Proper management of the rotational vertebral artery occlusion secondary to spondylosis

A 66-year-old man with cervical spondylosis noticed severe vertigo when turning his head to the right. He underwent subclavian arteriography elsewhere, which showed a block of the contrast medium in the right vertebral artery (VA) at the C5/6 level when the patient turned his head to the right. After referral to our institute, however, postcontrast CT scan revealed an attenuated shadow of the venous plexus around the right VA at the C3/4 level. Repeated selective angiography with rotation of the head after visualization of the entire VA verified the level of obstruction to be at C3/4. Resection of the C4 transverse process through an anterior approach with drilling of the C3/4 spondylotic spur of the uncinate processi completely resolved the arterial impingement and the symptom. When evaluating rotational VA occlusion, dynamic angiography with selective catheterization is essential in determining which level is affected. The postcontrast CT scan is also useful because it suggests the level even without head rotation.     

Rotational vertebral artery syndrome due to compression of nondominant vertebral artery terminating in posterior inferior cerebellar artery

Rotational vertebral artery syndrome (RVAS) is characterized by recurrent attacks of paroxysmal vertigo, nystagmus, and ataxia induced by head rotation. We report on a patient who developed atypical RVAS due to compression of the vertebral artery (VA) terminating in the posterior inferior cerebellar artery (PICA). A 59-year-old man suffered from vertigo and nystagmus induced by leftward head rotation and oculography showed right beating horizontal-torsional and downbeat nystagmus. Cerebral angiography showed hypoplastic right VA terminating in PICA without connection to the basilar artery. The basilar artery received its flow from the left VA only and branched out both anterior inferior cerebellar arteries. Cerebral angiography revealed a complete occlusion of the right distal VA at the level of the C1–2 junction when the head was rotated to a leftward position. In contrast, the blood flow through the left vertebral and basilar arteries remained intact while turning the head to either side. The hemodynamic compromise observed in our patient with RVAS indicates that isolated vertigo and nystagmus may occur due to transient ischemia of the inferior cerebellum or lateral medulla.     

Ischemic symptoms induced by occlusion of the unilateral vertebral artery with head rotation together with contralateral vertebral artery dissection--case report

We report a 45-year-old woman whose unilateral vertebral artery (VA) was potentially occluded with head rotation at the C1-C2 level and her ischemic symptoms suddenly appeared because of contralateral VA dissection. She noticed first pain around the posterior part of her neck on the right side, and then dizziness when turning the head to the right side. The dizziness disappeared immediately after her head returned to the natural position. Digital subtraction angiography (DSA) showed a string sign of the right VA. DSA and computed tomography angiography (CTA) showed high grade extrinsic compression of the left VA at the C1-C2 level with head rotation more than 90 degrees to the right. Three-dimensional (3D) CTA also showed clearly kinking of the left VA at the C2 neuroforamina. Her symptoms disappeared completely with conservative therapy, and recanalization of the right VA was also confirmed by 3D-CTA. 3D-CTA was thought to be valuable to diagnose and manage the rotational compression of the artery. VA dissection must be remembered to differentially diagnose the etiology of transient attacks of posterior circulation ischemia due to rotational contralateral VA occlusion.     

A case of severe stenosis of bilateral distal vertebral artery successfully treated with anastomosis operation]

A 65-year-old male complained of loss of consciousness for several minutes, transient diplopia and dizziness. He had no neurological deficits nor abnormalities in MR imaging. However, flow velocity of bilateral vertebral artery on ultrasonography indicated severe stenosis of bilateral distal vertebral artery. Brain angiography revealed severe stenosis of bilateral distal vertebral artery as well as occlusion of right middle cerebral artery (MCA). Single photon emission CT (SPECT: ECD-RVR method with acetazolamide loading) showed decreased cerebral blood flow and poor perfusion reserve in bilateral cerebellar hemisphere and right MCA territory. Superficial temporal artery-superior cerebellar artery (STA-SCA) anastomosis was performed. The patient turned out to have no episodes of unconsciousness attack, transient diplopia and dizziness after operation. Cerebral blood flow (CBF) in the posterior circulation was also improved. Evaluating quantitative CBF measurement by means of ECD-RVR method was useful for evaluating CBF. In cases who have severe stenosis of bilateral distal vertebral artery with complaints of vertebrobasilar insufficiency, STA-SCA anastomosis may be one of the most effective treatments.     

