Posteroinferior Cerebellar Artery Research Articles

Vascular reconstruction related to the extracranial vertebral artery: the presentation of the concept and the basis for the establishment of the bypass system.

The intracranial vertebrobasilar artery system has a unique hemodynamic pattern (vessel trunk converged bilateral flow with three groups of perforators directly arising from it), is embedded within intense osseous constraints, and is located far from conventional donor vessels. Two major traditional modalities of posterior circulation revascularization encompass the superficial temporal artery to the superior cerebellar artery and the occipital artery to the posteroinferior cerebellar artery anastomosis, which are extracranial-intracranial low-flow bypass with donor arteries belonging to the anterior circulation and mainly supply focal perforators and distal vascular territories. As our understanding of flow hemodynamics has improved, the extracranial vertebral artery-related bypass has further evolved to improve the cerebral revascularization system. In this article, we propose the concept of "vascular reconstruction related to the extracranial vertebral artery" and review the design philosophy of the available innovative modalities in the respective segments. V1 transposition overcomes the issue of high rates of in-stent restenosis and provides a durable complementary alternative to endovascular treatment. V2 bypass serves as an extracranial communication pathway between the anterior and posterior circulation, providing the advantages of high-flow, short interposition grafts, orthograde flow in the vertebrobasilar system, and avoiding complex skull base manipulation. V3 bypass is characterized by profound and simultaneous vascular reconstruction of the posterior circulation, which is achieved by intracranial-intracranial or multiple bypasses in conjunction with skull base techniques. These posterior circulation vessels not only play a pivotal role in the bypass modalities designed for vertebrobasilar lesions but can also be implemented to revascularize the anterior circulation, thereby becoming a systematic methodology.

Hemifacial spasm caused by tortuous vertebrobasilar artery: a case report

BackgroundHemifacial spasm is a rare movement disorder. Prevalence estimates worldwide was 14.5 per 100,000 women and 7.4 per 100,000 men. Hemifacial spasm generally caused by compression of blood vessels at the root entry zone of the facial nerve in the brainstem, tortuous anteroinferior cerebellar artery (AICA) and posteroinferior cerebellar artery (PICA). Direct compression by vertebrobasilar dolichoectasia (VBD) with coincidence cavernoma is extremely rare.Case reportA 50-year-old woman with right hemifacial spasm for 1 year, with a history of hypertension for 10 years, did not take medication regularly. MRI MRA was performed showing suspicious dolichoectasia in the vertebrobasilar artery and cavernoma in the left basal ganglia. Then digital subtraction angiography was performed, it was found that the tortuous vertebrobasilar junction artery with a curve to the right caused right hemifacial spasm.ConclusionVascular imaging examination is important to do to find the cause of hemifacial spasm suspected to be due to vascular causes. The finding of two types of intracranial vascular malformations should be explored further. Therefore, the selection of therapy and management becomes more appropriate.

Challenging the diagnosis of a posterior circulation dissecting aneurysm

I ntracranial vertebral dissections have polymorphs clinical presentations and can lead to haemorrhagic complications if they are intracranial. We here describe a case of a thrombosed dissecting aneurysm of postero-inferior cerebellar artery (PICA) revealed by a Wallenberg syndrome preceded by headaches. A 23-year-old patient, without neurological or vascular past medical history, was admitted for dizziness preceded by headache. The clinical examination on admission revealed an incomplete Wallenberg syndrome, associating hemiface sensitive deficit, Horner's syndrome, dysmetria and nystagmus. The brain MRI showed a latero-medullary infarct with a homolateral PICA thrombosed dissecting aneurysm. The diagnosis of intracranial dissecting aneurysms needs particular caution because aneurysm sac thrombosis can give false reassurance on angiographic MR sequences. Moreover, the anatomic features of intracranial artery walls make them prone to sub-adventitial dissection and subsequent subarachnoid haemorrhages. Therefore, antithrombotic therapy should be used with caution, due to the risk of bleeding in these intracranial dissections.

