[Vertebrobasilar ischemia of thrombotic and embolic origin]

OBJECTIVE

To analyze the mechanisms involved in the appearance of ischemia in vertebro-basilar territory, especially those of embolic or thrombotic characteristics.

DEVELOPMENT

The mechanism of vertebro-basilar ischemia had not been adequately studied until a few years ago. This had led to the belief that most were due to a haemodynamic mechanism. However, in recent years studies of large numbers of patients, in whom cardiological and neurovascular evaluation had been systematically carried out, has shown that this is not so. In general, the commonest mechanism is embolism, both of arterial and of cardiac origin. Local thrombosis and a haemodynamic mechanism are less common. The arterial lesions most often associated with intra-arterial embolism have their origins in the intracranial segment of the vertebral artery. The most frequent sites of blockage by emboli are the distal segments of the basilar artery, the superior cerebellar artery, the posterior cerebral artery and the intracranial region of the vertebral artery-posteriorinferior cerebellar artery.

CONCLUSIONS

The mechanism of vertebro-basilar ischemia is not homogeneous and can not be taken for granted in any patient in particular. For this reason it is necessary to carry out a full clinical study of patients with these symptoms, similar to that done for patients with carotid ischemia. This permits not only individualized, correct treatment of each patient but also a more complete knowledge of the mechanisms of ischemia in this territory.

Stroke due to a fusiform aneurysm of the cervical vertebral artery: case report

Aneurysms of the cervical vertebral artery (VA) are uncommon; they are often caused by trauma or spontaneous dissection. A fusiform aneurysm without evidence of atherosclerosis or dissection has not been reported previously. A 46-year-old man presented with a pontine infarct. Imaging revealed a fusiform aneurysm of the left VA at the C5-6 level, with occlusion of the basilar artery. Associated minor anomalies included fusion of the vertebral bodies of C5 and C6, cervical rib and platybasia. The left VA arose directly from the aortic arch and entered the transverse foramen at the C4 level. Hyperextension and left lateral flexion of the neck caused kinking of the VA proximal to the aneurysm. Turbulent flow in the aneurysm lumen was noted on angiography.

[Vascular risk factors in patients with infratentorial vertebrobasilar ischemia]

INTRODUCTION

Arteriosclerosis is the commonest aetiology of vertebro-basilar ischemia (VBI). In the literature few studies mention the risk profile of cerebrovascular accidents at this site.

MATERIAL AND METHODS

In order to establish whether this profile has specific characteristics, we carried out a transversal study of 70 patients with VBI of artherothrombotic origin situated in the brain stem or cerebellum, determining the prevalence of the main risk factors (RF). The results were compared with a control group of individuals who had no cerebral vascular pathology and also with another group who had arteriosclerotic obstructive lesions of the carotid artery as an example of involvement of another vascular territory.

RESULTS

In the the group of patients with VBI we found greater prevalence of hypertension, smoking, ischaemic cardiopathy, peripheral vascular disease and excessive alcohol consumption together with raised levels of arterial hypertension, haematocrit, haemoglobin and total cholesterol as compared with the control group and within a similar range to the group of patients with ischemia of the carotid territory. We underline the high prevalence of diabetes in patients with VBI (45.7%), considerably greater than that of the control group (12.5%), than those with carotid pathology (20.4%) and that described in the literature (17-25%).

CONCLUSIONS

According to our results, the prevalence of RF in VBI and in carotid pathology is similar, except in the case of diabetes. This may play a more decisive role in territory such as the vertebro-basilar, where vascularization is basically by small calibre vessels.

Arterial changes after thrombolysis and percutaneous transluminal angioplasty in vertebrobasilar thrombosis

We present clinicopathologic findings in a patient treated with intraarterial thrombolysis and angioplasty for vertebrobasilar thrombosis. Autopsy revealed a marked inflammatory infiltrate within the vertebral artery at the site of catheter manipulation. This finding may have important implications for the use of interventional angiography in cerebrovascular disease.

[Trigeminal neuralgia caused by tortuous vertebrobasilar system--the clinical and imaging features]

Ten (6.8%) out of 146 patients with trigeminal neuralgia (TN) who underwent SPGR-MRI and 3D-TOF-MRA from August 1993 to October 1996, were found to have vascular compression caused by a tortuous vertebrobasilar system (TVBS). They were mostly males, demonstrated left-sided predominance, and had ipsilateral hemifacial spasm, compared with other 52 patients whose offending arteries were either superior cerebellar artery (SCA), anterior inferior cerebellar artery (AICA)or posterior inferior cerebellar artery (PICA). The patients who showed vascular compression by TVBS, presented an artery which compresses and dislocates the rootentry zone (REZ) of the trigeminal nerve, presses the brain stem at REZ and simultaneously compresses the REZ of the facial nerve. In addition, the diameters of the two branches of vertebrobasilar artery were not equal. These features indicate that the atherosclerotic change of the offending artery in TN caused by TVBS is more severe than that caused by SCA, AICA or PICA. This change causes an irregular running of artery which leads a strong compression of the trigeminal nerve REZ and of the brain stem. Consequently, the facial nerve REZ is severely affected leading to the presence of tic convulsif in TN caused by TVBS.

