同种异体骨修复良性骨肿瘤及瘤样病变骨缺损

背景：骨肿瘤及瘤样病变切刮后骨缺损取自体骨填充，由于取材量不能完全满足临床需要，且供骨区常遗有不同程度并发症，使其在临床应用中受到明显限制。异体骨以其结构及生物特性与自体骨相似、来源丰富、可以长期保存及使用方便等特点日益广泛地应用于临床。 目的：观察同种异体骨用于填充修复良性骨肿瘤及瘤样病变切、刮除术后骨缺损后的生物相容性表现及临床应用效果。 设计：回顾性分析。 单位：内蒙古医学院第二附属医院骨肿瘤科、骨盆外科。 对象：选择1999-12/2005-12在内蒙古医学院第二附属医院骨肿瘤科因良性骨肿瘤及瘤样病变行病灶刮除、高温灭活，冻干同种异体小块骨填充修复骨缺损的患者230例，男156例，女74例；年龄5~56岁。患者同意使用异体骨，并签订植入异体骨协议书；实验经医院伦理委员会批准。 方法：①使用由由山西奥瑞生物材料有限公司/山西省医用组织库提供的同种异体骨填充修复骨缺损。对良性骨肿瘤及骨囊肿和骨纤维结构不良等行囊内刮除术，用同种异体骨填塞空腔。②根据Mankin等对同种骨移植结果的评分标准评估疗效，分为满意和不满意两个层次。于术后3，6和12个月对手术部位拍摄X射线平片，并平均随访38个月以观察疗效。 主要观察指标：异体骨填充修复骨肿瘤骨缺损的组织相容性。 结果：患者230例全部进入主要结果分析。①同种骨生物相容性：少数患者术后有轻度排异反应。该植入材料生物相容性好，可与植入部位患者骨组织直接进行融合，不阻止骨细胞在其表面的正常活性或干扰自体骨细胞的自然替代过程，即无免疫排斥反应或很小。所有病例在术后6~18个月达到骨性愈合，平均6.5个月。并发症：34例切口渗出淡黄色液体，其中30例于2周后切口愈合（14.8%）；切口延期愈合4例（1.7%）。②疗效：满意196例（85.2%），不满意34例（14.8%）。 结论：同种异体小块骨具有良好的组织相容性及成骨作用，是骨移植术中良好的植骨材料。     

同种异体骨材料复合自体浓缩红骨髓移植治疗良性骨肿瘤和瘤样病变

背景：同种异体骨是临床常用的骨移植材料,但缺乏诱导成骨能力是最大的问题。 目的：评价良性骨肿瘤及瘤样病变刮除或切除后应用同种异体骨复合自体红骨髓修复骨缺损的效果。 设计、时间及地点：回顾性病例对比分析,于2004-05/2006-05在华中科技大学同济医学院附属同济医院骨科进行。 对象：选择良性骨肿瘤及瘤样病变108例患者,男 58例,女 50例;年龄10~58岁,平均32岁。其中采用异体骨复合自体浓缩红骨髓植骨52例(复合红骨髓植骨组);单纯异体骨植骨56例(单纯植骨组)。 方法：复合红骨髓植骨组患者根据预计植骨量从每位患者两侧的髂前上棘或髂后上棘抽取红骨髓40~100 mL,在植骨前将同种异体骨与红骨髓充分混匀。肿瘤刮除或切除后,用电刀烧灼骨缺损腔,将同种异体骨剪成细小的短棒状或修成2 mm见方的块状,植入骨缺损区内。单纯植骨组将相同比例的生理盐水与同种异体骨充分混匀后植入骨缺损区内。 主要观察指标：术后定期进行植骨区X射线检查及骨密度检测,比较两组间移植骨颗粒界限模糊、消失的时间及不同时间骨密度的情况。同时观察术后并发症如免疫排斥反应、感染等发生情况。 结果：100例患者达骨性融合(复合红骨髓植骨组49例,单纯植骨组51例),并获得24个月随访,数据进入结果分析。复合红骨髓植骨组移植骨界限模糊时间和消失时间均短于单纯植骨组(P < 0.05~0.01)。术后3,6,12个月时复合红骨髓植骨组骨密度高于单纯植骨组(P < 0.05~0.01)。复合红骨髓植骨组2例,单纯植骨组3例出现排异反应,使用免疫抑制剂治疗两三周后痊愈。 结论：同种异体骨复合自体红骨髓来源相对丰富,抗原性减弱,能明显促进骨融合和骨缺损的愈合。     