Video Head Impulse Test e doenças do sistema nervoso central: uma revisão integrativa

ABSTRACT Purpose To verify the applicability of the Video Head Impulse Test (vHIT) in central nervous system (CNS) diseases, as well as the results found and the diseases described. Research strategy Integrative literature review, in which nine electronic databases were searched using the keyword “video head impulse test”. Selection criteria Studies that used the vHIT in the diagnosis of CNS diseases were included, and studies published before 2009, studies that performed other clinical investigation procedures or that concerned the diagnosis of peripheral vestibular diseases were excluded. Results The final sample consisted of 18 studies. The verified results show that the vestibulo-ocular reflex (VOR) has shown alteration in this population. Suggestive findings of central involvement were observed, such as lower gain or average VOR in the vertical semicircular canals than in the lateral ones, increased gain, the negative correlation of gain with disease severity in Spinocerebellar Ataxia Type 3, cutoff point of 0.70, and gain asymmetry of less than 20% to differentiate vestibular neuritis from a stroke in the medial branch of the posteroinferior cerebellar artery, normal gain with altered oculomotor tests, presence of spontaneous vertical nystagmus, as well as alterations in the VOR with and without visual enhancement, in saccadic pursuit, and the tilt deviation test. Conclusion We found that the vHIT applies to the assessment of high-frequency VOR in individuals with CNS diseases since it provided clinical evidence of changes in peripheral and central vestibular function in different neurological conditions

Posteroinferior Cerebellar Artery (PICA) Fusiform Aneurysm Ruptured Related with a Pure Arterial Malformation: Case Report and Technical Note (NBCA Embolization under Roadmap-Fluoroscopy)

A 60 years old female with subarachnoid hemorrhage was diagnosed with a fusiform aneurysm in the right PICA related with a PAM in the digital subtraction angiography (DSA). With a negative super-selective Wada test; the patient was treated with embolization of the two lesions and the PICA for being in the same arterial territory with adhesive embolic liquid under roadmap fluoroscopy technique.

Bulbar watershed ischemic stroke: the comma-shaped sign-a case series.

Watershed infarcts can involve the brainstem, with lesions distributed across the terminal supply from the vertebral and cerebellar arteries. Brain imaging can highlight a comma-shaped lesion at the edge of vertebral and posteroinferior cerebellar artery vascularization territory. Such peculiar MRI lesion shape might suggest a watershed hypoperfusion etiology and direct workup towards causes of hemodynamic impairment, including postural hypotension, cardiac failure, or vertebral artery origin occlusion.

PICA injury secondary to anterior odontoid screw fixation: Case report of an exceptional complication

BackgroundOdontoid fracture is a common injury in the upper cervical spine that can sometimes be managed by anterior odontoid screw fixation. Case descriptionWe report the first case of iatrogenic postero-inferior cerebellar artery (PICA) injury while performing anterior odontoid screw fixation for a type II odontoid fracture in a 22-year-old man. Fisher grade 4 subarachnoid hemorrhage secondary to iatrogenic pseudoaneurysm formation was managed by the endovascular neuroradiologist. Odontoid fracture was then managed posteriorly using Harm's technique. Postoperative 12-month follow-up revealed good clinical and radiological results. CT scan showed fusion. Complete exclusion of the pseudo aneurysm with a mild stroke in the inferior left cerebellar hemisphere were noted on the MRI. There were no cerebellar ataxia or swallowing disorders. ConclusionTo the best of our knowledge, this is the first case report of iatrogenic PICA injury in anterior odontoid screw fixation. The patient was well managed in our institution within a multidisciplinary team. We recommend that surgical management of odontoid fractures should be performed in expert centres.

