Arterial abnormalities and associated variations of the vertebrobasilar system on the brain base: apropos of a rare case / Anomalías arteriales y variaciones asociadas del sistema vertebrobasilar en la base del cerebro: un caso raro

SUMMARY: The presented case characterizes an association of primitive and definitive arteries with variations on the cadaveric brain base of a very old man. This case is found by the retrospective review of the data archive obtained during many years of cooperation of the author and co-authors. Fenestration of the (ectatic) basilar artery, partial and total duplication of some cerebellar arteries was associated with other variations of the vertebrobasilar and carotid systems. Although this is a case autopsied because of the myocardial infarction, the peculiarity of the case lies in the absence of the aneurysm based on the fenestration or dissection of one of the cerebral arteries.

RESUMEN: El caso presentado caracteriza una asociación de arterias primitivas y definitivas con variaciones sobre la base cerebral cadavérica de un anciano. Este caso se encuentra mediante la revisión retrospectiva de datos obtenidos durante muchos años de un trabajo de cooperación del autor y coautores. La fenestración de la arteria basilar (ectásica), la duplicación parcial y total de algunas arterias cerebelosas se asoció con otras variaciones de los sistemas vertebrobasilar y carotídeo. Si bien se trata de un caso de autopsia a causa de un infarto del miocardio, la peculiaridad del caso radica en la ausencia del aneurisma en base a la fenestración o disección de una de las arterias cerebrales.

Prevención, manejo y seguimiento de las lesiones de la arteria vertebral. Conocimiento actual de los cirujanos de columna de la Argentina / Prevention, management and monitoring of vertebral artery injuries. Current state of knowledge of spine surgeons in Argentina

Introducción: La lesión de la arteria vertebral es un evento grave. El objetivo del estudio fue evaluar el grado de conocimiento de los cirujanos de columna en la Argentina sobre las medidas diagnósticas y terapéuticas de la lesión de la arteria vertebral. Materiales y métodos: Se realizó un estudio descriptivo observacional mediante una encuesta difundida a través de la AANC y la SAPCV. Resultados: Se recibieron 157 respuestas. El 47,4% considera relevante evaluar la anatomía de la arteria vertebral en todo tipo de patología mediante métodos angiográficos. La mitad de los encuestados diagnosticó una variante anatómica de la arteria. El 29,2% manifestó haber tenido en su práctica una lesión de la arteria. Solo el 35% tiene un protocolo de acción para el manejo de este evento adverso. El 77% adopta como primera medida el taponamiento. En el seguimiento posquirúrgico, la mayoría estudia el estado final mediante métodos angiográficos. Alrededor del 10% procuraría instaurar alguna medida de profilaxis antitrombótica. El 76,6% dispone de Servicio de Hemodinamia con cirujano endovascular. Conclusión: Esta complicación está subestimada. Menos de la mitad de los cirujanos utiliza, como rutina, herramientas de diagnóstico de posibles alteraciones anatómicas. No se han observado protocolos de manejo ni seguimiento de estas lesiones. Nivel de Evidencia: IV

Introduction: Vertebral artery injury is a serious event. The objective of this work is to evaluate the degree of knowledge of spinal surgeons in Argentina regarding the diagnostic and therapeutic measures of vertebral artery injury. Materials and methods: An observational descriptive study was carried out through a survey transmitted through AANC and SAPCV. Results: Of 157 responses, 47.4% consider it relevant to evaluate the anatomy of the vertebral artery in all types of pathology by angiographic methods. Half of those surveyed diagnosed an anatomical variant of the artery, 29.2% reported having encountered an artery injury during their practice and only 35% had an action protocol for the management of this adverse event. 77% adopted tamponade as their first measure. In the postoperative follow-up, the majority of surgeons studied the final state of the situation using angiographic methods. Around 10% would try to establish some measure of antithrombotic prophylaxis. 76.6% have an hemodynamics service with an endovascular surgeon. Conclusion: We found an underestimation of this complication. Less than half of surgeons routinely use diagnostic tools for possible anatomical changes. Management or monitoring protocols for these injuries have not been observed. Level of Evidence: IV

