乙状窦前和乙状窦后入路微创显露膝状神经节的虚拟现实比较

目的：通过虚拟现实技术比较乙状窦前和乙状窦后入路微创显露膝状神经节的显微解剖特征。方法对15例尸体头颅行M RI和C T扫描,将影像数据输入虚拟现实系统,构建颞骨三维解剖模型,在颅盖和颅底选择骨性标志点勾勒乙状窦前和乙状窦后入路显露膝状神经节的手术路径。观察两种路径的解剖结构空间形态和顺序,测量解剖组织体积,采用配对 t检验进行比较分析。结果乙状窦前入路由乳突开始磨除岩骨,避开乙状窦和颈静脉球,经过面神经垂直段、听骨链、迷路,到达膝状神经节时,显露面神经。乙状窦后入路由横窦下方开颅,经过小脑半球,到达内听道时磨除岩骨,经过面听神经复合体,到达膝状神经节,路径中包含听骨链和迷路。手术路径和迷路体积测量：乙状窦后入路＞乙状窦前入路;面听神经复合体和听骨链体积：乙状窦前入路＞乙状窦后入路,差异均有统计学意义（P ＜0．05）。乙状窦后入路中小脑半球体积为（462．72±20．87）mm3,乙状窦前入路不包含小脑半球。两种路径中骨性结构（不包含听骨链）体积的差异无统计学意义（P＞0．05）。结论在磨除岩骨显露膝状神经节的路径中,乙状窦前入路有助于减少迷路损伤范围,乙状窦后入路有助于减少听骨链损伤范围并显露面听神经复合体。     

经远外侧入路和乙状窦前入路显露下斜坡的虚拟现实显微解剖学研究

目的利用虚拟现实技术比较经远外侧入路和经乙状窦前入路显露下斜坡的三维解剖结构显露情况。方法在虚拟现实系统中输入15例(30侧)尸头的CT和MRI影像数据构建颅后窝三维解剖模型。选择双侧颈静脉结节前缘和咽结节三点为标记点确定平面,平面以下斜坡区域为下斜坡,平面与斜坡相交曲线前缘为颅底显露标记点。枕髁关节面后缘和乳突尖部分别为经远外侧入路和经乙状窦前入路的开颅标记点,采用直径1 cm圆柱模拟手术路径,圆柱轴线经过开颅标记点。圆柱颅底侧底面圆上缘位于上述颅底显露标记点。采用配对t检验比较两种手术路径中解剖结构显露情况。结果经远外侧入路位于枕骨大孔外侧缘,经过小脑半球腹侧、脑干外侧、颈静脉球内侧、副神经外侧和下部,到达下斜坡,包含舌下神经;经乙状窦前入路由乳突尖部开始磨除岩骨,经过颈静脉球下缘,通过乙状窦前部,位于副神经下部,于枕骨大孔外侧缘经过舌下神经,到达脑干前部下斜坡。在以下斜坡为显露终点的两种手术路径的比较中,经乙状窦前入路手术路径[(4629.80±81.00)mm~3对(2622.60±72.58)mm~3;t=91.532,P=0.000]和路径中包含舌下神经[(10.15±0.17)mm~3对(7.15±0.20)mm~3;t=52.413,P=0.000]的体积大于经远外侧入路,经远外侧入路去除骨性结构的体积大于经乙状窦前入路[(2362.90±80.18)mm~3对(1851.60±63.62)mm~3;t=25.714,P=0.000]。结论经远外侧入路和乙状窦前入路经过舌下神经时,通过去除部分颅底骨性结构有助于避开小脑和脑干显露下斜坡。     

乙状窦后和乙状窦前入路微创显露颈静脉结节的虚拟现实对比研究

目的在构建虚拟现实解剖模型基础上,量化比较乙状窦后和乙状窦前入路微创显露颈静脉结节的显微解剖特征。方法 15例(30侧)尸头行CT和MRI扫描,影像数据输入虚拟现实系统构建颅后窝三维解剖模型。在颅盖和颅底中选择骨性标志点模拟乙状窦后和乙状窦前入路微创路径,观察和测量两种手术路径中解剖结构显露情况,采用配对t检验进行比较分析。结果乙状窦后入路由横窦下方开颅,包含小脑半球和小脑前下动脉,到达颈静脉结节时,路径包含舌咽、迷走、副神经和岩下窦。乙状窦前入路由乳突磨除岩骨,经过颈静脉球下端和颈内静脉,到达颈静脉结节时,包含部分副神经。测量手术路径和后组脑神经体积:乙状窦后入路乙状窦前入路;路径中骨性结构和静脉体积:乙状窦前入路乙状窦后入路,差异均有统计学意义(P0.05)。乙状窦后入路中包含小脑半球体积为(2750.50±123.27)mm3、小脑前下动脉体积为(78.72±1.75)mm3,乙状窦前入路不包含上述结构。结论乙状窦后入路有利于显露后组脑神经,显露过程应注意保护小脑和小脑前下动脉。乙状窦前入路显露颈静脉结节时,受到磨除岩骨操作和保护静脉窦的限制,适于处理累及颈静脉孔的病变。     