Intermittent vertebral artery compression caused by C1-root schwannoma: case report

Extradural schwannomas of the C1-root are extremely rare. As the tumor grows in size, it may compress surrounding neurovascular structures and cause symptoms. In the present case report, the left vertebral artery (VA) was severely compressed by the tumor, eliciting severe vertigo on turning the head to the right side and with neck extension. We report a 52-year-old man who presented with a history of intermittent episodes of severe vertigo on head movement that was caused by a C1-root schwannoma. The lesion was exposed through an extreme lateral transcondylar approach. At exposure the lesion was yellowish in color and was extradural in location lying between the markedly eroded C1-posterior arch and the compressed vertebral artery (V3) on the left side. The medial portion of the tumor was attached to the C1-nerve root. The tumor was excised enbloc with decompression of the VA. The patient's symptoms completely resolved immediately following surgery, with no recurrence of the symptoms at one year follow up. The vertebral artery may frequently be compressed by osteophytes in cervical spondylosis or due to other causes in the cervical spinal canal, but compression of the artery by C1 extradural schwannoma with vascular insufficiency is rare. Removel of the tumor and the resultant decompression of the artery can be facilitated by the extreme lateral approach as demonstrated by this case.     

Rotational vertebral artery syndrome

Whether the rotational vertebral artery syndrome (RVAS), consisting of attacks of vertigo, nystagmus and tinnitus elicited by head-rotation induced compression of the dominant vertebral artery (VA), reflects ischemic dysfunction of uni- or bilateral peripheral or central vestibular structures, is still debated. We report on a patient with bilateral high-grade carotid stenoses, in whom rightward headrotation led to RVAS symptoms including a prominent nystagmus. Three-dimensional kinematic analysis of the nystagmus pattern, recorded with search coils, revealed major downbeat nystagmus with minor horizontal and torsional components. Magnetic resonance angiography demonstrated a hypoplastic right VA terminating in the posterior inferior cerebellar artery, a dominant left VA, and a hypoplastic P1-segment of the left posterior cerebral artery (PCA) that was supplied by the left posterior communicating artery (PCoA). The right PCA and both anterior inferior cerebellar arteries were supplied by the basilar artery. The right PCoA originated from the right internal carotid artery. Color duplex sonography showed severe reduction of diastolic blood flow velocities in the left VA during RVAS attacks. The nystagmus pattern can be best explained by vectorial addition of 3D sensitivity vectors of stimulated right and left anterior and horizontal semicircular canals with slightly stronger stimulation on the left side. We hypothesize that in RVAS, compression of dominant VA leads to acute vertebrobasilar insufficiency with bilateral, but asymmetric ischemia of the superior labyrinth. With regard to RVAS etiology, our case illustrates a type of pure vascular RVAS. Severity of attacks markedly decreased after successful bilateral carotid endarterectomy.     

Intermittent vertebral artery compression caused by C1-root schwannoma: Case Report

Abstract

Extradural schwannomas of the Cl-root are extremely rare. As the tumor grows in size, it may compress surrounding neurovascular structures and cause symptoms. In the present case report, the left vertebral artery (VA) was severely compressed by the tumor, eliciting severe vertigo on turning the head to the right side and with neck extension. We report a 52-year-old man who presented with a history of intermittent episodes of severe vertigo on head movement that was caused by a Cl-root schwannoma. The lesion was exposed through an extreme lateral transcondylar approach. At exposure the lesion was yellowish in color and was extradural in location lying between the markedly eroded Cl -posterior arch and the compressed vertebral artery (V3) on the leftside. The medial portion of the tumor was attached to the Cl-nerve root. The tumor was excised enbloc with decompression of the VA. The patient’s symptoms completely resolved immediately following surgery, with no recurrence of the symptoms at one year follow up. The vertebral artery may frequently be compressed by osteophytes in cervical spondylosis or due to other causes in the cervical spinal canal, but compression of the artery by Cl extradural schwannoma with vascular insufficiency is rare. Remove! of the tumor and the resultant decompression of the artery can be facilitated by the extreme lateral approach as demonstrated by this case. [Neurol 2000; 22: 679-684]     