Posteroinferior Cerebellar Artery (PICA) Fusiform Aneurysm Ruptured Related with a Pure Arterial Malformation: Case Report and Technical Note (NBCA Embolization under Roadmap-Fluoroscopy)

Background: The pure arterial malformation (PAM) lesion has been recently described as a vascular pathology characterized by the sole presence of coiled, sometimes ectatic, arterial loops. 2% of the fusiform aneurysms are located in the vertebral-posterior inferior cerebellar arteries. Case Presentation: A 60 years old female with subarachnoid hemorrhage was diagnosed with a fusiform aneurysm in the right PICA related with a PAM in the digital subtraction angiography (DSA). With a negative super-selective Wada test, the patient was treated with embolization of the two lesions and the PICA for being in the same arterial territory with adhesive embolic liquid under roadmap fluoroscopy technique. The patient had a satisfactory clinical evolution and no added neurological deficit, so she was discharged 3 days after the treatment. Conclusion: These two vascular lesions located in the same artery are very rare and more in the PICA territory. It is important to make the best decision to treat them because of the potential complications; that’s why the procedure was supported with super-selective Wada test and neuromonitoring of the PICA territory. The injection of the mixture of NBCA and Lipiodol® under roadmap fluoroscopy is very safe.

Síndrome de Wallenberg asociado a una arteria vertebral derecha hipoplásica bifurcada: Primer reporte de un caso en el Perú.

El síndrome de Wallenberg es el accidente cerebrovascular isquémico más común de la circulación posterior, causado por una obstrucción aterotrombótica en la arteria vertebral o la arteria cerebelosa posteroinferior. Esta oclusión origina una isquemia en la porción lateral del bulbo que resulta en la triada representativa del síndrome de Horner, ataxia ipsilateral a la lesión y alteraciones sensitivas. El riesgo de padecer este cuadro es mayor si se tiene variaciones anatómicas tales como una arteria vertebral hipoplásica y/o duplicada. Se presenta el caso de una mujer de 45 años admitida por hipoestesia en el lado derecho del rostro y en el hemicuerpo izquierdo, así como disfagia y vómitos. La resonancia magnética reveló una lesión isquémica en la zona bulbar lateral derecha; en la angiorresonancia se evidenció una arteria vertebral derecha hipoplásica, en tanto que la angio-TEM del cuello mostró una arteria vertebral derecha hipoplásica y bifurcada. En base a la clínica y exámenes radiológicos se confirmó el diagnóstico de Síndrome de Wallenberg, causado por isquemia en el territorio de la arteria vertebral derecha hipoplásica bifurcada.

Posteroinferior Cerebellar Artery Aneurysms: Influence of Angioanatomy on the Safety of Flow Diversion Treatment.

Several anatomical variables critically influence therapeutic strategies for posteroinferior cerebellar artery (PICA) aneurysms and, specifically, the safety of flow diversion for these lesions. We review the microsurgical anatomy of the PICA, discussing and detailing these considerations in the treatment of aneurysms of this vessel from a theoretical perspective and in light of our previously published clinical results.

Conservative Management of Unruptured Spontaneous Intracranial Vertebral Artery Dissection

The present study investigated the clinical and morphological characteristics of the vertebrobasilar artery associated with vascular healing in patients with unruptured spontaneous intracranial vertebral artery (VA) dissection (VAD). We retrospectively reviewed the data from 69 consecutive patients with a diagnosis of unruptured VAD who were treated conservatively for ≥21 days from November 2003 to February 2018 at our institute. Univariate and multivariate analyses were performed to evaluate the clinical characteristics and morphological findings of VAD. Of the 69 patients, vascular normalization of VAD was observed in 26, including a significantly greater proportion of women and nonsmokers (P= 0.04 and P= 0.034, respectively). Patients with normalization of VAD had a significantly lower proportion of posteroinferior cerebellar artery involvement and a smaller vertebral-union-basilar angle of the nondissecting VA, smaller vertebral-union-vertebral angle, distal dissection from the VA union, and less basilar artery bending. Luminal irregularity/steno-occlusion of the VAD on the initial images exhibited vascular resolution/normalization in 25 patients (67.6%) on subsequent images. The morphology of VAD in the dominant or codominant VAs included fusiform/aneurysmal dilatation in 25 patients (78.1%). The morphology in the nondominant VA included luminal irregularity/steno-occlusion in 23 patients (62.2%). Spontaneous vascular normalization of unruptured spontaneous intracranial VAD might be associated with female sex, nonsmoking, no posteroinferior cerebellar artery involvement, a smaller vertebral-union-basilar angle and vertebral-union-vertebral angle, distal dissection from the VA union, less basilar artery bending, and luminal irregularity/steno-occlusion.