The arterial circle described by Willis, and the contribution of his predecessors / O círculo arterial descrito por Willis e a contribuição de seus predecessores

The description of arteries at the base of the human brain forming an 'arterial circle', named after Thomas Willis, has had a long history after the restoration of human dissection, partly due to the studies of many outstanding anatomists that preceded Willis. He provided, with the collaboration of Richard Lower and Christopher Wren, the first incontestable complete description, as recognized nowadays, accompanied by a superb illustration. Additionally, he presented an explanation for its meaning, indicating for the first time the functional significance of this structure, in health and disease. However, it should be recognized that the initial studies of the arteries of the base of the human brain by Willis' predecessors, as well as those from ancient times, despite their fragmentary descriptions, were certainly pivotal in paving the way for further and more detailed knowledge of this vascular formation.

A descrição das artérias da base do cérebro humano, formando um 'círculo arterial', designado com o nome de Thomas Willis, tem uma longa história após o restauro de dissecções humanas, em parte devido aos estudos de muitos anatomistas de renome que precederam Willis. Ele proveu, com a colaboração de Richard Lower e Christopher Wren, a primeira descrição completa e incontestável, assim como a reconhecida atualmente, acompanhada por uma ilustração soberba. Adicionalmente, apresentou uma explicação quanto ao seu significado, indicando pela primeira vez a importância funcional dessa estrutura, na saúde e na doença. Entretanto, deve ser reconhecido que os estudos iniciais das artérias da base do cérebro humano pelos predecessores de Willis, assim como os de tempos antigos, apesar de suas descrições fragmentárias, certamente foram fulcrais na pavimentação do caminho para o conhecimento mais avançado e detalhado dessa formação vascular.

Traumatic Dissection of Arterial Cervical Vessels: Report of Two Cases and Literature Review

Even though traumatic dissection of cervical arterial vessels is themajor cause of stroke among adults, it is still an underdiagnosed disease in neurosurgical emergencies, since most patients do not have or present subtle clinical signs in the acute phase. The authors report two interesting cases of cervical artery dissection with different traumatic mechanisms and present a broad literature review about this subject.

Presentation of cerebral and cervical arterial dissections in Botucatu, Brazil: case series / Apresentação de dissecções arteriais cerebrais e cervicais em Botucatu, Brasil: uma série de casos

Abstract Spontaneous dissection of the cervical and cerebral arteries is an important cause of stroke and disability in young patients. In this report, the authors present a case series of patients with spontaneous carotid, vertebral, or cerebral artery dissection who underwent digital angiography. A review of the published literature on this subject is also presented.

Resumo A dissecção espontânea das artérias cervicais e cerebrais é uma causa importante de acidente vascular cerebral e incapacidade em pacientes jovens. Neste relato, é apresentada uma série de casos de pacientes com dissecção espontânea da artéria carótida, vertebral ou cerebral submetidos à angiografia digital. Além disso, é fornecida uma revisão da literatura sobre esse assunto.

Endovascular management of dissecting posterior cerebral artery aneurysm associated with persistent hypoglossal artery: A case report / Tratamento endovascular do aneurisma dissecante da artéria cerebral posterior associado à artéria hipoglossa persistente: relato de caso

Abstract Persistent embryological connections between the anterior and posterior circulations are rare entities. Persistent hypoglossal artery is the second most common persistent carotid-basilar anastomosis. As it is often associated with hypoplasia of vertebral arteries, it poses a challenge during endovascular interventions. We present a case of a 32-year-old woman who presented with occipital headache of four weeks' duration. Magnetic Resonance Angiography showed hypoplastic vertebral arteries with a persistent hypoglossal artery arising from the cervical segment of the left internal carotid artery and supplying the entire posterior circulation, associated with a dissecting aneurysm of the right posterior cerebral artery. Endovascular parent vessel occlusion was performed for the dissecting posterior cerebral artery aneurysm by navigating the guide catheter, microwire, and microcatheter through the persistent hypoglossal artery because the vertebral arteries were hypoplastic. Post-intervention, the patient did not develop any neurological deficit and was discharged in a stable condition.