Osteoset人工骨加自体骨移植治疗胸腰椎脊柱结核：与自体骨移植的比较

目的：分析病灶彻底清除后Osteoset人工骨加自体骨移植联合内固定治疗脊柱结核的安全性、可行性和治疗效果，并与单纯使用自体骨植骨比较。 方法：①实验对象：2003-01/2005-11在四川大学华西医院骨科手术治疗的脊柱结核患者124例，随机选择40例胸腰椎脊柱结核患者进行分析，对治疗和实验均知情同意。②实验材料：Osteoset-T人工替代骨: 由美国瑞特（Wright）医疗技术公司生产的骨移植替代材料。③实验方法：实验组20例，病灶彻底清除后带妥布霉素的Osteoset人工骨加自体骨植骨内固定；对照组20例，病灶彻底清除后单纯自体骨植骨内固定。④实验评估：根据术前、术后、术后3个月、术后6个月、术后12个月患者脊柱X射线正侧位片及CT扫描对两组患者的骨融合和畸形矫正情况进行评定和分析。 结果：①患者平均住院19.5 d（12～27 d）。所有患者术后伤口均一期愈合，无全身并发症状，术后1周平均白细胞计数8.2×109。②随访12～48个月，平均26个月。影像学资料提示钢板位置良好，内固定无松动；结核病灶均无复发，脊柱后凸畸形平均矫正Cobb角15°，畸形矫正角度没有丢失。③Osteoset人工骨加自体骨植骨术后3个月融合率为40%（8/20）；术后6个月融合率为85%（17/20）,单纯自体骨植骨术后3个月融合率为10%（2/20例），术后6个月达55%（11/20）。术后1年两组的融合率均为100%。 结论：Osteoset人工骨在胸腰椎脊柱结核骨融合术中可以补充植骨量,与单纯使用自体骨植骨相比达到骨性愈合的时间较短。     

不同种类骨移植后路矫治青少年特发性脊柱侧凸

背景：同种异体骨被广泛应用于脊柱侧凸后路手术,大量研究显示同种异体骨移植与自体髂骨移植可取得相近的临床效果。 目的：观察不同种类骨移植材料在青少年特发性脊柱侧凸后路矫形植骨融合中的临床应用效果。 设计、时间及地点：回顾性对比分析,病例来自2000-01/2005-12华中科技大学同济医学院附属协和医院骨科。 对象：选择行后路钉-棒系统矫形手术且具有完整随访资料的71例青少年特发性脊柱侧凸患者,其中自体骨移植组21例,同种异体骨移植组23例,自体骨混合同种异体骨移植组27例。同种异体骨为冻干同种异体松质骨,由山西省医用组织库提供。 方法：3组骨移植融合手术方法保持一致,按脊柱侧凸类型及后路矫形植骨融合原则进行植骨床准备及植骨。自体骨移植组植入修剪成火柴状的自体髂骨;同种异体骨移植组植入经生理盐水浸泡30~40 min 的冻干同种异体松质骨条;自体骨混合同种异体骨移植组植入髂骨碎块与经上述处理的冻干同种异体松质骨碎块。 主要观察指标：比较术后第3,9,15,36个月的植骨融合率、Cobb角丢失率及各组术后不良反应。 结果：71例患者均进入结果分析。自体骨移植组平均融合节段7个,同种异体骨移植组平均融合节段7.6个,自体骨混合同种异体骨移植组平均融合节段8个。术后第9个月,自体骨移植组融合率高于其他2组(P < 0.05);Cobb角丢失率3组差异无显著性意义(P > 0.05)。术后第3,15,36个月,植骨融合率、Cobb角丢失率3组间差异亦无显著性意义(P > 0.05)。3组均未发生螺钉及棒的松动、断裂、感染等并发症,其中自体骨移植组发生取骨处疼痛3例,自体骨混合同种异体骨移植组发生取骨处疼痛1例。 结论：同种异体骨移植、自体骨混合同种异体骨移植与自体骨移植在青少年特发性脊柱侧凸后路矫形中对维持矫形可取得相近的近远期临床效果。     