小脑后下动脉解剖变异致双侧小脑梗死2例报道并文献复习

目的 探讨小脑后下动脉(posterior inferior cerebellar artery, PICA)解剖变异致双侧小脑梗死的临床特征及发病机制。方法 对2例经颅脑MRI确诊的双侧小脑梗死患者采用CT血管造影(CTA)、磁共振血管成像(MRA)或数字减影血管造影(DSA)显示其头颈部血管,从而了解后循环血管的形态特征并复习相关文献。结果 病例1经DSA证实左侧椎动脉较细,远端管腔闭塞,通过右椎动脉代偿供血原左侧PICA供血区但欠充分,双侧PICA共同起源于右侧椎动脉。病例2经CTA证实右侧椎动脉较左侧明显细且远端显示欠清,MRA示双侧PICA共同起源于左侧椎动脉。结论 2例双侧小脑梗死患者均存在一侧椎动脉优势供血,且双侧PICA共同起源于该侧椎动脉。在该解剖变异基础上一侧椎动脉发生病变时可出现双侧小脑梗死。因此,在临床中出现双侧小脑梗死时临床医师不能忽略这一解剖变异基础。     

Bow hunter’s syndrome unmasked after contralateral vertebral artery sacrifice for aneurysmal subarachnoid hemorrhage

Bow hunter’s syndrome (BHS), or positional vertebrobasilar insufficiency, is a rare disorder characterized by positional stenosis or occlusion of the dominant vertebral artery (VA) with concordant signs and symptoms of brainstem ischemia. Many etiologies have been described, with the most common level of obstruction occurring at the craniocervical junction. The authors report acquired BHS after the patient’s contralateral VA was sacrificed for ruptured aneurysm. A 44-year-old man was referred to our institution for years of continued positional tinnitus, vertigo, and nausea. This symptomatology began 5 years prior, immediately after the patient’s right VA was endovascularly sacrificed to treat a ruptured VA aneurysm. From the time of treatment, right head turning caused instantaneous symptoms consistent with brainstem ischemia. Evaluations performed during the 5 year interim before referral included computed tomography angiography, MRI, and diagnostic cerebral angiography (DCA). All failed to identify a causal etiology. A diagnosis of BHS was made with dynamic DCA. With the patient’s head turned to the right, angiography of the left VA demonstrated a positional block. The patient underwent left VA decompression. Intraoperative dynamic DCA was utilized to demonstrate adequacy of decompression. The patient tolerated the procedure without complication. Symptomatology immediately completely subsided and remained absent at his 3 month follow-up. An acquired BHS should be recognized as a possible complication if VA sacrifice is considered for an unclippable or uncoilable aneurysm.     

Percutaneous transluminal angioplasty of extracranial vertebral artery stenosis--a case report

Due to improvement in intravascular therapeutic procedures significant stenoses of vertebral and basilar arteries can presently be treated by means of percutaneous transluminal angioplasty (PTA). The reported case was a 34-year-old man with symptomatic stenosis of the distal left vertebral artery and hypoplastic right vertebral artery. The patient underwent PTA and the lesion was sufficiently dilated. No complications occurred during or after the procedure. After a year duplex Doppler follow-up examination showed normal blood flow and patency of both vertebral arteries. PTA may prove to be a useful therapeutic option in patients with symptoms of vertebro-basilar insufficiency.     

Regional cerebral blood flow during an attack of vertebrobasilar insufficiency

Using technetium-99m-labeled hexamethylpropyleneamineoxime [( 99mTc]HM-PAO) and single-photon emission computed tomography, we measured changes in regional cerebral blood flow in a 58-year-old man during an attack of vertebrobasilar insufficiency. Angiography demonstrated compression of the left vertebral artery by the osteophytes of cervical spondylosis when the patient turned his head to the left. Measured in the orthostatic position while turning his head to the left during a typical attack of vertebrobasilar insufficiency, regional cerebral blood flow was significantly reduced in the left cerebellum and the right occipital region. Our study illustrates the capability of [99mTc]HM-PAO single-photon emission computed tomography to measure transient reductions in regional cerebral blood flow and to relate these changes to the pathophysiology of vertebrobasilar insufficiency.     

Bilateral vertebral artery occlusion associated with atlantoaxial dislocation due to os odontoideum]

A 17-year-old boy was hospitalized with transient consciousness disturbance on extension of the neck. At seven years of age, the patient developed delayed-onset posterior circulation stroke after the door struck him a mild blow on his forehead. A computed tomography scan revealed right cerebellar infarction with unknown etiology. He had been followed up without stroke recurrence and CT change until this hospitalization. Cerebral angiography disclosed bilateral vertebral artery occlusion at the C-2 level with the well-developed muscular collateral artery bypassing the occluded left vertebral artery. A cervical X-ray showed a posterior atlanto-axial subluxation with os odontoideum. Compression of the vertebral arteries due to mild trauma aggravating an atlanto-axial subluxation may have caused the bilateral vertebral artery thrombosis resulting in occlusion, and disturbance of the muscular collateral circulation on extension of the neck may have led to the recurrence of vertebrobasilar insufficiency. This is the first report of the angiographically confirmed bilateral vertebral artery occlusion with an established etiology in childhood.     

