寰枢椎失稳的研究进展

寰枢椎是构成头颅旋转运动的重要结构，其稳定性主要依赖于本身骨性结构的完整性及位于齿状突后方的横韧带和翼状韧带的连续性。外伤、炎症、先天性畸形均可引起寰枢椎解剖关系上的紊乱，而导致寰枢椎失稳，若处理不及时，随时可发生压迫脊髓的危险，甚至危及生命。有作者把上颈椎不稳对脊髓存在的潜在危险，称之为上颈椎危象。近年来国     

寰枢椎后路融合术

寰枢椎后路融合术党耕町王超寰枢椎的畸形、损伤、炎症和肿瘤可使正常解剖结构出现异常，失去稳定性，使上部颈脊髓处于危险状态。在外力作用下出现急性脊髓损伤，危及生命，也可以渐进性发展形成慢性高位颈脊髓病。寰枢椎不稳通常需做寰枢椎融合术。寰枢椎融合术分为侧前...     

枕颈部外科临床研究的过去、现在和将来

正枕寰枢椎连接是具有高度灵活性的解剖结构,临床上通常称为枕颈部结构,有其特征性的生物力学功能,其活动幅度占整个颈椎屈伸及旋转活动的50%。枕寰复合结构包括前寰枕膜、后寰枕膜和两侧的寰枕关节。枕寰关节由寰椎侧块的上关节面和枕骨髁构成,成马鞍状,属于滑膜关节,并与枢椎连接形成完整的解剖结构及生物学功能单位。因此,许多因素都可能导致枕颈部结构稳定功能丧失,在脊柱外科领域,枕颈部外科越来越受到临床     

寰枢椎后路内固定技术的研究进展

寰枢椎不稳多采用后路手术治疗,但由于其解剖及生物力学上的特殊性,内固定方式也与下颈椎明显不同,目的是提供即刻稳定性,解除脊髓及神经压迫,促进融合。目前固定方式主要包括钢丝固定技术、椎板夹或椎板钩技术、Magerl技术、寰椎侧块螺钉技术及椎弓根钉技术、枢椎椎弓根钉、枢椎椎板螺钉、峡部螺钉等,其后又出现寰椎后弓螺钉、后弓锁定钛板、寰枢侧块关节间融合器等新技术,但各固定方式在技术及恢复上颈椎稳定性上存在优缺点,故熟悉各内固定技术并对该领域研究进展有所了解有极其重要的意义。     

后路植骨APOFIX内固定治疗创伤性寰枢椎不稳

创伤性寰枢椎骨折脱位导致的寰枢椎关节不稳。是临床上常见的上颈椎损伤，早期可伴脊髓损伤，或随着病程进展最终出现神经根刺激和脊髓压迫症状。使用Apofix内固定系统治疗此类损伤具有操作简单、固定可靠、植骨块愈合率高等优点。我们自1998年5月-2002年12月收治创伤性寰枢椎不稳31例，其中18例采用此方法治疗，疗效满意，现报道如下。     

后路寰枢椎椎弓根钉内固定及枕颈融合术治疗上颈椎不稳27例临床分析

目的 探讨应用寰枢侧块螺钉与枢椎椎弓根钉内固定及枕颈融合术治疗上颈椎不稳的疗效.方法 对寰枢椎不稳27例患者采用寰椎侧块螺钉结合枢椎椎弓根螺钉及枕颈融合治疗.结果 27例患者均经寰枢椎螺钉或枕颈融合内固定术,其中一例颅底凹陷患者一期行经口齿状突切除术,二期行枕颈融合术,27例患者无一例发生脊髓和椎动脉损伤.所有患者均获得随访,随访3 ～17个月,平均9个月.术后3个月JOA评分13.5 ～16.9分,平均15.2分,改善率为88.4％.植骨块全部融合,无内固定断裂、松动.结论 后路寰椎侧块螺钉结合枢椎椎弓根螺钉固定及枕颈融合术具有稳定的三维固定效果,可用于治疗上颈椎不稳.     

经寰椎侧块枢椎椎弓根钉棒系统治疗寰枢椎不稳

寰枢椎不稳可以逐渐形成高位颈脊髓压迫，还可能在外力作用下导致急性脊髓损伤，危及生命。因此，临床上处理寰枢椎不稳主要采用固定融合术。后路经关节寰枢椎块螺钉（Magerl术）是目前国内外比较推崇的术式。特别是Magerl螺钉复合Gallie钢丝固定，     

老年寰椎骨折的诊断与治疗进展

正寰椎即第一颈椎(C_1),寰椎骨折被认为是摔倒或其他偶然因素导致寰椎过度伸展或纵向挤压暴力导致的结果~([1])。寰椎骨折约占成人颈椎骨折总数的11%~([2-3])。在解剖结构上,寰椎无棘突和椎体,呈环形,由2个侧块组成,并由前、后弓相连。枕骨、寰椎和枢椎通过韧带结构和滑膜直接连接,为上颈椎提供了重要的稳定性。寰枢横韧带是寰枢关节的主要稳定结构,其主要功能是防止齿状突向脊髓后移和寰枢椎脱位。     

枢椎经椎板螺钉联合寰椎侧块螺钉内固定术的临床应用

目的 探讨后路经枢椎椎板螺钉联合寰椎侧块螺钉固定技术治疗上颈椎不稳的临床疗效和并发症.方法 2003年10月至2006年12月,采用此技术治疗寰枢椎不稳17例,男12例,女5例;年龄34～73岁,平均42.5岁.Anderson Ⅱ型和Ⅲ型齿突骨折14例,寰椎横韧带断裂1例,先天性游离齿突并寰枢椎不稳2例.均有寰枢椎半脱位或不稳,表现为不同程度的颈枕区疼痛,活动受限.枢椎经椎板螺钉固定技术以棘突和椎板的交界处椎板头尾方向的中点为进钉点,为避免钉道的相互干扰,第1枚螺钉的进钉点通常选择枢椎椎板的偏头侧,另1枚螺钉的进钉点偏尾侧,用高速磨钻在进钉点磨去少许皮质骨开窗后,用手钻向枢椎对侧椎板钻孔,螺钉方向在直视下与椎板平面并行,并稍向枢椎椎板背侧倾斜,以确保螺钉不穿破椎板腹侧皮质侵犯椎管,宁可穿破枢椎椎板背侧皮质骨.内固定系统均使用颈椎后路Vertex钉棒系统同定.结果 术中无一例发生脊髓和椎动脉损伤.有2例患者在剥离寰椎后弓下缘时,损伤静脉丛,用明胶海绵压迫止血成功.术后CT示枢椎椎板螺钉位置良好,未见侵犯枢椎椎管和脊髓.随访术后X线片未见明显颈椎不稳、内固定失败及螺钉松动退出.结论 枢椎后路经椎板螺钉技术固定牢固,操作简单,相对安全,值得进一步推广.     

改良后路寰枢椎经关节螺钉固定融合术治疗寰枢椎不稳

寰枢椎不稳可导致高位颈脊髓压迫,甚至在外力作用下出现急性脊髓损伤,危及生命.因此,一旦明确诊断,应尽早手术复位和固定.解除颈脊髓压迫,维持上颈椎的稳定.自2005年4月～2009年11月笔者采用改良后路寰枢椎经关节螺钉(Magerl技术)固定融合术治疗寰枢椎不稳12例,取得较好效果.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.     

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.     

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.