自体红骨髓复合自体松质骨填充同种异体皮质骨环重建兔颈椎

背景：国内外不少学者运用异体骨移植椎间融合进行椎体切除与重建,骨融合时间优于单纯自体骨移植,其在融合早期能提供支撑稳定作用,但制备异体骨移植材料时,易破坏基质中的骨诱导因子,不利于骨质生长。 目的：课题创新性设计并验证自体红骨髓复合自体松质骨填充同种异体皮质骨环重建兔颈椎的能力。 设计、时间及地点：随机对照动物实验,于2004-10/2006-03在武汉大学人民医院骨科实验室完成。 材料：健康成年新西兰大耳白兔60只,雌雄不限,体质量2.0~2.5 kg。其中12只兔用于同种异体皮质骨环的制备;剩余48只兔随机分为3组,每组16只。自体红骨髓于髂前上棘穿刺抽取红骨髓;自体松质骨从兔髂嵴处取得三面皮质骨。将自体红骨髓与自体松质骨复合,填充在自制的同种异体皮质骨环中。 方法：3组兔采用第4颈椎切除模拟肿瘤切除模型。联合移植组植入同种异体皮质骨环-自体红骨髓-自体松质骨复合物;自体骨移植组植入自体骨;同种异体皮质骨环移植组植入同种异体皮质骨环 。 主要观察指标：以X射线检查、组织形态学检查、血清碱性磷酸酶及扫描电镜观察各组重建颈椎的效果。 结果：术后8周,联合移植组、自体骨移植组植骨材料与上下颈椎融合,有大量骨痂,同种异体皮质骨环移植组可见少量骨痂生长,融合不牢。各组血清碱性磷酸酶开始均升高,4周时联合移植组、自体骨移植组血清中碱性磷酸酶浓度都高于同种异体皮质骨环移植组(P < 0.01),联合移植组、自体骨移植组血清中碱性磷酸酶浓度差异无显著性意义(P > 0.05)。8周时,3组碱性磷酸酶比较差异无显著性意义(P > 0.05)。组织学观察联合移植组、自体骨移植组形成大量成熟骨基质,骨小梁及骨髓腔。扫描电镜观察示联合移植组、自体骨移植组有大量新骨形成。 结论：联合自体红骨髓+自体松质骨+同种异体皮质骨环移植和自体骨移植均有效地重建颈椎,自体红骨髓与自体松质骨复合填充的同种异体皮质骨环可明显促进同种异体皮质骨环重建椎体的作用,可以作为有效椎体重建材料。     