Case Presentation: Unusual Association Between Possible Bilateral Intraventricular Xanthogranulomas, Postero-inferior Cerebellar Artery Aneurysm and Thrombophilia

Abstract Introduction: Xanthogranulomas are rare, benign, usually asymptomatic, cutaneous tumors most frequently seen in children (juvenile xanthogranulomas). Some lesions can be found accidentally at randomly performed cerebral computer tomography (CT) or magnetic resonance imaging (MRI) or even on autopsy. Case report: We present the case of a 44 year-old woman, known with a thrombophilic disorder (PAI-1 gene mutation, MTHFR C677T and A1298C) on chronic anticoagulant treatment. The onset of symptoms was in 2010, when she presented paresthesia and lower limbs weakness. Two years later the patient presents with severe intermittent headache and left hemicrania and a cerebral angio-MRI is performed showing a left postero-inferior cerebellar artery aneurysm and two choroid plexus intraventricular masses in the lateral ventricles. The patient developed a new symptom, dysarthria in 2014 and in 2015 has multiple episodes of loss of consciousness, interpreted as epileptic seizures. Routine blood tests were within normal range, except for a high cholesterol level. The patient was tested for autoimmune, infectious, endocrine and metabolic diseases that were negative. Surgical treatment and biopsy from the lesion was proposed, however the patient refused both procedures. Conclusions: There is an association between xanthogranulomas localization and the choroid plexus, the most frequent CNS origin being in the trigon of the lateral ventricle. Our case does not resemble with any other case published, mostly because the unusual presentation, symptomatology and the association between xanthogranulomas, thrombophilia and postero-inferior cerebellar artery aneurysm which were never reported before in other cases of xanthogranulomas from the literature.

Anatomía del cerebelo en imágenes de TAC y resonancia magnética cerebral con correlación funcional

The cerebellum is a motor organ located in the posterior fossa, in close relation to brainstem. Its main function is in the starting of voluntary movements as well as their modulation. It is composed by the vermis in central location and both cerebellar hemispheres lateral to the vermis. It is irrigated mainly by three arteries: posteroinferior cerebellar, anteroinferior cerebellar and superior cerebellar arteries. The objective of this article is to review the functional anatomy of cerebellum and correlate it with neuroimaging.

Convexity Subarachnoid Hemorrhage, Pseudomonas Aeruginosa (PA) Infective Endocarditis and Left Atrial Appendage Occluder (LAAO) Device Infection. A Case Report.

An 83 year-old-man with left atrial appendage occluder (LAAO) developed Pseudomonas Aeruginosa (PA) infective endocarditis. MRI at day 3 of onset showed distal small infarcts in both middle cerebral arteries and left postero-inferior cerebellar artery territories. MRI at day 6 revealed two sites of convexity subarachnoid hemorrhage (cSAH). MRA and CTA failed to reveal a Mycotic aneurysm.The radiologic findings favor the assumption of necrosis of distal branches of mca or of pial arteries wall.This case present three unusual features: the presence of localized cSAH after initiation of antibiotherapy without mycotic aneurysm being individualized; the late occurrence of infective endocarditis after LAAO implantation; the very rare occurrence of PA in prosthetic infections.