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.     

A case of bow hunter's stroke caused by non-dominant vertebral artery

Rotational movements in the territory of vertebrobasilar artery of the head and neck can induce vertebrobasilar insufficiency (VBI) or infarction. The term "bow hunter's stroke" or "rotational VBI" has been used to describe this clinical syndrome. In most cases, symptoms were provoked because of involvement of a dominant vertebral artery (VA) with hypoplasia or occlusion of the contralateral VA. The author presented a case in which bow hunter's stroke was caused by occlusion of a non-dominant VA ending in the posterior inferior cerebellar artery (PICA). Diagnosis of rotational VBI was based on stereotypical clinical symptoms related to head rotation and hemodynamic study of the effects of head rotation. VA compression was documented in dynamic ultrasonography including the disappearance of end-diastolic flow in extracranial portion of VA and marked reduction in blood flow velocity (more than 50%) in the intracranial portion of VA upon head rotation. We emphasize that rotational occlusion of this anatomical variation is an important cause of VBI. This may cause permanent neurological deficits if left undiagnosed.     

Surgical correction and SPECT imaging of vertebrobasilar insufficiency due to unilateral vertebral artery stenosis.

BACKGROUND AND PURPOSE: Incapacitating vertebrobasilar insufficiency is generally associated with bilateral vertebral artery disease, whereas unilateral vertebral artery stenosis usually is clinically silent. Regional brain perfusion has not been part of the routine evaluation of patients with vertebrobasilar insufficiency. This report describes two patients who had isolated unilateral vertebral artery stenosis operatively corrected to eliminate their incapacitating vertebrobasilar insufficiency. Hindbrain hypoperfusion was identified preoperatively and evaluated postoperatively, then correlated with patient presentation and response to revascularization. CASE DESCRIPTION: Two patients with incapacitating vertebrobasilar insufficiency presented with isolated unilateral vertebral artery stenosis with patent, nonstenotic internal carotid arteries. Hindbrain hypoperfusion was demonstrated by iodine-123-iodoamphetamine single-photon emission computed tomography preoperatively and demonstrated significant improvement following vertebral-carotid reimplantation. The patients' symptoms resolved following revascularization. CONCLUSIONS: Although unusual, unilateral vertebral artery stenosis can cause incapacitating vertebrobasilar insufficiency. These cases demonstrate the value of imaging with single-photon emission computed tomography to evaluate regional brain hypoperfusion and to evaluate objectively the results of therapy.     

An association between vertebral artery dominance and steno-occlusion of the vertebral artery segments: A retrospective angiographic study

ObjectivesThis study investigated whether there was a relationship between steno-occlusion of the vertebral artery (VA) segments and the dominant VA side.Materials and methodsAngiography results of 215 patients (146 men; 69 women) were retrospectively analyzed in this study. The patients were divided into three groups: dominant, non-dominant and co-dominant. These groups were compared according to the presence of steno-occlusion in the vertebral artery segments. The results were evaluatedusing X², Mann-Whitney U and Kruskal-Wallis tests. For correlation analysis, Spearman's Rho test was used.ResultsThe findings showed that 55 of 215 patients (25.6%) had a right dominant VA, and 103 (47.9%) had left dominant VA. There was no significant relationship between dominance and age or gender (p > 0.05). More vertebral artery stenosis (VAS) was found on the dominant side. However, a significant relationship only in the right dominant V1 segment (p = 0.044) was noticed. Hypoplastic VA was detected in 13 patients (6%). Most of the VAs (98.4%, n = 423) arose from the subclavian artery.ConclusionsIn conclusion, we found more vertebral artery stenosis on the dominant side than the co-dominant side, especially on the origin of the vertebral arteries. However, it was only significant on the right dominant V1 segment, regardless of age and gender of the patients (p > 0.05).     

Rotational vertebral artery syndrome: oculographic analysis of nystagmus

In four patients with rotational vertebral artery syndrome (RVAS), the initial nystagmus was mostly downbeat, with the horizontal and torsional components beating toward the compressed vertebral artery side (n = 3) or directed away (n = 1). Three patients showed spontaneous reversal of the nystagmus and two exhibited no or markedly diminished responses on immediate retrial of head rotation (habituation). The patterns of nystagmus suggest that RVAS may result from differing mechanisms.     