经颞下乙状窦前入路切除岩斜区肿瘤12例

岩斜区肿瘤基底位于内听道以内岩尖斜坡区域。其位置深在,周期重要结构毗邻,手术入路受到岩锥阻挡,肿瘤残留率及致残率均较高。传统的乙状窦后入路(枕下入路)和颞下人路在处理肿瘤时因岩锥阻挡及手术径路过深造成显露、操作困难。乙状窦前(迷路后、经迷路)入路已渐成为传统入路的重要替代和选择之一。我科于2000年2月至2002年3月,经乙状窦前入路切除岩斜区肿瘤12例,现将手术情况及结果报告如下。     

经中颅窝小脑幕迷路联合途径治疗大型听神经瘤患者的面神经保留

作者报告大型听神经瘤经中颅窝小脑幕一迷路联合侧方入路手术方法,该入路能较满意地达到全切肿瘤和保留面神经功能的目的.方法:患者仰卧,头向健侧旋转90°使颞鳞呈水平位.头皮切口自乳突开始,向上环绕外耳,到颧弓为止.而后经迷路解剖,切除内听道的上、下、后壁,上内侧切除岩骨尖端,向下显露至颈静脉球,上方把顶盖修薄,后方将后颅窝硬膜上方的骨质完全切除,显露乙状窦.作一颞部小骨瓣.将复盖在迷路上方残留的中颅窝底骨质完全去除,前内侧到岩上窦为止.垂直切开颞叶表面的硬膜,注意避开来自颞叶侧、下方的静脉,硬膜切口向下越过中颅窝底直至岩上窦.垂直切开后颅窝硬膜,下抵颈静脉球,上达岩上窦,在两把止血钳间切断岩上窦.切开小脑幕至切迹,该处可见中脑和第四颅神经,且多能从环池流出多量     

乙状窦后经内耳道上入路显露范围的量化研究

目的量化研究在乙状窦后入路基础上磨除内耳道上区骨性结构前后显露颅中窝、上斜坡的变化情况。方法在8～12倍手术显微镜下对成人颅骨标本10例、10%甲醛溶液固定头颅标本18例进行研究。经乙状窦后入路开颅,磨除内耳道上结节和部分岩尖,采用实体和CT相结合的方法测量内耳道上结节、岩尖的切除范围,记录内耳道上结节、岩尖切除前后颅中窝、上斜坡的显露面积和三叉神经的显露范围。结果内耳道上结节左右方向、前后方向骨性组织可全部切除,将内听道的上壁轮廓化切除其上下径;岩尖的前后、左右方向、上下方向骨性组织均不能完全切除。颅中窝扩大显露范围为(144.6±13.9)mm2,上斜坡扩大显露(90.3±16.7)mm2。结论采用乙状窦后经内耳道上入路,可将乙状窦后入路的手术野扩大到颅中窝的中线侧和上斜坡侧方,并可显露Meckel腔内的三叉神经。     

乙状窦前入路处理斜坡凹陷区病变的量化研究

目的量化研究乙状窦前入路中每一步岩骨切除及血管神经牵拉完成后获得的斜坡中央凹陷区显露范围及手术自由度。方法对20例头颅标本采用乙状窦前入路,骨切除分4步进行：迷路后骨质切除,上、后半规管切除,切除岩尖并打开Meckel＇s腔游离三叉神经,全切迷路及耳蜗并后移面神经。每一步完成后分别测量斜坡中央凹陷区的显露范围和手术自由度。结果岩尖切除、打开Meckel＇s腔游离三叉神经后,斜坡中央凹陷区显露面积为（190±32）mm^2,占整个入路完成后的95％,与磨除上、后半规管后的显露范围相比差异显著,手术自由度亦显著增加。结论乙状窦前联合部分迷路岩尖切除手术入路能够较好的显露斜坡中央凹陷区。岩尖的切除和打开Meckel＇s腔游离三叉神经是充分显露斜坡中央凹陷区并提供足够手术自由度的关键步骤。     

