经后路椎管内椎间盘镜治疗钙化型腰椎间盘突出症

目的：介绍经后路椎管内显微内窥镜椎间盘切除手术系统（MED）治疗钙化型腰椎间盘突出症。方法：1999年6月－8月用MED治疗钙化型腰椎间盘突出症21例。详细介绍了手术过程、操作技巧及手术适应证。结果：全部患者术后无并发症。平均随访16．1个月,按Nakal疗效评定分级属优14例、良4例、可3例,优良率为85．7％。结论：严格掌握适应证、娴熟操作技巧是钙化型腰椎间盘突出症行MED治疗成功的关键。     

运用电动磨钻在椎间盘镜下切除钙化型腰椎间盘突出17例报告

目的介绍电动磨钻经后路椎间盘镜下椎间盘切除术（MED）治疗钙化型腰椎间盘突出的手术方法，并总结其治疗结果。方法2003年6月-2005年1月采用电动磨钻经脊柱后路MED治疗钙化型腰椎间盘突出并与相邻椎体上、下缘形成骨桥的患者17例。结果随访5—18个月，平均8．6个月。参照Nakal评定标准，优良率为94．2％。结论电动磨钻经椎间盘镜下腰椎间盘摘除术治疗钙化型腰椎间盘突出症有较好的效果。     

脊柱后路显微内窥镜下手术治疗腰椎间盘突出症与腰椎管狭窄症86例报告

目的：探讨在脊柱后路显微内窥镜下微创手术治疗腰椎间盘突出症及腰椎管狭窄症的效果。方法：对86例腰椎间盘突出症和合并腰椎管狭窄症患者采用脊柱后路显微内窥镜下髓核切除术并椎管减压术治疗。结果：术后症状，体征安全消失68例。基本缓解12例，优良率94%，结论：脊柱后路显微内窥镜下可完成腰椎间盘突出合并腰椎管狭窄症的治疗，但巨大中央型突出并钙化者不适合在后路显微内窥镜下操作。     

脊柱后路显微内窥镜下手术治疗腰椎间盘突出症的临床应用

目的 探讨脊柱后路显微内窥镜下椎间盘切除术(MED)治疗腰椎间盘突出症的临床效果和应用价值。方法 自1999年9月～2002年10月，对腰椎间盘突出症152例患者采用椎板间隙入路显微内窥镜下椎间盘切除术治疗，随访观察临床疗效。结果 113例获得3～19个月随访，按Macnab疗效评定标准，优86例，良21例，可4例，差2例，手术优良率94．6％。结论 只要掌握好适应证，应用椎板间隙入路显微内窥镜下椎间盘切除术治疗腰椎间盘突出症具有创伤小、术后恢复快、手术安全性好等优点，疗效可靠。     

42例椎间盘镜下髓核摘除术早期疗效

目的：探讨椎间盘镜下腰椎间盘髓核摘除术的手术要点和早期疗效。方法：显微内窥镜椎间盘切除术(microendoscopic discectory,MED)在椎间盘镜直视下对42例单间隙腰椎间盘突出症患者行突出髓核摘除术，并进行疗效分析。结果：42例获随访，时间3—24个月(平均10个月)。疗效优38例，良3例，可1例。无差级疗效及相关并发症发生。结论：椎间盘镜下腰椎间盘髓核摘除术创伤小，患者术后恢复快，疗效肯定，是治疗腰椎间盘突出症的有效方法之一。     

显微内窥镜下手术治疗腰椎间盘突出症

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技术要点及临床效果。方法：回顾分析采用MED治疗的230例腰椎间盘突出症患者的临床资料及治疗效果并与接受传统手术患者的疗效进行分析比较。结果：随访182例，优良率91.7%。与传统手术方法比较，临床效果略好，但无显著差别。结论：采用MED治疗损伤小，恢复快，是传统手术的微创化。     

经脊柱后路显微内窥镜腰椎间盘摘除术（附30例报告）

目的：本报告经脊柱后路显微内窥镜腰椎间盘除术（Microendoscopic Discectomy MED)治疗腰椎间盘突出症,方法：对30例腰椎间盘突出症患行脊柱后路显微内窥镜下腰椎间盘掊除和侧隐窝扩大术,术中用C型臂X线机定位,在荧屏监视显微内窥镜下切除纤维环,除突出的椎间盘组织,咬除肥厚的黄韧带,扩大侧隐窝,对神经根彻底减压。结果：近期随访3-5个月,优良28例,优良率93%,无并发症发生。结论：经脊柱后路显微内窥镜腰椎间盘除术,技术先进,创伤小,出血少,恢复快,疗效肯定。     

后路显微内窥镜（METRx^TM）下钙化型腰椎间盘突出症的治疗

目的探讨经后路显微内窥镜椎间盘切除手术系统（MED）治疗钙化型腰椎间盘突出症的适应证选择及手术技巧。方法2000年12月至2008年6月,使用后路显微内窥镜系统治疗钙化型腰椎间盘突出症25例,详细介绍了手术过程、手术适应证及操作技巧。治疗组钙化型腰椎间盘突出症与一组单纯腰椎间盘突出症MED手术组进行手术时间、术中出血量、术后住院时间、术后下地活动时间、恢复日常生活时间及住院费进行术后短期项目比较。结果术后短期疗效评价依照Nakai分级,优良率91．7％。治疗组有2例脑脊液漏,其中1例转为开放手术,余无严重并发症。钙化型腰椎间盘突出症与单纯腰椎间盘突出症组比较除手术时间和术中出血量差异有统计学意义（P〈0．05,P〈0．01）外,其余项目均无统计学意义（P〉0．05）。治疗组行腰、腿疼平均目测视觉类比评分法（VAS评分）显示术前与术后3、6、12个月明显下降。Oswestry功能指数（ODI）术前与术后3个月比较,从术前平均45．6降至术后22．4（P〈0．01）。结论对钙化型腰椎间盘突出类型进行分类,术前评估,严格掌握适应证,熟练操作技巧是钙化型腰椎间盘突出症行MED治疗成功的关键。     

脊柱后路显微内窥镜手术治疗中央型腰椎间盘突出症

目的：介绍经脊柱后路显微内窥镜椎间盘切除术系统(MEDII/METRX)治疗中央型腰椎间盘突出症。方法：1999年12月一2002年2月用metrx治疗中央型腰椎问盘突出症48例，详细介绍了手术过程，设计“L”形凿刀进行切除的操作技巧及手术适应证。结果：平均随访16．5个月，按Nakal疗效评定分级：优39例，良7例，可1例，差1例；优良率95．8％。结论：完善的器械、娴熟的操作技巧、预防性止血是中央型腰椎间盘突出症行MED治疗成功的关键。     

急诊内窥镜下椎间盘切除术治疗重症腰椎间盘突出症

重症腰椎间盘突出症系椎间盘突出或脱垂压迫马尾神经及神经根，导致大小便功能障碍、鞍区麻木、剧烈腰腿痛、活动困难等，常需急诊手术治疗。我院于2002年1月．2003年6月，应用后路显微内窥镜下髓核摘除术(microendoscopic discectomy．MED)治疗腰椎间盘突出症358例，其中43例为合并马尾神经压迫的重症腰椎间盘突出症，急诊行MED，获得满意效果，报告如下。     

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.     

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.     

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.