Resumo Conexões embriológicas persistentes entre as circulações anterior e posterior são entidades raras. A artéria hipoglossa persistente é a segunda anastomose carotídeo-basilar persistente mais comum. Como está frequentemente associada à hipoplasia das artérias vertebrais, apresenta um desafio durante as intervenções endovasculares. Apresentamos o caso de uma mulher de 32 anos que apresentou cefaleia occipital com duração de quatro semanas. A angiografia por ressonância magnética mostrou artérias vertebrais hipoplásicas com artéria hipoglossa persistente surgindo do segmento cervical da artéria carótida interna esquerda e suprindo toda a circulação posterior com um aneurisma dissecante da artéria cerebral posterior direita. A oclusão endovascular do vaso parental foi realizada para o aneurisma da dissecção da artéria cerebral posterior pela passagem de cateter guia, microfio e microcateter pela artéria hipoglossa persistente, pois as artérias vertebrais eram hipoplásicas. Após a intervenção, a paciente não apresentou déficit neurológico e recebeu alta em uma condição estável.

Cerebellar infarction after sneezing

SUMMARY Vertebral Artery Dissection (VAD) is a rare condition that can be caused by a wide amplitude of neck movement, which injures the vessel wall and can cause ischemia in the cerebellum. We present a 37-year-old man with herniated lumbar disc and allergic rhinosinusitis, which caused sneezing spells. After one of these bouts with a ricochet of the head, he presented C3 misalignment with local pain. Twenty-one days later, affected by a new crisis, he presented left temporal headache, nystagmus, and vertigo. After 3 days, Magnetic Resonance Imaging (MRI) identified 2 regions of cerebellar ischemia and filling failure of the right vertebral artery. After 2 days, Computed Angiotomography (CT Angiography) was performed and showed right VAD with a local thrombus, without aneurysmal signs. Transcranial Doppler did not indicate an increase in blood flow from this artery. The suggested treatment involved administration of anticoagulant Apixabana 5mg, 12/12h, for 3 months, until the condition was reevaluated with new Angio CT and MRI. It was recommended that the patient was released from work for 1 month and forbidden from doing intense physical exercises for 3 months; however, due to setbacks, these deadlines were extended until a new appointment, 4 months after the first visit. The new tests showed no changes, indicating that the condition was stable. This case aims to indicate the possible investigations of the diagnosis and therapeutic options of the rare association between VAD with cerebellar infarction in a well-documented case.

RESUMO A Dissecção da Artéria Vertebral (DAV) é quadro raro que pode ser causado por movimentação de grande amplitude do pescoço, que lesiona a parede desse vaso, podendo provocar isquemia no cerebelo. Apresentamos um homem de 37 anos, com hérnia de disco e rinossinusite alérgica que lhe causava crises de espirros em salva (CE). Após uma dessas crises com ricocheteamento da cabeça, apresentou desalinhamento de C3 com dor local. Vinte e um dias depois, acometido por nova crise, apresentou cefaleia temporal esquerda, nistagmo e vertigem. Decorridos 3 dias, o paciente foi submetido a Ressoânncia Magnética (RM), que identificou 2 regiões de isquemia cerebelar e enchimento comprometido da artéria vertebral direita. Após 2 dias, foram feitos Angiotomografia Computadorizada (Angio TC), que constatou DAV direita com trombo local, sem sinais aneurismáticos, e Doppler Transcraniano, que não indicou aumento do fluxo sanguíneo dessa artéria. O tratamento sugerido envolvia administração de anticoagulante Apixabana 5mg, 12/12h, por 3 meses, até que o quadro fosse reavaliado com novas Angio TC e RM. Foi recomendado que o paciente ficasse afastado do trabalho por 1 mês e de exercícios físicos intensos por 3 meses, porém devido a contratempos, esses prazos foram prorrogados até nova consulta, 4 meses após a primeira. Os novos exames não apresentaram alterações, indicando que o quadro estava estável. Esse caso tem como objetivo indicar as possíveis investigações do diagnóstico e opções terapêuticas da rara associação entre DAV com infarto cerebelar em caso bem documentado.