Detection of vertebrobasilar intracranial stenoses: transcranial Doppler sonography versus angiography

Vertebrobasilar intracranial stenoses seem to carry a higher risk of brain stem ischemia than proximal vertebral artery stenoses. Our aim was to assess the value of transcranial Doppler sonography versus angiography in detecting and quantifying these intracranial stenoses. All consecutive patients who underwent transcranial Doppler sonography prior to angiography from 1989 to 1994 and whose sonograms showed a stenosis of greater than 50% of one vertebral artery (21 cases) or of the basilar artery (eight cases) were included in the study. These patients were compared with 60 other consecutive stroke patients studied via transcranial Doppler sonography prior to normal vertebrobasilar angiography The transcranial Doppler sonographic criteria for stenosis were a peak systolic frequency shift greater than 2 KHz. A tight stenosis was identified by this pattern combined with direct and reverse low frequencies of high spectrum energy. The sensitivity of transcranial Doppler sonography using a peak systolic frequency shift in diagnosing stenoses reached 80% and its specificity was 97% if only atheromatous stenoses were considered. The main diagnostic failures concerned bilateral stenoses or contralateral occlusion, tandem lesions, and upper basilar artery stenosis. Transcranial Doppler sonography underestimated the degree of stenosis compared to angiography in 55% of the cases. We conclude that transcranial Doppler sonography is accurate in recognizing a stenosed vessel in the intracranial vertebrobasilar circulation, but if this finding will alter therapy, the examination must be complemented by magnetic resonance angiography.

Usefulness of magnetic resonance imaging in diagnosing vertebro-basilar insufficiency

To estimate the usefulness of magnetic resonance imaging (MRI) in diagnosing vertebro-basilar insufficiency (VBI), 41 VBI patients with vertigo or dizziness and 26 subjects without vertigo or dizziness (as control) were examined by MRI. Sixty-eight percent of the VBI group and 12% of the control group showed a large difference between the right and the left vertebral artery diameter, the incidence being significantly higher in the VBI group. Thirty-nine percent of the VBI group and 12% of the control group had lacunar infarction in the brain stem, of which the incidence was significantly higher in the VBI group, MRI can be recommended to diagnose VBI providing information on both blood vessel disorder and ischemic changes in the brain.

Bilateral ophthalmoplegia: an unusual sign of the top of the basilar artery syndrome

Bilateral ophthalmoplegia may be an unusual sign of vertebrobasilar ischemia. We report the cases of two patients (75 and 73 years old), who suddenly developed drowsiness, bilateral ophthalmoplegia with bilateral ptosis and mild right hemiparesis. In both patients, MRI revealed bilateral thalamic and midbrain infarcts, ECG showed the presence of atrial fibrillation and Doppler study of the extracranial and intracranial vertebral arteries found no significant alterations. Ischemia involving the midbrain and thalamic paramedian regions may cause bilateral ophthalmoplegia and consciousness disturbances. In these two cases, the most plausible etiologic mechanism was cardiac embolism, and the prognosis for bilateral ocular palsy was poor.

Biomechanical effects of experimental transluminal angioplasty

Surgical treatment of vertebrobasilar circulation disorders includes percutaneous transluminal angioplasty more often recently. However, the biomechanical aspects of transluminal angioplasty have not been studied sufficiently so far. 148 left and right vertebral artery segments were taken from 24 autopsy subjects (14 male and 10 female) aged from 20 to 75, who had neither systemic nor cerebrovascular lesions. Biomechanical examination and experimental transluminal angioplasty (ETA) of the tubular segments of vertebral artery (VA) were carried out by the special equipment developed for this purpose. The data were obtained using telemetrical, morphometrical and hystological methods. The biomechanical properties taken in the conditioned physiological rate are different for each segment of the VA. The stiffness of VA wall increases with age (mainly after 40 years), particularly in segments V1 and V3. Nevertheless, after high intravascular pressure application the diameter response of VA to intravascular fluid pressure increases if sufficient structural damage of the arterial wall was made.

Multiple cerebral arterial occlusions in a young patient with Sjögren's syndrome: case report

We describe a case of a young patient with multiple occlusions of major cerebral arteries and Sjögren's syndrome. This 17-year-old female patient experienced repeated transient ischemic attacks of right hemiparesis, speech disturbance, and unconsciousness. Angiography revealed progressive occlusion of the bilateral carotid and vertebral arteries. Examinations, including a serological test, a rose bengal test, Ga scintigraphy, and a biopsy of the parotid gland, indicated Sjögren's syndrome. The patient was successfully managed with bypass surgery. Patients with Sjögren's syndrome may experience progressive occlusion of the major cerebral arteries resembling that of moyamoya disease.

