乙状窦后入路显微手术切除大型听神经瘤

目的探讨乙状窦后入路显微镜下切除大型听神经瘤的手术方法及临床意义。方法采用乙状窦后入路显微手术切除，对手术入路、显微手术技巧、手术后处理及并发症防治进行系统分析。结果临床应用15例，其中肿瘤全切除12例，次全切除3例，面神经解剖学保留13例，耳蜗神经解剖学保留6例。术后短期并发症3例，无死亡病例。结论乙状窦后入路显微镜下切除大型听神经瘤是安全的手术方法，对脑组织结构的创伤小，利于提高肿瘤全切除率并有效保护面神经和听神经的功能。     

小切口开颅显微技术治疗继发性三叉神经痛

目的探讨小切口开颅显微技术切除桥小脑角区肿瘤治疗继发性三叉神经痛的效果。方法 2010年1月~2012年12月采用小切口开颅显微技术治疗30例继发性三叉神经痛。采用枕下乙状窦后小切口开颅技术,在显微镜下沿小脑半球外侧面逐步进入,显露桥小脑角池,探查颅神经与肿瘤的关系,继而全/近全切除肿瘤,彻底解除三叉神经根区压迫。结果术后三叉神经痛症状均消失,其中29例术后症状立即消失,1例术后1个月内逐渐消失。24例(80.0%)肿瘤全切除,6例胆脂瘤次全切除囊壁。面神经功能保留27例(90.0%),有效听力保留28例(93.3%)。30例随访3~24个月,中位数10个月,无复发。结论小切口开颅技术切除桥小脑角区肿瘤治疗继发性三叉神经痛安全有效。     

神经内镜辅助显微手术治疗脑桥小脑角病变

目的探索神经内镜辅助显微手术治疗脑桥小脑角病变的实用性及其优势。方法对38例脑桥小脑角病变采取乙状窦后入路神经内镜辅助显微手术治疗。结果10例听神经瘤全切并面神经保留，22例胆脂瘤及1例脑膜瘤全切除，5例三义神经痛术后发作性疼痛消失。无术后并发症及死亡。结论经乙状窦后入路神经内镜辅助显微手术治疗脑桥小脑角病变，有利于提高手术疗效，降低手术危险性。     

神经内镜辅助锁孔显微外科治疗颅内胆质瘤

目的 探讨神经内镜辅助锁孔显微神经外科治疗颅内胆质瘤的方法和意义。方法 应用神经内镜辅助锁孔显微神经外科技术治疗颅内胆质瘤16例。以MRI显示的肿瘤核心部位选择锁孔入路，在手术显微镜下尽可能切除可见的肿瘤部分，再辅助使用神经内镜寻找残余的肿瘤并切除。结果 在常规显微神经外科切除肿瘤后，应用神经内镜探查，13例仍能发现残余肿瘤，在内镜下进一步切除；3例无残余肿瘤；肿瘤全切除14例，次全切除2例。15例手术后2周内原有症状明显缓解或恢复，1例发生了无菌性脑膜炎，经治疗2周后痊愈。无术后脑积水及继发性颅内出血。术后3～12个月随访10例，9例痊愈，1例存在三叉神经痛，需药物治疗。结论 神经内镜辅助锁孔显微神经外科治疗颅内胆质瘤，尤其是生长广泛的巨大胆质瘤，有助于提高颅内肿瘤全切率，减少手术创伤，降低术后并发症。     

第四脑室肿瘤的显微手术治疗

目的探讨第四脑室肿瘤的显微手术方法. 方法 2000年1月～2003年6月我院对29例第四脑室肿瘤采用显微手术治疗,5例因肿瘤侵犯上蚓,瘤体接近皮层部采用小脑蚓部入路,余24例均经小脑延髓裂入路,显微手术切除肿瘤. 结果肿瘤全切除23例,次全切除6例.术后并发症:上消化道出血2例,小脑缄默征1例,第四脑室血肿1例,远隔部位硬膜外血肿1例,呼吸不规则1例.19例随访3～12个月,平均5.5月,肿瘤无复发. 结论术前正确判断肿瘤性质及其基底部所在位置,选择适当的手术入路,熟练掌握第四脑室的显微解剖是手术成功的关键.     