Safety ranges in V3 segment of the vertebral artery for surgical procedures at the craniocervical junction / Rangos de seguridad en el segmento V3 de la arteria vertebral para procedimientos quirúrgicos en la unión craneocervical

The aim of this study was to establish safety ranges for the third vertebral artery segment (V3) for craneocervical procedures. Injury to V3 represents a potentially catastrophic complication. Its tortuous path and complex relationship with neighboring structures, increasing the risk. Ten male adult cadavers (20 vertebral arteries) with arterial infiltration of red latex were studied. The length, angles and anatomical measurements were obtained between the selected surgical landmarks and the portions of V3 segment. The horizontal portion has a length of 32.7 ± 3.6 mm with an angulation of 115.1 ± 8.3 degrees. The mean distances of the horizontal portion were: from the midline to the V3 groove of C1 posterior arch (24.7 ± 6.3 mm); from C1 pars interarticularis to the V3 distal loop of V3 (8.9 ± 1.4 mm). The vertical portion has a length 32.5 ± 5.6 mm with an angulation of the proximal loop of 113.6 ± 5.8 degrees. The mean distances between the C2 spinous process to the medial surface of the distal loop (43.8 ± 4.2 mm); from the C1-C2 joint to the V3 vertical portion (9.5 ± 1.5 mm); from C2 pars interarticularis to V3 in the C2 transverse foramen (6.5 ± 3.4 mm); from C2 pars interarticularis to V3 in the C1 transverse foramen (17.5 ± 4.5 mm). We reported four potential sites where V3 can be injured during four different surgical procedures: exposure of the posterior arch of C1, and pars interarticularis of C1 in the horizontal portion and exposure of the C1C2 joint, and placement of C1-C2 transarticular screws one in the vertical portion. We provide measurements of redundancy and safety ranges to reduce the risk of injury to the V3 segment during craniocervical surgical procedures.

El objetivo de este estudio fue establecer rangos de seguridad en el tercer segmento de arteria vertebral (V3) para cirugías de la región craneocervicales. La lesión de V3 representa una complicación potencialmente catastrófica. Su tortuoso trayecto y compleja relación con las estructuras aledañas, aumenta el riesgo. Se estudiaron diez cadáveres adultos masculinos (20 arterias vertebrales) con infiltración arterial de látex rojo. La longitud, ángulos y medidas anatómicas se obtuvieron respecto a los puntos de referencia quirúrgicos y las porciones del segmento V3. La porción horizontal tiene una longitud de 32,7 ± 3,6 mm con una angulación de 115,1 ± 8,3 grados. Las distancias medias de la porción horizontal fueron: desde la línea media hasta el surco V3 del arco posterior C1 (24,7 ± 6,3 mm); desde C1 pars interarticularis hasta el bucle distal V3 de V3 (8,9 ± 1,4 mm). La parte vertical tiene una longitud de 32,5 ± 5,6 mm con una angulación del bucle proximal de 113,6 ± 5,8 grados. Las distancias medias entre el proceso espinoso C2 y la superficie medial del bucle distal (43,8 ± 4,2 mm); desde la unión C1-C2 hasta la porción vertical V3 (9,5 ± 1,5 mm); de C2 pars interarticularis a V3 en el foramen transversal C2 (6,5 ± 3,4 mm); de C2 pars interarticularis a V3 en el foramen transversal C1 (17,5 ± 4,5 mm). Informamos cuatro sitios potenciales donde la V3 puede lesionarse durante cuatro procedimientos quirúrgicos diferentes: exposición del arco posterior de C1 y pars interarticularis de C1 en la porción horizontal y exposición de la articulación C1-C2, y colocación de C1-C2 Tornillos transarticulares uno en la porción vertical. Proporcionamos mediciones de los rangos de redundancia y seguridad para reducir el riesgo de lesiones en el segmento V3 durante procedimientos quirúrgicos craneocervicales.