钛网及同种异体骨植骨结合内固定治疗脊柱结核：23例随访验证

背景：植骨内固定治疗脊柱结核容易出现植骨块滑移、骨折、吸收或突入椎管引起神经症状,从而导致脊柱不稳。钛网为强度非常高的圆桶状,其边缘以锯齿状与椎体接触,具有显著防滑移作用。 目的：探讨钛网植入内固定结合同种异体骨植骨治疗胸腰椎脊柱结核的临床效果。 方法：选择胸腰椎结核患者23例,男12例,女11例,年龄13~55岁。采用一期病灶清除,前和/或后路椎弓根系统置入内固定,钛网及同种异体骨联合应用植入治疗,术后观察伤口愈合、结核中毒症状及神经功能恢复,固定融合及复发情况。 结果与结论：23例患者获得1~3年随访,伤口均一期愈合,结核中毒症状明显改善或消失,神经功能完全恢复,内固定无松动、断裂,植骨无移动、折断、吸收,无后突畸形发生,固定融合情况良好,无结核复发迹象,6~12周带支具下床活动,6个月恢复正常生活及工作。证实脊柱结核病灶一期清除后,应用钛网及同种异体骨植骨结合内固定置入治疗能使脊柱获得即刻及远期的稳定,纠正后凸畸形,促进椎体间植骨融合,是目前治疗脊柱结核的一种安全有效的治疗方法。     

同种异体深冻骨复合骨形态发生蛋白2治疗肱骨骨不连31例★

邵阳市第一人民医院骨科在2002-08/2008-07应用同种异体深冻骨复合骨形态发生蛋白2治疗肱骨骨不连31例。所有患者随访7~29个月，总愈合率91.33%，平均愈合时间8个月，无伤口不愈合，局部红肿现象，无内固定松动，断裂等材料反应。提示同种异体骨复合骨形态发生蛋白2植骨治疗骨不连，无免疫排斥反应、生物相容性好，对促进骨愈合疗效可靠。     

同种异体冻干骨加钛笼在颈前路减压融合术中的应用

目的观察同种异体冻干骨加钛笼结合动力型颈前路钢板在颈椎前路减压融合术后的融合情况。方法对122例颈椎病病人行颈前路减压、钛笼加同种异体冻干骨植骨结合动力型颈前路钢板内固定术。于术前、术后6个月进行日本骨科疗效(JOA)评分,观察神经功能恢复情况;术后6个月、1年观察钛笼植骨融合率及早期沉降率。结果术后对116例随访12~22个月,平均17个月。症状均明显缓解,脊髓功能明显改善;JOA评分由术前的8.6分改善至14.1分。根据Zdeblick标准,术后6、12个月钛笼植骨融合率分别达到92.0%和95.6%,而沉降出现率分别为16.0%和18.6%。无钢板和螺钉松动或断裂现象存在。结论同种异体冻干骨加钛笼作为颈椎前路减压融合手术中的支撑性植骨材料,融合率满意,沉降率低。     

异体皮质骨板不同固定方式的生物力学比较

背景：同种异体骨内固定材料已用于临床，但因为强度小仅用于应力较小的部位，如何提高其固定的强度以扩大应用范围是目前研究的关键。 目的：探讨同种异体皮质骨板采用不同固定方式的强度差异及机制。 设计、时间及地点：体外生物力学实验，于2005-10/2006-03在南华大学生物力学实验室完成。 材料：防腐尸体上取下股骨27根；同种异体骨板制备成110 mm×10 mm×3 mm的骨板45块；骨螺钉90个。 方法：27根股骨制作骨折模型，分为双骨板嵌合组、双骨板骨螺钉组、单骨板骨螺钉组， 9个/组。双骨板嵌合组：用2块大小为110 mm×10 mm×3 mm同种异体皮质骨板嵌合固定。双骨板骨螺钉组：用2块 110 mm×10 mm×3 mm同种异体皮质骨板和5枚骨螺钉固定。单骨板骨螺钉组：用1块110 mm×10 mm×3 mm骨板和5枚骨螺钉固定。 主要观察指标：分别对以上3组进行生物力学实验，测试其压缩、弯曲及扭转刚度和极限载荷。 结果：不同固定方式显示不同的力学特征。双骨板嵌合组的抗压刚度与双骨板骨螺钉组相似，高于单骨板骨螺钉组，但抗弯和抗扭刚度显著高于后两组，差异有统计学意义 （P < 0.05）。双骨板嵌合组压缩、弯曲、扭转极限载荷大于双骨板骨螺钉组（P < 0.05），显著大于单骨板骨螺钉组（P < 0.01）。 结论：同种异体皮质骨板固定的强度与固定方式有关。双板嵌合固定比骨板骨螺钉固定具强度和刚度更大，可满足临床需要。     