虚拟现实系统对乙状窦前入路微创显露颈静脉孔区的解剖学研究

目的虚拟现实系统模拟经岩骨乙状窦前入路显露颈静脉孔区的手术路径并探讨微创化策略。方法 15具(30侧)尸头标本行CT和MRI扫描,影像学数据输入虚拟现实系统以构建颈静脉孔区三维解剖模型,选择骨性标记点绘制圆柱模拟经岩骨乙状窦前入路手术路径,将圆柱直径缩小模拟手术路径微创化,观察并测量微创化前后手术路径中所包含的解剖结构。结果虚拟现实系统模拟经岩骨乙状窦前入路显露颈静脉孔区的手术路径可清晰显示所包含的神经、血管等解剖结构的空间层叠顺序,微创化前后手术路径均由岩骨内面神经垂直段与乙状窦之间经过,包含部分乙状窦,不包含小脑半球。微创化后手术路径体积,以及路径中岩骨骨性结构和静脉窦体积均小于微创化前(P=0.000);微创化前后后组脑神经体积差异无统计学意义(P=0.552)。结论经岩骨乙状窦前入路手术路径微创化可在有效显露颈静脉孔区靶结构的情况下减少重要解剖结构的损伤。     

神经内镜辅助下乙状窦前迷路后锁孔入路处理岩斜区病变的应用解剖研究

目的 为神经内镜辅助下乙状窦前迷路后锁孔手术入路处理岩斜区病变提供解剖学基础.方法 取10例(20侧)经福尔马林固定成人头颅标本,采用耳后"C"形切口,切口长度约6cm,模拟乙状窦前迷路后入路,神经内镜及显微镜下观察所显露的解剖结构.结果 乙状窦前缘与后半规管平面的水平距离为:右侧(9.1±1.3)mm,左侧(9.6±1.8)mm.通过调整神经内镜及显微镜角度,经乙状窦前迷路后锁孔入路可显露岩斜区的一些重要结构,清晰显示脑神经及其附近走行的血管.结论 面、前庭蜗神经及内耳道后唇均可以作为神经内镜下经乙状窦前迷路后入路定位岩斜区及其周围结构的标识.     

虚拟现实技术量化比较Kawase和乙状窦前入路显露上斜坡的显微解剖

目的在虚拟现实影像模型中评估Kawase入路和乙状窦前入路显露上斜坡的解剖差别。方法对15例尸头进行CT和MRI扫描,影像数据输入虚拟现实系统构建颅后窝三维解剖模型。在颅盖和颅底骨性结构中选取标志点勾勒Kawase入路和乙状窦前入路显露上斜坡的手术路径。测量解剖结构体积,比较两种手术路径的显露特征。结果两种入路通过磨除岩骨到达上斜坡,乙状窦前入路手术路径、路径中包含骨性结构和静脉结构的体积均多于Kawase入路,Kawase入路中包含脑神经体积多于乙状窦前入路,差异均有统计学意义(P0.05)。结论比较Kawase入路和乙状窦前入路显露上斜坡的解剖特征有助于指导选择合适的手术入路。     

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.     

Hepatic Considerations in the Use of Antiepileptic Drugs

Summary: Virtually all of the major antiepileptic drugs (AEDs) can cause hepatotoxicity, although fatal hepatic reactions are rare. The mechanisms, incidences, and risk profiles for such reactions differ from drug to drug. With carbamazepine and phenytoin, hepatotoxicity may be due to drug hypersensitivity. Although the profiles of patients at risk have not been well-defined for these two antiepileptic drugs, it would appear from reports in the literature that older adolescents and adults are at higher risk than children of developing serious or fatal hepatotoxicity. Once hepatotoxicity develops, mortality rates are 10–38% with phenytoin and 25% for carbamazepine. The risk profile for valproate fatal hepatotoxicity has been more clearly defined. Those at primary risk of fatal hepatic dysfunction are children under the age of 2 years who are receiving multiple anticonvulsants and also have significant medical problems in addition to severe epilepsy. The risk is considerably lower for patients over the age of 2 years on valproate monotherapy. In contrast to the risk profile with other AEDs, adults receiving valproate as monotherapy have the lowest risk of hepatotoxicity. Fatal hepatic dysfunction coincident with valproate may be the result of aberrant drug metabolism. Concomitant use of AEDs that induce microsomal P450 enzymes (e.g., phenytoin and phenobarbital) may enhance the production of a toxic metabolite, and hence the greater risk of hepatotoxicity with polypharmacy.     

Vascular Malformations and Epilepsy: Clinical Considerations and Basic Mechanisms

Summary: Vascular malformations (VMs) are associated with epilepsy. The natural history of the various VMs, clinical presentation, and tendency to provoke epilepsy determine treatment strategies. Investigations have probed the mechanisms of epileptogenesis associated with these lesions. Electrophysiologic changes are associated with epileptogenic cortex adjacent to VMs. Putative pathophysiologic mechanisms of epileptogenesis include neuronal cell loss, glial proliferation and abnormal glial physiology, altered neurotransmitter levels, free radical formation, and aberrant second messenger physiology.     