Anatomy of segmental duplication in the human basilar artery. Possible site of aneurysm formation

Segmental duplications of the basilar artery, previously reported exclusively as anatomical variations, owe their clinical interest to the possible association with aneurysms localized at the junctions of the fenestrated segments. The morphological characteristics of 5 cases of basilar artery segmental duplication without aneurysms, found at autopsy, are reported. In 3 of these the proximal junction of the fenestrated segment was studied with scanning electron microscopy and morphometry. In all cases the tunica media of the medial wall of the 2 branches showed a progressive thinning towards the junctions of the fenestrated segments and a small muscular gap at their apex. The limited medial defect might be embryologically ascribed to the persistence of the morphological individuality of the tunica media of the 2 branches at the point where the fusion of the primitive longitudinal neural arteries stopped. The review of the literature shows that the morphology of the junctions of the fenestrated segments is in conformity with that of the intracranial arterial bifurcations. For this reason the basilar artery fenestration exposes to the blood flow a new distal bifurcation where the same etiologic factors that are still under discussion in the origin of saccular intracranial aneurysms may be active.

Protection by Iloprost (stable analogue of prostacyclin) of endothelial damage due to chronic vasospasm in dogs: an electron microscope study

The resolution of cerebral vasospasm and protection of endothelial damage by Iloprost was evaluated with multicisternal injections. Sixteen adult mongrel dogs (18-20 kg) were assigned to one of three experimental groups. All animals received a total amount of 15 ml fresh unheparinized arterial blood via three injections into the cisterna magna. Selective vertebral angiography was performed on day 0 and subsequently blood injections were performed on the 2nd and 3rd days after the first injection. On the 7th day angiography was reperformed to determine the chronic vasospasm. The first group (5 dogs) was the control group and received intrathecal saline which was equal to the amount of saline in which Iloprost was diluted. The second group (5 dogs) did not receive any treatment until the 7th day. The third group (6 dogs) received Iloprost intrathecally (total 10 micrograms kg-1). In the first two groups angiographic vasospasm was prominent. For the second group intraarterial Iloprost was given on the 7th day in order to evaluate its acute effect. However there was no evidence of resolution of vasospasm. In the third group, resolution of vasospasm was verified on angiograms. Electron microscope studies of basilar arteries of the first two groups revealed degenerative changes of the endothelial cells which were separated from each other and the elastic lamina was irregularly arranged. In the intrathecal Iloprost-treated group there was little thickening in the elastic lamina and the endothelial cells were almost normal in structure. These results can be considered as the evidence of the prophylactic effect of Iloprost given by the intrathecal route in the prevention of chronic cerebral vasospasm.

[Pseudotransitory ischemic attacks as the initial symptom of multiple system atrophy]

A 59-year-old man presented with an 18-month history of episodes of visual disturbance and dysphagia in association with gait unsteadiness and leg weakness lasting between 45 and 120 min. These episodes were interpreted as vertebrobasilar transitory ischemic attacks. However, they had been preceded by impotence for 6 months. Autonomic function tests remained normal until the age of 62 years when the patient developed documented orthostatic hypotension. Parkinsonism was precipitated by neuroleptic treatment at the age of 59 years, at which time pyramidal signs were evident. The patient was unable to tolerate levodopa preparations and subsequently developed the full clinical picture of pathologically proven multiple system atrophy, dying at age 65, 7 years after his first symptom.

[Early and middle latency auditory evoked potentials in vertebrobasilar strokes]

Brainstem auditory evoked potentials (BAEPs) and middle-latency auditory evoked potentials (MLAEPs) have been recorded in 67 patients who had a stroke in well-defined territories of the vertebral and basilar arteries. Either CT scan or MRI have been performed in all cases. BAEPs were abnormal in 41/67 patients and MLAEPs were abnormal in 25/39 patients. BAEPs abnormalities were either bilateral (29/41 cases) or unilateral (12/41 cases). All components of BAEPS were unilaterally absent in four cases and bilaterally in one case. Pa component of MLAEPs was unilaterally delayed or reduced in five cases and bilaterally in 20 cases. Considering the topography of the infarct as shown by CT scan or MRI: medulla oblongata (13 cases): BAEPSs were normal in nine cases; pons (24 cases): BAEPs were abnormal in 16 cases; MLAEPs were abnormal in ten of 15 patients whose BAEPs were abnormal as well; mesencephalon (seven cases): BAEPs were abnormal in only two cases, and MLAEPs were abnormal in two cases one of which BAEPs were normal; in patients with diffuse infarctions either BAEPs or MLAEPs or both were abnormal in all cases. Stimulation of the ear ipsilateral to the lesion disclosed more BAEPs or MLAEPs abnormalities than stimulation of the contralateral ear.