腰椎后外侧同种异体骨移植融合后排斥反应6例

同种异体骨是目前临床最常用的骨移植材料，移植后排斥反应已逐渐引起关注。2003-01/2006-04哈励逊国际和平医院骨病科收治的6例腰椎后外侧同种异体骨移植融合术后排斥反应患者，腰椎峡部裂性滑脱患者1例，腰椎间盘突出症患者2例，腰椎管狭窄症患者2例，腰椎压缩骨折患者1例；排斥反应发生时间为移植融合术后3~14 d，平均9.3 d。患者所用的冷冻干燥辐照同种异体松质骨均在灭菌有效期内，由山西奥瑞生物材料有限公司（山西省医用组织库）提供。所有患者均采用综合治疗，即抗生素预防感染+原手术切口植骨取出病灶清除术+病灶持续冲洗引流术。6例患者均在原手术切口植骨取出病灶清除术后2周内，取出引流管和冲洗管，无患者继发感染，无患者因排斥反应导致内固定物取出，未出现由此引起的其他相关症状。     

Diagnostic Difficulties and Treatment Implications

Summary: Differentiation between types of epileptic seizures has been aided in recent years by the introduction of intensive neurodiagnostic techniques and the development of increasingly detailed classification systems. Paradoxically, these developments have not simplified the task of matching the appropriate antiepileptic drug to a particular seizure type. It is reasonable to assume that anticonvulsant drugs will have different effects on different types of seizures, but faulty, circular reasoning can enter the picture if one also assumes that responses of seizures to different drugs signify different seizure types. There are several examples of differential diagnoses that can fall prey to this problem, including the diagnosis between partial seizures with secondary generalization and generalized tonic-clonic seizures, and the diagnosis between complex partial seizures and absence seizures with automatisms, among others. Considerations of etiology in future classification systems can further complicate the problem: should one then choose an anticonvulsant drug on the basis of individual seizure type or on the basis of the type of epilepsy? Ramifications of this issue extend even to the drug approval process. Official sanction is not given for use of a drug for a seizure type not included in the original efficacy studies, even if later scientific evidence shows that seizure type to be related to a type that is included. New trials must be undertaken. These problems arise from how we choose to classify seizures.     

Cognitive Dysfunction Associated with Antiepileptic Drug Therapy

Summary: Epilepsy is frequently associated with cognitive dysfunction. However, the reasons for this correlation are unclear. Possible influential factors include patient age; duration, frequency, etiology, and type of seizures; hereditary factors; psychosocial issues; and antiepileptic drug (AED) therapy. Whereas many of these factors are beyond the physician's control, AED therapy is one element that can be addressed in treatment decisions by recognizing the potential cognitive effects of particular AEDs. For example, phenobarbital impairs memory and concentration; phenytoin affects attention, problem solving ability, and performance of visuomotor tasks. In contrast, carbamazepine may affect concentration, while valproate would appear to have minimal effects on cognition. Moreover, cognitive effects of AEDs are amplified with coadministration of multiple anticonvulsants (polytherapy). A review of studies on the cognitive effects of monotherapy with AEDs, as opposed to those of polytherapy, provides evidence that drug-related cognitive dysfunction can be reversed if patients are switched to a simpler therapeutic regimen. Future research should be directed toward developing reliable measures for assessing and monitoring cognition, and understanding the particular cognitive side effects of each AED. Physicians also need to revise their opinions about which side effects are "tolerable" for epileptic patients.     

