椎动脉发育不良与后循环缺血性卒中： 从假说到发病机制

椎动脉发育不良是临床常见的后循环血管变异。已有的研究结果显示,椎动脉发育不良是
后循环缺血性卒中的危险因素,并与之存在区域性关联。椎动脉发育不良在后循环缺血性卒中的发
生发展中起到重要作用。本文对椎动脉发育不良与后循环缺血性卒中之间的关系以及潜在的发病机
制进行综述,以期为后循环缺血性卒中的科学预防和临床治疗提供参考。     

椎动脉发育不良的临床现状研究

椎动脉发育不良与椎动脉先天闭塞,特别是在椎动脉的解剖变异中,是一种并不常见的 后循环胚胎变异。大量数据表明在伴或不伴有基底动脉形态变异的情况下,尤其在合并了其他脑血管 危险因素时,后循环缺血的发生与椎动脉发育不良有关。尽管在椎动脉发育不良的定义与评估方法上 仍存在争议,既往的研究通过彩色多普勒超声发现同侧的发育不良的椎动脉净流速降低,而发育正 常的椎动脉净流速代偿性的增加,导致局部血流低灌注,甚至出现临床症状,说明椎动脉发育不良 具有更易于闭塞的特点,并增加了远端血栓形成的概率[1]。此外,椎动脉发育不良可能引发其他复杂 的神经血管疾病如偏头痛、前庭神经元炎、发作性眩晕以及椎动脉夹层等。     

椎动脉发育不全与卒中

目的 先天的椎动脉发育不全是一种后循环罕见的胚胎变异。从尸体解剖和血管造影中发现这种先天变异的频率为2%～6%。此研究的目的是阐明椎动脉发育不全在急性脑梗死中的作用。方法 我们收集了195位急性脑梗死患者(年龄57±13岁),并对每位受试者进行脑梗死类型（TOAST分型）的分类及磁共振血管造影（Magnetic Resonance Angiography,MRA）,并于卒中后72h内完成颈动脉超声及椎动脉血流量测量。结果 单侧的先天椎动脉发育不全总的发生率是11.79%;脑干、小脑梗死患者中发生率特别高。先天椎动脉发育不全与TOAST分类“大动脉粥样硬化”子类型相关。结论 基于我们的结果,先天椎动脉发育不全,特别在后循环上的先天椎动脉发育不全似乎是一种脑梗死的加重因素。     

椎动脉优势与后循环梗死的关系

目的 探讨椎动脉优势(vertebral artery dominance)与后循环梗死发生率及梗死侧的关系.同时了解椎动脉优势与基底动脉弯曲的相关性.方法 134例缺血性脑血管疾病、脑出血及突发性耳聋患者根据其是否存在椎动脉优势分为有椎动脉优势68例(优势组)和无椎动脉优势66例(对照组).比较两组间后循环梗死总发生率,后循环各部位的梗死发生率以及基底动脉弯曲的发生率.统计优势组各梗死部位后循环梗死侧与椎动脉优势侧的相关性,基底动脉弯曲方向与椎动脉优势侧的相关性,基底动脉弯曲与否与后循环梗死的相关性.结果 优势组后循环梗死发生率高于对照组[45.6％ (31/68)与21.2％(14/66),x2=8.922,P=0.003].优势组小脑后下动脉(PICA)供血区梗死及基底动脉供血区梗死发生率显著高于对照组[11.8％ (8/68)与0,x2=8.250,P=0.004;20.6％(14/68)与7.6％ (5/66),x2=4.660,P =0.031];两组的小脑上动脉供血区梗死率及大脑后动脉供血区梗死率差异无统计学意义.7例(7/8) PICA梗死患者梗死侧在椎动脉优势对侧.6例(6/14)基底动脉区梗死患者梗死侧与优势侧同侧.优势组基底动脉弯曲发生率显著高于对照组[50.0％(34/68)与9.1％ (6/66),x2=26.768,P=0.000].优势组基底动脉弯曲患者后循环梗死发生率与基底动脉呈直线的患者相仿,差异无统计学意义[ 52.9％ (18/34)与38.2％ (13/34),x2=1.482,P=0.223].优势组34例基底动脉弯曲的患者中,97.1％ (33/34)弯曲向椎动脉优势对侧.结论 椎动脉优势的患者较易发生后循环梗死,尤其是PICA和基底动脉供血区梗死,PICA供血区梗死部位一般在椎动脉优势对侧.椎动脉优势患者易致基底动脉弯曲,基底动脉一般弯向椎动脉优势对侧.     