Palatal myoclonus secondary to vertebral artery compression of the inferior olive.

A 47-year-old male with a 5-year history of palatal myoclonus was found on magnetic resonance imaging (MRI) examination to have an ectatic dominant left vertebral artery that compressed the left inferior olive. Microvascular decompression effectively eliminated his symptoms. This case and a similar case presented here with an ectatic vertebral-basilar system illustrate the value of standard MRI in conjunction with magnetic resonance angiography (MRA) in evaluating palatal myoclonus, and they suggest a potential role for decompressive surgery when persistent, highly symptomatic inferior olivary ischemia or compression occurs.     

An 8-year-old boy with vertebral artery dissection with cerebellar ataxia featuring suspected vertebral artery hypoplasia

We report an 8-year-old boy with left vertebral artery dissection featuring cerebellar ataxia in which congenital vertebral artery hypoplasia was suspected as a predisposing factor in the dissection. The patient suddenly suffered from vertigo and vomiting while swimming, and he was brought to our department. The initial brain Computed Tomography (CT) demonstrated no abnormalities, and his symptoms disappeared the next morning. However, one month after onset, brain Magnetic Resonance Imaging (MRI) revealed ischemic changes (infarction) in the left cerebellum. Transfemoral angiography showed complete occlusion at the C2 portion of the left vertebral artery, suggesting dissection and diffuse narrowing of the proximal segment of the occlusion site. Three-dimensional CT angiography also revealed diffuse narrowing of the left vertebral artery from the bifurcation of the subclavian artery. He has since been living daily life without any difficulties. The detailed etiology of cerebral artery dissection remains unknown, but arterial anomalies should be considered as a predisposing factor.     

椎动脉起始位置与穿出颈椎横突孔高度关系的三维CT血管成像研究

目的通过三维CT血管成像(CTA)探讨椎动脉起始位置与穿出颈椎横突孔高度的关系。方法回顾性分析2017年3月至2019年3月河北医科大学第二医院神经外科行头颈上胸部CTA检查的480例患者的临床资料。将图像传输至图像后处理工作站进行骨质和血管重建,观察双侧椎动脉的起源、走行及穿出颈椎横突孔的高度。对于右侧椎动脉起源正常者,根据穿出颈椎横突孔的高度分为C₄、C₅、C₆组,每组随机选取10例分别测量右侧椎动脉起始位置至右侧颈总动脉起始的距离(L1)和右侧甲状颈干的距离(L₂),以L₁/(L₁+L₂)×100%计算椎动脉起始的相对位置。结果480例患者中,457例(95.2%)双侧椎动脉起源位置正常,均起源于锁骨下动脉,另23例(4.8%)起源异常,其中左侧椎动脉起源于主动脉弓19例、左侧颈外动脉1例;右侧椎动脉起源于右侧颈总动脉3例,且均合并迷走右锁骨下动脉。480例患者中,405例(84.4%)双侧椎动脉经C₆横突孔穿出;另75例(15.6%)穿出高度异常,其中左侧34例,经C₃、C₄、C₅、C₇横突孔穿出的分别有1、4、24、4例,直接入枕骨大孔1例;右侧41例,经C₃、C₄、C₅横突孔穿出的有1、14、26例。椎动脉起源异常的患者,左侧椎动脉起自主动脉弓的占比最高(19/20),且多数穿出颈椎横突孔的高度异常(18/19);右侧椎动脉均起自右侧颈总动脉合并迷走右锁骨下动脉(3/3),且穿出颈椎横突孔的高度均异常(3/3)。椎动脉起源正常的患者,96.7%(445/460)的左侧椎动脉穿出颈椎横突孔的高度正常,92.0%(439/477)的右侧椎动脉穿颈椎横突孔高度正常。3组右侧椎动脉起源正常的患者椎动脉起始的相对位置的差异有统计学意义[C₄组:(24.3±2.1)%、C₅组:(47.9±6.6)%、C₆组:(77.7±1.7)%,H=20.178,P<0.001]。结论椎动脉起始位置异常时,其穿出颈椎横突孔的高度多异常。右侧椎动脉的起始相对位置越靠近右侧颈总动脉时,穿出颈椎横突孔的高度越高;而越靠近右侧甲状颈干,穿出颈椎横突孔的高度越低。