结论]两种棘突间撑开系统作为一种预防及治疗腰椎早期退变疾病的非融合技术,都能取得良好疗效,不因内置物的不同而影响疗效,都能够较好的维持手术节段的椎间盘及椎间孔高度,最大程度保留手术节段的活动度.     

不同手术方法治疗多节段腰椎间盘退变疾病的中长期疗效评价

目的 探讨不同手术方法治疗多节段腰椎间盘退变疾病的临床效果.方法对自2004年6月～2008年1月收治的302例多节段腰椎间盘退变性疾病,均一期行腰椎后路手术,分别给予单纯开窗髓核摘除、后路椎间融合术(PLIF)、经椎间孔腰椎间融合术(TLIF)、棘突间动态固定系统(Coflex)、腰椎后路动态钉棒固定系统(Semi-...     

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.     

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.