椎动脉优势与后循环缺血性眩晕的关系

目的 探讨椎动脉优势在后循环缺血性眩晕(VAIV)中的临床意义.方法 前瞻性收集经头颅MRA检查发现的椎动脉优势的VAIV患者41例为研究对象,以非椎动脉优势的患者36例为对照,比较两组患者的基底动脉情况及眩晕严重程度.将椎动脉优势组患者根据椎动脉直径差异分为轻度变异组(0.04～0.70mm)、中度变异组(0.70～1.17 mm)、重度变异组(≥1.17 mm)3组,比较3组患者的眩晕严重程度差异.所有患者均随访1年,观察椎动脉优势与阳性事件发生(眩晕反复发作或发生后循环脑梗死)的关系.结果 (1)椎动脉优势组基底动脉形状异常率为70.73％(29/41),明显高于非椎动脉优势组33.33％(12/36)(x2=10.77,P＜0.01);(2)椎动脉优势组眩晕严重程度(3.3±1.2)高于非椎动脉优势组(2.3±0.6)(t=1.99,P＜0.01);不同变异3组间两两比较,椎动脉优势重度变异组眩晕严重程度(4.0±1.1)大于轻度变异组(2.9±0.9)(t=2.07,P＜0.05);(3)随访1年后,椎动脉优势组阳性事件发生率(65.85％)高于非优势组(30.56％)(x2=9.56,P＜0.01).结论 椎动脉优势的VAIV患者基底动脉异常率高,眩晕程度更严重,更容易反复发作眩晕或发生后循环脑梗死.     

椎动脉发育不良的MRA诊断分析

目的探讨MRA诊断椎动脉发育不良,研究椎动脉发育不良与后循环缺血的关系。方法 312例缺血性脑血管病患者同时行头/颈部MRA及头颅磁共振平扫检查,根据是否存在椎动脉发育不良,分为椎动脉发育不良72例(观察组),非椎动脉发育不良240例(对照组),比较2组间后循环TIA及后循环梗死的总发生率,分析椎动脉发育不良与后循环TIA和后循环梗死的相关性。结果 312例患者中,椎动脉发育不良72例,其中右侧58例,左侧14例;后循环TIA 50例,发生率69.44%,后循环梗死22例,发生率30.56%;其余240例患者,前循环症状表现192例,后循环症状表现48例,发生率20%,其中后循环TIA 30例,发生率12.5%;后循环梗死18例,发生率7.5%;2组比较,P=0.000,差异有统计学意义。结论 MRA是椎动脉发育不良较为理想的检查手段,椎动脉发育不良与后循环TIA和后循环脑梗死有明显的相关性,是缺血性卒中的危险因素。     

主动脉弓分支血管变异的研究进展

主动脉弓分支血管发生变异是常见的现象，常见的变异类型有：牛型弓、椎动脉起自主动脉弓、右锁骨下动脉迷行，其他类型的变异较为罕见。主动脉弓上血管的变异来源于胚胎时期原始咽弓动脉的发育异常，但影响变异产生的具体机制尚不明确。虽然主动脉弓分支血管变异通常为无症状的，但其部分与先天性心血管疾病及遗传性疾病的发生存在明显相关性。由于变异的发生，外科手术或血管内治疗操作的难度和危险性会明显增高。本文基于国内外关于主动脉弓分支血管变异研究的现状，针对变异的类型、胚胎学发生机制及其对临床工作产生的影响等方面进行综述。     