A pathological study of intracranial posterior circulation dissecting aneurysms with subarachnoid hemorrhage: report of three autopsied cases and review of the literature

Three autopsied cases of dissecting aneurysms with spontaneous subarachnoid hemorrhage of the intracranial posterior circulation are reported, and the literature is reviewed to investigate the pathological characteristics and pathogenesis of this lesion. The location and pathological features of the aneurysms were different in each of the cases presented. Subadventitial hemorrhage associated with the subarachnoid hemorrhage, multiple noncontiguous intramural hemorrhages, and new vessels in and around the arterial wall were noteworthy findings in our series. All 20 reported autopsied cases of the vertebrobasilar artery have a dissection between the media and adventitia with a rupture site in the thin adventitia. Seventeen of them had disruption of the entire arterial wall, but the remaining three cases had no apparent luminal connection. The clinicopathological features of this disease are various. On the basis of the pathological investigations of these reported cases, the pathogenesis of this lesion is discussed. Intramural hemorrhage associated with dissection without luminal connection should not be disregarded as a causative factor.

Repeat angiography and magnetic resonance imaging (MRI) of dissecting aneurysms of the intracranial vertebral artery. Report of four cases

We here present 4 cases with dissecting aneurysm (DA) of the intracranial vertebral artery, who were followed up by repeat cerebral angiography and MRI. The patients consisted of 2 males and 2 females, and the mean age was 43 years. Two cases were associated with polyarteritis nodosa (PN) and hypertension, respectively. Three of the cases developed subarachnoid haemorrhage (SAH), while the other one suffered from lateral medullary syndrome. In cerebral angiography, "pearl and string" signs were revealed in all cases, while a "double lumen" indicating a true diagnostic sign of DA was demonstrated in only one case. Repeat angiography showed that a bleb formation with a bulging of the aneurysmal sac was seen in 2 cases, and an irregularity of the wall in one case. On the other hand in one case, the ectatic part shrank, while the stenotic part was restored. In magnetic resonance imaging (MRI), a hyperintensity mass on T 1-weighted image (T 1-WI) adjacent to flow void suggesting either an intramural haematoma or a linear shape hyperintensity on T 1-WI were demonstrated in 3 cases. In the follow up MRI done in 2 cases, a serial change in the intensity from iso-intensity to hyperintensity on T 1-WI was observed in one case suggesting intramural haemorrhage, while an enlargement of the ectasic flow void was seen in the other case. Three of 4 cases were operated on by trapping of the aneurysms. One, who had systemic vascular diseases due to PN, and repeat angiography showed a regression of the aneurysm, was conservatively treated.(ABSTRACT TRUNCATED AT 250 WORDS)

Topographic EEG analysis in two patients with basilar thrombosis

The EEG activity of two patients with occlusion of the vertebral and basilar arteries was analyzed. Power maps, peak power frequency, and field power differences during both photic drive and verbal command were evaluated. Clinical findings of one patient fit the criteria of locked-in syndrome. Photic stimulation and event related desynchronization paradigm was used for testing the reactivity of EEG. Averaged EEG epochs during intended movement after verbal command showed significant alpha and sub-alpha power reduction. Regional differences of EEG reactivity were assumed secondary to the underlying hemispheric infarcts. Awareness of the patient in a locked-in state was documented by EEG analysis. In the second case permanent vegetative state was associated with a nonreactive rhythmic alpha pattern. Time sequence analysis of power ratios showed spontaneous alternating activity of alpha and sub-alpha generators. The authors conclude that pseudo-periodic fluctuation of alpha activity reflects partial preservation of thalamo-cortical connections.

Computerized electroencephalographic, polysomnographic, transcranial ultrasound and morphopathological research in vertebro-basilar strokes

This paper contains a clinical, classical electroencephalographic and computerized electroencephalographic (by original methods) study of 271 cases with vertebro-basilar strokes, all the cases being verified by transcranial Doppler ultrasound investigations and some of the patients by morphopathological studies. In the first part, the standard EEG modifications in relation with the clinical pictures and with the affected arterial field are presented. In the second part, the aspects of the computerized EEG recordings with the carrying out of the cortical EEG mappings which have brought important contributions in setting down the topography of the infarctions are discussed. The third part presents the results of the polysomnographic recordings of the 70 selected cases with ischaemic vertebro-basilar attacks without disorders of consciousness (32 cases), with attacks accompanied by symptomatic hypersomnias (13 cases), with ischaemic attacks accompanied by insomnia (5 cases) and with ischaemic attacks with disorders of consciousness (20 cases). The opinion of the authors on the possible relations between the disturbances of the vigilance, the perturbations of the polysomnographic organization of sleep-wakefulness cycles (with the realisation of some interesting competitive dysfunctions between the three states of vigilance) and the electrographic anomalies are discussed.

Evidence for the participation of vascular endothelium originated humoral factors to cerebral vasospasm

Vascular endothelium synthesizes mediators which either cause vasorelaxation or vasoconstriction. The purpose of this study is to investigate the role of these mediators in the pathogenesis of cerebral vasospasm. An inhibitor of endothelium-derived relaxing factor is haemoglobin; endothelium removal by triton X-100 and endothelin-1 caused narrowing in the diameter of basilar artery of the rabbit. The pathological, ultrastructural investigations and computerized tomography images are in accordance with this finding. These results indicate that not only an increase in vasoconstrictor mediator level but also the lack of endothelium-derived relaxing mediators are responsible of the spasm of the basilar artery.