Isolated Posteroinferior Cerebellar Artery Dissection Diagnosed by High-Resolution Vessel Wall MRI

Arterial dissection is an important cause of stroke. We report two cases of isolated posterior inferior cerebellar artery (PICA) dissection diagnosed by high-resolution vessel-wall MRI (HRVW-MRI). One subject complained of abrupt-onset vertigo and headache, and the other subject had headache, vertigo, and Horner syndrome. Conventional MRA showed only focal dilatation of the PICA, but HRVW-MRI revealed intramural hematoma and double-lumen contour in the PICA, suggesting arterial dissection. We suggest that the use of HRVW-MRI should be considered when diagnosing isolated PICA dissection in a PICA infarct with an unknown cause. Key Words: Isolated PICA dissection, High-resolution vessel-wall MRI, Arterial dissection

Anatomical Features and Clinical Significance of Radiculomuscular Artery Variants Involving the Suboccipital Segment of Vertebral Artery : Angiographic and Cadaver Studies.

To discuss the significance of the radiculomuscular artery in typical variations of the distal vertebral artery (VA) from the viewpoint of microsurgical anatomy. Some variations involving the radiculomuscular artery revealed by digital subtraction angiography (DSA) were recruited and studied together with our findings from cadaver dissections. A total of 29 variants were found in 26 patients, including 10 C‑2 vertebral origins of the posteroinferior cerebellar artery (PICA), 13 duplicated (12 patients) and 6 aberrant V3s. An aberrant V3 was observed in our cadaver specimen. Each of these variants involved only the distal part of the lateral spinal artery (LSA) that incorporates the radiculomuscular artery and the radiculomedullary branch. Using DSA two aberrant V3s were indicated and another one was verified by anatomical study as an extradural location. The radiculomuscular artery accounts for the C‑2 vertebral origin of the PICA, duplicated and aberrant V3, and extradural course of an aberrant V3 does exist. Aprobable extradural course of avariant between C‑2 and C‑1 should be kept in mind whenever each of the variations involving the radiculomuscular artery is detected by DSA or computed tomography angiography (CTA).

Long-term surgical results in microvascular decompression for hemifacial spasm: efficacy, morbidity and quality of life.

SUMMARYHemifacial spasm is a condition that may severely reduce patients' quality of life. Microvascular decompression is the neurosurgical treatment of choice. The objective of this work was to describe the efficacy and morbidity of microvascular decompression for hemifacial spasm, evaluate the long-term efficacy on the quality of life and investigate prognostic factors for failure of the procedure. A retrospective study of 446 cases of hemifacial spasm treated by 511 retrosigmoid microvascular decompression over 22 years was conducted. Epidemiological, clinical and imaging findings, treatment modalities and outcomes of patients with pre- and postoperative HSF-8 quality of life questionnaire were studied. Success rate was 82% after first surgery and 91.6% after revision surgery. A low rate of perioperative morbidity was found. Facial palsy was mostly transient (5.5% transient and 0.2% permanent) and cochleovestibular deficit was seen in 4.8% of patients. Revision surgery increased nervous lesions (10.6% to 20.7%). Mean quality of life scores were significantly improved from 18 to 2 over 32, evaluated 7.3 years after surgery. Predictive factors of surgical failure were single conflicts (p = 0.041), atypical vasculo-nervous conflicts involving other vessel than postero-inferior cerebellar artery (p = 0.036), such as vein (p = 0.045), and other compression sites than root exit zone (p = 0.027). Retrosigmoid microvascular decompression is a safe and effective treatment of hemifacial spasm. Revision surgery is not to be excluded in case of failure, but does place patients at risk for more complications. Quality of life is improved in the long-term, indicating objective and subjective satisfaction.

Surgical Treatment of Complex Cerebral Aneurysms Using Interposition Short Vein Graft.