Origin of the Posterior Inferior Cerebellar Artery over the C1 Posterior Arch / Origem da artéria cerebelar inferoposterior sobre o arco posterior de C1

Resumo The posterior inferior cerebellar artery usually arises from the intracranial segment (V4) of the vertebral artery. Despite its mean diameter of 2 mm, it usually irrigates important areas of the brain. When occluded, whether due to trauma or surgery, it may cause infarction in the brain stem and cerebellum. The present report describes a case of incidental finding of a posterior inferior cerebellar artery arising from the cervical segment (V3) of the vertebral artery, demonstrated by angiography. The findings were recorded and compared to those of earlier publications. Brief explanations regarding anatomy, vascular anomalies and embryology were provided. A literature review showed that anomalous branches of the cervical segment of the vertebral artery are infrequent andmust be known. A better understanding of anatomy and its variations enables an accurate topographic diagnosis, as well as the planning of the optimal surgical approach and therapy. Knowledge of this anatomical variation is essential because, if it is mistaken for a muscle branch and coagulated, this can cause ischemia and disabling sequelae.

Resumo A artéria cerebelar inferoposterior geralmente nasce do segmento intracraniano (V4) da artéria vertebral. Apesar de ter diâmetro médio de 2 mm, usualmente irriga áreas eloquentes do encéfalo. Quando ocluída, seja por trauma ou cirurgia, pode causar infarto no tronco encefálico e no cerebelo. Apresentamos um caso de artéria cerebelar inferoposterior com origem anômala no segmento cervical (V3) da artéria vertebral, demonstrado por angiografia. Os resultados foram registrados e comparados com os de publicações anteriores. Foram fornecidas breves explicações sobre a anatomia, anomalias vasculares e embriologia. A revisão da literatura mostrou que os ramos anômalos do segmento cervical da artéria vertebral são infrequentes e devem ser conhecidos. Uma melhor compreensão da anatomia e suas variações permite fazer um diagnóstico topográfico preciso, bem como planejar a abordagem e a terapia cirúrgicas ideais. O conhecimento dessa variação anatômica é essencial, pois, se confundida com um ramo muscular e coagulada, pode causar isquemia com sequelas incapacitantes.

Síndrome de Barré-Lieou en un anciano / Barre-Lieou syndrome in an elderly

Se describe el caso clínico de un anciano de 85 años de edad a quien se le diagnosticó síndrome de Barré-Lieou en el Hospital Provincial General Docente Dr. Antonio Luaces Iraola de Ciego de Ávila, por lo cual fue atendido en consultas multidisciplinarias. Mediante la radiografía contrastada del esófago se observó compresión extrínseca de su tercio distal por grandes osteofitos cervicales anteriores, así como estrechamiento anterior y posterior desde la cuarta hasta la séptima vértebras cervicales; asimismo, las imágenes de la resonancia magnética de cráneo y columna cervical permitieron comprobar la presencia de complejos disco-osteofitos de vértebras cervicales con edema óseo, de carácter compresivo. Se comenta sobre el tratamiento empleado y se ofrecen las sugerencias terapéuticas de los expertos en el tema.

The case report of a 85 years elderly to whom the Barré-Lieou syndrome was diagnosed in Dr. Antonio Luaces Iraola Teaching General Provincial Hospital in Ciego de Ávila is described, reason why he was assisted in multidisciplinary visits. By means of the contrasted x-ray of the esophagus, extrinsic compression of his distal third was observed caused by huge anterior cervical osteophytes, as well as early and posterior narrowing of the fourth to the seventh cervical vertebrae; also, the magnetic resonance images of skull and cervical spine allowed to check the presence of disk-osteophytes complexes of cervical vertebrae, with bony edema, of compressive character. It is commented on the used treatment and the therapeutic indications of experts in the topic are offered.