大型听神经瘤的显微手术

目的 报道大型听神经瘤显微手术切除、面神经解剖保留及功能恢复的临床效果.方法 采用枕下乙状窦后入路切除大型听神经瘤82例,并将术后面神经功能HB分级为Ⅲ～Ⅵ级者随机分为2组,分别予Kabato康复训练和常规治疗,对其临床资料进行回顾性总结.结果 肿瘤全部切除77例(93.9%),次全切除5例.面神经解剖保留78例(95.1%),术后训练组面神经功能恢复较快,且显效率和有效率均明显高于非训练组.随访6个月～3年,次全切除5例中复发2例,3例患者出现慢性头痛,无长期昏迷、死亡病例.结论 全切除肿瘤的同时保留面神经功能,是大型听神经瘤显微手术的目标.     

枕下-乙状窦后入路显微手术切除大型听神经瘤

目的 探讨经枕下-乙状窦后入路显微手术切除大型听神经瘤的临床疗效和意义。方法 采用枕下乙状窦后入路对49例大型（≥4 cm）听神经瘤行显微手术切除,单侧枕下乳突后“S”形皮肤切口,铣刀骨瓣成形,显微镜下行肿瘤囊内逐步切除,最后分离内听道部分,锐性剥离面神经上残存肿瘤。术前及术后分别进行面神经和听神经的功能评估。结果 肿瘤全切除45例（92%）,次全切除4例（8%）,全组无死亡病例。面神经解剖保留42例（86%）,术后2周功能保留36例（73%）;听神经解剖保留7例（14%）,术后2周功能保留3例（6%）。1例手术区血肿再手术清除。37例随访0.5～5年,平均2.8年,肿瘤无复发,均参加正常工作和学习。结论 枕下乙状窦后入路显微手术是切除大型听神经瘤的较好方法,肿瘤的全切率高,死亡率和病残率低,并能有效地保留面、听神经的功能。     

枕下乙状窦后入路显微手术切除听神经瘤

目的总结枕下乙状窦后入路切除听神经瘤的临床经验。方法采用单侧枕下乙状窦后入路,运用显微外科技术切除听神经瘤71例,其中17例采用内窥镜辅助小骨窗(3.0cm×3.5cm)手术。结果肿瘤镜下全切除63例(88.7%),次全切除8例(11.3%)。面神经解剖保留54例(76.1%),功能保留37例(52.1%),有效听力保留2例(2.8%),无手术死亡。结论经枕下乙状窦后入路显微手术治疗听神经瘤,能获得对听神经瘤及桥小脑角的良好显露,手术效果满意。     

内镜辅助经鼻蝶入路至斜坡区的显微手术

目的 探讨内镜辅助经鼻蝶入路至斜坡区的显微手术方法和疗效.方法 根据经鼻蝶入路至鞍区斜坡区显微解剖学研究结果,采用内镜辅助经鼻蝶显微手术治疗该区肿瘤12例(侵袭性垂体腺瘤8例,脊索瘤3例,软骨瘤1例).所有病例均在3个月至6年内获得随访.结果 手术全切8例,次全切除3例,部分切除1例.术后发生短暂性尿崩症6例,脑脊液鼻漏2例,无死亡及颅内感染.随访3个月至6年,除1例脊索瘤残瘤继续生长外,其余患者未见肿瘤复发.结论 采用经蝶入路显微手术切除沿中线生长的鞍区斜坡区肿瘤,入路简便快捷,创伤小,手术显露良好,疗效满意.内镜辅助使得经蝶入路更为安全、有效.     

显微手术切除颅底沟通性脊索瘤

目的 探讨不同颅面入路治疗颅底沟通性脊索瘤的入路选择和显微手术方法.方法 手术治疗并经病理证实的颅底沟通性脊索瘤22例.采用颅面入路或联合入路显微手术切除,包括扩大的前颅底入路8例,改良Weber-Ferguson入路8例,下颌入路6例.其中部分向颅内生长明显的沟通性肿瘤,联合经颅手术,包括翼点入路3例,颞颧入路1例,枕下乙状窦后入路2例.对患者预后进行长期随访.结果 肿瘤全切除10例,次全切除7例,大部切除4例,部分切除1例.肿瘤全切除或次全切除占77.3%.术后无死亡和严重神经功能障碍患者.术后脑脊液漏1例,伤口感染1例,动眼神经不全麻痹2例,展神经麻痹1例.本组中20例进行了随访,随访1～10年,平均3.4年.恢复正常工作或部分工作12例,不能工作但能生活自理5例,生活不能自理1例,死于肿瘤复发2例.结论 颅底沟通性脊索瘤侵犯范围广泛,应争取手术尽可能全切.根据肿瘤的不同部位和生长方向,选择不同入路或联合入路.显微外科手术可提高切除率、降低并发症,同时应注意硬脑膜的修补和颅底的重建.     

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.     

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.     

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.     

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.     

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.