Distal ligation and revascularization from external carotid to vertebral artery with radial artery graft for treatment of extracranial vertebral artery dissection. Report of a case

We present a case of dissection of the extracranial vertebral artery with prominent occipital pain and elements of the lateral medullary syndrome. Arteriography showed a string and pearl sign. Magnetic resonance imaging allowed visualization of an intramural thrombus associated with a narrow vascular lumen. The distal portion of the diseased artery was ligated and vascular reconstruction using an interposed radial artery graft was performed. Pathological studies confirmed the diagnosis. The diagnostic roles of angiography and magnetic resonance imaging, and therapeutic strategies are discussed.

Vein graft replacement of the distal vertebral artery

Vein graft reconstruction of the cervical portion of the vertebral artery has been commonly used for the treatment of atherosclerotic arterial disease. In this article, we describe two instances of vein graft replacement of the distal portion of the vertebral artery. In the first case, the vein graft was placed from C2 transverse foramen to the intradural portion of the vertebral artery to replace an artery abnormally encased and involved by meningioma. The grafting was done in this case to preserve the cerebrovascular reserve in a young patient. In the second case, a vein graft was placed from the extradural C1 portion to the intradural artery beyond the posterior inferior cerebellar artery. This was done to replace a segment of the artery involved by a giant aneurysm, which could not be clipped without occluding the parent artery. In this case, the vein graft replacement was necessitated by changes of somatosensory evoked potentials after the aneurysm was clipped, demonstrating the need to preserve the patency of the artery. Vein graft replacement of the proximal intradural vertebral artery is feasible by the combination of standard cerebro-vascular techniques and the exposures afforded by skull base surgery.

Distribution of thrombotic lesions in the cerebral arteries in spontaneous occlusion of the circle of Willis: cerebrovascular moyamoya disease

In this paper, we have attempted to discuss the role of thrombogenesis in the formation or progression of the obstructive vascular lesions in so-called "spontaneous occlusion of the circle of Willis" (cerebrovascular Moyamoya disease) through histopathological observation on the cerebral arteries in this disease. Using the autopsy cases with this disease (28 cases), we examined the histological details of the cerebral arteries, including the circle of Willis and its major branches, to describe the distribution and the nature of thrombotic lesions. Thrombotic lesions were observed in up to 15 out of the 28 cases (54%). Predominant sites of the thrombi were the internal carotid arteries, the posterior communicating arteries, and the posterior cerebral arteries. The high incidence of thrombi formation as well as their distribution which closely correlated with the progression of the intimal lesion of this disease strongly suggested the importance of abnormal thrombogenesis as an etiologic factor in this disease.

[Repeated treatment of subtotal vertebrobasilar stenosis with tissue plasminogen activator (tPA)]

We report on the successful repeated treatment of a patient with rapidly progressive severe brain-stem stroke by application of I.V. tissue plasminogen activator (tPA). This treatment twice led to a prompt remission of severe brain-stem symptoms, although a permanent therapeutic success could not be achieved. Unfortunately, the patient died a few days later from pneumonia and sepsis. Necropsy revealed bilateral partial brain-stem infarctions and a subtotal stenosis of the vertebrobasilar junction with superimposed fresh thrombus. The clinically dramatic response to tPA indicates that this type of treatment is potentially successful in high-grade subtotal basal cerebral artery stenosis with progressive stroke symptoms. In particular, application of tPA should be considered if stroke progression cannot stopped by therapeutic heprinization. A prospective randomized oligocentric study is advocated.

[Pathological and etiological studies on cerebral infarction in the vertebrobasilar arterial system]

25 cases of cerebral infarcts in vertebrobasilar arterial system are reported. Those were divided into 4 groups: 1. Embolism (10), the causes were NBTE, pulmonary infarct, rheumatic or congenital heart disease, coronary artery disease, respectively, and 2 unknown. 2. Thrombosis (5), the causes were arteriosclerosis, vascular malformations in the basal part of cerebrum. 3. Inflammatory infarcts (3), those were verified from tuberculosis, syphilis and aspergillosis respectively. 4. Lacunar infarcts (7), the causes were considered from hypertension. Pathologically, it was noticed that the location of embolism often situated at the terminal of basilar artery, and that if the embolism was completely obliterated, often a hemorrhagic infarction would follow. But the thrombosis in basilar artery, even the lumen was completely obliterated, any infarct would not follow, if the related collateral circulation was satisfactory. Clinically, the embolism in basilar artery often showed sudden onset, and that the symptoms of brain stem would aggravate quickly, but the thrombosis in basilar artery, if the collateral circulation was satisfactory, and symptom of brain stem might not follow.