Correlação entre aterosclerose carotídea e disfunção ventricular esquerda ao ecocardiograma / Correlation between carotid atherosclerosis and left ventricular dysfunction at echocardiography

As doenças cardiovasculares são a maior causa de morbimortalidade no mundo. A prevenção primária, por meio do diagnóstico precoce, é necessária para possibilitar o tratamento adequado e controlar a evolução da doença, reduzindo a mortalidade e os gastos em saúde pública. Correlacionar aterosclerose em artéria carótida (avaliada pelo Eco Doppler) e disfunção ventricular esquerda (avaliada pelo ecocardiograma), além de correlacionar tais achados com o risco cardiovascular dos pacientes estudados. Método: Foram analisados 286 prontuários de pacientes que realizaram os exames Eco Doppler carotídeo e ecocardiograma transtorácico. Os dados analisados foram: presença de placa aterosclerótica e grau de estenose, fração de ejeção do ventrículo esquerdo e presença de alterações contráteis difusas ou segmentares do ventrículo esquerdo. Resultados: Dos 238 laudos de Eco Doppler carotídeo, 18 tinham estenose maior que 70% em artéria carótida e 14 destes apresentavam alteração contrátil do ventrículo esquerdo (p = 0,045). Dos pacientes que tinham risco cardiovascular muito alto, 61 apresentavam estenose em artéria carótida (p < 0,001); 51 pacientes com risco cardiovascular muito alto apresentavam alteração contrátil (p < 0,001). Dos 266 laudos de ecocardiograma, 37 registravam fração de ejeção do ventrículo esquerdo reduzida. Desses, 25 tinham risco cardiovascular muito alto (p < 0,001). Conclusão: Houve relação positiva entre estenose de artéria carótida, redução da fração de ejeção do ventrículo esquerdo e alteração contrátil do ventrículo esquerdo (difusa ou segmentar) com risco cardiovascular muito alto. Também foi possível correlacionar a estenose carotídea com alteração contrátil, apesar deste estudo não demonstrar correlação entre estenose carotídea e redução da fração de ejeção do ventrículo esquerdo

Cardiovascular diseases are the leading cause of morbidity and mortality worldwide. Primary prevention, through early diagnosis, is necessary to enable proper treatment and control disease progression, reducing mortality and public health expenditures. Objective: Correlate carotid artery atherosclerosis (evaluated by Doppler echocardiography) and left ventricular dysfunction (evaluated by echocardiography) and to correlate the findings with the patients' cardiovascular risk. Method: A total of 286 medical records of patients who underwent carotid Doppler echocardiography and transthoracic echocardiography were analyzed. The data analyzed were: presence of atherosclerotic plaque and degree of stenosis, left ventricular ejection fraction and presence of diffuse or segmental left ventricular contractile disorders. Results: Of the 238 reports of carotid Doppler echocardiography, 18 had stenosis greater than 70% in the carotid artery and 14 of those had left ventricular contractile disorders (p = 0.045). Of the patients with very high cardiovascular risk, 61 had carotid artery stenosis (p < 0.001); 51 patients with very high cardiovascular risk had contractile disorders (p < 0.001). Of the 266 echocardiography reports, 37 had reduced left ventricular ejection fraction. Of these, 25 had very high cardiovascular risk (p < 0.001). Conclusion: There was a positive relationship between carotid artery stenosis, reduced left ventricular ejection fraction and left ventricular (diffuse or segmental) contractile disorder with very high cardiovascular risk. It was also possible to correlate carotid stenosis with contractile disorder, although this study did not demonstrate any correlation between carotid stenosis and reduced left ventricular ejection fraction

Rotational vertebral artery syndrome treated via an anterior approach and selective decompression only

We present the case of a 38-year-old male who complained of repeated dizziness and syncope. Rotational vertebral artery syndrome (RVAS) was diagnosed via videonystagmoraphy (VNG), computed tomography angiography (CTA) and three-position digital subtraction angiography (DSA). In the neutral position, CTA and DSA revealed left vertebral artery (VA) stenosis at the C2 transverse foramen and right VA hypoplasia. When the head was turned to the right, the blood flow stopped at the C2 level. The bony structure around the VA at the C2 transverse foramen was decompressed via an anterior surgical approach, and the symptoms resolved. This case present the precise stenotic point evaluation by three-position DSA is crucial for the planning of surgical treatment.

