中后路椎间盘镜治疗腰椎间盘突出症

目的：介绍MED,METRX中后路椎间盘镜治疗腰椎间盘突出症的手术技巧和有关并发症防治。方法：采用MED治疗腰椎间盘突出症62例,METRX治疗101例。结果：随访6－14个月,按Nakal分级,优良率达94％。163例中硬脊膜囊破裂4例,间盘残留复发6例。全部病例无神经损伤和椎间隙感染等严重并发症发生。结论：MED,METRX用于椎间盘突出症的治疗具有安全,损伤小,恢复快等优点,除能摘除突出椎间盘,切除增厚的黄韧带外,还可修整增生的关节突以扩展侧隐窝解除神经根压迫,是治疗腰椎间盘突出症较好的方法之一。     

显微内镜下腰椎间盘切除术围手术期的并发症与处理

目的探讨显微内镜椎间盘切除术(microendoscopic discectomy,MED)围手术期的并发症处理对策。方法回顾性分析我院1999年10月~2006年10月1852例MED治疗腰椎间盘突出症中出现的140例(7.6%)手术并发症的临床资料。结果椎管内静脉丛出血48例:42例通过镜下止血后完成MED,6例改为开放椎间盘摘除术;定位错误47例,术中发现后调整腔镜位置完成手术;硬脊膜破裂21例,2例改为开放手术;髓核遗漏13例,二期再次行MED髓核摘除;神经根损伤6例,经1个月后完全恢复;术后椎间盘炎5例,1例保守治愈,其余4例行椎间病灶清除术后痊愈。结论采用适当的处理措施可有效的防止或减小MED并发症或失误后给患者造成的损害。     

后路显微内镜椎间盘切除术24例短中期随访报告

目的 探讨后路显微内镜椎间盘切除术（microendoscopic discectomy,MED）治疗腰椎间盘突出症或合并侧隐窝狭窄症的疗效。方法 椎间盘镜后路手术,椎板表面剥离软组织,扩大骨窗;剥离子分离椎板下黄韧带,切开黄韧带并咬除,显露硬脊膜及神经根;有隐窝狭窄者,薄椎板咬骨钳沿神经根,潜行咬除侧方黄韧带及增生骨质,必要时用自制小骨刀小心行神经根减压,牵开神经根切开纤维环,取出髓核组织。结果 术中出血量250～700 ml,平均410 ml;手术时间25～300min,平均70 min。硬脊膜破裂1例。24例术后随访12～36个月,按Macnab标准,优18例,良4例,可2例。结论 MED治疗腰椎间盘突出症疗效满意。     

显微内窥镜下椎间盘切除术的适应证选择与疗效

目的：探讨显微内窥镜下椎间盘切除术（MED）治疗腰椎间盘突出症的手术适应证及其临床效果。方法：对357例具有手术指征的腰椎间盘突出症患者，选择其临床表现为单侧腰腿痛、单一神经根受累且腿痛症状大于腰痛、影像学显示单间隙后侧方突出或脱出且无脊椎滑脱和腰椎失稳表现、临床表现与影像学检查结果一致等条件作为开展MED的适应证．共开展MED 166例，占同期腰椎间盘突出症手术的46．5％。结果：平均随访22．6个月，无一例出现硬脊膜及神经根损伤、椎间隙感染等严重并发症．按照Nakai评价标准，优良率为98．7％。结论：MED作为治疗腰椎间盘突出症的一种手段，尚不能完全取代常规开放手术，在掌握开放手术技术的前提下，严格选择手术适应证、灵活运用手术技巧等可提高手术疗效并降低并发症。     

经显微内窥镜治疗腰椎间盘突出症——附42例报告

报道 4 2例 5 0间隙腰椎间盘突出症应用显微内窥镜椎间盘切除系统 (MED)的治疗效果。经 (2～ 8)个月 ,平均 4 .3个月的随访。术后功能评定按照Macnab分级 :优 37例 ,良 4例 ,可 1例 ,并发椎间隙感染 1例。早期的手术出现 2例硬脊膜破裂 ,无神经根损伤或马尾神经损伤等并发症。MED系统在髓核摘除基础上又保证神经根充分减压 ,并具有手术切口小 ,创伤小 ,恢复快特点 ,近期效果满意。     