Cerebral revascularization strategies may become necessary in select patients who present with challenging cerebral aneurysms. In this study, we present the techniques of a moderate-flow extra-intracranial bypass using a short interposition vein graft and concurrent aneurysm management. The short interposition vein graft was used for the reconstruction of complex cerebral aneurysms in nine patients. In eight of them, the superficial temporal artery (STA) main trunk was used as a donor site for the anastomosis of a short interposition vein graft, and an extracranial vertebral artery (VA) was used in one case. The vein grafts were implanted into the M2 of the middle cerebral artery (MCA) for the adjunctive treatment of internal carotid artery (ICA) aneurysms in three patients, into the A3 of the anterior cerebral artery (ACA) in one patient, into the P2 of the posterior cerebral artery (PCA) for the adjunctive treatment of complex PCA aneurysms in three patients, into the P3 of the PCA for the adjunctive treatment of a basilar artery (BA) trunk giant aneurysm in 1 patient, and into the postero-inferior cerebellar artery (PICA) for the adjunctive treatment of the VA dissecting aneurysm in one patient. All of the bypasses were patent. Intraoperative flow measurements confirmed a moderate flow-carrying capacity of the short interposition short vein graft (30-70 ml; mean: 43 ml/min). The STA main trunk to proximal MCA/PCA bypass and the extracranial VA to PICA bypass using short interposition vein grafts can provide sufficient blood flow and may be a reasonable alternative to the conventional EC-IC bypass/high-flow bypass.

Revisiting the far lateral approach in the treatment of lesions located at the craniocervical junction—Experiences from West China hospital, Sichuan University, Chengdu

Abstract Far lateral approach is a modification of the traditional lateral suboccipital approach that provides adequate exposure of the ventral craniocervical junction. Lesions located at ventral aspect of brainstem and foramen magnum areas like the lower clivus and premedullary area, intradural segment of the vertebral artery and its branches, including the posteroinferior cerebellar artery, the lower cranial and upper cervical nerves can be accessed through far lateral exposure. Between January 2011 and June 2014, 17 patients with lesions located at the ventral aspect of brainstem and foramen magnum areas were treated in our institution using a far lateral approach. We reviewed the nature of lesions, treatment strategy and outcomes in those 17 patients with the approval of institutional review board. There were 10 female and 7 male patients with age ranging from 6 to 58. Pathological entities comprised 11 meningiomas, 2 subarachnoid cyst, 2 epidermoid cysts, 1 vertebral aneurysm and 1 brainstem glioma. All patients recovered well after surgery without severe complications. In conclusion, far lateral approach provides an optimal exposure to the ventral aspect of brainstem and foramen magnum area which is sufficient for total removal of anteriorly placed well circumscribed lesions with zero retraction of neural axis.

Selective Vulnerability of Cortical Border Zone to Microembolic Infarct.

Endovascular procedures, including atrial fibrillation transcatheter ablation, may cause microembolization of brain arteries. Microemboli often cause small sized and clinically silent cerebral ischemias (SCI). These lesions are clearly visible on early postoperative magnetic resonance diffusion-weighted images. We analyzed SCI distribution in a population of patients submitted to atrial fibrillation transcatheter ablation. Seventy-eight of 927 consecutive patients submitted to atrial fibrillation transcatheter ablation were found positive for acute SCI on a postoperative magnetic resonance. SCI were identified and marked, and their coordinates were transformed from native space into the International Consortium for Brain Mapping/Montreal Neurological Institute space. We then computed the voxel-wise probability distribution map of the SCI using the activation likelihood estimation approach. SCI were more commonly found in the cortex. In supratentorial regions, SCI selectively involved cortical border zone between anterior, middle, and posterior cerebral arteries; in infratentorial regions, distal territory of posteroinferior cerebellar artery. Possible explanations include selective embolization, linked to the vascular anatomy of pial arteries supplying those territories, reduced clearance of emboli in a relatively hypoperfused zone, or a combination of both. This particular distribution of lesions has been reported in both animal models and in patients with microemboli of different sources. A selective vulnerability of cortical border zone to microemboli occurring during atrial fibrillation transcatheter ablation was observed. We hypothesize that such selectivity may apply to microemboli of different sources.