[Topographic correlation between basilar artery occlusion and cerebellar involvement--a clinicopathological study]

Nineteen patients (15 men, 4 women) with occlusion of the vertebrobasilar artery were studied in order to identify possible pathomechanism and to define the site of arterial occlusion and the topography of ischemic lesion of the cerebellum. Their mean age at onset was 66.7 years and the final clinicopathological diagnosis were thrombosis of the basilar artery (BA) in 15 patients and embolism in 4. The occlusion of the BA was contiguous to that of the vertebral artery in ten patients. Of these, the occlusion was localized to the caudal portion of the BA in two, to the middle portion in six, and extended to the rostral portion in two. In eight patients, the arterial occlusion was restricted to the BA. Occlusions of the middle portion were observed in four and that of rostral portion in two; in the other two patients, the whole BA was occluded. In one patient, there was no occlusion in the vertebro-basilar artery at the postmortem examination, but infarctions of the base of pons, bilateral cerebellar hemispheres and occipital lobes were confirmed, suggesting recanalization of the occluded BA. Cerebellar lesions were observed in all nineteen patients. Involvements of the area supplied by the superior cerebellar artery (SCA) were found in seventeen, while that of the posterior inferior cerebellar artery (PICA) only in ten. Eight patients had cerebellar lesions supplied by both SCA and PICA. These facts suggest that cerebellar lesions are rather frequent and the SCA areas are more involved than those of the PICA in fatal patients with occlusion of the BA.(ABSTRACT TRUNCATED AT 250 WORDS)

[Neurological manifestations in the vertebro-basilar system suggesting pregnancy toxemia]

Early CT scan showed a large hypodensity throughout midbrain. Brainstem auditory evoked potential showed initially an abolition of III and V pikes suggesting brainstem injury. Two days later neurologic examination and brain stem auditory evoked potential returned to normal. CT scan performed three weeks after the onset was normal. These finding suggest a vasospasm; in this case betasympathomimetic agents given two weeks before the onset of toxemia for preterm labor could lead to the vasospasm.

Clinical signs associated with megadolichobasilar artery anomaly

The elongation and ectatic course of the basilar artery (BA), called megadolichobasilar artery anomaly (MDBAA) is a macroscopic description of a neuroradiologic finding. Clinically ischemic brain stem syndromes and peripheral cranial nerve disturbances especially of the trigeminal and facial nerves, cerebellar dysfunction and CSF circulation disturbances are observed. Seldom a subarachnoid hemorrhage is proven. In CT and MRI often a tumorlike mass with a ringlike contrast enhancement combined with a nonhomogeneous lesion due to partial thrombosis, is detected. Angiography in most cases shows fusiform dilatation of the BA, elongation of the top of the basilar trunk, asymmetric tortuosity or dislocation of the irregular shaped wall of the BA. Fifteen patients within the last 12 years are demonstrated. The role of reticular fiber deficiency in the media and defects of the elastic lamina as the basis of these malformations is reported. We discuss coincidental findings of MDBAA with atherosclerosis, congenital factors causing generalized vasculopathy, metabolic disturbances in form of so called inborn errors of metabolism and endocrine deficiencies. In cases with clinical signs the morbidity is remarkably high.

Fatal bilateral vertebral artery dissection in a patient with cystic medial necrosis

A 38-year-old man experienced severe neck pain while playing badminton. This was followed by symptoms of vertebrobasilar ischaemia, seizure and coma. Autopsy showed bilateral vertebral artery dissection and cystic medial necrosis.

[An autopsy case of atypical hanging: were arteries and air passage obstructed?]

A housewife hanged herself with her left foot on a washstand and her right foot above the floor. The ligature mark encircled once horizontally at the height of the laryngeal prominence (horizontal part), crossed at the front of the neck, rose to the posterior regions of the mandibular angles and extended upward to the preauricular regions (ascending part). Petechial haemorrhage was in the conjunctivae and froth was in the air passage. Vertebral arteries are not obstructed by the compression of the horizontal part (Brinkmann et al., 1981). Vertebral arteries are possibly not obstructed by the traction of the ascending part (experiment on our own necks). An air passage is not obstructed by the compression of the horizontal part (Langreuter, 1886; Strassmann, 1922). Obstruction of an air passage by typical hanging is removed by putting the bent head to upright position (Langreuter, 1886). From these experimental observations we clarified that in our case the vertebral arteries and air passage had very possibly not been obstructed by the hanging while 70-80% of her body weight, i.e. 40-45 kg, had loaded on the neck. The force to obstruct the arteries and air passage by hanging, which has been quoted in texts and articles in Japan, is absolutely due to the value for "typical" hanging.