显微内窥镜手术治疗腰椎间盘突出症

目的 探讨显微内窥镜椎间盘切除系统(MED)治疗腰椎间盘突出症的特点及应用中出现的情况和并发症，以提高手术疗效。方法 通道管经棘突旁小切口进入，在电视监视下显露椎板间隙，咬除少量椎板下缘及黄韧带，扩大椎间隙，显露硬脊膜、神经根以及突出椎间盘的髓核组织并予以摘除；根据神经根是否松弛，作侧隐窝、神经根管扩大。结果 本组87例，术后随访20-31个月，平均26．4个月。手术时间40～160min，平均67min。术中出血30～500ml，平均95．2ml。术后平均2-3d下床，16d恢复日常生活，29d恢复工作。按Nakai标准评定，优良率93．1％：术中可能出现(1)定位错误；(2)进入椎管困难；(3)止血困难；(4)硬脊膜损伤；(5)髓核残留。结论 MED具有创伤小、出血少、恢复快，能直接摘除突出的髓核组织、扩大狭窄的侧隐窝及神经根管对神经根的压迫，最大限度的保持了脊柱后路的稳定性，本术式适用于大多数腰椎间盘突出症或合并侧隐窝狭窄和／或神经根管狭窄症的患者。     

METRX手术系统治疗腰椎间盘突出症早期疗效观察

报道应用METRX椎间盘镜手术系统治疗腰椎间盘突出症64例，行髓核除和神经根管扩大术。随访3月～19月，平均11个月。按Nakai分级：优56例，良6例，可2例。并发症5例，其中硬脊膜损伤3例，神经根牵拉伤1例，髓核残留1例。     

MED治疗腰椎间盘突出症时对神经根变异的探查

目的：观察显微内窥镜下椎间盘切除术（microendoscopic discectomy，MED）治疗腰椎间盘突出症时神经根变异情况，防止出现术中神经根损伤。方法：回顾分析自1999年10月至2003年12月应用MED治疗的腰椎间盘突出症患者724例，其中男452例，女272例。对术中发现存在腰骶神经根变异患者的临床特点及术中所见进行统计分析。结果：724例腰椎间盘突出症患者有37例神经根变异，发生率为5.1％。与术前的临床表现吻合，全部神经根变异患者均在MED下完成手术，无一例出现神经根损伤。结论：仔细探查及分离突出髓核周围神经根发出情况．确定有无神经根变异是防止MED治疗腰椎间盘突出症时发生神经根损伤的重要环节之一。     

显微椎间盘镜手术系统治疗腰椎间盘突出并侧隐窝狭窄症

目的：介绍显微椎间盘镜手术系统(MED)治疗腰椎间盘突出并侧隐窝狭窄症。方法：自2000年10月～2002年12月用MED治疗腰椎间盘突出症108例，其中46例合并有侧隐窝狭窄。结果：随访6～24个月，按Na—Kai疗效评定，34例，良8例，可3例，差1例。优良率为91．3％。结论：应用MED治疗腰椎间盘突出并侧隐窝狭窄症，只要遵循神经根彻底减压的原则，就可取得好的疗效。     

后路脊柱全内镜结合类固醇激素鞘内注射手术治疗腰椎间盘突出症

目的探讨腰椎间盘内镜技术(microendoscopic disectomy,MED)结合类固醇激素神经根鞘内注射治疗腰椎间盘突出症的效果。方法 2010-02—2012-12收治的60例腰椎椎间盘突出患者随机分为MED组30例,行MED手术,MED神经根鞘内注射组治疗30例,行MED手术并在神经根鞘杰注入5 mg地塞米松。记录两组手术前后疼痛视觉模拟量表(visualanalogue scale,VAS)评分、直腿抬高角度及术后恢复正常工作的时间,术中、术后并发症发生情况。结果与治疗前比较,两组患者治疗后VAS评分明显减低,直腿抬高角度明显升高,差异有统计学意义(P0.05);与MED组比较,MED神经根鞘内注射组患者治疗后VAS评分及直腿抬高角度的改变更明显,差异有统计学意义(P0.05);MED神经根鞘内注射组患者治疗后恢复正常工作时间明显短于MED组患者(P0.05);MED神经根鞘内注射组患者出现2例并发症,发生率6.7%,术中硬脊膜撕裂并出现脑脊液漏1例,术后因侧隐窝减压不充分和瘢痕粘连再手术1例;MED组患者出现切口感染1例,发生率为3.3%(P0.05)。结论后路脊柱显微内镜结合鞘内注射类固醇激素治疗腰椎椎间盘突出,能显著改善术后疼痛、恢复肢体活动范围及更早的恢复日常生活。     

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.