后循环缺血患者脑主要供血动脉病变及危险因素分析

目的探讨后循环缺血(PCI)患者椎-基底动脉病变情况及危险因素。方法对2007-2009年诊断为PCI并行DSA检查的75例患者的临床和DSA资料进行回顾性分析。结果 78.67%患者有后循环动脉病变,其中单纯后循环闭塞、狭窄占38.98%;后循环闭塞、狭窄伴其他病变(包括扭曲、发育不全、夹层、变异)占32.20%;单纯其他病变占28.82%。后循环闭塞、中重度狭窄常见部位依次为椎动脉V1段(52.73%),椎动脉V4段(27.27%),基底动脉(7.27%)。具有后循环闭塞、狭窄组,高血压病、高脂血症的发生率高于无动脉病变组(X2=5.665,P=0.017;X2=5.525,P=0.019)。结论 PCI患者DSA检查阳性率较高,包括后循环闭塞、狭窄、扭曲、发育不全、夹层及变异。后循环闭塞、中重度狭窄最常见部位为椎动脉V1段。应重视PCI患者高血压病、高脂血症等危险因素的识别和干预。     

不同类型椎动脉V3段颅底凹陷合并寰枢椎脱位的内固定策略

目的研究颅底凹陷合并寰枢椎脱位患者椎动脉V3段的危险变异类型和发生率, 探讨不同类型椎动脉V3段患者的内固定策略。方法回顾性分析2017年1月至2019年1月首都医科大学宣武医院神经外科采用内固定融合手术重建颅颈交界区稳定性的56例颅底凹陷合并寰枢椎脱位患者的临床和影像学资料。对于不合并椎动脉解剖变异的患者, 采取寰椎侧块螺钉联合枢椎椎弓根螺钉行内固定治疗;对于椎动脉骨外段变异患者, 术中尽可能采取枕骨螺钉替代寰椎侧块螺钉;对于高跨椎动脉(骨内段变异)患者, 采用枢椎椎板螺钉或者峡部螺钉代替椎弓根螺钉。所有患者术后均常规行颈椎X线平片和头颈部CT检查评估内固定器械的位置以及是否发生后循环缺血梗死。结果 56例患者中, 不合并椎动脉变异患者18例(32.1%);椎动脉骨外段变异20例(35.7%), 包括永存第一节间椎动脉16例, 椎动脉开窗和硬膜外起源小脑后下动脉各2例;高跨椎动脉28例(50.0%)。其中, 骨外段变异合并高跨椎动脉变异10例(17.9%)。56例患者在置入枢椎螺钉时均未出现椎动脉损伤情况。1例椎动脉开窗患者术中显露寰椎侧块和寰枢椎关节时, 开窗椎动脉下干损伤大出血,...     

椎动脉狭窄与后循环缺血的相关性研究

目的：分析椎动脉狭窄与后循环缺血（PCI）的相关性。方法选取因急性后PCI症状就诊的椎动脉狭窄或闭塞患者110例为研究对象,对患者椎动脉狭窄或闭塞的部位、程度和不同程度椎动脉狭窄或闭塞所致的脑梗死灶体积进行检测和比较。结果110例患者中,共检出椎动脉狭窄218处,椎动脉闭塞45处,两侧椎动脉在狭窄或闭塞的部位及狭窄程度方面差异均无统计学意义（P＞0.05）;双支椎动脉狭窄、闭塞所致的脑梗死灶体积显著高于单支椎动脉重度狭窄或单支椎动脉闭塞（P＜0.05）,单支椎动脉重度狭窄或单支椎动脉闭塞所致的脑梗死灶体积显著高于单支椎动脉轻度狭窄或单支椎动脉中度狭窄（P＜0.05）。结论 PCI患者椎动脉狭窄程度与脑梗死病灶体积具有相关性,可作为反映PCI患者脑梗死病情的参考依据。     

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.     

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.     

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.     

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.     

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.     

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.