Epilepsy and anomalies of neuronal migration: MRI and clinical aspects

Neuronal migration disorders are the result of disturbed brain development. In such disorders, neurons are abnormally located. In diagnosing these conditions, magnetic resonance imaging is superior to any other imaging technique. This enables us to improve our knowledge of the clinical correlates of neuronal migration. With reference to migrational disorder, a retrospective study of all 303 patients with epileptic seizures referred for magnetic resonance imaging during a 3-year period was performed, 13 patients (aged 12-41, mean age 27) were identified. They represent 4.3% of the entire study group. Of the patients with known epilepsy, 6.7% and of the mentally retarded, 13.7% had migrational disorders. Four patients had schizencephaly as the dominant finding, one was classified as hemimegalencephaly, 2 had isolated heterotopias, and 6 had localized pachy- and/or poly-microgyria. The clinical pictures are complex. Ectopias of grey matter are recognised foci of epilepsy, but from an epileptological and a clinical viewpoint little attention has been given to these disorders. The present study shows that malmigration is not rare in epilepsy patients, especially not in the mentally retarded.     

Carbamazepine Efficacy in Adults With Partial and Generalized Tonic-Clonic Seizures

Summary: Carbamazepine and phenytoin are drugs of choice in initial monotherapy for adult partial and secondarily generalized tonic-clonic seizures. These designations reflect the results of the Veterans Administration Epilepsy Cooperative Study Group of 1985. An earlier comparative study of carbamazepine and phenytoin by Ramsay and associates found both drugs equally effective in controlling new-onset seizures. Among the advantages of carbamazepine is that it causes relatively few cognitive and dysmorphic side effects. Its disadvantages are its unavailability in parenteral formulation and its metabolic autoinduction. The latter must be compensated for by planned dosage increases to maintain therapeutic plasma steady-state levels during the first 2 or 3 months of treatment. Carbamazepine is judged a drug of choice in the treatment of these secondarily generalized tonic-clonic seizures, and the drug of choice in children, adolescents, and women susceptible to the dysmorphic side effects associated with other anticonvulsant agents.     

Etiologic and Preventive Aspects of Epilepsy in the Child–Bridging the Gap Between Laboratory and Clinic

Summary: Four broad categories of basic phenomena are pertinent to developing ways to prevent epilepsy. These include mechanisms of epileptogenesis, ictal initiation and temporary entrainment by the seizure discharge of normally functioning brain, seizure propagation, and control mechanisms that function both to restrain the cascade of epileptic events culminating in a seizure and to arrest the epileptic event and restore the interictal state. In newborns and children, hypoxia-ischemia is a major factor leading to epileptogenesis, and several schemes are proposed to classify, quantify, and prevent hypoxic-ischemic encephalopathy. Control mechanisms must be better understood in order to develop prophylactic recommendations for epilepsy, and an experimental model of "kindling antagonism" may increase our understanding of these. Programs of prevention of seizures in children will evolve only if basic researchers and clinicians work productively together to develop an adequate understanding of factors important in epileptogenesis and antiepileptogenic control mechanisms.     

Predisposing and Causative Factors in Childhood Epilepsy

Summary: We review information from large studies of defined populations, examining the role of known factors and especially of prenatal and perinatal factors in contributing to nonfebrile seizure disorders of early childhood. We depend especially, but not exclusively, on the recently completed analyses from the Collaborative Perinatal Project of the National Institute of Neurological and Communicative Disorders and Stroke, the NCPP. About 4% of children in the NCPP who had at least one non-febrile nonsymptomatic seizure by the age of 7 years had a previous seizure during acute neurologic illness, such as meningitis or during the acute illness after trauma. Many such seizures should potentially be preventable. Of children with seizures, 10% had had a neonatal seizure and 13% had had a febrile seizure. Among the hundreds of prenatal and perinatal factors explored as predictors of childhood seizure disorders, the principal predictors identified were congenital malformations of the fetus, cerebral and noncerebral; family history of certain neurologic disorders; and neonatal seizures. In agreement with the British National Child Development Study, labor and delivery factors in the NCPP appeared to contribute very little to childhood seizure disorders. Maldevelopment, rather than damage at birth to an initially intact nervous system, appeared to be the more common mechanism. Most seizure disorders of early childhood remained unexplained by the large set of prenatal and perinatal characteristics examined.     

