人工椎间盘的研究进展

椎间盘突出症等脊柱退行性疾病是骨科的常见病、多发病．手术是主要的治疗方法之一。脊柱手术后．通常需要进行脊柱生物力学重建．以防止手术引起的脊柱不稳等并发症。椎体间融合手术是临床广泛应用的脊柱生物力学重建方法之一，临床观察发现，椎间融合手术近期疗效好．但存存植骨块吸收、不融合、相邻节段椎间盘退变加速等问题。人们在对椎间融合手术不断改进的同时．正在努力寻找更合理的生物力学重建方法。     

腰椎融合术的研究现状

椎间融合是脊柱外科应用最广泛的技术之一.1911年Hibbs和Albee首次介绍脊柱融合术的稳定性,Mercer于1936年提出脊柱融合理论,该观点逐渐被广大的脊柱外科医师所接受.腰椎椎间融合术主要应用于治疗腰椎退变性不稳、腰椎管狭窄症、腰椎滑脱症、脊柱侧弯及椎间盘源性疼痛等疾病.根据手术入路不同分为不同术式,手术由原来大切口开放性手术转化为小切口或经皮借助于特殊工作通道的微创手术,本文就不同的腰椎椎间融合方法总结如下.     

微创经椎间孔腰椎椎间融合术的优势及存在的问题

椎间融合由于具有稳定脊柱前中柱的生物力学优势而成为腰椎融合的主要术式.根据手术入路不同,腰椎椎间融合可以分为前路腰椎椎间融合术(ALIF)、后路腰椎椎间融合术(PLIF)和经椎间孔腰椎椎间融合术(TLIF)等3种方法.TLIF是近十年来发展的新的椎间融合技术,与PLIF相比,可减少医源性神经损伤、获得环行融合和避免传统脊柱前方显露的相关并发症.然而,采用传统开放性TLIF常会造成肌肉广泛损伤,从而导致患者术后出现腰部不适或其他并发症,影响手术长期疗效.     

后路腰椎椎体间融合与经椎间孔腰椎椎体间融合治疗退行性腰椎滑脱与不稳疗效比较

目的比较后路腰椎椎体间融合(PLIF)与经椎间孔腰椎椎体间融合(TLIF)手术治疗退行性脊柱滑脱与不稳的疗效。方法 162例退行性脊柱疾病患者中,86例行PLIF术,76例行TLIF术。比较两组手术时间、出血量,观察术前术后滑脱复位、椎间隙及椎间孔高度变化,使用ODI、VAS评分方法对患者术前术后情况进行评估,按照影像学Brantigan和Steffee标准评价植骨融合情况,同时记录并发症及其转归。结果与PLIF组比较,TLIF组手术时间短、失血量少、手术并发症少(P<0.05),而滑脱复位、椎间隙及椎间孔高度变化、ODI、VAS评分、ODI改善率、植骨融合率无明显差别(P>0.05)。结论 PLIF与TLIF均为手术治疗退行性脊柱滑脱与不稳的有效方法,而TLIF手术时间短、失血量少,并发症少。     

椎体间内固定钉在脊柱损伤中的应用

采用脊柱前路手术配合椎体间内固定钉一次完成椎板减压、畸形矫正、椎间植骨融合和内固定,治疗脊柱损伤并重建脊柱稳定性.36例中31例获1年以上随访,不全性截瘫24例神经功能获Ⅱ级以上恢复;后凸畸形矫正10°～26°者30例.文中讨论了手术适应症、手术方法,并探讨该型脊柱内固定器材的优缺点.     

微创腰椎椎间融合技术及其临床应用进展

腰椎椎间融合术是治疗腰椎退变性不稳、滑脱及椎间盘源性疼痛的经典手术方法。传统腰椎椎间融合手术需要广泛剥离及长时间牵拉肌肉,容易引起软组织损伤。椎旁肌肉的病理改变是腰椎融合术后腰部力量减弱及慢性腰痛发生的主要原因[1]。近年来,随着脊柱外科微创技术的迅猛发展,用于腰椎椎间融合的微创技术应运而生,使脊柱融合的方式发生了很大的变化,并对传统的融合观念提出了新的挑战。微创腰椎融合技术是在取得优于或不低于开放腰椎融合术效果的同时,减少对椎旁软组织的损伤,同时患者术中出血少,术后疼痛轻、恢复快,有利于患者的早日康复。根据手术入路不同,微创腰椎椎间融合可分为前路腰椎椎间融合（anterior lumbar interbody fusion, ALIF）、后路腰椎椎间融合（posterior lumbar interbody fusion, PLIF）、经腰椎椎间孔椎间融合（transforaminal lumbar interbody fusion, TLIF）、经皮经骶前轴向腰椎椎间融合（axial lumbar interbody fusion, AxiaLIF）和极外侧入路椎间融合（extreme lateral interbody fusion, XLIF）等。现就上述微创腰椎椎间融合方法及其相关问题作一综述。     

极外侧椎间融合术的研究进展

近年来微创技术的出现,是脊柱外科适应现代技术发展的产物,微创化手术已逐渐成为脊柱外科发展的趋势。椎间融合由于具有稳定脊柱前中柱的生物力学优势而成为腰椎融合的主要术式。目前微创化腰椎融合的主要术式有:前路腰椎椎间融合术(anterior lumbar interbody     

小关节分级切除在经椎间孔入路椎间融合术的临床应用

目的 探讨小关节分级切除应用于经椎间孔入路椎间融合术的临床疗效.方法回顾分析本组应用自外而内的小关节分级切除、实施经椎间孔入路椎间融合手术的57例患者.通过影像学手段、疼痛视觉模拟量表（visual analog scale,VAS）评分、中华骨科学会脊柱学组腰背痛手术评分标准评估患者术前、术后及随访时的情况,并进行统计学分析.结果所有患者无内固定松动、脱落、移位等并发症发生;术后1例出现切口感染,抗感染治疗2周后痊愈;VAS评分改善明显（P〈0.05）;按中华骨科学会脊柱学组腰背痛手术评分标准,手术优良率为93%.所有患者术后3个月均达到骨性融合.结论 在一定适应证下,自外而内的分级切除小关节的减压方案用于经椎间孔入路椎间融合术是可行、安全、有效的.     

微创可扩张通道辅助腰椎融合术之管见

 建立一个可以到达手术部位的微创工作通道是进行脊柱微创手术的前提条件, 从经皮穿刺针管、经皮切吸工作套管、椎间孔镜及椎间盘镜下腰椎间盘切除术(microendoscopic discectomy, MED)工作通道到 X-Tube、Mast Quadrant, 微创工作通道技术得到迅速发展, 变得更加灵活多样, 脊柱微创手术也从早期的椎间盘介入手术发展到微创椎间融合及内固定手术。     

腰椎融合术的治疗进展

腰椎融合术在治疗腰椎管狭窄、退变性椎体滑脱、脊柱侧凸、退变性椎间盘疾病中得到广泛的应用.随着脊柱外科技术和内固定器器械发展,腰椎融合术有了很多方法.开放手术有椎体间融合,包括前路椎间融合术(anterior lumbar interbody fusion,ALIF)、后路椎间融合术(posterior lumbar interbody fusion,PLIF)、经椎间孔椎间融合术(transforaminallumbar interbody fusion,TLIF);脊柱后外侧融合术(posteriorlateral fusion,PLF);微创方法有应用内窥镜、特殊显露器械或经皮入路完成腰椎前、后路融合固定术.现综述如下.     

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.     

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.