[Clinical and pathologic-anatomic findings in acute basilar thromboses. A study of 30 autopsy verified cases]

In a retrospective study of 30 cases with fatal basilar artery thrombosis we compared clinical and autopsy findings for clinicopathological correlation. There are only few clinical symptoms which point to a definite localisation and extent of thrombosis or cerebral infarction. In most cases loss of consciousness and hemi- or tetraparesis are due to pontine or mesencephalic infarction. Palsy of the facial nerve suggests infarction of the pons. The incidence of cranial nerve involvement is too low to allow localisation of infarction. There was no case showing infarction of the diencephalon or the medulla oblongata when pontine or mesencephalic structures were intact. Moreover, these infarctions remained clinically silent. No clinical predictors of outcome could be defined. Even in patients without detectable impairment of consciousness or stenosis of the vertebral arteries, the disease may prove fatal.

Intimal fibroelastic thickening--its etiological significance in juvenile cerebral infarction. Case report

Recurrent occlusive stroke of the vertebrobasilar system is reported in a 16-years-old man. Multiple arterial occlusions, segmental stenosis, or irregular dilatation were found in the angiography involving both the intra- and extracranial vertebro-basilar arteries. Surgical specimen of the extracranial vertebral artery with localized irregular lumen disclosed fibroelastic thickening of the intima with mural thrombus, which were thought to be an embolic source. Etiological significance of this intimal lesion in juvenile cerebrosvascular accident is discussed.

Transcranial Dopplersonography of the vertebro-basilar system

This is the first investigation of distances, angles and locations of the vascular system in the posterior fossa. The distances from the skin surface of the neck, where a Doppler probe is positioned for transforaminal insonation, to the brainsystem have been measured in sagittal MRI pictures. The mean distance from the insonation point to the beginning of the basilar artery (BA) is 66.6 mm in males, 58.8 in females. The distance to the end of the BA is 90.0 and 80.4, respectively. These distances are relevant for locating the vertebral and basilar arteries. The insonation angles to the VA and BA range from 20 degrees to 30 degrees. Correlations with Doppler findings are discussed.

Brain stem glioma mimicking progressive basilar artery thrombosis

Images

Basilar artery disease--clinical outcome and Doppler sonographical follow-up

In the past 5 years we have investigated 29 patients with symptomatic basilar artery stenoses (14 cases) and occlusions (14) and a patent primitive trigeminal artery with thin-calibered basilar and vertebral arteries (1) using directional continuous-wave Doppler sonography of the vertebral arteries. A total of 19 patients survived, and 17 of them were clinically and sonographically reexamined after 40.4 +/- 15.8 months (mean +/- SD). Among the 8 patients with basilar stenoses, 6--with no further transient ischemic attacks (TIAs) in the interval--exhibited an increase in the summed modified Pourcelot indices (relative end-diastolic flow velocities) of the vertebrals by 0.18 +/- 0.16; the other 2 showed a decrease by 0.26 each, in 1 case temporally related to a TIA, in the 2nd case without further clinical deterioration. In the 8 survivors with basilar occlusions, 5 remained--by sonographic criteria--unchanged with summed modified Pourcelot indices of the vertebrals of 0.00, while 3 patients exhibited a slight increase in the summed modified Pourcelot indices of 0.13 +/- 0.03. While the difference between the outcome of subsets of patients treated with regimens of 30,000-40,000 units heparin/day or phenprocoumon and less radical drugs were statistically not significant, the former regimen appeared clinically more efficacious in preventing further deterioration in approximately two-thirds of the patients affected. Due to the potential recurrence of neurological symptoms, a treatment period with phenprocoumon of 6 months after discharge from hospital appears justified. Due to these therapeutic efforts, approximately half of the patients initially affected survived with no or only a mild neurological deficit.(ABSTRACT TRUNCATED AT 250 WORDS)

The bull's-eye sign of extracranial cervical aneurysms

Extracranial, cervical aneurysms and arterial thrombosis are uncommon entities. In most cases, they have diagnostic clinical presentations. However, on occasion the history and physical findings do not clearly suggest their presence. In these cases, postcontrast computed tomography scans can aid in rapidly establishing the correct diagnosis by revealing a "bull's-eye" appearance within the mass (vessel lumen). The diagnosis is less difficult to make when the involved vessel is the carotid artery, because this artery is routinely identified on postcontrast computed tomography scans and the lesion can be easily placed along its course. The vascular origin of such a lesion is not usually evident on computed tomography if the process does not lie along the course of a major vessel. In these cases, the bull's-eye sign can establish the diagnosis so that prompt consideration can be given to angiography and therapy.

[Clinical course, electrophysiologic monitoring and neuroradiologic findings in acute basilar artery thrombosis and local fibrinolytic therapy]

The development of new catheter materials and techniques has made it possible to perform local intraarterial fibrinolysis in the region of the basilar artery in case of thrombotic arterial occlusions. We present the case of a 27-year old patient suffering from thrombosis of the basilar artery in whom local fibrinolysis was performed. The clinical course is demonstrated in respect to imaging methods (angiography, CT and MRT) and electrophysiological monitoring.

[Neuro-otologic symptoms in a case of arteriography and autopsy-verified basilar artery thrombosis]

A case report on a 26 years old woman, who was admitted for a pontobulbar vascular accident. She took oral anticoncipients since 10 years without any control. Vertebral angiography confirmed the basilar artery thrombosis. Otoneurologic investigation was three times performed. The cochleovestibular alterations were in accordance with the neurologic signs and demonstrated the level and extension of the pathologic process. The autopsy confirmed the clinical diagnosis.