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.     

Carbamazepine Efficacy and Utilization in Children

Summary: Carbamazepine is effective for preventing partial and generalized tonic-clonic seizures in children. Although absence epilepsies are more common in children than adults, an estimated 80% of children with epilepsy have seizure types or epilepsies that are potentially responsive to carbamazepine. The differential diagnosis of ictal staring is an especially important issue in children because absence and atypical absence seizures are more prevalent in children than adults. Age-related pharmacokinetic differences and drug interactions are major considerations in children. On average, children have higher clearance rates of carbamazepine, shorter half-lives, and higher ratios of carbamazepine-10, 11-epoxide to carbamazepine than adults. In addition, children with severe epilepsy are more likely to require multiple-drug therapy, which can lead to complex drug interactions. When carbamazepine is administered along with valproate, drug protein binding interactions can cause intermittent side effects.     

Neonatal Seizures: Problems in Diagnosis and Classification

Summary: The clinical identification of neonatal seizures is critical for the recognition of brain dysfunction; however, diagnosis is often difficult because of the poorly organized and varied nature of these behaviors. Current classification systems are limited in their ability to communicate motor, autonomic, and electroencephalo-graphic features of seizures precisely and to provide a basis for uniform effective diagnosis, therapy, and determination of prognosis. Recent investigations of neonates, utilizing bedside electroencephalographic/polygraphic/ video monitoring techniques, have provided the basis for improved diagnosis and classification of seizures in the newborn. These studies have demonstrated that not all clinical phenomena currently considered to be seizures require electrocortical epileptiform activity for their initiation or elaboration. In addition, the specific clinical character of the phenomena considered to be seizures, the clinical state of the infant, and the character of the EEG indicate the probable pathophysiological mechanisms involved and suggest probable etiologies, prognosis, and therapy. Similarities between animal models that demonstrate reflex physiology and neonates with motor automatisms and tonic posturing suggest that these clinical behaviors may not be epileptic in origin but, rather, primitive movements of progression and posture mediated by brainstem mechanisms. Although not all clinical behaviors currently considered to be neonatal seizures may have similar pathophysiological mechanisms, they are clinically significant because they all indicate brain dysfunction.     

Valproate Monotherapy in the Management of Generalized and Partial Seizures

Summary: For decades, therapeutic tradition has promoted the concept of polypharmacy in the management of epilepsy. In recent years, however, studies have shown that, for most patients, monotherapy can provide comparable or better seizure control than administration of multiple anticonvulsants, while diminishing the potential for adverse reactions, drug interactions, and poor compliance. Valproate is an important monotherapeutic agent that is highly effective in the control of idiopathic primary and secondarily generalized epilepsies, and partial seizures that do not generalize. Comparative studies have found that valproate is at least as effective as phenytoin and carbamazepine in the treatment of generalized and partial seizures. Given the similar efficacy, other factors such as pharmacokinetics and side effects may therefore determine anticonvulsant selection for monotherapy.     

Un nouveau cadre conceptuel de travail pour la psychiatrie

In an attempt to place psychiatric thinking and the training of future psychiatrists more centrally into the context of modern biology, the author outlines the beginnings of a new intellectual framework for psychiatry that derives from current biological thinking about the relationship of mind to brain. The purpose of this framework is twofold. First, it is designed to emphasize that the professional requirements for future psychiatrists will demand a greater knowledge of the structure and functioning of the brain than is currently available in most training programs. Second, it is designed to illustrate that the unique domain which psychiatry occupies within academic medicine, the analysis of the interaction between social and biological determinants of behavior, can best be studied by also having a full understanding of the biological components of behavior.     

Special Pharmacokinetic Considerations in Children

Summary: Pediatric patients have greater degrees of pharmacokinetic variability and unpredictability than adults. This variability results from the effects of pharmacogenetics, age and growth, prior and current comedication, and disease. Newborns with seizures have the least predictable dosage requirements, and their needs change as drug-eliminating mechanisms mature in the neonatal period. Infants have the highest relative capacities to eliminate antiepileptics of any age group and require the largest relative doses. In addition to age-related trends, children demonstrate the same drug-specific, pharmacokinetic phenomena that adults do, including nonlinear phenytoin elimination, nonlinear valproate binding, and autoinduction of carbamazepine. Intercurrent illness and drug interactions further modify the age-related pharmacokinetic patterns in children and make dosage requirements even more unpredictable. Recent studies have shown that febrile illness can affect drug elimination, sometimes decreasing drug levels by 50% or more. Intermittent treatment with benzodiazepines administered either orally or rectally can be an important adjunct and help minimize this type of problem for children with marginally controlled epilepsy. Intermittent benzodiazepines are also helpful for children who have febrile seizures and who need only occasional antiepileptic protection.