Classification of methods in transcranial Electrical Stimulation (tES) and evolving strategy from historical approaches to contemporary innovations

Transcranial Electrical Stimulation (tES) encompasses all methods of non-invasive current application to the brain used in research and clinical practice. We present the first comprehensive and technical review, explaining the evolution of tES in both terminology and dosage over the past 100 years of research to present day. Current transcranial Pulsed Current Stimulation (tPCS) approaches such as Cranial Electrotherapy Stimulation (CES) descended from Electrosleep (ES) through Cranial Electro-stimulation Therapy (CET), Transcerebral Electrotherapy (TCET), and NeuroElectric Therapy (NET) while others like Transcutaneous Cranial Electrical Stimulation (TCES) descended from Electroanesthesia (EA) through Limoge, and Interferential Stimulation. Prior to a contemporary resurgence in interest, variations of transcranial Direct Current Stimulation were explored intermittently, including Polarizing current, Galvanic Vestibular Stimulation (GVS), and Transcranial Micropolarization. The development of these approaches alongside Electroconvulsive Therapy (ECT) and pharmacological developments are considered. Both the roots and unique features of contemporary approaches such as transcranial Alternating Current Stimulation (tACS) and transcranial Random Noise Stimulation (tRNS) are discussed. Trends and incremental developments in electrode montage and waveform spanning decades are presented leading to the present day. Commercial devices, seminal conferences, and regulatory decisions are noted. We conclude with six rules on how increasing medical and technological sophistication may now be leveraged for broader success and adoption of tES.     

Treatment Considerations in Anticonvulsant Monotherapy

Summary: The long-standing practice of polypharmacy in treating epilepsy is giving way to use of monotherapy. Monotherapy can improve seizure control as well as reduce the risk of serious idiosyncratic reactions, dose-related side effects, and complex drug interactions. Monotherapy also offers improved compliance and cost-effectiveness. The basis of monotherapy is accurate diagnosis and assessment of the patient's seizure type(s), followed by selection of a single appropriate anticonvulsant drug. Many patients currently treated with multiple anticonvulsants can be successfully converted to monotherapy with a carefully monitored program in which troublesome and redundant drugs are gradually withdrawn from the therapeutic regimen.     

Anticonvulsant Drugs and Cognitive Function: A Review of the Literature

Summary: Alterations of cognitive function are separate from disturbances of behavior seen in association with epilepsy. The nature of the cognitive disability may to a certain extent depend on the seizure type. Partial seizures, mainly derived from a temporal lobe focus, impair memory tasks, while generalized seizures seem to have more effect on attentional abilities. A number of studies, reviewed in this paper, suggest that anticonvulsant drugs further impair cognitive function. Maximal impairments are seen in patients receiving polytherapy: rationalization of polytherapy improves cognitive abilities. Studies in children and adults have allowed differentiation of the effects of various commonly used antiepileptic agents. Maximal cognitive deficits are seen with. phenytoin, while phenobarbital and sodium valproate induce moderate disturbances, and carbamazepine seems relatively free from such toxicity. Further research is needed on the interrelationship between types of seizure disorders, types of anticonvulsant medications, and cognitive function.     

Dextromethorphan: Cellular Effects Reducing Neuronal Hyperactivity

Summary: Dextromethorphan is a dextrorotary morphinan without affinity for opioid receptors, commonly used as an antitussive medication. During the past 5 years, interest in the compound and its demethylated derivative, dextrorphan, has been revived because additional neuroprotective and an-tiepileptic properties were found in in vitro studies, animal experiments, and a few clinical cases. Both morphinans are able to inhibit N -methyl-D-aspartate (NMDA) receptor channels and voltage-operated calcium and sodium channels with different potencies. The inhibition of the NMDA receptor is believed to be the predominant mechanism of action responsible for the anticonvulsant and neuroprotective properties of the compounds.