Anatomic Considerations of Anterior Transarticular Screw Fixation for Atlantoaxial Instability

STUDY DESIGN: Cadaveric, observational study.PURPOSE: Atlantoaxial instability (AAI) is characterized by excessive movement at the C1–C2 junction between the atlas and axis. An anterior surgical approach to expose the upper cervical spine for internal fixation and bone grafting has been developed to fix AAI. Currently, no anatomic information exists on the anterior transarticular atlantoaxial screw or screw and plate fixation between C1 and C2 in the Indian population. The objective of this study is to assess the anatomic landmarks of C1–C2 vertebrae: entry point, trajectory, screw length, and safety of the procedure.OVERVIEW OF LITERATURE: Methods outlined by Magerl and Harms are the optimal approaches among the dorsal techniques. Contraindications for these techniques include aberrant location of vertebral arteries, fractures of C1–C2 posterior structures. In these cases, anterior transarticular fixation is an alternative. Several available screw insertion trajectories have been reported. Biomechanical studies have demonstrated that adequate rigidity of this fixation is comparable with posterior fusion techniques.METHODS: Direct measurements using Vernier calipers and a goniometer were recorded from 30 embalmed human cadavers. The primary parameters measured were the minimum and maximum lateral and posterior angulations of the screw in the sagittal and coronal planes, respectively, and optimum screw length, if it was placed accurately.RESULTS: The posterior and lateral angles of screw placement in the coronal and sagittal planes ranged from 16° to 30° (mean±standard deviation [SD], 23.93°±3.93°) and 8° to 17° (mean±SD, 13.3°±2.26°), respectively. The optimum screw length was 25–38 mm (mean±SD, 28.76±3.69 mm).CONCLUSIONS: If the screw was inserted without lateral angulation, the spinal canal or cord could be violated. If a longer screw was inserted with greater posterior angulation, the vertebral artery at the posterior or posterolateral aspect of the C1 superior facet could be violated. Thus, 26° and 30° of lateral and posterior angulations, respectively, are the maximum angles permissible to avoid injury of the vertebral artery and violations of the spinal canal or atlanto-occipital joint.

Posterior Inferior Cerebellar Artery Infarction Originating at C1-2 after C1-2 Fusion / 대한신경손상학회지

Vertebral artery injuries associated with C1 lateral mass screw insertion rarely occur during C1-2 fusion. The posterior inferior cerebellar artery (PICA) is uncommonly located at the C1 lateral mass insertion position. A 71-year-old woman with atlanto-axial subluxation and cord compression underwent C1-2 fusion. Sixth nerve palsy and diplopia were detected postoperatively, and decreased consciousness occurred on postoperative day 4. Brain magnetic resonance image (MRI) and computed tomography (CT) revealed PICA infarction. In the preoperative CT angiography, the PICA originated between the C1 and C2 level. In the postoperative CT scan, the PICA was not visible. The patient was treated conservatively for two weeks and recovered. PICA originating between the C1 and C2 level comprises 1.1–1.3% of cases. Therefore, vertebral artery anomalies should be evaluated prior to C1-2 fusion to prevent vessel injuries.

Vertebral Artery Dissection Presenting with Acute Infarction in Cervical Spinal Cord and Cerebellum

We describe a case of vertebral artery dissection (VAD) presenting with acute infarctions in cervical spinal cord and cerebellum in a 78-year-old man. Diffusion-weighted magnetic resonance (MR) imaging of the brain demonstrated diffusion-restricted lesions in the right cerebellum and sagittal T2-weighted MR imaging of spinal cord showed a hyperintense lesion of the cervical spinal cord at C2-C4 level. Right VAD was identified by transfemoral cerebral angiography and computed tomography angiography which showed segmental occlusion in the right vertebral artery.