Vertebrobasilar insufficiency. Part 2. Microsurgical treatment of intracranial vertebrobasilar disease

Posterior circulation transient ischemic attacks have an associated risk of subsequent infarction of approximately 5% per year. Intracranial vertebrobasilar thrombo-occlusive lesions appear particularly likely to result in repetitive ischemic symptoms and in infarction due to hemodynamic insufficiency. The authors present their experience with 45 patients with symptomatic intracranial vertebrobasilar vascular disease despite maximal medical therapy. The specific operative approaches for intracranial vertebral artery endarterectomy and extracranial to intracranial posterior circulation revascularization procedures are outlined.

Vertebrobasilar insufficiency. Part 1: Microsurgical treatment of extracranial vertebrobasilar disease

Extracranial vertebrobasilar artery thrombo-occlusive disease may cause repetitive transient ischemic episodes and, less frequently, brain-stem or cerebellar infarction. This report describes 40 patients who experienced repetitive vertebrobasilar ischemic symptoms despite maximal medical therapy. The natural history, pathogenesis, and treatment options for each causative lesion are reviewed. The operative approaches to symptomatic disease of the proximal vertebral arteries, arterial compression by cervical osteophytes, traumatic lesions of the vertebral arteries, and thrombo-occlusive pathology of the distal extracranial vertebral arteries are outlined. Specific anesthetic and surgical techniques that have proved successful while achieving zero operative mortality and low perioperative morbidity rates are reported.

[Vertebrobasilar insufficiency of prenatal origin: a case report]

The case of a newborn presenting from birth with arthrogryposis multiplex congenita resting mainly on the legs, severe hypotonia, consciousness anomalies, clonic fits, recurrent apnea and bradycardia, absent sucking and swallowing is described. At the age 4 months a further episode of apnea and bradycardia was followed by death. The neuropathologic analysis disclosed a number of bilateral, cystic and symmetric infarcts in the thalamus and hypothalamus, spreading caudally to the tegmentum of the mesencephalon and the pons. Such distribution of lesions does suggest a vascular topography, i.e. in the territories supplied by branches of the vertebro-basilar arteries. There was light clinical and neuropathological evidence of prenatal occurrence of the vascular injuries, possibly at the end of the 7th month by a defective arterial perfusion of the fetus due to protracted menaces of premature birth. We would outline the existence and frequency of the thalamic and dorsal brain stem necrotic involvement by acute anoxia-ischemia occurring in the third trimester of gestation or at birth, and the relative peculiarity of their clinical picture.

Asymptomatic bruit, carotid and vertebrobasilar transient ischemic attacks--a clinical and ultrasonic correlation

One hundred patients with asymptomatic carotid bruit or transient ischemic attack (TIA) underwent continuous-wave Doppler (CWD) and real time ultrasound (RTU) testing of their cervical carotid arteries. After ultrasonic studies, 51 patients also underwent bilateral carotid angiography. There was 95% agreement between CWD and angiography for the diagnosis of a significant (greater than 50%) stenosis. The RTU diagnosis of a normal or occluded vessel was correct in 100% of cases. Seven plaques appreciated on RTU may not have been large enough for detection by angiography. In this small series, ulceration confirmed pathologically was more reliably predicted by RTU than by cerebral angiography. Significant ipsilateral carotid plaques occurred more often in patients with amaurosis fugax than in patients with hemispheric TIAs. Ipsilateral plaque ulceration occurred in 50% of symptomatic carotid bruits, but in only 10% of asymptomatic carotid bruits. Plasma concentrations of total cholesterol were significantly higher in TIA patients with carotid stenosis than in controls.

Vertebral artery injury and cerebellar stroke while swimming: case report

A twenty-five year old woman suffered the acute onset of dysequilibrium followed by headache, nausea, vomiting, vertigo, and slurred speech while swimming. Brain imaging revealed a right cerebellar infarct. Intravenous digital subtraction angiography showed a hypoplastic right vertebral artery and focal narrowing of the dominant left vertebral at the level of the C1-C2 junction. The patient was treated with aspirin and dipyridamole and immobilized for two weeks. She achieved almost complete recovery. Repeat angiography showed resolution of the left vertebral artery defect. Other cases of posterior circulation infarction associated with head turning during sports and ordinary activities are reviewed.

Pathology and pathophysiology of brain ischaemia

The current views on the pathophysiology of cerebral ischaemia have recently been challenged by the new experimental results and animal models devised in recent years. These data are briefly reviewed. Ischaemic macroscopical and microscopical lesions in the human brain are outlined. Ischaemic changes can be either regional or total. The types, topography and aetiology of cerebral infarcts, lacunes and venous infarcts are described. The consequences of marked or total ischaemia affecting the whole cerebral blood supply are mentioned.